drivers/gpu/drm/drm_dp_mst_topology.c

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