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_mst_port *port);
  92 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port);
  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
 263         size += (hdr->lct / 2);
 264         return size;
 265 }
 266
 267 static void drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
 268                                            u8 *buf, int *len)
 269 {
 270         int idx = 0;
 271         int i;
 272         u8 crc4;
 273
 274         buf[idx++] = ((hdr->lct & 0xf) << 4) | (hdr->lcr & 0xf);
 275         for (i = 0; i < (hdr->lct / 2); i++)
 276                 buf[idx++] = hdr->rad[i];
 277         buf[idx++] = (hdr->broadcast << 7) | (hdr->path_msg << 6) |
 278                 (hdr->msg_len & 0x3f);
 279         buf[idx++] = (hdr->somt << 7) | (hdr->eomt << 6) | (hdr->seqno << 4);
 280
 281         crc4 = drm_dp_msg_header_crc4(buf, (idx * 2) - 1);
 282         buf[idx - 1] |= (crc4 & 0xf);
 283
 284         *len = idx;
 285 }
 286
 287 static bool drm_dp_decode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
 288                                            u8 *buf, int buflen, u8 *hdrlen)
 289 {
 290         u8 crc4;
 291         u8 len;
 292         int i;
 293         u8 idx;
 294
 295         if (buf[0] == 0)
 296                 return false;
 297         len = 3;
 298         len += ((buf[0] & 0xf0) >> 4) / 2;
 299         if (len > buflen)
 300                 return false;
 301         crc4 = drm_dp_msg_header_crc4(buf, (len * 2) - 1);
 302
 303         if ((crc4 & 0xf) != (buf[len - 1] & 0xf)) {
 304                 DRM_DEBUG_KMS("crc4 mismatch 0x%x 0x%x\n", crc4, buf[len - 1]);
 305                 return false;
 306         }
 307
 308         hdr->lct = (buf[0] & 0xf0) >> 4;
 309         hdr->lcr = (buf[0] & 0xf);
 310         idx = 1;
 311         for (i = 0; i < (hdr->lct / 2); i++)
 312                 hdr->rad[i] = buf[idx++];
 313         hdr->broadcast = (buf[idx] >> 7) & 0x1;
 314         hdr->path_msg = (buf[idx] >> 6) & 0x1;
 315         hdr->msg_len = buf[idx] & 0x3f;
 316         idx++;
 317         hdr->somt = (buf[idx] >> 7) & 0x1;
 318         hdr->eomt = (buf[idx] >> 6) & 0x1;
 319         hdr->seqno = (buf[idx] >> 4) & 0x1;
 320         idx++;
 321         *hdrlen = idx;
 322         return true;
 323 }
 324
 325 void
 326 drm_dp_encode_sideband_req(const struct drm_dp_sideband_msg_req_body *req,
 327                            struct drm_dp_sideband_msg_tx *raw)
 328 {
 329         int idx = 0;
 330         int i;
 331         u8 *buf = raw->msg;
 332
 333         buf[idx++] = req->req_type & 0x7f;
 334
 335         switch (req->req_type) {
 336         case DP_ENUM_PATH_RESOURCES:
 337         case DP_POWER_DOWN_PHY:
 338         case DP_POWER_UP_PHY:
 339                 buf[idx] = (req->u.port_num.port_number & 0xf) << 4;
 340                 idx++;
 341                 break;
 342         case DP_ALLOCATE_PAYLOAD:
 343                 buf[idx] = (req->u.allocate_payload.port_number & 0xf) << 4 |
 344                         (req->u.allocate_payload.number_sdp_streams & 0xf);
 345                 idx++;
 346                 buf[idx] = (req->u.allocate_payload.vcpi & 0x7f);
 347                 idx++;
 348                 buf[idx] = (req->u.allocate_payload.pbn >> 8);
 349                 idx++;
 350                 buf[idx] = (req->u.allocate_payload.pbn & 0xff);
 351                 idx++;
 352                 for (i = 0; i < req->u.allocate_payload.number_sdp_streams / 2; i++) {
 353                         buf[idx] = ((req->u.allocate_payload.sdp_stream_sink[i * 2] & 0xf) << 4) |
 354                                 (req->u.allocate_payload.sdp_stream_sink[i * 2 + 1] & 0xf);
 355                         idx++;
 356                 }
 357                 if (req->u.allocate_payload.number_sdp_streams & 1) {
 358                         i = req->u.allocate_payload.number_sdp_streams - 1;
 359                         buf[idx] = (req->u.allocate_payload.sdp_stream_sink[i] & 0xf) << 4;
 360                         idx++;
 361                 }
 362                 break;
 363         case DP_QUERY_PAYLOAD:
 364                 buf[idx] = (req->u.query_payload.port_number & 0xf) << 4;
 365                 idx++;
 366                 buf[idx] = (req->u.query_payload.vcpi & 0x7f);
 367                 idx++;
 368                 break;
 369         case DP_REMOTE_DPCD_READ:
 370                 buf[idx] = (req->u.dpcd_read.port_number & 0xf) << 4;
 371                 buf[idx] |= ((req->u.dpcd_read.dpcd_address & 0xf0000) >> 16) & 0xf;
 372                 idx++;
 373                 buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff00) >> 8;
 374                 idx++;
 375                 buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff);
 376                 idx++;
 377                 buf[idx] = (req->u.dpcd_read.num_bytes);
 378                 idx++;
 379                 break;
 380
 381         case DP_REMOTE_DPCD_WRITE:
 382                 buf[idx] = (req->u.dpcd_write.port_number & 0xf) << 4;
 383                 buf[idx] |= ((req->u.dpcd_write.dpcd_address & 0xf0000) >> 16) & 0xf;
 384                 idx++;
 385                 buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff00) >> 8;
 386                 idx++;
 387                 buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff);
 388                 idx++;
 389                 buf[idx] = (req->u.dpcd_write.num_bytes);
 390                 idx++;
 391                 memcpy(&buf[idx], req->u.dpcd_write.bytes, req->u.dpcd_write.num_bytes);
 392                 idx += req->u.dpcd_write.num_bytes;
 393                 break;
 394         case DP_REMOTE_I2C_READ:
 395                 buf[idx] = (req->u.i2c_read.port_number & 0xf) << 4;
 396                 buf[idx] |= (req->u.i2c_read.num_transactions & 0x3);
 397                 idx++;
 398                 for (i = 0; i < (req->u.i2c_read.num_transactions & 0x3); i++) {
 399                         buf[idx] = req->u.i2c_read.transactions[i].i2c_dev_id & 0x7f;
 400                         idx++;
 401                         buf[idx] = req->u.i2c_read.transactions[i].num_bytes;
 402                         idx++;
 403                         memcpy(&buf[idx], req->u.i2c_read.transactions[i].bytes, req->u.i2c_read.transactions[i].num_bytes);
 404                         idx += req->u.i2c_read.transactions[i].num_bytes;
 405
 406                         buf[idx] = (req->u.i2c_read.transactions[i].no_stop_bit & 0x1) << 4;
 407                         buf[idx] |= (req->u.i2c_read.transactions[i].i2c_transaction_delay & 0xf);
 408                         idx++;
 409                 }
 410                 buf[idx] = (req->u.i2c_read.read_i2c_device_id) & 0x7f;
 411                 idx++;
 412                 buf[idx] = (req->u.i2c_read.num_bytes_read);
 413                 idx++;
 414                 break;
 415
 416         case DP_REMOTE_I2C_WRITE:
 417                 buf[idx] = (req->u.i2c_write.port_number & 0xf) << 4;
 418                 idx++;
 419                 buf[idx] = (req->u.i2c_write.write_i2c_device_id) & 0x7f;
 420                 idx++;
 421                 buf[idx] = (req->u.i2c_write.num_bytes);
 422                 idx++;
 423                 memcpy(&buf[idx], req->u.i2c_write.bytes, req->u.i2c_write.num_bytes);
 424                 idx += req->u.i2c_write.num_bytes;
 425                 break;
 426         }
 427         raw->cur_len = idx;
 428 }
 429 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_encode_sideband_req);
 430
 431 /* Decode a sideband request we've encoded, mainly used for debugging */
 432 int
 433 drm_dp_decode_sideband_req(const struct drm_dp_sideband_msg_tx *raw,
 434                            struct drm_dp_sideband_msg_req_body *req)
 435 {
 436         const u8 *buf = raw->msg;
 437         int i, idx = 0;
 438
 439         req->req_type = buf[idx++] & 0x7f;
 440         switch (req->req_type) {
 441         case DP_ENUM_PATH_RESOURCES:
 442         case DP_POWER_DOWN_PHY:
 443         case DP_POWER_UP_PHY:
 444                 req->u.port_num.port_number = (buf[idx] >> 4) & 0xf;
 445                 break;
 446         case DP_ALLOCATE_PAYLOAD:
 447                 {
 448                         struct drm_dp_allocate_payload *a =
 449                                 &req->u.allocate_payload;
 450
 451                         a->number_sdp_streams = buf[idx] & 0xf;
 452                         a->port_number = (buf[idx] >> 4) & 0xf;
 453
 454                         WARN_ON(buf[++idx] & 0x80);
 455                         a->vcpi = buf[idx] & 0x7f;
 456
 457                         a->pbn = buf[++idx] << 8;
 458                         a->pbn |= buf[++idx];
 459
 460                         idx++;
 461                         for (i = 0; i < a->number_sdp_streams; i++) {
 462                                 a->sdp_stream_sink[i] =
 463                                         (buf[idx + (i / 2)] >> ((i % 2) ? 0 : 4)) & 0xf;
 464                         }
 465                 }
 466                 break;
 467         case DP_QUERY_PAYLOAD:
 468                 req->u.query_payload.port_number = (buf[idx] >> 4) & 0xf;
 469                 WARN_ON(buf[++idx] & 0x80);
 470                 req->u.query_payload.vcpi = buf[idx] & 0x7f;
 471                 break;
 472         case DP_REMOTE_DPCD_READ:
 473                 {
 474                         struct drm_dp_remote_dpcd_read *r = &req->u.dpcd_read;
 475
 476                         r->port_number = (buf[idx] >> 4) & 0xf;
 477
 478                         r->dpcd_address = (buf[idx] << 16) & 0xf0000;
 479                         r->dpcd_address |= (buf[++idx] << 8) & 0xff00;
 480                         r->dpcd_address |= buf[++idx] & 0xff;
 481
 482                         r->num_bytes = buf[++idx];
 483                 }
 484                 break;
 485         case DP_REMOTE_DPCD_WRITE:
 486                 {
 487                         struct drm_dp_remote_dpcd_write *w =
 488                                 &req->u.dpcd_write;
 489
 490                         w->port_number = (buf[idx] >> 4) & 0xf;
 491
 492                         w->dpcd_address = (buf[idx] << 16) & 0xf0000;
 493                         w->dpcd_address |= (buf[++idx] << 8) & 0xff00;
 494                         w->dpcd_address |= buf[++idx] & 0xff;
 495
 496                         w->num_bytes = buf[++idx];
 497
 498                         w->bytes = kmemdup(&buf[++idx], w->num_bytes,
 499                                            GFP_KERNEL);
 500                         if (!w->bytes)
 501                                 return -ENOMEM;
 502                 }
 503                 break;
 504         case DP_REMOTE_I2C_READ:
 505                 {
 506                         struct drm_dp_remote_i2c_read *r = &req->u.i2c_read;
 507                         struct drm_dp_remote_i2c_read_tx *tx;
 508                         bool failed = false;
 509
 510                         r->num_transactions = buf[idx] & 0x3;
 511                         r->port_number = (buf[idx] >> 4) & 0xf;
 512                         for (i = 0; i < r->num_transactions; i++) {
 513                                 tx = &r->transactions[i];
 514
 515                                 tx->i2c_dev_id = buf[++idx] & 0x7f;
 516                                 tx->num_bytes = buf[++idx];
 517                                 tx->bytes = kmemdup(&buf[++idx],
 518                                                     tx->num_bytes,
 519                                                     GFP_KERNEL);
 520                                 if (!tx->bytes) {
 521                                         failed = true;
 522                                         break;
 523                                 }
 524                                 idx += tx->num_bytes;
 525                                 tx->no_stop_bit = (buf[idx] >> 5) & 0x1;
 526                                 tx->i2c_transaction_delay = buf[idx] & 0xf;
 527                         }
 528
 529                         if (failed) {
 530                                 for (i = 0; i < r->num_transactions; i++) {
 531                                         tx = &r->transactions[i];
 532                                         kfree(tx->bytes);
 533                                 }
 534                                 return -ENOMEM;
 535                         }
 536
 537                         r->read_i2c_device_id = buf[++idx] & 0x7f;
 538                         r->num_bytes_read = buf[++idx];
 539                 }
 540                 break;
 541         case DP_REMOTE_I2C_WRITE:
 542                 {
 543                         struct drm_dp_remote_i2c_write *w = &req->u.i2c_write;
 544
 545                         w->port_number = (buf[idx] >> 4) & 0xf;
 546                         w->write_i2c_device_id = buf[++idx] & 0x7f;
 547                         w->num_bytes = buf[++idx];
 548                         w->bytes = kmemdup(&buf[++idx], w->num_bytes,
 549                                            GFP_KERNEL);
 550                         if (!w->bytes)
 551                                 return -ENOMEM;
 552                 }
 553                 break;
 554         }
 555
 556         return 0;
 557 }
 558 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_decode_sideband_req);
 559
 560 void
 561 drm_dp_dump_sideband_msg_req_body(const struct drm_dp_sideband_msg_req_body *req,
 562                                   int indent, struct drm_printer *printer)
 563 {
 564         int i;
 565
 566 #define P(f, ...) drm_printf_indent(printer, indent, f, ##__VA_ARGS__)
 567         if (req->req_type == DP_LINK_ADDRESS) {
 568                 /* No contents to print */
 569                 P("type=%s\n", drm_dp_mst_req_type_str(req->req_type));
 570                 return;
 571         }
 572
 573         P("type=%s contents:\n", drm_dp_mst_req_type_str(req->req_type));
 574         indent++;
 575
 576         switch (req->req_type) {
 577         case DP_ENUM_PATH_RESOURCES:
 578         case DP_POWER_DOWN_PHY:
 579         case DP_POWER_UP_PHY:
 580                 P("port=%d\n", req->u.port_num.port_number);
 581                 break;
 582         case DP_ALLOCATE_PAYLOAD:
 583                 P("port=%d vcpi=%d pbn=%d sdp_streams=%d %*ph\n",
 584                   req->u.allocate_payload.port_number,
 585                   req->u.allocate_payload.vcpi, req->u.allocate_payload.pbn,
 586                   req->u.allocate_payload.number_sdp_streams,
 587                   req->u.allocate_payload.number_sdp_streams,
 588                   req->u.allocate_payload.sdp_stream_sink);
 589                 break;
 590         case DP_QUERY_PAYLOAD:
 591                 P("port=%d vcpi=%d\n",
 592                   req->u.query_payload.port_number,
 593                   req->u.query_payload.vcpi);
 594                 break;
 595         case DP_REMOTE_DPCD_READ:
 596                 P("port=%d dpcd_addr=%05x len=%d\n",
 597                   req->u.dpcd_read.port_number, req->u.dpcd_read.dpcd_address,
 598                   req->u.dpcd_read.num_bytes);
 599                 break;
 600         case DP_REMOTE_DPCD_WRITE:
 601                 P("port=%d addr=%05x len=%d: %*ph\n",
 602                   req->u.dpcd_write.port_number,
 603                   req->u.dpcd_write.dpcd_address,
 604                   req->u.dpcd_write.num_bytes, req->u.dpcd_write.num_bytes,
 605                   req->u.dpcd_write.bytes);
 606                 break;
 607         case DP_REMOTE_I2C_READ:
 608                 P("port=%d num_tx=%d id=%d size=%d:\n",
 609                   req->u.i2c_read.port_number,
 610                   req->u.i2c_read.num_transactions,
 611                   req->u.i2c_read.read_i2c_device_id,
 612                   req->u.i2c_read.num_bytes_read);
 613
 614                 indent++;
 615                 for (i = 0; i < req->u.i2c_read.num_transactions; i++) {
 616                         const struct drm_dp_remote_i2c_read_tx *rtx =
 617                                 &req->u.i2c_read.transactions[i];
 618
 619                         P("%d: id=%03d size=%03d no_stop_bit=%d tx_delay=%03d: %*ph\n",
 620                           i, rtx->i2c_dev_id, rtx->num_bytes,
 621                           rtx->no_stop_bit, rtx->i2c_transaction_delay,
 622                           rtx->num_bytes, rtx->bytes);
 623                 }
 624                 break;
 625         case DP_REMOTE_I2C_WRITE:
 626                 P("port=%d id=%d size=%d: %*ph\n",
 627                   req->u.i2c_write.port_number,
 628                   req->u.i2c_write.write_i2c_device_id,
 629                   req->u.i2c_write.num_bytes, req->u.i2c_write.num_bytes,
 630                   req->u.i2c_write.bytes);
 631                 break;
 632         default:
 633                 P("???\n");
 634                 break;
 635         }
 636 #undef P
 637 }
 638 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_dump_sideband_msg_req_body);
 639
 640 static inline void
 641 drm_dp_mst_dump_sideband_msg_tx(struct drm_printer *p,
 642                                 const struct drm_dp_sideband_msg_tx *txmsg)
 643 {
 644         struct drm_dp_sideband_msg_req_body req;
 645         char buf[64];
 646         int ret;
 647         int i;
 648
 649         drm_dp_mst_rad_to_str(txmsg->dst->rad, txmsg->dst->lct, buf,
 650                               sizeof(buf));
 651         drm_printf(p, "txmsg cur_offset=%x cur_len=%x seqno=%x state=%s path_msg=%d dst=%s\n",
 652                    txmsg->cur_offset, txmsg->cur_len, txmsg->seqno,
 653                    drm_dp_mst_sideband_tx_state_str(txmsg->state),
 654                    txmsg->path_msg, buf);
 655
 656         ret = drm_dp_decode_sideband_req(txmsg, &req);
 657         if (ret) {
 658                 drm_printf(p, "<failed to decode sideband req: %d>\n", ret);
 659                 return;
 660         }
 661         drm_dp_dump_sideband_msg_req_body(&req, 1, p);
 662
 663         switch (req.req_type) {
 664         case DP_REMOTE_DPCD_WRITE:
 665                 kfree(req.u.dpcd_write.bytes);
 666                 break;
 667         case DP_REMOTE_I2C_READ:
 668                 for (i = 0; i < req.u.i2c_read.num_transactions; i++)
 669                         kfree(req.u.i2c_read.transactions[i].bytes);
 670                 break;
 671         case DP_REMOTE_I2C_WRITE:
 672                 kfree(req.u.i2c_write.bytes);
 673                 break;
 674         }
 675 }
 676
 677 static void drm_dp_crc_sideband_chunk_req(u8 *msg, u8 len)
 678 {
 679         u8 crc4;
 680
 681         crc4 = drm_dp_msg_data_crc4(msg, len);
 682         msg[len] = crc4;
 683 }
 684
 685 static void drm_dp_encode_sideband_reply(struct drm_dp_sideband_msg_reply_body *rep,
 686                                          struct drm_dp_sideband_msg_tx *raw)
 687 {
 688         int idx = 0;
 689         u8 *buf = raw->msg;
 690
 691         buf[idx++] = (rep->reply_type & 0x1) << 7 | (rep->req_type & 0x7f);
 692
 693         raw->cur_len = idx;
 694 }
 695
 696 static int drm_dp_sideband_msg_set_header(struct drm_dp_sideband_msg_rx *msg,
 697                                           struct drm_dp_sideband_msg_hdr *hdr,
 698                                           u8 hdrlen)
 699 {
 700         /*
 701          * ignore out-of-order messages or messages that are part of a
 702          * failed transaction
 703          */
 704         if (!hdr->somt && !msg->have_somt)
 705                 return false;
 706
 707         /* get length contained in this portion */
 708         msg->curchunk_idx = 0;
 709         msg->curchunk_len = hdr->msg_len;
 710         msg->curchunk_hdrlen = hdrlen;
 711
 712         /* we have already gotten an somt - don't bother parsing */
 713         if (hdr->somt && msg->have_somt)
 714                 return false;
 715
 716         if (hdr->somt) {
 717                 memcpy(&msg->initial_hdr, hdr,
 718                        sizeof(struct drm_dp_sideband_msg_hdr));
 719                 msg->have_somt = true;
 720         }
 721         if (hdr->eomt)
 722                 msg->have_eomt = true;
 723
 724         return true;
 725 }
 726
 727 /* this adds a chunk of msg to the builder to get the final msg */
