drivers/gpu/drm/drm_dp_mst_topology.c

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