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