drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_hdcp.c

   1 /*
   2  * Copyright 2019 Advanced Micro Devices, Inc.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice shall be included in
  12  * all copies or substantial portions of the Software.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  17  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
  18  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  20  * OTHER DEALINGS IN THE SOFTWARE.
  21  *
  22  * Authors: AMD
  23  *
  24  */
  25
  26 #include "amdgpu_dm_hdcp.h"
  27 #include "amdgpu.h"
  28 #include "amdgpu_dm.h"
  29 #include "dm_helpers.h"
  30 #include <drm/drm_hdcp.h>
  31 #include "hdcp_psp.h"
  32
  33 /*
  34  * If the SRM version being loaded is less than or equal to the
  35  * currently loaded SRM, psp will return 0xFFFF as the version
  36  */
  37 #define PSP_SRM_VERSION_MAX 0xFFFF
  38
  39 static bool
  40 lp_write_i2c(void *handle, uint32_t address, const uint8_t *data, uint32_t size)
  41 {
  42
  43         struct dc_link *link = handle;
  44         struct i2c_payload i2c_payloads[] = {{true, address, size, (void *)data} };
  45         struct i2c_command cmd = {i2c_payloads, 1, I2C_COMMAND_ENGINE_HW, link->dc->caps.i2c_speed_in_khz};
  46
  47         return dm_helpers_submit_i2c(link->ctx, link, &cmd);
  48 }
  49
  50 static bool
  51 lp_read_i2c(void *handle, uint32_t address, uint8_t offset, uint8_t *data, uint32_t size)
  52 {
  53         struct dc_link *link = handle;
  54
  55         struct i2c_payload i2c_payloads[] = {{true, address, 1, &offset}, {false, address, size, data} };
  56         struct i2c_command cmd = {i2c_payloads, 2, I2C_COMMAND_ENGINE_HW, link->dc->caps.i2c_speed_in_khz};
  57
  58         return dm_helpers_submit_i2c(link->ctx, link, &cmd);
  59 }
  60
  61 static bool
  62 lp_write_dpcd(void *handle, uint32_t address, const uint8_t *data, uint32_t size)
  63 {
  64         struct dc_link *link = handle;
  65
  66         return dm_helpers_dp_write_dpcd(link->ctx, link, address, data, size);
  67 }
  68
  69 static bool
  70 lp_read_dpcd(void *handle, uint32_t address, uint8_t *data, uint32_t size)
  71 {
  72         struct dc_link *link = handle;
  73
  74         return dm_helpers_dp_read_dpcd(link->ctx, link, address, data, size);
  75 }
  76
  77 static uint8_t *psp_get_srm(struct psp_context *psp, uint32_t *srm_version, uint32_t *srm_size)
  78 {
  79
  80         struct ta_hdcp_shared_memory *hdcp_cmd;
  81
  82         if (!psp->hdcp_context.hdcp_initialized) {
  83                 DRM_WARN("Failed to get hdcp srm. HDCP TA is not initialized.");
  84                 return NULL;
  85         }
  86
  87         hdcp_cmd = (struct ta_hdcp_shared_memory *)psp->hdcp_context.hdcp_shared_buf;
  88         memset(hdcp_cmd, 0, sizeof(struct ta_hdcp_shared_memory));
  89
  90         hdcp_cmd->cmd_id = TA_HDCP_COMMAND__HDCP_GET_SRM;
  91         psp_hdcp_invoke(psp, hdcp_cmd->cmd_id);
  92
  93         if (hdcp_cmd->hdcp_status != TA_HDCP_STATUS__SUCCESS)
  94                 return NULL;
  95
  96         *srm_version = hdcp_cmd->out_msg.hdcp_get_srm.srm_version;
  97         *srm_size = hdcp_cmd->out_msg.hdcp_get_srm.srm_buf_size;
  98
  99
 100         return hdcp_cmd->out_msg.hdcp_get_srm.srm_buf;
 101 }
 102
 103 static int psp_set_srm(struct psp_context *psp, uint8_t *srm, uint32_t srm_size, uint32_t *srm_version)
 104 {
 105
 106         struct ta_hdcp_shared_memory *hdcp_cmd;
 107
 108         if (!psp->hdcp_context.hdcp_initialized) {
 109                 DRM_WARN("Failed to get hdcp srm. HDCP TA is not initialized.");
 110                 return -EINVAL;
 111         }
 112
 113         hdcp_cmd = (struct ta_hdcp_shared_memory *)psp->hdcp_context.hdcp_shared_buf;
