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/kernel.h>
  24 #include <linux/delay.h>
  25 #include <linux/init.h>
  26 #include <linux/errno.h>
  27 #include <linux/sched.h>
  28 #include <linux/seq_file.h>
  29 #include <linux/i2c.h>
  30 #include <drm/drm_dp_mst_helper.h>
  31 #include <drm/drmP.h>
  32
  33 #include <drm/drm_fixed.h>
  34
  35 /**
  36  * DOC: dp mst helper
  37  *
  38  * These functions contain parts of the DisplayPort 1.2a MultiStream Transport
  39  * protocol. The helpers contain a topology manager and bandwidth manager.
  40  * The helpers encapsulate the sending and received of sideband msgs.
  41  */
  42 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
  43                                   char *buf);
  44 static int test_calc_pbn_mode(void);
  45
  46 static void drm_dp_put_port(struct drm_dp_mst_port *port);
  47
  48 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
  49                                      int id,
  50                                      struct drm_dp_payload *payload);
  51
  52 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
  53                                   struct drm_dp_mst_port *port,
  54                                   int offset, int size, u8 *bytes);
  55
  56 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
  57                                     struct drm_dp_mst_branch *mstb);
  58 static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
  59                                            struct drm_dp_mst_branch *mstb,
  60                                            struct drm_dp_mst_port *port);
  61 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
  62                                  u8 *guid);
  63
  64 static int drm_dp_mst_register_i2c_bus(struct drm_dp_aux *aux);
  65 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_aux *aux);
  66 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
  67 /* sideband msg handling */
  68 static u8 drm_dp_msg_header_crc4(const uint8_t *data, size_t num_nibbles)
  69 {
  70         u8 bitmask = 0x80;
  71         u8 bitshift = 7;
  72         u8 array_index = 0;
  73         int number_of_bits = num_nibbles * 4;
  74         u8 remainder = 0;
  75
  76         while (number_of_bits != 0) {
  77                 number_of_bits--;
  78                 remainder <<= 1;
  79                 remainder |= (data[array_index] & bitmask) >> bitshift;
  80                 bitmask >>= 1;
  81                 bitshift--;
  82                 if (bitmask == 0) {
  83                         bitmask = 0x80;
  84                         bitshift = 7;
  85                         array_index++;
  86                 }
  87                 if ((remainder & 0x10) == 0x10)
  88                         remainder ^= 0x13;
  89         }
  90
  91         number_of_bits = 4;
  92         while (number_of_bits != 0) {
  93                 number_of_bits--;
  94                 remainder <<= 1;
  95                 if ((remainder & 0x10) != 0)
  96                         remainder ^= 0x13;
  97         }
  98
  99         return remainder;
 100 }
 101
 102 static u8 drm_dp_msg_data_crc4(const uint8_t *data, u8 number_of_bytes)
 103 {
 104         u8 bitmask = 0x80;
 105         u8 bitshift = 7;
 106         u8 array_index = 0;
 107         int number_of_bits = number_of_bytes * 8;
 108         u16 remainder = 0;
 109
 110         while (number_of_bits != 0) {
 111                 number_of_bits--;
 112                 remainder <<= 1;
 113                 remainder |= (data[array_index] & bitmask) >> bitshift;
 114                 bitmask >>= 1;
 115                 bitshift--;
 116                 if (bitmask == 0) {
 117                         bitmask = 0x80;
 118                         bitshift = 7;
 119                         array_index++;
 120                 }
 121                 if ((remainder & 0x100) == 0x100)
 122                         remainder ^= 0xd5;
 123         }
 124
 125         number_of_bits = 8;
 126         while (number_of_bits != 0) {
 127                 number_of_bits--;
 128                 remainder <<= 1;
 129                 if ((remainder & 0x100) != 0)
 130                         remainder ^= 0xd5;
 131         }
 132
 133         return remainder & 0xff;
 134 }
 135 static inline u8 drm_dp_calc_sb_hdr_size(struct drm_dp_sideband_msg_hdr *hdr)
 136 {
 137         u8 size = 3;
 138         size += (hdr->lct / 2);
 139         return size;
 140 }
 141
 142 static void drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
 143                                            u8 *buf, int *len)
 144 {
 145         int idx = 0;
 146         int i;
 147         u8 crc4;
 148         buf[idx++] = ((hdr->lct & 0xf) << 4) | (hdr->lcr & 0xf);
 149         for (i = 0; i < (hdr->lct / 2); i++)
 150                 buf[idx++] = hdr->rad[i];
 151         buf[idx++] = (hdr->broadcast << 7) | (hdr->path_msg << 6) |
 152                 (hdr->msg_len & 0x3f);
 153         buf[idx++] = (hdr->somt << 7) | (hdr->eomt << 6) | (hdr->seqno << 4);
 154
 155         crc4 = drm_dp_msg_header_crc4(buf, (idx * 2) - 1);
 156         buf[idx - 1] |= (crc4 & 0xf);
 157
 158         *len = idx;
 159 }
 160
 161 static bool drm_dp_decode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
 162                                            u8 *buf, int buflen, u8 *hdrlen)
 163 {
 164         u8 crc4;
 165         u8 len;
 166         int i;
 167         u8 idx;
 168         if (buf[0] == 0)
 169                 return false;
 170         len = 3;
 171         len += ((buf[0] & 0xf0) >> 4) / 2;
 172         if (len > buflen)
 173                 return false;
 174         crc4 = drm_dp_msg_header_crc4(buf, (len * 2) - 1);
 175
 176         if ((crc4 & 0xf) != (buf[len - 1] & 0xf)) {
 177                 DRM_DEBUG_KMS("crc4 mismatch 0x%x 0x%x\n", crc4, buf[len - 1]);
 178                 return false;
 179         }
 180
 181         hdr->lct = (buf[0] & 0xf0) >> 4;
 182         hdr->lcr = (buf[0] & 0xf);
 183         idx = 1;
 184         for (i = 0; i < (hdr->lct / 2); i++)
 185                 hdr->rad[i] = buf[idx++];
 186         hdr->broadcast = (buf[idx] >> 7) & 0x1;
 187         hdr->path_msg = (buf[idx] >> 6) & 0x1;
 188         hdr->msg_len = buf[idx] & 0x3f;
 189         idx++;
 190         hdr->somt = (buf[idx] >> 7) & 0x1;
 191         hdr->eomt = (buf[idx] >> 6) & 0x1;
 192         hdr->seqno = (buf[idx] >> 4) & 0x1;
 193         idx++;
 194         *hdrlen = idx;
 195         return true;
 196 }
 197
 198 static void drm_dp_encode_sideband_req(struct drm_dp_sideband_msg_req_body *req,
 199                                        struct drm_dp_sideband_msg_tx *raw)
 200 {
 201         int idx = 0;
 202         int i;
 203         u8 *buf = raw->msg;
 204         buf[idx++] = req->req_type & 0x7f;
 205
 206         switch (req->req_type) {
 207         case DP_ENUM_PATH_RESOURCES:
 208                 buf[idx] = (req->u.port_num.port_number & 0xf) << 4;
 209                 idx++;
 210                 break;
 211         case DP_ALLOCATE_PAYLOAD:
 212                 buf[idx] = (req->u.allocate_payload.port_number & 0xf) << 4 |
 213                         (req->u.allocate_payload.number_sdp_streams & 0xf);
 214                 idx++;
 215                 buf[idx] = (req->u.allocate_payload.vcpi & 0x7f);
 216                 idx++;
 217                 buf[idx] = (req->u.allocate_payload.pbn >> 8);
 218                 idx++;
 219                 buf[idx] = (req->u.allocate_payload.pbn & 0xff);
 220                 idx++;
 221                 for (i = 0; i < req->u.allocate_payload.number_sdp_streams / 2; i++) {
 222                         buf[idx] = ((req->u.allocate_payload.sdp_stream_sink[i * 2] & 0xf) << 4) |
 223                                 (req->u.allocate_payload.sdp_stream_sink[i * 2 + 1] & 0xf);
 224                         idx++;
 225                 }
 226                 if (req->u.allocate_payload.number_sdp_streams & 1) {
 227                         i = req->u.allocate_payload.number_sdp_streams - 1;
 228                         buf[idx] = (req->u.allocate_payload.sdp_stream_sink[i] & 0xf) << 4;
 229                         idx++;
 230                 }
 231                 break;
 232         case DP_QUERY_PAYLOAD:
 233                 buf[idx] = (req->u.query_payload.port_number & 0xf) << 4;
 234                 idx++;
 235                 buf[idx] = (req->u.query_payload.vcpi & 0x7f);
 236                 idx++;
 237                 break;
 238         case DP_REMOTE_DPCD_READ:
 239                 buf[idx] = (req->u.dpcd_read.port_number & 0xf) << 4;
 240                 buf[idx] |= ((req->u.dpcd_read.dpcd_address & 0xf0000) >> 16) & 0xf;
 241                 idx++;
 242                 buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff00) >> 8;
 243                 idx++;
 244                 buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff);
 245                 idx++;
 246                 buf[idx] = (req->u.dpcd_read.num_bytes);
 247                 idx++;
 248                 break;
 249
 250         case DP_REMOTE_DPCD_WRITE:
 251                 buf[idx] = (req->u.dpcd_write.port_number & 0xf) << 4;
 252                 buf[idx] |= ((req->u.dpcd_write.dpcd_address & 0xf0000) >> 16) & 0xf;
 253                 idx++;
 254                 buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff00) >> 8;
 255                 idx++;
 256                 buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff);
 257                 idx++;
 258                 buf[idx] = (req->u.dpcd_write.num_bytes);
 259                 idx++;
 260                 memcpy(&buf[idx], req->u.dpcd_write.bytes, req->u.dpcd_write.num_bytes);
 261                 idx += req->u.dpcd_write.num_bytes;
 262                 break;
 263         case DP_REMOTE_I2C_READ:
 264                 buf[idx] = (req->u.i2c_read.port_number & 0xf) << 4;
 265                 buf[idx] |= (req->u.i2c_read.num_transactions & 0x3);
 266                 idx++;
 267                 for (i = 0; i < (req->u.i2c_read.num_transactions & 0x3); i++) {
 268                         buf[idx] = req->u.i2c_read.transactions[i].i2c_dev_id & 0x7f;
 269                         idx++;
 270                         buf[idx] = req->u.i2c_read.transactions[i].num_bytes;
 271                         idx++;
 272                         memcpy(&buf[idx], req->u.i2c_read.transactions[i].bytes, req->u.i2c_read.transactions[i].num_bytes);
 273                         idx += req->u.i2c_read.transactions[i].num_bytes;
 274
 275                         buf[idx] = (req->u.i2c_read.transactions[i].no_stop_bit & 0x1) << 5;
 276                         buf[idx] |= (req->u.i2c_read.transactions[i].i2c_transaction_delay & 0xf);
 277                         idx++;
 278                 }
 279                 buf[idx] = (req->u.i2c_read.read_i2c_device_id) & 0x7f;
 280                 idx++;
 281                 buf[idx] = (req->u.i2c_read.num_bytes_read);
 282                 idx++;
 283                 break;
 284
 285         case DP_REMOTE_I2C_WRITE:
 286                 buf[idx] = (req->u.i2c_write.port_number & 0xf) << 4;
 287                 idx++;
 288                 buf[idx] = (req->u.i2c_write.write_i2c_device_id) & 0x7f;
 289                 idx++;
 290                 buf[idx] = (req->u.i2c_write.num_bytes);
 291                 idx++;
 292                 memcpy(&buf[idx], req->u.i2c_write.bytes, req->u.i2c_write.num_bytes);
 293                 idx += req->u.i2c_write.num_bytes;
 294                 break;
 295         }
 296         raw->cur_len = idx;
 297 }
 298
 299 static void drm_dp_crc_sideband_chunk_req(u8 *msg, u8 len)
 300 {
 301         u8 crc4;
 302         crc4 = drm_dp_msg_data_crc4(msg, len);
 303         msg[len] = crc4;
 304 }
 305
 306 static void drm_dp_encode_sideband_reply(struct drm_dp_sideband_msg_reply_body *rep,
 307                                          struct drm_dp_sideband_msg_tx *raw)
 308 {
 309         int idx = 0;
 310         u8 *buf = raw->msg;
 311
 312         buf[idx++] = (rep->reply_type & 0x1) << 7 | (rep->req_type & 0x7f);
 313
 314         raw->cur_len = idx;
 315 }
 316
 317 /* this adds a chunk of msg to the builder to get the final msg */
 318 static bool drm_dp_sideband_msg_build(struct drm_dp_sideband_msg_rx *msg,
 319                                       u8 *replybuf, u8 replybuflen, bool hdr)
 320 {
 321         int ret;
 322         u8 crc4;
 323
 324         if (hdr) {
 325                 u8 hdrlen;
 326                 struct drm_dp_sideband_msg_hdr recv_hdr;
 327                 ret = drm_dp_decode_sideband_msg_hdr(&recv_hdr, replybuf, replybuflen, &hdrlen);
 328                 if (ret == false) {
 329                         print_hex_dump(KERN_DEBUG, "failed hdr", DUMP_PREFIX_NONE, 16, 1, replybuf, replybuflen, false);
 330                         return false;
 331                 }
 332
 333                 /* get length contained in this portion */
 334                 msg->curchunk_len = recv_hdr.msg_len;
 335                 msg->curchunk_hdrlen = hdrlen;
 336
 337                 /* we have already gotten an somt - don't bother parsing */
 338                 if (recv_hdr.somt && msg->have_somt)
 339                         return false;
 340
 341                 if (recv_hdr.somt) {
 342                         memcpy(&msg->initial_hdr, &recv_hdr, sizeof(struct drm_dp_sideband_msg_hdr));
 343                         msg->have_somt = true;
 344                 }
 345                 if (recv_hdr.eomt)
 346                         msg->have_eomt = true;
 347
 348                 /* copy the bytes for the remainder of this header chunk */
 349                 msg->curchunk_idx = min(msg->curchunk_len, (u8)(replybuflen - hdrlen));
 350                 memcpy(&msg->chunk[0], replybuf + hdrlen, msg->curchunk_idx);
 351         } else {
 352                 memcpy(&msg->chunk[msg->curchunk_idx], replybuf, replybuflen);
 353                 msg->curchunk_idx += replybuflen;
 354         }
 355
 356         if (msg->curchunk_idx >= msg->curchunk_len) {
 357                 /* do CRC */
 358                 crc4 = drm_dp_msg_data_crc4(msg->chunk, msg->curchunk_len - 1);
 359                 /* copy chunk into bigger msg */
 360                 memcpy(&msg->msg[msg->curlen], msg->chunk, msg->curchunk_len - 1);
 361                 msg->curlen += msg->curchunk_len - 1;
 362         }
 363         return true;
 364 }
 365
 366 static bool drm_dp_sideband_parse_link_address(struct drm_dp_sideband_msg_rx *raw,
 367                                                struct drm_dp_sideband_msg_reply_body *repmsg)
 368 {
 369         int idx = 1;
 370         int i;
 371         memcpy(repmsg->u.link_addr.guid, &raw->msg[idx], 16);
 372         idx += 16;
 373         repmsg->u.link_addr.nports = raw->msg[idx] & 0xf;
 374         idx++;
 375         if (idx > raw->curlen)
 376                 goto fail_len;
 377         for (i = 0; i < repmsg->u.link_addr.nports; i++) {
 378                 if (raw->msg[idx] & 0x80)
 379                         repmsg->u.link_addr.ports[i].input_port = 1;