 728 static bool drm_dp_sideband_append_payload(struct drm_dp_sideband_msg_rx *msg,
 729                                            u8 *replybuf, u8 replybuflen)
 730 {
 731         u8 crc4;
 732
 733         memcpy(&msg->chunk[msg->curchunk_idx], replybuf, replybuflen);
 734         msg->curchunk_idx += replybuflen;
 735
 736         if (msg->curchunk_idx >= msg->curchunk_len) {
 737                 /* do CRC */
 738                 crc4 = drm_dp_msg_data_crc4(msg->chunk, msg->curchunk_len - 1);
 739                 if (crc4 != msg->chunk[msg->curchunk_len - 1])
 740                         print_hex_dump(KERN_DEBUG, "wrong crc",
 741                                        DUMP_PREFIX_NONE, 16, 1,
 742                                        msg->chunk,  msg->curchunk_len, false);
 743                 /* copy chunk into bigger msg */
 744                 memcpy(&msg->msg[msg->curlen], msg->chunk, msg->curchunk_len - 1);
 745                 msg->curlen += msg->curchunk_len - 1;
 746         }
 747         return true;
 748 }
 749
 750 static bool drm_dp_sideband_parse_link_address(struct drm_dp_sideband_msg_rx *raw,
 751                                                struct drm_dp_sideband_msg_reply_body *repmsg)
 752 {
 753         int idx = 1;
 754         int i;
 755
 756         memcpy(repmsg->u.link_addr.guid, &raw->msg[idx], 16);
 757         idx += 16;
 758         repmsg->u.link_addr.nports = raw->msg[idx] & 0xf;
 759         idx++;
 760         if (idx > raw->curlen)
 761                 goto fail_len;
 762         for (i = 0; i < repmsg->u.link_addr.nports; i++) {
 763                 if (raw->msg[idx] & 0x80)
 764                         repmsg->u.link_addr.ports[i].input_port = 1;
 765
 766                 repmsg->u.link_addr.ports[i].peer_device_type = (raw->msg[idx] >> 4) & 0x7;
 767                 repmsg->u.link_addr.ports[i].port_number = (raw->msg[idx] & 0xf);
 768
 769                 idx++;
 770                 if (idx > raw->curlen)
 771                         goto fail_len;
 772                 repmsg->u.link_addr.ports[i].mcs = (raw->msg[idx] >> 7) & 0x1;
 773                 repmsg->u.link_addr.ports[i].ddps = (raw->msg[idx] >> 6) & 0x1;
 774                 if (repmsg->u.link_addr.ports[i].input_port == 0)
 775                         repmsg->u.link_addr.ports[i].legacy_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
 776                 idx++;
 777                 if (idx > raw->curlen)
 778                         goto fail_len;
 779                 if (repmsg->u.link_addr.ports[i].input_port == 0) {
 780                         repmsg->u.link_addr.ports[i].dpcd_revision = (raw->msg[idx]);
 781                         idx++;
 782                         if (idx > raw->curlen)
 783                                 goto fail_len;
 784                         memcpy(repmsg->u.link_addr.ports[i].peer_guid, &raw->msg[idx], 16);
 785                         idx += 16;
 786                         if (idx > raw->curlen)
 787                                 goto fail_len;
 788                         repmsg->u.link_addr.ports[i].num_sdp_streams = (raw->msg[idx] >> 4) & 0xf;
 789                         repmsg->u.link_addr.ports[i].num_sdp_stream_sinks = (raw->msg[idx] & 0xf);
 790                         idx++;
 791
 792                 }
 793                 if (idx > raw->curlen)
 794                         goto fail_len;
 795         }
 796
 797         return true;
 798 fail_len:
 799         DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
 800         return false;
 801 }
 802
 803 static bool drm_dp_sideband_parse_remote_dpcd_read(struct drm_dp_sideband_msg_rx *raw,
 804                                                    struct drm_dp_sideband_msg_reply_body *repmsg)
 805 {
 806         int idx = 1;
 807
 808         repmsg->u.remote_dpcd_read_ack.port_number = raw->msg[idx] & 0xf;
 809         idx++;
 810         if (idx > raw->curlen)
 811                 goto fail_len;
 812         repmsg->u.remote_dpcd_read_ack.num_bytes = raw->msg[idx];
 813         idx++;
 814         if (idx > raw->curlen)
 815                 goto fail_len;
 816
 817         memcpy(repmsg->u.remote_dpcd_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_dpcd_read_ack.num_bytes);
 818         return true;
 819 fail_len:
 820         DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
 821         return false;
 822 }
 823
 824 static bool drm_dp_sideband_parse_remote_dpcd_write(struct drm_dp_sideband_msg_rx *raw,
 825                                                       struct drm_dp_sideband_msg_reply_body *repmsg)
 826 {
 827         int idx = 1;
 828
 829         repmsg->u.remote_dpcd_write_ack.port_number = raw->msg[idx] & 0xf;
 830         idx++;
 831         if (idx > raw->curlen)
 832                 goto fail_len;
 833         return true;
 834 fail_len:
 835         DRM_DEBUG_KMS("parse length fail %d %d\n", idx, raw->curlen);
 836         return false;
 837 }
 838
 839 static bool drm_dp_sideband_parse_remote_i2c_read_ack(struct drm_dp_sideband_msg_rx *raw,
 840                                                       struct drm_dp_sideband_msg_reply_body *repmsg)
 841 {
 842         int idx = 1;
 843
 844         repmsg->u.remote_i2c_read_ack.port_number = (raw->msg[idx] & 0xf);
 845         idx++;
 846         if (idx > raw->curlen)
 847                 goto fail_len;
 848         repmsg->u.remote_i2c_read_ack.num_bytes = raw->msg[idx];
 849         idx++;
 850         /* TODO check */
 851         memcpy(repmsg->u.remote_i2c_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_i2c_read_ack.num_bytes);
 852         return true;
 853 fail_len:
 854         DRM_DEBUG_KMS("remote i2c reply parse length fail %d %d\n", idx, raw->curlen);
 855         return false;
 856 }
 857
 858 static bool drm_dp_sideband_parse_enum_path_resources_ack(struct drm_dp_sideband_msg_rx *raw,
 859                                                           struct drm_dp_sideband_msg_reply_body *repmsg)
 860 {
 861         int idx = 1;
 862
 863         repmsg->u.path_resources.port_number = (raw->msg[idx] >> 4) & 0xf;
 864         repmsg->u.path_resources.fec_capable = raw->msg[idx] & 0x1;
 865         idx++;
 866         if (idx > raw->curlen)
 867                 goto fail_len;
 868         repmsg->u.path_resources.full_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 869         idx += 2;
 870         if (idx > raw->curlen)
 871                 goto fail_len;
 872         repmsg->u.path_resources.avail_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 873         idx += 2;
 874         if (idx > raw->curlen)
 875                 goto fail_len;
 876         return true;
 877 fail_len:
 878         DRM_DEBUG_KMS("enum resource parse length fail %d %d\n", idx, raw->curlen);
 879         return false;
 880 }
 881
 882 static bool drm_dp_sideband_parse_allocate_payload_ack(struct drm_dp_sideband_msg_rx *raw,
 883                                                           struct drm_dp_sideband_msg_reply_body *repmsg)
 884 {
 885         int idx = 1;
 886
 887         repmsg->u.allocate_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
 888         idx++;
 889         if (idx > raw->curlen)
 890                 goto fail_len;
 891         repmsg->u.allocate_payload.vcpi = raw->msg[idx];
 892         idx++;
 893         if (idx > raw->curlen)
 894                 goto fail_len;
 895         repmsg->u.allocate_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 896         idx += 2;
 897         if (idx > raw->curlen)
 898                 goto fail_len;
 899         return true;
 900 fail_len:
 901         DRM_DEBUG_KMS("allocate payload parse length fail %d %d\n", idx, raw->curlen);
 902         return false;
 903 }
 904
 905 static bool drm_dp_sideband_parse_query_payload_ack(struct drm_dp_sideband_msg_rx *raw,
 906                                                     struct drm_dp_sideband_msg_reply_body *repmsg)
 907 {
 908         int idx = 1;
 909
 910         repmsg->u.query_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
 911         idx++;
 912         if (idx > raw->curlen)
 913                 goto fail_len;
 914         repmsg->u.query_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
 915         idx += 2;
 916         if (idx > raw->curlen)
 917                 goto fail_len;
 918         return true;
 919 fail_len:
 920         DRM_DEBUG_KMS("query payload parse length fail %d %d\n", idx, raw->curlen);
 921         return false;
 922 }
 923
 924 static bool drm_dp_sideband_parse_power_updown_phy_ack(struct drm_dp_sideband_msg_rx *raw,
 925                                                        struct drm_dp_sideband_msg_reply_body *repmsg)
 926 {
 927         int idx = 1;
 928
 929         repmsg->u.port_number.port_number = (raw->msg[idx] >> 4) & 0xf;
 930         idx++;
 931         if (idx > raw->curlen) {
 932                 DRM_DEBUG_KMS("power up/down phy parse length fail %d %d\n",
 933                               idx, raw->curlen);
 934                 return false;
 935         }
 936         return true;
 937 }
 938
 939 static bool drm_dp_sideband_parse_reply(struct drm_dp_sideband_msg_rx *raw,
 940                                         struct drm_dp_sideband_msg_reply_body *msg)
 941 {
 942         memset(msg, 0, sizeof(*msg));
 943         msg->reply_type = (raw->msg[0] & 0x80) >> 7;
 944         msg->req_type = (raw->msg[0] & 0x7f);
 945
 946         if (msg->reply_type == DP_SIDEBAND_REPLY_NAK) {
 947                 memcpy(msg->u.nak.guid, &raw->msg[1], 16);
 948                 msg->u.nak.reason = raw->msg[17];
 949                 msg->u.nak.nak_data = raw->msg[18];
 950                 return false;
 951         }
 952
 953         switch (msg->req_type) {
 954         case DP_LINK_ADDRESS:
 955                 return drm_dp_sideband_parse_link_address(raw, msg);
 956         case DP_QUERY_PAYLOAD:
 957                 return drm_dp_sideband_parse_query_payload_ack(raw, msg);
 958         case DP_REMOTE_DPCD_READ:
 959                 return drm_dp_sideband_parse_remote_dpcd_read(raw, msg);
 960         case DP_REMOTE_DPCD_WRITE:
 961                 return drm_dp_sideband_parse_remote_dpcd_write(raw, msg);
 962         case DP_REMOTE_I2C_READ:
 963                 return drm_dp_sideband_parse_remote_i2c_read_ack(raw, msg);
 964         case DP_ENUM_PATH_RESOURCES:
 965                 return drm_dp_sideband_parse_enum_path_resources_ack(raw, msg);
 966         case DP_ALLOCATE_PAYLOAD:
 967                 return drm_dp_sideband_parse_allocate_payload_ack(raw, msg);
 968         case DP_POWER_DOWN_PHY:
 969         case DP_POWER_UP_PHY:
 970                 return drm_dp_sideband_parse_power_updown_phy_ack(raw, msg);
 971         case DP_CLEAR_PAYLOAD_ID_TABLE:
 972                 return true; /* since there's nothing to parse */
 973         default:
 974                 DRM_ERROR("Got unknown reply 0x%02x (%s)\n", msg->req_type,
 975                           drm_dp_mst_req_type_str(msg->req_type));
 976                 return false;
 977         }
 978 }
 979
 980 static bool drm_dp_sideband_parse_connection_status_notify(struct drm_dp_sideband_msg_rx *raw,
 981                                                            struct drm_dp_sideband_msg_req_body *msg)
 982 {
 983         int idx = 1;
 984
 985         msg->u.conn_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
 986         idx++;
 987         if (idx > raw->curlen)
 988                 goto fail_len;
 989
 990         memcpy(msg->u.conn_stat.guid, &raw->msg[idx], 16);
 991         idx += 16;
 992         if (idx > raw->curlen)
 993                 goto fail_len;
 994
 995         msg->u.conn_stat.legacy_device_plug_status = (raw->msg[idx] >> 6) & 0x1;
 996         msg->u.conn_stat.displayport_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
 997         msg->u.conn_stat.message_capability_status = (raw->msg[idx] >> 4) & 0x1;
 998         msg->u.conn_stat.input_port = (raw->msg[idx] >> 3) & 0x1;
 999         msg->u.conn_stat.peer_device_type = (raw->msg[idx] & 0x7);
1000         idx++;
1001         return true;
1002 fail_len:
1003         DRM_DEBUG_KMS("connection status reply parse length fail %d %d\n", idx, raw->curlen);
1004         return false;
1005 }
1006
1007 static bool drm_dp_sideband_parse_resource_status_notify(struct drm_dp_sideband_msg_rx *raw,
1008                                                            struct drm_dp_sideband_msg_req_body *msg)
1009 {
1010         int idx = 1;
1011
1012         msg->u.resource_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1013         idx++;
1014         if (idx > raw->curlen)
1015                 goto fail_len;
1016
1017         memcpy(msg->u.resource_stat.guid, &raw->msg[idx], 16);
1018         idx += 16;
1019         if (idx > raw->curlen)
1020                 goto fail_len;
1021
1022         msg->u.resource_stat.available_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
1023         idx++;
1024         return true;
1025 fail_len:
1026         DRM_DEBUG_KMS("resource status reply parse length fail %d %d\n", idx, raw->curlen);
1027         return false;
1028 }
1029
1030 static bool drm_dp_sideband_parse_req(struct drm_dp_sideband_msg_rx *raw,
1031                                       struct drm_dp_sideband_msg_req_body *msg)
1032 {
1033         memset(msg, 0, sizeof(*msg));
1034         msg->req_type = (raw->msg[0] & 0x7f);
1035
1036         switch (msg->req_type) {
1037         case DP_CONNECTION_STATUS_NOTIFY:
1038                 return drm_dp_sideband_parse_connection_status_notify(raw, msg);
1039         case DP_RESOURCE_STATUS_NOTIFY:
1040                 return drm_dp_sideband_parse_resource_status_notify(raw, msg);
1041         default:
1042                 DRM_ERROR("Got unknown request 0x%02x (%s)\n", msg->req_type,
1043                           drm_dp_mst_req_type_str(msg->req_type));
1044                 return false;
1045         }
1046 }
1047
1048 static void build_dpcd_write(struct drm_dp_sideband_msg_tx *msg,
1049                              u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
1050 {
1051         struct drm_dp_sideband_msg_req_body req;
1052
1053         req.req_type = DP_REMOTE_DPCD_WRITE;
1054         req.u.dpcd_write.port_number = port_num;
1055         req.u.dpcd_write.dpcd_address = offset;
1056         req.u.dpcd_write.num_bytes = num_bytes;
1057         req.u.dpcd_write.bytes = bytes;
1058         drm_dp_encode_sideband_req(&req, msg);
1059 }
1060
1061 static void build_link_address(struct drm_dp_sideband_msg_tx *msg)
1062 {
1063         struct drm_dp_sideband_msg_req_body req;
1064
1065         req.req_type = DP_LINK_ADDRESS;
1066         drm_dp_encode_sideband_req(&req, msg);
1067 }
1068
1069 static void build_clear_payload_id_table(struct drm_dp_sideband_msg_tx *msg)
1070 {
1071         struct drm_dp_sideband_msg_req_body req;
1072
1073         req.req_type = DP_CLEAR_PAYLOAD_ID_TABLE;
1074         drm_dp_encode_sideband_req(&req, msg);
1075 }
1076
1077 static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg,
1078                                      int port_num)
1079 {
1080         struct drm_dp_sideband_msg_req_body req;
1081
1082         req.req_type = DP_ENUM_PATH_RESOURCES;
1083         req.u.port_num.port_number = port_num;
1084         drm_dp_encode_sideband_req(&req, msg);
1085         msg->path_msg = true;
1086         return 0;
1087 }
1088
1089 static void build_allocate_payload(struct drm_dp_sideband_msg_tx *msg,
1090                                    int port_num,
1091                                    u8 vcpi, uint16_t pbn,
1092                                    u8 number_sdp_streams,
1093                                    u8 *sdp_stream_sink)
1094 {
1095         struct drm_dp_sideband_msg_req_body req;
1096
1097         memset(&req, 0, sizeof(req));
1098         req.req_type = DP_ALLOCATE_PAYLOAD;
1099         req.u.allocate_payload.port_number = port_num;
1100         req.u.allocate_payload.vcpi = vcpi;
1101         req.u.allocate_payload.pbn = pbn;
1102         req.u.allocate_payload.number_sdp_streams = number_sdp_streams;
1103         memcpy(req.u.allocate_payload.sdp_stream_sink, sdp_stream_sink,
1104                    number_sdp_streams);
1105         drm_dp_encode_sideband_req(&req, msg);
1106         msg->path_msg = true;
1107 }
1108
1109 static void build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,
1110                                    int port_num, bool power_up)
1111 {
1112         struct drm_dp_sideband_msg_req_body req;
1113
1114         if (power_up)
1115                 req.req_type = DP_POWER_UP_PHY;
1116         else
1117                 req.req_type = DP_POWER_DOWN_PHY;
1118
1119         req.u.port_num.port_number = port_num;
1120         drm_dp_encode_sideband_req(&req, msg);
1121         msg->path_msg = true;
1122 }
1123
1124 static int drm_dp_mst_assign_payload_id(struct drm_dp_mst_topology_mgr *mgr,
1125                                         struct drm_dp_vcpi *vcpi)
1126 {
1127         int ret, vcpi_ret;
1128
1129         mutex_lock(&mgr->payload_lock);
1130         ret = find_first_zero_bit(&mgr->payload_mask, mgr->max_payloads + 1);
1131         if (ret > mgr->max_payloads) {
1132                 ret = -EINVAL;
1133                 DRM_DEBUG_KMS("out of payload ids %d\n", ret);
1134                 goto out_unlock;
1135         }
1136
1137         vcpi_ret = find_first_zero_bit(&mgr->vcpi_mask, mgr->max_payloads + 1);
1138         if (vcpi_ret > mgr->max_payloads) {
1139                 ret = -EINVAL;
1140                 DRM_DEBUG_KMS("out of vcpi ids %d\n", ret);
1141                 goto out_unlock;
1142         }
1143
1144         set_bit(ret, &mgr->payload_mask);
1145         set_bit(vcpi_ret, &mgr->vcpi_mask);
1146         vcpi->vcpi = vcpi_ret + 1;
1147         mgr->proposed_vcpis[ret - 1] = vcpi;
1148 out_unlock:
1149         mutex_unlock(&mgr->payload_lock);
1150         return ret;
1151 }
1152
1153 static void drm_dp_mst_put_payload_id(struct drm_dp_mst_topology_mgr *mgr,
1154                                       int vcpi)
1155 {
1156         int i;
1157
1158         if (vcpi == 0)
1159                 return;
1160
1161         mutex_lock(&mgr->payload_lock);
1162         DRM_DEBUG_KMS("putting payload %d\n", vcpi);
1163         clear_bit(vcpi - 1, &mgr->vcpi_mask);
1164
1165         for (i = 0; i < mgr->max_payloads; i++) {
1166                 if (mgr->proposed_vcpis[i] &&
1167                     mgr->proposed_vcpis[i]->vcpi == vcpi) {
1168                         mgr->proposed_vcpis[i] = NULL;
1169                         clear_bit(i + 1, &mgr->payload_mask);
1170                 }
1171         }
1172         mutex_unlock(&mgr->payload_lock);
1173 }
1174
1175 static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr,
1176                               struct drm_dp_sideband_msg_tx *txmsg)
1177 {
1178         unsigned int state;
1179
1180         /*
1181          * All updates to txmsg->state are protected by mgr->qlock, and the two
1182          * cases we check here are terminal states. For those the barriers
1183          * provided by the wake_up/wait_event pair are enough.
1184          */
1185         state = READ_ONCE(txmsg->state);
1186         return (state == DRM_DP_SIDEBAND_TX_RX ||
1187                 state == DRM_DP_SIDEBAND_TX_TIMEOUT);
1188 }
1189
1190 static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb,
1191                                     struct drm_dp_sideband_msg_tx *txmsg)
1192 {
1193         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1194         unsigned long wait_timeout = msecs_to_jiffies(4000);
1195         unsigned long wait_expires = jiffies + wait_timeout;
1196         int ret;
1197
1198         for (;;) {
1199                 /*
1200                  * If the driver provides a way for this, change to
1201                  * poll-waiting for the MST reply interrupt if we didn't receive
1202                  * it for 50 msec. This would cater for cases where the HPD
1203                  * pulse signal got lost somewhere, even though the sink raised
1204                  * the corresponding MST interrupt correctly. One example is the
1205                  * Club 3D CAC-1557 TypeC -> DP adapter which for some reason
1206                  * filters out short pulses with a duration less than ~540 usec.
