drivers/gpu/drm/display/drm_dp_mst_topology.c

   1 /*
   2  * Copyright © 2014 Red Hat
   3  *
   4  * Permission to use, copy, modify, distribute, and sell this software and its
   5  * documentation for any purpose is hereby granted without fee, provided that
   6  * the above copyright notice appear in all copies and that both that copyright
   7  * notice and this permission notice appear in supporting documentation, and
   8  * that the name of the copyright holders not be used in advertising or
   9  * publicity pertaining to distribution of the software without specific,
  10  * written prior permission.  The copyright holders make no representations
  11  * about the suitability of this software for any purpose.  It is provided "as
  12  * is" without express or implied warranty.
  13  *
  14  * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  15  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
  16  * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
  17  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
  18  * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
  19  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  20  * OF THIS SOFTWARE.
  21  */
  22
  23 #include <linux/bitfield.h>
  24 #include <linux/delay.h>
  25 #include <linux/errno.h>
  26 #include <linux/i2c.h>
  27 #include <linux/init.h>
  28 #include <linux/kernel.h>
  29 #include <linux/random.h>
  30 #include <linux/sched.h>
  31 #include <linux/seq_file.h>
  32 #include <linux/iopoll.h>
  33
  34 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
  35 #include <linux/stacktrace.h>
  36 #include <linux/sort.h>
  37 #include <linux/timekeeping.h>
  38 #include <linux/math64.h>
  39 #endif
  40
  41 #include <drm/display/drm_dp_mst_helper.h>
  42 #include <drm/drm_atomic.h>
  43 #include <drm/drm_atomic_helper.h>
  44 #include <drm/drm_drv.h>
  45 #include <drm/drm_print.h>
  46 #include <drm/drm_probe_helper.h>
  47
  48 #include "drm_dp_helper_internal.h"
  49 #include "drm_dp_mst_topology_internal.h"
  50
  51 /**
  52  * DOC: dp mst helper
  53  *
  54  * These functions contain parts of the DisplayPort 1.2a MultiStream Transport
  55  * protocol. The helpers contain a topology manager and bandwidth manager.
  56  * The helpers encapsulate the sending and received of sideband msgs.
  57  */
  58 struct drm_dp_pending_up_req {
  59         struct drm_dp_sideband_msg_hdr hdr;
  60         struct drm_dp_sideband_msg_req_body msg;
  61         struct list_head next;
  62 };
  63
  64 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
  65                                   char *buf);
  66
  67 static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port);
  68
  69 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
  70                                      int id,
  71                                      struct drm_dp_payload *payload);
  72
  73 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
  74                                  struct drm_dp_mst_port *port,
  75                                  int offset, int size, u8 *bytes);
  76 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
  77                                   struct drm_dp_mst_port *port,
  78                                   int offset, int size, u8 *bytes);
  79
  80 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
  81                                     struct drm_dp_mst_branch *mstb);
  82
  83 static void
  84 drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
  85                                    struct drm_dp_mst_branch *mstb);
  86
  87 static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
  88                                            struct drm_dp_mst_branch *mstb,
  89                                            struct drm_dp_mst_port *port);
  90 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
  91                                  u8 *guid);
  92
  93 static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port);
  94 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port);
  95 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
  96
  97 static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
  98                                                  struct drm_dp_mst_branch *branch);
  99
 100 #define DBG_PREFIX "[dp_mst]"
 101
 102 #define DP_STR(x) [DP_ ## x] = #x
 103
 104 static const char *drm_dp_mst_req_type_str(u8 req_type)
 105 {
 106         static const char * const req_type_str[] = {
 107                 DP_STR(GET_MSG_TRANSACTION_VERSION),
 108                 DP_STR(LINK_ADDRESS),
 109                 DP_STR(CONNECTION_STATUS_NOTIFY),
 110                 DP_STR(ENUM_PATH_RESOURCES),
 111                 DP_STR(ALLOCATE_PAYLOAD),
 112                 DP_STR(QUERY_PAYLOAD),
 113                 DP_STR(RESOURCE_STATUS_NOTIFY),
 114                 DP_STR(CLEAR_PAYLOAD_ID_TABLE),
 115                 DP_STR(REMOTE_DPCD_READ),
 116                 DP_STR(REMOTE_DPCD_WRITE),
 117                 DP_STR(REMOTE_I2C_READ),
 118                 DP_STR(REMOTE_I2C_WRITE),
 119                 DP_STR(POWER_UP_PHY),
 120                 DP_STR(POWER_DOWN_PHY),
 121                 DP_STR(SINK_EVENT_NOTIFY),
 122                 DP_STR(QUERY_STREAM_ENC_STATUS),
 123         };
 124
 125         if (req_type >= ARRAY_SIZE(req_type_str) ||
 126             !req_type_str[req_type])
 127                 return "unknown";
 128
 129         return req_type_str[req_type];
 130 }
 131
 132 #undef DP_STR
 133 #define DP_STR(x) [DP_NAK_ ## x] = #x
 134
 135 static const char *drm_dp_mst_nak_reason_str(u8 nak_reason)
 136 {
 137         static const char * const nak_reason_str[] = {
 138                 DP_STR(WRITE_FAILURE),
 139                 DP_STR(INVALID_READ),
 140                 DP_STR(CRC_FAILURE),
 141                 DP_STR(BAD_PARAM),
 142                 DP_STR(DEFER),
 143                 DP_STR(LINK_FAILURE),
 144                 DP_STR(NO_RESOURCES),
 145                 DP_STR(DPCD_FAIL),
 146                 DP_STR(I2C_NAK),
 147                 DP_STR(ALLOCATE_FAIL),
 148         };
 149
 150         if (nak_reason >= ARRAY_SIZE(nak_reason_str) ||
 151             !nak_reason_str[nak_reason])
 152                 return "unknown";
 153
 154         return nak_reason_str[nak_reason];
 155 }
 156
 157 #undef DP_STR
 158 #define DP_STR(x) [DRM_DP_SIDEBAND_TX_ ## x] = #x
 159
 160 static const char *drm_dp_mst_sideband_tx_state_str(int state)
 161 {
 162         static const char * const sideband_reason_str[] = {
 163                 DP_STR(QUEUED),
 164                 DP_STR(START_SEND),
 165                 DP_STR(SENT),
 166                 DP_STR(RX),
 167                 DP_STR(TIMEOUT),
 168         };
 169
 170         if (state >= ARRAY_SIZE(sideband_reason_str) ||
 171             !sideband_reason_str[state])
 172                 return "unknown";
 173
 174         return sideband_reason_str[state];
 175 }
 176
 177 static int
 178 drm_dp_mst_rad_to_str(const u8 rad[8], u8 lct, char *out, size_t len)
 179 {
 180         int i;
 181         u8 unpacked_rad[16];
 182
 183         for (i = 0; i < lct; i++) {
 184                 if (i % 2)
 185                         unpacked_rad[i] = rad[i / 2] >> 4;
 186                 else
 187                         unpacked_rad[i] = rad[i / 2] & BIT_MASK(4);
 188         }
 189
 190         /* TODO: Eventually add something to printk so we can format the rad
 191          * like this: 1.2.3
 192          */
 193         return snprintf(out, len, "%*phC", lct, unpacked_rad);
 194 }
 195
 196 /* sideband msg handling */
 197 static u8 drm_dp_msg_header_crc4(const uint8_t *data, size_t num_nibbles)
 198 {
 199         u8 bitmask = 0x80;
 200         u8 bitshift = 7;
 201         u8 array_index = 0;
 202         int number_of_bits = num_nibbles * 4;
 203         u8 remainder = 0;
 204
 205         while (number_of_bits != 0) {
 206                 number_of_bits--;
 207                 remainder <<= 1;
 208                 remainder |= (data[array_index] & bitmask) >> bitshift;
 209                 bitmask >>= 1;
 210                 bitshift--;
 211                 if (bitmask == 0) {
 212                         bitmask = 0x80;
 213                         bitshift = 7;
 214                         array_index++;
 215                 }
 216                 if ((remainder & 0x10) == 0x10)
 217                         remainder ^= 0x13;
 218         }
 219
 220         number_of_bits = 4;
 221         while (number_of_bits != 0) {
 222                 number_of_bits--;
 223                 remainder <<= 1;
 224                 if ((remainder & 0x10) != 0)
 225                         remainder ^= 0x13;
 226         }
 227
 228         return remainder;
 229 }
 230
 231 static u8 drm_dp_msg_data_crc4(const uint8_t *data, u8 number_of_bytes)
 232 {
 233         u8 bitmask = 0x80;
 234         u8 bitshift = 7;
 235         u8 array_index = 0;
 236         int number_of_bits = number_of_bytes * 8;
 237         u16 remainder = 0;
 238
 239         while (number_of_bits != 0) {
 240                 number_of_bits--;
 241                 remainder <<= 1;
 242                 remainder |= (data[array_index] & bitmask) >> bitshift;
 243                 bitmask >>= 1;
 244                 bitshift--;
 245                 if (bitmask == 0) {
 246                         bitmask = 0x80;
 247                         bitshift = 7;
 248                         array_index++;
 249                 }
 250                 if ((remainder & 0x100) == 0x100)
 251                         remainder ^= 0xd5;
 252         }
 253
 254         number_of_bits = 8;
 255         while (number_of_bits != 0) {
 256                 number_of_bits--;
 257                 remainder <<= 1;
 258                 if ((remainder & 0x100) != 0)
 259                         remainder ^= 0xd5;
 260         }
 261
 262         return remainder & 0xff;
 263 }
 264 static inline u8 drm_dp_calc_sb_hdr_size(struct drm_dp_sideband_msg_hdr *hdr)
 265 {
 266         u8 size = 3;
 267
 268         size += (hdr->lct / 2);
 269         return size;
 270 }
 271
 272 static void drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
 273                                            u8 *buf, int *len)
 274 {
 275         int idx = 0;
 276         int i;
 277         u8 crc4;
 278
 279         buf[idx++] = ((hdr->lct & 0xf) << 4) | (hdr->lcr & 0xf);
 280         for (i = 0; i < (hdr->lct / 2); i++)
 281                 buf[idx++] = hdr->rad[i];
 282         buf[idx++] = (hdr->broadcast << 7) | (hdr->path_msg << 6) |
 283                 (hdr->msg_len & 0x3f);
 284         buf[idx++] = (hdr->somt << 7) | (hdr->eomt << 6) | (hdr->seqno << 4);
 285
 286         crc4 = drm_dp_msg_header_crc4(buf, (idx * 2) - 1);
 287         buf[idx - 1] |= (crc4 & 0xf);
 288
 289         *len = idx;
 290 }
 291
 292 static bool drm_dp_decode_sideband_msg_hdr(const struct drm_dp_mst_topology_mgr *mgr,
 293                                            struct drm_dp_sideband_msg_hdr *hdr,
 294                                            u8 *buf, int buflen, u8 *hdrlen)
 295 {
 296         u8 crc4;
 297         u8 len;
 298         int i;
 299         u8 idx;
 300
 301         if (buf[0] == 0)
 302                 return false;
 303         len = 3;
 304         len += ((buf[0] & 0xf0) >> 4) / 2;
 305         if (len > buflen)
 306                 return false;
 307         crc4 = drm_dp_msg_header_crc4(buf, (len * 2) - 1);
 308
 309         if ((crc4 & 0xf) != (buf[len - 1] & 0xf)) {
 310                 drm_dbg_kms(mgr->dev, "crc4 mismatch 0x%x 0x%x\n", crc4, buf[len - 1]);
 311                 return false;
 312         }
 313
 314         hdr->lct = (buf[0] & 0xf0) >> 4;
 315         hdr->lcr = (buf[0] & 0xf);
 316         idx = 1;
 317         for (i = 0; i < (hdr->lct / 2); i++)
 318                 hdr->rad[i] = buf[idx++];
 319         hdr->broadcast = (buf[idx] >> 7) & 0x1;
 320         hdr->path_msg = (buf[idx] >> 6) & 0x1;
 321         hdr->msg_len = buf[idx] & 0x3f;
 322         idx++;
 323         hdr->somt = (buf[idx] >> 7) & 0x1;
 324         hdr->eomt = (buf[idx] >> 6) & 0x1;
 325         hdr->seqno = (buf[idx] >> 4) & 0x1;
 326         idx++;
 327         *hdrlen = idx;
 328         return true;
 329 }
 330
 331 void
 332 drm_dp_encode_sideband_req(const struct drm_dp_sideband_msg_req_body *req,
 333                            struct drm_dp_sideband_msg_tx *raw)
 334 {
 335         int idx = 0;
 336         int i;
 337         u8 *buf = raw->msg;
 338
 339         buf[idx++] = req->req_type & 0x7f;
 340
 341         switch (req->req_type) {
 342         case DP_ENUM_PATH_RESOURCES:
 343         case DP_POWER_DOWN_PHY:
 344         case DP_POWER_UP_PHY:
 345                 buf[idx] = (req->u.port_num.port_number & 0xf) << 4;
 346                 idx++;
 347                 break;
 348         case DP_ALLOCATE_PAYLOAD:
 349                 buf[idx] = (req->u.allocate_payload.port_number & 0xf) << 4 |
 350                         (req->u.allocate_payload.number_sdp_streams & 0xf);
 351                 idx++;
 352                 buf[idx] = (req->u.allocate_payload.vcpi & 0x7f);
 353                 idx++;
 354                 buf[idx] = (req->u.allocate_payload.pbn >> 8);
 355                 idx++;
 356                 buf[idx] = (req->u.allocate_payload.pbn & 0xff);
 357                 idx++;
 358                 for (i = 0; i < req->u.allocate_payload.number_sdp_streams / 2; i++) {
 359                         buf[idx] = ((req->u.allocate_payload.sdp_stream_sink[i * 2] & 0xf) << 4) |
 360                                 (req->u.allocate_payload.sdp_stream_sink[i * 2 + 1] & 0xf);
 361                         idx++;
 362                 }
 363                 if (req->u.allocate_payload.number_sdp_streams & 1) {
 364                         i = req->u.allocate_payload.number_sdp_streams - 1;
 365                         buf[idx] = (req->u.allocate_payload.sdp_stream_sink[i] & 0xf) << 4;
 366                         idx++;
 367                 }
 368                 break;
 369         case DP_QUERY_PAYLOAD:
 370                 buf[idx] = (req->u.query_payload.port_number & 0xf) << 4;
 371                 idx++;
 372                 buf[idx] = (req->u.query_payload.vcpi & 0x7f);
 373                 idx++;
 374                 break;
 375         case DP_REMOTE_DPCD_READ:
 376                 buf[idx] = (req->u.dpcd_read.port_number & 0xf) << 4;
 377                 buf[idx] |= ((req->u.dpcd_read.dpcd_address & 0xf0000) >> 16) & 0xf;
 378                 idx++;
 379                 buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff00) >> 8;
 380                 idx++;
 381                 buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff);
 382                 idx++;
 383                 buf[idx] = (req->u.dpcd_read.num_bytes);
 384                 idx++;
 385                 break;
 386
 387         case DP_REMOTE_DPCD_WRITE:
 388                 buf[idx] = (req->u.dpcd_write.port_number & 0xf) << 4;
 389                 buf[idx] |= ((req->u.dpcd_write.dpcd_address & 0xf0000) >> 16) & 0xf;
 390                 idx++;
 391                 buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff00) >> 8;
 392                 idx++;
 393                 buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff);
 394                 idx++;
 395                 buf[idx] = (req->u.dpcd_write.num_bytes);
 396                 idx++;
 397                 memcpy(&buf[idx], req->u.dpcd_write.bytes, req->u.dpcd_write.num_bytes);
 398                 idx += req->u.dpcd_write.num_bytes;
 399                 break;
 400         case DP_REMOTE_I2C_READ:
 401                 buf[idx] = (req->u.i2c_read.port_number & 0xf) << 4;
 402                 buf[idx] |= (req->u.i2c_read.num_transactions & 0x3);
 403                 idx++;
 404                 for (i = 0; i < (req->u.i2c_read.num_transactions & 0x3); i++) {
 405                         buf[idx] = req->u.i2c_read.transactions[i].i2c_dev_id & 0x7f;
 406                         idx++;
 407                         buf[idx] = req->u.i2c_read.transactions[i].num_bytes;
 408                         idx++;
 409                         memcpy(&buf[idx], req->u.i2c_read.transactions[i].bytes, req->u.i2c_read.transactions[i].num_bytes);
 410                         idx += req->u.i2c_read.transactions[i].num_bytes;
 411
 412                         buf[idx] = (req->u.i2c_read.transactions[i].no_stop_bit & 0x1) << 4;
 413                         buf[idx] |= (req->u.i2c_read.transactions[i].i2c_transaction_delay & 0xf);
 414                         idx++;
 415                 }
 416                 buf[idx] = (req->u.i2c_read.read_i2c_device_id) & 0x7f;
 417                 idx++;
 418                 buf[idx] = (req->u.i2c_read.num_bytes_read);
 419                 idx++;
 420                 break;
 421
 422         case DP_REMOTE_I2C_WRITE:
 423                 buf[idx] = (req->u.i2c_write.port_number & 0xf) << 4;
 424                 idx++;
 425                 buf[idx] = (req->u.i2c_write.write_i2c_device_id) & 0x7f;
 426                 idx++;
 427                 buf[idx] = (req->u.i2c_write.num_bytes);
 428                 idx++;
 429                 memcpy(&buf[idx], req->u.i2c_write.bytes, req->u.i2c_write.num_bytes);
 430                 idx += req->u.i2c_write.num_bytes;
 431                 break;
 432         case DP_QUERY_STREAM_ENC_STATUS: {
 433                 const struct drm_dp_query_stream_enc_status *msg;
 434
 435                 msg = &req->u.enc_status;
 436                 buf[idx] = msg->stream_id;
 437                 idx++;
 438                 memcpy(&buf[idx], msg->client_id, sizeof(msg->client_id));
 439                 idx += sizeof(msg->client_id);
 440                 buf[idx] = 0;
 441                 buf[idx] |= FIELD_PREP(GENMASK(1, 0), msg->stream_event);
 442                 buf[idx] |= msg->valid_stream_event ? BIT(2) : 0;
 443                 buf[idx] |= FIELD_PREP(GENMASK(4, 3), msg->stream_behavior);
 444                 buf[idx] |= msg->valid_stream_behavior ? BIT(5) : 0;
 445                 idx++;
 446                 }
 447                 break;
 448         }
 449         raw->cur_len = idx;
 450 }
 451 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_encode_sideband_req);
 452
 453 /* Decode a sideband request we've encoded, mainly used for debugging */
 454 int
 455 drm_dp_decode_sideband_req(const struct drm_dp_sideband_msg_tx *raw,
 456                            struct drm_dp_sideband_msg_req_body *req)
 457 {
 458         const u8 *buf = raw->msg;
 459         int i, idx = 0;
 460
 461         req->req_type = buf[idx++] & 0x7f;
 462         switch (req->req_type) {
 463         case DP_ENUM_PATH_RESOURCES:
 464         case DP_POWER_DOWN_PHY:
 465         case DP_POWER_UP_PHY:
 466                 req->u.port_num.port_number = (buf[idx] >> 4) & 0xf;
 467                 break;
 468         case DP_ALLOCATE_PAYLOAD:
 469                 {
 470                         struct drm_dp_allocate_payload *a =
 471                                 &req->u.allocate_payload;
 472
 473                         a->number_sdp_streams = buf[idx] & 0xf;
 474                         a->port_number = (buf[idx] >> 4) & 0xf;
 475
 476                         WARN_ON(buf[++idx] & 0x80);
 477                         a->vcpi = buf[idx] & 0x7f;
 478
 479                         a->pbn = buf[++idx] << 8;
 480                         a->pbn |= buf[++idx];
 481
 482                         idx++;
 483                         for (i = 0; i < a->number_sdp_streams; i++) {
 484                                 a->sdp_stream_sink[i] =
 485                                         (buf[idx + (i / 2)] >> ((i % 2) ? 0 : 4)) & 0xf;
 486                         }
 487                 }
 488                 break;
 489         case DP_QUERY_PAYLOAD:
 490                 req->u.query_payload.port_number = (buf[idx] >> 4) & 0xf;
 491                 WARN_ON(buf[++idx] & 0x80);
 492                 req->u.query_payload.vcpi = buf[idx] & 0x7f;
 493                 break;
 494         case DP_REMOTE_DPCD_READ:
 495                 {
 496                         struct drm_dp_remote_dpcd_read *r = &req->u.dpcd_read;
 497
 498                         r->port_number = (buf[idx] >> 4) & 0xf;
 499
 500                         r->dpcd_address = (buf[idx] << 16) & 0xf0000;
 501                         r->dpcd_address |= (buf[++idx] << 8) & 0xff00;
 502                         r->dpcd_address |= buf[++idx] & 0xff;
 503
 504                         r->num_bytes = buf[++idx];
 505                 }
 506                 break;
 507         case DP_REMOTE_DPCD_WRITE:
 508                 {
 509                         struct drm_dp_remote_dpcd_write *w =
 510                                 &req->u.dpcd_write;
 511
 512                         w->port_number = (buf[idx] >> 4) & 0xf;
 513
 514                         w->dpcd_address = (buf[idx] << 16) & 0xf0000;
 515                         w->dpcd_address |= (buf[++idx] << 8) & 0xff00;
 516                         w->dpcd_address |= buf[++idx] & 0xff;
 517
 518                         w->num_bytes = buf[++idx];
 519
 520                         w->bytes = kmemdup(&buf[++idx], w->num_bytes,
 521                                            GFP_KERNEL);
 522                         if (!w->bytes)
 523                                 return -ENOMEM;
 524                 }
 525                 break;
 526         case DP_REMOTE_I2C_READ:
 527                 {
 528                         struct drm_dp_remote_i2c_read *r = &req->u.i2c_read;
 529                         struct drm_dp_remote_i2c_read_tx *tx;
 530                         bool failed = false;
 531
 532                         r->num_transactions = buf[idx] & 0x3;
 533                         r->port_number = (buf[idx] >> 4) & 0xf;
 534                         for (i = 0; i < r->num_transactions; i++) {
 535                                 tx = &r->transactions[i];
 536
 537                                 tx->i2c_dev_id = buf[++idx] & 0x7f;
 538                                 tx->num_bytes = buf[++idx];
 539                                 tx->bytes = kmemdup(&buf[++idx],
 540                                                     tx->num_bytes,
 541                                                     GFP_KERNEL);
 542                                 if (!tx->bytes) {
 543                                         failed = true;
 544                                         break;
 545                                 }
 546                                 idx += tx->num_bytes;
 547                                 tx->no_stop_bit = (buf[idx] >> 5) & 0x1;
 548                                 tx->i2c_transaction_delay = buf[idx] & 0xf;
 549                         }
 550
 551                         if (failed) {
 552                                 for (i = 0; i < r->num_transactions; i++) {
 553                                         tx = &r->transactions[i];
 554                                         kfree(tx->bytes);
 555                                 }
 556                                 return -ENOMEM;
 557                         }
 558
 559                         r->read_i2c_device_id = buf[++idx] & 0x7f;
 560                         r->num_bytes_read = buf[++idx];
 561                 }
 562                 break;
 563         case DP_REMOTE_I2C_WRITE:
 564                 {
 565                         struct drm_dp_remote_i2c_write *w = &req->u.i2c_write;
 566
 567                         w->port_number = (buf[idx] >> 4) & 0xf;
 568                         w->write_i2c_device_id = buf[++idx] & 0x7f;
 569                         w->num_bytes = buf[++idx];
 570                         w->bytes = kmemdup(&buf[++idx], w->num_bytes,
 571                                            GFP_KERNEL);
 572                         if (!w->bytes)
 573                                 return -ENOMEM;
 574                 }
 575                 break;
 576         case DP_QUERY_STREAM_ENC_STATUS:
 577                 req->u.enc_status.stream_id = buf[idx++];
 578                 for (i = 0; i < sizeof(req->u.enc_status.client_id); i++)
 579                         req->u.enc_status.client_id[i] = buf[idx++];
 580
 581                 req->u.enc_status.stream_event = FIELD_GET(GENMASK(1, 0),
 582                                                            buf[idx]);
 583                 req->u.enc_status.valid_stream_event = FIELD_GET(BIT(2),
 584                                                                  buf[idx]);
 585                 req->u.enc_status.stream_behavior = FIELD_GET(GENMASK(4, 3),
 586                                                               buf[idx]);
 587                 req->u.enc_status.valid_stream_behavior = FIELD_GET(BIT(5),
 588                                                                     buf[idx]);
 589                 break;
 590         }
 591
 592         return 0;
 593 }
 594 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_decode_sideband_req);
 595
 596 void
 597 drm_dp_dump_sideband_msg_req_body(const struct drm_dp_sideband_msg_req_body *req,
 598                                   int indent, struct drm_printer *printer)
 599 {
 600         int i;
 601
 602 #define P(f, ...) drm_printf_indent(printer, indent, f, ##__VA_ARGS__)
 603         if (req->req_type == DP_LINK_ADDRESS) {
 604                 /* No contents to print */
 605                 P("type=%s\n", drm_dp_mst_req_type_str(req->req_type));
 606                 return;
 607         }
 608
 609         P("type=%s contents:\n", drm_dp_mst_req_type_str(req->req_type));
 610         indent++;
 611
 612         switch (req->req_type) {
 613         case DP_ENUM_PATH_RESOURCES:
 614         case DP_POWER_DOWN_PHY:
 615         case DP_POWER_UP_PHY:
 616                 P("port=%d\n", req->u.port_num.port_number);
 617                 break;
 618         case DP_ALLOCATE_PAYLOAD:
 619                 P("port=%d vcpi=%d pbn=%d sdp_streams=%d %*ph\n",
 620                   req->u.allocate_payload.port_number,
 621                   req->u.allocate_payload.vcpi, req->u.allocate_payload.pbn,
 622                   req->u.allocate_payload.number_sdp_streams,
 623                   req->u.allocate_payload.number_sdp_streams,
 624                   req->u.allocate_payload.sdp_stream_sink);
 625                 break;
 626         case DP_QUERY_PAYLOAD:
 627                 P("port=%d vcpi=%d\n",
 628                   req->u.query_payload.port_number,
 629                   req->u.query_payload.vcpi);
 630                 break;
 631         case DP_REMOTE_DPCD_READ:
 632                 P("port=%d dpcd_addr=%05x len=%d\n",
 633                   req->u.dpcd_read.port_number, req->u.dpcd_read.dpcd_address,
 634                   req->u.dpcd_read.num_bytes);
 635                 break;
 636         case DP_REMOTE_DPCD_WRITE:
 637                 P("port=%d addr=%05x len=%d: %*ph\n",
 638                   req->u.dpcd_write.port_number,
 639                   req->u.dpcd_write.dpcd_address,
 640                   req->u.dpcd_write.num_bytes, req->u.dpcd_write.num_bytes,
 641                   req->u.dpcd_write.bytes);
 642                 break;
 643         case DP_REMOTE_I2C_READ:
 644                 P("port=%d num_tx=%d id=%d size=%d:\n",
 645                   req->u.i2c_read.port_number,
 646                   req->u.i2c_read.num_transactions,
 647                   req->u.i2c_read.read_i2c_device_id,
 648                   req->u.i2c_read.num_bytes_read);
 649
 650                 indent++;
 651                 for (i = 0; i < req->u.i2c_read.num_transactions; i++) {
 652                         const struct drm_dp_remote_i2c_read_tx *rtx =
 653                                 &req->u.i2c_read.transactions[i];
 654
 655                         P("%d: id=%03d size=%03d no_stop_bit=%d tx_delay=%03d: %*ph\n",
 656                           i, rtx->i2c_dev_id, rtx->num_bytes,
 657                           rtx->no_stop_bit, rtx->i2c_transaction_delay,
 658                           rtx->num_bytes, rtx->bytes);
 659                 }
 660                 break;
 661         case DP_REMOTE_I2C_WRITE:
 662                 P("port=%d id=%d size=%d: %*ph\n",