 380
 381                 repmsg->u.link_addr.ports[i].peer_device_type = (raw->msg[idx] >> 4) & 0x7;
 382                 repmsg->u.link_addr.ports[i].port_number = (raw->msg[idx] & 0xf);
 383
 384                 idx++;
 385                 if (idx > raw->curlen)
 386                         goto fail_len;
 387                 repmsg->u.link_addr.ports[i].mcs = (raw->msg[idx] >> 7) & 0x1;
 388                 repmsg->u.link_addr.ports[i].ddps = (raw->msg[idx] >> 6) & 0x1;
 389                 if (repmsg->u.link_addr.ports[i].input_port == 0)
 390                         repmsg->u.link_addr.ports[i].legacy_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
 391                 idx++;
 392                 if (idx > raw->curlen)
 393                         goto fail_len;
 394                 if (repmsg->u.link_addr.ports[i].input_port == 0) {
 395                         repmsg->u.link_addr.ports[i].dpcd_revision = (raw->msg[idx]);
 396                         idx++;
 397                         if (idx > raw->curlen)
 398                                 goto fail_len;
 399                         memcpy(repmsg->u.link_addr.ports[i].peer_guid, &raw->msg[idx], 16);
 400                         idx += 16;
 401                         if (idx > raw->curlen)
 402                                 goto fail_len;
 403                         repmsg->u.link_addr.ports[i].num_sdp_streams = (raw->msg[idx] >> 4) & 0xf;
 404                         repmsg->u.link_addr.ports[i].num_sdp_stream_sinks = (raw->msg[idx] & 0xf);
 405                         idx++;
 406
 407                 }
 408                 if (idx > raw->curlen)
 409                         goto fail_len;
 410         }
 411
 412         return true;
 413 fail_len:
 414         DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
 415         return false;
 416 }
 417
 418 static bool drm_dp_sideband_parse_remote_dpcd_read(struct drm_dp_sideband_msg_rx *raw,
 419                                                    struct drm_dp_sideband_msg_reply_body *repmsg)
 420 {
 421         int idx = 1;
 422         repmsg->u.remote_dpcd_read_ack.port_number = raw->msg[idx] & 0xf;
 423         idx++;
 424         if (idx > raw->curlen)
 425                 goto fail_len;
 426         repmsg->u.remote_dpcd_read_ack.num_bytes = raw->msg[idx];
 427         if (idx > raw->curlen)
 428                 goto fail_len;
 429
 430         memcpy(repmsg->u.remote_dpcd_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_dpcd_read_ack.num_bytes);
 431         return true;
 432 fail_len:
 433         DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
 434         return false;
 435 }
 436
 437 static bool drm_dp_sideband_parse_remote_dpcd_write(struct drm_dp_sideband_msg_rx *raw,
 438                                                       struct drm_dp_sideband_msg_reply_body *repmsg)
 439 {
 440         int idx = 1;
 441         repmsg->u.remote_dpcd_write_ack.port_number = raw->msg[idx] & 0xf;
 442         idx++;
 443         if (idx > raw->curlen)
 444                 goto fail_len;
 445         return true;
 446 fail_len:
 447         DRM_DEBUG_KMS("parse length fail %d %d\n", idx, raw->curlen);
 448         return false;
 449 }
 450
 451 static bool drm_dp_sideband_parse_remote_i2c_read_ack(struct drm_dp_sideband_msg_rx *raw,
 452                                                       struct drm_dp_sideband_msg_reply_body *repmsg)
 453 {
 454         int idx = 1;
 455
 456         repmsg->u.remote_i2c_read_ack.port_number = (raw->msg[idx] & 0xf);
 457         idx++;
 458         if (idx > raw->curlen)
 459                 goto fail_len;
 460         repmsg->u.remote_i2c_read_ack.num_bytes = raw->msg[idx];
 461         idx++;
 462         /* TODO check */
 463         memcpy(repmsg->u.remote_i2c_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_i2c_read_ack.num_bytes);
 464         return true;
 465 fail_len:
 466         DRM_DEBUG_KMS("remote i2c reply parse length fail %d %d\n", idx, raw->curlen);
 467         return false;
 468 }
 469
 470 static bool drm_dp_sideband_parse_enum_path_resources_ack(struct drm_dp_sideband_msg_rx *raw,
 471                                                           struct drm_dp_sideband_msg_reply_body *repmsg)
 472 {
 473         int idx = 1;
 474         repmsg->u.path_resources.port_number = (raw->msg[idx] >> 4) & 0xf;
 475         idx++;
 476         if (idx > raw->curlen)
 477                 goto fail_len;
 478         repmsg->u.path_resources.full_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 479         idx += 2;
 480         if (idx > raw->curlen)
 481                 goto fail_len;
 482         repmsg->u.path_resources.avail_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 483         idx += 2;
 484         if (idx > raw->curlen)
 485                 goto fail_len;
 486         return true;
 487 fail_len:
 488         DRM_DEBUG_KMS("enum resource parse length fail %d %d\n", idx, raw->curlen);
 489         return false;
 490 }
 491
 492 static bool drm_dp_sideband_parse_allocate_payload_ack(struct drm_dp_sideband_msg_rx *raw,
 493                                                           struct drm_dp_sideband_msg_reply_body *repmsg)
 494 {
 495         int idx = 1;
 496         repmsg->u.allocate_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
 497         idx++;
 498         if (idx > raw->curlen)
 499                 goto fail_len;
 500         repmsg->u.allocate_payload.vcpi = raw->msg[idx];
 501         idx++;
 502         if (idx > raw->curlen)
 503                 goto fail_len;
 504         repmsg->u.allocate_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 505         idx += 2;
 506         if (idx > raw->curlen)
 507                 goto fail_len;
 508         return true;
 509 fail_len:
 510         DRM_DEBUG_KMS("allocate payload parse length fail %d %d\n", idx, raw->curlen);
 511         return false;
 512 }
 513
 514 static bool drm_dp_sideband_parse_query_payload_ack(struct drm_dp_sideband_msg_rx *raw,
 515                                                     struct drm_dp_sideband_msg_reply_body *repmsg)
 516 {
 517         int idx = 1;
 518         repmsg->u.query_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
 519         idx++;
 520         if (idx > raw->curlen)
 521                 goto fail_len;
 522         repmsg->u.query_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
 523         idx += 2;
 524         if (idx > raw->curlen)
 525                 goto fail_len;
 526         return true;
 527 fail_len:
 528         DRM_DEBUG_KMS("query payload parse length fail %d %d\n", idx, raw->curlen);
 529         return false;
 530 }
 531
 532 static bool drm_dp_sideband_parse_reply(struct drm_dp_sideband_msg_rx *raw,
 533                                         struct drm_dp_sideband_msg_reply_body *msg)
 534 {
 535         memset(msg, 0, sizeof(*msg));
 536         msg->reply_type = (raw->msg[0] & 0x80) >> 7;
 537         msg->req_type = (raw->msg[0] & 0x7f);
 538
 539         if (msg->reply_type) {
 540                 memcpy(msg->u.nak.guid, &raw->msg[1], 16);
 541                 msg->u.nak.reason = raw->msg[17];
 542                 msg->u.nak.nak_data = raw->msg[18];
 543                 return false;
 544         }
 545
 546         switch (msg->req_type) {
 547         case DP_LINK_ADDRESS:
 548                 return drm_dp_sideband_parse_link_address(raw, msg);
 549         case DP_QUERY_PAYLOAD:
 550                 return drm_dp_sideband_parse_query_payload_ack(raw, msg);
 551         case DP_REMOTE_DPCD_READ:
 552                 return drm_dp_sideband_parse_remote_dpcd_read(raw, msg);
 553         case DP_REMOTE_DPCD_WRITE:
 554                 return drm_dp_sideband_parse_remote_dpcd_write(raw, msg);
 555         case DP_REMOTE_I2C_READ:
 556                 return drm_dp_sideband_parse_remote_i2c_read_ack(raw, msg);
 557         case DP_ENUM_PATH_RESOURCES:
 558                 return drm_dp_sideband_parse_enum_path_resources_ack(raw, msg);
 559         case DP_ALLOCATE_PAYLOAD:
 560                 return drm_dp_sideband_parse_allocate_payload_ack(raw, msg);
 561         default:
 562                 DRM_ERROR("Got unknown reply 0x%02x\n", msg->req_type);
 563                 return false;
 564         }
 565 }
 566
 567 static bool drm_dp_sideband_parse_connection_status_notify(struct drm_dp_sideband_msg_rx *raw,
 568                                                            struct drm_dp_sideband_msg_req_body *msg)
 569 {
 570         int idx = 1;
 571
 572         msg->u.conn_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
 573         idx++;
 574         if (idx > raw->curlen)
 575                 goto fail_len;
 576
 577         memcpy(msg->u.conn_stat.guid, &raw->msg[idx], 16);
 578         idx += 16;
 579         if (idx > raw->curlen)
 580                 goto fail_len;
 581
 582         msg->u.conn_stat.legacy_device_plug_status = (raw->msg[idx] >> 6) & 0x1;
 583         msg->u.conn_stat.displayport_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
 584         msg->u.conn_stat.message_capability_status = (raw->msg[idx] >> 4) & 0x1;
 585         msg->u.conn_stat.input_port = (raw->msg[idx] >> 3) & 0x1;
 586         msg->u.conn_stat.peer_device_type = (raw->msg[idx] & 0x7);
 587         idx++;
 588         return true;
 589 fail_len:
 590         DRM_DEBUG_KMS("connection status reply parse length fail %d %d\n", idx, raw->curlen);
 591         return false;
 592 }
 593
 594 static bool drm_dp_sideband_parse_resource_status_notify(struct drm_dp_sideband_msg_rx *raw,
 595                                                            struct drm_dp_sideband_msg_req_body *msg)
 596 {
 597         int idx = 1;
 598
 599         msg->u.resource_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
 600         idx++;
 601         if (idx > raw->curlen)
 602                 goto fail_len;
 603
 604         memcpy(msg->u.resource_stat.guid, &raw->msg[idx], 16);
 605         idx += 16;
 606         if (idx > raw->curlen)
 607                 goto fail_len;
 608
 609         msg->u.resource_stat.available_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
 610         idx++;
 611         return true;
 612 fail_len:
 613         DRM_DEBUG_KMS("resource status reply parse length fail %d %d\n", idx, raw->curlen);
 614         return false;
 615 }
 616
 617 static bool drm_dp_sideband_parse_req(struct drm_dp_sideband_msg_rx *raw,
 618                                       struct drm_dp_sideband_msg_req_body *msg)
 619 {
 620         memset(msg, 0, sizeof(*msg));
 621         msg->req_type = (raw->msg[0] & 0x7f);
 622
 623         switch (msg->req_type) {
 624         case DP_CONNECTION_STATUS_NOTIFY:
 625                 return drm_dp_sideband_parse_connection_status_notify(raw, msg);
 626         case DP_RESOURCE_STATUS_NOTIFY:
 627                 return drm_dp_sideband_parse_resource_status_notify(raw, msg);
 628         default:
 629                 DRM_ERROR("Got unknown request 0x%02x\n", msg->req_type);
 630                 return false;
 631         }
 632 }
 633
 634 static int build_dpcd_write(struct drm_dp_sideband_msg_tx *msg, u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
 635 {
 636         struct drm_dp_sideband_msg_req_body req;
 637
 638         req.req_type = DP_REMOTE_DPCD_WRITE;
 639         req.u.dpcd_write.port_number = port_num;
 640         req.u.dpcd_write.dpcd_address = offset;
 641         req.u.dpcd_write.num_bytes = num_bytes;
 642         req.u.dpcd_write.bytes = bytes;
 643         drm_dp_encode_sideband_req(&req, msg);
 644
 645         return 0;
 646 }
 647
 648 static int build_link_address(struct drm_dp_sideband_msg_tx *msg)
 649 {
 650         struct drm_dp_sideband_msg_req_body req;
 651
 652         req.req_type = DP_LINK_ADDRESS;
 653         drm_dp_encode_sideband_req(&req, msg);
 654         return 0;
 655 }
 656
 657 static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg, int port_num)
 658 {
 659         struct drm_dp_sideband_msg_req_body req;
 660
 661         req.req_type = DP_ENUM_PATH_RESOURCES;
 662         req.u.port_num.port_number = port_num;
 663         drm_dp_encode_sideband_req(&req, msg);
 664         msg->path_msg = true;
 665         return 0;
 666 }
 667
 668 static int build_allocate_payload(struct drm_dp_sideband_msg_tx *msg, int port_num,
 669                                   u8 vcpi, uint16_t pbn)
 670 {
 671         struct drm_dp_sideband_msg_req_body req;
 672         memset(&req, 0, sizeof(req));
 673         req.req_type = DP_ALLOCATE_PAYLOAD;
 674         req.u.allocate_payload.port_number = port_num;
 675         req.u.allocate_payload.vcpi = vcpi;
 676         req.u.allocate_payload.pbn = pbn;
 677         drm_dp_encode_sideband_req(&req, msg);
 678         msg->path_msg = true;
 679         return 0;
 680 }
 681
 682 static int drm_dp_mst_assign_payload_id(struct drm_dp_mst_topology_mgr *mgr,
 683                                         struct drm_dp_vcpi *vcpi)
 684 {
 685         int ret, vcpi_ret;
 686
 687         mutex_lock(&mgr->payload_lock);
 688         ret = find_first_zero_bit(&mgr->payload_mask, mgr->max_payloads + 1);
 689         if (ret > mgr->max_payloads) {
 690                 ret = -EINVAL;
 691                 DRM_DEBUG_KMS("out of payload ids %d\n", ret);
 692                 goto out_unlock;
 693         }
 694
 695         vcpi_ret = find_first_zero_bit(&mgr->vcpi_mask, mgr->max_payloads + 1);
 696         if (vcpi_ret > mgr->max_payloads) {
 697                 ret = -EINVAL;
 698                 DRM_DEBUG_KMS("out of vcpi ids %d\n", ret);
 699                 goto out_unlock;
 700         }
 701
 702         set_bit(ret, &mgr->payload_mask);
 703         set_bit(vcpi_ret, &mgr->vcpi_mask);
 704         vcpi->vcpi = vcpi_ret + 1;
 705         mgr->proposed_vcpis[ret - 1] = vcpi;
 706 out_unlock:
 707         mutex_unlock(&mgr->payload_lock);
 708         return ret;
 709 }
 710
 711 static void drm_dp_mst_put_payload_id(struct drm_dp_mst_topology_mgr *mgr,
 712                                       int vcpi)
 713 {
 714         int i;
 715         if (vcpi == 0)
 716                 return;
 717
 718         mutex_lock(&mgr->payload_lock);
 719         DRM_DEBUG_KMS("putting payload %d\n", vcpi);
 720         clear_bit(vcpi - 1, &mgr->vcpi_mask);
 721
 722         for (i = 0; i < mgr->max_payloads; i++) {
 723                 if (mgr->proposed_vcpis[i])
 724                         if (mgr->proposed_vcpis[i]->vcpi == vcpi) {
 725                                 mgr->proposed_vcpis[i] = NULL;
 726                                 clear_bit(i + 1, &mgr->payload_mask);
 727                         }
 728         }
 729         mutex_unlock(&mgr->payload_lock);
 730 }
 731
 732 static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr,
 733                               struct drm_dp_sideband_msg_tx *txmsg)
 734 {
 735         bool ret;
 736
 737         /*
 738          * All updates to txmsg->state are protected by mgr->qlock, and the two
 739          * cases we check here are terminal states. For those the barriers
 740          * provided by the wake_up/wait_event pair are enough.