1207                  *
1208                  * The poll period is 50 msec to avoid missing an interrupt
1209                  * after the sink has cleared it (after a 110msec timeout
1210                  * since it raised the interrupt).
1211                  */
1212                 ret = wait_event_timeout(mgr->tx_waitq,
1213                                          check_txmsg_state(mgr, txmsg),
1214                                          mgr->cbs->poll_hpd_irq ?
1215                                                 msecs_to_jiffies(50) :
1216                                                 wait_timeout);
1217
1218                 if (ret || !mgr->cbs->poll_hpd_irq ||
1219                     time_after(jiffies, wait_expires))
1220                         break;
1221
1222                 mgr->cbs->poll_hpd_irq(mgr);
1223         }
1224
1225         mutex_lock(&mgr->qlock);
1226         if (ret > 0) {
1227                 if (txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT) {
1228                         ret = -EIO;
1229                         goto out;
1230                 }
1231         } else {
1232                 DRM_DEBUG_KMS("timedout msg send %p %d %d\n", txmsg, txmsg->state, txmsg->seqno);
1233
1234                 /* dump some state */
1235                 ret = -EIO;
1236
1237                 /* remove from q */
1238                 if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED ||
1239                     txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND ||
1240                     txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
1241                         list_del(&txmsg->next);
1242         }
1243 out:
1244         if (unlikely(ret == -EIO) && drm_debug_enabled(DRM_UT_DP)) {
1245                 struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1246
1247                 drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
1248         }
1249         mutex_unlock(&mgr->qlock);
1250
1251         drm_dp_mst_kick_tx(mgr);
1252         return ret;
1253 }
1254
1255 static struct drm_dp_mst_branch *drm_dp_add_mst_branch_device(u8 lct, u8 *rad)
1256 {
1257         struct drm_dp_mst_branch *mstb;
1258
1259         mstb = kzalloc(sizeof(*mstb), GFP_KERNEL);
1260         if (!mstb)
1261                 return NULL;
1262
1263         mstb->lct = lct;
1264         if (lct > 1)
1265                 memcpy(mstb->rad, rad, lct / 2);
1266         INIT_LIST_HEAD(&mstb->ports);
1267         kref_init(&mstb->topology_kref);
1268         kref_init(&mstb->malloc_kref);
1269         return mstb;
1270 }
1271
1272 static void drm_dp_free_mst_branch_device(struct kref *kref)
1273 {
1274         struct drm_dp_mst_branch *mstb =
1275                 container_of(kref, struct drm_dp_mst_branch, malloc_kref);
1276
1277         if (mstb->port_parent)
1278                 drm_dp_mst_put_port_malloc(mstb->port_parent);
1279
1280         kfree(mstb);
1281 }
1282
1283 /**
1284  * DOC: Branch device and port refcounting
1285  *
1286  * Topology refcount overview
1287  * ~~~~~~~~~~~~~~~~~~~~~~~~~~
1288  *
1289  * The refcounting schemes for &struct drm_dp_mst_branch and &struct
1290  * drm_dp_mst_port are somewhat unusual. Both ports and branch devices have
1291  * two different kinds of refcounts: topology refcounts, and malloc refcounts.
1292  *
1293  * Topology refcounts are not exposed to drivers, and are handled internally
1294  * by the DP MST helpers. The helpers use them in order to prevent the
1295  * in-memory topology state from being changed in the middle of critical
1296  * operations like changing the internal state of payload allocations. This
1297  * means each branch and port will be considered to be connected to the rest
1298  * of the topology until its topology refcount reaches zero. Additionally,
1299  * for ports this means that their associated &struct drm_connector will stay
1300  * registered with userspace until the port's refcount reaches 0.
1301  *
1302  * Malloc refcount overview
1303  * ~~~~~~~~~~~~~~~~~~~~~~~~
1304  *
1305  * Malloc references are used to keep a &struct drm_dp_mst_port or &struct
1306  * drm_dp_mst_branch allocated even after all of its topology references have
1307  * been dropped, so that the driver or MST helpers can safely access each
1308  * branch's last known state before it was disconnected from the topology.
1309  * When the malloc refcount of a port or branch reaches 0, the memory
1310  * allocation containing the &struct drm_dp_mst_branch or &struct
1311  * drm_dp_mst_port respectively will be freed.
1312  *
1313  * For &struct drm_dp_mst_branch, malloc refcounts are not currently exposed
1314  * to drivers. As of writing this documentation, there are no drivers that
1315  * have a usecase for accessing &struct drm_dp_mst_branch outside of the MST
1316  * helpers. Exposing this API to drivers in a race-free manner would take more
1317  * tweaking of the refcounting scheme, however patches are welcome provided
1318  * there is a legitimate driver usecase for this.
1319  *
1320  * Refcount relationships in a topology
1321  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1322  *
1323  * Let's take a look at why the relationship between topology and malloc
1324  * refcounts is designed the way it is.
1325  *
1326  * .. kernel-figure:: dp-mst/topology-figure-1.dot
1327  *
1328  *    An example of topology and malloc refs in a DP MST topology with two
1329  *    active payloads. Topology refcount increments are indicated by solid
1330  *    lines, and malloc refcount increments are indicated by dashed lines.
1331  *    Each starts from the branch which incremented the refcount, and ends at
1332  *    the branch to which the refcount belongs to, i.e. the arrow points the
1333  *    same way as the C pointers used to reference a structure.
1334  *
1335  * As you can see in the above figure, every branch increments the topology
1336  * refcount of its children, and increments the malloc refcount of its
1337  * parent. Additionally, every payload increments the malloc refcount of its
1338  * assigned port by 1.
1339  *
1340  * So, what would happen if MSTB #3 from the above figure was unplugged from
1341  * the system, but the driver hadn't yet removed payload #2 from port #3? The
1342  * topology would start to look like the figure below.
1343  *
1344  * .. kernel-figure:: dp-mst/topology-figure-2.dot
1345  *
1346  *    Ports and branch devices which have been released from memory are
1347  *    colored grey, and references which have been removed are colored red.
1348  *
1349  * Whenever a port or branch device's topology refcount reaches zero, it will
1350  * decrement the topology refcounts of all its children, the malloc refcount
1351  * of its parent, and finally its own malloc refcount. For MSTB #4 and port
1352  * #4, this means they both have been disconnected from the topology and freed
1353  * from memory. But, because payload #2 is still holding a reference to port
1354  * #3, port #3 is removed from the topology but its &struct drm_dp_mst_port
1355  * is still accessible from memory. This also means port #3 has not yet
1356  * decremented the malloc refcount of MSTB #3, so its &struct
1357  * drm_dp_mst_branch will also stay allocated in memory until port #3's
1358  * malloc refcount reaches 0.
1359  *
1360  * This relationship is necessary because in order to release payload #2, we
1361  * need to be able to figure out the last relative of port #3 that's still
1362  * connected to the topology. In this case, we would travel up the topology as
1363  * shown below.
1364  *
1365  * .. kernel-figure:: dp-mst/topology-figure-3.dot
1366  *
1367  * And finally, remove payload #2 by communicating with port #2 through
1368  * sideband transactions.
1369  */
1370
1371 /**
1372  * drm_dp_mst_get_mstb_malloc() - Increment the malloc refcount of a branch
1373  * device
1374  * @mstb: The &struct drm_dp_mst_branch to increment the malloc refcount of
1375  *
1376  * Increments &drm_dp_mst_branch.malloc_kref. When
1377  * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1378  * will be released and @mstb may no longer be used.
1379  *
1380  * See also: drm_dp_mst_put_mstb_malloc()
1381  */
1382 static void
1383 drm_dp_mst_get_mstb_malloc(struct drm_dp_mst_branch *mstb)
1384 {
1385         kref_get(&mstb->malloc_kref);
1386         DRM_DEBUG("mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref));
1387 }
1388
1389 /**
1390  * drm_dp_mst_put_mstb_malloc() - Decrement the malloc refcount of a branch
1391  * device
1392  * @mstb: The &struct drm_dp_mst_branch to decrement the malloc refcount of
1393  *
1394  * Decrements &drm_dp_mst_branch.malloc_kref. When
1395  * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1396  * will be released and @mstb may no longer be used.
1397  *
1398  * See also: drm_dp_mst_get_mstb_malloc()
1399  */
1400 static void
1401 drm_dp_mst_put_mstb_malloc(struct drm_dp_mst_branch *mstb)
1402 {
1403         DRM_DEBUG("mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref) - 1);
1404         kref_put(&mstb->malloc_kref, drm_dp_free_mst_branch_device);
1405 }
1406
1407 static void drm_dp_free_mst_port(struct kref *kref)
1408 {
1409         struct drm_dp_mst_port *port =
1410                 container_of(kref, struct drm_dp_mst_port, malloc_kref);
1411
1412         drm_dp_mst_put_mstb_malloc(port->parent);
1413         kfree(port);
1414 }
1415
1416 /**
1417  * drm_dp_mst_get_port_malloc() - Increment the malloc refcount of an MST port
1418  * @port: The &struct drm_dp_mst_port to increment the malloc refcount of
1419  *
1420  * Increments &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1421  * reaches 0, the memory allocation for @port will be released and @port may
1422  * no longer be used.
1423  *
1424  * Because @port could potentially be freed at any time by the DP MST helpers
1425  * if &drm_dp_mst_port.malloc_kref reaches 0, including during a call to this
1426  * function, drivers that which to make use of &struct drm_dp_mst_port should
1427  * ensure that they grab at least one main malloc reference to their MST ports
1428  * in &drm_dp_mst_topology_cbs.add_connector. This callback is called before
1429  * there is any chance for &drm_dp_mst_port.malloc_kref to reach 0.
1430  *
1431  * See also: drm_dp_mst_put_port_malloc()
1432  */
1433 void
1434 drm_dp_mst_get_port_malloc(struct drm_dp_mst_port *port)
1435 {
1436         kref_get(&port->malloc_kref);
1437         DRM_DEBUG("port %p (%d)\n", port, kref_read(&port->malloc_kref));
1438 }
1439 EXPORT_SYMBOL(drm_dp_mst_get_port_malloc);
1440
1441 /**
1442  * drm_dp_mst_put_port_malloc() - Decrement the malloc refcount of an MST port
1443  * @port: The &struct drm_dp_mst_port to decrement the malloc refcount of
1444  *
1445  * Decrements &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1446  * reaches 0, the memory allocation for @port will be released and @port may
1447  * no longer be used.
1448  *
1449  * See also: drm_dp_mst_get_port_malloc()
1450  */
1451 void
1452 drm_dp_mst_put_port_malloc(struct drm_dp_mst_port *port)
1453 {
1454         DRM_DEBUG("port %p (%d)\n", port, kref_read(&port->malloc_kref) - 1);
1455         kref_put(&port->malloc_kref, drm_dp_free_mst_port);
1456 }
1457 EXPORT_SYMBOL(drm_dp_mst_put_port_malloc);
1458
1459 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
1460
1461 #define STACK_DEPTH 8
1462
1463 static noinline void
1464 __topology_ref_save(struct drm_dp_mst_topology_mgr *mgr,
1465                     struct drm_dp_mst_topology_ref_history *history,
1466                     enum drm_dp_mst_topology_ref_type type)
1467 {
1468         struct drm_dp_mst_topology_ref_entry *entry = NULL;
1469         depot_stack_handle_t backtrace;
1470         ulong stack_entries[STACK_DEPTH];
1471         uint n;
1472         int i;
1473
1474         n = stack_trace_save(stack_entries, ARRAY_SIZE(stack_entries), 1);
1475         backtrace = stack_depot_save(stack_entries, n, GFP_KERNEL);
1476         if (!backtrace)
1477                 return;
1478
1479         /* Try to find an existing entry for this backtrace */
1480         for (i = 0; i < history->len; i++) {
1481                 if (history->entries[i].backtrace == backtrace) {
1482                         entry = &history->entries[i];
1483                         break;
1484                 }
1485         }
1486
1487         /* Otherwise add one */
1488         if (!entry) {
1489                 struct drm_dp_mst_topology_ref_entry *new;
1490                 int new_len = history->len + 1;
1491
1492                 new = krealloc(history->entries, sizeof(*new) * new_len,
1493                                GFP_KERNEL);
1494                 if (!new)
1495                         return;
1496
1497                 entry = &new[history->len];
1498                 history->len = new_len;
1499                 history->entries = new;
1500
1501                 entry->backtrace = backtrace;
1502                 entry->type = type;
1503                 entry->count = 0;
1504         }
1505         entry->count++;
1506         entry->ts_nsec = ktime_get_ns();
1507 }
1508
1509 static int
1510 topology_ref_history_cmp(const void *a, const void *b)
1511 {
1512         const struct drm_dp_mst_topology_ref_entry *entry_a = a, *entry_b = b;
1513
1514         if (entry_a->ts_nsec > entry_b->ts_nsec)
1515                 return 1;
1516         else if (entry_a->ts_nsec < entry_b->ts_nsec)
1517                 return -1;
1518         else
1519                 return 0;
1520 }
1521
1522 static inline const char *
1523 topology_ref_type_to_str(enum drm_dp_mst_topology_ref_type type)
1524 {
1525         if (type == DRM_DP_MST_TOPOLOGY_REF_GET)
1526                 return "get";
1527         else
1528                 return "put";
1529 }
1530
1531 static void
1532 __dump_topology_ref_history(struct drm_dp_mst_topology_ref_history *history,
1533                             void *ptr, const char *type_str)
1534 {
1535         struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1536         char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
1537         int i;
1538
1539         if (!buf)
1540                 return;
1541
1542         if (!history->len)
1543                 goto out;
1544
1545         /* First, sort the list so that it goes from oldest to newest
1546          * reference entry
1547          */
1548         sort(history->entries, history->len, sizeof(*history->entries),
1549              topology_ref_history_cmp, NULL);
1550
1551         drm_printf(&p, "%s (%p) topology count reached 0, dumping history:\n",
1552                    type_str, ptr);
1553
1554         for (i = 0; i < history->len; i++) {
1555                 const struct drm_dp_mst_topology_ref_entry *entry =
1556                         &history->entries[i];
1557                 ulong *entries;
1558                 uint nr_entries;
1559                 u64 ts_nsec = entry->ts_nsec;
1560                 u32 rem_nsec = do_div(ts_nsec, 1000000000);
1561
1562                 nr_entries = stack_depot_fetch(entry->backtrace, &entries);
1563                 stack_trace_snprint(buf, PAGE_SIZE, entries, nr_entries, 4);
1564
1565                 drm_printf(&p, "  %d %ss (last at %5llu.%06u):\n%s",
1566                            entry->count,
1567                            topology_ref_type_to_str(entry->type),
1568                            ts_nsec, rem_nsec / 1000, buf);
1569         }
1570
1571         /* Now free the history, since this is the only time we expose it */
1572         kfree(history->entries);
1573 out:
1574         kfree(buf);
1575 }
1576
1577 static __always_inline void
1578 drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb)
1579 {
1580         __dump_topology_ref_history(&mstb->topology_ref_history, mstb,
1581                                     "MSTB");
1582 }
1583
1584 static __always_inline void
1585 drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port)
1586 {
1587         __dump_topology_ref_history(&port->topology_ref_history, port,
1588                                     "Port");
1589 }
1590
1591 static __always_inline void
1592 save_mstb_topology_ref(struct drm_dp_mst_branch *mstb,
1593                        enum drm_dp_mst_topology_ref_type type)
1594 {
1595         __topology_ref_save(mstb->mgr, &mstb->topology_ref_history, type);
1596 }
1597
1598 static __always_inline void
1599 save_port_topology_ref(struct drm_dp_mst_port *port,
1600                        enum drm_dp_mst_topology_ref_type type)
1601 {
1602         __topology_ref_save(port->mgr, &port->topology_ref_history, type);
1603 }
1604
1605 static inline void
1606 topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr)
1607 {
1608         mutex_lock(&mgr->topology_ref_history_lock);
1609 }
1610
1611 static inline void
1612 topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr)
1613 {
1614         mutex_unlock(&mgr->topology_ref_history_lock);
1615 }
1616 #else
1617 static inline void
1618 topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr) {}
1619 static inline void
1620 topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr) {}
1621 static inline void
1622 drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb) {}
1623 static inline void
1624 drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port) {}
1625 #define save_mstb_topology_ref(mstb, type)
1626 #define save_port_topology_ref(port, type)
1627 #endif
1628
1629 static void drm_dp_destroy_mst_branch_device(struct kref *kref)
1630 {
1631         struct drm_dp_mst_branch *mstb =
1632                 container_of(kref, struct drm_dp_mst_branch, topology_kref);
1633         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1634
1635         drm_dp_mst_dump_mstb_topology_history(mstb);
1636
1637         INIT_LIST_HEAD(&mstb->destroy_next);
1638
1639         /*
1640          * This can get called under mgr->mutex, so we need to perform the
1641          * actual destruction of the mstb in another worker
1642          */
1643         mutex_lock(&mgr->delayed_destroy_lock);
1644         list_add(&mstb->destroy_next, &mgr->destroy_branch_device_list);
1645         mutex_unlock(&mgr->delayed_destroy_lock);
1646         queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1647 }
1648
1649 /**
1650  * drm_dp_mst_topology_try_get_mstb() - Increment the topology refcount of a
1651  * branch device unless it's zero
1652  * @mstb: &struct drm_dp_mst_branch to increment the topology refcount of
1653  *
1654  * Attempts to grab a topology reference to @mstb, if it hasn't yet been
1655  * removed from the topology (e.g. &drm_dp_mst_branch.topology_kref has
1656  * reached 0). Holding a topology reference implies that a malloc reference
1657  * will be held to @mstb as long as the user holds the topology reference.
1658  *
1659  * Care should be taken to ensure that the user has at least one malloc
1660  * reference to @mstb. If you already have a topology reference to @mstb, you
1661  * should use drm_dp_mst_topology_get_mstb() instead.
1662  *
1663  * See also:
1664  * drm_dp_mst_topology_get_mstb()
1665  * drm_dp_mst_topology_put_mstb()
1666  *
1667  * Returns:
1668  * * 1: A topology reference was grabbed successfully
1669  * * 0: @port is no longer in the topology, no reference was grabbed
1670  */
1671 static int __must_check
1672 drm_dp_mst_topology_try_get_mstb(struct drm_dp_mst_branch *mstb)
1673 {
1674         int ret;
1675
1676         topology_ref_history_lock(mstb->mgr);
1677         ret = kref_get_unless_zero(&mstb->topology_kref);
1678         if (ret) {
1679                 DRM_DEBUG("mstb %p (%d)\n",
1680                           mstb, kref_read(&mstb->topology_kref));
1681                 save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1682         }
1683
1684         topology_ref_history_unlock(mstb->mgr);
1685
1686         return ret;
1687 }
1688
1689 /**
1690  * drm_dp_mst_topology_get_mstb() - Increment the topology refcount of a
1691  * branch device
1692  * @mstb: The &struct drm_dp_mst_branch to increment the topology refcount of
1693  *
1694  * Increments &drm_dp_mst_branch.topology_refcount without checking whether or
1695  * not it's already reached 0. This is only valid to use in scenarios where
1696  * you are already guaranteed to have at least one active topology reference
1697  * to @mstb. Otherwise, drm_dp_mst_topology_try_get_mstb() must be used.
1698  *
1699  * See also:
1700  * drm_dp_mst_topology_try_get_mstb()
1701  * drm_dp_mst_topology_put_mstb()
1702  */
1703 static void drm_dp_mst_topology_get_mstb(struct drm_dp_mst_branch *mstb)
1704 {
1705         topology_ref_history_lock(mstb->mgr);
1706
1707         save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1708         WARN_ON(kref_read(&mstb->topology_kref) == 0);
1709         kref_get(&mstb->topology_kref);
1710         DRM_DEBUG("mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1711
1712         topology_ref_history_unlock(mstb->mgr);
1713 }
1714
1715 /**
1716  * drm_dp_mst_topology_put_mstb() - release a topology reference to a branch
1717  * device
1718  * @mstb: The &struct drm_dp_mst_branch to release the topology reference from
1719  *
1720  * Releases a topology reference from @mstb by decrementing
1721  * &drm_dp_mst_branch.topology_kref.