 663                   req->u.i2c_write.port_number,
 664                   req->u.i2c_write.write_i2c_device_id,
 665                   req->u.i2c_write.num_bytes, req->u.i2c_write.num_bytes,
 666                   req->u.i2c_write.bytes);
 667                 break;
 668         case DP_QUERY_STREAM_ENC_STATUS:
 669                 P("stream_id=%u client_id=%*ph stream_event=%x "
 670                   "valid_event=%d stream_behavior=%x valid_behavior=%d",
 671                   req->u.enc_status.stream_id,
 672                   (int)ARRAY_SIZE(req->u.enc_status.client_id),
 673                   req->u.enc_status.client_id, req->u.enc_status.stream_event,
 674                   req->u.enc_status.valid_stream_event,
 675                   req->u.enc_status.stream_behavior,
 676                   req->u.enc_status.valid_stream_behavior);
 677                 break;
 678         default:
 679                 P("???\n");
 680                 break;
 681         }
 682 #undef P
 683 }
 684 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_dump_sideband_msg_req_body);
 685
 686 static inline void
 687 drm_dp_mst_dump_sideband_msg_tx(struct drm_printer *p,
 688                                 const struct drm_dp_sideband_msg_tx *txmsg)
 689 {
 690         struct drm_dp_sideband_msg_req_body req;
 691         char buf[64];
 692         int ret;
 693         int i;
 694
 695         drm_dp_mst_rad_to_str(txmsg->dst->rad, txmsg->dst->lct, buf,
 696                               sizeof(buf));
 697         drm_printf(p, "txmsg cur_offset=%x cur_len=%x seqno=%x state=%s path_msg=%d dst=%s\n",
 698                    txmsg->cur_offset, txmsg->cur_len, txmsg->seqno,
 699                    drm_dp_mst_sideband_tx_state_str(txmsg->state),
 700                    txmsg->path_msg, buf);
 701
 702         ret = drm_dp_decode_sideband_req(txmsg, &req);
 703         if (ret) {
 704                 drm_printf(p, "<failed to decode sideband req: %d>\n", ret);
 705                 return;
 706         }
 707         drm_dp_dump_sideband_msg_req_body(&req, 1, p);
 708
 709         switch (req.req_type) {
 710         case DP_REMOTE_DPCD_WRITE:
 711                 kfree(req.u.dpcd_write.bytes);
 712                 break;
 713         case DP_REMOTE_I2C_READ:
 714                 for (i = 0; i < req.u.i2c_read.num_transactions; i++)
 715                         kfree(req.u.i2c_read.transactions[i].bytes);
 716                 break;
 717         case DP_REMOTE_I2C_WRITE:
 718                 kfree(req.u.i2c_write.bytes);
 719                 break;
 720         }
 721 }
 722
 723 static void drm_dp_crc_sideband_chunk_req(u8 *msg, u8 len)
 724 {
 725         u8 crc4;
 726
 727         crc4 = drm_dp_msg_data_crc4(msg, len);
 728         msg[len] = crc4;
 729 }
 730
 731 static void drm_dp_encode_sideband_reply(struct drm_dp_sideband_msg_reply_body *rep,
 732                                          struct drm_dp_sideband_msg_tx *raw)
 733 {
 734         int idx = 0;
 735         u8 *buf = raw->msg;
 736
 737         buf[idx++] = (rep->reply_type & 0x1) << 7 | (rep->req_type & 0x7f);
 738
 739         raw->cur_len = idx;
 740 }
 741
 742 static int drm_dp_sideband_msg_set_header(struct drm_dp_sideband_msg_rx *msg,
 743                                           struct drm_dp_sideband_msg_hdr *hdr,
 744                                           u8 hdrlen)
 745 {
 746         /*
 747          * ignore out-of-order messages or messages that are part of a
 748          * failed transaction
 749          */
 750         if (!hdr->somt && !msg->have_somt)
 751                 return false;
 752
 753         /* get length contained in this portion */
 754         msg->curchunk_idx = 0;
 755         msg->curchunk_len = hdr->msg_len;
 756         msg->curchunk_hdrlen = hdrlen;
 757
 758         /* we have already gotten an somt - don't bother parsing */
 759         if (hdr->somt && msg->have_somt)
 760                 return false;
 761
 762         if (hdr->somt) {
 763                 memcpy(&msg->initial_hdr, hdr,
 764                        sizeof(struct drm_dp_sideband_msg_hdr));
 765                 msg->have_somt = true;
 766         }
 767         if (hdr->eomt)
 768                 msg->have_eomt = true;
 769
 770         return true;
 771 }
 772
 773 /* this adds a chunk of msg to the builder to get the final msg */
 774 static bool drm_dp_sideband_append_payload(struct drm_dp_sideband_msg_rx *msg,
 775                                            u8 *replybuf, u8 replybuflen)
 776 {
 777         u8 crc4;
 778
 779         memcpy(&msg->chunk[msg->curchunk_idx], replybuf, replybuflen);
 780         msg->curchunk_idx += replybuflen;
 781
 782         if (msg->curchunk_idx >= msg->curchunk_len) {
 783                 /* do CRC */
 784                 crc4 = drm_dp_msg_data_crc4(msg->chunk, msg->curchunk_len - 1);
 785                 if (crc4 != msg->chunk[msg->curchunk_len - 1])
 786                         print_hex_dump(KERN_DEBUG, "wrong crc",
 787                                        DUMP_PREFIX_NONE, 16, 1,
 788                                        msg->chunk,  msg->curchunk_len, false);
 789                 /* copy chunk into bigger msg */
 790                 memcpy(&msg->msg[msg->curlen], msg->chunk, msg->curchunk_len - 1);
 791                 msg->curlen += msg->curchunk_len - 1;
 792         }
 793         return true;
 794 }
 795
 796 static bool drm_dp_sideband_parse_link_address(const struct drm_dp_mst_topology_mgr *mgr,
 797                                                struct drm_dp_sideband_msg_rx *raw,
 798                                                struct drm_dp_sideband_msg_reply_body *repmsg)
 799 {
 800         int idx = 1;
 801         int i;
 802
 803         memcpy(repmsg->u.link_addr.guid, &raw->msg[idx], 16);
 804         idx += 16;
 805         repmsg->u.link_addr.nports = raw->msg[idx] & 0xf;
 806         idx++;
 807         if (idx > raw->curlen)
 808                 goto fail_len;
 809         for (i = 0; i < repmsg->u.link_addr.nports; i++) {
 810                 if (raw->msg[idx] & 0x80)
 811                         repmsg->u.link_addr.ports[i].input_port = 1;
 812
 813                 repmsg->u.link_addr.ports[i].peer_device_type = (raw->msg[idx] >> 4) & 0x7;
 814                 repmsg->u.link_addr.ports[i].port_number = (raw->msg[idx] & 0xf);
 815
 816                 idx++;
 817                 if (idx > raw->curlen)
 818                         goto fail_len;
 819                 repmsg->u.link_addr.ports[i].mcs = (raw->msg[idx] >> 7) & 0x1;
 820                 repmsg->u.link_addr.ports[i].ddps = (raw->msg[idx] >> 6) & 0x1;
 821                 if (repmsg->u.link_addr.ports[i].input_port == 0)
 822                         repmsg->u.link_addr.ports[i].legacy_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
 823                 idx++;
 824                 if (idx > raw->curlen)
 825                         goto fail_len;
 826                 if (repmsg->u.link_addr.ports[i].input_port == 0) {
 827                         repmsg->u.link_addr.ports[i].dpcd_revision = (raw->msg[idx]);
 828                         idx++;
 829                         if (idx > raw->curlen)
 830                                 goto fail_len;
 831                         memcpy(repmsg->u.link_addr.ports[i].peer_guid, &raw->msg[idx], 16);
 832                         idx += 16;
 833                         if (idx > raw->curlen)
 834                                 goto fail_len;
 835                         repmsg->u.link_addr.ports[i].num_sdp_streams = (raw->msg[idx] >> 4) & 0xf;
 836                         repmsg->u.link_addr.ports[i].num_sdp_stream_sinks = (raw->msg[idx] & 0xf);
 837                         idx++;
 838
 839                 }
 840                 if (idx > raw->curlen)
 841                         goto fail_len;
 842         }
 843
 844         return true;
 845 fail_len:
 846         DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
 847         return false;
 848 }
 849
 850 static bool drm_dp_sideband_parse_remote_dpcd_read(struct drm_dp_sideband_msg_rx *raw,
 851                                                    struct drm_dp_sideband_msg_reply_body *repmsg)
 852 {
 853         int idx = 1;
 854
 855         repmsg->u.remote_dpcd_read_ack.port_number = raw->msg[idx] & 0xf;
 856         idx++;
 857         if (idx > raw->curlen)
 858                 goto fail_len;
 859         repmsg->u.remote_dpcd_read_ack.num_bytes = raw->msg[idx];
 860         idx++;
 861         if (idx > raw->curlen)
 862                 goto fail_len;
 863
 864         memcpy(repmsg->u.remote_dpcd_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_dpcd_read_ack.num_bytes);
 865         return true;
 866 fail_len:
 867         DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
 868         return false;
 869 }
 870
 871 static bool drm_dp_sideband_parse_remote_dpcd_write(struct drm_dp_sideband_msg_rx *raw,
 872                                                       struct drm_dp_sideband_msg_reply_body *repmsg)
 873 {
 874         int idx = 1;
 875
 876         repmsg->u.remote_dpcd_write_ack.port_number = raw->msg[idx] & 0xf;
 877         idx++;
 878         if (idx > raw->curlen)
 879                 goto fail_len;
 880         return true;
 881 fail_len:
 882         DRM_DEBUG_KMS("parse length fail %d %d\n", idx, raw->curlen);
 883         return false;
 884 }
 885
 886 static bool drm_dp_sideband_parse_remote_i2c_read_ack(struct drm_dp_sideband_msg_rx *raw,
 887                                                       struct drm_dp_sideband_msg_reply_body *repmsg)
 888 {
 889         int idx = 1;
 890
 891         repmsg->u.remote_i2c_read_ack.port_number = (raw->msg[idx] & 0xf);
 892         idx++;
 893         if (idx > raw->curlen)
 894                 goto fail_len;
 895         repmsg->u.remote_i2c_read_ack.num_bytes = raw->msg[idx];
 896         idx++;
 897         /* TODO check */
 898         memcpy(repmsg->u.remote_i2c_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_i2c_read_ack.num_bytes);
 899         return true;
 900 fail_len:
 901         DRM_DEBUG_KMS("remote i2c reply parse length fail %d %d\n", idx, raw->curlen);
 902         return false;
 903 }
 904
 905 static bool drm_dp_sideband_parse_enum_path_resources_ack(struct drm_dp_sideband_msg_rx *raw,
 906                                                           struct drm_dp_sideband_msg_reply_body *repmsg)
 907 {
 908         int idx = 1;
 909
 910         repmsg->u.path_resources.port_number = (raw->msg[idx] >> 4) & 0xf;
 911         repmsg->u.path_resources.fec_capable = raw->msg[idx] & 0x1;
 912         idx++;
 913         if (idx > raw->curlen)
 914                 goto fail_len;
 915         repmsg->u.path_resources.full_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 916         idx += 2;
 917         if (idx > raw->curlen)
 918                 goto fail_len;
 919         repmsg->u.path_resources.avail_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 920         idx += 2;
 921         if (idx > raw->curlen)
 922                 goto fail_len;
 923         return true;
 924 fail_len:
 925         DRM_DEBUG_KMS("enum resource parse length fail %d %d\n", idx, raw->curlen);
 926         return false;
 927 }
 928
 929 static bool drm_dp_sideband_parse_allocate_payload_ack(struct drm_dp_sideband_msg_rx *raw,
 930                                                           struct drm_dp_sideband_msg_reply_body *repmsg)
 931 {
 932         int idx = 1;
 933
 934         repmsg->u.allocate_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
 935         idx++;
 936         if (idx > raw->curlen)
 937                 goto fail_len;
 938         repmsg->u.allocate_payload.vcpi = raw->msg[idx];
 939         idx++;
 940         if (idx > raw->curlen)
 941                 goto fail_len;
 942         repmsg->u.allocate_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 943         idx += 2;
 944         if (idx > raw->curlen)
 945                 goto fail_len;
 946         return true;
 947 fail_len:
 948         DRM_DEBUG_KMS("allocate payload parse length fail %d %d\n", idx, raw->curlen);
 949         return false;
 950 }
 951
 952 static bool drm_dp_sideband_parse_query_payload_ack(struct drm_dp_sideband_msg_rx *raw,
 953                                                     struct drm_dp_sideband_msg_reply_body *repmsg)
 954 {
 955         int idx = 1;
 956
 957         repmsg->u.query_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
 958         idx++;
 959         if (idx > raw->curlen)
 960                 goto fail_len;
 961         repmsg->u.query_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
 962         idx += 2;
 963         if (idx > raw->curlen)
 964                 goto fail_len;
 965         return true;
 966 fail_len:
 967         DRM_DEBUG_KMS("query payload parse length fail %d %d\n", idx, raw->curlen);
 968         return false;
 969 }
 970
 971 static bool drm_dp_sideband_parse_power_updown_phy_ack(struct drm_dp_sideband_msg_rx *raw,
 972                                                        struct drm_dp_sideband_msg_reply_body *repmsg)
 973 {
 974         int idx = 1;
 975
 976         repmsg->u.port_number.port_number = (raw->msg[idx] >> 4) & 0xf;
 977         idx++;
 978         if (idx > raw->curlen) {
 979                 DRM_DEBUG_KMS("power up/down phy parse length fail %d %d\n",
 980                               idx, raw->curlen);
 981                 return false;
 982         }
 983         return true;
 984 }
 985
 986 static bool
 987 drm_dp_sideband_parse_query_stream_enc_status(
 988                                 struct drm_dp_sideband_msg_rx *raw,
 989                                 struct drm_dp_sideband_msg_reply_body *repmsg)
 990 {
 991         struct drm_dp_query_stream_enc_status_ack_reply *reply;
 992
 993         reply = &repmsg->u.enc_status;
 994
 995         reply->stream_id = raw->msg[3];
 996
 997         reply->reply_signed = raw->msg[2] & BIT(0);
 998
 999         /*
1000          * NOTE: It's my impression from reading the spec that the below parsing
1001          * is correct. However I noticed while testing with an HDCP 1.4 display
1002          * through an HDCP 2.2 hub that only bit 3 was set. In that case, I
1003          * would expect both bits to be set. So keep the parsing following the
1004          * spec, but beware reality might not match the spec (at least for some
1005          * configurations).
1006          */
1007         reply->hdcp_1x_device_present = raw->msg[2] & BIT(4);
1008         reply->hdcp_2x_device_present = raw->msg[2] & BIT(3);
1009
1010         reply->query_capable_device_present = raw->msg[2] & BIT(5);
1011         reply->legacy_device_present = raw->msg[2] & BIT(6);
1012         reply->unauthorizable_device_present = raw->msg[2] & BIT(7);
1013
1014         reply->auth_completed = !!(raw->msg[1] & BIT(3));
1015         reply->encryption_enabled = !!(raw->msg[1] & BIT(4));
1016         reply->repeater_present = !!(raw->msg[1] & BIT(5));
1017         reply->state = (raw->msg[1] & GENMASK(7, 6)) >> 6;
1018
1019         return true;
1020 }
1021
1022 static bool drm_dp_sideband_parse_reply(const struct drm_dp_mst_topology_mgr *mgr,
1023                                         struct drm_dp_sideband_msg_rx *raw,
1024                                         struct drm_dp_sideband_msg_reply_body *msg)
1025 {
1026         memset(msg, 0, sizeof(*msg));
1027         msg->reply_type = (raw->msg[0] & 0x80) >> 7;
1028         msg->req_type = (raw->msg[0] & 0x7f);
1029
1030         if (msg->reply_type == DP_SIDEBAND_REPLY_NAK) {
1031                 memcpy(msg->u.nak.guid, &raw->msg[1], 16);
1032                 msg->u.nak.reason = raw->msg[17];
1033                 msg->u.nak.nak_data = raw->msg[18];
1034                 return false;
1035         }
1036
1037         switch (msg->req_type) {
1038         case DP_LINK_ADDRESS:
1039                 return drm_dp_sideband_parse_link_address(mgr, raw, msg);
1040         case DP_QUERY_PAYLOAD:
1041                 return drm_dp_sideband_parse_query_payload_ack(raw, msg);
1042         case DP_REMOTE_DPCD_READ:
1043                 return drm_dp_sideband_parse_remote_dpcd_read(raw, msg);
1044         case DP_REMOTE_DPCD_WRITE:
1045                 return drm_dp_sideband_parse_remote_dpcd_write(raw, msg);
1046         case DP_REMOTE_I2C_READ:
1047                 return drm_dp_sideband_parse_remote_i2c_read_ack(raw, msg);
1048         case DP_REMOTE_I2C_WRITE:
1049                 return true; /* since there's nothing to parse */
1050         case DP_ENUM_PATH_RESOURCES:
1051                 return drm_dp_sideband_parse_enum_path_resources_ack(raw, msg);
1052         case DP_ALLOCATE_PAYLOAD:
1053                 return drm_dp_sideband_parse_allocate_payload_ack(raw, msg);
1054         case DP_POWER_DOWN_PHY:
1055         case DP_POWER_UP_PHY:
1056                 return drm_dp_sideband_parse_power_updown_phy_ack(raw, msg);
1057         case DP_CLEAR_PAYLOAD_ID_TABLE:
1058                 return true; /* since there's nothing to parse */
1059         case DP_QUERY_STREAM_ENC_STATUS:
1060                 return drm_dp_sideband_parse_query_stream_enc_status(raw, msg);
1061         default:
1062                 drm_err(mgr->dev, "Got unknown reply 0x%02x (%s)\n",
1063                         msg->req_type, drm_dp_mst_req_type_str(msg->req_type));
1064                 return false;
1065         }
1066 }
1067
1068 static bool
1069 drm_dp_sideband_parse_connection_status_notify(const struct drm_dp_mst_topology_mgr *mgr,
1070                                                struct drm_dp_sideband_msg_rx *raw,
1071                                                struct drm_dp_sideband_msg_req_body *msg)
1072 {
1073         int idx = 1;
1074
1075         msg->u.conn_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1076         idx++;
1077         if (idx > raw->curlen)
1078                 goto fail_len;
1079
1080         memcpy(msg->u.conn_stat.guid, &raw->msg[idx], 16);
1081         idx += 16;
1082         if (idx > raw->curlen)
1083                 goto fail_len;
1084
1085         msg->u.conn_stat.legacy_device_plug_status = (raw->msg[idx] >> 6) & 0x1;
1086         msg->u.conn_stat.displayport_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
1087         msg->u.conn_stat.message_capability_status = (raw->msg[idx] >> 4) & 0x1;
1088         msg->u.conn_stat.input_port = (raw->msg[idx] >> 3) & 0x1;
1089         msg->u.conn_stat.peer_device_type = (raw->msg[idx] & 0x7);
1090         idx++;
1091         return true;
1092 fail_len:
1093         drm_dbg_kms(mgr->dev, "connection status reply parse length fail %d %d\n",
1094                     idx, raw->curlen);
1095         return false;
1096 }
1097
1098 static bool drm_dp_sideband_parse_resource_status_notify(const struct drm_dp_mst_topology_mgr *mgr,
1099                                                          struct drm_dp_sideband_msg_rx *raw,
1100                                                          struct drm_dp_sideband_msg_req_body *msg)
1101 {
1102         int idx = 1;
1103
1104         msg->u.resource_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1105         idx++;
1106         if (idx > raw->curlen)
1107                 goto fail_len;
1108
1109         memcpy(msg->u.resource_stat.guid, &raw->msg[idx], 16);
1110         idx += 16;
1111         if (idx > raw->curlen)
1112                 goto fail_len;
1113
1114         msg->u.resource_stat.available_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
1115         idx++;
1116         return true;
1117 fail_len:
1118         drm_dbg_kms(mgr->dev, "resource status reply parse length fail %d %d\n", idx, raw->curlen);
1119         return false;
1120 }
1121
1122 static bool drm_dp_sideband_parse_req(const struct drm_dp_mst_topology_mgr *mgr,
1123                                       struct drm_dp_sideband_msg_rx *raw,
1124                                       struct drm_dp_sideband_msg_req_body *msg)
1125 {
1126         memset(msg, 0, sizeof(*msg));
1127         msg->req_type = (raw->msg[0] & 0x7f);
1128
1129         switch (msg->req_type) {
1130         case DP_CONNECTION_STATUS_NOTIFY:
1131                 return drm_dp_sideband_parse_connection_status_notify(mgr, raw, msg);
1132         case DP_RESOURCE_STATUS_NOTIFY:
1133                 return drm_dp_sideband_parse_resource_status_notify(mgr, raw, msg);
1134         default:
1135                 drm_err(mgr->dev, "Got unknown request 0x%02x (%s)\n",
1136                         msg->req_type, drm_dp_mst_req_type_str(msg->req_type));
1137                 return false;
1138         }
1139 }
1140
1141 static void build_dpcd_write(struct drm_dp_sideband_msg_tx *msg,
1142                              u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
1143 {
1144         struct drm_dp_sideband_msg_req_body req;
1145
1146         req.req_type = DP_REMOTE_DPCD_WRITE;
1147         req.u.dpcd_write.port_number = port_num;
1148         req.u.dpcd_write.dpcd_address = offset;
1149         req.u.dpcd_write.num_bytes = num_bytes;
1150         req.u.dpcd_write.bytes = bytes;
1151         drm_dp_encode_sideband_req(&req, msg);
1152 }
1153
1154 static void build_link_address(struct drm_dp_sideband_msg_tx *msg)
1155 {
1156         struct drm_dp_sideband_msg_req_body req;
1157
1158         req.req_type = DP_LINK_ADDRESS;
1159         drm_dp_encode_sideband_req(&req, msg);
1160 }
1161
1162 static void build_clear_payload_id_table(struct drm_dp_sideband_msg_tx *msg)
1163 {
1164         struct drm_dp_sideband_msg_req_body req;
1165
1166         req.req_type = DP_CLEAR_PAYLOAD_ID_TABLE;
1167         drm_dp_encode_sideband_req(&req, msg);
1168         msg->path_msg = true;
1169 }
1170
1171 static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg,
1172                                      int port_num)
1173 {
1174         struct drm_dp_sideband_msg_req_body req;
1175
1176         req.req_type = DP_ENUM_PATH_RESOURCES;
1177         req.u.port_num.port_number = port_num;
1178         drm_dp_encode_sideband_req(&req, msg);
1179         msg->path_msg = true;
1180         return 0;
1181 }
1182
1183 static void build_allocate_payload(struct drm_dp_sideband_msg_tx *msg,
1184                                    int port_num,
1185                                    u8 vcpi, uint16_t pbn,
1186                                    u8 number_sdp_streams,
1187                                    u8 *sdp_stream_sink)
1188 {
1189         struct drm_dp_sideband_msg_req_body req;
1190
1191         memset(&req, 0, sizeof(req));
1192         req.req_type = DP_ALLOCATE_PAYLOAD;
1193         req.u.allocate_payload.port_number = port_num;
1194         req.u.allocate_payload.vcpi = vcpi;
1195         req.u.allocate_payload.pbn = pbn;
1196         req.u.allocate_payload.number_sdp_streams = number_sdp_streams;
1197         memcpy(req.u.allocate_payload.sdp_stream_sink, sdp_stream_sink,
1198                    number_sdp_streams);
1199         drm_dp_encode_sideband_req(&req, msg);
1200         msg->path_msg = true;
1201 }
1202
1203 static void build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,
1204                                    int port_num, bool power_up)
1205 {
1206         struct drm_dp_sideband_msg_req_body req;
1207
1208         if (power_up)
1209                 req.req_type = DP_POWER_UP_PHY;
1210         else
1211                 req.req_type = DP_POWER_DOWN_PHY;
1212
1213         req.u.port_num.port_number = port_num;
1214         drm_dp_encode_sideband_req(&req, msg);
1215         msg->path_msg = true;
1216 }
1217
1218 static int
1219 build_query_stream_enc_status(struct drm_dp_sideband_msg_tx *msg, u8 stream_id,
1220                               u8 *q_id)
1221 {
1222         struct drm_dp_sideband_msg_req_body req;
1223
1224         req.req_type = DP_QUERY_STREAM_ENC_STATUS;
1225         req.u.enc_status.stream_id = stream_id;
1226         memcpy(req.u.enc_status.client_id, q_id,
1227                sizeof(req.u.enc_status.client_id));
1228         req.u.enc_status.stream_event = 0;
1229         req.u.enc_status.valid_stream_event = false;
1230         req.u.enc_status.stream_behavior = 0;
1231         req.u.enc_status.valid_stream_behavior = false;
1232
1233         drm_dp_encode_sideband_req(&req, msg);
1234         return 0;
1235 }
1236
1237 static int drm_dp_mst_assign_payload_id(struct drm_dp_mst_topology_mgr *mgr,
1238                                         struct drm_dp_vcpi *vcpi)
1239 {
1240         int ret, vcpi_ret;
1241
1242         mutex_lock(&mgr->payload_lock);
1243         ret = find_first_zero_bit(&mgr->payload_mask, mgr->max_payloads + 1);
1244         if (ret > mgr->max_payloads) {
1245                 ret = -EINVAL;
1246                 drm_dbg_kms(mgr->dev, "out of payload ids %d\n", ret);
1247                 goto out_unlock;
1248         }
1249
1250         vcpi_ret = find_first_zero_bit(&mgr->vcpi_mask, mgr->max_payloads + 1);
1251         if (vcpi_ret > mgr->max_payloads) {
1252                 ret = -EINVAL;
1253                 drm_dbg_kms(mgr->dev, "out of vcpi ids %d\n", ret);
1254                 goto out_unlock;
1255         }
1256
1257         set_bit(ret, &mgr->payload_mask);
1258         set_bit(vcpi_ret, &mgr->vcpi_mask);
1259         vcpi->vcpi = vcpi_ret + 1;
1260         mgr->proposed_vcpis[ret - 1] = vcpi;
1261 out_unlock:
1262         mutex_unlock(&mgr->payload_lock);
1263         return ret;
1264 }
1265
1266 static void drm_dp_mst_put_payload_id(struct drm_dp_mst_topology_mgr *mgr,
1267                                       int vcpi)
1268 {
1269         int i;
1270
1271         if (vcpi == 0)
1272                 return;
1273
1274         mutex_lock(&mgr->payload_lock);
1275         drm_dbg_kms(mgr->dev, "putting payload %d\n", vcpi);
1276         clear_bit(vcpi - 1, &mgr->vcpi_mask);
1277
1278         for (i = 0; i < mgr->max_payloads; i++) {
1279                 if (mgr->proposed_vcpis[i] &&
1280                     mgr->proposed_vcpis[i]->vcpi == vcpi) {
1281                         mgr->proposed_vcpis[i] = NULL;
1282                         clear_bit(i + 1, &mgr->payload_mask);
1283                 }
1284         }
1285         mutex_unlock(&mgr->payload_lock);
1286 }
1287
1288 static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr,
1289                               struct drm_dp_sideband_msg_tx *txmsg)
1290 {
1291         unsigned int state;
1292
1293         /*
1294          * All updates to txmsg->state are protected by mgr->qlock, and the two
1295          * cases we check here are terminal states. For those the barriers
1296          * provided by the wake_up/wait_event pair are enough.
1297          */
1298         state = READ_ONCE(txmsg->state);
1299         return (state == DRM_DP_SIDEBAND_TX_RX ||
1300                 state == DRM_DP_SIDEBAND_TX_TIMEOUT);
1301 }
1302
1303 static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb,
1304                                     struct drm_dp_sideband_msg_tx *txmsg)
1305 {
1306         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1307         unsigned long wait_timeout = msecs_to_jiffies(4000);
1308         unsigned long wait_expires = jiffies + wait_timeout;
1309         int ret;
1310
1311         for (;;) {
1312                 /*
1313                  * If the driver provides a way for this, change to
1314                  * poll-waiting for the MST reply interrupt if we didn't receive
1315                  * it for 50 msec. This would cater for cases where the HPD
1316                  * pulse signal got lost somewhere, even though the sink raised
1317                  * the corresponding MST interrupt correctly. One example is the
1318                  * Club 3D CAC-1557 TypeC -> DP adapter which for some reason
1319                  * filters out short pulses with a duration less than ~540 usec.
1320                  *
1321                  * The poll period is 50 msec to avoid missing an interrupt
1322                  * after the sink has cleared it (after a 110msec timeout
1323                  * since it raised the interrupt).
1324                  */
1325                 ret = wait_event_timeout(mgr->tx_waitq,
1326                                          check_txmsg_state(mgr, txmsg),
1327                                          mgr->cbs->poll_hpd_irq ?