 114         memset(hdcp_cmd, 0, sizeof(struct ta_hdcp_shared_memory));
 115
 116         memcpy(hdcp_cmd->in_msg.hdcp_set_srm.srm_buf, srm, srm_size);
 117         hdcp_cmd->in_msg.hdcp_set_srm.srm_buf_size = srm_size;
 118         hdcp_cmd->cmd_id = TA_HDCP_COMMAND__HDCP_SET_SRM;
 119
 120         psp_hdcp_invoke(psp, hdcp_cmd->cmd_id);
 121
 122         if (hdcp_cmd->hdcp_status != TA_HDCP_STATUS__SUCCESS || hdcp_cmd->out_msg.hdcp_set_srm.valid_signature != 1 ||
 123             hdcp_cmd->out_msg.hdcp_set_srm.srm_version == PSP_SRM_VERSION_MAX)
 124                 return -EINVAL;
 125
 126         *srm_version = hdcp_cmd->out_msg.hdcp_set_srm.srm_version;
 127         return 0;
 128 }
 129
 130 static void process_output(struct hdcp_workqueue *hdcp_work)
 131 {
 132         struct mod_hdcp_output output = hdcp_work->output;
 133
 134         if (output.callback_stop)
 135                 cancel_delayed_work(&hdcp_work->callback_dwork);
 136
 137         if (output.callback_needed)
 138                 schedule_delayed_work(&hdcp_work->callback_dwork,
 139                                       msecs_to_jiffies(output.callback_delay));
 140
 141         if (output.watchdog_timer_stop)
 142                 cancel_delayed_work(&hdcp_work->watchdog_timer_dwork);
 143
 144         if (output.watchdog_timer_needed)
 145                 schedule_delayed_work(&hdcp_work->watchdog_timer_dwork,
 146                                       msecs_to_jiffies(output.watchdog_timer_delay));
 147
 148         schedule_delayed_work(&hdcp_work->property_validate_dwork, msecs_to_jiffies(0));
 149 }
 150
 151 static void link_lock(struct hdcp_workqueue *work, bool lock)
 152 {
 153
 154         int i = 0;
 155
 156         for (i = 0; i < work->max_link; i++) {
 157                 if (lock)
 158                         mutex_lock(&work[i].mutex);
 159                 else
 160                         mutex_unlock(&work[i].mutex);
 161         }
 162 }
 163 void hdcp_update_display(struct hdcp_workqueue *hdcp_work,
 164                          unsigned int link_index,
 165                          struct amdgpu_dm_connector *aconnector,
 166                          uint8_t content_type,
 167                          bool enable_encryption)
 168 {
 169         struct hdcp_workqueue *hdcp_w = &hdcp_work[link_index];
 170         struct mod_hdcp_display *display = &hdcp_work[link_index].display;
 171         struct mod_hdcp_link *link = &hdcp_work[link_index].link;
 172         struct mod_hdcp_display_query query;
 173
 174         mutex_lock(&hdcp_w->mutex);
 175         hdcp_w->aconnector = aconnector;
 176
 177         query.display = NULL;
 178         mod_hdcp_query_display(&hdcp_w->hdcp, aconnector->base.index, &query);
 179
 180         if (query.display != NULL) {
 181                 memcpy(display, query.display, sizeof(struct mod_hdcp_display));
 182                 mod_hdcp_remove_display(&hdcp_w->hdcp, aconnector->base.index, &hdcp_w->output);
 183
 184                 hdcp_w->link.adjust.hdcp2.force_type = MOD_HDCP_FORCE_TYPE_0;
 185
 186                 if (enable_encryption) {
 187                         /* Explicitly set the saved SRM as sysfs call will be after we already enabled hdcp
 188                          * (s3 resume case)
 189                          */
 190                         if (hdcp_work->srm_size > 0)
 191                                 psp_set_srm(hdcp_work->hdcp.config.psp.handle, hdcp_work->srm, hdcp_work->srm_size,
 192                                             &hdcp_work->srm_version);
 193
 194                         display->adjust.disable = 0;
 195                         if (content_type == DRM_MODE_HDCP_CONTENT_TYPE0) {
 196                                 hdcp_w->link.adjust.hdcp1.disable = 0;