1722  *
1723  * See also:
1724  * drm_dp_mst_topology_try_get_mstb()
1725  * drm_dp_mst_topology_get_mstb()
1726  */
1727 static void
1728 drm_dp_mst_topology_put_mstb(struct drm_dp_mst_branch *mstb)
1729 {
1730         topology_ref_history_lock(mstb->mgr);
1731
1732         DRM_DEBUG("mstb %p (%d)\n",
1733                   mstb, kref_read(&mstb->topology_kref) - 1);
1734         save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_PUT);
1735
1736         topology_ref_history_unlock(mstb->mgr);
1737         kref_put(&mstb->topology_kref, drm_dp_destroy_mst_branch_device);
1738 }
1739
1740 static void drm_dp_destroy_port(struct kref *kref)
1741 {
1742         struct drm_dp_mst_port *port =
1743                 container_of(kref, struct drm_dp_mst_port, topology_kref);
1744         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
1745
1746         drm_dp_mst_dump_port_topology_history(port);
1747
1748         /* There's nothing that needs locking to destroy an input port yet */
1749         if (port->input) {
1750                 drm_dp_mst_put_port_malloc(port);
1751                 return;
1752         }
1753
1754         kfree(port->cached_edid);
1755
1756         /*
1757          * we can't destroy the connector here, as we might be holding the
1758          * mode_config.mutex from an EDID retrieval
1759          */
1760         mutex_lock(&mgr->delayed_destroy_lock);
1761         list_add(&port->next, &mgr->destroy_port_list);
1762         mutex_unlock(&mgr->delayed_destroy_lock);
1763         queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1764 }
1765
1766 /**
1767  * drm_dp_mst_topology_try_get_port() - Increment the topology refcount of a
1768  * port unless it's zero
1769  * @port: &struct drm_dp_mst_port to increment the topology refcount of
1770  *
1771  * Attempts to grab a topology reference to @port, if it hasn't yet been
1772  * removed from the topology (e.g. &drm_dp_mst_port.topology_kref has reached
1773  * 0). Holding a topology reference implies that a malloc reference will be
1774  * held to @port as long as the user holds the topology reference.
1775  *
1776  * Care should be taken to ensure that the user has at least one malloc
1777  * reference to @port. If you already have a topology reference to @port, you
1778  * should use drm_dp_mst_topology_get_port() instead.
1779  *
1780  * See also:
1781  * drm_dp_mst_topology_get_port()
1782  * drm_dp_mst_topology_put_port()
1783  *
1784  * Returns:
1785  * * 1: A topology reference was grabbed successfully
1786  * * 0: @port is no longer in the topology, no reference was grabbed
1787  */
1788 static int __must_check
1789 drm_dp_mst_topology_try_get_port(struct drm_dp_mst_port *port)
1790 {
1791         int ret;
1792
1793         topology_ref_history_lock(port->mgr);
1794         ret = kref_get_unless_zero(&port->topology_kref);
1795         if (ret) {
1796                 DRM_DEBUG("port %p (%d)\n",
1797                           port, kref_read(&port->topology_kref));
1798                 save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1799         }
1800
1801         topology_ref_history_unlock(port->mgr);
1802         return ret;
1803 }
1804
1805 /**
1806  * drm_dp_mst_topology_get_port() - Increment the topology refcount of a port
1807  * @port: The &struct drm_dp_mst_port to increment the topology refcount of
1808  *
1809  * Increments &drm_dp_mst_port.topology_refcount without checking whether or
1810  * not it's already reached 0. This is only valid to use in scenarios where
1811  * you are already guaranteed to have at least one active topology reference
1812  * to @port. Otherwise, drm_dp_mst_topology_try_get_port() must be used.
1813  *
1814  * See also:
1815  * drm_dp_mst_topology_try_get_port()
1816  * drm_dp_mst_topology_put_port()
1817  */
1818 static void drm_dp_mst_topology_get_port(struct drm_dp_mst_port *port)
1819 {
1820         topology_ref_history_lock(port->mgr);
1821
1822         WARN_ON(kref_read(&port->topology_kref) == 0);
1823         kref_get(&port->topology_kref);
1824         DRM_DEBUG("port %p (%d)\n", port, kref_read(&port->topology_kref));
1825         save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1826
1827         topology_ref_history_unlock(port->mgr);
1828 }
1829
1830 /**
1831  * drm_dp_mst_topology_put_port() - release a topology reference to a port
1832  * @port: The &struct drm_dp_mst_port to release the topology reference from
1833  *
1834  * Releases a topology reference from @port by decrementing
1835  * &drm_dp_mst_port.topology_kref.
1836  *
1837  * See also:
1838  * drm_dp_mst_topology_try_get_port()
1839  * drm_dp_mst_topology_get_port()
1840  */
1841 static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port)
1842 {
1843         topology_ref_history_lock(port->mgr);
1844
1845         DRM_DEBUG("port %p (%d)\n",
1846                   port, kref_read(&port->topology_kref) - 1);
1847         save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_PUT);
1848
1849         topology_ref_history_unlock(port->mgr);
1850         kref_put(&port->topology_kref, drm_dp_destroy_port);
1851 }
1852
1853 static struct drm_dp_mst_branch *
1854 drm_dp_mst_topology_get_mstb_validated_locked(struct drm_dp_mst_branch *mstb,
1855                                               struct drm_dp_mst_branch *to_find)
1856 {
1857         struct drm_dp_mst_port *port;
1858         struct drm_dp_mst_branch *rmstb;
1859
1860         if (to_find == mstb)
1861                 return mstb;
1862
1863         list_for_each_entry(port, &mstb->ports, next) {
1864                 if (port->mstb) {
1865                         rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1866                             port->mstb, to_find);
1867                         if (rmstb)
1868                                 return rmstb;
1869                 }
1870         }
1871         return NULL;
1872 }
1873
1874 static struct drm_dp_mst_branch *
1875 drm_dp_mst_topology_get_mstb_validated(struct drm_dp_mst_topology_mgr *mgr,
1876                                        struct drm_dp_mst_branch *mstb)
1877 {
1878         struct drm_dp_mst_branch *rmstb = NULL;
1879
1880         mutex_lock(&mgr->lock);
1881         if (mgr->mst_primary) {
1882                 rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1883                     mgr->mst_primary, mstb);
1884
1885                 if (rmstb && !drm_dp_mst_topology_try_get_mstb(rmstb))
1886                         rmstb = NULL;
1887         }
1888         mutex_unlock(&mgr->lock);
1889         return rmstb;
1890 }
1891
1892 static struct drm_dp_mst_port *
1893 drm_dp_mst_topology_get_port_validated_locked(struct drm_dp_mst_branch *mstb,
1894                                               struct drm_dp_mst_port *to_find)
1895 {
1896         struct drm_dp_mst_port *port, *mport;
1897
1898         list_for_each_entry(port, &mstb->ports, next) {
1899                 if (port == to_find)
1900                         return port;
1901
1902                 if (port->mstb) {
1903                         mport = drm_dp_mst_topology_get_port_validated_locked(
1904                             port->mstb, to_find);
1905                         if (mport)
1906                                 return mport;
1907                 }
1908         }
1909         return NULL;
1910 }
1911
1912 static struct drm_dp_mst_port *
1913 drm_dp_mst_topology_get_port_validated(struct drm_dp_mst_topology_mgr *mgr,
1914                                        struct drm_dp_mst_port *port)
1915 {
1916         struct drm_dp_mst_port *rport = NULL;
1917
1918         mutex_lock(&mgr->lock);
1919         if (mgr->mst_primary) {
1920                 rport = drm_dp_mst_topology_get_port_validated_locked(
1921                     mgr->mst_primary, port);
1922
1923                 if (rport && !drm_dp_mst_topology_try_get_port(rport))
1924                         rport = NULL;
1925         }
1926         mutex_unlock(&mgr->lock);
1927         return rport;
1928 }
1929
1930 static struct drm_dp_mst_port *drm_dp_get_port(struct drm_dp_mst_branch *mstb, u8 port_num)
1931 {
1932         struct drm_dp_mst_port *port;
1933         int ret;
1934
1935         list_for_each_entry(port, &mstb->ports, next) {
1936                 if (port->port_num == port_num) {
1937                         ret = drm_dp_mst_topology_try_get_port(port);
1938                         return ret ? port : NULL;
1939                 }
1940         }
1941
1942         return NULL;
1943 }
1944
1945 /*
1946  * calculate a new RAD for this MST branch device
1947  * if parent has an LCT of 2 then it has 1 nibble of RAD,
1948  * if parent has an LCT of 3 then it has 2 nibbles of RAD,
1949  */
1950 static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port,
1951                                  u8 *rad)
1952 {
1953         int parent_lct = port->parent->lct;
1954         int shift = 4;
1955         int idx = (parent_lct - 1) / 2;
1956
1957         if (parent_lct > 1) {
1958                 memcpy(rad, port->parent->rad, idx + 1);
1959                 shift = (parent_lct % 2) ? 4 : 0;
1960         } else
1961                 rad[0] = 0;
1962
1963         rad[idx] |= port->port_num << shift;
1964         return parent_lct + 1;
1965 }
1966
1967 static bool drm_dp_mst_is_end_device(u8 pdt, bool mcs)
1968 {
1969         switch (pdt) {
1970         case DP_PEER_DEVICE_DP_LEGACY_CONV:
1971         case DP_PEER_DEVICE_SST_SINK:
1972                 return true;
1973         case DP_PEER_DEVICE_MST_BRANCHING:
1974                 /* For sst branch device */
1975                 if (!mcs)
1976                         return true;
1977
1978                 return false;
1979         }
1980         return true;
1981 }
1982
1983 static int
1984 drm_dp_port_set_pdt(struct drm_dp_mst_port *port, u8 new_pdt,
1985                     bool new_mcs)
1986 {
1987         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
1988         struct drm_dp_mst_branch *mstb;
1989         u8 rad[8], lct;
1990         int ret = 0;
1991
1992         if (port->pdt == new_pdt && port->mcs == new_mcs)
1993                 return 0;
1994
1995         /* Teardown the old pdt, if there is one */
1996         if (port->pdt != DP_PEER_DEVICE_NONE) {
1997                 if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
1998                         /*
1999                          * If the new PDT would also have an i2c bus,
2000                          * don't bother with reregistering it
2001                          */
2002                         if (new_pdt != DP_PEER_DEVICE_NONE &&
2003                             drm_dp_mst_is_end_device(new_pdt, new_mcs)) {
2004                                 port->pdt = new_pdt;
2005                                 port->mcs = new_mcs;
2006                                 return 0;
2007                         }
2008
2009                         /* remove i2c over sideband */
2010                         drm_dp_mst_unregister_i2c_bus(port);
2011                 } else {
2012                         mutex_lock(&mgr->lock);
2013                         drm_dp_mst_topology_put_mstb(port->mstb);
2014                         port->mstb = NULL;
2015                         mutex_unlock(&mgr->lock);
2016                 }
2017         }
2018
2019         port->pdt = new_pdt;
2020         port->mcs = new_mcs;
2021
2022         if (port->pdt != DP_PEER_DEVICE_NONE) {
2023                 if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2024                         /* add i2c over sideband */
2025                         ret = drm_dp_mst_register_i2c_bus(port);
2026                 } else {
2027                         lct = drm_dp_calculate_rad(port, rad);
2028                         mstb = drm_dp_add_mst_branch_device(lct, rad);
2029                         if (!mstb) {
2030                                 ret = -ENOMEM;
2031                                 DRM_ERROR("Failed to create MSTB for port %p",
2032                                           port);
2033                                 goto out;
2034                         }
2035
2036                         mutex_lock(&mgr->lock);
2037                         port->mstb = mstb;
2038                         mstb->mgr = port->mgr;
2039                         mstb->port_parent = port;
2040
2041                         /*
2042                          * Make sure this port's memory allocation stays
2043                          * around until its child MSTB releases it
2044                          */
2045                         drm_dp_mst_get_port_malloc(port);
2046                         mutex_unlock(&mgr->lock);
2047
2048                         /* And make sure we send a link address for this */
2049                         ret = 1;
2050                 }
2051         }
2052
2053 out:
2054         if (ret < 0)
2055                 port->pdt = DP_PEER_DEVICE_NONE;
2056         return ret;
2057 }
2058
2059 /**
2060  * drm_dp_mst_dpcd_read() - read a series of bytes from the DPCD via sideband
2061  * @aux: Fake sideband AUX CH
2062  * @offset: address of the (first) register to read
2063  * @buffer: buffer to store the register values
2064  * @size: number of bytes in @buffer
2065  *
2066  * Performs the same functionality for remote devices via
2067  * sideband messaging as drm_dp_dpcd_read() does for local
2068  * devices via actual AUX CH.
2069  *
2070  * Return: Number of bytes read, or negative error code on failure.
2071  */
2072 ssize_t drm_dp_mst_dpcd_read(struct drm_dp_aux *aux,
2073                              unsigned int offset, void *buffer, size_t size)
2074 {
2075         struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2076                                                     aux);
2077
2078         return drm_dp_send_dpcd_read(port->mgr, port,
2079                                      offset, size, buffer);
2080 }
2081
2082 /**
2083  * drm_dp_mst_dpcd_write() - write a series of bytes to the DPCD via sideband
2084  * @aux: Fake sideband AUX CH
2085  * @offset: address of the (first) register to write
2086  * @buffer: buffer containing the values to write
2087  * @size: number of bytes in @buffer
2088  *
2089  * Performs the same functionality for remote devices via
2090  * sideband messaging as drm_dp_dpcd_write() does for local
2091  * devices via actual AUX CH.
2092  *
2093  * Return: number of bytes written on success, negative error code on failure.
2094  */
2095 ssize_t drm_dp_mst_dpcd_write(struct drm_dp_aux *aux,
2096                               unsigned int offset, void *buffer, size_t size)
2097 {
2098         struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2099                                                     aux);
2100
2101         return drm_dp_send_dpcd_write(port->mgr, port,
2102                                       offset, size, buffer);
2103 }
2104
2105 static int drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid)
2106 {
2107         int ret = 0;
2108
2109         memcpy(mstb->guid, guid, 16);
2110
2111         if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) {
2112                 if (mstb->port_parent) {
2113                         ret = drm_dp_send_dpcd_write(mstb->mgr,
2114                                                      mstb->port_parent,
2115                                                      DP_GUID, 16, mstb->guid);
2116                 } else {
2117                         ret = drm_dp_dpcd_write(mstb->mgr->aux,
2118                                                 DP_GUID, mstb->guid, 16);
2119                 }
2120         }
2121
2122         if (ret < 16 && ret > 0)
2123                 return -EPROTO;
2124
2125         return ret == 16 ? 0 : ret;
2126 }
2127
2128 static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
2129                                 int pnum,
2130                                 char *proppath,
2131                                 size_t proppath_size)
2132 {
2133         int i;
2134         char temp[8];
2135
2136         snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id);
2137         for (i = 0; i < (mstb->lct - 1); i++) {
2138                 int shift = (i % 2) ? 0 : 4;
2139                 int port_num = (mstb->rad[i / 2] >> shift) & 0xf;
2140
2141                 snprintf(temp, sizeof(temp), "-%d", port_num);
2142                 strlcat(proppath, temp, proppath_size);
2143         }
2144         snprintf(temp, sizeof(temp), "-%d", pnum);
2145         strlcat(proppath, temp, proppath_size);
2146 }
2147
2148 /**
2149  * drm_dp_mst_connector_late_register() - Late MST connector registration
2150  * @connector: The MST connector
2151  * @port: The MST port for this connector
2152  *
2153  * Helper to register the remote aux device for this MST port. Drivers should
2154  * call this from their mst connector's late_register hook to enable MST aux
2155  * devices.
2156  *
2157  * Return: 0 on success, negative error code on failure.
2158  */
2159 int drm_dp_mst_connector_late_register(struct drm_connector *connector,
2160                                        struct drm_dp_mst_port *port)
2161 {
2162         DRM_DEBUG_KMS("registering %s remote bus for %s\n",
2163                       port->aux.name, connector->kdev->kobj.name);
2164
2165         port->aux.dev = connector->kdev;
2166         return drm_dp_aux_register_devnode(&port->aux);
2167 }
2168 EXPORT_SYMBOL(drm_dp_mst_connector_late_register);
2169
2170 /**
2171  * drm_dp_mst_connector_early_unregister() - Early MST connector unregistration
2172  * @connector: The MST connector
2173  * @port: The MST port for this connector
2174  *
2175  * Helper to unregister the remote aux device for this MST port, registered by
2176  * drm_dp_mst_connector_late_register(). Drivers should call this from their mst
2177  * connector's early_unregister hook.