1328                                                 msecs_to_jiffies(50) :
1329                                                 wait_timeout);
1330
1331                 if (ret || !mgr->cbs->poll_hpd_irq ||
1332                     time_after(jiffies, wait_expires))
1333                         break;
1334
1335                 mgr->cbs->poll_hpd_irq(mgr);
1336         }
1337
1338         mutex_lock(&mgr->qlock);
1339         if (ret > 0) {
1340                 if (txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT) {
1341                         ret = -EIO;
1342                         goto out;
1343                 }
1344         } else {
1345                 drm_dbg_kms(mgr->dev, "timedout msg send %p %d %d\n",
1346                             txmsg, txmsg->state, txmsg->seqno);
1347
1348                 /* dump some state */
1349                 ret = -EIO;
1350
1351                 /* remove from q */
1352                 if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED ||
1353                     txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND ||
1354                     txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
1355                         list_del(&txmsg->next);
1356         }
1357 out:
1358         if (unlikely(ret == -EIO) && drm_debug_enabled(DRM_UT_DP)) {
1359                 struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1360
1361                 drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
1362         }
1363         mutex_unlock(&mgr->qlock);
1364
1365         drm_dp_mst_kick_tx(mgr);
1366         return ret;
1367 }
1368
1369 static struct drm_dp_mst_branch *drm_dp_add_mst_branch_device(u8 lct, u8 *rad)
1370 {
1371         struct drm_dp_mst_branch *mstb;
1372
1373         mstb = kzalloc(sizeof(*mstb), GFP_KERNEL);
1374         if (!mstb)
1375                 return NULL;
1376
1377         mstb->lct = lct;
1378         if (lct > 1)
1379                 memcpy(mstb->rad, rad, lct / 2);
1380         INIT_LIST_HEAD(&mstb->ports);
1381         kref_init(&mstb->topology_kref);
1382         kref_init(&mstb->malloc_kref);
1383         return mstb;
1384 }
1385
1386 static void drm_dp_free_mst_branch_device(struct kref *kref)
1387 {
1388         struct drm_dp_mst_branch *mstb =
1389                 container_of(kref, struct drm_dp_mst_branch, malloc_kref);
1390
1391         if (mstb->port_parent)
1392                 drm_dp_mst_put_port_malloc(mstb->port_parent);
1393
1394         kfree(mstb);
1395 }
1396
1397 /**
1398  * DOC: Branch device and port refcounting
1399  *
1400  * Topology refcount overview
1401  * ~~~~~~~~~~~~~~~~~~~~~~~~~~
1402  *
1403  * The refcounting schemes for &struct drm_dp_mst_branch and &struct
1404  * drm_dp_mst_port are somewhat unusual. Both ports and branch devices have
1405  * two different kinds of refcounts: topology refcounts, and malloc refcounts.
1406  *
1407  * Topology refcounts are not exposed to drivers, and are handled internally
1408  * by the DP MST helpers. The helpers use them in order to prevent the
1409  * in-memory topology state from being changed in the middle of critical
1410  * operations like changing the internal state of payload allocations. This
1411  * means each branch and port will be considered to be connected to the rest
1412  * of the topology until its topology refcount reaches zero. Additionally,
1413  * for ports this means that their associated &struct drm_connector will stay
1414  * registered with userspace until the port's refcount reaches 0.
1415  *
1416  * Malloc refcount overview
1417  * ~~~~~~~~~~~~~~~~~~~~~~~~
1418  *
1419  * Malloc references are used to keep a &struct drm_dp_mst_port or &struct
1420  * drm_dp_mst_branch allocated even after all of its topology references have
1421  * been dropped, so that the driver or MST helpers can safely access each
1422  * branch's last known state before it was disconnected from the topology.
1423  * When the malloc refcount of a port or branch reaches 0, the memory
1424  * allocation containing the &struct drm_dp_mst_branch or &struct
1425  * drm_dp_mst_port respectively will be freed.
1426  *
1427  * For &struct drm_dp_mst_branch, malloc refcounts are not currently exposed
1428  * to drivers. As of writing this documentation, there are no drivers that
1429  * have a usecase for accessing &struct drm_dp_mst_branch outside of the MST
1430  * helpers. Exposing this API to drivers in a race-free manner would take more
1431  * tweaking of the refcounting scheme, however patches are welcome provided
1432  * there is a legitimate driver usecase for this.
1433  *
1434  * Refcount relationships in a topology
1435  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1436  *
1437  * Let's take a look at why the relationship between topology and malloc
1438  * refcounts is designed the way it is.
1439  *
1440  * .. kernel-figure:: dp-mst/topology-figure-1.dot
1441  *
1442  *    An example of topology and malloc refs in a DP MST topology with two
1443  *    active payloads. Topology refcount increments are indicated by solid
1444  *    lines, and malloc refcount increments are indicated by dashed lines.
1445  *    Each starts from the branch which incremented the refcount, and ends at
1446  *    the branch to which the refcount belongs to, i.e. the arrow points the
1447  *    same way as the C pointers used to reference a structure.
1448  *
1449  * As you can see in the above figure, every branch increments the topology
1450  * refcount of its children, and increments the malloc refcount of its
1451  * parent. Additionally, every payload increments the malloc refcount of its
1452  * assigned port by 1.
1453  *
1454  * So, what would happen if MSTB #3 from the above figure was unplugged from
1455  * the system, but the driver hadn't yet removed payload #2 from port #3? The
1456  * topology would start to look like the figure below.
1457  *
1458  * .. kernel-figure:: dp-mst/topology-figure-2.dot
1459  *
1460  *    Ports and branch devices which have been released from memory are
1461  *    colored grey, and references which have been removed are colored red.
1462  *
1463  * Whenever a port or branch device's topology refcount reaches zero, it will
1464  * decrement the topology refcounts of all its children, the malloc refcount
1465  * of its parent, and finally its own malloc refcount. For MSTB #4 and port
1466  * #4, this means they both have been disconnected from the topology and freed
1467  * from memory. But, because payload #2 is still holding a reference to port
1468  * #3, port #3 is removed from the topology but its &struct drm_dp_mst_port
1469  * is still accessible from memory. This also means port #3 has not yet
1470  * decremented the malloc refcount of MSTB #3, so its &struct
1471  * drm_dp_mst_branch will also stay allocated in memory until port #3's
1472  * malloc refcount reaches 0.
1473  *
1474  * This relationship is necessary because in order to release payload #2, we
1475  * need to be able to figure out the last relative of port #3 that's still
1476  * connected to the topology. In this case, we would travel up the topology as
1477  * shown below.
1478  *
1479  * .. kernel-figure:: dp-mst/topology-figure-3.dot
1480  *
1481  * And finally, remove payload #2 by communicating with port #2 through
1482  * sideband transactions.
1483  */
1484
1485 /**
1486  * drm_dp_mst_get_mstb_malloc() - Increment the malloc refcount of a branch
1487  * device
1488  * @mstb: The &struct drm_dp_mst_branch to increment the malloc refcount of
1489  *
1490  * Increments &drm_dp_mst_branch.malloc_kref. When
1491  * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1492  * will be released and @mstb may no longer be used.
1493  *
1494  * See also: drm_dp_mst_put_mstb_malloc()
1495  */
1496 static void
1497 drm_dp_mst_get_mstb_malloc(struct drm_dp_mst_branch *mstb)
1498 {
1499         kref_get(&mstb->malloc_kref);
1500         drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref));
1501 }
1502
1503 /**
1504  * drm_dp_mst_put_mstb_malloc() - Decrement the malloc refcount of a branch
1505  * device
1506  * @mstb: The &struct drm_dp_mst_branch to decrement the malloc refcount of
1507  *
1508  * Decrements &drm_dp_mst_branch.malloc_kref. When
1509  * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1510  * will be released and @mstb may no longer be used.
1511  *
1512  * See also: drm_dp_mst_get_mstb_malloc()
1513  */
1514 static void
1515 drm_dp_mst_put_mstb_malloc(struct drm_dp_mst_branch *mstb)
1516 {
1517         drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref) - 1);
1518         kref_put(&mstb->malloc_kref, drm_dp_free_mst_branch_device);
1519 }
1520
1521 static void drm_dp_free_mst_port(struct kref *kref)
1522 {
1523         struct drm_dp_mst_port *port =
1524                 container_of(kref, struct drm_dp_mst_port, malloc_kref);
1525
1526         drm_dp_mst_put_mstb_malloc(port->parent);
1527         kfree(port);
1528 }
1529
1530 /**
1531  * drm_dp_mst_get_port_malloc() - Increment the malloc refcount of an MST port
1532  * @port: The &struct drm_dp_mst_port to increment the malloc refcount of
1533  *
1534  * Increments &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1535  * reaches 0, the memory allocation for @port will be released and @port may
1536  * no longer be used.
1537  *
1538  * Because @port could potentially be freed at any time by the DP MST helpers
1539  * if &drm_dp_mst_port.malloc_kref reaches 0, including during a call to this
1540  * function, drivers that which to make use of &struct drm_dp_mst_port should
1541  * ensure that they grab at least one main malloc reference to their MST ports
1542  * in &drm_dp_mst_topology_cbs.add_connector. This callback is called before
1543  * there is any chance for &drm_dp_mst_port.malloc_kref to reach 0.
1544  *
1545  * See also: drm_dp_mst_put_port_malloc()
1546  */
1547 void
1548 drm_dp_mst_get_port_malloc(struct drm_dp_mst_port *port)
1549 {
1550         kref_get(&port->malloc_kref);
1551         drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->malloc_kref));
1552 }
1553 EXPORT_SYMBOL(drm_dp_mst_get_port_malloc);
1554
1555 /**
1556  * drm_dp_mst_put_port_malloc() - Decrement the malloc refcount of an MST port
1557  * @port: The &struct drm_dp_mst_port to decrement the malloc refcount of
1558  *
1559  * Decrements &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1560  * reaches 0, the memory allocation for @port will be released and @port may
1561  * no longer be used.
1562  *
1563  * See also: drm_dp_mst_get_port_malloc()
1564  */
1565 void
1566 drm_dp_mst_put_port_malloc(struct drm_dp_mst_port *port)
1567 {
1568         drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->malloc_kref) - 1);
1569         kref_put(&port->malloc_kref, drm_dp_free_mst_port);
1570 }
1571 EXPORT_SYMBOL(drm_dp_mst_put_port_malloc);
1572
1573 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
1574
1575 #define STACK_DEPTH 8
1576
1577 static noinline void
1578 __topology_ref_save(struct drm_dp_mst_topology_mgr *mgr,
1579                     struct drm_dp_mst_topology_ref_history *history,
1580                     enum drm_dp_mst_topology_ref_type type)
1581 {
1582         struct drm_dp_mst_topology_ref_entry *entry = NULL;
1583         depot_stack_handle_t backtrace;
1584         ulong stack_entries[STACK_DEPTH];
1585         uint n;
1586         int i;
1587
1588         n = stack_trace_save(stack_entries, ARRAY_SIZE(stack_entries), 1);
1589         backtrace = stack_depot_save(stack_entries, n, GFP_KERNEL);
1590         if (!backtrace)
1591                 return;
1592
1593         /* Try to find an existing entry for this backtrace */
1594         for (i = 0; i < history->len; i++) {
1595                 if (history->entries[i].backtrace == backtrace) {
1596                         entry = &history->entries[i];
1597                         break;
1598                 }
1599         }
1600
1601         /* Otherwise add one */
1602         if (!entry) {
1603                 struct drm_dp_mst_topology_ref_entry *new;
1604                 int new_len = history->len + 1;
1605
1606                 new = krealloc(history->entries, sizeof(*new) * new_len,
1607                                GFP_KERNEL);
1608                 if (!new)
1609                         return;
1610
1611                 entry = &new[history->len];
1612                 history->len = new_len;
1613                 history->entries = new;
1614
1615                 entry->backtrace = backtrace;
1616                 entry->type = type;
1617                 entry->count = 0;
1618         }
1619         entry->count++;
1620         entry->ts_nsec = ktime_get_ns();
1621 }
1622
1623 static int
1624 topology_ref_history_cmp(const void *a, const void *b)
1625 {
1626         const struct drm_dp_mst_topology_ref_entry *entry_a = a, *entry_b = b;
1627
1628         if (entry_a->ts_nsec > entry_b->ts_nsec)
1629                 return 1;
1630         else if (entry_a->ts_nsec < entry_b->ts_nsec)
1631                 return -1;
1632         else
1633                 return 0;
1634 }
1635
1636 static inline const char *
1637 topology_ref_type_to_str(enum drm_dp_mst_topology_ref_type type)
1638 {
1639         if (type == DRM_DP_MST_TOPOLOGY_REF_GET)
1640                 return "get";
1641         else
1642                 return "put";
1643 }
1644
1645 static void
1646 __dump_topology_ref_history(struct drm_dp_mst_topology_ref_history *history,
1647                             void *ptr, const char *type_str)
1648 {
1649         struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1650         char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
1651         int i;
1652
1653         if (!buf)
1654                 return;
1655
1656         if (!history->len)
1657                 goto out;
1658
1659         /* First, sort the list so that it goes from oldest to newest
1660          * reference entry
1661          */
1662         sort(history->entries, history->len, sizeof(*history->entries),
1663              topology_ref_history_cmp, NULL);
1664
1665         drm_printf(&p, "%s (%p) topology count reached 0, dumping history:\n",
1666                    type_str, ptr);
1667
1668         for (i = 0; i < history->len; i++) {
1669                 const struct drm_dp_mst_topology_ref_entry *entry =
1670                         &history->entries[i];
1671                 u64 ts_nsec = entry->ts_nsec;
1672                 u32 rem_nsec = do_div(ts_nsec, 1000000000);
1673
1674                 stack_depot_snprint(entry->backtrace, buf, PAGE_SIZE, 4);
1675
1676                 drm_printf(&p, "  %d %ss (last at %5llu.%06u):\n%s",
1677                            entry->count,
1678                            topology_ref_type_to_str(entry->type),
1679                            ts_nsec, rem_nsec / 1000, buf);
1680         }
1681
1682         /* Now free the history, since this is the only time we expose it */
1683         kfree(history->entries);
1684 out:
1685         kfree(buf);
1686 }
1687
1688 static __always_inline void
1689 drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb)
1690 {
1691         __dump_topology_ref_history(&mstb->topology_ref_history, mstb,
1692                                     "MSTB");
1693 }
1694
1695 static __always_inline void
1696 drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port)
1697 {
1698         __dump_topology_ref_history(&port->topology_ref_history, port,
1699                                     "Port");
1700 }
1701
1702 static __always_inline void
1703 save_mstb_topology_ref(struct drm_dp_mst_branch *mstb,
1704                        enum drm_dp_mst_topology_ref_type type)
1705 {
1706         __topology_ref_save(mstb->mgr, &mstb->topology_ref_history, type);
1707 }
1708
1709 static __always_inline void
1710 save_port_topology_ref(struct drm_dp_mst_port *port,
1711                        enum drm_dp_mst_topology_ref_type type)
1712 {
1713         __topology_ref_save(port->mgr, &port->topology_ref_history, type);
1714 }
1715
1716 static inline void
1717 topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr)
1718 {
1719         mutex_lock(&mgr->topology_ref_history_lock);
1720 }
1721
1722 static inline void
1723 topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr)
1724 {
1725         mutex_unlock(&mgr->topology_ref_history_lock);
1726 }
1727 #else
1728 static inline void
1729 topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr) {}
1730 static inline void
1731 topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr) {}
1732 static inline void
1733 drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb) {}
1734 static inline void
1735 drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port) {}
1736 #define save_mstb_topology_ref(mstb, type)
1737 #define save_port_topology_ref(port, type)
1738 #endif
1739
1740 static void drm_dp_destroy_mst_branch_device(struct kref *kref)
1741 {
1742         struct drm_dp_mst_branch *mstb =
1743                 container_of(kref, struct drm_dp_mst_branch, topology_kref);
1744         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1745
1746         drm_dp_mst_dump_mstb_topology_history(mstb);
1747
1748         INIT_LIST_HEAD(&mstb->destroy_next);
1749
1750         /*
1751          * This can get called under mgr->mutex, so we need to perform the
1752          * actual destruction of the mstb in another worker
1753          */
1754         mutex_lock(&mgr->delayed_destroy_lock);
1755         list_add(&mstb->destroy_next, &mgr->destroy_branch_device_list);
1756         mutex_unlock(&mgr->delayed_destroy_lock);
1757         queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1758 }
1759
1760 /**
1761  * drm_dp_mst_topology_try_get_mstb() - Increment the topology refcount of a
1762  * branch device unless it's zero
1763  * @mstb: &struct drm_dp_mst_branch to increment the topology refcount of
1764  *
1765  * Attempts to grab a topology reference to @mstb, if it hasn't yet been
1766  * removed from the topology (e.g. &drm_dp_mst_branch.topology_kref has
1767  * reached 0). Holding a topology reference implies that a malloc reference
1768  * will be held to @mstb as long as the user holds the topology reference.
1769  *
1770  * Care should be taken to ensure that the user has at least one malloc
1771  * reference to @mstb. If you already have a topology reference to @mstb, you
1772  * should use drm_dp_mst_topology_get_mstb() instead.
1773  *
1774  * See also:
1775  * drm_dp_mst_topology_get_mstb()
1776  * drm_dp_mst_topology_put_mstb()
1777  *
1778  * Returns:
1779  * * 1: A topology reference was grabbed successfully
1780  * * 0: @port is no longer in the topology, no reference was grabbed
1781  */
1782 static int __must_check
1783 drm_dp_mst_topology_try_get_mstb(struct drm_dp_mst_branch *mstb)
1784 {
1785         int ret;
1786
1787         topology_ref_history_lock(mstb->mgr);
1788         ret = kref_get_unless_zero(&mstb->topology_kref);
1789         if (ret) {
1790                 drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1791                 save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1792         }
1793
1794         topology_ref_history_unlock(mstb->mgr);
1795
1796         return ret;
1797 }
1798
1799 /**
1800  * drm_dp_mst_topology_get_mstb() - Increment the topology refcount of a
1801  * branch device
1802  * @mstb: The &struct drm_dp_mst_branch to increment the topology refcount of
1803  *
1804  * Increments &drm_dp_mst_branch.topology_refcount without checking whether or
1805  * not it's already reached 0. This is only valid to use in scenarios where
1806  * you are already guaranteed to have at least one active topology reference
1807  * to @mstb. Otherwise, drm_dp_mst_topology_try_get_mstb() must be used.
1808  *
1809  * See also:
1810  * drm_dp_mst_topology_try_get_mstb()
1811  * drm_dp_mst_topology_put_mstb()
1812  */
1813 static void drm_dp_mst_topology_get_mstb(struct drm_dp_mst_branch *mstb)
1814 {
1815         topology_ref_history_lock(mstb->mgr);
1816
1817         save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1818         WARN_ON(kref_read(&mstb->topology_kref) == 0);
1819         kref_get(&mstb->topology_kref);
1820         drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1821
1822         topology_ref_history_unlock(mstb->mgr);
1823 }
1824
1825 /**
1826  * drm_dp_mst_topology_put_mstb() - release a topology reference to a branch
1827  * device
1828  * @mstb: The &struct drm_dp_mst_branch to release the topology reference from
1829  *
1830  * Releases a topology reference from @mstb by decrementing
1831  * &drm_dp_mst_branch.topology_kref.
1832  *
1833  * See also:
1834  * drm_dp_mst_topology_try_get_mstb()
1835  * drm_dp_mst_topology_get_mstb()
1836  */
1837 static void
1838 drm_dp_mst_topology_put_mstb(struct drm_dp_mst_branch *mstb)
1839 {
1840         topology_ref_history_lock(mstb->mgr);
1841
1842         drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref) - 1);
1843         save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_PUT);
1844
1845         topology_ref_history_unlock(mstb->mgr);
1846         kref_put(&mstb->topology_kref, drm_dp_destroy_mst_branch_device);
1847 }
1848
1849 static void drm_dp_destroy_port(struct kref *kref)
1850 {
1851         struct drm_dp_mst_port *port =
1852                 container_of(kref, struct drm_dp_mst_port, topology_kref);
1853         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
1854
1855         drm_dp_mst_dump_port_topology_history(port);
1856
1857         /* There's nothing that needs locking to destroy an input port yet */
1858         if (port->input) {
1859                 drm_dp_mst_put_port_malloc(port);
1860                 return;
1861         }
1862
1863         kfree(port->cached_edid);
1864
1865         /*
1866          * we can't destroy the connector here, as we might be holding the
1867          * mode_config.mutex from an EDID retrieval
1868          */
1869         mutex_lock(&mgr->delayed_destroy_lock);
1870         list_add(&port->next, &mgr->destroy_port_list);
1871         mutex_unlock(&mgr->delayed_destroy_lock);
1872         queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1873 }
1874
1875 /**
1876  * drm_dp_mst_topology_try_get_port() - Increment the topology refcount of a
1877  * port unless it's zero
1878  * @port: &struct drm_dp_mst_port to increment the topology refcount of
1879  *
1880  * Attempts to grab a topology reference to @port, if it hasn't yet been
1881  * removed from the topology (e.g. &drm_dp_mst_port.topology_kref has reached
1882  * 0). Holding a topology reference implies that a malloc reference will be
1883  * held to @port as long as the user holds the topology reference.
1884  *
1885  * Care should be taken to ensure that the user has at least one malloc
1886  * reference to @port. If you already have a topology reference to @port, you
1887  * should use drm_dp_mst_topology_get_port() instead.
1888  *
1889  * See also:
1890  * drm_dp_mst_topology_get_port()
1891  * drm_dp_mst_topology_put_port()
1892  *
1893  * Returns:
1894  * * 1: A topology reference was grabbed successfully
1895  * * 0: @port is no longer in the topology, no reference was grabbed
1896  */
1897 static int __must_check
1898 drm_dp_mst_topology_try_get_port(struct drm_dp_mst_port *port)
1899 {
1900         int ret;
1901
1902         topology_ref_history_lock(port->mgr);
1903         ret = kref_get_unless_zero(&port->topology_kref);
1904         if (ret) {
1905                 drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref));
1906                 save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1907         }
1908
1909         topology_ref_history_unlock(port->mgr);
1910         return ret;
1911 }
1912
1913 /**
1914  * drm_dp_mst_topology_get_port() - Increment the topology refcount of a port
1915  * @port: The &struct drm_dp_mst_port to increment the topology refcount of
1916  *
1917  * Increments &drm_dp_mst_port.topology_refcount without checking whether or
1918  * not it's already reached 0. This is only valid to use in scenarios where
1919  * you are already guaranteed to have at least one active topology reference
1920  * to @port. Otherwise, drm_dp_mst_topology_try_get_port() must be used.
1921  *
1922  * See also:
1923  * drm_dp_mst_topology_try_get_port()
1924  * drm_dp_mst_topology_put_port()
1925  */
1926 static void drm_dp_mst_topology_get_port(struct drm_dp_mst_port *port)
1927 {
1928         topology_ref_history_lock(port->mgr);
1929
1930         WARN_ON(kref_read(&port->topology_kref) == 0);
1931         kref_get(&port->topology_kref);
1932         drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref));
1933         save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1934
1935         topology_ref_history_unlock(port->mgr);
1936 }
1937
1938 /**
1939  * drm_dp_mst_topology_put_port() - release a topology reference to a port
1940  * @port: The &struct drm_dp_mst_port to release the topology reference from
1941  *
1942  * Releases a topology reference from @port by decrementing
1943  * &drm_dp_mst_port.topology_kref.
1944  *
1945  * See also:
1946  * drm_dp_mst_topology_try_get_port()
1947  * drm_dp_mst_topology_get_port()
1948  */
1949 static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port)
1950 {
1951         topology_ref_history_lock(port->mgr);
1952
1953         drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref) - 1);
1954         save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_PUT);
1955
1956         topology_ref_history_unlock(port->mgr);
1957         kref_put(&port->topology_kref, drm_dp_destroy_port);
1958 }
1959
1960 static struct drm_dp_mst_branch *
1961 drm_dp_mst_topology_get_mstb_validated_locked(struct drm_dp_mst_branch *mstb,
1962                                               struct drm_dp_mst_branch *to_find)
1963 {
1964         struct drm_dp_mst_port *port;
1965         struct drm_dp_mst_branch *rmstb;
1966
1967         if (to_find == mstb)
1968                 return mstb;
1969
1970         list_for_each_entry(port, &mstb->ports, next) {
1971                 if (port->mstb) {
1972                         rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1973                             port->mstb, to_find);
1974                         if (rmstb)
1975                                 return rmstb;
1976                 }
1977         }
1978         return NULL;
1979 }
1980
1981 static struct drm_dp_mst_branch *
1982 drm_dp_mst_topology_get_mstb_validated(struct drm_dp_mst_topology_mgr *mgr,
1983                                        struct drm_dp_mst_branch *mstb)
1984 {
1985         struct drm_dp_mst_branch *rmstb = NULL;
1986
1987         mutex_lock(&mgr->lock);
1988         if (mgr->mst_primary) {
1989                 rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1990                     mgr->mst_primary, mstb);
1991
1992                 if (rmstb && !drm_dp_mst_topology_try_get_mstb(rmstb))
1993                         rmstb = NULL;
1994         }
1995         mutex_unlock(&mgr->lock);
1996         return rmstb;
1997 }
1998
1999 static struct drm_dp_mst_port *
2000 drm_dp_mst_topology_get_port_validated_locked(struct drm_dp_mst_branch *mstb,
2001                                               struct drm_dp_mst_port *to_find)
2002 {
2003         struct drm_dp_mst_port *port, *mport;
2004
2005         list_for_each_entry(port, &mstb->ports, next) {
2006                 if (port == to_find)
2007                         return port;
2008
2009                 if (port->mstb) {
2010                         mport = drm_dp_mst_topology_get_port_validated_locked(
2011                             port->mstb, to_find);
2012                         if (mport)
2013                                 return mport;
2014                 }
2015         }
2016         return NULL;
2017 }
2018
2019 static struct drm_dp_mst_port *
2020 drm_dp_mst_topology_get_port_validated(struct drm_dp_mst_topology_mgr *mgr,
2021                                        struct drm_dp_mst_port *port)
2022 {
2023         struct drm_dp_mst_port *rport = NULL;
2024
2025         mutex_lock(&mgr->lock);
2026         if (mgr->mst_primary) {
2027                 rport = drm_dp_mst_topology_get_port_validated_locked(
2028                     mgr->mst_primary, port);
2029
2030                 if (rport && !drm_dp_mst_topology_try_get_port(rport))
2031                         rport = NULL;
2032         }
2033         mutex_unlock(&mgr->lock);
2034         return rport;
2035 }
2036
2037 static struct drm_dp_mst_port *drm_dp_get_port(struct drm_dp_mst_branch *mstb, u8 port_num)
2038 {
2039         struct drm_dp_mst_port *port;
2040         int ret;
2041
2042         list_for_each_entry(port, &mstb->ports, next) {
2043                 if (port->port_num == port_num) {
2044                         ret = drm_dp_mst_topology_try_get_port(port);
2045                         return ret ? port : NULL;
2046                 }
2047         }
2048
2049         return NULL;
2050 }
2051
2052 /*
2053  * calculate a new RAD for this MST branch device
2054  * if parent has an LCT of 2 then it has 1 nibble of RAD,
2055  * if parent has an LCT of 3 then it has 2 nibbles of RAD,
2056  */
2057 static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port,
2058                                  u8 *rad)
2059 {
2060         int parent_lct = port->parent->lct;
2061         int shift = 4;
2062         int idx = (parent_lct - 1) / 2;
2063
2064         if (parent_lct > 1) {
2065                 memcpy(rad, port->parent->rad, idx + 1);
2066                 shift = (parent_lct % 2) ? 4 : 0;
2067         } else
2068                 rad[0] = 0;
2069
2070         rad[idx] |= port->port_num << shift;
2071         return parent_lct + 1;
2072 }
2073
2074 static bool drm_dp_mst_is_end_device(u8 pdt, bool mcs)
2075 {
2076         switch (pdt) {
2077         case DP_PEER_DEVICE_DP_LEGACY_CONV:
2078         case DP_PEER_DEVICE_SST_SINK:
2079                 return true;
2080         case DP_PEER_DEVICE_MST_BRANCHING:
2081                 /* For sst branch device */
2082                 if (!mcs)
2083                         return true;
2084
2085                 return false;
2086         }
2087         return true;
2088 }
2089
2090 static int
2091 drm_dp_port_set_pdt(struct drm_dp_mst_port *port, u8 new_pdt,
2092                     bool new_mcs)
2093 {
2094         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2095         struct drm_dp_mst_branch *mstb;
2096         u8 rad[8], lct;
2097         int ret = 0;
2098
2099         if (port->pdt == new_pdt && port->mcs == new_mcs)
2100                 return 0;
2101
2102         /* Teardown the old pdt, if there is one */
2103         if (port->pdt != DP_PEER_DEVICE_NONE) {
2104                 if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2105                         /*
2106                          * If the new PDT would also have an i2c bus,
2107                          * don't bother with reregistering it
2108                          */
2109                         if (new_pdt != DP_PEER_DEVICE_NONE &&
2110                             drm_dp_mst_is_end_device(new_pdt, new_mcs)) {
2111                                 port->pdt = new_pdt;
2112                                 port->mcs = new_mcs;
2113                                 return 0;
2114                         }
2115
2116                         /* remove i2c over sideband */
2117                         drm_dp_mst_unregister_i2c_bus(port);
2118                 } else {
2119                         mutex_lock(&mgr->lock);
2120                         drm_dp_mst_topology_put_mstb(port->mstb);
2121                         port->mstb = NULL;
2122                         mutex_unlock(&mgr->lock);
2123                 }
2124         }
2125
2126         port->pdt = new_pdt;
2127         port->mcs = new_mcs;
2128
2129         if (port->pdt != DP_PEER_DEVICE_NONE) {
2130                 if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2131                         /* add i2c over sideband */
2132                         ret = drm_dp_mst_register_i2c_bus(port);
2133                 } else {
2134                         lct = drm_dp_calculate_rad(port, rad);
2135                         mstb = drm_dp_add_mst_branch_device(lct, rad);
2136                         if (!mstb) {
2137                                 ret = -ENOMEM;
2138                                 drm_err(mgr->dev, "Failed to create MSTB for port %p", port);
2139                                 goto out;
2140                         }
2141
2142                         mutex_lock(&mgr->lock);
2143                         port->mstb = mstb;
2144                         mstb->mgr = port->mgr;
2145                         mstb->port_parent = port;
2146
2147                         /*
2148                          * Make sure this port's memory allocation stays
2149                          * around until its child MSTB releases it
2150                          */
2151                         drm_dp_mst_get_port_malloc(port);
2152                         mutex_unlock(&mgr->lock);
2153
2154                         /* And make sure we send a link address for this */
2155                         ret = 1;
2156                 }
2157         }
2158
2159 out:
2160         if (ret < 0)
2161                 port->pdt = DP_PEER_DEVICE_NONE;
2162         return ret;
2163 }
2164
2165 /**
2166  * drm_dp_mst_dpcd_read() - read a series of bytes from the DPCD via sideband
2167  * @aux: Fake sideband AUX CH
2168  * @offset: address of the (first) register to read
2169  * @buffer: buffer to store the register values
2170  * @size: number of bytes in @buffer
2171  *
2172  * Performs the same functionality for remote devices via
2173  * sideband messaging as drm_dp_dpcd_read() does for local
2174  * devices via actual AUX CH.