 197                                 hdcp_w->link.adjust.hdcp2.force_type = MOD_HDCP_FORCE_TYPE_0;
 198                         } else if (content_type == DRM_MODE_HDCP_CONTENT_TYPE1) {
 199                                 hdcp_w->link.adjust.hdcp1.disable = 1;
 200                                 hdcp_w->link.adjust.hdcp2.force_type = MOD_HDCP_FORCE_TYPE_1;
 201                         }
 202
 203                         schedule_delayed_work(&hdcp_w->property_validate_dwork,
 204                                               msecs_to_jiffies(DRM_HDCP_CHECK_PERIOD_MS));
 205                 } else {
 206                         display->adjust.disable = 1;
 207                         hdcp_w->encryption_status = MOD_HDCP_ENCRYPTION_STATUS_HDCP_OFF;
 208                         cancel_delayed_work(&hdcp_w->property_validate_dwork);
 209                 }
 210
 211                 display->state = MOD_HDCP_DISPLAY_ACTIVE;
 212         }
 213
 214         mod_hdcp_add_display(&hdcp_w->hdcp, link, display, &hdcp_w->output);
 215
 216         process_output(hdcp_w);
 217         mutex_unlock(&hdcp_w->mutex);
 218 }
 219
 220 static void hdcp_remove_display(struct hdcp_workqueue *hdcp_work,
 221                          unsigned int link_index,
 222                          struct amdgpu_dm_connector *aconnector)
 223 {
 224         struct hdcp_workqueue *hdcp_w = &hdcp_work[link_index];
 225
 226         mutex_lock(&hdcp_w->mutex);
 227         hdcp_w->aconnector = aconnector;
 228
 229         mod_hdcp_remove_display(&hdcp_w->hdcp, aconnector->base.index, &hdcp_w->output);
 230
 231         process_output(hdcp_w);
 232         mutex_unlock(&hdcp_w->mutex);
 233 }
 234 void hdcp_reset_display(struct hdcp_workqueue *hdcp_work, unsigned int link_index)
 235 {
 236         struct hdcp_workqueue *hdcp_w = &hdcp_work[link_index];
 237
 238         mutex_lock(&hdcp_w->mutex);
 239
 240         mod_hdcp_reset_connection(&hdcp_w->hdcp,  &hdcp_w->output);
 241
 242         cancel_delayed_work(&hdcp_w->property_validate_dwork);
 243         hdcp_w->encryption_status = MOD_HDCP_ENCRYPTION_STATUS_HDCP_OFF;
 244
 245         process_output(hdcp_w);
 246
 247         mutex_unlock(&hdcp_w->mutex);
 248 }
 249
 250 void hdcp_handle_cpirq(struct hdcp_workqueue *hdcp_work, unsigned int link_index)
 251 {
 252         struct hdcp_workqueue *hdcp_w = &hdcp_work[link_index];
 253
 254         schedule_work(&hdcp_w->cpirq_work);
 255 }
 256
 257
 258
 259
 260 static void event_callback(struct work_struct *work)
 261 {
 262         struct hdcp_workqueue *hdcp_work;
 263
 264         hdcp_work = container_of(to_delayed_work(work), struct hdcp_workqueue,
 265                                       callback_dwork);
 266
 267         mutex_lock(&hdcp_work->mutex);
 268
 269         cancel_delayed_work(&hdcp_work->callback_dwork);
 270
 271         mod_hdcp_process_event(&hdcp_work->hdcp, MOD_HDCP_EVENT_CALLBACK,
 272                                &hdcp_work->output);
 273
 274         process_output(hdcp_work);
 275
 276         mutex_unlock(&hdcp_work->mutex);
 277
 278
 279 }
 280 static void event_property_update(struct work_struct *work)
 281 {
 282
 283         struct hdcp_workqueue *hdcp_work = container_of(work, struct hdcp_workqueue, property_update_work);
 284         struct amdgpu_dm_connector *aconnector = hdcp_work->aconnector;
 285         struct drm_device *dev = hdcp_work->aconnector->base.dev;
 286         long ret;
 287
 288         drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
 289         mutex_lock(&hdcp_work->mutex);
 290
 291
 292         if (aconnector->base.state->commit) {
 293                 ret = wait_for_completion_interruptible_timeout(&aconnector->base.state->commit->hw_done, 10 * HZ);
 294
 295                 if (ret == 0) {
