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