drivers/gpu/drm/drm_dp_mst_topology.c

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