2175  *
2176  * Return: Number of bytes read, or negative error code on failure.
2177  */
2178 ssize_t drm_dp_mst_dpcd_read(struct drm_dp_aux *aux,
2179                              unsigned int offset, void *buffer, size_t size)
2180 {
2181         struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2182                                                     aux);
2183
2184         return drm_dp_send_dpcd_read(port->mgr, port,
2185                                      offset, size, buffer);
2186 }
2187
2188 /**
2189  * drm_dp_mst_dpcd_write() - write a series of bytes to the DPCD via sideband
2190  * @aux: Fake sideband AUX CH
2191  * @offset: address of the (first) register to write
2192  * @buffer: buffer containing the values to write
2193  * @size: number of bytes in @buffer
2194  *
2195  * Performs the same functionality for remote devices via
2196  * sideband messaging as drm_dp_dpcd_write() does for local
2197  * devices via actual AUX CH.
2198  *
2199  * Return: number of bytes written on success, negative error code on failure.
2200  */
2201 ssize_t drm_dp_mst_dpcd_write(struct drm_dp_aux *aux,
2202                               unsigned int offset, void *buffer, size_t size)
2203 {
2204         struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2205                                                     aux);
2206
2207         return drm_dp_send_dpcd_write(port->mgr, port,
2208                                       offset, size, buffer);
2209 }
2210
2211 static int drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid)
2212 {
2213         int ret = 0;
2214
2215         memcpy(mstb->guid, guid, 16);
2216
2217         if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) {
2218                 if (mstb->port_parent) {
2219                         ret = drm_dp_send_dpcd_write(mstb->mgr,
2220                                                      mstb->port_parent,
2221                                                      DP_GUID, 16, mstb->guid);
2222                 } else {
2223                         ret = drm_dp_dpcd_write(mstb->mgr->aux,
2224                                                 DP_GUID, mstb->guid, 16);
2225                 }
2226         }
2227
2228         if (ret < 16 && ret > 0)
2229                 return -EPROTO;
2230
2231         return ret == 16 ? 0 : ret;
2232 }
2233
2234 static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
2235                                 int pnum,
2236                                 char *proppath,
2237                                 size_t proppath_size)
2238 {
2239         int i;
2240         char temp[8];
2241
2242         snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id);
2243         for (i = 0; i < (mstb->lct - 1); i++) {
2244                 int shift = (i % 2) ? 0 : 4;
2245                 int port_num = (mstb->rad[i / 2] >> shift) & 0xf;
2246
2247                 snprintf(temp, sizeof(temp), "-%d", port_num);
2248                 strlcat(proppath, temp, proppath_size);
2249         }
2250         snprintf(temp, sizeof(temp), "-%d", pnum);
2251         strlcat(proppath, temp, proppath_size);
2252 }
2253
2254 /**
2255  * drm_dp_mst_connector_late_register() - Late MST connector registration
2256  * @connector: The MST connector
2257  * @port: The MST port for this connector
2258  *
2259  * Helper to register the remote aux device for this MST port. Drivers should
2260  * call this from their mst connector's late_register hook to enable MST aux
2261  * devices.
2262  *
2263  * Return: 0 on success, negative error code on failure.
2264  */
2265 int drm_dp_mst_connector_late_register(struct drm_connector *connector,
2266                                        struct drm_dp_mst_port *port)
2267 {
2268         drm_dbg_kms(port->mgr->dev, "registering %s remote bus for %s\n",
2269                     port->aux.name, connector->kdev->kobj.name);
2270
2271         port->aux.dev = connector->kdev;
2272         return drm_dp_aux_register_devnode(&port->aux);
2273 }
2274 EXPORT_SYMBOL(drm_dp_mst_connector_late_register);
2275
2276 /**
2277  * drm_dp_mst_connector_early_unregister() - Early MST connector unregistration
2278  * @connector: The MST connector
2279  * @port: The MST port for this connector
2280  *
2281  * Helper to unregister the remote aux device for this MST port, registered by
2282  * drm_dp_mst_connector_late_register(). Drivers should call this from their mst
2283  * connector's early_unregister hook.
2284  */
2285 void drm_dp_mst_connector_early_unregister(struct drm_connector *connector,
2286                                            struct drm_dp_mst_port *port)
2287 {
2288         drm_dbg_kms(port->mgr->dev, "unregistering %s remote bus for %s\n",
2289                     port->aux.name, connector->kdev->kobj.name);
2290         drm_dp_aux_unregister_devnode(&port->aux);
2291 }
2292 EXPORT_SYMBOL(drm_dp_mst_connector_early_unregister);
2293
2294 static void
2295 drm_dp_mst_port_add_connector(struct drm_dp_mst_branch *mstb,
2296                               struct drm_dp_mst_port *port)
2297 {
2298         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2299         char proppath[255];
2300         int ret;
2301
2302         build_mst_prop_path(mstb, port->port_num, proppath, sizeof(proppath));
2303         port->connector = mgr->cbs->add_connector(mgr, port, proppath);
2304         if (!port->connector) {
2305                 ret = -ENOMEM;
2306                 goto error;
2307         }
2308
2309         if (port->pdt != DP_PEER_DEVICE_NONE &&
2310             drm_dp_mst_is_end_device(port->pdt, port->mcs) &&
2311             port->port_num >= DP_MST_LOGICAL_PORT_0)
2312                 port->cached_edid = drm_get_edid(port->connector,
2313                                                  &port->aux.ddc);
2314
2315         drm_connector_register(port->connector);
2316         return;
2317
2318 error:
2319         drm_err(mgr->dev, "Failed to create connector for port %p: %d\n", port, ret);
2320 }
2321
2322 /*
2323  * Drop a topology reference, and unlink the port from the in-memory topology
2324  * layout
2325  */
2326 static void
2327 drm_dp_mst_topology_unlink_port(struct drm_dp_mst_topology_mgr *mgr,
2328                                 struct drm_dp_mst_port *port)
2329 {
2330         mutex_lock(&mgr->lock);
2331         port->parent->num_ports--;
2332         list_del(&port->next);
2333         mutex_unlock(&mgr->lock);
2334         drm_dp_mst_topology_put_port(port);
2335 }
2336
2337 static struct drm_dp_mst_port *
2338 drm_dp_mst_add_port(struct drm_device *dev,
2339                     struct drm_dp_mst_topology_mgr *mgr,
2340                     struct drm_dp_mst_branch *mstb, u8 port_number)
2341 {
2342         struct drm_dp_mst_port *port = kzalloc(sizeof(*port), GFP_KERNEL);
2343
2344         if (!port)
2345                 return NULL;
2346
2347         kref_init(&port->topology_kref);
2348         kref_init(&port->malloc_kref);
2349         port->parent = mstb;
2350         port->port_num = port_number;
2351         port->mgr = mgr;
2352         port->aux.name = "DPMST";
2353         port->aux.dev = dev->dev;
2354         port->aux.is_remote = true;
2355
2356         /* initialize the MST downstream port's AUX crc work queue */
2357         port->aux.drm_dev = dev;
2358         drm_dp_remote_aux_init(&port->aux);
2359
2360         /*
2361          * Make sure the memory allocation for our parent branch stays
2362          * around until our own memory allocation is released
2363          */
2364         drm_dp_mst_get_mstb_malloc(mstb);
2365
2366         return port;
2367 }
2368
2369 static int
2370 drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb,
2371                                     struct drm_device *dev,
2372                                     struct drm_dp_link_addr_reply_port *port_msg)
2373 {
2374         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2375         struct drm_dp_mst_port *port;
2376         int old_ddps = 0, ret;
2377         u8 new_pdt = DP_PEER_DEVICE_NONE;
2378         bool new_mcs = 0;
2379         bool created = false, send_link_addr = false, changed = false;
2380
2381         port = drm_dp_get_port(mstb, port_msg->port_number);
2382         if (!port) {
2383                 port = drm_dp_mst_add_port(dev, mgr, mstb,
2384                                            port_msg->port_number);
2385                 if (!port)
2386                         return -ENOMEM;
2387                 created = true;
2388                 changed = true;
2389         } else if (!port->input && port_msg->input_port && port->connector) {
2390                 /* Since port->connector can't be changed here, we create a
2391                  * new port if input_port changes from 0 to 1
2392                  */
2393                 drm_dp_mst_topology_unlink_port(mgr, port);
2394                 drm_dp_mst_topology_put_port(port);
2395                 port = drm_dp_mst_add_port(dev, mgr, mstb,
2396                                            port_msg->port_number);
2397                 if (!port)
2398                         return -ENOMEM;
2399                 changed = true;
2400                 created = true;
2401         } else if (port->input && !port_msg->input_port) {
2402                 changed = true;
2403         } else if (port->connector) {
2404                 /* We're updating a port that's exposed to userspace, so do it
2405                  * under lock
2406                  */
2407                 drm_modeset_lock(&mgr->base.lock, NULL);
2408
2409                 old_ddps = port->ddps;
2410                 changed = port->ddps != port_msg->ddps ||
2411                         (port->ddps &&
2412                          (port->ldps != port_msg->legacy_device_plug_status ||
2413                           port->dpcd_rev != port_msg->dpcd_revision ||
2414                           port->mcs != port_msg->mcs ||
2415                           port->pdt != port_msg->peer_device_type ||
2416                           port->num_sdp_stream_sinks !=
2417                           port_msg->num_sdp_stream_sinks));
2418         }
2419
2420         port->input = port_msg->input_port;
2421         if (!port->input)
2422                 new_pdt = port_msg->peer_device_type;
2423         new_mcs = port_msg->mcs;
2424         port->ddps = port_msg->ddps;
2425         port->ldps = port_msg->legacy_device_plug_status;
2426         port->dpcd_rev = port_msg->dpcd_revision;
2427         port->num_sdp_streams = port_msg->num_sdp_streams;
2428         port->num_sdp_stream_sinks = port_msg->num_sdp_stream_sinks;
2429
2430         /* manage mstb port lists with mgr lock - take a reference
2431            for this list */
2432         if (created) {
2433                 mutex_lock(&mgr->lock);
2434                 drm_dp_mst_topology_get_port(port);
2435                 list_add(&port->next, &mstb->ports);
2436                 mstb->num_ports++;
2437                 mutex_unlock(&mgr->lock);
2438         }
2439
2440         /*
2441          * Reprobe PBN caps on both hotplug, and when re-probing the link
2442          * for our parent mstb
2443          */
2444         if (old_ddps != port->ddps || !created) {
2445                 if (port->ddps && !port->input) {
2446                         ret = drm_dp_send_enum_path_resources(mgr, mstb,
2447                                                               port);
2448                         if (ret == 1)
2449                                 changed = true;
2450                 } else {
2451                         port->full_pbn = 0;
2452                 }
2453         }
2454
2455         ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2456         if (ret == 1) {
2457                 send_link_addr = true;
2458         } else if (ret < 0) {
2459                 drm_err(dev, "Failed to change PDT on port %p: %d\n", port, ret);
2460                 goto fail;
2461         }
2462
2463         /*
2464          * If this port wasn't just created, then we're reprobing because
2465          * we're coming out of suspend. In this case, always resend the link
2466          * address if there's an MSTB on this port
2467          */
2468         if (!created && port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
2469             port->mcs)
2470                 send_link_addr = true;
2471
2472         if (port->connector)
2473                 drm_modeset_unlock(&mgr->base.lock);
2474         else if (!port->input)
2475                 drm_dp_mst_port_add_connector(mstb, port);
2476
2477         if (send_link_addr && port->mstb) {
2478                 ret = drm_dp_send_link_address(mgr, port->mstb);
2479                 if (ret == 1) /* MSTB below us changed */
2480                         changed = true;
2481                 else if (ret < 0)
2482                         goto fail_put;
2483         }
2484
2485         /* put reference to this port */
2486         drm_dp_mst_topology_put_port(port);
2487         return changed;
2488
2489 fail:
2490         drm_dp_mst_topology_unlink_port(mgr, port);
2491         if (port->connector)
2492                 drm_modeset_unlock(&mgr->base.lock);
2493 fail_put:
2494         drm_dp_mst_topology_put_port(port);
2495         return ret;
2496 }
2497
2498 static void
2499 drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
2500                             struct drm_dp_connection_status_notify *conn_stat)
2501 {
2502         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2503         struct drm_dp_mst_port *port;
2504         int old_ddps, ret;
2505         u8 new_pdt;
2506         bool new_mcs;
2507         bool dowork = false, create_connector = false;
2508
2509         port = drm_dp_get_port(mstb, conn_stat->port_number);
2510         if (!port)
2511                 return;
2512
2513         if (port->connector) {
2514                 if (!port->input && conn_stat->input_port) {
2515                         /*
2516                          * We can't remove a connector from an already exposed
2517                          * port, so just throw the port out and make sure we
2518                          * reprobe the link address of it's parent MSTB
2519                          */
2520                         drm_dp_mst_topology_unlink_port(mgr, port);
2521                         mstb->link_address_sent = false;
2522                         dowork = true;
2523                         goto out;
2524                 }
2525
2526                 /* Locking is only needed if the port's exposed to userspace */
2527                 drm_modeset_lock(&mgr->base.lock, NULL);
2528         } else if (port->input && !conn_stat->input_port) {
2529                 create_connector = true;
2530                 /* Reprobe link address so we get num_sdp_streams */
2531                 mstb->link_address_sent = false;
2532                 dowork = true;
2533         }
2534
2535         old_ddps = port->ddps;
2536         port->input = conn_stat->input_port;
2537         port->ldps = conn_stat->legacy_device_plug_status;
2538         port->ddps = conn_stat->displayport_device_plug_status;
2539
2540         if (old_ddps != port->ddps) {
2541                 if (port->ddps && !port->input)
2542                         drm_dp_send_enum_path_resources(mgr, mstb, port);
2543                 else
2544                         port->full_pbn = 0;
2545         }
2546
2547         new_pdt = port->input ? DP_PEER_DEVICE_NONE : conn_stat->peer_device_type;
2548         new_mcs = conn_stat->message_capability_status;
2549         ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2550         if (ret == 1) {
2551                 dowork = true;
2552         } else if (ret < 0) {
2553                 drm_err(mgr->dev, "Failed to change PDT for port %p: %d\n", port, ret);
2554                 dowork = false;
2555         }
2556
2557         if (port->connector)
2558                 drm_modeset_unlock(&mgr->base.lock);
2559         else if (create_connector)
2560                 drm_dp_mst_port_add_connector(mstb, port);
2561
2562 out:
2563         drm_dp_mst_topology_put_port(port);
2564         if (dowork)
2565                 queue_work(system_long_wq, &mstb->mgr->work);
2566 }
2567
2568 static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr *mgr,
2569                                                                u8 lct, u8 *rad)
2570 {
2571         struct drm_dp_mst_branch *mstb;
2572         struct drm_dp_mst_port *port;
2573         int i, ret;
2574         /* find the port by iterating down */
2575
2576         mutex_lock(&mgr->lock);
2577         mstb = mgr->mst_primary;
2578
2579         if (!mstb)
2580                 goto out;
2581
2582         for (i = 0; i < lct - 1; i++) {
2583                 int shift = (i % 2) ? 0 : 4;
2584                 int port_num = (rad[i / 2] >> shift) & 0xf;
2585
2586                 list_for_each_entry(port, &mstb->ports, next) {
2587                         if (port->port_num == port_num) {
2588                                 mstb = port->mstb;
2589                                 if (!mstb) {
2590                                         drm_err(mgr->dev,
2591                                                 "failed to lookup MSTB with lct %d, rad %02x\n",
2592                                                 lct, rad[0]);
2593                                         goto out;
2594                                 }
2595
2596                                 break;
2597                         }
2598                 }
2599         }
2600         ret = drm_dp_mst_topology_try_get_mstb(mstb);
2601         if (!ret)
2602                 mstb = NULL;
2603 out:
2604         mutex_unlock(&mgr->lock);
2605         return mstb;
2606 }
2607
2608 static struct drm_dp_mst_branch *get_mst_branch_device_by_guid_helper(
2609         struct drm_dp_mst_branch *mstb,
2610         const uint8_t *guid)
2611 {
2612         struct drm_dp_mst_branch *found_mstb;
2613         struct drm_dp_mst_port *port;
2614
2615         if (memcmp(mstb->guid, guid, 16) == 0)
2616                 return mstb;
2617
2618
2619         list_for_each_entry(port, &mstb->ports, next) {
2620                 if (!port->mstb)
2621                         continue;
2622
2623                 found_mstb = get_mst_branch_device_by_guid_helper(port->mstb, guid);
2624
2625                 if (found_mstb)
2626                         return found_mstb;
2627         }
2628
2629         return NULL;
2630 }
2631
2632 static struct drm_dp_mst_branch *
2633 drm_dp_get_mst_branch_device_by_guid(struct drm_dp_mst_topology_mgr *mgr,
2634                                      const uint8_t *guid)
2635 {
2636         struct drm_dp_mst_branch *mstb;
2637         int ret;
2638
2639         /* find the port by iterating down */
2640         mutex_lock(&mgr->lock);
2641
2642         mstb = get_mst_branch_device_by_guid_helper(mgr->mst_primary, guid);
2643         if (mstb) {
2644                 ret = drm_dp_mst_topology_try_get_mstb(mstb);
2645                 if (!ret)
2646                         mstb = NULL;
2647         }
2648
2649         mutex_unlock(&mgr->lock);
2650         return mstb;
2651 }
2652
2653 static int drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2654                                                struct drm_dp_mst_branch *mstb)
2655 {
2656         struct drm_dp_mst_port *port;
2657         int ret;
2658         bool changed = false;
2659
2660         if (!mstb->link_address_sent) {
2661                 ret = drm_dp_send_link_address(mgr, mstb);
2662                 if (ret == 1)
2663                         changed = true;
2664                 else if (ret < 0)
2665                         return ret;
2666         }
2667
2668         list_for_each_entry(port, &mstb->ports, next) {
2669                 struct drm_dp_mst_branch *mstb_child = NULL;
2670
2671                 if (port->input || !port->ddps)
2672                         continue;
2673
2674                 if (port->mstb)
2675                         mstb_child = drm_dp_mst_topology_get_mstb_validated(
2676                             mgr, port->mstb);
2677
2678                 if (mstb_child) {
2679                         ret = drm_dp_check_and_send_link_address(mgr,
2680                                                                  mstb_child);
2681                         drm_dp_mst_topology_put_mstb(mstb_child);
2682                         if (ret == 1)
2683                                 changed = true;
2684                         else if (ret < 0)
2685                                 return ret;
2686                 }
2687         }
2688
2689         return changed;
2690 }
2691
2692 static void drm_dp_mst_link_probe_work(struct work_struct *work)
2693 {
2694         struct drm_dp_mst_topology_mgr *mgr =
2695                 container_of(work, struct drm_dp_mst_topology_mgr, work);
2696         struct drm_device *dev = mgr->dev;
2697         struct drm_dp_mst_branch *mstb;
2698         int ret;
2699         bool clear_payload_id_table;
2700
2701         mutex_lock(&mgr->probe_lock);
2702
2703         mutex_lock(&mgr->lock);
2704         clear_payload_id_table = !mgr->payload_id_table_cleared;
2705         mgr->payload_id_table_cleared = true;
2706
2707         mstb = mgr->mst_primary;
2708         if (mstb) {
2709                 ret = drm_dp_mst_topology_try_get_mstb(mstb);
2710                 if (!ret)
2711                         mstb = NULL;
2712         }
2713         mutex_unlock(&mgr->lock);
2714         if (!mstb) {
2715                 mutex_unlock(&mgr->probe_lock);
2716                 return;
2717         }
2718
2719         /*
2720          * Certain branch devices seem to incorrectly report an available_pbn
2721          * of 0 on downstream sinks, even after clearing the
2722          * DP_PAYLOAD_ALLOCATE_* registers in
2723          * drm_dp_mst_topology_mgr_set_mst(). Namely, the CableMatters USB-C
2724          * 2x DP hub. Sending a CLEAR_PAYLOAD_ID_TABLE message seems to make
2725          * things work again.