2178  */
2179 void drm_dp_mst_connector_early_unregister(struct drm_connector *connector,
2180                                            struct drm_dp_mst_port *port)
2181 {
2182         DRM_DEBUG_KMS("unregistering %s remote bus for %s\n",
2183                       port->aux.name, connector->kdev->kobj.name);
2184         drm_dp_aux_unregister_devnode(&port->aux);
2185 }
2186 EXPORT_SYMBOL(drm_dp_mst_connector_early_unregister);
2187
2188 static void
2189 drm_dp_mst_port_add_connector(struct drm_dp_mst_branch *mstb,
2190                               struct drm_dp_mst_port *port)
2191 {
2192         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2193         char proppath[255];
2194         int ret;
2195
2196         build_mst_prop_path(mstb, port->port_num, proppath, sizeof(proppath));
2197         port->connector = mgr->cbs->add_connector(mgr, port, proppath);
2198         if (!port->connector) {
2199                 ret = -ENOMEM;
2200                 goto error;
2201         }
2202
2203         if (port->pdt != DP_PEER_DEVICE_NONE &&
2204             drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2205                 port->cached_edid = drm_get_edid(port->connector,
2206                                                  &port->aux.ddc);
2207                 drm_connector_set_tile_property(port->connector);
2208         }
2209
2210         drm_connector_register(port->connector);
2211         return;
2212
2213 error:
2214         DRM_ERROR("Failed to create connector for port %p: %d\n", port, ret);
2215 }
2216
2217 /*
2218  * Drop a topology reference, and unlink the port from the in-memory topology
2219  * layout
2220  */
2221 static void
2222 drm_dp_mst_topology_unlink_port(struct drm_dp_mst_topology_mgr *mgr,
2223                                 struct drm_dp_mst_port *port)
2224 {
2225         mutex_lock(&mgr->lock);
2226         port->parent->num_ports--;
2227         list_del(&port->next);
2228         mutex_unlock(&mgr->lock);
2229         drm_dp_mst_topology_put_port(port);
2230 }
2231
2232 static struct drm_dp_mst_port *
2233 drm_dp_mst_add_port(struct drm_device *dev,
2234                     struct drm_dp_mst_topology_mgr *mgr,
2235                     struct drm_dp_mst_branch *mstb, u8 port_number)
2236 {
2237         struct drm_dp_mst_port *port = kzalloc(sizeof(*port), GFP_KERNEL);
2238
2239         if (!port)
2240                 return NULL;
2241
2242         kref_init(&port->topology_kref);
2243         kref_init(&port->malloc_kref);
2244         port->parent = mstb;
2245         port->port_num = port_number;
2246         port->mgr = mgr;
2247         port->aux.name = "DPMST";
2248         port->aux.dev = dev->dev;
2249         port->aux.is_remote = true;
2250
2251         /* initialize the MST downstream port's AUX crc work queue */
2252         drm_dp_remote_aux_init(&port->aux);
2253
2254         /*
2255          * Make sure the memory allocation for our parent branch stays
2256          * around until our own memory allocation is released
2257          */
2258         drm_dp_mst_get_mstb_malloc(mstb);
2259
2260         return port;
2261 }
2262
2263 static int
2264 drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb,
2265                                     struct drm_device *dev,
2266                                     struct drm_dp_link_addr_reply_port *port_msg)
2267 {
2268         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2269         struct drm_dp_mst_port *port;
2270         int old_ddps = 0, ret;
2271         u8 new_pdt = DP_PEER_DEVICE_NONE;
2272         bool new_mcs = 0;
2273         bool created = false, send_link_addr = false, changed = false;
2274
2275         port = drm_dp_get_port(mstb, port_msg->port_number);
2276         if (!port) {
2277                 port = drm_dp_mst_add_port(dev, mgr, mstb,
2278                                            port_msg->port_number);
2279                 if (!port)
2280                         return -ENOMEM;
2281                 created = true;
2282                 changed = true;
2283         } else if (!port->input && port_msg->input_port && port->connector) {
2284                 /* Since port->connector can't be changed here, we create a
2285                  * new port if input_port changes from 0 to 1
2286                  */
2287                 drm_dp_mst_topology_unlink_port(mgr, port);
2288                 drm_dp_mst_topology_put_port(port);
2289                 port = drm_dp_mst_add_port(dev, mgr, mstb,
2290                                            port_msg->port_number);
2291                 if (!port)
2292                         return -ENOMEM;
2293                 changed = true;
2294                 created = true;
2295         } else if (port->input && !port_msg->input_port) {
2296                 changed = true;
2297         } else if (port->connector) {
2298                 /* We're updating a port that's exposed to userspace, so do it
2299                  * under lock
2300                  */
2301                 drm_modeset_lock(&mgr->base.lock, NULL);
2302
2303                 old_ddps = port->ddps;
2304                 changed = port->ddps != port_msg->ddps ||
2305                         (port->ddps &&
2306                          (port->ldps != port_msg->legacy_device_plug_status ||
2307                           port->dpcd_rev != port_msg->dpcd_revision ||
2308                           port->mcs != port_msg->mcs ||
2309                           port->pdt != port_msg->peer_device_type ||
2310                           port->num_sdp_stream_sinks !=
2311                           port_msg->num_sdp_stream_sinks));
2312         }
2313
2314         port->input = port_msg->input_port;
2315         if (!port->input)
2316                 new_pdt = port_msg->peer_device_type;
2317         new_mcs = port_msg->mcs;
2318         port->ddps = port_msg->ddps;
2319         port->ldps = port_msg->legacy_device_plug_status;
2320         port->dpcd_rev = port_msg->dpcd_revision;
2321         port->num_sdp_streams = port_msg->num_sdp_streams;
2322         port->num_sdp_stream_sinks = port_msg->num_sdp_stream_sinks;
2323
2324         /* manage mstb port lists with mgr lock - take a reference
2325            for this list */
2326         if (created) {
2327                 mutex_lock(&mgr->lock);
2328                 drm_dp_mst_topology_get_port(port);
2329                 list_add(&port->next, &mstb->ports);
2330                 mstb->num_ports++;
2331                 mutex_unlock(&mgr->lock);
2332         }
2333
2334         /*
2335          * Reprobe PBN caps on both hotplug, and when re-probing the link
2336          * for our parent mstb
2337          */
2338         if (old_ddps != port->ddps || !created) {
2339                 if (port->ddps && !port->input) {
2340                         ret = drm_dp_send_enum_path_resources(mgr, mstb,
2341                                                               port);
2342                         if (ret == 1)
2343                                 changed = true;
2344                 } else {
2345                         port->full_pbn = 0;
2346                 }
2347         }
2348
2349         ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2350         if (ret == 1) {
2351                 send_link_addr = true;
2352         } else if (ret < 0) {
2353                 DRM_ERROR("Failed to change PDT on port %p: %d\n",
2354                           port, ret);
2355                 goto fail;
2356         }
2357
2358         /*
2359          * If this port wasn't just created, then we're reprobing because
2360          * we're coming out of suspend. In this case, always resend the link
2361          * address if there's an MSTB on this port
2362          */
2363         if (!created && port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
2364             port->mcs)
2365                 send_link_addr = true;
2366
2367         if (port->connector)
2368                 drm_modeset_unlock(&mgr->base.lock);
2369         else if (!port->input)
2370                 drm_dp_mst_port_add_connector(mstb, port);
2371
2372         if (send_link_addr && port->mstb) {
2373                 ret = drm_dp_send_link_address(mgr, port->mstb);
2374                 if (ret == 1) /* MSTB below us changed */
2375                         changed = true;
2376                 else if (ret < 0)
2377                         goto fail_put;
2378         }
2379
2380         /* put reference to this port */
2381         drm_dp_mst_topology_put_port(port);
2382         return changed;
2383
2384 fail:
2385         drm_dp_mst_topology_unlink_port(mgr, port);
2386         if (port->connector)
2387                 drm_modeset_unlock(&mgr->base.lock);
2388 fail_put:
2389         drm_dp_mst_topology_put_port(port);
2390         return ret;
2391 }
2392
2393 static void
2394 drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
2395                             struct drm_dp_connection_status_notify *conn_stat)
2396 {
2397         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2398         struct drm_dp_mst_port *port;
2399         int old_ddps, old_input, ret, i;
2400         u8 new_pdt;
2401         bool new_mcs;
2402         bool dowork = false, create_connector = false;
2403
2404         port = drm_dp_get_port(mstb, conn_stat->port_number);
2405         if (!port)
2406                 return;
2407
2408         if (port->connector) {
2409                 if (!port->input && conn_stat->input_port) {
2410                         /*
2411                          * We can't remove a connector from an already exposed
2412                          * port, so just throw the port out and make sure we
2413                          * reprobe the link address of it's parent MSTB
2414                          */
2415                         drm_dp_mst_topology_unlink_port(mgr, port);
2416                         mstb->link_address_sent = false;
2417                         dowork = true;
2418                         goto out;
2419                 }
2420
2421                 /* Locking is only needed if the port's exposed to userspace */
2422                 drm_modeset_lock(&mgr->base.lock, NULL);
2423         } else if (port->input && !conn_stat->input_port) {
2424                 create_connector = true;
2425                 /* Reprobe link address so we get num_sdp_streams */
2426                 mstb->link_address_sent = false;
2427                 dowork = true;
2428         }
2429
2430         old_ddps = port->ddps;
2431         old_input = port->input;
2432         port->input = conn_stat->input_port;
2433         port->ldps = conn_stat->legacy_device_plug_status;
2434         port->ddps = conn_stat->displayport_device_plug_status;
2435
2436         if (old_ddps != port->ddps) {
2437                 if (port->ddps && !port->input)
2438                         drm_dp_send_enum_path_resources(mgr, mstb, port);
2439                 else
2440                         port->full_pbn = 0;
2441         }
2442
2443         new_pdt = port->input ? DP_PEER_DEVICE_NONE : conn_stat->peer_device_type;
2444         new_mcs = conn_stat->message_capability_status;
2445         ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2446         if (ret == 1) {
2447                 dowork = true;
2448         } else if (ret < 0) {
2449                 DRM_ERROR("Failed to change PDT for port %p: %d\n",
2450                           port, ret);
2451                 dowork = false;
2452         }
2453
2454         if (!old_input && old_ddps != port->ddps && !port->ddps) {
2455                 for (i = 0; i < mgr->max_payloads; i++) {
2456                         struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
2457                         struct drm_dp_mst_port *port_validated;
2458
2459                         if (!vcpi)
2460                                 continue;
2461
2462                         port_validated =
2463                                 container_of(vcpi, struct drm_dp_mst_port, vcpi);
2464                         port_validated =
2465                                 drm_dp_mst_topology_get_port_validated(mgr, port_validated);
2466                         if (!port_validated) {
2467                                 mutex_lock(&mgr->payload_lock);
2468                                 vcpi->num_slots = 0;
2469                                 mutex_unlock(&mgr->payload_lock);
2470                         } else {
2471                                 drm_dp_mst_topology_put_port(port_validated);
2472                         }
2473                 }
2474         }
2475
2476         if (port->connector)
2477                 drm_modeset_unlock(&mgr->base.lock);
2478         else if (create_connector)
2479                 drm_dp_mst_port_add_connector(mstb, port);
2480
2481 out:
2482         drm_dp_mst_topology_put_port(port);
2483         if (dowork)
2484                 queue_work(system_long_wq, &mstb->mgr->work);
2485 }
2486
2487 static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr *mgr,
2488                                                                u8 lct, u8 *rad)
2489 {
2490         struct drm_dp_mst_branch *mstb;
2491         struct drm_dp_mst_port *port;
2492         int i, ret;
2493         /* find the port by iterating down */
2494
2495         mutex_lock(&mgr->lock);
2496         mstb = mgr->mst_primary;
2497
2498         if (!mstb)
2499                 goto out;
2500
2501         for (i = 0; i < lct - 1; i++) {
2502                 int shift = (i % 2) ? 0 : 4;
2503                 int port_num = (rad[i / 2] >> shift) & 0xf;
2504
2505                 list_for_each_entry(port, &mstb->ports, next) {
2506                         if (port->port_num == port_num) {
2507                                 mstb = port->mstb;
2508                                 if (!mstb) {
2509                                         DRM_ERROR("failed to lookup MSTB with lct %d, rad %02x\n", lct, rad[0]);
2510                                         goto out;
2511                                 }
2512
2513                                 break;
2514                         }
2515                 }
2516         }
2517         ret = drm_dp_mst_topology_try_get_mstb(mstb);
2518         if (!ret)
2519                 mstb = NULL;
2520 out:
2521         mutex_unlock(&mgr->lock);
2522         return mstb;
2523 }
2524
2525 static struct drm_dp_mst_branch *get_mst_branch_device_by_guid_helper(
2526         struct drm_dp_mst_branch *mstb,
2527         const uint8_t *guid)
2528 {
2529         struct drm_dp_mst_branch *found_mstb;
2530         struct drm_dp_mst_port *port;
2531
2532         if (memcmp(mstb->guid, guid, 16) == 0)
2533                 return mstb;
2534
2535
2536         list_for_each_entry(port, &mstb->ports, next) {
2537                 if (!port->mstb)
2538                         continue;
2539
2540                 found_mstb = get_mst_branch_device_by_guid_helper(port->mstb, guid);
2541
2542                 if (found_mstb)
2543                         return found_mstb;
2544         }
2545
2546         return NULL;
2547 }
2548
2549 static struct drm_dp_mst_branch *
2550 drm_dp_get_mst_branch_device_by_guid(struct drm_dp_mst_topology_mgr *mgr,
2551                                      const uint8_t *guid)
2552 {
2553         struct drm_dp_mst_branch *mstb;
2554         int ret;
2555
2556         /* find the port by iterating down */
2557         mutex_lock(&mgr->lock);
2558
2559         mstb = get_mst_branch_device_by_guid_helper(mgr->mst_primary, guid);
2560         if (mstb) {
2561                 ret = drm_dp_mst_topology_try_get_mstb(mstb);
2562                 if (!ret)
2563                         mstb = NULL;
2564         }
2565
2566         mutex_unlock(&mgr->lock);
2567         return mstb;
2568 }
2569
2570 static int drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2571                                                struct drm_dp_mst_branch *mstb)
2572 {
2573         struct drm_dp_mst_port *port;
2574         int ret;
2575         bool changed = false;
2576
2577         if (!mstb->link_address_sent) {
2578                 ret = drm_dp_send_link_address(mgr, mstb);
2579                 if (ret == 1)
2580                         changed = true;
2581                 else if (ret < 0)
2582                         return ret;
2583         }
2584
2585         list_for_each_entry(port, &mstb->ports, next) {
2586                 struct drm_dp_mst_branch *mstb_child = NULL;
2587
2588                 if (port->input || !port->ddps)
2589                         continue;
2590
2591                 if (port->mstb)
2592                         mstb_child = drm_dp_mst_topology_get_mstb_validated(
2593                             mgr, port->mstb);
2594
2595                 if (mstb_child) {
2596                         ret = drm_dp_check_and_send_link_address(mgr,
2597                                                                  mstb_child);
2598                         drm_dp_mst_topology_put_mstb(mstb_child);
2599                         if (ret == 1)
2600                                 changed = true;
2601                         else if (ret < 0)
2602                                 return ret;
2603                 }
2604         }
2605
2606         return changed;
2607 }
2608
2609 static void drm_dp_mst_link_probe_work(struct work_struct *work)
2610 {
2611         struct drm_dp_mst_topology_mgr *mgr =
2612                 container_of(work, struct drm_dp_mst_topology_mgr, work);
2613         struct drm_device *dev = mgr->dev;
2614         struct drm_dp_mst_branch *mstb;
2615         int ret;
2616         bool clear_payload_id_table;
2617
2618         mutex_lock(&mgr->probe_lock);
2619
2620         mutex_lock(&mgr->lock);
2621         clear_payload_id_table = !mgr->payload_id_table_cleared;
2622         mgr->payload_id_table_cleared = true;
2623
2624         mstb = mgr->mst_primary;
2625         if (mstb) {
2626                 ret = drm_dp_mst_topology_try_get_mstb(mstb);
2627                 if (!ret)
2628                         mstb = NULL;
2629         }
2630         mutex_unlock(&mgr->lock);
2631         if (!mstb) {
2632                 mutex_unlock(&mgr->probe_lock);
2633                 return;
2634         }
2635
2636         /*
2637          * Certain branch devices seem to incorrectly report an available_pbn
2638          * of 0 on downstream sinks, even after clearing the
2639          * DP_PAYLOAD_ALLOCATE_* registers in
2640          * drm_dp_mst_topology_mgr_set_mst(). Namely, the CableMatters USB-C
2641          * 2x DP hub. Sending a CLEAR_PAYLOAD_ID_TABLE message seems to make
2642          * things work again.
2643          */
2644         if (clear_payload_id_table) {
2645                 DRM_DEBUG_KMS("Clearing payload ID table\n");
2646                 drm_dp_send_clear_payload_id_table(mgr, mstb);
2647         }
2648
2649         ret = drm_dp_check_and_send_link_address(mgr, mstb);
2650         drm_dp_mst_topology_put_mstb(mstb);
2651
2652         mutex_unlock(&mgr->probe_lock);
2653         if (ret)
2654                 drm_kms_helper_hotplug_event(dev);
2655 }
2656
2657 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
2658                                  u8 *guid)
2659 {
2660         u64 salt;
2661
2662         if (memchr_inv(guid, 0, 16))
2663                 return true;
2664
2665         salt = get_jiffies_64();
2666
2667         memcpy(&guid[0], &salt, sizeof(u64));
2668         memcpy(&guid[8], &salt, sizeof(u64));
2669
2670         return false;
2671 }
2672
2673 static void build_dpcd_read(struct drm_dp_sideband_msg_tx *msg,
2674                             u8 port_num, u32 offset, u8 num_bytes)
2675 {
2676         struct drm_dp_sideband_msg_req_body req;
2677
2678         req.req_type = DP_REMOTE_DPCD_READ;
2679         req.u.dpcd_read.port_number = port_num;
2680         req.u.dpcd_read.dpcd_address = offset;
2681         req.u.dpcd_read.num_bytes = num_bytes;
2682         drm_dp_encode_sideband_req(&req, msg);
2683 }
2684
2685 static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr,
2686                                     bool up, u8 *msg, int len)
2687 {
2688         int ret;
2689         int regbase = up ? DP_SIDEBAND_MSG_UP_REP_BASE : DP_SIDEBAND_MSG_DOWN_REQ_BASE;
2690         int tosend, total, offset;
2691         int retries = 0;
2692
2693 retry:
2694         total = len;
2695         offset = 0;
2696         do {
2697                 tosend = min3(mgr->max_dpcd_transaction_bytes, 16, total);
2698
2699                 ret = drm_dp_dpcd_write(mgr->aux, regbase + offset,
2700                                         &msg[offset],
2701                                         tosend);
2702                 if (ret != tosend) {
2703                         if (ret == -EIO && retries < 5) {
2704                                 retries++;
2705                                 goto retry;
2706                         }
2707                         DRM_DEBUG_KMS("failed to dpcd write %d %d\n", tosend, ret);
2708
2709                         return -EIO;
2710                 }
2711                 offset += tosend;
2712                 total -= tosend;
2713         } while (total > 0);
2714         return 0;
2715 }
2716
2717 static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr,
2718                                   struct drm_dp_sideband_msg_tx *txmsg)
2719 {
2720         struct drm_dp_mst_branch *mstb = txmsg->dst;
2721         u8 req_type;
2722
2723         req_type = txmsg->msg[0] & 0x7f;
2724         if (req_type == DP_CONNECTION_STATUS_NOTIFY ||
2725                 req_type == DP_RESOURCE_STATUS_NOTIFY)
2726                 hdr->broadcast = 1;
2727         else
2728                 hdr->broadcast = 0;
2729         hdr->path_msg = txmsg->path_msg;
2730         hdr->lct = mstb->lct;
2731         hdr->lcr = mstb->lct - 1;
2732         if (mstb->lct > 1)
2733                 memcpy(hdr->rad, mstb->rad, mstb->lct / 2);
2734
2735         return 0;
2736 }
2737 /*
2738  * process a single block of the next message in the sideband queue
2739  */
2740 static int process_single_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
2741                                    struct drm_dp_sideband_msg_tx *txmsg,
2742                                    bool up)
2743 {
2744         u8 chunk[48];
2745         struct drm_dp_sideband_msg_hdr hdr;
2746         int len, space, idx, tosend;
2747         int ret;
2748
2749         if (txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
2750                 return 0;
2751
2752         memset(&hdr, 0, sizeof(struct drm_dp_sideband_msg_hdr));
2753
2754         if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED)
2755                 txmsg->state = DRM_DP_SIDEBAND_TX_START_SEND;
2756
2757         /* make hdr from dst mst */
2758         ret = set_hdr_from_dst_qlock(&hdr, txmsg);
2759         if (ret < 0)
2760                 return ret;
2761
2762         /* amount left to send in this message */
2763         len = txmsg->cur_len - txmsg->cur_offset;
2764
2765         /* 48 - sideband msg size - 1 byte for data CRC, x header bytes */
2766         space = 48 - 1 - drm_dp_calc_sb_hdr_size(&hdr);
2767
2768         tosend = min(len, space);
2769         if (len == txmsg->cur_len)
2770                 hdr.somt = 1;
2771         if (space >= len)
2772                 hdr.eomt = 1;
2773
2774
2775         hdr.msg_len = tosend + 1;
2776         drm_dp_encode_sideband_msg_hdr(&hdr, chunk, &idx);
2777         memcpy(&chunk[idx], &txmsg->msg[txmsg->cur_offset], tosend);
2778         /* add crc at end */
2779         drm_dp_crc_sideband_chunk_req(&chunk[idx], tosend);
2780         idx += tosend + 1;
2781
2782         ret = drm_dp_send_sideband_msg(mgr, up, chunk, idx);
2783         if (unlikely(ret) && drm_debug_enabled(DRM_UT_DP)) {
2784                 struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2785
2786                 drm_printf(&p, "sideband msg failed to send\n");
2787                 drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2788                 return ret;
2789         }
2790
2791         txmsg->cur_offset += tosend;
2792         if (txmsg->cur_offset == txmsg->cur_len) {
2793                 txmsg->state = DRM_DP_SIDEBAND_TX_SENT;
2794                 return 1;
2795         }
2796         return 0;
2797 }
2798
2799 static void process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr *mgr)
2800 {
2801         struct drm_dp_sideband_msg_tx *txmsg;
2802         int ret;
2803
2804         WARN_ON(!mutex_is_locked(&mgr->qlock));
2805
2806         /* construct a chunk from the first msg in the tx_msg queue */
2807         if (list_empty(&mgr->tx_msg_downq))
2808                 return;
2809
2810         txmsg = list_first_entry(&mgr->tx_msg_downq,
2811                                  struct drm_dp_sideband_msg_tx, next);
2812         ret = process_single_tx_qlock(mgr, txmsg, false);
2813         if (ret < 0) {
2814                 DRM_DEBUG_KMS("failed to send msg in q %d\n", ret);
2815                 list_del(&txmsg->next);
2816                 txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
2817                 wake_up_all(&mgr->tx_waitq);
2818         }
2819 }
2820
2821 static void drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr *mgr,
2822                                  struct drm_dp_sideband_msg_tx *txmsg)
2823 {
2824         mutex_lock(&mgr->qlock);
2825         list_add_tail(&txmsg->next, &mgr->tx_msg_downq);
2826
2827         if (drm_debug_enabled(DRM_UT_DP)) {
2828                 struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2829
2830                 drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2831         }
2832
2833         if (list_is_singular(&mgr->tx_msg_downq))
2834                 process_single_down_tx_qlock(mgr);
2835         mutex_unlock(&mgr->qlock);
2836 }
2837
2838 static void
2839 drm_dp_dump_link_address(struct drm_dp_link_address_ack_reply *reply)
2840 {
2841         struct drm_dp_link_addr_reply_port *port_reply;
2842         int i;
2843
2844         for (i = 0; i < reply->nports; i++) {
2845                 port_reply = &reply->ports[i];
2846                 DRM_DEBUG_KMS("port %d: input %d, pdt: %d, pn: %d, dpcd_rev: %02x, mcs: %d, ddps: %d, ldps %d, sdp %d/%d\n",
2847                               i,
2848                               port_reply->input_port,
2849                               port_reply->peer_device_type,
2850                               port_reply->port_number,
2851                               port_reply->dpcd_revision,
2852                               port_reply->mcs,
2853                               port_reply->ddps,
2854                               port_reply->legacy_device_plug_status,
2855                               port_reply->num_sdp_streams,
2856                               port_reply->num_sdp_stream_sinks);
2857         }
2858 }
2859
2860 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2861                                      struct drm_dp_mst_branch *mstb)
2862 {
2863         struct drm_dp_sideband_msg_tx *txmsg;
2864         struct drm_dp_link_address_ack_reply *reply;
2865         struct drm_dp_mst_port *port, *tmp;
2866         int i, ret, port_mask = 0;
2867         bool changed = false;
2868
2869         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2870         if (!txmsg)
2871                 return -ENOMEM;
2872
2873         txmsg->dst = mstb;
2874         build_link_address(txmsg);
2875
2876         mstb->link_address_sent = true;
2877         drm_dp_queue_down_tx(mgr, txmsg);
2878
2879         /* FIXME: Actually do some real error handling here */
2880         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
2881         if (ret <= 0) {
2882                 DRM_ERROR("Sending link address failed with %d\n", ret);
2883                 goto out;
2884         }
2885         if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
2886                 DRM_ERROR("link address NAK received\n");
2887                 ret = -EIO;
2888                 goto out;
2889         }
2890
2891         reply = &txmsg->reply.u.link_addr;
2892         DRM_DEBUG_KMS("link address reply: %d\n", reply->nports);
2893         drm_dp_dump_link_address(reply);
2894
2895         ret = drm_dp_check_mstb_guid(mstb, reply->guid);
2896         if (ret) {
2897                 char buf[64];
2898
2899                 drm_dp_mst_rad_to_str(mstb->rad, mstb->lct, buf, sizeof(buf));
2900                 DRM_ERROR("GUID check on %s failed: %d\n",
2901                           buf, ret);
2902                 goto out;
2903         }
2904
2905         for (i = 0; i < reply->nports; i++) {
2906                 port_mask |= BIT(reply->ports[i].port_number);
2907                 ret = drm_dp_mst_handle_link_address_port(mstb, mgr->dev,
2908                                                           &reply->ports[i]);
2909                 if (ret == 1)
2910                         changed = true;
2911                 else if (ret < 0)
2912                         goto out;
2913         }
2914
2915         /* Prune any ports that are currently a part of mstb in our in-memory
2916          * topology, but were not seen in this link address. Usually this
2917          * means that they were removed while the topology was out of sync,
2918          * e.g. during suspend/resume
2919          */
2920         mutex_lock(&mgr->lock);
2921         list_for_each_entry_safe(port, tmp, &mstb->ports, next) {
2922                 if (port_mask & BIT(port->port_num))
2923                         continue;
2924
2925                 DRM_DEBUG_KMS("port %d was not in link address, removing\n",
2926                               port->port_num);
2927                 list_del(&port->next);
2928                 drm_dp_mst_topology_put_port(port);
2929                 changed = true;
2930         }
2931         mutex_unlock(&mgr->lock);
2932
2933 out:
2934         if (ret <= 0)
2935                 mstb->link_address_sent = false;
2936         kfree(txmsg);
2937         return ret < 0 ? ret : changed;
2938 }
2939
2940 static void
2941 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
3178         ret = drm_dp_payload_send_msg(mgr, port, id, port->vcpi.pbn);
3179         if (ret < 0)
3180                 return ret;
3181         payload->payload_state = DP_PAYLOAD_REMOTE;
3182         return ret;
3183 }
3184
3185 static int drm_dp_destroy_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
3186                                         struct drm_dp_mst_port *port,
3187                                         int id,
3188                                         struct drm_dp_payload *payload)
3189 {
3190         DRM_DEBUG_KMS("\n");
3191         /* it's okay for these to fail */
3192         if (port) {
3193                 drm_dp_payload_send_msg(mgr, port, id, 0);
3194         }
3195
3196         drm_dp_dpcd_write_payload(mgr, id, payload);
3197         payload->payload_state = DP_PAYLOAD_DELETE_LOCAL;
3198         return 0;
3199 }
3200
3201 static int drm_dp_destroy_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
3202                                         int id,
3203                                         struct drm_dp_payload *payload)
3204 {
3205         payload->payload_state = 0;
3206         return 0;
3207 }
3208
3209 /**
3210  * drm_dp_update_payload_part1() - Execute payload update part 1
3211  * @mgr: manager to use.