 741          */
 742         ret = (txmsg->state == DRM_DP_SIDEBAND_TX_RX ||
 743                txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT);
 744         return ret;
 745 }
 746
 747 static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb,
 748                                     struct drm_dp_sideband_msg_tx *txmsg)
 749 {
 750         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
 751         int ret;
 752
 753         ret = wait_event_timeout(mgr->tx_waitq,
 754                                  check_txmsg_state(mgr, txmsg),
 755                                  (4 * HZ));
 756         mutex_lock(&mstb->mgr->qlock);
 757         if (ret > 0) {
 758                 if (txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT) {
 759                         ret = -EIO;
 760                         goto out;
 761                 }
 762         } else {
 763                 DRM_DEBUG_KMS("timedout msg send %p %d %d\n", txmsg, txmsg->state, txmsg->seqno);
 764
 765                 /* dump some state */
 766                 ret = -EIO;
 767
 768                 /* remove from q */
 769                 if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED ||
 770                     txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND) {
 771                         list_del(&txmsg->next);
 772                 }
 773
 774                 if (txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND ||
 775                     txmsg->state == DRM_DP_SIDEBAND_TX_SENT) {
 776                         mstb->tx_slots[txmsg->seqno] = NULL;
 777                 }
 778         }
 779 out:
 780         mutex_unlock(&mgr->qlock);
 781
 782         return ret;
 783 }
 784
 785 static struct drm_dp_mst_branch *drm_dp_add_mst_branch_device(u8 lct, u8 *rad)
 786 {
 787         struct drm_dp_mst_branch *mstb;
 788
 789         mstb = kzalloc(sizeof(*mstb), GFP_KERNEL);
 790         if (!mstb)
 791                 return NULL;
 792
 793         mstb->lct = lct;
 794         if (lct > 1)
 795                 memcpy(mstb->rad, rad, lct / 2);
 796         INIT_LIST_HEAD(&mstb->ports);
 797         kref_init(&mstb->kref);
 798         return mstb;
 799 }
 800
 801 static void drm_dp_destroy_mst_branch_device(struct kref *kref)
 802 {
 803         struct drm_dp_mst_branch *mstb = container_of(kref, struct drm_dp_mst_branch, kref);
 804         struct drm_dp_mst_port *port, *tmp;
 805         bool wake_tx = false;
 806
 807         cancel_work_sync(&mstb->mgr->work);
 808
 809         /*
 810          * destroy all ports - don't need lock
 811          * as there are no more references to the mst branch
 812          * device at this point.
 813          */
 814         list_for_each_entry_safe(port, tmp, &mstb->ports, next) {
 815                 list_del(&port->next);
 816                 drm_dp_put_port(port);
 817         }
 818
 819         /* drop any tx slots msg */
 820         mutex_lock(&mstb->mgr->qlock);
 821         if (mstb->tx_slots[0]) {
 822                 mstb->tx_slots[0]->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
 823                 mstb->tx_slots[0] = NULL;
 824                 wake_tx = true;
 825         }
 826         if (mstb->tx_slots[1]) {
 827                 mstb->tx_slots[1]->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
 828                 mstb->tx_slots[1] = NULL;
 829                 wake_tx = true;
 830         }
 831         mutex_unlock(&mstb->mgr->qlock);
 832
 833         if (wake_tx)
 834                 wake_up(&mstb->mgr->tx_waitq);
 835         kfree(mstb);
 836 }
 837
 838 static void drm_dp_put_mst_branch_device(struct drm_dp_mst_branch *mstb)
 839 {
 840         kref_put(&mstb->kref, drm_dp_destroy_mst_branch_device);
 841 }
 842
 843
 844 static void drm_dp_port_teardown_pdt(struct drm_dp_mst_port *port, int old_pdt)
 845 {
 846         struct drm_dp_mst_branch *mstb;
 847
 848         switch (old_pdt) {
 849         case DP_PEER_DEVICE_DP_LEGACY_CONV:
 850         case DP_PEER_DEVICE_SST_SINK:
 851                 /* remove i2c over sideband */
 852                 drm_dp_mst_unregister_i2c_bus(&port->aux);
 853                 break;
 854         case DP_PEER_DEVICE_MST_BRANCHING:
 855                 mstb = port->mstb;
 856                 port->mstb = NULL;
 857                 drm_dp_put_mst_branch_device(mstb);
 858                 break;
 859         }
 860 }
 861
 862 static void drm_dp_destroy_port(struct kref *kref)
 863 {
 864         struct drm_dp_mst_port *port = container_of(kref, struct drm_dp_mst_port, kref);
 865         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
 866         if (!port->input) {
 867                 port->vcpi.num_slots = 0;
 868
 869                 kfree(port->cached_edid);
 870
 871                 /* we can't destroy the connector here, as
 872                    we might be holding the mode_config.mutex
 873                    from an EDID retrieval */
 874                 if (port->connector) {
 875                         mutex_lock(&mgr->destroy_connector_lock);
 876                         list_add(&port->next, &mgr->destroy_connector_list);
 877                         mutex_unlock(&mgr->destroy_connector_lock);
 878                         schedule_work(&mgr->destroy_connector_work);
 879                         return;
 880                 }
 881                 drm_dp_port_teardown_pdt(port, port->pdt);
 882
 883                 if (!port->input && port->vcpi.vcpi > 0)
 884                         drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
 885         }
 886         kfree(port);
 887
 888         (*mgr->cbs->hotplug)(mgr);
 889 }
 890
 891 static void drm_dp_put_port(struct drm_dp_mst_port *port)
 892 {
 893         kref_put(&port->kref, drm_dp_destroy_port);
 894 }
 895
 896 static struct drm_dp_mst_branch *drm_dp_mst_get_validated_mstb_ref_locked(struct drm_dp_mst_branch *mstb, struct drm_dp_mst_branch *to_find)
 897 {
 898         struct drm_dp_mst_port *port;
 899         struct drm_dp_mst_branch *rmstb;
 900         if (to_find == mstb) {
 901                 kref_get(&mstb->kref);
 902                 return mstb;
 903         }
 904         list_for_each_entry(port, &mstb->ports, next) {
 905                 if (port->mstb) {
 906                         rmstb = drm_dp_mst_get_validated_mstb_ref_locked(port->mstb, to_find);
 907                         if (rmstb)
 908                                 return rmstb;
 909                 }
 910         }
 911         return NULL;
 912 }
 913
 914 static struct drm_dp_mst_branch *drm_dp_get_validated_mstb_ref(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_branch *mstb)
 915 {
 916         struct drm_dp_mst_branch *rmstb = NULL;
 917         mutex_lock(&mgr->lock);
 918         if (mgr->mst_primary)
 919                 rmstb = drm_dp_mst_get_validated_mstb_ref_locked(mgr->mst_primary, mstb);
 920         mutex_unlock(&mgr->lock);
 921         return rmstb;
 922 }
 923
 924 static struct drm_dp_mst_port *drm_dp_mst_get_port_ref_locked(struct drm_dp_mst_branch *mstb, struct drm_dp_mst_port *to_find)
 925 {
 926         struct drm_dp_mst_port *port, *mport;
 927
 928         list_for_each_entry(port, &mstb->ports, next) {
 929                 if (port == to_find) {
 930                         kref_get(&port->kref);
 931                         return port;
 932                 }
 933                 if (port->mstb) {
 934                         mport = drm_dp_mst_get_port_ref_locked(port->mstb, to_find);
 935                         if (mport)
 936                                 return mport;
 937                 }
 938         }
 939         return NULL;
 940 }
 941
 942 static struct drm_dp_mst_port *drm_dp_get_validated_port_ref(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
 943 {
 944         struct drm_dp_mst_port *rport = NULL;
 945         mutex_lock(&mgr->lock);
 946         if (mgr->mst_primary)
 947                 rport = drm_dp_mst_get_port_ref_locked(mgr->mst_primary, port);
 948         mutex_unlock(&mgr->lock);
 949         return rport;
 950 }
 951
 952 static struct drm_dp_mst_port *drm_dp_get_port(struct drm_dp_mst_branch *mstb, u8 port_num)
 953 {
 954         struct drm_dp_mst_port *port;
 955
 956         list_for_each_entry(port, &mstb->ports, next) {
 957                 if (port->port_num == port_num) {
 958                         kref_get(&port->kref);
 959                         return port;
 960                 }
 961         }
 962
 963         return NULL;
 964 }
 965
 966 /*
 967  * calculate a new RAD for this MST branch device
 968  * if parent has an LCT of 2 then it has 1 nibble of RAD,
 969  * if parent has an LCT of 3 then it has 2 nibbles of RAD,
 970  */
 971 static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port,
 972                                  u8 *rad)
 973 {
 974         int lct = port->parent->lct;
 975         int shift = 4;
 976         int idx = lct / 2;
 977         if (lct > 1) {
 978                 memcpy(rad, port->parent->rad, idx);
 979                 shift = (lct % 2) ? 4 : 0;
 980         } else
 981                 rad[0] = 0;
 982
 983         rad[idx] |= port->port_num << shift;
 984         return lct + 1;
 985 }
 986
 987 /*
 988  * return sends link address for new mstb
 989  */
 990 static bool drm_dp_port_setup_pdt(struct drm_dp_mst_port *port)
 991 {
 992         int ret;
 993         u8 rad[6], lct;
 994         bool send_link = false;
 995         switch (port->pdt) {
 996         case DP_PEER_DEVICE_DP_LEGACY_CONV:
 997         case DP_PEER_DEVICE_SST_SINK:
 998                 /* add i2c over sideband */
 999                 ret = drm_dp_mst_register_i2c_bus(&port->aux);
1000                 break;
1001         case DP_PEER_DEVICE_MST_BRANCHING:
1002                 lct = drm_dp_calculate_rad(port, rad);
1003
1004                 port->mstb = drm_dp_add_mst_branch_device(lct, rad);
1005                 port->mstb->mgr = port->mgr;
1006                 port->mstb->port_parent = port;
1007
1008                 send_link = true;
1009                 break;
1010         }
1011         return send_link;
1012 }
1013
1014 static void drm_dp_check_port_guid(struct drm_dp_mst_branch *mstb,
1015                                    struct drm_dp_mst_port *port)
1016 {
1017         int ret;
1018         if (port->dpcd_rev >= 0x12) {
1019                 port->guid_valid = drm_dp_validate_guid(mstb->mgr, port->guid);
1020                 if (!port->guid_valid) {
1021                         ret = drm_dp_send_dpcd_write(mstb->mgr,
1022                                                      port,
1023                                                      DP_GUID,
1024                                                      16, port->guid);
1025                         port->guid_valid = true;
1026                 }
1027         }
1028 }
1029
1030 static void build_mst_prop_path(struct drm_dp_mst_port *port,
1031                                 struct drm_dp_mst_branch *mstb,
1032                                 char *proppath,
1033                                 size_t proppath_size)
1034 {
1035         int i;
1036         char temp[8];
1037         snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id);
1038         for (i = 0; i < (mstb->lct - 1); i++) {
1039                 int shift = (i % 2) ? 0 : 4;
1040                 int port_num = mstb->rad[i / 2] >> shift;
1041                 snprintf(temp, sizeof(temp), "-%d", port_num);
1042                 strlcat(proppath, temp, proppath_size);
1043         }
1044         snprintf(temp, sizeof(temp), "-%d", port->port_num);
1045         strlcat(proppath, temp, proppath_size);
1046 }
1047
1048 static void drm_dp_add_port(struct drm_dp_mst_branch *mstb,
1049                             struct device *dev,
1050                             struct drm_dp_link_addr_reply_port *port_msg)
1051 {
1052         struct drm_dp_mst_port *port;
1053         bool ret;
1054         bool created = false;
1055         int old_pdt = 0;
1056         int old_ddps = 0;
1057         port = drm_dp_get_port(mstb, port_msg->port_number);
1058         if (!port) {
1059                 port = kzalloc(sizeof(*port), GFP_KERNEL);
1060                 if (!port)
1061                         return;
1062                 kref_init(&port->kref);
1063                 port->parent = mstb;
1064                 port->port_num = port_msg->port_number;
1065                 port->mgr = mstb->mgr;
1066                 port->aux.name = "DPMST";
1067                 port->aux.dev = dev;
1068                 created = true;
1069         } else {
1070                 old_pdt = port->pdt;
1071                 old_ddps = port->ddps;
1072         }
1073
1074         port->pdt = port_msg->peer_device_type;
1075         port->input = port_msg->input_port;
1076         port->mcs = port_msg->mcs;
1077         port->ddps = port_msg->ddps;
1078         port->ldps = port_msg->legacy_device_plug_status;
1079         port->dpcd_rev = port_msg->dpcd_revision;
1080         port->num_sdp_streams = port_msg->num_sdp_streams;
1081         port->num_sdp_stream_sinks = port_msg->num_sdp_stream_sinks;