2726          */
2727         if (clear_payload_id_table) {
2728                 drm_dbg_kms(dev, "Clearing payload ID table\n");
2729                 drm_dp_send_clear_payload_id_table(mgr, mstb);
2730         }
2731
2732         ret = drm_dp_check_and_send_link_address(mgr, mstb);
2733         drm_dp_mst_topology_put_mstb(mstb);
2734
2735         mutex_unlock(&mgr->probe_lock);
2736         if (ret > 0)
2737                 drm_kms_helper_hotplug_event(dev);
2738 }
2739
2740 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
2741                                  u8 *guid)
2742 {
2743         u64 salt;
2744
2745         if (memchr_inv(guid, 0, 16))
2746                 return true;
2747
2748         salt = get_jiffies_64();
2749
2750         memcpy(&guid[0], &salt, sizeof(u64));
2751         memcpy(&guid[8], &salt, sizeof(u64));
2752
2753         return false;
2754 }
2755
2756 static void build_dpcd_read(struct drm_dp_sideband_msg_tx *msg,
2757                             u8 port_num, u32 offset, u8 num_bytes)
2758 {
2759         struct drm_dp_sideband_msg_req_body req;
2760
2761         req.req_type = DP_REMOTE_DPCD_READ;
2762         req.u.dpcd_read.port_number = port_num;
2763         req.u.dpcd_read.dpcd_address = offset;
2764         req.u.dpcd_read.num_bytes = num_bytes;
2765         drm_dp_encode_sideband_req(&req, msg);
2766 }
2767
2768 static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr,
2769                                     bool up, u8 *msg, int len)
2770 {
2771         int ret;
2772         int regbase = up ? DP_SIDEBAND_MSG_UP_REP_BASE : DP_SIDEBAND_MSG_DOWN_REQ_BASE;
2773         int tosend, total, offset;
2774         int retries = 0;
2775
2776 retry:
2777         total = len;
2778         offset = 0;
2779         do {
2780                 tosend = min3(mgr->max_dpcd_transaction_bytes, 16, total);
2781
2782                 ret = drm_dp_dpcd_write(mgr->aux, regbase + offset,
2783                                         &msg[offset],
2784                                         tosend);
2785                 if (ret != tosend) {
2786                         if (ret == -EIO && retries < 5) {
2787                                 retries++;
2788                                 goto retry;
2789                         }
2790                         drm_dbg_kms(mgr->dev, "failed to dpcd write %d %d\n", tosend, ret);
2791
2792                         return -EIO;
2793                 }
2794                 offset += tosend;
2795                 total -= tosend;
2796         } while (total > 0);
2797         return 0;
2798 }
2799
2800 static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr,
2801                                   struct drm_dp_sideband_msg_tx *txmsg)
2802 {
2803         struct drm_dp_mst_branch *mstb = txmsg->dst;
2804         u8 req_type;
2805
2806         req_type = txmsg->msg[0] & 0x7f;
2807         if (req_type == DP_CONNECTION_STATUS_NOTIFY ||
2808                 req_type == DP_RESOURCE_STATUS_NOTIFY ||
2809                 req_type == DP_CLEAR_PAYLOAD_ID_TABLE)
2810                 hdr->broadcast = 1;
2811         else
2812                 hdr->broadcast = 0;
2813         hdr->path_msg = txmsg->path_msg;
2814         if (hdr->broadcast) {
2815                 hdr->lct = 1;
2816                 hdr->lcr = 6;
2817         } else {
2818                 hdr->lct = mstb->lct;
2819                 hdr->lcr = mstb->lct - 1;
2820         }
2821
2822         memcpy(hdr->rad, mstb->rad, hdr->lct / 2);
2823
2824         return 0;
2825 }
2826 /*
2827  * process a single block of the next message in the sideband queue
2828  */
2829 static int process_single_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
2830                                    struct drm_dp_sideband_msg_tx *txmsg,
2831                                    bool up)
2832 {
2833         u8 chunk[48];
2834         struct drm_dp_sideband_msg_hdr hdr;
2835         int len, space, idx, tosend;
2836         int ret;
2837
2838         if (txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
2839                 return 0;
2840
2841         memset(&hdr, 0, sizeof(struct drm_dp_sideband_msg_hdr));
2842
2843         if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED)
2844                 txmsg->state = DRM_DP_SIDEBAND_TX_START_SEND;
2845
2846         /* make hdr from dst mst */
2847         ret = set_hdr_from_dst_qlock(&hdr, txmsg);
2848         if (ret < 0)
2849                 return ret;
2850
2851         /* amount left to send in this message */
2852         len = txmsg->cur_len - txmsg->cur_offset;
2853
2854         /* 48 - sideband msg size - 1 byte for data CRC, x header bytes */
2855         space = 48 - 1 - drm_dp_calc_sb_hdr_size(&hdr);
2856
2857         tosend = min(len, space);
2858         if (len == txmsg->cur_len)
2859                 hdr.somt = 1;
2860         if (space >= len)
2861                 hdr.eomt = 1;
2862
2863
2864         hdr.msg_len = tosend + 1;
2865         drm_dp_encode_sideband_msg_hdr(&hdr, chunk, &idx);
2866         memcpy(&chunk[idx], &txmsg->msg[txmsg->cur_offset], tosend);
2867         /* add crc at end */
2868         drm_dp_crc_sideband_chunk_req(&chunk[idx], tosend);
2869         idx += tosend + 1;
2870
2871         ret = drm_dp_send_sideband_msg(mgr, up, chunk, idx);
2872         if (ret) {
2873                 if (drm_debug_enabled(DRM_UT_DP)) {
2874                         struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2875
2876                         drm_printf(&p, "sideband msg failed to send\n");
2877                         drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2878                 }
2879                 return ret;
2880         }
2881
2882         txmsg->cur_offset += tosend;
2883         if (txmsg->cur_offset == txmsg->cur_len) {
2884                 txmsg->state = DRM_DP_SIDEBAND_TX_SENT;
2885                 return 1;
2886         }
2887         return 0;
2888 }
2889
2890 static void process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr *mgr)
2891 {
2892         struct drm_dp_sideband_msg_tx *txmsg;
2893         int ret;
2894
2895         WARN_ON(!mutex_is_locked(&mgr->qlock));
2896
2897         /* construct a chunk from the first msg in the tx_msg queue */
2898         if (list_empty(&mgr->tx_msg_downq))
2899                 return;
2900
2901         txmsg = list_first_entry(&mgr->tx_msg_downq,
2902                                  struct drm_dp_sideband_msg_tx, next);
2903         ret = process_single_tx_qlock(mgr, txmsg, false);
2904         if (ret < 0) {
2905                 drm_dbg_kms(mgr->dev, "failed to send msg in q %d\n", ret);
2906                 list_del(&txmsg->next);
2907                 txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
2908                 wake_up_all(&mgr->tx_waitq);
2909         }
2910 }
2911
2912 static void drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr *mgr,
2913                                  struct drm_dp_sideband_msg_tx *txmsg)
2914 {
2915         mutex_lock(&mgr->qlock);
2916         list_add_tail(&txmsg->next, &mgr->tx_msg_downq);
2917
2918         if (drm_debug_enabled(DRM_UT_DP)) {
2919                 struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2920
2921                 drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2922         }
2923
2924         if (list_is_singular(&mgr->tx_msg_downq))
2925                 process_single_down_tx_qlock(mgr);
2926         mutex_unlock(&mgr->qlock);
2927 }
2928
2929 static void
2930 drm_dp_dump_link_address(const struct drm_dp_mst_topology_mgr *mgr,
2931                          struct drm_dp_link_address_ack_reply *reply)
2932 {
2933         struct drm_dp_link_addr_reply_port *port_reply;
2934         int i;
2935
2936         for (i = 0; i < reply->nports; i++) {
2937                 port_reply = &reply->ports[i];
2938                 drm_dbg_kms(mgr->dev,
2939                             "port %d: input %d, pdt: %d, pn: %d, dpcd_rev: %02x, mcs: %d, ddps: %d, ldps %d, sdp %d/%d\n",
2940                             i,
2941                             port_reply->input_port,
2942                             port_reply->peer_device_type,
2943                             port_reply->port_number,
2944                             port_reply->dpcd_revision,
2945                             port_reply->mcs,
2946                             port_reply->ddps,
2947                             port_reply->legacy_device_plug_status,
2948                             port_reply->num_sdp_streams,
2949                             port_reply->num_sdp_stream_sinks);
2950         }
2951 }
2952
2953 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2954                                      struct drm_dp_mst_branch *mstb)
2955 {
2956         struct drm_dp_sideband_msg_tx *txmsg;
2957         struct drm_dp_link_address_ack_reply *reply;
2958         struct drm_dp_mst_port *port, *tmp;
2959         int i, ret, port_mask = 0;
2960         bool changed = false;
2961
2962         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2963         if (!txmsg)
2964                 return -ENOMEM;
2965
2966         txmsg->dst = mstb;
2967         build_link_address(txmsg);
2968
2969         mstb->link_address_sent = true;
2970         drm_dp_queue_down_tx(mgr, txmsg);
2971
2972         /* FIXME: Actually do some real error handling here */
2973         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
2974         if (ret <= 0) {
2975                 drm_err(mgr->dev, "Sending link address failed with %d\n", ret);
2976                 goto out;
2977         }
2978         if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
2979                 drm_err(mgr->dev, "link address NAK received\n");
2980                 ret = -EIO;
2981                 goto out;
2982         }
2983
2984         reply = &txmsg->reply.u.link_addr;
2985         drm_dbg_kms(mgr->dev, "link address reply: %d\n", reply->nports);
2986         drm_dp_dump_link_address(mgr, reply);
2987
2988         ret = drm_dp_check_mstb_guid(mstb, reply->guid);
2989         if (ret) {
2990                 char buf[64];
2991
2992                 drm_dp_mst_rad_to_str(mstb->rad, mstb->lct, buf, sizeof(buf));
2993                 drm_err(mgr->dev, "GUID check on %s failed: %d\n", buf, ret);
2994                 goto out;
2995         }
2996
2997         for (i = 0; i < reply->nports; i++) {
2998                 port_mask |= BIT(reply->ports[i].port_number);
2999                 ret = drm_dp_mst_handle_link_address_port(mstb, mgr->dev,
3000                                                           &reply->ports[i]);
3001                 if (ret == 1)
3002                         changed = true;
3003                 else if (ret < 0)
3004                         goto out;
3005         }
3006
3007         /* Prune any ports that are currently a part of mstb in our in-memory
3008          * topology, but were not seen in this link address. Usually this
3009          * means that they were removed while the topology was out of sync,
3010          * e.g. during suspend/resume
3011          */
3012         mutex_lock(&mgr->lock);
3013         list_for_each_entry_safe(port, tmp, &mstb->ports, next) {
3014                 if (port_mask & BIT(port->port_num))
3015                         continue;
3016
3017                 drm_dbg_kms(mgr->dev, "port %d was not in link address, removing\n",
3018                             port->port_num);
3019                 list_del(&port->next);
3020                 drm_dp_mst_topology_put_port(port);
3021                 changed = true;
3022         }
3023         mutex_unlock(&mgr->lock);
3024
3025 out:
3026         if (ret <= 0)
3027                 mstb->link_address_sent = false;
3028         kfree(txmsg);
3029         return ret < 0 ? ret : changed;
3030 }
3031
3032 static void
3033 drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
3034                                    struct drm_dp_mst_branch *mstb)
3035 {
3036         struct drm_dp_sideband_msg_tx *txmsg;
3037         int ret;
3038
3039         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3040         if (!txmsg)
3041                 return;
3042
3043         txmsg->dst = mstb;
3044         build_clear_payload_id_table(txmsg);
3045
3046         drm_dp_queue_down_tx(mgr, txmsg);
3047
3048         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3049         if (ret > 0 && txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3050                 drm_dbg_kms(mgr->dev, "clear payload table id nak received\n");
3051
3052         kfree(txmsg);
3053 }
3054
3055 static int
3056 drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
3057                                 struct drm_dp_mst_branch *mstb,
3058                                 struct drm_dp_mst_port *port)
3059 {
3060         struct drm_dp_enum_path_resources_ack_reply *path_res;
3061         struct drm_dp_sideband_msg_tx *txmsg;
3062         int ret;
3063
3064         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3065         if (!txmsg)
3066                 return -ENOMEM;
3067
3068         txmsg->dst = mstb;
3069         build_enum_path_resources(txmsg, port->port_num);
3070
3071         drm_dp_queue_down_tx(mgr, txmsg);
3072
3073         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3074         if (ret > 0) {
3075                 ret = 0;
3076                 path_res = &txmsg->reply.u.path_resources;
3077
3078                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3079                         drm_dbg_kms(mgr->dev, "enum path resources nak received\n");
3080                 } else {
3081                         if (port->port_num != path_res->port_number)
3082                                 DRM_ERROR("got incorrect port in response\n");
3083
3084                         drm_dbg_kms(mgr->dev, "enum path resources %d: %d %d\n",
3085                                     path_res->port_number,
3086                                     path_res->full_payload_bw_number,
3087                                     path_res->avail_payload_bw_number);
3088
3089                         /*
3090                          * If something changed, make sure we send a
3091                          * hotplug
3092                          */
3093                         if (port->full_pbn != path_res->full_payload_bw_number ||
3094                             port->fec_capable != path_res->fec_capable)
3095                                 ret = 1;
3096
3097                         port->full_pbn = path_res->full_payload_bw_number;
3098                         port->fec_capable = path_res->fec_capable;
3099                 }
3100         }
3101
3102         kfree(txmsg);
3103         return ret;
3104 }
3105
3106 static struct drm_dp_mst_port *drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch *mstb)
3107 {
3108         if (!mstb->port_parent)
3109                 return NULL;
3110
3111         if (mstb->port_parent->mstb != mstb)
3112                 return mstb->port_parent;
3113
3114         return drm_dp_get_last_connected_port_to_mstb(mstb->port_parent->parent);
3115 }
3116
3117 /*
3118  * Searches upwards in the topology starting from mstb to try to find the
3119  * closest available parent of mstb that's still connected to the rest of the
3120  * topology. This can be used in order to perform operations like releasing
3121  * payloads, where the branch device which owned the payload may no longer be
3122  * around and thus would require that the payload on the last living relative
3123  * be freed instead.
3124  */
3125 static struct drm_dp_mst_branch *
3126 drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr *mgr,
3127                                         struct drm_dp_mst_branch *mstb,
3128                                         int *port_num)
3129 {
3130         struct drm_dp_mst_branch *rmstb = NULL;
3131         struct drm_dp_mst_port *found_port;
3132
3133         mutex_lock(&mgr->lock);
3134         if (!mgr->mst_primary)
3135                 goto out;
3136
3137         do {
3138                 found_port = drm_dp_get_last_connected_port_to_mstb(mstb);
3139                 if (!found_port)
3140                         break;
3141
3142                 if (drm_dp_mst_topology_try_get_mstb(found_port->parent)) {
3143                         rmstb = found_port->parent;
3144                         *port_num = found_port->port_num;
3145                 } else {
3146                         /* Search again, starting from this parent */
3147                         mstb = found_port->parent;
3148                 }
3149         } while (!rmstb);
3150 out:
3151         mutex_unlock(&mgr->lock);
3152         return rmstb;
3153 }
3154
3155 static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
3156                                    struct drm_dp_mst_port *port,
3157                                    int id,
3158                                    int pbn)
3159 {
3160         struct drm_dp_sideband_msg_tx *txmsg;
3161         struct drm_dp_mst_branch *mstb;
3162         int ret, port_num;
3163         u8 sinks[DRM_DP_MAX_SDP_STREAMS];
3164         int i;
3165
3166         port_num = port->port_num;
3167         mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3168         if (!mstb) {
3169                 mstb = drm_dp_get_last_connected_port_and_mstb(mgr,
3170                                                                port->parent,
3171                                                                &port_num);
3172
3173                 if (!mstb)
3174                         return -EINVAL;
3175         }
3176
3177         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3178         if (!txmsg) {
3179                 ret = -ENOMEM;
3180                 goto fail_put;
3181         }
3182
3183         for (i = 0; i < port->num_sdp_streams; i++)
3184                 sinks[i] = i;
3185
3186         txmsg->dst = mstb;
3187         build_allocate_payload(txmsg, port_num,
3188                                id,
3189                                pbn, port->num_sdp_streams, sinks);
3190
3191         drm_dp_queue_down_tx(mgr, txmsg);
3192
3193         /*
3194          * FIXME: there is a small chance that between getting the last
3195          * connected mstb and sending the payload message, the last connected
3196          * mstb could also be removed from the topology. In the future, this
3197          * needs to be fixed by restarting the
3198          * drm_dp_get_last_connected_port_and_mstb() search in the event of a
3199          * timeout if the topology is still connected to the system.
3200          */
3201         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3202         if (ret > 0) {
3203                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3204                         ret = -EINVAL;
3205                 else
3206                         ret = 0;
3207         }
3208         kfree(txmsg);
3209 fail_put:
3210         drm_dp_mst_topology_put_mstb(mstb);
3211         return ret;
3212 }
3213
3214 int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
3215                                  struct drm_dp_mst_port *port, bool power_up)
3216 {
3217         struct drm_dp_sideband_msg_tx *txmsg;
3218         int ret;
3219
3220         port = drm_dp_mst_topology_get_port_validated(mgr, port);
3221         if (!port)
3222                 return -EINVAL;
3223
3224         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3225         if (!txmsg) {
3226                 drm_dp_mst_topology_put_port(port);
3227                 return -ENOMEM;
3228         }
3229
3230         txmsg->dst = port->parent;
3231         build_power_updown_phy(txmsg, port->port_num, power_up);
3232         drm_dp_queue_down_tx(mgr, txmsg);
3233
3234         ret = drm_dp_mst_wait_tx_reply(port->parent, txmsg);
3235         if (ret > 0) {
3236                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3237                         ret = -EINVAL;
3238                 else
3239                         ret = 0;
3240         }
3241         kfree(txmsg);
3242         drm_dp_mst_topology_put_port(port);
3243
3244         return ret;
3245 }
3246 EXPORT_SYMBOL(drm_dp_send_power_updown_phy);
3247
3248 int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
3249                 struct drm_dp_mst_port *port,
3250                 struct drm_dp_query_stream_enc_status_ack_reply *status)
3251 {
3252         struct drm_dp_sideband_msg_tx *txmsg;
3253         u8 nonce[7];
3254         int ret;
3255
3256         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3257         if (!txmsg)
3258                 return -ENOMEM;
3259
3260         port = drm_dp_mst_topology_get_port_validated(mgr, port);
3261         if (!port) {
3262                 ret = -EINVAL;
3263                 goto out_get_port;
3264         }
3265
3266         get_random_bytes(nonce, sizeof(nonce));
3267
3268         /*
3269          * "Source device targets the QUERY_STREAM_ENCRYPTION_STATUS message
3270          *  transaction at the MST Branch device directly connected to the
3271          *  Source"
3272          */
3273         txmsg->dst = mgr->mst_primary;
3274
3275         build_query_stream_enc_status(txmsg, port->vcpi.vcpi, nonce);
3276
3277         drm_dp_queue_down_tx(mgr, txmsg);
3278
3279         ret = drm_dp_mst_wait_tx_reply(mgr->mst_primary, txmsg);
3280         if (ret < 0) {
3281                 goto out;
3282         } else if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3283                 drm_dbg_kms(mgr->dev, "query encryption status nak received\n");
3284                 ret = -ENXIO;
3285                 goto out;
3286         }
3287
3288         ret = 0;
3289         memcpy(status, &txmsg->reply.u.enc_status, sizeof(*status));
3290
3291 out:
3292         drm_dp_mst_topology_put_port(port);
3293 out_get_port:
3294         kfree(txmsg);
3295         return ret;
3296 }
3297 EXPORT_SYMBOL(drm_dp_send_query_stream_enc_status);
3298
3299 static int drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
3300                                        int id,
3301                                        struct drm_dp_payload *payload)
3302 {
3303         int ret;
3304
3305         ret = drm_dp_dpcd_write_payload(mgr, id, payload);
3306         if (ret < 0) {
3307                 payload->payload_state = 0;
3308                 return ret;
3309         }
3310         payload->payload_state = DP_PAYLOAD_LOCAL;
3311         return 0;
3312 }
3313
3314 static int drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
3315                                        struct drm_dp_mst_port *port,
3316                                        int id,
3317                                        struct drm_dp_payload *payload)
3318 {
3319         int ret;
3320
3321         ret = drm_dp_payload_send_msg(mgr, port, id, port->vcpi.pbn);
3322         if (ret < 0)
3323                 return ret;
3324         payload->payload_state = DP_PAYLOAD_REMOTE;
3325         return ret;
3326 }
3327
3328 static int drm_dp_destroy_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
3329                                         struct drm_dp_mst_port *port,
3330                                         int id,
3331                                         struct drm_dp_payload *payload)
3332 {
3333         drm_dbg_kms(mgr->dev, "\n");
3334         /* it's okay for these to fail */
3335         if (port) {
3336                 drm_dp_payload_send_msg(mgr, port, id, 0);
3337         }
3338
3339         drm_dp_dpcd_write_payload(mgr, id, payload);
3340         payload->payload_state = DP_PAYLOAD_DELETE_LOCAL;
3341         return 0;
3342 }
3343
3344 static int drm_dp_destroy_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
3345                                         int id,
3346                                         struct drm_dp_payload *payload)
3347 {
3348         payload->payload_state = 0;
3349         return 0;
3350 }
3351
3352 /**
3353  * drm_dp_update_payload_part1() - Execute payload update part 1
3354  * @mgr: manager to use.
3355  * @start_slot: this is the cur slot
3356  *
3357  * NOTE: start_slot is a temporary workaround for non-atomic drivers,
3358  * this will be removed when non-atomic mst helpers are moved out of the helper
3359  *
3360  * This iterates over all proposed virtual channels, and tries to
3361  * allocate space in the link for them. For 0->slots transitions,
3362  * this step just writes the VCPI to the MST device. For slots->0
3363  * transitions, this writes the updated VCPIs and removes the
3364  * remote VC payloads.
3365  *
3366  * after calling this the driver should generate ACT and payload
3367  * packets.
3368  */
3369 int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr, int start_slot)
3370 {
3371         struct drm_dp_payload req_payload;
3372         struct drm_dp_mst_port *port;
3373         int i, j;
3374         int cur_slots = start_slot;
3375         bool skip;
3376
3377         mutex_lock(&mgr->payload_lock);
3378         for (i = 0; i < mgr->max_payloads; i++) {
3379                 struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
3380                 struct drm_dp_payload *payload = &mgr->payloads[i];
3381                 bool put_port = false;
3382
3383                 /* solve the current payloads - compare to the hw ones
3384                    - update the hw view */
3385                 req_payload.start_slot = cur_slots;
3386                 if (vcpi) {
3387                         port = container_of(vcpi, struct drm_dp_mst_port,
3388                                             vcpi);
3389
3390                         mutex_lock(&mgr->lock);
3391                         skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
3392                         mutex_unlock(&mgr->lock);
3393
3394                         if (skip) {
3395                                 drm_dbg_kms(mgr->dev,
3396                                             "Virtual channel %d is not in current topology\n",
3397                                             i);
3398                                 continue;
3399                         }
3400                         /* Validated ports don't matter if we're releasing
3401                          * VCPI
3402                          */
3403                         if (vcpi->num_slots) {
3404                                 port = drm_dp_mst_topology_get_port_validated(
3405                                     mgr, port);
3406                                 if (!port) {
3407                                         if (vcpi->num_slots == payload->num_slots) {
3408                                                 cur_slots += vcpi->num_slots;
3409                                                 payload->start_slot = req_payload.start_slot;
3410                                                 continue;
3411                                         } else {
3412                                                 drm_dbg_kms(mgr->dev,
3413                                                             "Fail:set payload to invalid sink");
3414                                                 mutex_unlock(&mgr->payload_lock);
3415                                                 return -EINVAL;
3416                                         }
3417                                 }
3418                                 put_port = true;
3419                         }
3420
3421                         req_payload.num_slots = vcpi->num_slots;
3422                         req_payload.vcpi = vcpi->vcpi;
3423                 } else {
3424                         port = NULL;
3425                         req_payload.num_slots = 0;
3426                 }
3427
3428                 payload->start_slot = req_payload.start_slot;
3429                 /* work out what is required to happen with this payload */
3430                 if (payload->num_slots != req_payload.num_slots) {
3431
3432                         /* need to push an update for this payload */
3433                         if (req_payload.num_slots) {
3434                                 drm_dp_create_payload_step1(mgr, vcpi->vcpi,
3435                                                             &req_payload);
3436                                 payload->num_slots = req_payload.num_slots;
3437                                 payload->vcpi = req_payload.vcpi;
3438
3439                         } else if (payload->num_slots) {
3440                                 payload->num_slots = 0;
3441                                 drm_dp_destroy_payload_step1(mgr, port,
3442                                                              payload->vcpi,
3443                                                              payload);
3444                                 req_payload.payload_state =
3445                                         payload->payload_state;
3446                                 payload->start_slot = 0;
3447                         }
3448                         payload->payload_state = req_payload.payload_state;
3449                 }
3450                 cur_slots += req_payload.num_slots;
3451
3452                 if (put_port)
3453                         drm_dp_mst_topology_put_port(port);
3454         }
3455
3456         for (i = 0; i < mgr->max_payloads; /* do nothing */) {
3457                 if (mgr->payloads[i].payload_state != DP_PAYLOAD_DELETE_LOCAL) {
3458                         i++;
3459                         continue;
3460                 }
3461
3462                 drm_dbg_kms(mgr->dev, "removing payload %d\n", i);
3463                 for (j = i; j < mgr->max_payloads - 1; j++) {
3464                         mgr->payloads[j] = mgr->payloads[j + 1];
3465                         mgr->proposed_vcpis[j] = mgr->proposed_vcpis[j + 1];
3466
3467                         if (mgr->proposed_vcpis[j] &&
3468                             mgr->proposed_vcpis[j]->num_slots) {
3469                                 set_bit(j + 1, &mgr->payload_mask);
3470                         } else {
3471                                 clear_bit(j + 1, &mgr->payload_mask);
3472                         }
3473                 }
3474
3475                 memset(&mgr->payloads[mgr->max_payloads - 1], 0,
3476                        sizeof(struct drm_dp_payload));
3477                 mgr->proposed_vcpis[mgr->max_payloads - 1] = NULL;
3478                 clear_bit(mgr->max_payloads, &mgr->payload_mask);
3479         }
3480         mutex_unlock(&mgr->payload_lock);
3481
3482         return 0;
3483 }
3484 EXPORT_SYMBOL(drm_dp_update_payload_part1);
3485
3486 /**
3487  * drm_dp_update_payload_part2() - Execute payload update part 2
3488  * @mgr: manager to use.
3489  *
3490  * This iterates over all proposed virtual channels, and tries to
3491  * allocate space in the link for them. For 0->slots transitions,
3492  * this step writes the remote VC payload commands. For slots->0
3493  * this just resets some internal state.
3494  */
3495 int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
3496 {
3497         struct drm_dp_mst_port *port;
3498         int i;
3499         int ret = 0;
3500         bool skip;
3501
3502         mutex_lock(&mgr->payload_lock);
3503         for (i = 0; i < mgr->max_payloads; i++) {
3504
3505                 if (!mgr->proposed_vcpis[i])
3506                         continue;
3507
3508                 port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
3509
3510                 mutex_lock(&mgr->lock);
3511                 skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
3512                 mutex_unlock(&mgr->lock);
3513
3514                 if (skip)
3515                         continue;
3516
3517                 drm_dbg_kms(mgr->dev, "payload %d %d\n", i, mgr->payloads[i].payload_state);
3518                 if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL) {
3519                         ret = drm_dp_create_payload_step2(mgr, port, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
3520                 } else if (mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) {
3521                         ret = drm_dp_destroy_payload_step2(mgr, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
3522                 }
3523                 if (ret) {
3524                         mutex_unlock(&mgr->payload_lock);
3525                         return ret;
3526                 }
3527         }
3528         mutex_unlock(&mgr->payload_lock);
3529         return 0;
3530 }
3531 EXPORT_SYMBOL(drm_dp_update_payload_part2);
3532
3533 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
3534                                  struct drm_dp_mst_port *port,
3535                                  int offset, int size, u8 *bytes)
3536 {
3537         int ret = 0;
3538         struct drm_dp_sideband_msg_tx *txmsg;
3539         struct drm_dp_mst_branch *mstb;
3540
3541         mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3542         if (!mstb)
3543                 return -EINVAL;
3544
3545         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3546         if (!txmsg) {
3547                 ret = -ENOMEM;
3548                 goto fail_put;
3549         }
3550
3551         build_dpcd_read(txmsg, port->port_num, offset, size);
3552         txmsg->dst = port->parent;
3553
3554         drm_dp_queue_down_tx(mgr, txmsg);
3555
3556         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3557         if (ret < 0)
3558                 goto fail_free;
3559
3560         if (txmsg->reply.reply_type == 1) {
3561                 drm_dbg_kms(mgr->dev, "mstb %p port %d: DPCD read on addr 0x%x for %d bytes NAKed\n",
3562                             mstb, port->port_num, offset, size);
3563                 ret = -EIO;
3564                 goto fail_free;
3565         }
3566
3567         if (txmsg->reply.u.remote_dpcd_read_ack.num_bytes != size) {
3568                 ret = -EPROTO;
3569                 goto fail_free;
3570         }
3571
3572         ret = min_t(size_t, txmsg->reply.u.remote_dpcd_read_ack.num_bytes,
3573                     size);
3574         memcpy(bytes, txmsg->reply.u.remote_dpcd_read_ack.bytes, ret);
3575
3576 fail_free:
3577         kfree(txmsg);
3578 fail_put:
3579         drm_dp_mst_topology_put_mstb(mstb);
3580
3581         return ret;
3582 }
3583
3584 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
3585                                   struct drm_dp_mst_port *port,
3586                                   int offset, int size, u8 *bytes)
3587 {
3588         int ret;
3589         struct drm_dp_sideband_msg_tx *txmsg;
3590         struct drm_dp_mst_branch *mstb;
3591
3592         mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3593         if (!mstb)
3594                 return -EINVAL;
3595
3596         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3597         if (!txmsg) {
3598                 ret = -ENOMEM;
3599                 goto fail_put;
3600         }
3601
3602         build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
3603         txmsg->dst = mstb;
3604
3605         drm_dp_queue_down_tx(mgr, txmsg);
3606
3607         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3608         if (ret > 0) {
3609                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3610                         ret = -EIO;
3611                 else
3612                         ret = size;
3613         }
3614
3615         kfree(txmsg);
3616 fail_put:
3617         drm_dp_mst_topology_put_mstb(mstb);
3618         return ret;
3619 }
3620
3621 static int drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx *msg, u8 req_type)
3622 {
3623         struct drm_dp_sideband_msg_reply_body reply;
3624
3625         reply.reply_type = DP_SIDEBAND_REPLY_ACK;
3626         reply.req_type = req_type;
3627         drm_dp_encode_sideband_reply(&reply, msg);
3628         return 0;
3629 }
3630
3631 static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
3632                                     struct drm_dp_mst_branch *mstb,
3633                                     int req_type, bool broadcast)
3634 {
3635         struct drm_dp_sideband_msg_tx *txmsg;
3636
3637         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3638         if (!txmsg)
3639                 return -ENOMEM;
3640
3641         txmsg->dst = mstb;
3642         drm_dp_encode_up_ack_reply(txmsg, req_type);
3643
3644         mutex_lock(&mgr->qlock);
3645         /* construct a chunk from the first msg in the tx_msg queue */
3646         process_single_tx_qlock(mgr, txmsg, true);
3647         mutex_unlock(&mgr->qlock);
3648
3649         kfree(txmsg);
3650         return 0;
3651 }
3652
3653 /**
3654  * drm_dp_get_vc_payload_bw - get the VC payload BW for an MST link
3655  * @mgr: The &drm_dp_mst_topology_mgr to use
3656  * @link_rate: link rate in 10kbits/s units
3657  * @link_lane_count: lane count
3658  *
3659  * Calculate the total bandwidth of a MultiStream Transport link. The returned
3660  * value is in units of PBNs/(timeslots/1 MTP). This value can be used to
3661  * convert the number of PBNs required for a given stream to the number of
3662  * timeslots this stream requires in each MTP.
3663  */
3664 int drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr *mgr,
3665                              int link_rate, int link_lane_count)
3666 {
3667         if (link_rate == 0 || link_lane_count == 0)
3668                 drm_dbg_kms(mgr->dev, "invalid link rate/lane count: (%d / %d)\n",
3669                             link_rate, link_lane_count);
3670
3671         /* See DP v2.0 2.6.4.2, VCPayload_Bandwidth_for_OneTimeSlotPer_MTP_Allocation */
3672         return link_rate * link_lane_count / 54000;
3673 }
3674 EXPORT_SYMBOL(drm_dp_get_vc_payload_bw);
3675
3676 /**
3677  * drm_dp_read_mst_cap() - check whether or not a sink supports MST
3678  * @aux: The DP AUX channel to use
3679  * @dpcd: A cached copy of the DPCD capabilities for this sink
3680  *
3681  * Returns: %True if the sink supports MST, %false otherwise
3682  */
3683 bool drm_dp_read_mst_cap(struct drm_dp_aux *aux,
3684                          const u8 dpcd[DP_RECEIVER_CAP_SIZE])
3685 {
3686         u8 mstm_cap;
3687
3688         if (dpcd[DP_DPCD_REV] < DP_DPCD_REV_12)
3689                 return false;
3690
3691         if (drm_dp_dpcd_readb(aux, DP_MSTM_CAP, &mstm_cap) != 1)
3692                 return false;
3693
3694         return mstm_cap & DP_MST_CAP;
3695 }
3696 EXPORT_SYMBOL(drm_dp_read_mst_cap);
3697
3698 /**
3699  * drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a topology manager
3700  * @mgr: manager to set state for
3701  * @mst_state: true to enable MST on this connector - false to disable.
3702  *
3703  * This is called by the driver when it detects an MST capable device plugged
3704  * into a DP MST capable port, or when a DP MST capable device is unplugged.