3212  *
3213  * This iterates over all proposed virtual channels, and tries to
3214  * allocate space in the link for them. For 0->slots transitions,
3215  * this step just writes the VCPI to the MST device. For slots->0
3216  * transitions, this writes the updated VCPIs and removes the
3217  * remote VC payloads.
3218  *
3219  * after calling this the driver should generate ACT and payload
3220  * packets.
3221  */
3222 int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
3223 {
3224         struct drm_dp_payload req_payload;
3225         struct drm_dp_mst_port *port;
3226         int i, j;
3227         int cur_slots = 1;
3228
3229         mutex_lock(&mgr->payload_lock);
3230         for (i = 0; i < mgr->max_payloads; i++) {
3231                 struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
3232                 struct drm_dp_payload *payload = &mgr->payloads[i];
3233                 bool put_port = false;
3234
3235                 /* solve the current payloads - compare to the hw ones
3236                    - update the hw view */
3237                 req_payload.start_slot = cur_slots;
3238                 if (vcpi) {
3239                         port = container_of(vcpi, struct drm_dp_mst_port,
3240                                             vcpi);
3241
3242                         /* Validated ports don't matter if we're releasing
3243                          * VCPI
3244                          */
3245                         if (vcpi->num_slots) {
3246                                 port = drm_dp_mst_topology_get_port_validated(
3247                                     mgr, port);
3248                                 if (!port) {
3249                                         mutex_unlock(&mgr->payload_lock);
3250                                         return -EINVAL;
3251                                 }
3252                                 put_port = true;
3253                         }
3254
3255                         req_payload.num_slots = vcpi->num_slots;
3256                         req_payload.vcpi = vcpi->vcpi;
3257                 } else {
3258                         port = NULL;
3259                         req_payload.num_slots = 0;
3260                 }
3261
3262                 payload->start_slot = req_payload.start_slot;
3263                 /* work out what is required to happen with this payload */
3264                 if (payload->num_slots != req_payload.num_slots) {
3265
3266                         /* need to push an update for this payload */
3267                         if (req_payload.num_slots) {
3268                                 drm_dp_create_payload_step1(mgr, vcpi->vcpi,
3269                                                             &req_payload);
3270                                 payload->num_slots = req_payload.num_slots;
3271                                 payload->vcpi = req_payload.vcpi;
3272
3273                         } else if (payload->num_slots) {
3274                                 payload->num_slots = 0;
3275                                 drm_dp_destroy_payload_step1(mgr, port,
3276                                                              payload->vcpi,
3277                                                              payload);
3278                                 req_payload.payload_state =
3279                                         payload->payload_state;
3280                                 payload->start_slot = 0;
3281                         }
3282                         payload->payload_state = req_payload.payload_state;
3283                 }
3284                 cur_slots += req_payload.num_slots;
3285
3286                 if (put_port)
3287                         drm_dp_mst_topology_put_port(port);
3288         }
3289
3290         for (i = 0; i < mgr->max_payloads; /* do nothing */) {
3291                 if (mgr->payloads[i].payload_state != DP_PAYLOAD_DELETE_LOCAL) {
3292                         i++;
3293                         continue;
3294                 }
3295
3296                 DRM_DEBUG_KMS("removing payload %d\n", i);
3297                 for (j = i; j < mgr->max_payloads - 1; j++) {
3298                         mgr->payloads[j] = mgr->payloads[j + 1];
3299                         mgr->proposed_vcpis[j] = mgr->proposed_vcpis[j + 1];
3300
3301                         if (mgr->proposed_vcpis[j] &&
3302                             mgr->proposed_vcpis[j]->num_slots) {
3303                                 set_bit(j + 1, &mgr->payload_mask);
3304                         } else {
3305                                 clear_bit(j + 1, &mgr->payload_mask);
3306                         }
3307                 }
3308
3309                 memset(&mgr->payloads[mgr->max_payloads - 1], 0,
3310                        sizeof(struct drm_dp_payload));
3311                 mgr->proposed_vcpis[mgr->max_payloads - 1] = NULL;
3312                 clear_bit(mgr->max_payloads, &mgr->payload_mask);
3313         }
3314         mutex_unlock(&mgr->payload_lock);
3315
3316         return 0;
3317 }
3318 EXPORT_SYMBOL(drm_dp_update_payload_part1);
3319
3320 /**
3321  * drm_dp_update_payload_part2() - Execute payload update part 2
3322  * @mgr: manager to use.
3323  *
3324  * This iterates over all proposed virtual channels, and tries to
3325  * allocate space in the link for them. For 0->slots transitions,
3326  * this step writes the remote VC payload commands. For slots->0
3327  * this just resets some internal state.
3328  */
3329 int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
3330 {
3331         struct drm_dp_mst_port *port;
3332         int i;
3333         int ret = 0;
3334
3335         mutex_lock(&mgr->payload_lock);
3336         for (i = 0; i < mgr->max_payloads; i++) {
3337
3338                 if (!mgr->proposed_vcpis[i])
3339                         continue;
3340
3341                 port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
3342
3343                 DRM_DEBUG_KMS("payload %d %d\n", i, mgr->payloads[i].payload_state);
3344                 if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL) {
3345                         ret = drm_dp_create_payload_step2(mgr, port, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
3346                 } else if (mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) {
3347                         ret = drm_dp_destroy_payload_step2(mgr, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
3348                 }
3349                 if (ret) {
3350                         mutex_unlock(&mgr->payload_lock);
3351                         return ret;
3352                 }
3353         }
3354         mutex_unlock(&mgr->payload_lock);
3355         return 0;
3356 }
3357 EXPORT_SYMBOL(drm_dp_update_payload_part2);
3358
3359 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
3360                                  struct drm_dp_mst_port *port,
3361                                  int offset, int size, u8 *bytes)
3362 {
3363         int ret = 0;
3364         struct drm_dp_sideband_msg_tx *txmsg;
3365         struct drm_dp_mst_branch *mstb;
3366
3367         mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3368         if (!mstb)
3369                 return -EINVAL;
3370
3371         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3372         if (!txmsg) {
3373                 ret = -ENOMEM;
3374                 goto fail_put;
3375         }
3376
3377         build_dpcd_read(txmsg, port->port_num, offset, size);
3378         txmsg->dst = port->parent;
3379
3380         drm_dp_queue_down_tx(mgr, txmsg);
3381
3382         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3383         if (ret < 0)
3384                 goto fail_free;
3385
3386         /* DPCD read should never be NACKed */
3387         if (txmsg->reply.reply_type == 1) {
3388                 DRM_ERROR("mstb %p port %d: DPCD read on addr 0x%x for %d bytes NAKed\n",
3389                           mstb, port->port_num, offset, size);
3390                 ret = -EIO;
3391                 goto fail_free;
3392         }
3393
3394         if (txmsg->reply.u.remote_dpcd_read_ack.num_bytes != size) {
3395                 ret = -EPROTO;
3396                 goto fail_free;
3397         }
3398
3399         ret = min_t(size_t, txmsg->reply.u.remote_dpcd_read_ack.num_bytes,
3400                     size);
3401         memcpy(bytes, txmsg->reply.u.remote_dpcd_read_ack.bytes, ret);
3402
3403 fail_free:
3404         kfree(txmsg);
3405 fail_put:
3406         drm_dp_mst_topology_put_mstb(mstb);
3407
3408         return ret;
3409 }
3410
3411 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
3412                                   struct drm_dp_mst_port *port,
3413                                   int offset, int size, u8 *bytes)
3414 {
3415         int ret;
3416         struct drm_dp_sideband_msg_tx *txmsg;
3417         struct drm_dp_mst_branch *mstb;
3418
3419         mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3420         if (!mstb)
3421                 return -EINVAL;
3422
3423         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3424         if (!txmsg) {
3425                 ret = -ENOMEM;
3426                 goto fail_put;
3427         }
3428
3429         build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
3430         txmsg->dst = mstb;
3431
3432         drm_dp_queue_down_tx(mgr, txmsg);
3433
3434         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3435         if (ret > 0) {
3436                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3437                         ret = -EIO;
3438                 else
3439                         ret = size;
3440         }
3441
3442         kfree(txmsg);
3443 fail_put:
3444         drm_dp_mst_topology_put_mstb(mstb);
3445         return ret;
3446 }
3447
3448 static int drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx *msg, u8 req_type)
3449 {
3450         struct drm_dp_sideband_msg_reply_body reply;
3451
3452         reply.reply_type = DP_SIDEBAND_REPLY_ACK;
3453         reply.req_type = req_type;
3454         drm_dp_encode_sideband_reply(&reply, msg);
3455         return 0;
3456 }
3457
3458 static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
3459                                     struct drm_dp_mst_branch *mstb,
3460                                     int req_type, bool broadcast)
3461 {
3462         struct drm_dp_sideband_msg_tx *txmsg;
3463
3464         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3465         if (!txmsg)
3466                 return -ENOMEM;
3467
3468         txmsg->dst = mstb;
3469         drm_dp_encode_up_ack_reply(txmsg, req_type);
3470
3471         mutex_lock(&mgr->qlock);
3472         /* construct a chunk from the first msg in the tx_msg queue */
3473         process_single_tx_qlock(mgr, txmsg, true);
3474         mutex_unlock(&mgr->qlock);
3475
3476         kfree(txmsg);
3477         return 0;
3478 }
3479
3480 static int drm_dp_get_vc_payload_bw(u8 dp_link_bw, u8  dp_link_count)
3481 {
3482         if (dp_link_bw == 0 || dp_link_count == 0)
3483                 DRM_DEBUG_KMS("invalid link bandwidth in DPCD: %x (link count: %d)\n",
3484                               dp_link_bw, dp_link_count);
3485
3486         return dp_link_bw * dp_link_count / 2;
3487 }
3488
3489 /**
3490  * drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a topology manager
3491  * @mgr: manager to set state for
3492  * @mst_state: true to enable MST on this connector - false to disable.
3493  *
3494  * This is called by the driver when it detects an MST capable device plugged
3495  * into a DP MST capable port, or when a DP MST capable device is unplugged.
3496  */
3497 int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state)
3498 {
3499         int ret = 0;
3500         struct drm_dp_mst_branch *mstb = NULL;
3501
3502         mutex_lock(&mgr->payload_lock);
3503         mutex_lock(&mgr->lock);
3504         if (mst_state == mgr->mst_state)
3505                 goto out_unlock;
3506
3507         mgr->mst_state = mst_state;
3508         /* set the device into MST mode */
3509         if (mst_state) {
3510                 struct drm_dp_payload reset_pay;
3511
3512                 WARN_ON(mgr->mst_primary);
3513
3514                 /* get dpcd info */
3515                 ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd, DP_RECEIVER_CAP_SIZE);
3516                 if (ret != DP_RECEIVER_CAP_SIZE) {
3517                         DRM_DEBUG_KMS("failed to read DPCD\n");
3518                         goto out_unlock;
3519                 }
3520
3521                 mgr->pbn_div = drm_dp_get_vc_payload_bw(mgr->dpcd[1],
3522                                                         mgr->dpcd[2] & DP_MAX_LANE_COUNT_MASK);
3523                 if (mgr->pbn_div == 0) {
3524                         ret = -EINVAL;
3525                         goto out_unlock;
3526                 }
3527
3528                 /* add initial branch device at LCT 1 */
3529                 mstb = drm_dp_add_mst_branch_device(1, NULL);
3530                 if (mstb == NULL) {
3531                         ret = -ENOMEM;
3532                         goto out_unlock;
3533                 }
3534                 mstb->mgr = mgr;
3535
3536                 /* give this the main reference */
3537                 mgr->mst_primary = mstb;
3538                 drm_dp_mst_topology_get_mstb(mgr->mst_primary);
3539
3540                 ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3541                                          DP_MST_EN |
3542                                          DP_UP_REQ_EN |
3543                                          DP_UPSTREAM_IS_SRC);
3544                 if (ret < 0)
3545                         goto out_unlock;
3546
3547                 reset_pay.start_slot = 0;
3548                 reset_pay.num_slots = 0x3f;
3549                 drm_dp_dpcd_write_payload(mgr, 0, &reset_pay);
3550
3551                 queue_work(system_long_wq, &mgr->work);
3552
3553                 ret = 0;
3554         } else {
3555                 /* disable MST on the device */
3556                 mstb = mgr->mst_primary;
3557                 mgr->mst_primary = NULL;
3558                 /* this can fail if the device is gone */
3559                 drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
3560                 ret = 0;
3561                 memset(mgr->payloads, 0,
3562                        mgr->max_payloads * sizeof(mgr->payloads[0]));
3563                 memset(mgr->proposed_vcpis, 0,
3564                        mgr->max_payloads * sizeof(mgr->proposed_vcpis[0]));
3565                 mgr->payload_mask = 0;
3566                 set_bit(0, &mgr->payload_mask);
3567                 mgr->vcpi_mask = 0;
3568                 mgr->payload_id_table_cleared = false;
3569         }
3570
3571 out_unlock:
3572         mutex_unlock(&mgr->lock);
3573         mutex_unlock(&mgr->payload_lock);
3574         if (mstb)
3575                 drm_dp_mst_topology_put_mstb(mstb);
3576         return ret;
3577
3578 }
3579 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_set_mst);
3580
3581 static void
3582 drm_dp_mst_topology_mgr_invalidate_mstb(struct drm_dp_mst_branch *mstb)
3583 {
3584         struct drm_dp_mst_port *port;
3585
3586         /* The link address will need to be re-sent on resume */
3587         mstb->link_address_sent = false;
3588
3589         list_for_each_entry(port, &mstb->ports, next)
3590                 if (port->mstb)
3591                         drm_dp_mst_topology_mgr_invalidate_mstb(port->mstb);
3592 }
3593
3594 /**
3595  * drm_dp_mst_topology_mgr_suspend() - suspend the MST manager
3596  * @mgr: manager to suspend
3597  *
3598  * This function tells the MST device that we can't handle UP messages
3599  * anymore. This should stop it from sending any since we are suspended.
3600  */
3601 void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr)
3602 {
3603         mutex_lock(&mgr->lock);
3604         drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3605                            DP_MST_EN | DP_UPSTREAM_IS_SRC);
3606         mutex_unlock(&mgr->lock);
3607         flush_work(&mgr->up_req_work);
3608         flush_work(&mgr->work);
3609         flush_work(&mgr->delayed_destroy_work);
3610
3611         mutex_lock(&mgr->lock);
3612         if (mgr->mst_state && mgr->mst_primary)
3613                 drm_dp_mst_topology_mgr_invalidate_mstb(mgr->mst_primary);
3614         mutex_unlock(&mgr->lock);
3615 }
3616 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_suspend);
3617
3618 /**
3619  * drm_dp_mst_topology_mgr_resume() - resume the MST manager
3620  * @mgr: manager to resume
3621  * @sync: whether or not to perform topology reprobing synchronously
3622  *
3623  * This will fetch DPCD and see if the device is still there,
3624  * if it is, it will rewrite the MSTM control bits, and return.
3625  *
3626  * If the device fails this returns -1, and the driver should do
3627  * a full MST reprobe, in case we were undocked.
3628  *
3629  * During system resume (where it is assumed that the driver will be calling
3630  * drm_atomic_helper_resume()) this function should be called beforehand with
3631  * @sync set to true. In contexts like runtime resume where the driver is not
3632  * expected to be calling drm_atomic_helper_resume(), this function should be
3633  * called with @sync set to false in order to avoid deadlocking.
3634  *
3635  * Returns: -1 if the MST topology was removed while we were suspended, 0
3636  * otherwise.