 296                         DRM_ERROR("HDCP state unknown! Setting it to DESIRED");
 297                         hdcp_work->encryption_status = MOD_HDCP_ENCRYPTION_STATUS_HDCP_OFF;
 298                 }
 299         }
 300
 301         if (hdcp_work->encryption_status != MOD_HDCP_ENCRYPTION_STATUS_HDCP_OFF) {
 302                 if (aconnector->base.state->hdcp_content_type == DRM_MODE_HDCP_CONTENT_TYPE0 &&
 303                     hdcp_work->encryption_status <= MOD_HDCP_ENCRYPTION_STATUS_HDCP2_TYPE0_ON)
 304                         drm_hdcp_update_content_protection(&aconnector->base, DRM_MODE_CONTENT_PROTECTION_ENABLED);
 305                 else if (aconnector->base.state->hdcp_content_type == DRM_MODE_HDCP_CONTENT_TYPE1 &&
 306                          hdcp_work->encryption_status == MOD_HDCP_ENCRYPTION_STATUS_HDCP2_TYPE1_ON)
 307                         drm_hdcp_update_content_protection(&aconnector->base, DRM_MODE_CONTENT_PROTECTION_ENABLED);
 308         } else {
 309                 drm_hdcp_update_content_protection(&aconnector->base, DRM_MODE_CONTENT_PROTECTION_DESIRED);
 310         }
 311
 312
 313         mutex_unlock(&hdcp_work->mutex);
 314         drm_modeset_unlock(&dev->mode_config.connection_mutex);
 315 }
 316
 317 static void event_property_validate(struct work_struct *work)
 318 {
 319         struct hdcp_workqueue *hdcp_work =
 320                 container_of(to_delayed_work(work), struct hdcp_workqueue, property_validate_dwork);
 321         struct mod_hdcp_display_query query;
 322         struct amdgpu_dm_connector *aconnector = hdcp_work->aconnector;
 323
 324         if (!aconnector)
 325                 return;
 326
 327         mutex_lock(&hdcp_work->mutex);
 328
 329         query.encryption_status = MOD_HDCP_ENCRYPTION_STATUS_HDCP_OFF;
 330         mod_hdcp_query_display(&hdcp_work->hdcp, aconnector->base.index, &query);
 331
 332         if (query.encryption_status != hdcp_work->encryption_status) {
 333                 hdcp_work->encryption_status = query.encryption_status;
 334                 schedule_work(&hdcp_work->property_update_work);
 335         }
 336
 337         mutex_unlock(&hdcp_work->mutex);
 338 }
 339
 340 static void event_watchdog_timer(struct work_struct *work)
 341 {
 342         struct hdcp_workqueue *hdcp_work;
 343
 344         hdcp_work = container_of(to_delayed_work(work),
 345                                       struct hdcp_workqueue,
 346                                       watchdog_timer_dwork);
 347
 348         mutex_lock(&hdcp_work->mutex);
 349
 350         cancel_delayed_work(&hdcp_work->watchdog_timer_dwork);
 351
 352         mod_hdcp_process_event(&hdcp_work->hdcp,
 353                                MOD_HDCP_EVENT_WATCHDOG_TIMEOUT,
 354                                &hdcp_work->output);
 355
 356         process_output(hdcp_work);
 357
 358         mutex_unlock(&hdcp_work->mutex);
 359
 360 }
 361
 362 static void event_cpirq(struct work_struct *work)
 363 {
 364         struct hdcp_workqueue *hdcp_work;
 365
 366         hdcp_work = container_of(work, struct hdcp_workqueue, cpirq_work);
 367
 368         mutex_lock(&hdcp_work->mutex);
 369
 370         mod_hdcp_process_event(&hdcp_work->hdcp, MOD_HDCP_EVENT_CPIRQ, &hdcp_work->output);
 371
 372         process_output(hdcp_work);
 373
 374         mutex_unlock(&hdcp_work->mutex);
 375
 376 }
 377
 378
 379 void hdcp_destroy(struct hdcp_workqueue *hdcp_work)
 380 {
 381         int i = 0;
 382
 383         for (i = 0; i < hdcp_work->max_link; i++) {
 384                 cancel_delayed_work_sync(&hdcp_work[i].callback_dwork);
 385                 cancel_delayed_work_sync(&hdcp_work[i].watchdog_timer_dwork);
 386         }
 387
 388         kfree(hdcp_work->srm);
 389         kfree(hdcp_work->srm_temp);