3705  */
3706 int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state)
3707 {
3708         int ret = 0;
3709         struct drm_dp_mst_branch *mstb = NULL;
3710
3711         mutex_lock(&mgr->payload_lock);
3712         mutex_lock(&mgr->lock);
3713         if (mst_state == mgr->mst_state)
3714                 goto out_unlock;
3715
3716         mgr->mst_state = mst_state;
3717         /* set the device into MST mode */
3718         if (mst_state) {
3719                 struct drm_dp_payload reset_pay;
3720                 int lane_count;
3721                 int link_rate;
3722
3723                 WARN_ON(mgr->mst_primary);
3724
3725                 /* get dpcd info */
3726                 ret = drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd);
3727                 if (ret < 0) {
3728                         drm_dbg_kms(mgr->dev, "%s: failed to read DPCD, ret %d\n",
3729                                     mgr->aux->name, ret);
3730                         goto out_unlock;
3731                 }
3732
3733                 lane_count = min_t(int, mgr->dpcd[2] & DP_MAX_LANE_COUNT_MASK, mgr->max_lane_count);
3734                 link_rate = min_t(int, drm_dp_bw_code_to_link_rate(mgr->dpcd[1]), mgr->max_link_rate);
3735                 mgr->pbn_div = drm_dp_get_vc_payload_bw(mgr,
3736                                                         link_rate,
3737                                                         lane_count);
3738                 if (mgr->pbn_div == 0) {
3739                         ret = -EINVAL;
3740                         goto out_unlock;
3741                 }
3742
3743                 /* add initial branch device at LCT 1 */
3744                 mstb = drm_dp_add_mst_branch_device(1, NULL);
3745                 if (mstb == NULL) {
3746                         ret = -ENOMEM;
3747                         goto out_unlock;
3748                 }
3749                 mstb->mgr = mgr;
3750
3751                 /* give this the main reference */
3752                 mgr->mst_primary = mstb;
3753                 drm_dp_mst_topology_get_mstb(mgr->mst_primary);
3754
3755                 ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3756                                          DP_MST_EN |
3757                                          DP_UP_REQ_EN |
3758                                          DP_UPSTREAM_IS_SRC);
3759                 if (ret < 0)
3760                         goto out_unlock;
3761
3762                 reset_pay.start_slot = 0;
3763                 reset_pay.num_slots = 0x3f;
3764                 drm_dp_dpcd_write_payload(mgr, 0, &reset_pay);
3765
3766                 queue_work(system_long_wq, &mgr->work);
3767
3768                 ret = 0;
3769         } else {
3770                 /* disable MST on the device */
3771                 mstb = mgr->mst_primary;
3772                 mgr->mst_primary = NULL;
3773                 /* this can fail if the device is gone */
3774                 drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
3775                 ret = 0;
3776                 memset(mgr->payloads, 0,
3777                        mgr->max_payloads * sizeof(mgr->payloads[0]));
3778                 memset(mgr->proposed_vcpis, 0,
3779                        mgr->max_payloads * sizeof(mgr->proposed_vcpis[0]));
3780                 mgr->payload_mask = 0;
3781                 set_bit(0, &mgr->payload_mask);
3782                 mgr->vcpi_mask = 0;
3783                 mgr->payload_id_table_cleared = false;
3784         }
3785
3786 out_unlock:
3787         mutex_unlock(&mgr->lock);
3788         mutex_unlock(&mgr->payload_lock);
3789         if (mstb)
3790                 drm_dp_mst_topology_put_mstb(mstb);
3791         return ret;
3792
3793 }
3794 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_set_mst);
3795
3796 static void
3797 drm_dp_mst_topology_mgr_invalidate_mstb(struct drm_dp_mst_branch *mstb)
3798 {
3799         struct drm_dp_mst_port *port;
3800
3801         /* The link address will need to be re-sent on resume */
3802         mstb->link_address_sent = false;
3803
3804         list_for_each_entry(port, &mstb->ports, next)
3805                 if (port->mstb)
3806                         drm_dp_mst_topology_mgr_invalidate_mstb(port->mstb);
3807 }
3808
3809 /**
3810  * drm_dp_mst_topology_mgr_suspend() - suspend the MST manager
3811  * @mgr: manager to suspend
3812  *
3813  * This function tells the MST device that we can't handle UP messages
3814  * anymore. This should stop it from sending any since we are suspended.
3815  */
3816 void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr)
3817 {
3818         mutex_lock(&mgr->lock);
3819         drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3820                            DP_MST_EN | DP_UPSTREAM_IS_SRC);
3821         mutex_unlock(&mgr->lock);
3822         flush_work(&mgr->up_req_work);
3823         flush_work(&mgr->work);
3824         flush_work(&mgr->delayed_destroy_work);
3825
3826         mutex_lock(&mgr->lock);
3827         if (mgr->mst_state && mgr->mst_primary)
3828                 drm_dp_mst_topology_mgr_invalidate_mstb(mgr->mst_primary);
3829         mutex_unlock(&mgr->lock);
3830 }
3831 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_suspend);
3832
3833 /**
3834  * drm_dp_mst_topology_mgr_resume() - resume the MST manager
3835  * @mgr: manager to resume
3836  * @sync: whether or not to perform topology reprobing synchronously
3837  *
3838  * This will fetch DPCD and see if the device is still there,
3839  * if it is, it will rewrite the MSTM control bits, and return.
3840  *
3841  * If the device fails this returns -1, and the driver should do
3842  * a full MST reprobe, in case we were undocked.
3843  *
3844  * During system resume (where it is assumed that the driver will be calling
3845  * drm_atomic_helper_resume()) this function should be called beforehand with
3846  * @sync set to true. In contexts like runtime resume where the driver is not
3847  * expected to be calling drm_atomic_helper_resume(), this function should be
3848  * called with @sync set to false in order to avoid deadlocking.
3849  *
3850  * Returns: -1 if the MST topology was removed while we were suspended, 0
3851  * otherwise.
3852  */
3853 int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr,
3854                                    bool sync)
3855 {
3856         int ret;
3857         u8 guid[16];
3858
3859         mutex_lock(&mgr->lock);
3860         if (!mgr->mst_primary)
3861                 goto out_fail;
3862
3863         if (drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd) < 0) {
3864                 drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n");
3865                 goto out_fail;
3866         }
3867
3868         ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3869                                  DP_MST_EN |
3870                                  DP_UP_REQ_EN |
3871                                  DP_UPSTREAM_IS_SRC);
3872         if (ret < 0) {
3873                 drm_dbg_kms(mgr->dev, "mst write failed - undocked during suspend?\n");
3874                 goto out_fail;
3875         }
3876
3877         /* Some hubs forget their guids after they resume */
3878         ret = drm_dp_dpcd_read(mgr->aux, DP_GUID, guid, 16);
3879         if (ret != 16) {
3880                 drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n");
3881                 goto out_fail;
3882         }
3883
3884         ret = drm_dp_check_mstb_guid(mgr->mst_primary, guid);
3885         if (ret) {
3886                 drm_dbg_kms(mgr->dev, "check mstb failed - undocked during suspend?\n");
3887                 goto out_fail;
3888         }
3889
3890         /*
3891          * For the final step of resuming the topology, we need to bring the
3892          * state of our in-memory topology back into sync with reality. So,
3893          * restart the probing process as if we're probing a new hub
3894          */
3895         queue_work(system_long_wq, &mgr->work);
3896         mutex_unlock(&mgr->lock);
3897
3898         if (sync) {
3899                 drm_dbg_kms(mgr->dev,
3900                             "Waiting for link probe work to finish re-syncing topology...\n");
3901                 flush_work(&mgr->work);
3902         }
3903
3904         return 0;
3905
3906 out_fail:
3907         mutex_unlock(&mgr->lock);
3908         return -1;
3909 }
3910 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume);
3911
3912 static bool
3913 drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up,
3914                       struct drm_dp_mst_branch **mstb)
3915 {
3916         int len;
3917         u8 replyblock[32];
3918         int replylen, curreply;
3919         int ret;
3920         u8 hdrlen;
3921         struct drm_dp_sideband_msg_hdr hdr;
3922         struct drm_dp_sideband_msg_rx *msg =
3923                 up ? &mgr->up_req_recv : &mgr->down_rep_recv;
3924         int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE :
3925                            DP_SIDEBAND_MSG_DOWN_REP_BASE;
3926
3927         if (!up)
3928                 *mstb = NULL;
3929
3930         len = min(mgr->max_dpcd_transaction_bytes, 16);
3931         ret = drm_dp_dpcd_read(mgr->aux, basereg, replyblock, len);
3932         if (ret != len) {
3933                 drm_dbg_kms(mgr->dev, "failed to read DPCD down rep %d %d\n", len, ret);
3934                 return false;
3935         }
3936
3937         ret = drm_dp_decode_sideband_msg_hdr(mgr, &hdr, replyblock, len, &hdrlen);
3938         if (ret == false) {
3939                 print_hex_dump(KERN_DEBUG, "failed hdr", DUMP_PREFIX_NONE, 16,
3940                                1, replyblock, len, false);
3941                 drm_dbg_kms(mgr->dev, "ERROR: failed header\n");
3942                 return false;
3943         }
3944
3945         if (!up) {
3946                 /* Caller is responsible for giving back this reference */
3947                 *mstb = drm_dp_get_mst_branch_device(mgr, hdr.lct, hdr.rad);
3948                 if (!*mstb) {
3949                         drm_dbg_kms(mgr->dev, "Got MST reply from unknown device %d\n", hdr.lct);
3950                         return false;
3951                 }
3952         }
3953
3954         if (!drm_dp_sideband_msg_set_header(msg, &hdr, hdrlen)) {
3955                 drm_dbg_kms(mgr->dev, "sideband msg set header failed %d\n", replyblock[0]);
3956                 return false;
3957         }
3958
3959         replylen = min(msg->curchunk_len, (u8)(len - hdrlen));
3960         ret = drm_dp_sideband_append_payload(msg, replyblock + hdrlen, replylen);
3961         if (!ret) {
3962                 drm_dbg_kms(mgr->dev, "sideband msg build failed %d\n", replyblock[0]);
3963                 return false;
3964         }
3965
3966         replylen = msg->curchunk_len + msg->curchunk_hdrlen - len;
3967         curreply = len;
3968         while (replylen > 0) {
3969                 len = min3(replylen, mgr->max_dpcd_transaction_bytes, 16);
3970                 ret = drm_dp_dpcd_read(mgr->aux, basereg + curreply,
3971                                     replyblock, len);
3972                 if (ret != len) {
3973                         drm_dbg_kms(mgr->dev, "failed to read a chunk (len %d, ret %d)\n",
3974                                     len, ret);
3975                         return false;
3976                 }
3977
3978                 ret = drm_dp_sideband_append_payload(msg, replyblock, len);
3979                 if (!ret) {
3980                         drm_dbg_kms(mgr->dev, "failed to build sideband msg\n");
3981                         return false;
3982                 }
3983
3984                 curreply += len;
3985                 replylen -= len;
3986         }
3987         return true;
3988 }
3989
3990 static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
3991 {
3992         struct drm_dp_sideband_msg_tx *txmsg;
3993         struct drm_dp_mst_branch *mstb = NULL;
3994         struct drm_dp_sideband_msg_rx *msg = &mgr->down_rep_recv;
3995
3996         if (!drm_dp_get_one_sb_msg(mgr, false, &mstb))
3997                 goto out;
3998
3999         /* Multi-packet message transmission, don't clear the reply */
4000         if (!msg->have_eomt)
4001                 goto out;
4002
4003         /* find the message */
4004         mutex_lock(&mgr->qlock);
4005         txmsg = list_first_entry_or_null(&mgr->tx_msg_downq,
4006                                          struct drm_dp_sideband_msg_tx, next);
4007         mutex_unlock(&mgr->qlock);
4008
4009         /* Were we actually expecting a response, and from this mstb? */
4010         if (!txmsg || txmsg->dst != mstb) {
4011                 struct drm_dp_sideband_msg_hdr *hdr;
4012
4013                 hdr = &msg->initial_hdr;
4014                 drm_dbg_kms(mgr->dev, "Got MST reply with no msg %p %d %d %02x %02x\n",
4015                             mstb, hdr->seqno, hdr->lct, hdr->rad[0], msg->msg[0]);
4016                 goto out_clear_reply;
4017         }
4018
4019         drm_dp_sideband_parse_reply(mgr, msg, &txmsg->reply);
4020
4021         if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
4022                 drm_dbg_kms(mgr->dev,
4023                             "Got NAK reply: req 0x%02x (%s), reason 0x%02x (%s), nak data 0x%02x\n",
4024                             txmsg->reply.req_type,
4025                             drm_dp_mst_req_type_str(txmsg->reply.req_type),
4026                             txmsg->reply.u.nak.reason,
4027                             drm_dp_mst_nak_reason_str(txmsg->reply.u.nak.reason),
4028                             txmsg->reply.u.nak.nak_data);
4029         }
4030
4031         memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
4032         drm_dp_mst_topology_put_mstb(mstb);
4033
4034         mutex_lock(&mgr->qlock);
4035         txmsg->state = DRM_DP_SIDEBAND_TX_RX;
4036         list_del(&txmsg->next);
4037         mutex_unlock(&mgr->qlock);
4038
4039         wake_up_all(&mgr->tx_waitq);
4040
4041         return 0;
4042
4043 out_clear_reply:
4044         memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
4045 out:
4046         if (mstb)
4047                 drm_dp_mst_topology_put_mstb(mstb);
4048
4049         return 0;
4050 }
4051
4052 static inline bool
4053 drm_dp_mst_process_up_req(struct drm_dp_mst_topology_mgr *mgr,
4054                           struct drm_dp_pending_up_req *up_req)
4055 {
4056         struct drm_dp_mst_branch *mstb = NULL;
4057         struct drm_dp_sideband_msg_req_body *msg = &up_req->msg;
4058         struct drm_dp_sideband_msg_hdr *hdr = &up_req->hdr;
4059         bool hotplug = false;
4060
4061         if (hdr->broadcast) {
4062                 const u8 *guid = NULL;
4063
4064                 if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY)
4065                         guid = msg->u.conn_stat.guid;
4066                 else if (msg->req_type == DP_RESOURCE_STATUS_NOTIFY)
4067                         guid = msg->u.resource_stat.guid;
4068
4069                 if (guid)
4070                         mstb = drm_dp_get_mst_branch_device_by_guid(mgr, guid);
4071         } else {
4072                 mstb = drm_dp_get_mst_branch_device(mgr, hdr->lct, hdr->rad);
4073         }
4074
4075         if (!mstb) {
4076                 drm_dbg_kms(mgr->dev, "Got MST reply from unknown device %d\n", hdr->lct);
4077                 return false;
4078         }
4079
4080         /* TODO: Add missing handler for DP_RESOURCE_STATUS_NOTIFY events */
4081         if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY) {
4082                 drm_dp_mst_handle_conn_stat(mstb, &msg->u.conn_stat);
4083                 hotplug = true;
4084         }
4085
4086         drm_dp_mst_topology_put_mstb(mstb);
4087         return hotplug;
4088 }
4089
4090 static void drm_dp_mst_up_req_work(struct work_struct *work)
4091 {
4092         struct drm_dp_mst_topology_mgr *mgr =
4093                 container_of(work, struct drm_dp_mst_topology_mgr,
4094                              up_req_work);
4095         struct drm_dp_pending_up_req *up_req;
4096         bool send_hotplug = false;
4097
4098         mutex_lock(&mgr->probe_lock);
4099         while (true) {
4100                 mutex_lock(&mgr->up_req_lock);
4101                 up_req = list_first_entry_or_null(&mgr->up_req_list,
4102                                                   struct drm_dp_pending_up_req,
4103                                                   next);
4104                 if (up_req)
4105                         list_del(&up_req->next);
4106                 mutex_unlock(&mgr->up_req_lock);
4107
4108                 if (!up_req)
4109                         break;
4110
4111                 send_hotplug |= drm_dp_mst_process_up_req(mgr, up_req);
4112                 kfree(up_req);
4113         }
4114         mutex_unlock(&mgr->probe_lock);
4115
4116         if (send_hotplug)
4117                 drm_kms_helper_hotplug_event(mgr->dev);
4118 }
4119
4120 static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
4121 {
4122         struct drm_dp_pending_up_req *up_req;
4123
4124         if (!drm_dp_get_one_sb_msg(mgr, true, NULL))
4125                 goto out;
4126
4127         if (!mgr->up_req_recv.have_eomt)
4128                 return 0;
4129
4130         up_req = kzalloc(sizeof(*up_req), GFP_KERNEL);
4131         if (!up_req)
4132                 return -ENOMEM;
4133
4134         INIT_LIST_HEAD(&up_req->next);
4135
4136         drm_dp_sideband_parse_req(mgr, &mgr->up_req_recv, &up_req->msg);
4137
4138         if (up_req->msg.req_type != DP_CONNECTION_STATUS_NOTIFY &&
4139             up_req->msg.req_type != DP_RESOURCE_STATUS_NOTIFY) {
4140                 drm_dbg_kms(mgr->dev, "Received unknown up req type, ignoring: %x\n",
4141                             up_req->msg.req_type);
4142                 kfree(up_req);
4143                 goto out;
4144         }
4145
4146         drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, up_req->msg.req_type,
4147                                  false);
4148
4149         if (up_req->msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
4150                 const struct drm_dp_connection_status_notify *conn_stat =
4151                         &up_req->msg.u.conn_stat;
4152
4153                 drm_dbg_kms(mgr->dev, "Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n",
4154                             conn_stat->port_number,
4155                             conn_stat->legacy_device_plug_status,
4156                             conn_stat->displayport_device_plug_status,
4157                             conn_stat->message_capability_status,
4158                             conn_stat->input_port,
4159                             conn_stat->peer_device_type);
4160         } else if (up_req->msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
4161                 const struct drm_dp_resource_status_notify *res_stat =
4162                         &up_req->msg.u.resource_stat;
4163
4164                 drm_dbg_kms(mgr->dev, "Got RSN: pn: %d avail_pbn %d\n",
4165                             res_stat->port_number,
4166                             res_stat->available_pbn);
4167         }
4168
4169         up_req->hdr = mgr->up_req_recv.initial_hdr;
4170         mutex_lock(&mgr->up_req_lock);
4171         list_add_tail(&up_req->next, &mgr->up_req_list);
4172         mutex_unlock(&mgr->up_req_lock);
4173         queue_work(system_long_wq, &mgr->up_req_work);
4174
4175 out:
4176         memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
4177         return 0;
4178 }
4179
4180 /**
4181  * drm_dp_mst_hpd_irq() - MST hotplug IRQ notify
4182  * @mgr: manager to notify irq for.
4183  * @esi: 4 bytes from SINK_COUNT_ESI
4184  * @handled: whether the hpd interrupt was consumed or not
4185  *
4186  * This should be called from the driver when it detects a short IRQ,
4187  * along with the value of the DEVICE_SERVICE_IRQ_VECTOR_ESI0. The
4188  * topology manager will process the sideband messages received as a result
4189  * of this.
4190  */
4191 int drm_dp_mst_hpd_irq(struct drm_dp_mst_topology_mgr *mgr, u8 *esi, bool *handled)
4192 {
4193         int ret = 0;
4194         int sc;
4195         *handled = false;
4196         sc = DP_GET_SINK_COUNT(esi[0]);
4197
4198         if (sc != mgr->sink_count) {
4199                 mgr->sink_count = sc;
4200                 *handled = true;
4201         }
4202
4203         if (esi[1] & DP_DOWN_REP_MSG_RDY) {
4204                 ret = drm_dp_mst_handle_down_rep(mgr);
4205                 *handled = true;
4206         }
4207
4208         if (esi[1] & DP_UP_REQ_MSG_RDY) {
4209                 ret |= drm_dp_mst_handle_up_req(mgr);
4210                 *handled = true;
4211         }
4212
4213         drm_dp_mst_kick_tx(mgr);
4214         return ret;
4215 }
4216 EXPORT_SYMBOL(drm_dp_mst_hpd_irq);
4217
4218 /**
4219  * drm_dp_mst_detect_port() - get connection status for an MST port
4220  * @connector: DRM connector for this port
4221  * @ctx: The acquisition context to use for grabbing locks
4222  * @mgr: manager for this port
4223  * @port: pointer to a port
4224  *
4225  * This returns the current connection state for a port.
4226  */
4227 int
4228 drm_dp_mst_detect_port(struct drm_connector *connector,
4229                        struct drm_modeset_acquire_ctx *ctx,
4230                        struct drm_dp_mst_topology_mgr *mgr,
4231                        struct drm_dp_mst_port *port)
4232 {
4233         int ret;
4234
4235         /* we need to search for the port in the mgr in case it's gone */
4236         port = drm_dp_mst_topology_get_port_validated(mgr, port);
4237         if (!port)
4238                 return connector_status_disconnected;
4239
4240         ret = drm_modeset_lock(&mgr->base.lock, ctx);
4241         if (ret)
4242                 goto out;
4243
4244         ret = connector_status_disconnected;
4245
4246         if (!port->ddps)
4247                 goto out;
4248
4249         switch (port->pdt) {
4250         case DP_PEER_DEVICE_NONE:
4251                 break;
4252         case DP_PEER_DEVICE_MST_BRANCHING:
4253                 if (!port->mcs)
4254                         ret = connector_status_connected;
4255                 break;
4256
4257         case DP_PEER_DEVICE_SST_SINK:
4258                 ret = connector_status_connected;
4259                 /* for logical ports - cache the EDID */
4260                 if (port->port_num >= DP_MST_LOGICAL_PORT_0 && !port->cached_edid)
4261                         port->cached_edid = drm_get_edid(connector, &port->aux.ddc);
4262                 break;
4263         case DP_PEER_DEVICE_DP_LEGACY_CONV:
4264                 if (port->ldps)
4265                         ret = connector_status_connected;
4266                 break;
4267         }
4268 out:
4269         drm_dp_mst_topology_put_port(port);
4270         return ret;
4271 }
4272 EXPORT_SYMBOL(drm_dp_mst_detect_port);
4273
4274 /**
4275  * drm_dp_mst_get_edid() - get EDID for an MST port
4276  * @connector: toplevel connector to get EDID for
4277  * @mgr: manager for this port
4278  * @port: unverified pointer to a port.
4279  *
4280  * This returns an EDID for the port connected to a connector,
4281  * It validates the pointer still exists so the caller doesn't require a
4282  * reference.
4283  */
4284 struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4285 {
4286         struct edid *edid = NULL;
4287
4288         /* we need to search for the port in the mgr in case it's gone */
4289         port = drm_dp_mst_topology_get_port_validated(mgr, port);
4290         if (!port)
4291                 return NULL;
4292
4293         if (port->cached_edid)
4294                 edid = drm_edid_duplicate(port->cached_edid);
4295         else {
4296                 edid = drm_get_edid(connector, &port->aux.ddc);
4297         }
4298         port->has_audio = drm_detect_monitor_audio(edid);
4299         drm_dp_mst_topology_put_port(port);
4300         return edid;
4301 }
4302 EXPORT_SYMBOL(drm_dp_mst_get_edid);
4303
4304 /**
4305  * drm_dp_find_vcpi_slots() - Find VCPI slots for this PBN value
4306  * @mgr: manager to use
4307  * @pbn: payload bandwidth to convert into slots.
4308  *
4309  * Calculate the number of VCPI slots that will be required for the given PBN
4310  * value. This function is deprecated, and should not be used in atomic
4311  * drivers.
4312  *
4313  * RETURNS:
4314  * The total slots required for this port, or error.
4315  */
4316 int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
4317                            int pbn)
4318 {
4319         int num_slots;
4320
4321         num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
4322
4323         /* max. time slots - one slot for MTP header */
4324         if (num_slots > 63)
4325                 return -ENOSPC;
4326         return num_slots;
4327 }
4328 EXPORT_SYMBOL(drm_dp_find_vcpi_slots);
4329
4330 static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
4331                             struct drm_dp_vcpi *vcpi, int pbn, int slots)
4332 {
4333         int ret;
4334
4335         vcpi->pbn = pbn;
4336         vcpi->aligned_pbn = slots * mgr->pbn_div;
4337         vcpi->num_slots = slots;
4338
4339         ret = drm_dp_mst_assign_payload_id(mgr, vcpi);
4340         if (ret < 0)
4341                 return ret;
4342         return 0;
4343 }
4344
4345 /**
4346  * drm_dp_atomic_find_vcpi_slots() - Find and add VCPI slots to the state
4347  * @state: global atomic state
4348  * @mgr: MST topology manager for the port
4349  * @port: port to find vcpi slots for
4350  * @pbn: bandwidth required for the mode in PBN
4351  * @pbn_div: divider for DSC mode that takes FEC into account
4352  *
4353  * Allocates VCPI slots to @port, replacing any previous VCPI allocations it
4354  * may have had. Any atomic drivers which support MST must call this function
4355  * in their &drm_encoder_helper_funcs.atomic_check() callback to change the
4356  * current VCPI allocation for the new state, but only when
4357  * &drm_crtc_state.mode_changed or &drm_crtc_state.connectors_changed is set
4358  * to ensure compatibility with userspace applications that still use the
4359  * legacy modesetting UAPI.
4360  *
4361  * Allocations set by this function are not checked against the bandwidth
4362  * restraints of @mgr until the driver calls drm_dp_mst_atomic_check().
4363  *
4364  * Additionally, it is OK to call this function multiple times on the same
4365  * @port as needed. It is not OK however, to call this function and
4366  * drm_dp_atomic_release_vcpi_slots() in the same atomic check phase.
4367  *
4368  * See also:
4369  * drm_dp_atomic_release_vcpi_slots()
4370  * drm_dp_mst_atomic_check()
4371  *
4372  * Returns:
4373  * Total slots in the atomic state assigned for this port, or a negative error
4374  * code if the port no longer exists
4375  */
4376 int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
4377                                   struct drm_dp_mst_topology_mgr *mgr,
4378                                   struct drm_dp_mst_port *port, int pbn,
4379                                   int pbn_div)
4380 {
4381         struct drm_dp_mst_topology_state *topology_state;
4382         struct drm_dp_vcpi_allocation *pos, *vcpi = NULL;
4383         int prev_slots, prev_bw, req_slots;
4384
4385         topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4386         if (IS_ERR(topology_state))
4387                 return PTR_ERR(topology_state);
4388
4389         /* Find the current allocation for this port, if any */
4390         list_for_each_entry(pos, &topology_state->vcpis, next) {
4391                 if (pos->port == port) {
4392                         vcpi = pos;
4393                         prev_slots = vcpi->vcpi;
4394                         prev_bw = vcpi->pbn;
4395
4396                         /*
4397                          * This should never happen, unless the driver tries
4398                          * releasing and allocating the same VCPI allocation,
4399                          * which is an error
4400                          */
4401                         if (WARN_ON(!prev_slots)) {
4402                                 drm_err(mgr->dev,
4403                                         "cannot allocate and release VCPI on [MST PORT:%p] in the same state\n",
4404                                         port);
4405                                 return -EINVAL;
4406                         }
4407
4408                         break;
4409                 }
4410         }
4411         if (!vcpi) {
4412                 prev_slots = 0;
4413                 prev_bw = 0;
4414         }
4415
4416         if (pbn_div <= 0)
4417                 pbn_div = mgr->pbn_div;
4418
4419         req_slots = DIV_ROUND_UP(pbn, pbn_div);
4420
4421         drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] VCPI %d -> %d\n",
4422                        port->connector->base.id, port->connector->name,
4423                        port, prev_slots, req_slots);
4424         drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] PBN %d -> %d\n",
4425                        port->connector->base.id, port->connector->name,
4426                        port, prev_bw, pbn);
4427
4428         /* Add the new allocation to the state */
4429         if (!vcpi) {
4430                 vcpi = kzalloc(sizeof(*vcpi), GFP_KERNEL);
4431                 if (!vcpi)
4432                         return -ENOMEM;
4433
4434                 drm_dp_mst_get_port_malloc(port);
4435                 vcpi->port = port;
4436                 list_add(&vcpi->next, &topology_state->vcpis);
4437         }
4438         vcpi->vcpi = req_slots;
4439         vcpi->pbn = pbn;
4440
4441         return req_slots;
4442 }
4443 EXPORT_SYMBOL(drm_dp_atomic_find_vcpi_slots);
4444
4445 /**
4446  * drm_dp_atomic_release_vcpi_slots() - Release allocated vcpi slots
4447  * @state: global atomic state
4448  * @mgr: MST topology manager for the port
4449  * @port: The port to release the VCPI slots from
4450  *
4451  * Releases any VCPI slots that have been allocated to a port in the atomic
4452  * state. Any atomic drivers which support MST must call this function in
4453  * their &drm_connector_helper_funcs.atomic_check() callback when the
4454  * connector will no longer have VCPI allocated (e.g. because its CRTC was
4455  * removed) when it had VCPI allocated in the previous atomic state.
4456  *
4457  * It is OK to call this even if @port has been removed from the system.
4458  * Additionally, it is OK to call this function multiple times on the same
4459  * @port as needed. It is not OK however, to call this function and
4460  * drm_dp_atomic_find_vcpi_slots() on the same @port in a single atomic check
4461  * phase.