1082         memcpy(port->guid, port_msg->peer_guid, 16);
1083
1084         /* manage mstb port lists with mgr lock - take a reference
1085            for this list */
1086         if (created) {
1087                 mutex_lock(&mstb->mgr->lock);
1088                 kref_get(&port->kref);
1089                 list_add(&port->next, &mstb->ports);
1090                 mutex_unlock(&mstb->mgr->lock);
1091         }
1092
1093         if (old_ddps != port->ddps) {
1094                 if (port->ddps) {
1095                         drm_dp_check_port_guid(mstb, port);
1096                         if (!port->input)
1097                                 drm_dp_send_enum_path_resources(mstb->mgr, mstb, port);
1098                 } else {
1099                         port->guid_valid = false;
1100                         port->available_pbn = 0;
1101                         }
1102         }
1103
1104         if (old_pdt != port->pdt && !port->input) {
1105                 drm_dp_port_teardown_pdt(port, old_pdt);
1106
1107                 ret = drm_dp_port_setup_pdt(port);
1108                 if (ret == true) {
1109                         drm_dp_send_link_address(mstb->mgr, port->mstb);
1110                         port->mstb->link_address_sent = true;
1111                 }
1112         }
1113
1114         if (created && !port->input) {
1115                 char proppath[255];
1116                 build_mst_prop_path(port, mstb, proppath, sizeof(proppath));
1117                 port->connector = (*mstb->mgr->cbs->add_connector)(mstb->mgr, port, proppath);
1118
1119                 if (port->port_num >= 8) {
1120                         port->cached_edid = drm_get_edid(port->connector, &port->aux.ddc);
1121                 }
1122         }
1123
1124         /* put reference to this port */
1125         drm_dp_put_port(port);
1126 }
1127
1128 static void drm_dp_update_port(struct drm_dp_mst_branch *mstb,
1129                                struct drm_dp_connection_status_notify *conn_stat)
1130 {
1131         struct drm_dp_mst_port *port;
1132         int old_pdt;
1133         int old_ddps;
1134         bool dowork = false;
1135         port = drm_dp_get_port(mstb, conn_stat->port_number);
1136         if (!port)
1137                 return;
1138
1139         old_ddps = port->ddps;
1140         old_pdt = port->pdt;
1141         port->pdt = conn_stat->peer_device_type;
1142         port->mcs = conn_stat->message_capability_status;
1143         port->ldps = conn_stat->legacy_device_plug_status;
1144         port->ddps = conn_stat->displayport_device_plug_status;
1145
1146         if (old_ddps != port->ddps) {
1147                 if (port->ddps) {
1148                         drm_dp_check_port_guid(mstb, port);
1149                         dowork = true;
1150                 } else {
1151                         port->guid_valid = false;
1152                         port->available_pbn = 0;
1153                 }
1154         }
1155         if (old_pdt != port->pdt && !port->input) {
1156                 drm_dp_port_teardown_pdt(port, old_pdt);
1157
1158                 if (drm_dp_port_setup_pdt(port))
1159                         dowork = true;
1160         }
1161
1162         drm_dp_put_port(port);
1163         if (dowork)
1164                 queue_work(system_long_wq, &mstb->mgr->work);
1165
1166 }
1167
1168 static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr *mgr,
1169                                                                u8 lct, u8 *rad)
1170 {
1171         struct drm_dp_mst_branch *mstb;
1172         struct drm_dp_mst_port *port;
1173         int i;
1174         /* find the port by iterating down */
1175
1176         mutex_lock(&mgr->lock);
1177         mstb = mgr->mst_primary;
1178
1179         for (i = 0; i < lct - 1; i++) {
1180                 int shift = (i % 2) ? 0 : 4;
1181                 int port_num = rad[i / 2] >> shift;
1182
1183                 list_for_each_entry(port, &mstb->ports, next) {
1184                         if (port->port_num == port_num) {
1185                                 if (!port->mstb) {
1186                                         DRM_ERROR("failed to lookup MSTB with lct %d, rad %02x\n", lct, rad[0]);
1187                                         return NULL;
1188                                 }
1189
1190                                 mstb = port->mstb;
1191                                 break;
1192                         }
1193                 }
1194         }
1195         kref_get(&mstb->kref);
1196         mutex_unlock(&mgr->lock);
1197         return mstb;
1198 }
1199
1200 static void drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
1201                                                struct drm_dp_mst_branch *mstb)
1202 {
1203         struct drm_dp_mst_port *port;
1204         struct drm_dp_mst_branch *mstb_child;
1205         if (!mstb->link_address_sent) {
1206                 drm_dp_send_link_address(mgr, mstb);
1207                 mstb->link_address_sent = true;
1208         }
1209         list_for_each_entry(port, &mstb->ports, next) {
1210                 if (port->input)
1211                         continue;
1212
1213                 if (!port->ddps)
1214                         continue;
1215
1216                 if (!port->available_pbn)
1217                         drm_dp_send_enum_path_resources(mgr, mstb, port);
1218
1219                 if (port->mstb) {
1220                         mstb_child = drm_dp_get_validated_mstb_ref(mgr, port->mstb);
1221                         if (mstb_child) {
1222                                 drm_dp_check_and_send_link_address(mgr, mstb_child);
1223                                 drm_dp_put_mst_branch_device(mstb_child);
1224                         }
1225                 }
1226         }
1227 }
1228
1229 static void drm_dp_mst_link_probe_work(struct work_struct *work)
1230 {
1231         struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, work);
1232         struct drm_dp_mst_branch *mstb;
1233
1234         mutex_lock(&mgr->lock);
1235         mstb = mgr->mst_primary;
1236         if (mstb) {
1237                 kref_get(&mstb->kref);
1238         }
1239         mutex_unlock(&mgr->lock);
1240         if (mstb) {
1241                 drm_dp_check_and_send_link_address(mgr, mstb);
1242                 drm_dp_put_mst_branch_device(mstb);
1243         }
1244 }
1245
1246 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
1247                                  u8 *guid)
1248 {
1249         static u8 zero_guid[16];
1250
1251         if (!memcmp(guid, zero_guid, 16)) {
1252                 u64 salt = get_jiffies_64();
1253                 memcpy(&guid[0], &salt, sizeof(u64));
1254                 memcpy(&guid[8], &salt, sizeof(u64));
1255                 return false;
1256         }
1257         return true;
1258 }
1259
1260 #if 0
1261 static int build_dpcd_read(struct drm_dp_sideband_msg_tx *msg, u8 port_num, u32 offset, u8 num_bytes)
1262 {
1263         struct drm_dp_sideband_msg_req_body req;
1264
1265         req.req_type = DP_REMOTE_DPCD_READ;
1266         req.u.dpcd_read.port_number = port_num;
1267         req.u.dpcd_read.dpcd_address = offset;
1268         req.u.dpcd_read.num_bytes = num_bytes;
1269         drm_dp_encode_sideband_req(&req, msg);
1270
1271         return 0;
1272 }
1273 #endif
1274
1275 static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr,
1276                                     bool up, u8 *msg, int len)
1277 {
1278         int ret;
1279         int regbase = up ? DP_SIDEBAND_MSG_UP_REP_BASE : DP_SIDEBAND_MSG_DOWN_REQ_BASE;
1280         int tosend, total, offset;
1281         int retries = 0;
1282
1283 retry:
1284         total = len;
1285         offset = 0;
1286         do {
1287                 tosend = min3(mgr->max_dpcd_transaction_bytes, 16, total);
1288
1289                 ret = drm_dp_dpcd_write(mgr->aux, regbase + offset,
1290                                         &msg[offset],
1291                                         tosend);
1292                 if (ret != tosend) {
1293                         if (ret == -EIO && retries < 5) {
1294                                 retries++;
1295                                 goto retry;
1296                         }
1297                         DRM_DEBUG_KMS("failed to dpcd write %d %d\n", tosend, ret);
1298
1299                         return -EIO;
1300                 }
1301                 offset += tosend;
1302                 total -= tosend;
1303         } while (total > 0);
1304         return 0;
1305 }
1306
1307 static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr,
1308                                   struct drm_dp_sideband_msg_tx *txmsg)
1309 {
1310         struct drm_dp_mst_branch *mstb = txmsg->dst;
1311
1312         /* both msg slots are full */
1313         if (txmsg->seqno == -1) {
1314                 if (mstb->tx_slots[0] && mstb->tx_slots[1]) {
1315                         DRM_DEBUG_KMS("%s: failed to find slot\n", __func__);
1316                         return -EAGAIN;
1317                 }
1318                 if (mstb->tx_slots[0] == NULL && mstb->tx_slots[1] == NULL) {
1319                         txmsg->seqno = mstb->last_seqno;
1320                         mstb->last_seqno ^= 1;
1321                 } else if (mstb->tx_slots[0] == NULL)
1322                         txmsg->seqno = 0;
1323                 else
1324                         txmsg->seqno = 1;
1325                 mstb->tx_slots[txmsg->seqno] = txmsg;
1326         }
1327         hdr->broadcast = 0;
1328         hdr->path_msg = txmsg->path_msg;
1329         hdr->lct = mstb->lct;
1330         hdr->lcr = mstb->lct - 1;
1331         if (mstb->lct > 1)
1332                 memcpy(hdr->rad, mstb->rad, mstb->lct / 2);
1333         hdr->seqno = txmsg->seqno;
1334         return 0;
1335 }
1336 /*
1337  * process a single block of the next message in the sideband queue
1338  */
1339 static int process_single_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
1340                                    struct drm_dp_sideband_msg_tx *txmsg,
1341                                    bool up)
1342 {
1343         u8 chunk[48];
1344         struct drm_dp_sideband_msg_hdr hdr;
1345         int len, space, idx, tosend;
1346         int ret;
1347
1348         memset(&hdr, 0, sizeof(struct drm_dp_sideband_msg_hdr));
1349
1350         if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED) {
1351                 txmsg->seqno = -1;
1352                 txmsg->state = DRM_DP_SIDEBAND_TX_START_SEND;
1353         }
1354
1355         /* make hdr from dst mst - for replies use seqno
1356            otherwise assign one */
1357         ret = set_hdr_from_dst_qlock(&hdr, txmsg);
1358         if (ret < 0)
1359                 return ret;
1360
1361         /* amount left to send in this message */
1362         len = txmsg->cur_len - txmsg->cur_offset;
1363
1364         /* 48 - sideband msg size - 1 byte for data CRC, x header bytes */
1365         space = 48 - 1 - drm_dp_calc_sb_hdr_size(&hdr);
1366
1367         tosend = min(len, space);
1368         if (len == txmsg->cur_len)
1369                 hdr.somt = 1;
1370         if (space >= len)
1371                 hdr.eomt = 1;
1372
1373
1374         hdr.msg_len = tosend + 1;
1375         drm_dp_encode_sideband_msg_hdr(&hdr, chunk, &idx);
1376         memcpy(&chunk[idx], &txmsg->msg[txmsg->cur_offset], tosend);
1377         /* add crc at end */
1378         drm_dp_crc_sideband_chunk_req(&chunk[idx], tosend);
1379         idx += tosend + 1;
1380
1381         ret = drm_dp_send_sideband_msg(mgr, up, chunk, idx);
1382         if (ret) {
1383                 DRM_DEBUG_KMS("sideband msg failed to send\n");
1384                 return ret;
1385         }
1386
1387         txmsg->cur_offset += tosend;
1388         if (txmsg->cur_offset == txmsg->cur_len) {
1389                 txmsg->state = DRM_DP_SIDEBAND_TX_SENT;
1390                 return 1;
1391         }
1392         return 0;
1393 }
1394
1395 static void process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr *mgr)
1396 {
1397         struct drm_dp_sideband_msg_tx *txmsg;
1398         int ret;
1399
1400         WARN_ON(!mutex_is_locked(&mgr->qlock));
1401
1402         /* construct a chunk from the first msg in the tx_msg queue */
1403         if (list_empty(&mgr->tx_msg_downq)) {
1404                 mgr->tx_down_in_progress = false;
1405                 return;
1406         }
1407         mgr->tx_down_in_progress = true;
1408
1409         txmsg = list_first_entry(&mgr->tx_msg_downq, struct drm_dp_sideband_msg_tx, next);
1410         ret = process_single_tx_qlock(mgr, txmsg, false);
1411         if (ret == 1) {
1412                 /* txmsg is sent it should be in the slots now */
1413                 list_del(&txmsg->next);
1414         } else if (ret) {
1415                 DRM_DEBUG_KMS("failed to send msg in q %d\n", ret);
1416                 list_del(&txmsg->next);
1417                 if (txmsg->seqno != -1)
1418                         txmsg->dst->tx_slots[txmsg->seqno] = NULL;
1419                 txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
1420                 wake_up(&mgr->tx_waitq);
1421         }