3637  */
3638 int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr,
3639                                    bool sync)
3640 {
3641         int ret;
3642         u8 guid[16];
3643
3644         mutex_lock(&mgr->lock);
3645         if (!mgr->mst_primary)
3646                 goto out_fail;
3647
3648         ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd,
3649                                DP_RECEIVER_CAP_SIZE);
3650         if (ret != DP_RECEIVER_CAP_SIZE) {
3651                 DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
3652                 goto out_fail;
3653         }
3654
3655         ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3656                                  DP_MST_EN |
3657                                  DP_UP_REQ_EN |
3658                                  DP_UPSTREAM_IS_SRC);
3659         if (ret < 0) {
3660                 DRM_DEBUG_KMS("mst write failed - undocked during suspend?\n");
3661                 goto out_fail;
3662         }
3663
3664         /* Some hubs forget their guids after they resume */
3665         ret = drm_dp_dpcd_read(mgr->aux, DP_GUID, guid, 16);
3666         if (ret != 16) {
3667                 DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
3668                 goto out_fail;
3669         }
3670
3671         ret = drm_dp_check_mstb_guid(mgr->mst_primary, guid);
3672         if (ret) {
3673                 DRM_DEBUG_KMS("check mstb failed - undocked during suspend?\n");
3674                 goto out_fail;
3675         }
3676
3677         /*
3678          * For the final step of resuming the topology, we need to bring the
3679          * state of our in-memory topology back into sync with reality. So,
3680          * restart the probing process as if we're probing a new hub
3681          */
3682         queue_work(system_long_wq, &mgr->work);
3683         mutex_unlock(&mgr->lock);
3684
3685         if (sync) {
3686                 DRM_DEBUG_KMS("Waiting for link probe work to finish re-syncing topology...\n");
3687                 flush_work(&mgr->work);
3688         }
3689
3690         return 0;
3691
3692 out_fail:
3693         mutex_unlock(&mgr->lock);
3694         return -1;
3695 }
3696 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume);
3697
3698 static bool
3699 drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up,
3700                       struct drm_dp_mst_branch **mstb)
3701 {
3702         int len;
3703         u8 replyblock[32];
3704         int replylen, curreply;
3705         int ret;
3706         u8 hdrlen;
3707         struct drm_dp_sideband_msg_hdr hdr;
3708         struct drm_dp_sideband_msg_rx *msg =
3709                 up ? &mgr->up_req_recv : &mgr->down_rep_recv;
3710         int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE :
3711                            DP_SIDEBAND_MSG_DOWN_REP_BASE;
3712
3713         if (!up)
3714                 *mstb = NULL;
3715
3716         len = min(mgr->max_dpcd_transaction_bytes, 16);
3717         ret = drm_dp_dpcd_read(mgr->aux, basereg, replyblock, len);
3718         if (ret != len) {
3719                 DRM_DEBUG_KMS("failed to read DPCD down rep %d %d\n", len, ret);
3720                 return false;
3721         }
3722
3723         ret = drm_dp_decode_sideband_msg_hdr(&hdr, replyblock, len, &hdrlen);
3724         if (ret == false) {
3725                 print_hex_dump(KERN_DEBUG, "failed hdr", DUMP_PREFIX_NONE, 16,
3726                                1, replyblock, len, false);
3727                 DRM_DEBUG_KMS("ERROR: failed header\n");
3728                 return false;
3729         }
3730
3731         if (!up) {
3732                 /* Caller is responsible for giving back this reference */
3733                 *mstb = drm_dp_get_mst_branch_device(mgr, hdr.lct, hdr.rad);
3734                 if (!*mstb) {
3735                         DRM_DEBUG_KMS("Got MST reply from unknown device %d\n",
3736                                       hdr.lct);
3737                         return false;
3738                 }
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 = &mgr->down_rep_recv;
3783
3784         if (!drm_dp_get_one_sb_msg(mgr, false, &mstb))
3785                 goto out;
3786
3787         /* Multi-packet message transmission, don't clear the reply */
3788         if (!msg->have_eomt)
3789                 goto out;
3790
3791         /* find the message */
3792         mutex_lock(&mgr->qlock);
3793         txmsg = list_first_entry_or_null(&mgr->tx_msg_downq,
3794                                          struct drm_dp_sideband_msg_tx, next);
3795         mutex_unlock(&mgr->qlock);
3796
3797         /* Were we actually expecting a response, and from this mstb? */
3798         if (!txmsg || txmsg->dst != mstb) {
3799                 struct drm_dp_sideband_msg_hdr *hdr;
3800
3801                 hdr = &msg->initial_hdr;
3802                 DRM_DEBUG_KMS("Got MST reply with no msg %p %d %d %02x %02x\n",
3803                               mstb, hdr->seqno, hdr->lct, hdr->rad[0],
3804                               msg->msg[0]);
3805                 goto out_clear_reply;
3806         }
3807
3808         drm_dp_sideband_parse_reply(msg, &txmsg->reply);
3809
3810         if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3811                 DRM_DEBUG_KMS("Got NAK reply: req 0x%02x (%s), reason 0x%02x (%s), nak data 0x%02x\n",
3812                               txmsg->reply.req_type,
3813                               drm_dp_mst_req_type_str(txmsg->reply.req_type),
3814                               txmsg->reply.u.nak.reason,
3815                               drm_dp_mst_nak_reason_str(txmsg->reply.u.nak.reason),
3816                               txmsg->reply.u.nak.nak_data);
3817         }
3818
3819         memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
3820         drm_dp_mst_topology_put_mstb(mstb);
3821
3822         mutex_lock(&mgr->qlock);
3823         txmsg->state = DRM_DP_SIDEBAND_TX_RX;
3824         list_del(&txmsg->next);
3825         mutex_unlock(&mgr->qlock);
3826
3827         wake_up_all(&mgr->tx_waitq);
3828
3829         return 0;
3830
3831 out_clear_reply:
3832         memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
3833 out:
3834         if (mstb)
3835                 drm_dp_mst_topology_put_mstb(mstb);
3836
3837         return 0;
3838 }
3839
3840 static inline bool
3841 drm_dp_mst_process_up_req(struct drm_dp_mst_topology_mgr *mgr,
3842                           struct drm_dp_pending_up_req *up_req)
3843 {
3844         struct drm_dp_mst_branch *mstb = NULL;
3845         struct drm_dp_sideband_msg_req_body *msg = &up_req->msg;
3846         struct drm_dp_sideband_msg_hdr *hdr = &up_req->hdr;
3847         bool hotplug = false;
3848
3849         if (hdr->broadcast) {
3850                 const u8 *guid = NULL;
3851
3852                 if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY)
3853                         guid = msg->u.conn_stat.guid;
3854                 else if (msg->req_type == DP_RESOURCE_STATUS_NOTIFY)
3855                         guid = msg->u.resource_stat.guid;
3856
3857                 if (guid)
3858                         mstb = drm_dp_get_mst_branch_device_by_guid(mgr, guid);
3859         } else {
3860                 mstb = drm_dp_get_mst_branch_device(mgr, hdr->lct, hdr->rad);
3861         }
3862
3863         if (!mstb) {
3864                 DRM_DEBUG_KMS("Got MST reply from unknown device %d\n",
3865                               hdr->lct);
3866                 return false;
3867         }
3868
3869         /* TODO: Add missing handler for DP_RESOURCE_STATUS_NOTIFY events */
3870         if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY) {
3871                 drm_dp_mst_handle_conn_stat(mstb, &msg->u.conn_stat);
3872                 hotplug = true;
3873         }
3874
3875         drm_dp_mst_topology_put_mstb(mstb);
3876         return hotplug;
3877 }
3878
3879 static void drm_dp_mst_up_req_work(struct work_struct *work)
3880 {
3881         struct drm_dp_mst_topology_mgr *mgr =
3882                 container_of(work, struct drm_dp_mst_topology_mgr,
3883                              up_req_work);
3884         struct drm_dp_pending_up_req *up_req;
3885         bool send_hotplug = false;
3886
3887         mutex_lock(&mgr->probe_lock);
3888         while (true) {
3889                 mutex_lock(&mgr->up_req_lock);
3890                 up_req = list_first_entry_or_null(&mgr->up_req_list,
3891                                                   struct drm_dp_pending_up_req,
3892                                                   next);
3893                 if (up_req)
3894                         list_del(&up_req->next);
3895                 mutex_unlock(&mgr->up_req_lock);
3896
3897                 if (!up_req)
3898                         break;
3899
3900                 send_hotplug |= drm_dp_mst_process_up_req(mgr, up_req);
3901                 kfree(up_req);
3902         }
3903         mutex_unlock(&mgr->probe_lock);
3904
3905         if (send_hotplug)
3906                 drm_kms_helper_hotplug_event(mgr->dev);
3907 }
3908
3909 static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
3910 {
3911         struct drm_dp_pending_up_req *up_req;
3912
3913         if (!drm_dp_get_one_sb_msg(mgr, true, NULL))
3914                 goto out;
3915
3916         if (!mgr->up_req_recv.have_eomt)
3917                 return 0;
3918
3919         up_req = kzalloc(sizeof(*up_req), GFP_KERNEL);
3920         if (!up_req) {
3921                 DRM_ERROR("Not enough memory to process MST up req\n");
3922                 return -ENOMEM;
3923         }
3924         INIT_LIST_HEAD(&up_req->next);
3925
3926         drm_dp_sideband_parse_req(&mgr->up_req_recv, &up_req->msg);
3927
3928         if (up_req->msg.req_type != DP_CONNECTION_STATUS_NOTIFY &&
3929             up_req->msg.req_type != DP_RESOURCE_STATUS_NOTIFY) {
3930                 DRM_DEBUG_KMS("Received unknown up req type, ignoring: %x\n",
3931                               up_req->msg.req_type);
3932                 kfree(up_req);
3933                 goto out;
3934         }
3935
3936         drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, up_req->msg.req_type,
3937                                  false);
3938
3939         if (up_req->msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
3940                 const struct drm_dp_connection_status_notify *conn_stat =
3941                         &up_req->msg.u.conn_stat;
3942
3943                 DRM_DEBUG_KMS("Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n",
3944                               conn_stat->port_number,
3945                               conn_stat->legacy_device_plug_status,
3946                               conn_stat->displayport_device_plug_status,
3947                               conn_stat->message_capability_status,
3948                               conn_stat->input_port,
3949                               conn_stat->peer_device_type);
3950         } else if (up_req->msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
3951                 const struct drm_dp_resource_status_notify *res_stat =
3952                         &up_req->msg.u.resource_stat;
3953
3954                 DRM_DEBUG_KMS("Got RSN: pn: %d avail_pbn %d\n",
3955                               res_stat->port_number,
3956                               res_stat->available_pbn);
3957         }
3958
3959         up_req->hdr = mgr->up_req_recv.initial_hdr;
3960         mutex_lock(&mgr->up_req_lock);
3961         list_add_tail(&up_req->next, &mgr->up_req_list);
3962         mutex_unlock(&mgr->up_req_lock);
3963         queue_work(system_long_wq, &mgr->up_req_work);
3964
3965 out:
3966         memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
3967         return 0;
3968 }
3969
3970 /**
3971  * drm_dp_mst_hpd_irq() - MST hotplug IRQ notify
3972  * @mgr: manager to notify irq for.
3973  * @esi: 4 bytes from SINK_COUNT_ESI
3974  * @handled: whether the hpd interrupt was consumed or not
3975  *
3976  * This should be called from the driver when it detects a short IRQ,
3977  * along with the value of the DEVICE_SERVICE_IRQ_VECTOR_ESI0. The
3978  * topology manager will process the sideband messages received as a result
3979  * of this.
3980  */
3981 int drm_dp_mst_hpd_irq(struct drm_dp_mst_topology_mgr *mgr, u8 *esi, bool *handled)
3982 {
3983         int ret = 0;
3984         int sc;
3985         *handled = false;
3986         sc = esi[0] & 0x3f;
3987
3988         if (sc != mgr->sink_count) {
3989                 mgr->sink_count = sc;
3990                 *handled = true;
3991         }
3992
3993         if (esi[1] & DP_DOWN_REP_MSG_RDY) {
3994                 ret = drm_dp_mst_handle_down_rep(mgr);
3995                 *handled = true;
3996         }
3997
3998         if (esi[1] & DP_UP_REQ_MSG_RDY) {
3999                 ret |= drm_dp_mst_handle_up_req(mgr);
4000                 *handled = true;
4001         }
4002
4003         drm_dp_mst_kick_tx(mgr);
4004         return ret;
4005 }
4006 EXPORT_SYMBOL(drm_dp_mst_hpd_irq);
4007
4008 /**
4009  * drm_dp_mst_detect_port() - get connection status for an MST port
4010  * @connector: DRM connector for this port
4011  * @ctx: The acquisition context to use for grabbing locks
4012  * @mgr: manager for this port
4013  * @port: pointer to a port
4014  *
4015  * This returns the current connection state for a port.
4016  */
4017 int
4018 drm_dp_mst_detect_port(struct drm_connector *connector,
4019                        struct drm_modeset_acquire_ctx *ctx,
4020                        struct drm_dp_mst_topology_mgr *mgr,
4021                        struct drm_dp_mst_port *port)
4022 {
4023         int ret;
4024
4025         /* we need to search for the port in the mgr in case it's gone */
4026         port = drm_dp_mst_topology_get_port_validated(mgr, port);
4027         if (!port)
4028                 return connector_status_disconnected;
4029
4030         ret = drm_modeset_lock(&mgr->base.lock, ctx);
4031         if (ret)
4032                 goto out;
4033
4034         ret = connector_status_disconnected;
4035
4036         if (!port->ddps)
4037                 goto out;
4038
4039         switch (port->pdt) {
4040         case DP_PEER_DEVICE_NONE:
4041         case DP_PEER_DEVICE_MST_BRANCHING:
4042                 if (!port->mcs)
4043                         ret = connector_status_connected;
4044                 break;
4045
4046         case DP_PEER_DEVICE_SST_SINK:
4047                 ret = connector_status_connected;
4048                 /* for logical ports - cache the EDID */
4049                 if (port->port_num >= 8 && !port->cached_edid) {
4050                         port->cached_edid = drm_get_edid(connector, &port->aux.ddc);
4051                 }
4052                 break;
4053         case DP_PEER_DEVICE_DP_LEGACY_CONV:
4054                 if (port->ldps)
4055                         ret = connector_status_connected;
4056                 break;
4057         }
4058 out:
4059         drm_dp_mst_topology_put_port(port);
4060         return ret;
4061 }
4062 EXPORT_SYMBOL(drm_dp_mst_detect_port);
4063
4064 /**
4065  * drm_dp_mst_get_edid() - get EDID for an MST port
4066  * @connector: toplevel connector to get EDID for
4067  * @mgr: manager for this port
4068  * @port: unverified pointer to a port.
4069  *
4070  * This returns an EDID for the port connected to a connector,
4071  * It validates the pointer still exists so the caller doesn't require a
4072  * reference.
4073  */
4074 struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4075 {
4076         struct edid *edid = NULL;
4077
4078         /* we need to search for the port in the mgr in case it's gone */
4079         port = drm_dp_mst_topology_get_port_validated(mgr, port);
4080         if (!port)
4081                 return NULL;
4082
4083         if (port->cached_edid)
4084                 edid = drm_edid_duplicate(port->cached_edid);
4085         else {
4086                 edid = drm_get_edid(connector, &port->aux.ddc);
4087         }
4088         port->has_audio = drm_detect_monitor_audio(edid);
4089         drm_dp_mst_topology_put_port(port);
4090         return edid;
4091 }
4092 EXPORT_SYMBOL(drm_dp_mst_get_edid);
4093
4094 /**
4095  * drm_dp_find_vcpi_slots() - Find VCPI slots for this PBN value
4096  * @mgr: manager to use
4097  * @pbn: payload bandwidth to convert into slots.
4098  *
4099  * Calculate the number of VCPI slots that will be required for the given PBN
4100  * value. This function is deprecated, and should not be used in atomic
4101  * drivers.
4102  *
4103  * RETURNS:
4104  * The total slots required for this port, or error.
4105  */
4106 int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
4107                            int pbn)
4108 {
4109         int num_slots;
4110
4111         num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
4112
4113         /* max. time slots - one slot for MTP header */
4114         if (num_slots > 63)
4115                 return -ENOSPC;
4116         return num_slots;
4117 }
4118 EXPORT_SYMBOL(drm_dp_find_vcpi_slots);
4119
4120 static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
4121                             struct drm_dp_vcpi *vcpi, int pbn, int slots)
4122 {
4123         int ret;
4124
4125         /* max. time slots - one slot for MTP header */
4126         if (slots > 63)
4127                 return -ENOSPC;
4128
4129         vcpi->pbn = pbn;
4130         vcpi->aligned_pbn = slots * mgr->pbn_div;
4131         vcpi->num_slots = slots;
4132
4133         ret = drm_dp_mst_assign_payload_id(mgr, vcpi);
4134         if (ret < 0)
4135                 return ret;
4136         return 0;
4137 }
4138
4139 /**
4140  * drm_dp_atomic_find_vcpi_slots() - Find and add VCPI slots to the state
4141  * @state: global atomic state
4142  * @mgr: MST topology manager for the port
4143  * @port: port to find vcpi slots for
4144  * @pbn: bandwidth required for the mode in PBN
4145  * @pbn_div: divider for DSC mode that takes FEC into account
4146  *
4147  * Allocates VCPI slots to @port, replacing any previous VCPI allocations it
4148  * may have had. Any atomic drivers which support MST must call this function
4149  * in their &drm_encoder_helper_funcs.atomic_check() callback to change the
4150  * current VCPI allocation for the new state, but only when
4151  * &drm_crtc_state.mode_changed or &drm_crtc_state.connectors_changed is set
4152  * to ensure compatibility with userspace applications that still use the
4153  * legacy modesetting UAPI.
4154  *
4155  * Allocations set by this function are not checked against the bandwidth
4156  * restraints of @mgr until the driver calls drm_dp_mst_atomic_check().
4157  *
4158  * Additionally, it is OK to call this function multiple times on the same
4159  * @port as needed. It is not OK however, to call this function and
4160  * drm_dp_atomic_release_vcpi_slots() in the same atomic check phase.
4161  *
4162  * See also:
4163  * drm_dp_atomic_release_vcpi_slots()
4164  * drm_dp_mst_atomic_check()
4165  *
4166  * Returns:
4167  * Total slots in the atomic state assigned for this port, or a negative error
4168  * code if the port no longer exists
4169  */
4170 int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
4171                                   struct drm_dp_mst_topology_mgr *mgr,
4172                                   struct drm_dp_mst_port *port, int pbn,
4173                                   int pbn_div)
4174 {
4175         struct drm_dp_mst_topology_state *topology_state;
4176         struct drm_dp_vcpi_allocation *pos, *vcpi = NULL;
4177         int prev_slots, prev_bw, req_slots;
4178
4179         topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4180         if (IS_ERR(topology_state))
4181                 return PTR_ERR(topology_state);
4182
4183         /* Find the current allocation for this port, if any */
4184         list_for_each_entry(pos, &topology_state->vcpis, next) {
4185                 if (pos->port == port) {
4186                         vcpi = pos;
4187                         prev_slots = vcpi->vcpi;
4188                         prev_bw = vcpi->pbn;
4189
4190                         /*
4191                          * This should never happen, unless the driver tries
4192                          * releasing and allocating the same VCPI allocation,
4193                          * which is an error
4194                          */
4195                         if (WARN_ON(!prev_slots)) {
4196                                 DRM_ERROR("cannot allocate and release VCPI on [MST PORT:%p] in the same state\n",
4197                                           port);
4198                                 return -EINVAL;
4199                         }
4200
4201                         break;
4202                 }
4203         }
4204         if (!vcpi) {
4205                 prev_slots = 0;
4206                 prev_bw = 0;
4207         }
4208
4209         if (pbn_div <= 0)
4210                 pbn_div = mgr->pbn_div;
4211
4212         req_slots = DIV_ROUND_UP(pbn, pbn_div);
4213
4214         DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] [MST PORT:%p] VCPI %d -> %d\n",
4215                          port->connector->base.id, port->connector->name,
4216                          port, prev_slots, req_slots);
4217         DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] [MST PORT:%p] PBN %d -> %d\n",
4218                          port->connector->base.id, port->connector->name,
4219                          port, prev_bw, pbn);
4220
4221         /* Add the new allocation to the state */
4222         if (!vcpi) {
4223                 vcpi = kzalloc(sizeof(*vcpi), GFP_KERNEL);
4224                 if (!vcpi)
4225                         return -ENOMEM;
4226
4227                 drm_dp_mst_get_port_malloc(port);
4228                 vcpi->port = port;
4229                 list_add(&vcpi->next, &topology_state->vcpis);
4230         }
4231         vcpi->vcpi = req_slots;
4232         vcpi->pbn = pbn;
4233
4234         return req_slots;
4235 }
4236 EXPORT_SYMBOL(drm_dp_atomic_find_vcpi_slots);
4237
4238 /**
4239  * drm_dp_atomic_release_vcpi_slots() - Release allocated vcpi slots
4240  * @state: global atomic state
4241  * @mgr: MST topology manager for the port
4242  * @port: The port to release the VCPI slots from
4243  *
4244  * Releases any VCPI slots that have been allocated to a port in the atomic
4245  * state. Any atomic drivers which support MST must call this function in
4246  * their &drm_connector_helper_funcs.atomic_check() callback when the
4247  * connector will no longer have VCPI allocated (e.g. because its CRTC was
4248  * removed) when it had VCPI allocated in the previous atomic state.