4462  *
4463  * See also:
4464  * drm_dp_atomic_find_vcpi_slots()
4465  * drm_dp_mst_atomic_check()
4466  *
4467  * Returns:
4468  * 0 if all slots for this port were added back to
4469  * &drm_dp_mst_topology_state.avail_slots or negative error code
4470  */
4471 int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
4472                                      struct drm_dp_mst_topology_mgr *mgr,
4473                                      struct drm_dp_mst_port *port)
4474 {
4475         struct drm_dp_mst_topology_state *topology_state;
4476         struct drm_dp_vcpi_allocation *pos;
4477         bool found = false;
4478
4479         topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4480         if (IS_ERR(topology_state))
4481                 return PTR_ERR(topology_state);
4482
4483         list_for_each_entry(pos, &topology_state->vcpis, next) {
4484                 if (pos->port == port) {
4485                         found = true;
4486                         break;
4487                 }
4488         }
4489         if (WARN_ON(!found)) {
4490                 drm_err(mgr->dev, "no VCPI for [MST PORT:%p] found in mst state %p\n",
4491                         port, &topology_state->base);
4492                 return -EINVAL;
4493         }
4494
4495         drm_dbg_atomic(mgr->dev, "[MST PORT:%p] VCPI %d -> 0\n", port, pos->vcpi);
4496         if (pos->vcpi) {
4497                 drm_dp_mst_put_port_malloc(port);
4498                 pos->vcpi = 0;
4499                 pos->pbn = 0;
4500         }
4501
4502         return 0;
4503 }
4504 EXPORT_SYMBOL(drm_dp_atomic_release_vcpi_slots);
4505
4506 /**
4507  * drm_dp_mst_update_slots() - updates the slot info depending on the DP ecoding format
4508  * @mst_state: mst_state to update
4509  * @link_encoding_cap: the ecoding format on the link
4510  */
4511 void drm_dp_mst_update_slots(struct drm_dp_mst_topology_state *mst_state, uint8_t link_encoding_cap)
4512 {
4513         if (link_encoding_cap == DP_CAP_ANSI_128B132B) {
4514                 mst_state->total_avail_slots = 64;
4515                 mst_state->start_slot = 0;
4516         } else {
4517                 mst_state->total_avail_slots = 63;
4518                 mst_state->start_slot = 1;
4519         }
4520
4521         DRM_DEBUG_KMS("%s encoding format on mst_state 0x%p\n",
4522                       (link_encoding_cap == DP_CAP_ANSI_128B132B) ? "128b/132b":"8b/10b",
4523                       mst_state);
4524 }
4525 EXPORT_SYMBOL(drm_dp_mst_update_slots);
4526
4527 /**
4528  * drm_dp_mst_allocate_vcpi() - Allocate a virtual channel
4529  * @mgr: manager for this port
4530  * @port: port to allocate a virtual channel for.
4531  * @pbn: payload bandwidth number to request
4532  * @slots: returned number of slots for this PBN.
4533  */
4534 bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
4535                               struct drm_dp_mst_port *port, int pbn, int slots)
4536 {
4537         int ret;
4538
4539         if (slots < 0)
4540                 return false;
4541
4542         port = drm_dp_mst_topology_get_port_validated(mgr, port);
4543         if (!port)
4544                 return false;
4545
4546         if (port->vcpi.vcpi > 0) {
4547                 drm_dbg_kms(mgr->dev,
4548                             "payload: vcpi %d already allocated for pbn %d - requested pbn %d\n",
4549                             port->vcpi.vcpi, port->vcpi.pbn, pbn);
4550                 if (pbn == port->vcpi.pbn) {
4551                         drm_dp_mst_topology_put_port(port);
4552                         return true;
4553                 }
4554         }
4555
4556         ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn, slots);
4557         if (ret) {
4558                 drm_dbg_kms(mgr->dev, "failed to init vcpi slots=%d ret=%d\n",
4559                             DIV_ROUND_UP(pbn, mgr->pbn_div), ret);
4560                 drm_dp_mst_topology_put_port(port);
4561                 goto out;
4562         }
4563         drm_dbg_kms(mgr->dev, "initing vcpi for pbn=%d slots=%d\n", pbn, port->vcpi.num_slots);
4564
4565         /* Keep port allocated until its payload has been removed */
4566         drm_dp_mst_get_port_malloc(port);
4567         drm_dp_mst_topology_put_port(port);
4568         return true;
4569 out:
4570         return false;
4571 }
4572 EXPORT_SYMBOL(drm_dp_mst_allocate_vcpi);
4573
4574 int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4575 {
4576         int slots = 0;
4577
4578         port = drm_dp_mst_topology_get_port_validated(mgr, port);
4579         if (!port)
4580                 return slots;
4581
4582         slots = port->vcpi.num_slots;
4583         drm_dp_mst_topology_put_port(port);
4584         return slots;
4585 }
4586 EXPORT_SYMBOL(drm_dp_mst_get_vcpi_slots);
4587
4588 /**
4589  * drm_dp_mst_reset_vcpi_slots() - Reset number of slots to 0 for VCPI
4590  * @mgr: manager for this port
4591  * @port: unverified pointer to a port.
4592  *
4593  * This just resets the number of slots for the ports VCPI for later programming.
4594  */
4595 void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4596 {
4597         /*
4598          * A port with VCPI will remain allocated until its VCPI is
4599          * released, no verified ref needed
4600          */
4601
4602         port->vcpi.num_slots = 0;
4603 }
4604 EXPORT_SYMBOL(drm_dp_mst_reset_vcpi_slots);
4605
4606 /**
4607  * drm_dp_mst_deallocate_vcpi() - deallocate a VCPI
4608  * @mgr: manager for this port
4609  * @port: port to deallocate vcpi for
4610  *
4611  * This can be called unconditionally, regardless of whether
4612  * drm_dp_mst_allocate_vcpi() succeeded or not.
4613  */
4614 void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
4615                                 struct drm_dp_mst_port *port)
4616 {
4617         bool skip;
4618
4619         if (!port->vcpi.vcpi)
4620                 return;
4621
4622         mutex_lock(&mgr->lock);
4623         skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
4624         mutex_unlock(&mgr->lock);
4625
4626         if (skip)
4627                 return;
4628
4629         drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
4630         port->vcpi.num_slots = 0;
4631         port->vcpi.pbn = 0;
4632         port->vcpi.aligned_pbn = 0;
4633         port->vcpi.vcpi = 0;
4634         drm_dp_mst_put_port_malloc(port);
4635 }
4636 EXPORT_SYMBOL(drm_dp_mst_deallocate_vcpi);
4637
4638 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
4639                                      int id, struct drm_dp_payload *payload)
4640 {
4641         u8 payload_alloc[3], status;
4642         int ret;
4643         int retries = 0;
4644
4645         drm_dp_dpcd_writeb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS,
4646                            DP_PAYLOAD_TABLE_UPDATED);
4647
4648         payload_alloc[0] = id;
4649         payload_alloc[1] = payload->start_slot;
4650         payload_alloc[2] = payload->num_slots;
4651
4652         ret = drm_dp_dpcd_write(mgr->aux, DP_PAYLOAD_ALLOCATE_SET, payload_alloc, 3);
4653         if (ret != 3) {
4654                 drm_dbg_kms(mgr->dev, "failed to write payload allocation %d\n", ret);
4655                 goto fail;
4656         }
4657
4658 retry:
4659         ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4660         if (ret < 0) {
4661                 drm_dbg_kms(mgr->dev, "failed to read payload table status %d\n", ret);
4662                 goto fail;
4663         }
4664
4665         if (!(status & DP_PAYLOAD_TABLE_UPDATED)) {
4666                 retries++;
4667                 if (retries < 20) {
4668                         usleep_range(10000, 20000);
4669                         goto retry;
4670                 }
4671                 drm_dbg_kms(mgr->dev, "status not set after read payload table status %d\n",
4672                             status);
4673                 ret = -EINVAL;
4674                 goto fail;
4675         }
4676         ret = 0;
4677 fail:
4678         return ret;
4679 }
4680
4681 static int do_get_act_status(struct drm_dp_aux *aux)
4682 {
4683         int ret;
4684         u8 status;
4685
4686         ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4687         if (ret < 0)
4688                 return ret;
4689
4690         return status;
4691 }
4692
4693 /**
4694  * drm_dp_check_act_status() - Polls for ACT handled status.
4695  * @mgr: manager to use
4696  *
4697  * Tries waiting for the MST hub to finish updating it's payload table by
4698  * polling for the ACT handled bit for up to 3 seconds (yes-some hubs really
4699  * take that long).
4700  *
4701  * Returns:
4702  * 0 if the ACT was handled in time, negative error code on failure.
4703  */
4704 int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
4705 {
4706         /*
4707          * There doesn't seem to be any recommended retry count or timeout in
4708          * the MST specification. Since some hubs have been observed to take
4709          * over 1 second to update their payload allocations under certain
4710          * conditions, we use a rather large timeout value.
4711          */
4712         const int timeout_ms = 3000;
4713         int ret, status;
4714
4715         ret = readx_poll_timeout(do_get_act_status, mgr->aux, status,
4716                                  status & DP_PAYLOAD_ACT_HANDLED || status < 0,
4717                                  200, timeout_ms * USEC_PER_MSEC);
4718         if (ret < 0 && status >= 0) {
4719                 drm_err(mgr->dev, "Failed to get ACT after %dms, last status: %02x\n",
4720                         timeout_ms, status);
4721                 return -EINVAL;
4722         } else if (status < 0) {
4723                 /*
4724                  * Failure here isn't unexpected - the hub may have
4725                  * just been unplugged
4726                  */
4727                 drm_dbg_kms(mgr->dev, "Failed to read payload table status: %d\n", status);
4728                 return status;
4729         }
4730
4731         return 0;
4732 }
4733 EXPORT_SYMBOL(drm_dp_check_act_status);
4734
4735 /**
4736  * drm_dp_calc_pbn_mode() - Calculate the PBN for a mode.
4737  * @clock: dot clock for the mode
4738  * @bpp: bpp for the mode.
4739  * @dsc: DSC mode. If true, bpp has units of 1/16 of a bit per pixel
4740  *
4741  * This uses the formula in the spec to calculate the PBN value for a mode.
4742  */
4743 int drm_dp_calc_pbn_mode(int clock, int bpp, bool dsc)
4744 {
4745         /*
4746          * margin 5300ppm + 300ppm ~ 0.6% as per spec, factor is 1.006
4747          * The unit of 54/64Mbytes/sec is an arbitrary unit chosen based on
4748          * common multiplier to render an integer PBN for all link rate/lane
4749          * counts combinations
4750          * calculate
4751          * peak_kbps *= (1006/1000)
4752          * peak_kbps *= (64/54)
4753          * peak_kbps *= 8    convert to bytes
4754          *
4755          * If the bpp is in units of 1/16, further divide by 16. Put this
4756          * factor in the numerator rather than the denominator to avoid
4757          * integer overflow
4758          */
4759
4760         if (dsc)
4761                 return DIV_ROUND_UP_ULL(mul_u32_u32(clock * (bpp / 16), 64 * 1006),
4762                                         8 * 54 * 1000 * 1000);
4763
4764         return DIV_ROUND_UP_ULL(mul_u32_u32(clock * bpp, 64 * 1006),
4765                                 8 * 54 * 1000 * 1000);
4766 }
4767 EXPORT_SYMBOL(drm_dp_calc_pbn_mode);
4768
4769 /* we want to kick the TX after we've ack the up/down IRQs. */
4770 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr)
4771 {
4772         queue_work(system_long_wq, &mgr->tx_work);
4773 }
4774
4775 /*
4776  * Helper function for parsing DP device types into convenient strings
4777  * for use with dp_mst_topology
4778  */
4779 static const char *pdt_to_string(u8 pdt)
4780 {
4781         switch (pdt) {
4782         case DP_PEER_DEVICE_NONE:
4783                 return "NONE";
4784         case DP_PEER_DEVICE_SOURCE_OR_SST:
4785                 return "SOURCE OR SST";
4786         case DP_PEER_DEVICE_MST_BRANCHING:
4787                 return "MST BRANCHING";
4788         case DP_PEER_DEVICE_SST_SINK:
4789                 return "SST SINK";
4790         case DP_PEER_DEVICE_DP_LEGACY_CONV:
4791                 return "DP LEGACY CONV";
4792         default:
4793                 return "ERR";
4794         }
4795 }
4796
4797 static void drm_dp_mst_dump_mstb(struct seq_file *m,
4798                                  struct drm_dp_mst_branch *mstb)
4799 {
4800         struct drm_dp_mst_port *port;
4801         int tabs = mstb->lct;
4802         char prefix[10];
4803         int i;
4804
4805         for (i = 0; i < tabs; i++)
4806                 prefix[i] = '\t';
4807         prefix[i] = '\0';
4808
4809         seq_printf(m, "%smstb - [%p]: num_ports: %d\n", prefix, mstb, mstb->num_ports);
4810         list_for_each_entry(port, &mstb->ports, next) {
4811                 seq_printf(m, "%sport %d - [%p] (%s - %s): ddps: %d, ldps: %d, sdp: %d/%d, fec: %s, conn: %p\n",
4812                            prefix,
4813                            port->port_num,
4814                            port,
4815                            port->input ? "input" : "output",
4816                            pdt_to_string(port->pdt),
4817                            port->ddps,
4818                            port->ldps,
4819                            port->num_sdp_streams,
4820                            port->num_sdp_stream_sinks,
4821                            port->fec_capable ? "true" : "false",
4822                            port->connector);
4823                 if (port->mstb)
4824                         drm_dp_mst_dump_mstb(m, port->mstb);
4825         }
4826 }
4827
4828 #define DP_PAYLOAD_TABLE_SIZE           64
4829
4830 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
4831                                   char *buf)
4832 {
4833         int i;
4834
4835         for (i = 0; i < DP_PAYLOAD_TABLE_SIZE; i += 16) {
4836                 if (drm_dp_dpcd_read(mgr->aux,
4837                                      DP_PAYLOAD_TABLE_UPDATE_STATUS + i,
4838                                      &buf[i], 16) != 16)
4839                         return false;
4840         }
4841         return true;
4842 }
4843
4844 static void fetch_monitor_name(struct drm_dp_mst_topology_mgr *mgr,
4845                                struct drm_dp_mst_port *port, char *name,
4846                                int namelen)
4847 {
4848         struct edid *mst_edid;
4849
4850         mst_edid = drm_dp_mst_get_edid(port->connector, mgr, port);
4851         drm_edid_get_monitor_name(mst_edid, name, namelen);
4852         kfree(mst_edid);
4853 }
4854
4855 /**
4856  * drm_dp_mst_dump_topology(): dump topology to seq file.
4857  * @m: seq_file to dump output to
4858  * @mgr: manager to dump current topology for.
4859  *
4860  * helper to dump MST topology to a seq file for debugfs.
4861  */
4862 void drm_dp_mst_dump_topology(struct seq_file *m,
4863                               struct drm_dp_mst_topology_mgr *mgr)
4864 {
4865         int i;
4866         struct drm_dp_mst_port *port;
4867
4868         mutex_lock(&mgr->lock);
4869         if (mgr->mst_primary)
4870                 drm_dp_mst_dump_mstb(m, mgr->mst_primary);
4871
4872         /* dump VCPIs */
4873         mutex_unlock(&mgr->lock);
4874
4875         mutex_lock(&mgr->payload_lock);
4876         seq_printf(m, "\n*** VCPI Info ***\n");
4877         seq_printf(m, "payload_mask: %lx, vcpi_mask: %lx, max_payloads: %d\n", mgr->payload_mask, mgr->vcpi_mask, mgr->max_payloads);
4878
4879         seq_printf(m, "\n|   idx   |  port # |  vcp_id | # slots |     sink name     |\n");
4880         for (i = 0; i < mgr->max_payloads; i++) {
4881                 if (mgr->proposed_vcpis[i]) {
4882                         char name[14];
4883
4884                         port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
4885                         fetch_monitor_name(mgr, port, name, sizeof(name));
4886                         seq_printf(m, "%10d%10d%10d%10d%20s\n",
4887                                    i,
4888                                    port->port_num,
4889                                    port->vcpi.vcpi,
4890                                    port->vcpi.num_slots,
4891                                    (*name != 0) ? name : "Unknown");
4892                 } else
4893                         seq_printf(m, "%6d - Unused\n", i);
4894         }
4895         seq_printf(m, "\n*** Payload Info ***\n");
4896         seq_printf(m, "|   idx   |  state  |  start slot  | # slots |\n");
4897         for (i = 0; i < mgr->max_payloads; i++) {
4898                 seq_printf(m, "%10d%10d%15d%10d\n",
4899                            i,
4900                            mgr->payloads[i].payload_state,
4901                            mgr->payloads[i].start_slot,
4902                            mgr->payloads[i].num_slots);
4903         }
4904         mutex_unlock(&mgr->payload_lock);
4905
4906         seq_printf(m, "\n*** DPCD Info ***\n");
4907         mutex_lock(&mgr->lock);
4908         if (mgr->mst_primary) {
4909                 u8 buf[DP_PAYLOAD_TABLE_SIZE];
4910                 int ret;
4911
4912                 if (drm_dp_read_dpcd_caps(mgr->aux, buf) < 0) {
4913                         seq_printf(m, "dpcd read failed\n");
4914                         goto out;
4915                 }
4916                 seq_printf(m, "dpcd: %*ph\n", DP_RECEIVER_CAP_SIZE, buf);
4917
4918                 ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2);
4919                 if (ret) {
4920                         seq_printf(m, "faux/mst read failed\n");
4921                         goto out;
4922                 }
4923                 seq_printf(m, "faux/mst: %*ph\n", 2, buf);
4924
4925                 ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1);
4926                 if (ret) {
4927                         seq_printf(m, "mst ctrl read failed\n");
4928                         goto out;
4929                 }
4930                 seq_printf(m, "mst ctrl: %*ph\n", 1, buf);
4931
4932                 /* dump the standard OUI branch header */
4933                 ret = drm_dp_dpcd_read(mgr->aux, DP_BRANCH_OUI, buf, DP_BRANCH_OUI_HEADER_SIZE);
4934                 if (ret) {
4935                         seq_printf(m, "branch oui read failed\n");
4936                         goto out;
4937                 }
4938                 seq_printf(m, "branch oui: %*phN devid: ", 3, buf);
4939
4940                 for (i = 0x3; i < 0x8 && buf[i]; i++)
4941                         seq_printf(m, "%c", buf[i]);
4942                 seq_printf(m, " revision: hw: %x.%x sw: %x.%x\n",
4943                            buf[0x9] >> 4, buf[0x9] & 0xf, buf[0xa], buf[0xb]);
4944                 if (dump_dp_payload_table(mgr, buf))
4945                         seq_printf(m, "payload table: %*ph\n", DP_PAYLOAD_TABLE_SIZE, buf);
4946         }
4947
4948 out:
4949         mutex_unlock(&mgr->lock);
4950
4951 }
4952 EXPORT_SYMBOL(drm_dp_mst_dump_topology);
4953
4954 static void drm_dp_tx_work(struct work_struct *work)
4955 {
4956         struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, tx_work);
4957
4958         mutex_lock(&mgr->qlock);
4959         if (!list_empty(&mgr->tx_msg_downq))
4960                 process_single_down_tx_qlock(mgr);
4961         mutex_unlock(&mgr->qlock);
4962 }
4963
4964 static inline void
4965 drm_dp_delayed_destroy_port(struct drm_dp_mst_port *port)
4966 {
4967         drm_dp_port_set_pdt(port, DP_PEER_DEVICE_NONE, port->mcs);
4968
4969         if (port->connector) {
4970                 drm_connector_unregister(port->connector);
4971                 drm_connector_put(port->connector);
4972         }
4973
4974         drm_dp_mst_put_port_malloc(port);
4975 }
4976
4977 static inline void
4978 drm_dp_delayed_destroy_mstb(struct drm_dp_mst_branch *mstb)
4979 {
4980         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
4981         struct drm_dp_mst_port *port, *port_tmp;
4982         struct drm_dp_sideband_msg_tx *txmsg, *txmsg_tmp;
4983         bool wake_tx = false;
4984
4985         mutex_lock(&mgr->lock);
4986         list_for_each_entry_safe(port, port_tmp, &mstb->ports, next) {
4987                 list_del(&port->next);
4988                 drm_dp_mst_topology_put_port(port);
4989         }
4990         mutex_unlock(&mgr->lock);
4991
4992         /* drop any tx slot msg */
4993         mutex_lock(&mstb->mgr->qlock);
4994         list_for_each_entry_safe(txmsg, txmsg_tmp, &mgr->tx_msg_downq, next) {
4995                 if (txmsg->dst != mstb)
4996                         continue;
4997
4998                 txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
4999                 list_del(&txmsg->next);
5000                 wake_tx = true;
5001         }
5002         mutex_unlock(&mstb->mgr->qlock);
5003
5004         if (wake_tx)
5005                 wake_up_all(&mstb->mgr->tx_waitq);
5006
5007         drm_dp_mst_put_mstb_malloc(mstb);
5008 }
5009
5010 static void drm_dp_delayed_destroy_work(struct work_struct *work)
5011 {
5012         struct drm_dp_mst_topology_mgr *mgr =
5013                 container_of(work, struct drm_dp_mst_topology_mgr,
5014                              delayed_destroy_work);
5015         bool send_hotplug = false, go_again;
5016
5017         /*
5018          * Not a regular list traverse as we have to drop the destroy
5019          * connector lock before destroying the mstb/port, to avoid AB->BA
5020          * ordering between this lock and the config mutex.
5021          */
5022         do {
5023                 go_again = false;
5024
5025                 for (;;) {
5026                         struct drm_dp_mst_branch *mstb;
5027
5028                         mutex_lock(&mgr->delayed_destroy_lock);
5029                         mstb = list_first_entry_or_null(&mgr->destroy_branch_device_list,
5030                                                         struct drm_dp_mst_branch,
5031                                                         destroy_next);
5032                         if (mstb)
5033                                 list_del(&mstb->destroy_next);
5034                         mutex_unlock(&mgr->delayed_destroy_lock);
5035
5036                         if (!mstb)
5037                                 break;
5038
5039                         drm_dp_delayed_destroy_mstb(mstb);
5040                         go_again = true;
5041                 }
5042
5043                 for (;;) {
5044                         struct drm_dp_mst_port *port;
5045
5046                         mutex_lock(&mgr->delayed_destroy_lock);
5047                         port = list_first_entry_or_null(&mgr->destroy_port_list,
5048                                                         struct drm_dp_mst_port,
5049                                                         next);
5050                         if (port)
5051                                 list_del(&port->next);
5052                         mutex_unlock(&mgr->delayed_destroy_lock);
5053
5054                         if (!port)
5055                                 break;
5056
5057                         drm_dp_delayed_destroy_port(port);
5058                         send_hotplug = true;
5059                         go_again = true;
5060                 }
5061         } while (go_again);
5062
5063         if (send_hotplug)
5064                 drm_kms_helper_hotplug_event(mgr->dev);
5065 }
5066
5067 static struct drm_private_state *
5068 drm_dp_mst_duplicate_state(struct drm_private_obj *obj)
5069 {
5070         struct drm_dp_mst_topology_state *state, *old_state =
5071                 to_dp_mst_topology_state(obj->state);
5072         struct drm_dp_vcpi_allocation *pos, *vcpi;
5073
5074         state = kmemdup(old_state, sizeof(*state), GFP_KERNEL);
5075         if (!state)
5076                 return NULL;
5077
5078         __drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);
5079
5080         INIT_LIST_HEAD(&state->vcpis);
5081
5082         list_for_each_entry(pos, &old_state->vcpis, next) {
5083                 /* Prune leftover freed VCPI allocations */
5084                 if (!pos->vcpi)
5085                         continue;
5086
5087                 vcpi = kmemdup(pos, sizeof(*vcpi), GFP_KERNEL);
5088                 if (!vcpi)
5089                         goto fail;
5090
5091                 drm_dp_mst_get_port_malloc(vcpi->port);
5092                 list_add(&vcpi->next, &state->vcpis);
5093         }
5094
5095         return &state->base;
5096
5097 fail:
5098         list_for_each_entry_safe(pos, vcpi, &state->vcpis, next) {
5099                 drm_dp_mst_put_port_malloc(pos->port);
5100                 kfree(pos);
5101         }
5102         kfree(state);
5103
5104         return NULL;
5105 }
5106
5107 static void drm_dp_mst_destroy_state(struct drm_private_obj *obj,
5108                                      struct drm_private_state *state)
5109 {
5110         struct drm_dp_mst_topology_state *mst_state =
5111                 to_dp_mst_topology_state(state);
5112         struct drm_dp_vcpi_allocation *pos, *tmp;
5113
5114         list_for_each_entry_safe(pos, tmp, &mst_state->vcpis, next) {
5115                 /* We only keep references to ports with non-zero VCPIs */
5116                 if (pos->vcpi)
5117                         drm_dp_mst_put_port_malloc(pos->port);
5118                 kfree(pos);
5119         }
5120
5121         kfree(mst_state);
5122 }
5123
5124 static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
5125                                                  struct drm_dp_mst_branch *branch)
5126 {
5127         while (port->parent) {
5128                 if (port->parent == branch)
5129                         return true;
5130
5131                 if (port->parent->port_parent)
5132                         port = port->parent->port_parent;
5133                 else
5134                         break;
5135         }
5136         return false;
5137 }
5138
5139 static int
5140 drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
5141                                       struct drm_dp_mst_topology_state *state);
5142
5143 static int
5144 drm_dp_mst_atomic_check_mstb_bw_limit(struct drm_dp_mst_branch *mstb,
5145                                       struct drm_dp_mst_topology_state *state)
5146 {
5147         struct drm_dp_vcpi_allocation *vcpi;
5148         struct drm_dp_mst_port *port;
5149         int pbn_used = 0, ret;
5150         bool found = false;
5151
5152         /* Check that we have at least one port in our state that's downstream
5153          * of this branch, otherwise we can skip this branch
5154          */
5155         list_for_each_entry(vcpi, &state->vcpis, next) {
5156                 if (!vcpi->pbn ||
5157                     !drm_dp_mst_port_downstream_of_branch(vcpi->port, mstb))
5158                         continue;
5159
5160                 found = true;
5161                 break;
5162         }
5163         if (!found)
5164                 return 0;
5165
5166         if (mstb->port_parent)
5167                 drm_dbg_atomic(mstb->mgr->dev,
5168                                "[MSTB:%p] [MST PORT:%p] Checking bandwidth limits on [MSTB:%p]\n",
5169                                mstb->port_parent->parent, mstb->port_parent, mstb);
5170         else
5171                 drm_dbg_atomic(mstb->mgr->dev, "[MSTB:%p] Checking bandwidth limits\n", mstb);
5172
5173         list_for_each_entry(port, &mstb->ports, next) {
5174                 ret = drm_dp_mst_atomic_check_port_bw_limit(port, state);
5175                 if (ret < 0)
5176                         return ret;
5177
5178                 pbn_used += ret;
5179         }
5180
5181         return pbn_used;
5182 }
5183
5184 static int
5185 drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
5186                                       struct drm_dp_mst_topology_state *state)
5187 {
5188         struct drm_dp_vcpi_allocation *vcpi;
5189         int pbn_used = 0;
5190
5191         if (port->pdt == DP_PEER_DEVICE_NONE)
5192                 return 0;
5193
5194         if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
5195                 bool found = false;
5196
5197                 list_for_each_entry(vcpi, &state->vcpis, next) {
5198                         if (vcpi->port != port)
5199                                 continue;
5200                         if (!vcpi->pbn)
5201                                 return 0;
5202
5203                         found = true;
5204                         break;
5205                 }
5206                 if (!found)
5207                         return 0;
5208
5209                 /*
5210                  * This could happen if the sink deasserted its HPD line, but
5211                  * the branch device still reports it as attached (PDT != NONE).
