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