1422         if (list_empty(&mgr->tx_msg_downq)) {
1423                 mgr->tx_down_in_progress = false;
1424                 return;
1425         }
1426 }
1427
1428 /* called holding qlock */
1429 static void process_single_up_tx_qlock(struct drm_dp_mst_topology_mgr *mgr)
1430 {
1431         struct drm_dp_sideband_msg_tx *txmsg;
1432         int ret;
1433
1434         /* construct a chunk from the first msg in the tx_msg queue */
1435         if (list_empty(&mgr->tx_msg_upq)) {
1436                 mgr->tx_up_in_progress = false;
1437                 return;
1438         }
1439
1440         txmsg = list_first_entry(&mgr->tx_msg_upq, struct drm_dp_sideband_msg_tx, next);
1441         ret = process_single_tx_qlock(mgr, txmsg, true);
1442         if (ret == 1) {
1443                 /* up txmsgs aren't put in slots - so free after we send it */
1444                 list_del(&txmsg->next);
1445                 kfree(txmsg);
1446         } else if (ret)
1447                 DRM_DEBUG_KMS("failed to send msg in q %d\n", ret);
1448         mgr->tx_up_in_progress = true;
1449 }
1450
1451 static void drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr *mgr,
1452                                  struct drm_dp_sideband_msg_tx *txmsg)
1453 {
1454         mutex_lock(&mgr->qlock);
1455         list_add_tail(&txmsg->next, &mgr->tx_msg_downq);
1456         if (!mgr->tx_down_in_progress)
1457                 process_single_down_tx_qlock(mgr);
1458         mutex_unlock(&mgr->qlock);
1459 }
1460
1461 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
1462                                     struct drm_dp_mst_branch *mstb)
1463 {
1464         int len;
1465         struct drm_dp_sideband_msg_tx *txmsg;
1466         int ret;
1467
1468         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1469         if (!txmsg)
1470                 return -ENOMEM;
1471
1472         txmsg->dst = mstb;
1473         len = build_link_address(txmsg);
1474
1475         drm_dp_queue_down_tx(mgr, txmsg);
1476
1477         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
1478         if (ret > 0) {
1479                 int i;
1480
1481                 if (txmsg->reply.reply_type == 1)
1482                         DRM_DEBUG_KMS("link address nak received\n");
1483                 else {
1484                         DRM_DEBUG_KMS("link address reply: %d\n", txmsg->reply.u.link_addr.nports);
1485                         for (i = 0; i < txmsg->reply.u.link_addr.nports; i++) {
1486                                 DRM_DEBUG_KMS("port %d: input %d, pdt: %d, pn: %d, dpcd_rev: %02x, mcs: %d, ddps: %d, ldps %d, sdp %d/%d\n", i,
1487                                        txmsg->reply.u.link_addr.ports[i].input_port,
1488                                        txmsg->reply.u.link_addr.ports[i].peer_device_type,
1489                                        txmsg->reply.u.link_addr.ports[i].port_number,
1490                                        txmsg->reply.u.link_addr.ports[i].dpcd_revision,
1491                                        txmsg->reply.u.link_addr.ports[i].mcs,
1492                                        txmsg->reply.u.link_addr.ports[i].ddps,
1493                                        txmsg->reply.u.link_addr.ports[i].legacy_device_plug_status,
1494                                        txmsg->reply.u.link_addr.ports[i].num_sdp_streams,
1495                                        txmsg->reply.u.link_addr.ports[i].num_sdp_stream_sinks);
1496                         }
1497                         for (i = 0; i < txmsg->reply.u.link_addr.nports; i++) {
1498                                 drm_dp_add_port(mstb, mgr->dev, &txmsg->reply.u.link_addr.ports[i]);
1499                         }
1500                         (*mgr->cbs->hotplug)(mgr);
1501                 }
1502         } else
1503                 DRM_DEBUG_KMS("link address failed %d\n", ret);
1504
1505         kfree(txmsg);
1506         return 0;
1507 }
1508
1509 static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
1510                                            struct drm_dp_mst_branch *mstb,
1511                                            struct drm_dp_mst_port *port)
1512 {
1513         int len;
1514         struct drm_dp_sideband_msg_tx *txmsg;
1515         int ret;
1516
1517         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1518         if (!txmsg)
1519                 return -ENOMEM;
1520
1521         txmsg->dst = mstb;
1522         len = build_enum_path_resources(txmsg, port->port_num);
1523
1524         drm_dp_queue_down_tx(mgr, txmsg);
1525
1526         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
1527         if (ret > 0) {
1528                 if (txmsg->reply.reply_type == 1)
1529                         DRM_DEBUG_KMS("enum path resources nak received\n");
1530                 else {
1531                         if (port->port_num != txmsg->reply.u.path_resources.port_number)
1532                                 DRM_ERROR("got incorrect port in response\n");
1533                         DRM_DEBUG_KMS("enum path resources %d: %d %d\n", txmsg->reply.u.path_resources.port_number, txmsg->reply.u.path_resources.full_payload_bw_number,
1534                                txmsg->reply.u.path_resources.avail_payload_bw_number);
1535                         port->available_pbn = txmsg->reply.u.path_resources.avail_payload_bw_number;
1536                 }
1537         }
1538
1539         kfree(txmsg);
1540         return 0;
1541 }
1542
1543 static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
1544                                    struct drm_dp_mst_port *port,
1545                                    int id,
1546                                    int pbn)
1547 {
1548         struct drm_dp_sideband_msg_tx *txmsg;
1549         struct drm_dp_mst_branch *mstb;
1550         int len, ret;
1551
1552         mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
1553         if (!mstb)
1554                 return -EINVAL;
1555
1556         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1557         if (!txmsg) {
1558                 ret = -ENOMEM;
1559                 goto fail_put;
1560         }
1561
1562         txmsg->dst = mstb;
1563         len = build_allocate_payload(txmsg, port->port_num,
1564                                      id,
1565                                      pbn);
1566
1567         drm_dp_queue_down_tx(mgr, txmsg);
1568
1569         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
1570         if (ret > 0) {
1571                 if (txmsg->reply.reply_type == 1) {
1572                         ret = -EINVAL;
1573                 } else
1574                         ret = 0;
1575         }
1576         kfree(txmsg);
1577 fail_put:
1578         drm_dp_put_mst_branch_device(mstb);
1579         return ret;
1580 }
1581
1582 static int drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
1583                                        int id,
1584                                        struct drm_dp_payload *payload)
1585 {
1586         int ret;
1587
1588         ret = drm_dp_dpcd_write_payload(mgr, id, payload);
1589         if (ret < 0) {
1590                 payload->payload_state = 0;
1591                 return ret;
1592         }
1593         payload->payload_state = DP_PAYLOAD_LOCAL;
1594         return 0;
1595 }
1596
1597 static int drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
1598                                        struct drm_dp_mst_port *port,
1599                                        int id,
1600                                        struct drm_dp_payload *payload)
1601 {
1602         int ret;
1603         ret = drm_dp_payload_send_msg(mgr, port, id, port->vcpi.pbn);
1604         if (ret < 0)
1605                 return ret;
1606         payload->payload_state = DP_PAYLOAD_REMOTE;
1607         return ret;
1608 }
1609
1610 static int drm_dp_destroy_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
1611                                         struct drm_dp_mst_port *port,
1612                                         int id,
1613                                         struct drm_dp_payload *payload)
1614 {
1615         DRM_DEBUG_KMS("\n");
1616         /* its okay for these to fail */
1617         if (port) {
1618                 drm_dp_payload_send_msg(mgr, port, id, 0);
1619         }
1620
1621         drm_dp_dpcd_write_payload(mgr, id, payload);
1622         payload->payload_state = DP_PAYLOAD_DELETE_LOCAL;
1623         return 0;
1624 }
1625
1626 static int drm_dp_destroy_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
1627                                         int id,
1628                                         struct drm_dp_payload *payload)
1629 {
1630         payload->payload_state = 0;
1631         return 0;
1632 }
1633
1634 /**
1635  * drm_dp_update_payload_part1() - Execute payload update part 1
1636  * @mgr: manager to use.
1637  *
1638  * This iterates over all proposed virtual channels, and tries to
1639  * allocate space in the link for them. For 0->slots transitions,
1640  * this step just writes the VCPI to the MST device. For slots->0
1641  * transitions, this writes the updated VCPIs and removes the
1642  * remote VC payloads.
1643  *
1644  * after calling this the driver should generate ACT and payload
1645  * packets.
1646  */
1647 int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
1648 {
1649         int i, j;
1650         int cur_slots = 1;
1651         struct drm_dp_payload req_payload;
1652         struct drm_dp_mst_port *port;
1653
1654         mutex_lock(&mgr->payload_lock);
1655         for (i = 0; i < mgr->max_payloads; i++) {
1656                 /* solve the current payloads - compare to the hw ones
1657                    - update the hw view */
1658                 req_payload.start_slot = cur_slots;
1659                 if (mgr->proposed_vcpis[i]) {
1660                         port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
1661                         req_payload.num_slots = mgr->proposed_vcpis[i]->num_slots;
1662                 } else {
1663                         port = NULL;
1664                         req_payload.num_slots = 0;
1665                 }
1666
1667                 if (mgr->payloads[i].start_slot != req_payload.start_slot) {
1668                         mgr->payloads[i].start_slot = req_payload.start_slot;
1669                 }
1670                 /* work out what is required to happen with this payload */
1671                 if (mgr->payloads[i].num_slots != req_payload.num_slots) {
1672
1673                         /* need to push an update for this payload */
1674                         if (req_payload.num_slots) {
1675                                 drm_dp_create_payload_step1(mgr, mgr->proposed_vcpis[i]->vcpi, &req_payload);
1676                                 mgr->payloads[i].num_slots = req_payload.num_slots;
1677                         } else if (mgr->payloads[i].num_slots) {
1678                                 mgr->payloads[i].num_slots = 0;
1679                                 drm_dp_destroy_payload_step1(mgr, port, port->vcpi.vcpi, &mgr->payloads[i]);
1680                                 req_payload.payload_state = mgr->payloads[i].payload_state;
1681                                 mgr->payloads[i].start_slot = 0;
1682                         }
1683                         mgr->payloads[i].payload_state = req_payload.payload_state;
1684                 }
1685                 cur_slots += req_payload.num_slots;
1686         }
1687
1688         for (i = 0; i < mgr->max_payloads; i++) {
1689                 if (mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) {
1690                         DRM_DEBUG_KMS("removing payload %d\n", i);
1691                         for (j = i; j < mgr->max_payloads - 1; j++) {
1692                                 memcpy(&mgr->payloads[j], &mgr->payloads[j + 1], sizeof(struct drm_dp_payload));
1693                                 mgr->proposed_vcpis[j] = mgr->proposed_vcpis[j + 1];
1694                                 if (mgr->proposed_vcpis[j] && mgr->proposed_vcpis[j]->num_slots) {
1695                                         set_bit(j + 1, &mgr->payload_mask);
1696                                 } else {
1697                                         clear_bit(j + 1, &mgr->payload_mask);
1698                                 }
1699                         }
1700                         memset(&mgr->payloads[mgr->max_payloads - 1], 0, sizeof(struct drm_dp_payload));
1701                         mgr->proposed_vcpis[mgr->max_payloads - 1] = NULL;
1702                         clear_bit(mgr->max_payloads, &mgr->payload_mask);
1703
1704                 }
1705         }
1706         mutex_unlock(&mgr->payload_lock);
1707
1708         return 0;
1709 }
1710 EXPORT_SYMBOL(drm_dp_update_payload_part1);
1711
1712 /**
1713  * drm_dp_update_payload_part2() - Execute payload update part 2
1714  * @mgr: manager to use.
1715  *
1716  * This iterates over all proposed virtual channels, and tries to
1717  * allocate space in the link for them. For 0->slots transitions,
1718  * this step writes the remote VC payload commands. For slots->0
1719  * this just resets some internal state.