4249  *
4250  * It is OK to call this even if @port has been removed from the system.
4251  * Additionally, it is OK to call this function multiple times on the same
4252  * @port as needed. It is not OK however, to call this function and
4253  * drm_dp_atomic_find_vcpi_slots() on the same @port in a single atomic check
4254  * phase.
4255  *
4256  * See also:
4257  * drm_dp_atomic_find_vcpi_slots()
4258  * drm_dp_mst_atomic_check()
4259  *
4260  * Returns:
4261  * 0 if all slots for this port were added back to
4262  * &drm_dp_mst_topology_state.avail_slots or negative error code
4263  */
4264 int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
4265                                      struct drm_dp_mst_topology_mgr *mgr,
4266                                      struct drm_dp_mst_port *port)
4267 {
4268         struct drm_dp_mst_topology_state *topology_state;
4269         struct drm_dp_vcpi_allocation *pos;
4270         bool found = false;
4271
4272         topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4273         if (IS_ERR(topology_state))
4274                 return PTR_ERR(topology_state);
4275
4276         list_for_each_entry(pos, &topology_state->vcpis, next) {
4277                 if (pos->port == port) {
4278                         found = true;
4279                         break;
4280                 }
4281         }
4282         if (WARN_ON(!found)) {
4283                 DRM_ERROR("no VCPI for [MST PORT:%p] found in mst state %p\n",
4284                           port, &topology_state->base);
4285                 return -EINVAL;
4286         }
4287
4288         DRM_DEBUG_ATOMIC("[MST PORT:%p] VCPI %d -> 0\n", port, pos->vcpi);
4289         if (pos->vcpi) {
4290                 drm_dp_mst_put_port_malloc(port);
4291                 pos->vcpi = 0;
4292                 pos->pbn = 0;
4293         }
4294
4295         return 0;
4296 }
4297 EXPORT_SYMBOL(drm_dp_atomic_release_vcpi_slots);
4298
4299 /**
4300  * drm_dp_mst_allocate_vcpi() - Allocate a virtual channel
4301  * @mgr: manager for this port
4302  * @port: port to allocate a virtual channel for.
4303  * @pbn: payload bandwidth number to request
4304  * @slots: returned number of slots for this PBN.
4305  */
4306 bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
4307                               struct drm_dp_mst_port *port, int pbn, int slots)
4308 {
4309         int ret;
4310
4311         if (slots < 0)
4312                 return false;
4313
4314         port = drm_dp_mst_topology_get_port_validated(mgr, port);
4315         if (!port)
4316                 return false;
4317
4318         if (port->vcpi.vcpi > 0) {
4319                 DRM_DEBUG_KMS("payload: vcpi %d already allocated for pbn %d - requested pbn %d\n",
4320                               port->vcpi.vcpi, port->vcpi.pbn, pbn);
4321                 if (pbn == port->vcpi.pbn) {
4322                         drm_dp_mst_topology_put_port(port);
4323                         return true;
4324                 }
4325         }
4326
4327         ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn, slots);
4328         if (ret) {
4329                 DRM_DEBUG_KMS("failed to init vcpi slots=%d max=63 ret=%d\n",
4330                               DIV_ROUND_UP(pbn, mgr->pbn_div), ret);
4331                 drm_dp_mst_topology_put_port(port);
4332                 goto out;
4333         }
4334         DRM_DEBUG_KMS("initing vcpi for pbn=%d slots=%d\n",
4335                       pbn, port->vcpi.num_slots);
4336
4337         /* Keep port allocated until its payload has been removed */
4338         drm_dp_mst_get_port_malloc(port);
4339         drm_dp_mst_topology_put_port(port);
4340         return true;
4341 out:
4342         return false;
4343 }
4344 EXPORT_SYMBOL(drm_dp_mst_allocate_vcpi);
4345
4346 int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4347 {
4348         int slots = 0;
4349
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         drm_dp_port_set_pdt(port, DP_PEER_DEVICE_NONE, port->mcs);
4694
4695         if (port->connector) {
4696                 drm_connector_unregister(port->connector);
4697                 drm_connector_put(port->connector);
4698         }
4699
4700         drm_dp_mst_put_port_malloc(port);
4701 }
4702
4703 static inline void
4704 drm_dp_delayed_destroy_mstb(struct drm_dp_mst_branch *mstb)
4705 {
4706         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
4707         struct drm_dp_mst_port *port, *port_tmp;
4708         struct drm_dp_sideband_msg_tx *txmsg, *txmsg_tmp;
4709         bool wake_tx = false;
4710
4711         mutex_lock(&mgr->lock);
4712         list_for_each_entry_safe(port, port_tmp, &mstb->ports, next) {
4713                 list_del(&port->next);
4714                 drm_dp_mst_topology_put_port(port);
4715         }
4716         mutex_unlock(&mgr->lock);
4717
4718         /* drop any tx slot msg */
4719         mutex_lock(&mstb->mgr->qlock);
4720         list_for_each_entry_safe(txmsg, txmsg_tmp, &mgr->tx_msg_downq, next) {
4721                 if (txmsg->dst != mstb)
4722                         continue;
4723
4724                 txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
4725                 list_del(&txmsg->next);
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
5233         /*
5234          * delayed_destroy_work will be queued on a dedicated WQ, so that any
5235          * requeuing will be also flushed when deiniting the topology manager.
5236          */
5237         mgr->delayed_destroy_wq = alloc_ordered_workqueue("drm_dp_mst_wq", 0);
5238         if (mgr->delayed_destroy_wq == NULL)
5239                 return -ENOMEM;
5240
5241         INIT_WORK(&mgr->work, drm_dp_mst_link_probe_work);
5242         INIT_WORK(&mgr->tx_work, drm_dp_tx_work);
5243         INIT_WORK(&mgr->delayed_destroy_work, drm_dp_delayed_destroy_work);
5244         INIT_WORK(&mgr->up_req_work, drm_dp_mst_up_req_work);
5245         init_waitqueue_head(&mgr->tx_waitq);
5246         mgr->dev = dev;
5247         mgr->aux = aux;
5248         mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes;
5249         mgr->max_payloads = max_payloads;
5250         mgr->conn_base_id = conn_base_id;
5251         if (max_payloads + 1 > sizeof(mgr->payload_mask) * 8 ||
5252             max_payloads + 1 > sizeof(mgr->vcpi_mask) * 8)
5253                 return -EINVAL;
5254         mgr->payloads = kcalloc(max_payloads, sizeof(struct drm_dp_payload), GFP_KERNEL);
5255         if (!mgr->payloads)
5256                 return -ENOMEM;
5257         mgr->proposed_vcpis = kcalloc(max_payloads, sizeof(struct drm_dp_vcpi *), GFP_KERNEL);
5258         if (!mgr->proposed_vcpis)
5259                 return -ENOMEM;
5260         set_bit(0, &mgr->payload_mask);
5261
5262         mst_state = kzalloc(sizeof(*mst_state), GFP_KERNEL);
5263         if (mst_state == NULL)
5264                 return -ENOMEM;
5265
5266         mst_state->mgr = mgr;
5267         INIT_LIST_HEAD(&mst_state->vcpis);
5268
5269         drm_atomic_private_obj_init(dev, &mgr->base,
5270                                     &mst_state->base,
5271                                     &drm_dp_mst_topology_state_funcs);
5272
5273         return 0;
5274 }
5275 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_init);
5276
5277 /**
5278  * drm_dp_mst_topology_mgr_destroy() - destroy topology manager.
5279  * @mgr: manager to destroy
5280  */
5281 void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
5282 {
5283         drm_dp_mst_topology_mgr_set_mst(mgr, false);
5284         flush_work(&mgr->work);
5285         /* The following will also drain any requeued work on the WQ. */
5286         if (mgr->delayed_destroy_wq) {
5287                 destroy_workqueue(mgr->delayed_destroy_wq);
5288                 mgr->delayed_destroy_wq = NULL;
5289         }
5290         mutex_lock(&mgr->payload_lock);
5291         kfree(mgr->payloads);
5292         mgr->payloads = NULL;
5293         kfree(mgr->proposed_vcpis);
5294         mgr->proposed_vcpis = NULL;
5295         mutex_unlock(&mgr->payload_lock);
5296         mgr->dev = NULL;
5297         mgr->aux = NULL;
5298         drm_atomic_private_obj_fini(&mgr->base);
5299         mgr->funcs = NULL;
5300
5301         mutex_destroy(&mgr->delayed_destroy_lock);
5302         mutex_destroy(&mgr->payload_lock);
5303         mutex_destroy(&mgr->qlock);
5304         mutex_destroy(&mgr->lock);
5305         mutex_destroy(&mgr->up_req_lock);
5306         mutex_destroy(&mgr->probe_lock);
5307 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5308         mutex_destroy(&mgr->topology_ref_history_lock);
5309 #endif
5310 }
5311 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy);
5312
5313 static bool remote_i2c_read_ok(const struct i2c_msg msgs[], int num)
5314 {
5315         int i;
5316
5317         if (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS)
5318                 return false;
5319
5320         for (i = 0; i < num - 1; i++) {
5321                 if (msgs[i].flags & I2C_M_RD ||
5322                     msgs[i].len > 0xff)
5323                         return false;
5324         }
5325
5326         return msgs[num - 1].flags & I2C_M_RD &&
5327                 msgs[num - 1].len <= 0xff;
5328 }
5329
5330 /* I2C device */
5331 static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
5332                                int num)
5333 {
5334         struct drm_dp_aux *aux = adapter->algo_data;
5335         struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port, aux);
5336         struct drm_dp_mst_branch *mstb;
5337         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5338         unsigned int i;
5339         struct drm_dp_sideband_msg_req_body msg;
5340         struct drm_dp_sideband_msg_tx *txmsg = NULL;
5341         int ret;
5342
5343         mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
5344         if (!mstb)
5345                 return -EREMOTEIO;
5346
5347         if (!remote_i2c_read_ok(msgs, num)) {
5348                 DRM_DEBUG_KMS("Unsupported I2C transaction for MST device\n");
5349                 ret = -EIO;
5350                 goto out;
5351         }
5352
5353         memset(&msg, 0, sizeof(msg));
5354         msg.req_type = DP_REMOTE_I2C_READ;
5355         msg.u.i2c_read.num_transactions = num - 1;
5356         msg.u.i2c_read.port_number = port->port_num;
5357         for (i = 0; i < num - 1; i++) {
5358                 msg.u.i2c_read.transactions[i].i2c_dev_id = msgs[i].addr;
5359                 msg.u.i2c_read.transactions[i].num_bytes = msgs[i].len;
5360                 msg.u.i2c_read.transactions[i].bytes = msgs[i].buf;
5361                 msg.u.i2c_read.transactions[i].no_stop_bit = !(msgs[i].flags & I2C_M_STOP);
5362         }
5363         msg.u.i2c_read.read_i2c_device_id = msgs[num - 1].addr;
5364         msg.u.i2c_read.num_bytes_read = msgs[num - 1].len;
5365
5366         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5367         if (!txmsg) {
5368                 ret = -ENOMEM;
5369                 goto out;
5370         }
5371
5372         txmsg->dst = mstb;
5373         drm_dp_encode_sideband_req(&msg, txmsg);
5374
5375         drm_dp_queue_down_tx(mgr, txmsg);
5376
5377         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5378         if (ret > 0) {
5379
5380                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5381                         ret = -EREMOTEIO;
5382                         goto out;
5383                 }
5384                 if (txmsg->reply.u.remote_i2c_read_ack.num_bytes != msgs[num - 1].len) {
5385                         ret = -EIO;
5386                         goto out;
5387                 }
5388                 memcpy(msgs[num - 1].buf, txmsg->reply.u.remote_i2c_read_ack.bytes, msgs[num - 1].len);
5389                 ret = num;
5390         }
5391 out:
5392         kfree(txmsg);
5393         drm_dp_mst_topology_put_mstb(mstb);
5394         return ret;
5395 }
5396
5397 static u32 drm_dp_mst_i2c_functionality(struct i2c_adapter *adapter)
5398 {
5399         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
5400                I2C_FUNC_SMBUS_READ_BLOCK_DATA |
5401                I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
5402                I2C_FUNC_10BIT_ADDR;
5403 }
5404
5405 static const struct i2c_algorithm drm_dp_mst_i2c_algo = {
5406         .functionality = drm_dp_mst_i2c_functionality,
5407         .master_xfer = drm_dp_mst_i2c_xfer,
5408 };
5409
5410 /**
5411  * drm_dp_mst_register_i2c_bus() - register an I2C adapter for I2C-over-AUX
5412  * @port: The port to add the I2C bus on
5413  *
5414  * Returns 0 on success or a negative error code on failure.
5415  */
5416 static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port)
5417 {
5418         struct drm_dp_aux *aux = &port->aux;
5419         struct device *parent_dev = port->mgr->dev->dev;
5420
5421         aux->ddc.algo = &drm_dp_mst_i2c_algo;
5422         aux->ddc.algo_data = aux;
5423         aux->ddc.retries = 3;
5424
5425         aux->ddc.class = I2C_CLASS_DDC;
5426         aux->ddc.owner = THIS_MODULE;
5427         /* FIXME: set the kdev of the port's connector as parent */
5428         aux->ddc.dev.parent = parent_dev;
5429         aux->ddc.dev.of_node = parent_dev->of_node;
5430
5431         strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(parent_dev),
5432                 sizeof(aux->ddc.name));
5433
5434         return i2c_add_adapter(&aux->ddc);
5435 }
5436
5437 /**
5438  * drm_dp_mst_unregister_i2c_bus() - unregister an I2C-over-AUX adapter
5439  * @port: The port to remove the I2C bus from
5440  */
5441 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port)
5442 {
5443         i2c_del_adapter(&port->aux.ddc);
5444 }
5445
5446 /**
5447  * drm_dp_mst_is_virtual_dpcd() - Is the given port a virtual DP Peer Device
5448  * @port: The port to check
5449  *
5450  * A single physical MST hub object can be represented in the topology
5451  * by multiple branches, with virtual ports between those branches.
5452  *
5453  * As of DP1.4, An MST hub with internal (virtual) ports must expose
5454  * certain DPCD registers over those ports. See sections 2.6.1.1.1
5455  * and 2.6.1.1.2 of Display Port specification v1.4 for details.
5456  *
5457  * May acquire mgr->lock
5458  *
5459  * Returns:
5460  * true if the port is a virtual DP peer device, false otherwise
5461  */
5462 static bool drm_dp_mst_is_virtual_dpcd(struct drm_dp_mst_port *port)
5463 {
5464         struct drm_dp_mst_port *downstream_port;
5465
5466         if (!port || port->dpcd_rev < DP_DPCD_REV_14)
5467                 return false;
5468
5469         /* Virtual DP Sink (Internal Display Panel) */
5470         if (port->port_num >= 8)
5471                 return true;
5472
5473         /* DP-to-HDMI Protocol Converter */
5474         if (port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV &&
5475             !port->mcs &&
5476             port->ldps)
5477                 return true;
5478
5479         /* DP-to-DP */
5480         mutex_lock(&port->mgr->lock);
5481         if (port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
5482             port->mstb &&
5483             port->mstb->num_ports == 2) {
5484                 list_for_each_entry(downstream_port, &port->mstb->ports, next) {
5485                         if (downstream_port->pdt == DP_PEER_DEVICE_SST_SINK &&
5486                             !downstream_port->input) {
5487                                 mutex_unlock(&port->mgr->lock);
5488                                 return true;
5489                         }
5490                 }
5491         }
5492         mutex_unlock(&port->mgr->lock);
5493
5494         return false;
5495 }
5496
5497 /**
5498  * drm_dp_mst_dsc_aux_for_port() - Find the correct aux for DSC
5499  * @port: The port to check. A leaf of the MST tree with an attached display.
5500  *
5501  * Depending on the situation, DSC may be enabled via the endpoint aux,
5502  * the immediately upstream aux, or the connector's physical aux.
5503  *
5504  * This is both the correct aux to read DSC_CAPABILITY and the
5505  * correct aux to write DSC_ENABLED.
5506  *
5507  * This operation can be expensive (up to four aux reads), so
5508  * the caller should cache the return.
5509  *
5510  * Returns:
5511  * NULL if DSC cannot be enabled on this port, otherwise the aux device
5512  */
5513 struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port)
5514 {
5515         struct drm_dp_mst_port *immediate_upstream_port;
5516         struct drm_dp_mst_port *fec_port;
5517         struct drm_dp_desc desc = {};
5518         u8 endpoint_fec;
5519         u8 endpoint_dsc;
5520
5521         if (!port)
5522                 return NULL;
5523
5524         if (port->parent->port_parent)
5525                 immediate_upstream_port = port->parent->port_parent;
5526         else
5527                 immediate_upstream_port = NULL;
5528
5529         fec_port = immediate_upstream_port;
5530         while (fec_port) {
5531                 /*
5532                  * Each physical link (i.e. not a virtual port) between the
5533                  * output and the primary device must support FEC
5534                  */
5535                 if (!drm_dp_mst_is_virtual_dpcd(fec_port) &&
5536                     !fec_port->fec_capable)
5537                         return NULL;
5538
5539                 fec_port = fec_port->parent->port_parent;
5540         }
5541
5542         /* DP-to-DP peer device */
5543         if (drm_dp_mst_is_virtual_dpcd(immediate_upstream_port)) {
5544                 u8 upstream_dsc;
5545
5546                 if (drm_dp_dpcd_read(&port->aux,
5547                                      DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
5548                         return NULL;
5549                 if (drm_dp_dpcd_read(&port->aux,
5550                                      DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
5551                         return NULL;
5552                 if (drm_dp_dpcd_read(&immediate_upstream_port->aux,
5553                                      DP_DSC_SUPPORT, &upstream_dsc, 1) != 1)
5554                         return NULL;
5555
5556                 /* Enpoint decompression with DP-to-DP peer device */
5557                 if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
5558                     (endpoint_fec & DP_FEC_CAPABLE) &&
5559                     (upstream_dsc & 0x2) /* DSC passthrough */)
5560                         return &port->aux;
5561
5562                 /* Virtual DPCD decompression with DP-to-DP peer device */
5563                 return &immediate_upstream_port->aux;
5564         }
5565
5566         /* Virtual DPCD decompression with DP-to-HDMI or Virtual DP Sink */
5567         if (drm_dp_mst_is_virtual_dpcd(port))
5568                 return &port->aux;
5569
5570         /*
5571          * Synaptics quirk
5572          * Applies to ports for which:
5573          * - Physical aux has Synaptics OUI
5574          * - DPv1.4 or higher
5575          * - Port is on primary branch device
5576          * - Not a VGA adapter (DP_DWN_STRM_PORT_TYPE_ANALOG)
5577          */
5578         if (drm_dp_read_desc(port->mgr->aux, &desc, true))
5579                 return NULL;
5580
5581         if (drm_dp_has_quirk(&desc, 0,
5582                              DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD) &&
5583             port->mgr->dpcd[DP_DPCD_REV] >= DP_DPCD_REV_14 &&
5584             port->parent == port->mgr->mst_primary) {
5585                 u8 downstreamport;
5586
5587                 if (drm_dp_dpcd_read(&port->aux, DP_DOWNSTREAMPORT_PRESENT,
5588                                      &downstreamport, 1) < 0)
5589                         return NULL;
5590
5591                 if ((downstreamport & DP_DWN_STRM_PORT_PRESENT) &&
5592                    ((downstreamport & DP_DWN_STRM_PORT_TYPE_MASK)
5593                      != DP_DWN_STRM_PORT_TYPE_ANALOG))
5594                         return port->mgr->aux;
5595         }
5596
5597         /*
5598          * The check below verifies if the MST sink
5599          * connected to the GPU is capable of DSC -
5600          * therefore the endpoint needs to be
5601          * both DSC and FEC capable.
5602          */
5603         if (drm_dp_dpcd_read(&port->aux,
5604            DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
5605                 return NULL;
5606         if (drm_dp_dpcd_read(&port->aux,
5607            DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
5608                 return NULL;
5609         if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
5610            (endpoint_fec & DP_FEC_CAPABLE))
5611                 return &port->aux;
5612
5613         return NULL;
5614 }
5615 EXPORT_SYMBOL(drm_dp_mst_dsc_aux_for_port);