5212                  */
5213                 if (!port->full_pbn) {
5214                         drm_dbg_atomic(port->mgr->dev,
5215                                        "[MSTB:%p] [MST PORT:%p] no BW available for the port\n",
5216                                        port->parent, port);
5217                         return -EINVAL;
5218                 }
5219
5220                 pbn_used = vcpi->pbn;
5221         } else {
5222                 pbn_used = drm_dp_mst_atomic_check_mstb_bw_limit(port->mstb,
5223                                                                  state);
5224                 if (pbn_used <= 0)
5225                         return pbn_used;
5226         }
5227
5228         if (pbn_used > port->full_pbn) {
5229                 drm_dbg_atomic(port->mgr->dev,
5230                                "[MSTB:%p] [MST PORT:%p] required PBN of %d exceeds port limit of %d\n",
5231                                port->parent, port, pbn_used, port->full_pbn);
5232                 return -ENOSPC;
5233         }
5234
5235         drm_dbg_atomic(port->mgr->dev, "[MSTB:%p] [MST PORT:%p] uses %d out of %d PBN\n",
5236                        port->parent, port, pbn_used, port->full_pbn);
5237
5238         return pbn_used;
5239 }
5240
5241 static inline int
5242 drm_dp_mst_atomic_check_vcpi_alloc_limit(struct drm_dp_mst_topology_mgr *mgr,
5243                                          struct drm_dp_mst_topology_state *mst_state)
5244 {
5245         struct drm_dp_vcpi_allocation *vcpi;
5246         int avail_slots = mst_state->total_avail_slots, payload_count = 0;
5247
5248         list_for_each_entry(vcpi, &mst_state->vcpis, next) {
5249                 /* Releasing VCPI is always OK-even if the port is gone */
5250                 if (!vcpi->vcpi) {
5251                         drm_dbg_atomic(mgr->dev, "[MST PORT:%p] releases all VCPI slots\n",
5252                                        vcpi->port);
5253                         continue;
5254                 }
5255
5256                 drm_dbg_atomic(mgr->dev, "[MST PORT:%p] requires %d vcpi slots\n",
5257                                vcpi->port, vcpi->vcpi);
5258
5259                 avail_slots -= vcpi->vcpi;
5260                 if (avail_slots < 0) {
5261                         drm_dbg_atomic(mgr->dev,
5262                                        "[MST PORT:%p] not enough VCPI slots in mst state %p (avail=%d)\n",
5263                                        vcpi->port, mst_state, avail_slots + vcpi->vcpi);
5264                         return -ENOSPC;
5265                 }
5266
5267                 if (++payload_count > mgr->max_payloads) {
5268                         drm_dbg_atomic(mgr->dev,
5269                                        "[MST MGR:%p] state %p has too many payloads (max=%d)\n",
5270                                        mgr, mst_state, mgr->max_payloads);
5271                         return -EINVAL;
5272                 }
5273         }
5274         drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p VCPI avail=%d used=%d\n",
5275                        mgr, mst_state, avail_slots, mst_state->total_avail_slots - avail_slots);
5276
5277         return 0;
5278 }
5279
5280 /**
5281  * drm_dp_mst_add_affected_dsc_crtcs
5282  * @state: Pointer to the new struct drm_dp_mst_topology_state
5283  * @mgr: MST topology manager
5284  *
5285  * Whenever there is a change in mst topology
5286  * DSC configuration would have to be recalculated
5287  * therefore we need to trigger modeset on all affected
5288  * CRTCs in that topology
5289  *
5290  * See also:
5291  * drm_dp_mst_atomic_enable_dsc()
5292  */
5293 int drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state, struct drm_dp_mst_topology_mgr *mgr)
5294 {
5295         struct drm_dp_mst_topology_state *mst_state;
5296         struct drm_dp_vcpi_allocation *pos;
5297         struct drm_connector *connector;
5298         struct drm_connector_state *conn_state;
5299         struct drm_crtc *crtc;
5300         struct drm_crtc_state *crtc_state;
5301
5302         mst_state = drm_atomic_get_mst_topology_state(state, mgr);
5303
5304         if (IS_ERR(mst_state))
5305                 return -EINVAL;
5306
5307         list_for_each_entry(pos, &mst_state->vcpis, next) {
5308
5309                 connector = pos->port->connector;
5310
5311                 if (!connector)
5312                         return -EINVAL;
5313
5314                 conn_state = drm_atomic_get_connector_state(state, connector);
5315
5316                 if (IS_ERR(conn_state))
5317                         return PTR_ERR(conn_state);
5318
5319                 crtc = conn_state->crtc;
5320
5321                 if (!crtc)
5322                         continue;
5323
5324                 if (!drm_dp_mst_dsc_aux_for_port(pos->port))
5325                         continue;
5326
5327                 crtc_state = drm_atomic_get_crtc_state(mst_state->base.state, crtc);
5328
5329                 if (IS_ERR(crtc_state))
5330                         return PTR_ERR(crtc_state);
5331
5332                 drm_dbg_atomic(mgr->dev, "[MST MGR:%p] Setting mode_changed flag on CRTC %p\n",
5333                                mgr, crtc);
5334
5335                 crtc_state->mode_changed = true;
5336         }
5337         return 0;
5338 }
5339 EXPORT_SYMBOL(drm_dp_mst_add_affected_dsc_crtcs);
5340
5341 /**
5342  * drm_dp_mst_atomic_enable_dsc - Set DSC Enable Flag to On/Off
5343  * @state: Pointer to the new drm_atomic_state
5344  * @port: Pointer to the affected MST Port
5345  * @pbn: Newly recalculated bw required for link with DSC enabled
5346  * @pbn_div: Divider to calculate correct number of pbn per slot
5347  * @enable: Boolean flag to enable or disable DSC on the port
5348  *
5349  * This function enables DSC on the given Port
5350  * by recalculating its vcpi from pbn provided
5351  * and sets dsc_enable flag to keep track of which
5352  * ports have DSC enabled
5353  *
5354  */
5355 int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
5356                                  struct drm_dp_mst_port *port,
5357                                  int pbn, int pbn_div,
5358                                  bool enable)
5359 {
5360         struct drm_dp_mst_topology_state *mst_state;
5361         struct drm_dp_vcpi_allocation *pos;
5362         bool found = false;
5363         int vcpi = 0;
5364
5365         mst_state = drm_atomic_get_mst_topology_state(state, port->mgr);
5366
5367         if (IS_ERR(mst_state))
5368                 return PTR_ERR(mst_state);
5369
5370         list_for_each_entry(pos, &mst_state->vcpis, next) {
5371                 if (pos->port == port) {
5372                         found = true;
5373                         break;
5374                 }
5375         }
5376
5377         if (!found) {
5378                 drm_dbg_atomic(state->dev,
5379                                "[MST PORT:%p] Couldn't find VCPI allocation in mst state %p\n",
5380                                port, mst_state);
5381                 return -EINVAL;
5382         }
5383
5384         if (pos->dsc_enabled == enable) {
5385                 drm_dbg_atomic(state->dev,
5386                                "[MST PORT:%p] DSC flag is already set to %d, returning %d VCPI slots\n",
5387                                port, enable, pos->vcpi);
5388                 vcpi = pos->vcpi;
5389         }
5390
5391         if (enable) {
5392                 vcpi = drm_dp_atomic_find_vcpi_slots(state, port->mgr, port, pbn, pbn_div);
5393                 drm_dbg_atomic(state->dev,
5394                                "[MST PORT:%p] Enabling DSC flag, reallocating %d VCPI slots on the port\n",
5395                                port, vcpi);
5396                 if (vcpi < 0)
5397                         return -EINVAL;
5398         }
5399
5400         pos->dsc_enabled = enable;
5401
5402         return vcpi;
5403 }
5404 EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc);
5405 /**
5406  * drm_dp_mst_atomic_check - Check that the new state of an MST topology in an
5407  * atomic update is valid
5408  * @state: Pointer to the new &struct drm_dp_mst_topology_state
5409  *
5410  * Checks the given topology state for an atomic update to ensure that it's
5411  * valid. This includes checking whether there's enough bandwidth to support
5412  * the new VCPI allocations in the atomic update.
5413  *
5414  * Any atomic drivers supporting DP MST must make sure to call this after
5415  * checking the rest of their state in their
5416  * &drm_mode_config_funcs.atomic_check() callback.
5417  *
5418  * See also:
5419  * drm_dp_atomic_find_vcpi_slots()
5420  * drm_dp_atomic_release_vcpi_slots()
5421  *
5422  * Returns:
5423  *
5424  * 0 if the new state is valid, negative error code otherwise.
5425  */
5426 int drm_dp_mst_atomic_check(struct drm_atomic_state *state)
5427 {
5428         struct drm_dp_mst_topology_mgr *mgr;
5429         struct drm_dp_mst_topology_state *mst_state;
5430         int i, ret = 0;
5431
5432         for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
5433                 if (!mgr->mst_state)
5434                         continue;
5435
5436                 ret = drm_dp_mst_atomic_check_vcpi_alloc_limit(mgr, mst_state);
5437                 if (ret)
5438                         break;
5439
5440                 mutex_lock(&mgr->lock);
5441                 ret = drm_dp_mst_atomic_check_mstb_bw_limit(mgr->mst_primary,
5442                                                             mst_state);
5443                 mutex_unlock(&mgr->lock);
5444                 if (ret < 0)
5445                         break;
5446                 else
5447                         ret = 0;
5448         }
5449
5450         return ret;
5451 }
5452 EXPORT_SYMBOL(drm_dp_mst_atomic_check);
5453
5454 const struct drm_private_state_funcs drm_dp_mst_topology_state_funcs = {
5455         .atomic_duplicate_state = drm_dp_mst_duplicate_state,
5456         .atomic_destroy_state = drm_dp_mst_destroy_state,
5457 };
5458 EXPORT_SYMBOL(drm_dp_mst_topology_state_funcs);
5459
5460 /**
5461  * drm_atomic_get_mst_topology_state: get MST topology state
5462  *
5463  * @state: global atomic state
5464  * @mgr: MST topology manager, also the private object in this case
5465  *
5466  * This function wraps drm_atomic_get_priv_obj_state() passing in the MST atomic
5467  * state vtable so that the private object state returned is that of a MST
5468  * topology object. Also, drm_atomic_get_private_obj_state() expects the caller
5469  * to care of the locking, so warn if don't hold the connection_mutex.
5470  *
5471  * RETURNS:
5472  *
5473  * The MST topology state or error pointer.
5474  */
5475 struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
5476                                                                     struct drm_dp_mst_topology_mgr *mgr)
5477 {
5478         return to_dp_mst_topology_state(drm_atomic_get_private_obj_state(state, &mgr->base));
5479 }
5480 EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
5481
5482 /**
5483  * drm_dp_mst_topology_mgr_init - initialise a topology manager
5484  * @mgr: manager struct to initialise
5485  * @dev: device providing this structure - for i2c addition.
5486  * @aux: DP helper aux channel to talk to this device
5487  * @max_dpcd_transaction_bytes: hw specific DPCD transaction limit
5488  * @max_payloads: maximum number of payloads this GPU can source
5489  * @max_lane_count: maximum number of lanes this GPU supports
5490  * @max_link_rate: maximum link rate per lane this GPU supports in kHz
5491  * @conn_base_id: the connector object ID the MST device is connected to.
5492  *
5493  * Return 0 for success, or negative error code on failure
5494  */
5495 int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
5496                                  struct drm_device *dev, struct drm_dp_aux *aux,
5497                                  int max_dpcd_transaction_bytes, int max_payloads,
5498                                  int max_lane_count, int max_link_rate,
5499                                  int conn_base_id)
5500 {
5501         struct drm_dp_mst_topology_state *mst_state;
5502
5503         mutex_init(&mgr->lock);
5504         mutex_init(&mgr->qlock);
5505         mutex_init(&mgr->payload_lock);
5506         mutex_init(&mgr->delayed_destroy_lock);
5507         mutex_init(&mgr->up_req_lock);
5508         mutex_init(&mgr->probe_lock);
5509 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5510         mutex_init(&mgr->topology_ref_history_lock);
5511         stack_depot_init();
5512 #endif
5513         INIT_LIST_HEAD(&mgr->tx_msg_downq);
5514         INIT_LIST_HEAD(&mgr->destroy_port_list);
5515         INIT_LIST_HEAD(&mgr->destroy_branch_device_list);
5516         INIT_LIST_HEAD(&mgr->up_req_list);
5517
5518         /*
5519          * delayed_destroy_work will be queued on a dedicated WQ, so that any
5520          * requeuing will be also flushed when deiniting the topology manager.
5521          */
5522         mgr->delayed_destroy_wq = alloc_ordered_workqueue("drm_dp_mst_wq", 0);
5523         if (mgr->delayed_destroy_wq == NULL)
5524                 return -ENOMEM;
5525
5526         INIT_WORK(&mgr->work, drm_dp_mst_link_probe_work);
5527         INIT_WORK(&mgr->tx_work, drm_dp_tx_work);
5528         INIT_WORK(&mgr->delayed_destroy_work, drm_dp_delayed_destroy_work);
5529         INIT_WORK(&mgr->up_req_work, drm_dp_mst_up_req_work);
5530         init_waitqueue_head(&mgr->tx_waitq);
5531         mgr->dev = dev;
5532         mgr->aux = aux;
5533         mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes;
5534         mgr->max_payloads = max_payloads;
5535         mgr->max_lane_count = max_lane_count;
5536         mgr->max_link_rate = max_link_rate;
5537         mgr->conn_base_id = conn_base_id;
5538         if (max_payloads + 1 > sizeof(mgr->payload_mask) * 8 ||
5539             max_payloads + 1 > sizeof(mgr->vcpi_mask) * 8)
5540                 return -EINVAL;
5541         mgr->payloads = kcalloc(max_payloads, sizeof(struct drm_dp_payload), GFP_KERNEL);
5542         if (!mgr->payloads)
5543                 return -ENOMEM;
5544         mgr->proposed_vcpis = kcalloc(max_payloads, sizeof(struct drm_dp_vcpi *), GFP_KERNEL);
5545         if (!mgr->proposed_vcpis)
5546                 return -ENOMEM;
5547         set_bit(0, &mgr->payload_mask);
5548
5549         mst_state = kzalloc(sizeof(*mst_state), GFP_KERNEL);
5550         if (mst_state == NULL)
5551                 return -ENOMEM;
5552
5553         mst_state->total_avail_slots = 63;
5554         mst_state->start_slot = 1;
5555
5556         mst_state->mgr = mgr;
5557         INIT_LIST_HEAD(&mst_state->vcpis);
5558
5559         drm_atomic_private_obj_init(dev, &mgr->base,
5560                                     &mst_state->base,
5561                                     &drm_dp_mst_topology_state_funcs);
5562
5563         return 0;
5564 }
5565 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_init);
5566
5567 /**
5568  * drm_dp_mst_topology_mgr_destroy() - destroy topology manager.
5569  * @mgr: manager to destroy
5570  */
5571 void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
5572 {
5573         drm_dp_mst_topology_mgr_set_mst(mgr, false);
5574         flush_work(&mgr->work);
5575         /* The following will also drain any requeued work on the WQ. */
5576         if (mgr->delayed_destroy_wq) {
5577                 destroy_workqueue(mgr->delayed_destroy_wq);
5578                 mgr->delayed_destroy_wq = NULL;
5579         }
5580         mutex_lock(&mgr->payload_lock);
5581         kfree(mgr->payloads);
5582         mgr->payloads = NULL;
5583         kfree(mgr->proposed_vcpis);
5584         mgr->proposed_vcpis = NULL;
5585         mutex_unlock(&mgr->payload_lock);
5586         mgr->dev = NULL;
5587         mgr->aux = NULL;
5588         drm_atomic_private_obj_fini(&mgr->base);
5589         mgr->funcs = NULL;
5590
5591         mutex_destroy(&mgr->delayed_destroy_lock);
5592         mutex_destroy(&mgr->payload_lock);
5593         mutex_destroy(&mgr->qlock);
5594         mutex_destroy(&mgr->lock);
5595         mutex_destroy(&mgr->up_req_lock);
5596         mutex_destroy(&mgr->probe_lock);
5597 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5598         mutex_destroy(&mgr->topology_ref_history_lock);
5599 #endif
5600 }
5601 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy);
5602
5603 static bool remote_i2c_read_ok(const struct i2c_msg msgs[], int num)
5604 {
5605         int i;
5606
5607         if (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS)
5608                 return false;
5609
5610         for (i = 0; i < num - 1; i++) {
5611                 if (msgs[i].flags & I2C_M_RD ||
5612                     msgs[i].len > 0xff)
5613                         return false;
5614         }
5615
5616         return msgs[num - 1].flags & I2C_M_RD &&
5617                 msgs[num - 1].len <= 0xff;
5618 }
5619
5620 static bool remote_i2c_write_ok(const struct i2c_msg msgs[], int num)
5621 {
5622         int i;
5623
5624         for (i = 0; i < num - 1; i++) {
5625                 if (msgs[i].flags & I2C_M_RD || !(msgs[i].flags & I2C_M_STOP) ||
5626                     msgs[i].len > 0xff)
5627                         return false;
5628         }
5629
5630         return !(msgs[num - 1].flags & I2C_M_RD) && msgs[num - 1].len <= 0xff;
5631 }
5632
5633 static int drm_dp_mst_i2c_read(struct drm_dp_mst_branch *mstb,
5634                                struct drm_dp_mst_port *port,
5635                                struct i2c_msg *msgs, int num)
5636 {
5637         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5638         unsigned int i;
5639         struct drm_dp_sideband_msg_req_body msg;
5640         struct drm_dp_sideband_msg_tx *txmsg = NULL;
5641         int ret;
5642
5643         memset(&msg, 0, sizeof(msg));
5644         msg.req_type = DP_REMOTE_I2C_READ;
5645         msg.u.i2c_read.num_transactions = num - 1;
5646         msg.u.i2c_read.port_number = port->port_num;
5647         for (i = 0; i < num - 1; i++) {
5648                 msg.u.i2c_read.transactions[i].i2c_dev_id = msgs[i].addr;
5649                 msg.u.i2c_read.transactions[i].num_bytes = msgs[i].len;
5650                 msg.u.i2c_read.transactions[i].bytes = msgs[i].buf;
5651                 msg.u.i2c_read.transactions[i].no_stop_bit = !(msgs[i].flags & I2C_M_STOP);
5652         }
5653         msg.u.i2c_read.read_i2c_device_id = msgs[num - 1].addr;
5654         msg.u.i2c_read.num_bytes_read = msgs[num - 1].len;
5655
5656         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5657         if (!txmsg) {
5658                 ret = -ENOMEM;
5659                 goto out;
5660         }
5661
5662         txmsg->dst = mstb;
5663         drm_dp_encode_sideband_req(&msg, txmsg);
5664
5665         drm_dp_queue_down_tx(mgr, txmsg);
5666
5667         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5668         if (ret > 0) {
5669
5670                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5671                         ret = -EREMOTEIO;
5672                         goto out;
5673                 }
5674                 if (txmsg->reply.u.remote_i2c_read_ack.num_bytes != msgs[num - 1].len) {
5675                         ret = -EIO;
5676                         goto out;
5677                 }
5678                 memcpy(msgs[num - 1].buf, txmsg->reply.u.remote_i2c_read_ack.bytes, msgs[num - 1].len);
5679                 ret = num;
5680         }
5681 out:
5682         kfree(txmsg);
5683         return ret;
5684 }
5685
5686 static int drm_dp_mst_i2c_write(struct drm_dp_mst_branch *mstb,
5687                                 struct drm_dp_mst_port *port,
5688                                 struct i2c_msg *msgs, int num)
5689 {
5690         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5691         unsigned int i;
5692         struct drm_dp_sideband_msg_req_body msg;
5693         struct drm_dp_sideband_msg_tx *txmsg = NULL;
5694         int ret;
5695
5696         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5697         if (!txmsg) {
5698                 ret = -ENOMEM;
5699                 goto out;
5700         }
5701         for (i = 0; i < num; i++) {
5702                 memset(&msg, 0, sizeof(msg));
5703                 msg.req_type = DP_REMOTE_I2C_WRITE;
5704                 msg.u.i2c_write.port_number = port->port_num;
5705                 msg.u.i2c_write.write_i2c_device_id = msgs[i].addr;
5706                 msg.u.i2c_write.num_bytes = msgs[i].len;
5707                 msg.u.i2c_write.bytes = msgs[i].buf;
5708
5709                 memset(txmsg, 0, sizeof(*txmsg));
5710                 txmsg->dst = mstb;
5711
5712                 drm_dp_encode_sideband_req(&msg, txmsg);
5713                 drm_dp_queue_down_tx(mgr, txmsg);
5714
5715                 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5716                 if (ret > 0) {
5717                         if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5718                                 ret = -EREMOTEIO;
5719                                 goto out;
5720                         }
5721                 } else {
5722                         goto out;
5723                 }
5724         }
5725         ret = num;
5726 out:
5727         kfree(txmsg);
5728         return ret;
5729 }
5730
5731 /* I2C device */
5732 static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter,
5733                                struct i2c_msg *msgs, int num)
5734 {
5735         struct drm_dp_aux *aux = adapter->algo_data;
5736         struct drm_dp_mst_port *port =
5737                 container_of(aux, struct drm_dp_mst_port, aux);
5738         struct drm_dp_mst_branch *mstb;
5739         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5740         int ret;
5741
5742         mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
5743         if (!mstb)
5744                 return -EREMOTEIO;
5745
5746         if (remote_i2c_read_ok(msgs, num)) {
5747                 ret = drm_dp_mst_i2c_read(mstb, port, msgs, num);
5748         } else if (remote_i2c_write_ok(msgs, num)) {
5749                 ret = drm_dp_mst_i2c_write(mstb, port, msgs, num);
5750         } else {
5751                 drm_dbg_kms(mgr->dev, "Unsupported I2C transaction for MST device\n");
5752                 ret = -EIO;
5753         }
5754
5755         drm_dp_mst_topology_put_mstb(mstb);
5756         return ret;
5757 }
5758
5759 static u32 drm_dp_mst_i2c_functionality(struct i2c_adapter *adapter)
5760 {
5761         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
5762                I2C_FUNC_SMBUS_READ_BLOCK_DATA |
5763                I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
5764                I2C_FUNC_10BIT_ADDR;
5765 }
5766
5767 static const struct i2c_algorithm drm_dp_mst_i2c_algo = {
5768         .functionality = drm_dp_mst_i2c_functionality,
5769         .master_xfer = drm_dp_mst_i2c_xfer,
5770 };
5771
5772 /**
5773  * drm_dp_mst_register_i2c_bus() - register an I2C adapter for I2C-over-AUX
5774  * @port: The port to add the I2C bus on
5775  *
5776  * Returns 0 on success or a negative error code on failure.
5777  */
5778 static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port)
5779 {
5780         struct drm_dp_aux *aux = &port->aux;
5781         struct device *parent_dev = port->mgr->dev->dev;
5782
5783         aux->ddc.algo = &drm_dp_mst_i2c_algo;
5784         aux->ddc.algo_data = aux;
5785         aux->ddc.retries = 3;
5786
5787         aux->ddc.class = I2C_CLASS_DDC;
5788         aux->ddc.owner = THIS_MODULE;
5789         /* FIXME: set the kdev of the port's connector as parent */
5790         aux->ddc.dev.parent = parent_dev;
5791         aux->ddc.dev.of_node = parent_dev->of_node;
5792
5793         strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(parent_dev),
5794                 sizeof(aux->ddc.name));
5795
5796         return i2c_add_adapter(&aux->ddc);
5797 }
5798
5799 /**
5800  * drm_dp_mst_unregister_i2c_bus() - unregister an I2C-over-AUX adapter
5801  * @port: The port to remove the I2C bus from
5802  */
5803 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port)
5804 {
5805         i2c_del_adapter(&port->aux.ddc);
5806 }
5807
5808 /**
5809  * drm_dp_mst_is_virtual_dpcd() - Is the given port a virtual DP Peer Device
5810  * @port: The port to check
5811  *
5812  * A single physical MST hub object can be represented in the topology
5813  * by multiple branches, with virtual ports between those branches.
5814  *
5815  * As of DP1.4, An MST hub with internal (virtual) ports must expose
5816  * certain DPCD registers over those ports. See sections 2.6.1.1.1
5817  * and 2.6.1.1.2 of Display Port specification v1.4 for details.
5818  *
5819  * May acquire mgr->lock
5820  *
5821  * Returns:
5822  * true if the port is a virtual DP peer device, false otherwise
5823  */
5824 static bool drm_dp_mst_is_virtual_dpcd(struct drm_dp_mst_port *port)
5825 {
5826         struct drm_dp_mst_port *downstream_port;
5827
5828         if (!port || port->dpcd_rev < DP_DPCD_REV_14)
5829                 return false;
5830
5831         /* Virtual DP Sink (Internal Display Panel) */
5832         if (port->port_num >= 8)
5833                 return true;
5834
5835         /* DP-to-HDMI Protocol Converter */
5836         if (port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV &&
5837             !port->mcs &&
5838             port->ldps)
5839                 return true;
5840
5841         /* DP-to-DP */
5842         mutex_lock(&port->mgr->lock);
5843         if (port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
5844             port->mstb &&
5845             port->mstb->num_ports == 2) {
5846                 list_for_each_entry(downstream_port, &port->mstb->ports, next) {
5847                         if (downstream_port->pdt == DP_PEER_DEVICE_SST_SINK &&
5848                             !downstream_port->input) {
5849                                 mutex_unlock(&port->mgr->lock);
5850                                 return true;
5851                         }
5852                 }
5853         }
5854         mutex_unlock(&port->mgr->lock);
5855
5856         return false;
5857 }
5858
5859 /**
5860  * drm_dp_mst_dsc_aux_for_port() - Find the correct aux for DSC
5861  * @port: The port to check. A leaf of the MST tree with an attached display.
5862  *
5863  * Depending on the situation, DSC may be enabled via the endpoint aux,
5864  * the immediately upstream aux, or the connector's physical aux.
5865  *
5866  * This is both the correct aux to read DSC_CAPABILITY and the
5867  * correct aux to write DSC_ENABLED.
5868  *
5869  * This operation can be expensive (up to four aux reads), so
5870  * the caller should cache the return.
5871  *
5872  * Returns:
5873  * NULL if DSC cannot be enabled on this port, otherwise the aux device
5874  */
5875 struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port)
5876 {
5877         struct drm_dp_mst_port *immediate_upstream_port;
5878         struct drm_dp_mst_port *fec_port;
5879         struct drm_dp_desc desc = {};
5880         u8 endpoint_fec;
5881         u8 endpoint_dsc;
5882
5883         if (!port)
5884                 return NULL;
5885
5886         if (port->parent->port_parent)
5887                 immediate_upstream_port = port->parent->port_parent;
5888         else
5889                 immediate_upstream_port = NULL;
5890
5891         fec_port = immediate_upstream_port;
5892         while (fec_port) {
5893                 /*
5894                  * Each physical link (i.e. not a virtual port) between the
5895                  * output and the primary device must support FEC
5896                  */
5897                 if (!drm_dp_mst_is_virtual_dpcd(fec_port) &&
5898                     !fec_port->fec_capable)
5899                         return NULL;
5900
5901                 fec_port = fec_port->parent->port_parent;
5902         }
5903
5904         /* DP-to-DP peer device */
5905         if (drm_dp_mst_is_virtual_dpcd(immediate_upstream_port)) {
5906                 u8 upstream_dsc;
5907
5908                 if (drm_dp_dpcd_read(&port->aux,
5909                                      DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
5910                         return NULL;
5911                 if (drm_dp_dpcd_read(&port->aux,
5912                                      DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
5913                         return NULL;
5914                 if (drm_dp_dpcd_read(&immediate_upstream_port->aux,
5915                                      DP_DSC_SUPPORT, &upstream_dsc, 1) != 1)
5916                         return NULL;
5917
5918                 /* Enpoint decompression with DP-to-DP peer device */
5919                 if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
5920                     (endpoint_fec & DP_FEC_CAPABLE) &&
5921                     (upstream_dsc & 0x2) /* DSC passthrough */)
5922                         return &port->aux;
5923
5924                 /* Virtual DPCD decompression with DP-to-DP peer device */
5925                 return &immediate_upstream_port->aux;
5926         }
5927
5928         /* Virtual DPCD decompression with DP-to-HDMI or Virtual DP Sink */
5929         if (drm_dp_mst_is_virtual_dpcd(port))
5930                 return &port->aux;
5931
5932         /*
5933          * Synaptics quirk
5934          * Applies to ports for which:
5935          * - Physical aux has Synaptics OUI
5936          * - DPv1.4 or higher
5937          * - Port is on primary branch device
5938          * - Not a VGA adapter (DP_DWN_STRM_PORT_TYPE_ANALOG)
5939          */
5940         if (drm_dp_read_desc(port->mgr->aux, &desc, true))
5941                 return NULL;
5942
5943         if (drm_dp_has_quirk(&desc, DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD) &&
5944             port->mgr->dpcd[DP_DPCD_REV] >= DP_DPCD_REV_14 &&
5945             port->parent == port->mgr->mst_primary) {
5946                 u8 dpcd_ext[DP_RECEIVER_CAP_SIZE];
5947
5948                 if (drm_dp_read_dpcd_caps(port->mgr->aux, dpcd_ext) < 0)
5949                         return NULL;
5950
5951                 if ((dpcd_ext[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT) &&
5952                     ((dpcd_ext[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_TYPE_MASK)
5953                      != DP_DWN_STRM_PORT_TYPE_ANALOG))
5954                         return port->mgr->aux;
5955         }
5956
5957         /*
5958          * The check below verifies if the MST sink
5959          * connected to the GPU is capable of DSC -
5960          * therefore the endpoint needs to be
5961          * both DSC and FEC capable.
5962          */
5963         if (drm_dp_dpcd_read(&port->aux,
5964            DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
5965                 return NULL;
5966         if (drm_dp_dpcd_read(&port->aux,
5967            DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
5968                 return NULL;
5969         if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
5970            (endpoint_fec & DP_FEC_CAPABLE))
5971                 return &port->aux;
5972
5973         return NULL;
5974 }
5975 EXPORT_SYMBOL(drm_dp_mst_dsc_aux_for_port);