1720  */
1721 int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
1722 {
1723         struct drm_dp_mst_port *port;
1724         int i;
1725         int ret = 0;
1726         mutex_lock(&mgr->payload_lock);
1727         for (i = 0; i < mgr->max_payloads; i++) {
1728
1729                 if (!mgr->proposed_vcpis[i])
1730                         continue;
1731
1732                 port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
1733
1734                 DRM_DEBUG_KMS("payload %d %d\n", i, mgr->payloads[i].payload_state);
1735                 if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL) {
1736                         ret = drm_dp_create_payload_step2(mgr, port, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
1737                 } else if (mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) {
1738                         ret = drm_dp_destroy_payload_step2(mgr, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
1739                 }
1740                 if (ret) {
1741                         mutex_unlock(&mgr->payload_lock);
1742                         return ret;
1743                 }
1744         }
1745         mutex_unlock(&mgr->payload_lock);
1746         return 0;
1747 }
1748 EXPORT_SYMBOL(drm_dp_update_payload_part2);
1749
1750 #if 0 /* unused as of yet */
1751 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
1752                                  struct drm_dp_mst_port *port,
1753                                  int offset, int size)
1754 {
1755         int len;
1756         struct drm_dp_sideband_msg_tx *txmsg;
1757
1758         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1759         if (!txmsg)
1760                 return -ENOMEM;
1761
1762         len = build_dpcd_read(txmsg, port->port_num, 0, 8);
1763         txmsg->dst = port->parent;
1764
1765         drm_dp_queue_down_tx(mgr, txmsg);
1766
1767         return 0;
1768 }
1769 #endif
1770
1771 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
1772                                   struct drm_dp_mst_port *port,
1773                                   int offset, int size, u8 *bytes)
1774 {
1775         int len;
1776         int ret;
1777         struct drm_dp_sideband_msg_tx *txmsg;
1778         struct drm_dp_mst_branch *mstb;
1779
1780         mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
1781         if (!mstb)
1782                 return -EINVAL;
1783
1784         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1785         if (!txmsg) {
1786                 ret = -ENOMEM;
1787                 goto fail_put;
1788         }
1789
1790         len = build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
1791         txmsg->dst = mstb;
1792
1793         drm_dp_queue_down_tx(mgr, txmsg);
1794
1795         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
1796         if (ret > 0) {
1797                 if (txmsg->reply.reply_type == 1) {
1798                         ret = -EINVAL;
1799                 } else
1800                         ret = 0;
1801         }
1802         kfree(txmsg);
1803 fail_put:
1804         drm_dp_put_mst_branch_device(mstb);
1805         return ret;
1806 }
1807
1808 static int drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx *msg, u8 req_type)
1809 {
1810         struct drm_dp_sideband_msg_reply_body reply;
1811
1812         reply.reply_type = 1;
1813         reply.req_type = req_type;
1814         drm_dp_encode_sideband_reply(&reply, msg);
1815         return 0;
1816 }
1817
1818 static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
1819                                     struct drm_dp_mst_branch *mstb,
1820                                     int req_type, int seqno, bool broadcast)
1821 {
1822         struct drm_dp_sideband_msg_tx *txmsg;
1823
1824         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1825         if (!txmsg)
1826                 return -ENOMEM;
1827
1828         txmsg->dst = mstb;
1829         txmsg->seqno = seqno;
1830         drm_dp_encode_up_ack_reply(txmsg, req_type);
1831
1832         mutex_lock(&mgr->qlock);
1833         list_add_tail(&txmsg->next, &mgr->tx_msg_upq);
1834         if (!mgr->tx_up_in_progress) {
1835                 process_single_up_tx_qlock(mgr);
1836         }
1837         mutex_unlock(&mgr->qlock);
1838         return 0;
1839 }
1840
1841 static bool drm_dp_get_vc_payload_bw(int dp_link_bw,
1842                                      int dp_link_count,
1843                                      int *out)
1844 {
1845         switch (dp_link_bw) {
1846         default:
1847                 DRM_DEBUG_KMS("invalid link bandwidth in DPCD: %x (link count: %d)\n",
1848                               dp_link_bw, dp_link_count);
1849                 return false;
1850
1851         case DP_LINK_BW_1_62:
1852                 *out = 3 * dp_link_count;
1853                 break;
1854         case DP_LINK_BW_2_7:
1855                 *out = 5 * dp_link_count;
1856                 break;
1857         case DP_LINK_BW_5_4:
1858                 *out = 10 * dp_link_count;
1859                 break;
1860         }
1861         return true;
1862 }
1863
1864 /**
1865  * drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a topology manager
1866  * @mgr: manager to set state for
1867  * @mst_state: true to enable MST on this connector - false to disable.
1868  *
1869  * This is called by the driver when it detects an MST capable device plugged
1870  * into a DP MST capable port, or when a DP MST capable device is unplugged.
1871  */
1872 int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state)
1873 {
1874         int ret = 0;
1875         struct drm_dp_mst_branch *mstb = NULL;
1876
1877         mutex_lock(&mgr->lock);
1878         if (mst_state == mgr->mst_state)
1879                 goto out_unlock;
1880
1881         mgr->mst_state = mst_state;
1882         /* set the device into MST mode */
1883         if (mst_state) {
1884                 WARN_ON(mgr->mst_primary);
1885
1886                 /* get dpcd info */
1887                 ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd, DP_RECEIVER_CAP_SIZE);
1888                 if (ret != DP_RECEIVER_CAP_SIZE) {
1889                         DRM_DEBUG_KMS("failed to read DPCD\n");
1890                         goto out_unlock;
1891                 }
1892
1893                 if (!drm_dp_get_vc_payload_bw(mgr->dpcd[1],
1894                                               mgr->dpcd[2] & DP_MAX_LANE_COUNT_MASK,
1895                                               &mgr->pbn_div)) {
1896                         ret = -EINVAL;
1897                         goto out_unlock;
1898                 }
1899
1900                 mgr->total_pbn = 2560;
1901                 mgr->total_slots = DIV_ROUND_UP(mgr->total_pbn, mgr->pbn_div);
1902                 mgr->avail_slots = mgr->total_slots;
1903
1904                 /* add initial branch device at LCT 1 */
1905                 mstb = drm_dp_add_mst_branch_device(1, NULL);
1906                 if (mstb == NULL) {
1907                         ret = -ENOMEM;
1908                         goto out_unlock;
1909                 }
1910                 mstb->mgr = mgr;
1911
1912                 /* give this the main reference */
1913                 mgr->mst_primary = mstb;
1914                 kref_get(&mgr->mst_primary->kref);
1915
1916                 {
1917                         struct drm_dp_payload reset_pay;
1918                         reset_pay.start_slot = 0;
1919                         reset_pay.num_slots = 0x3f;
1920                         drm_dp_dpcd_write_payload(mgr, 0, &reset_pay);
1921                 }
1922
1923                 ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
1924                                          DP_MST_EN | DP_UP_REQ_EN | DP_UPSTREAM_IS_SRC);
1925                 if (ret < 0) {
1926                         goto out_unlock;
1927                 }
1928
1929
1930                 /* sort out guid */
1931                 ret = drm_dp_dpcd_read(mgr->aux, DP_GUID, mgr->guid, 16);
1932                 if (ret != 16) {
1933                         DRM_DEBUG_KMS("failed to read DP GUID %d\n", ret);
1934                         goto out_unlock;
1935                 }
1936
1937                 mgr->guid_valid = drm_dp_validate_guid(mgr, mgr->guid);
1938                 if (!mgr->guid_valid) {
1939                         ret = drm_dp_dpcd_write(mgr->aux, DP_GUID, mgr->guid, 16);
1940                         mgr->guid_valid = true;
1941                 }
1942
1943                 queue_work(system_long_wq, &mgr->work);
1944
1945                 ret = 0;
1946         } else {
1947                 /* disable MST on the device */
1948                 mstb = mgr->mst_primary;
1949                 mgr->mst_primary = NULL;
1950                 /* this can fail if the device is gone */
1951                 drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
1952                 ret = 0;
1953                 memset(mgr->payloads, 0, mgr->max_payloads * sizeof(struct drm_dp_payload));
1954                 mgr->payload_mask = 0;
1955                 set_bit(0, &mgr->payload_mask);
1956                 mgr->vcpi_mask = 0;
1957         }
1958
1959 out_unlock:
1960         mutex_unlock(&mgr->lock);
1961         if (mstb)
1962                 drm_dp_put_mst_branch_device(mstb);
1963         return ret;
1964
1965 }
1966 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_set_mst);
1967
1968 /**
1969  * drm_dp_mst_topology_mgr_suspend() - suspend the MST manager
1970  * @mgr: manager to suspend
1971  *
1972  * This function tells the MST device that we can't handle UP messages
1973  * anymore. This should stop it from sending any since we are suspended.
1974  */
1975 void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr)
1976 {
1977         mutex_lock(&mgr->lock);
1978         drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
1979                            DP_MST_EN | DP_UPSTREAM_IS_SRC);
1980         mutex_unlock(&mgr->lock);
1981 }
1982 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_suspend);
1983
1984 /**
1985  * drm_dp_mst_topology_mgr_resume() - resume the MST manager
1986  * @mgr: manager to resume
1987  *
1988  * This will fetch DPCD and see if the device is still there,
1989  * if it is, it will rewrite the MSTM control bits, and return.
1990  *
1991  * if the device fails this returns -1, and the driver should do
1992  * a full MST reprobe, in case we were undocked.
1993  */
1994 int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr)
1995 {
1996         int ret = 0;
1997
1998         mutex_lock(&mgr->lock);
1999
2000         if (mgr->mst_primary) {
2001                 int sret;
2002                 sret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd, DP_RECEIVER_CAP_SIZE);
2003                 if (sret != DP_RECEIVER_CAP_SIZE) {
2004                         DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
2005                         ret = -1;
2006                         goto out_unlock;
2007                 }
2008
2009                 ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
2010                                          DP_MST_EN | DP_UP_REQ_EN | DP_UPSTREAM_IS_SRC);
2011                 if (ret < 0) {
2012                         DRM_DEBUG_KMS("mst write failed - undocked during suspend?\n");
2013                         ret = -1;
2014                         goto out_unlock;
2015                 }
2016                 ret = 0;
2017         } else
2018                 ret = -1;
2019
2020 out_unlock:
2021         mutex_unlock(&mgr->lock);
2022         return ret;
2023 }
2024 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume);
2025
2026 static void drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up)
2027 {
2028         int len;
2029         u8 replyblock[32];
2030         int replylen, origlen, curreply;
2031         int ret;
2032         struct drm_dp_sideband_msg_rx *msg;
2033         int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE : DP_SIDEBAND_MSG_DOWN_REP_BASE;
2034         msg = up ? &mgr->up_req_recv : &mgr->down_rep_recv;
2035
2036         len = min(mgr->max_dpcd_transaction_bytes, 16);
2037         ret = drm_dp_dpcd_read(mgr->aux, basereg,
2038                                replyblock, len);
2039         if (ret != len) {
2040                 DRM_DEBUG_KMS("failed to read DPCD down rep %d %d\n", len, ret);
2041                 return;
2042         }
2043         ret = drm_dp_sideband_msg_build(msg, replyblock, len, true);
2044         if (!ret) {
2045                 DRM_DEBUG_KMS("sideband msg build failed %d\n", replyblock[0]);
2046                 return;
2047         }
2048         replylen = msg->curchunk_len + msg->curchunk_hdrlen;
2049
2050         origlen = replylen;
2051         replylen -= len;
2052         curreply = len;
2053         while (replylen > 0) {
2054                 len = min3(replylen, mgr->max_dpcd_transaction_bytes, 16);
2055                 ret = drm_dp_dpcd_read(mgr->aux, basereg + curreply,
2056                                     replyblock, len);
2057                 if (ret != len) {
2058                         DRM_DEBUG_KMS("failed to read a chunk\n");
2059                 }
2060                 ret = drm_dp_sideband_msg_build(msg, replyblock, len, false);
2061                 if (ret == false)
2062                         DRM_DEBUG_KMS("failed to build sideband msg\n");
2063                 curreply += len;
2064                 replylen -= len;
2065         }
2066 }
2067
2068 static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
2069 {
2070         int ret = 0;
2071
2072         drm_dp_get_one_sb_msg(mgr, false);
2073
2074         if (mgr->down_rep_recv.have_eomt) {
2075                 struct drm_dp_sideband_msg_tx *txmsg;
2076                 struct drm_dp_mst_branch *mstb;
2077                 int slot = -1;
2078                 mstb = drm_dp_get_mst_branch_device(mgr,
2079                                                     mgr->down_rep_recv.initial_hdr.lct,
2080                                                     mgr->down_rep_recv.initial_hdr.rad);
2081
2082                 if (!mstb) {
2083                         DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->down_rep_recv.initial_hdr.lct);
2084                         memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2085                         return 0;
2086                 }
2087
2088                 /* find the message */
2089                 slot = mgr->down_rep_recv.initial_hdr.seqno;
2090                 mutex_lock(&mgr->qlock);
2091                 txmsg = mstb->tx_slots[slot];
2092                 /* remove from slots */
2093                 mutex_unlock(&mgr->qlock);
2094
2095                 if (!txmsg) {
2096                         DRM_DEBUG_KMS("Got MST reply with no msg %p %d %d %02x %02x\n",
2097                                mstb,
2098                                mgr->down_rep_recv.initial_hdr.seqno,
2099                                mgr->down_rep_recv.initial_hdr.lct,
2100                                       mgr->down_rep_recv.initial_hdr.rad[0],
2101                                       mgr->down_rep_recv.msg[0]);
2102                         drm_dp_put_mst_branch_device(mstb);
2103                         memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2104                         return 0;
2105                 }
2106
2107                 drm_dp_sideband_parse_reply(&mgr->down_rep_recv, &txmsg->reply);
2108                 if (txmsg->reply.reply_type == 1) {
2109                         DRM_DEBUG_KMS("Got NAK reply: req 0x%02x, reason 0x%02x, nak data 0x%02x\n", txmsg->reply.req_type, txmsg->reply.u.nak.reason, txmsg->reply.u.nak.nak_data);
2110                 }
2111
2112                 memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2113                 drm_dp_put_mst_branch_device(mstb);
2114
2115                 mutex_lock(&mgr->qlock);
2116                 txmsg->state = DRM_DP_SIDEBAND_TX_RX;
2117                 mstb->tx_slots[slot] = NULL;
2118                 mutex_unlock(&mgr->qlock);
2119
2120                 wake_up(&mgr->tx_waitq);
2121         }
2122         return ret;
2123 }
2124
2125 static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
2126 {
2127         int ret = 0;
2128         drm_dp_get_one_sb_msg(mgr, true);
2129
2130         if (mgr->up_req_recv.have_eomt) {
2131                 struct drm_dp_sideband_msg_req_body msg;
2132                 struct drm_dp_mst_branch *mstb;
2133                 bool seqno;
2134                 mstb = drm_dp_get_mst_branch_device(mgr,
2135                                                     mgr->up_req_recv.initial_hdr.lct,
2136                                                     mgr->up_req_recv.initial_hdr.rad);
2137                 if (!mstb) {
2138                         DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
2139                         memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2140                         return 0;
2141                 }
2142
2143                 seqno = mgr->up_req_recv.initial_hdr.seqno;
2144                 drm_dp_sideband_parse_req(&mgr->up_req_recv, &msg);
2145
2146                 if (msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
2147                         drm_dp_send_up_ack_reply(mgr, mstb, msg.req_type, seqno, false);
2148                         drm_dp_update_port(mstb, &msg.u.conn_stat);
2149                         DRM_DEBUG_KMS("Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n", msg.u.conn_stat.port_number, msg.u.conn_stat.legacy_device_plug_status, msg.u.conn_stat.displayport_device_plug_status, msg.u.conn_stat.message_capability_status, msg.u.conn_stat.input_port, msg.u.conn_stat.peer_device_type);
2150                         (*mgr->cbs->hotplug)(mgr);
2151
2152                 } else if (msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
2153                         drm_dp_send_up_ack_reply(mgr, mstb, msg.req_type, seqno, false);
2154                         DRM_DEBUG_KMS("Got RSN: pn: %d avail_pbn %d\n", msg.u.resource_stat.port_number, msg.u.resource_stat.available_pbn);
2155                 }
2156
2157                 drm_dp_put_mst_branch_device(mstb);
2158                 memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2159         }
2160         return ret;
2161 }
2162
2163 /**
2164  * drm_dp_mst_hpd_irq() - MST hotplug IRQ notify
2165  * @mgr: manager to notify irq for.
2166  * @esi: 4 bytes from SINK_COUNT_ESI
2167  * @handled: whether the hpd interrupt was consumed or not
2168  *
2169  * This should be called from the driver when it detects a short IRQ,
2170  * along with the value of the DEVICE_SERVICE_IRQ_VECTOR_ESI0. The
2171  * topology manager will process the sideband messages received as a result
2172  * of this.
2173  */
2174 int drm_dp_mst_hpd_irq(struct drm_dp_mst_topology_mgr *mgr, u8 *esi, bool *handled)
2175 {
2176         int ret = 0;
2177         int sc;
2178         *handled = false;
2179         sc = esi[0] & 0x3f;
2180
2181         if (sc != mgr->sink_count) {
2182                 mgr->sink_count = sc;
2183                 *handled = true;
2184         }
2185
2186         if (esi[1] & DP_DOWN_REP_MSG_RDY) {
2187                 ret = drm_dp_mst_handle_down_rep(mgr);
2188                 *handled = true;
2189         }
2190
2191         if (esi[1] & DP_UP_REQ_MSG_RDY) {
2192                 ret |= drm_dp_mst_handle_up_req(mgr);
2193                 *handled = true;
2194         }
2195
2196         drm_dp_mst_kick_tx(mgr);
2197         return ret;
2198 }
2199 EXPORT_SYMBOL(drm_dp_mst_hpd_irq);
2200
2201 /**
2202  * drm_dp_mst_detect_port() - get connection status for an MST port
2203  * @mgr: manager for this port
2204  * @port: unverified pointer to a port
2205  *
2206  * This returns the current connection state for a port. It validates the
2207  * port pointer still exists so the caller doesn't require a reference
2208  */
2209 enum drm_connector_status drm_dp_mst_detect_port(struct drm_connector *connector,
2210                                                  struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2211 {
2212         enum drm_connector_status status = connector_status_disconnected;
2213
2214         /* we need to search for the port in the mgr in case its gone */
2215         port = drm_dp_get_validated_port_ref(mgr, port);
2216         if (!port)
2217                 return connector_status_disconnected;
2218
2219         if (!port->ddps)
2220                 goto out;
2221
2222         switch (port->pdt) {
2223         case DP_PEER_DEVICE_NONE:
2224         case DP_PEER_DEVICE_MST_BRANCHING:
2225                 break;
2226
2227         case DP_PEER_DEVICE_SST_SINK:
2228                 status = connector_status_connected;
2229                 /* for logical ports - cache the EDID */
2230                 if (port->port_num >= 8 && !port->cached_edid) {
2231                         port->cached_edid = drm_get_edid(connector, &port->aux.ddc);
2232                 }
2233                 break;
2234         case DP_PEER_DEVICE_DP_LEGACY_CONV:
2235                 if (port->ldps)
2236                         status = connector_status_connected;
2237                 break;
2238         }
2239 out:
2240         drm_dp_put_port(port);
2241         return status;
2242 }
2243 EXPORT_SYMBOL(drm_dp_mst_detect_port);
2244
2245 /**
2246  * drm_dp_mst_get_edid() - get EDID for an MST port
2247  * @connector: toplevel connector to get EDID for
2248  * @mgr: manager for this port
2249  * @port: unverified pointer to a port.
2250  *
2251  * This returns an EDID for the port connected to a connector,
2252  * It validates the pointer still exists so the caller doesn't require a
2253  * reference.
2254  */
2255 struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2256 {
2257         struct edid *edid = NULL;
2258
2259         /* we need to search for the port in the mgr in case its gone */
2260         port = drm_dp_get_validated_port_ref(mgr, port);
2261         if (!port)
2262                 return NULL;
2263
2264         if (port->cached_edid)
2265                 edid = drm_edid_duplicate(port->cached_edid);
2266         else
2267                 edid = drm_get_edid(connector, &port->aux.ddc);
2268
2269         drm_mode_connector_set_tile_property(connector);
2270         drm_dp_put_port(port);
2271         return edid;
2272 }
2273 EXPORT_SYMBOL(drm_dp_mst_get_edid);
2274
2275 /**
2276  * drm_dp_find_vcpi_slots() - find slots for this PBN value
2277  * @mgr: manager to use
2278  * @pbn: payload bandwidth to convert into slots.
2279  */
2280 int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
2281                            int pbn)
2282 {
2283         int num_slots;
2284
2285         num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
2286
2287         if (num_slots > mgr->avail_slots)
2288                 return -ENOSPC;
2289         return num_slots;
2290 }
2291 EXPORT_SYMBOL(drm_dp_find_vcpi_slots);
2292
2293 static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
2294                             struct drm_dp_vcpi *vcpi, int pbn)
2295 {
2296         int num_slots;
2297         int ret;
2298
2299         num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
2300
2301         if (num_slots > mgr->avail_slots)
2302                 return -ENOSPC;
2303
2304         vcpi->pbn = pbn;
2305         vcpi->aligned_pbn = num_slots * mgr->pbn_div;
2306         vcpi->num_slots = num_slots;
2307
2308         ret = drm_dp_mst_assign_payload_id(mgr, vcpi);
2309         if (ret < 0)
2310                 return ret;
2311         return 0;
2312 }
2313
2314 /**
2315  * drm_dp_mst_allocate_vcpi() - Allocate a virtual channel
2316  * @mgr: manager for this port
2317  * @port: port to allocate a virtual channel for.
2318  * @pbn: payload bandwidth number to request
2319  * @slots: returned number of slots for this PBN.
2320  */
2321 bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port, int pbn, int *slots)
2322 {
2323         int ret;
2324
2325         port = drm_dp_get_validated_port_ref(mgr, port);
2326         if (!port)
2327                 return false;
2328
2329         if (port->vcpi.vcpi > 0) {
2330                 DRM_DEBUG_KMS("payload: vcpi %d already allocated for pbn %d - requested pbn %d\n", port->vcpi.vcpi, port->vcpi.pbn, pbn);
2331                 if (pbn == port->vcpi.pbn) {
2332                         *slots = port->vcpi.num_slots;
2333                         return true;
2334                 }
2335         }
2336
2337         ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn);
2338         if (ret) {
2339                 DRM_DEBUG_KMS("failed to init vcpi %d %d %d\n", DIV_ROUND_UP(pbn, mgr->pbn_div), mgr->avail_slots, ret);
2340                 goto out;
2341         }
2342         DRM_DEBUG_KMS("initing vcpi for %d %d\n", pbn, port->vcpi.num_slots);
2343         *slots = port->vcpi.num_slots;
2344
2345         drm_dp_put_port(port);
2346         return true;
2347 out:
2348         return false;
2349 }
2350 EXPORT_SYMBOL(drm_dp_mst_allocate_vcpi);
2351
2352 int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2353 {
2354         int slots = 0;
2355         port = drm_dp_get_validated_port_ref(mgr, port);
2356         if (!port)
2357                 return slots;
2358
2359         slots = port->vcpi.num_slots;
2360         drm_dp_put_port(port);
2361         return slots;
2362 }
2363 EXPORT_SYMBOL(drm_dp_mst_get_vcpi_slots);
2364
2365 /**
2366  * drm_dp_mst_reset_vcpi_slots() - Reset number of slots to 0 for VCPI
2367  * @mgr: manager for this port
2368  * @port: unverified pointer to a port.
2369  *
2370  * This just resets the number of slots for the ports VCPI for later programming.
2371  */
2372 void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2373 {
2374         port = drm_dp_get_validated_port_ref(mgr, port);
2375         if (!port)
2376                 return;
2377         port->vcpi.num_slots = 0;
2378         drm_dp_put_port(port);
2379 }
2380 EXPORT_SYMBOL(drm_dp_mst_reset_vcpi_slots);
2381
2382 /**
2383  * drm_dp_mst_deallocate_vcpi() - deallocate a VCPI
2384  * @mgr: manager for this port
2385  * @port: unverified port to deallocate vcpi for
2386  */
2387 void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2388 {
2389         port = drm_dp_get_validated_port_ref(mgr, port);
2390         if (!port)
2391                 return;
2392
2393         drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
2394         port->vcpi.num_slots = 0;
2395         port->vcpi.pbn = 0;
2396         port->vcpi.aligned_pbn = 0;
2397         port->vcpi.vcpi = 0;
2398         drm_dp_put_port(port);
2399 }
2400 EXPORT_SYMBOL(drm_dp_mst_deallocate_vcpi);
2401
2402 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
2403                                      int id, struct drm_dp_payload *payload)
2404 {
2405         u8 payload_alloc[3], status;
2406         int ret;
2407         int retries = 0;
2408
2409         drm_dp_dpcd_writeb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS,
2410                            DP_PAYLOAD_TABLE_UPDATED);
2411
2412         payload_alloc[0] = id;
2413         payload_alloc[1] = payload->start_slot;
2414         payload_alloc[2] = payload->num_slots;
2415
2416         ret = drm_dp_dpcd_write(mgr->aux, DP_PAYLOAD_ALLOCATE_SET, payload_alloc, 3);
2417         if (ret != 3) {
2418                 DRM_DEBUG_KMS("failed to write payload allocation %d\n", ret);
2419                 goto fail;
2420         }
2421
2422 retry:
2423         ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
2424         if (ret < 0) {
2425                 DRM_DEBUG_KMS("failed to read payload table status %d\n", ret);
2426                 goto fail;
2427         }
2428
2429         if (!(status & DP_PAYLOAD_TABLE_UPDATED)) {
2430                 retries++;
2431                 if (retries < 20) {
2432                         usleep_range(10000, 20000);
2433                         goto retry;
2434                 }
2435                 DRM_DEBUG_KMS("status not set after read payload table status %d\n", status);
2436                 ret = -EINVAL;
2437                 goto fail;
2438         }
2439         ret = 0;
2440 fail:
2441         return ret;
2442 }
2443
2444
2445 /**
2446  * drm_dp_check_act_status() - Check ACT handled status.
2447  * @mgr: manager to use
2448  *
2449  * Check the payload status bits in the DPCD for ACT handled completion.
2450  */
2451 int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
2452 {
2453         u8 status;
2454         int ret;
2455         int count = 0;
2456
2457         do {
2458                 ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
2459
2460                 if (ret < 0) {
2461                         DRM_DEBUG_KMS("failed to read payload table status %d\n", ret);
2462                         goto fail;
2463                 }
2464
2465                 if (status & DP_PAYLOAD_ACT_HANDLED)
2466                         break;
2467                 count++;
2468                 udelay(100);
2469
2470         } while (count < 30);
2471
2472         if (!(status & DP_PAYLOAD_ACT_HANDLED)) {
2473                 DRM_DEBUG_KMS("failed to get ACT bit %d after %d retries\n", status, count);
2474                 ret = -EINVAL;
2475                 goto fail;
2476         }
2477         return 0;
2478 fail:
2479         return ret;
2480 }
2481 EXPORT_SYMBOL(drm_dp_check_act_status);
2482
2483 /**
2484  * drm_dp_calc_pbn_mode() - Calculate the PBN for a mode.
2485  * @clock: dot clock for the mode
2486  * @bpp: bpp for the mode.
2487  *
2488  * This uses the formula in the spec to calculate the PBN value for a mode.
2489  */
2490 int drm_dp_calc_pbn_mode(int clock, int bpp)
2491 {
2492         fixed20_12 pix_bw;
2493         fixed20_12 fbpp;
2494         fixed20_12 result;
2495         fixed20_12 margin, tmp;
2496         u32 res;
2497
2498         pix_bw.full = dfixed_const(clock);
2499         fbpp.full = dfixed_const(bpp);
2500         tmp.full = dfixed_const(8);
2501         fbpp.full = dfixed_div(fbpp, tmp);
2502
2503         result.full = dfixed_mul(pix_bw, fbpp);
2504         margin.full = dfixed_const(54);
2505         tmp.full = dfixed_const(64);
2506         margin.full = dfixed_div(margin, tmp);
2507         result.full = dfixed_div(result, margin);
2508
2509         margin.full = dfixed_const(1006);
2510         tmp.full = dfixed_const(1000);
2511         margin.full = dfixed_div(margin, tmp);
2512         result.full = dfixed_mul(result, margin);
2513
2514         result.full = dfixed_div(result, tmp);
2515         result.full = dfixed_ceil(result);
2516         res = dfixed_trunc(result);
2517         return res;
2518 }
2519 EXPORT_SYMBOL(drm_dp_calc_pbn_mode);
2520
2521 static int test_calc_pbn_mode(void)
2522 {
2523         int ret;
2524         ret = drm_dp_calc_pbn_mode(154000, 30);
2525         if (ret != 689)
2526                 return -EINVAL;
2527         ret = drm_dp_calc_pbn_mode(234000, 30);
2528         if (ret != 1047)
2529                 return -EINVAL;
2530         return 0;
2531 }
2532
2533 /* we want to kick the TX after we've ack the up/down IRQs. */
2534 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr)
2535 {
2536         queue_work(system_long_wq, &mgr->tx_work);
2537 }
2538
2539 static void drm_dp_mst_dump_mstb(struct seq_file *m,
2540                                  struct drm_dp_mst_branch *mstb)
2541 {
2542         struct drm_dp_mst_port *port;
2543         int tabs = mstb->lct;
2544         char prefix[10];
2545         int i;
2546
2547         for (i = 0; i < tabs; i++)
2548                 prefix[i] = '\t';
2549         prefix[i] = '\0';
2550
2551         seq_printf(m, "%smst: %p, %d\n", prefix, mstb, mstb->num_ports);
2552         list_for_each_entry(port, &mstb->ports, next) {
2553                 seq_printf(m, "%sport: %d: ddps: %d ldps: %d, %p, conn: %p\n", prefix, port->port_num, port->ddps, port->ldps, port, port->connector);
2554                 if (port->mstb)
2555                         drm_dp_mst_dump_mstb(m, port->mstb);
2556         }
2557 }
2558
2559 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
2560                                   char *buf)
2561 {
2562         int ret;
2563         int i;
2564         for (i = 0; i < 4; i++) {
2565                 ret = drm_dp_dpcd_read(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS + (i * 16), &buf[i * 16], 16);
2566                 if (ret != 16)
2567                         break;
2568         }
2569         if (i == 4)
2570                 return true;
2571         return false;
2572 }
2573
2574 /**
2575  * drm_dp_mst_dump_topology(): dump topology to seq file.
2576  * @m: seq_file to dump output to
2577  * @mgr: manager to dump current topology for.
2578  *
2579  * helper to dump MST topology to a seq file for debugfs.
2580  */
2581 void drm_dp_mst_dump_topology(struct seq_file *m,
2582                               struct drm_dp_mst_topology_mgr *mgr)
2583 {
2584         int i;
2585         struct drm_dp_mst_port *port;
2586         mutex_lock(&mgr->lock);
2587         if (mgr->mst_primary)
2588                 drm_dp_mst_dump_mstb(m, mgr->mst_primary);
2589
2590         /* dump VCPIs */
2591         mutex_unlock(&mgr->lock);
2592
2593         mutex_lock(&mgr->payload_lock);
2594         seq_printf(m, "vcpi: %lx %lx\n", mgr->payload_mask, mgr->vcpi_mask);
2595
2596         for (i = 0; i < mgr->max_payloads; i++) {
2597                 if (mgr->proposed_vcpis[i]) {
2598                         port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
2599                         seq_printf(m, "vcpi %d: %d %d %d\n", i, port->port_num, port->vcpi.vcpi, port->vcpi.num_slots);
2600                 } else
2601                         seq_printf(m, "vcpi %d:unsed\n", i);
2602         }
2603         for (i = 0; i < mgr->max_payloads; i++) {
2604                 seq_printf(m, "payload %d: %d, %d, %d\n",
2605                            i,
2606                            mgr->payloads[i].payload_state,
2607                            mgr->payloads[i].start_slot,
2608                            mgr->payloads[i].num_slots);
2609
2610
2611         }
2612         mutex_unlock(&mgr->payload_lock);
2613
2614         mutex_lock(&mgr->lock);
2615         if (mgr->mst_primary) {
2616                 u8 buf[64];
2617                 bool bret;
2618                 int ret;
2619                 ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, buf, DP_RECEIVER_CAP_SIZE);
2620                 seq_printf(m, "dpcd: ");
2621                 for (i = 0; i < DP_RECEIVER_CAP_SIZE; i++)
2622                         seq_printf(m, "%02x ", buf[i]);
2623                 seq_printf(m, "\n");
2624                 ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2);
2625                 seq_printf(m, "faux/mst: ");
2626                 for (i = 0; i < 2; i++)
2627                         seq_printf(m, "%02x ", buf[i]);
2628                 seq_printf(m, "\n");
2629                 ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1);
2630                 seq_printf(m, "mst ctrl: ");
2631                 for (i = 0; i < 1; i++)
2632                         seq_printf(m, "%02x ", buf[i]);
2633                 seq_printf(m, "\n");
2634
2635                 /* dump the standard OUI branch header */
2636                 ret = drm_dp_dpcd_read(mgr->aux, DP_BRANCH_OUI, buf, DP_BRANCH_OUI_HEADER_SIZE);
2637                 seq_printf(m, "branch oui: ");
2638                 for (i = 0; i < 0x3; i++)
2639                         seq_printf(m, "%02x", buf[i]);
2640                 seq_printf(m, " devid: ");
2641                 for (i = 0x3; i < 0x8; i++)
2642                         seq_printf(m, "%c", buf[i]);
2643                 seq_printf(m, " revision: hw: %x.%x sw: %x.%x", buf[0x9] >> 4, buf[0x9] & 0xf, buf[0xa], buf[0xb]);
2644                 seq_printf(m, "\n");
2645                 bret = dump_dp_payload_table(mgr, buf);
2646                 if (bret == true) {
2647                         seq_printf(m, "payload table: ");
2648                         for (i = 0; i < 63; i++)
2649                                 seq_printf(m, "%02x ", buf[i]);
2650                         seq_printf(m, "\n");
2651                 }
2652
2653         }
2654
2655         mutex_unlock(&mgr->lock);
2656
2657 }
2658 EXPORT_SYMBOL(drm_dp_mst_dump_topology);
2659
2660 static void drm_dp_tx_work(struct work_struct *work)
2661 {
2662         struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, tx_work);
2663
2664         mutex_lock(&mgr->qlock);
2665         if (mgr->tx_down_in_progress)
2666                 process_single_down_tx_qlock(mgr);
2667         mutex_unlock(&mgr->qlock);
2668 }
2669
2670 static void drm_dp_destroy_connector_work(struct work_struct *work)
2671 {
2672         struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, destroy_connector_work);
2673         struct drm_dp_mst_port *port;
2674
2675         /*
2676          * Not a regular list traverse as we have to drop the destroy
2677          * connector lock before destroying the connector, to avoid AB->BA
2678          * ordering between this lock and the config mutex.
2679          */
2680         for (;;) {
2681                 mutex_lock(&mgr->destroy_connector_lock);
2682                 port = list_first_entry_or_null(&mgr->destroy_connector_list, struct drm_dp_mst_port, next);
2683                 if (!port) {
2684                         mutex_unlock(&mgr->destroy_connector_lock);
2685                         break;
2686                 }
2687                 list_del(&port->next);
2688                 mutex_unlock(&mgr->destroy_connector_lock);
2689
2690                 mgr->cbs->destroy_connector(mgr, port->connector);
2691
2692                 drm_dp_port_teardown_pdt(port, port->pdt);
2693
2694                 if (!port->input && port->vcpi.vcpi > 0)
2695                         drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
2696                 kfree(port);
2697         }
2698 }
2699
2700 /**
2701  * drm_dp_mst_topology_mgr_init - initialise a topology manager
2702  * @mgr: manager struct to initialise
2703  * @dev: device providing this structure - for i2c addition.
2704  * @aux: DP helper aux channel to talk to this device
2705  * @max_dpcd_transaction_bytes: hw specific DPCD transaction limit
2706  * @max_payloads: maximum number of payloads this GPU can source
2707  * @conn_base_id: the connector object ID the MST device is connected to.
2708  *
2709  * Return 0 for success, or negative error code on failure
2710  */
2711 int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
2712                                  struct device *dev, struct drm_dp_aux *aux,
2713                                  int max_dpcd_transaction_bytes,
2714                                  int max_payloads, int conn_base_id)
2715 {
2716         mutex_init(&mgr->lock);
2717         mutex_init(&mgr->qlock);
2718         mutex_init(&mgr->payload_lock);
2719         mutex_init(&mgr->destroy_connector_lock);
2720         INIT_LIST_HEAD(&mgr->tx_msg_upq);
2721         INIT_LIST_HEAD(&mgr->tx_msg_downq);
2722         INIT_LIST_HEAD(&mgr->destroy_connector_list);
2723         INIT_WORK(&mgr->work, drm_dp_mst_link_probe_work);
2724         INIT_WORK(&mgr->tx_work, drm_dp_tx_work);
2725         INIT_WORK(&mgr->destroy_connector_work, drm_dp_destroy_connector_work);
2726         init_waitqueue_head(&mgr->tx_waitq);
2727         mgr->dev = dev;
2728         mgr->aux = aux;
2729         mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes;
2730         mgr->max_payloads = max_payloads;
2731         mgr->conn_base_id = conn_base_id;
2732         mgr->payloads = kcalloc(max_payloads, sizeof(struct drm_dp_payload), GFP_KERNEL);
2733         if (!mgr->payloads)
2734                 return -ENOMEM;
2735         mgr->proposed_vcpis = kcalloc(max_payloads, sizeof(struct drm_dp_vcpi *), GFP_KERNEL);
2736         if (!mgr->proposed_vcpis)
2737                 return -ENOMEM;
2738         set_bit(0, &mgr->payload_mask);
2739         test_calc_pbn_mode();
2740         return 0;
2741 }
2742 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_init);
2743
2744 /**
2745  * drm_dp_mst_topology_mgr_destroy() - destroy topology manager.
2746  * @mgr: manager to destroy
2747  */
2748 void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
2749 {
2750         flush_work(&mgr->destroy_connector_work);
2751         mutex_lock(&mgr->payload_lock);
2752         kfree(mgr->payloads);
2753         mgr->payloads = NULL;
2754         kfree(mgr->proposed_vcpis);
2755         mgr->proposed_vcpis = NULL;
2756         mutex_unlock(&mgr->payload_lock);
2757         mgr->dev = NULL;
2758         mgr->aux = NULL;
2759 }
2760 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy);
2761
2762 /* I2C device */
2763 static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
2764                                int num)
2765 {
2766         struct drm_dp_aux *aux = adapter->algo_data;
2767         struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port, aux);
2768         struct drm_dp_mst_branch *mstb;
2769         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2770         unsigned int i;
2771         bool reading = false;
2772         struct drm_dp_sideband_msg_req_body msg;
2773         struct drm_dp_sideband_msg_tx *txmsg = NULL;
2774         int ret;
2775
2776         mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
2777         if (!mstb)
2778                 return -EREMOTEIO;
2779
2780         /* construct i2c msg */
2781         /* see if last msg is a read */
2782         if (msgs[num - 1].flags & I2C_M_RD)
2783                 reading = true;
2784
2785         if (!reading) {
2786                 DRM_DEBUG_KMS("Unsupported I2C transaction for MST device\n");
2787                 ret = -EIO;
2788                 goto out;
2789         }
2790
2791         msg.req_type = DP_REMOTE_I2C_READ;
2792         msg.u.i2c_read.num_transactions = num - 1;
2793         msg.u.i2c_read.port_number = port->port_num;
2794         for (i = 0; i < num - 1; i++) {
2795                 msg.u.i2c_read.transactions[i].i2c_dev_id = msgs[i].addr;
2796                 msg.u.i2c_read.transactions[i].num_bytes = msgs[i].len;
2797                 msg.u.i2c_read.transactions[i].bytes = msgs[i].buf;
2798         }
2799         msg.u.i2c_read.read_i2c_device_id = msgs[num - 1].addr;
2800         msg.u.i2c_read.num_bytes_read = msgs[num - 1].len;
2801
2802         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2803         if (!txmsg) {
2804                 ret = -ENOMEM;
2805                 goto out;
2806         }
2807
2808         txmsg->dst = mstb;
2809         drm_dp_encode_sideband_req(&msg, txmsg);
2810
2811         drm_dp_queue_down_tx(mgr, txmsg);
2812
2813         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
2814         if (ret > 0) {
2815
2816                 if (txmsg->reply.reply_type == 1) { /* got a NAK back */
2817                         ret = -EREMOTEIO;
2818                         goto out;
2819                 }
2820                 if (txmsg->reply.u.remote_i2c_read_ack.num_bytes != msgs[num - 1].len) {
2821                         ret = -EIO;
2822                         goto out;
2823                 }
2824                 memcpy(msgs[num - 1].buf, txmsg->reply.u.remote_i2c_read_ack.bytes, msgs[num - 1].len);
2825                 ret = num;
2826         }
2827 out:
2828         kfree(txmsg);
2829         drm_dp_put_mst_branch_device(mstb);
2830         return ret;
2831 }
2832
2833 static u32 drm_dp_mst_i2c_functionality(struct i2c_adapter *adapter)
2834 {
2835         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
2836                I2C_FUNC_SMBUS_READ_BLOCK_DATA |
2837                I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
2838                I2C_FUNC_10BIT_ADDR;
2839 }
2840
2841 static const struct i2c_algorithm drm_dp_mst_i2c_algo = {
2842         .functionality = drm_dp_mst_i2c_functionality,
2843         .master_xfer = drm_dp_mst_i2c_xfer,
2844 };
2845
2846 /**
2847  * drm_dp_mst_register_i2c_bus() - register an I2C adapter for I2C-over-AUX
2848  * @aux: DisplayPort AUX channel
2849  *
2850  * Returns 0 on success or a negative error code on failure.
2851  */
2852 static int drm_dp_mst_register_i2c_bus(struct drm_dp_aux *aux)
2853 {
2854         aux->ddc.algo = &drm_dp_mst_i2c_algo;
2855         aux->ddc.algo_data = aux;
2856         aux->ddc.retries = 3;
2857
2858         aux->ddc.class = I2C_CLASS_DDC;
2859         aux->ddc.owner = THIS_MODULE;
2860         aux->ddc.dev.parent = aux->dev;
2861         aux->ddc.dev.of_node = aux->dev->of_node;
2862
2863         strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
2864                 sizeof(aux->ddc.name));
2865
2866         return i2c_add_adapter(&aux->ddc);
2867 }
2868
2869 /**
2870  * drm_dp_mst_unregister_i2c_bus() - unregister an I2C-over-AUX adapter
2871  * @aux: DisplayPort AUX channel
2872  */
2873 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_aux *aux)
2874 {
2875         i2c_del_adapter(&aux->ddc);
2876 }