 390         kfree(hdcp_work);
 391 }
 392
 393
 394 static bool enable_assr(void *handle, struct dc_link *link)
 395 {
 396
 397         struct hdcp_workqueue *hdcp_work = handle;
 398         struct mod_hdcp hdcp = hdcp_work->hdcp;
 399         struct psp_context *psp = hdcp.config.psp.handle;
 400         struct ta_dtm_shared_memory *dtm_cmd;
 401         bool res = true;
 402
 403         if (!psp->dtm_context.dtm_initialized) {
 404                 DRM_INFO("Failed to enable ASSR, DTM TA is not initialized.");
 405                 return false;
 406         }
 407
 408         dtm_cmd = (struct ta_dtm_shared_memory *)psp->dtm_context.dtm_shared_buf;
 409
 410         mutex_lock(&psp->dtm_context.mutex);
 411         memset(dtm_cmd, 0, sizeof(struct ta_dtm_shared_memory));
 412
 413         dtm_cmd->cmd_id = TA_DTM_COMMAND__TOPOLOGY_ASSR_ENABLE;
 414         dtm_cmd->dtm_in_message.topology_assr_enable.display_topology_dig_be_index = link->link_enc_hw_inst;
 415         dtm_cmd->dtm_status = TA_DTM_STATUS__GENERIC_FAILURE;
 416
 417         psp_dtm_invoke(psp, dtm_cmd->cmd_id);
 418
 419         if (dtm_cmd->dtm_status != TA_DTM_STATUS__SUCCESS) {
 420                 DRM_INFO("Failed to enable ASSR");
 421                 res = false;
 422         }
 423
 424         mutex_unlock(&psp->dtm_context.mutex);
 425
 426         return res;
 427 }
 428
 429 static void update_config(void *handle, struct cp_psp_stream_config *config)
 430 {
 431         struct hdcp_workqueue *hdcp_work = handle;
 432         struct amdgpu_dm_connector *aconnector = config->dm_stream_ctx;
 433         int link_index = aconnector->dc_link->link_index;
 434         struct mod_hdcp_display *display = &hdcp_work[link_index].display;
 435         struct mod_hdcp_link *link = &hdcp_work[link_index].link;
 436
 437         if (config->dpms_off) {
 438                 hdcp_remove_display(hdcp_work, link_index, aconnector);
 439                 return;
 440         }
 441
 442         memset(display, 0, sizeof(*display));
 443         memset(link, 0, sizeof(*link));
 444
 445         display->index = aconnector->base.index;
 446         display->state = MOD_HDCP_DISPLAY_ACTIVE;
 447
 448         if (aconnector->dc_sink != NULL)
 449                 link->mode = mod_hdcp_signal_type_to_operation_mode(aconnector->dc_sink->sink_signal);
 450
 451         display->controller = CONTROLLER_ID_D0 + config->otg_inst;
 452         display->dig_fe = config->stream_enc_inst;
 453         link->dig_be = config->link_enc_inst;
 454         link->ddc_line = aconnector->dc_link->ddc_hw_inst + 1;
 455         link->dp.rev = aconnector->dc_link->dpcd_caps.dpcd_rev.raw;
 456         link->dp.mst_supported = config->mst_supported;
 457         display->adjust.disable = 1;
 458         link->adjust.auth_delay = 3;
 459         link->adjust.hdcp1.disable = 0;
 460
 461         hdcp_update_display(hdcp_work, link_index, aconnector, DRM_MODE_HDCP_CONTENT_TYPE0, false);
 462 }
 463
 464
 465 /* NOTE: From the usermodes prospective you only need to call write *ONCE*, the kernel
 466  *      will automatically call once or twice depending on the size
 467  *
 468  * call: "cat file > /sys/class/drm/card0/device/hdcp_srm" from usermode no matter what the size is
 469  *
 470  * The kernel can only send PAGE_SIZE at once and since MAX_SRM_FILE(5120) > PAGE_SIZE(4096),
 471  * srm_data_write can be called multiple times.
 472  *
 473  * sysfs interface doesn't tell us the size we will get so we are sending partial SRMs to psp and on
 474  * the last call we will send the full SRM. PSP will fail on every call before the last.
 475  *
 476  * This means we don't know if the SRM is good until the last call. And because of this limitation we
 477  * cannot throw errors early as it will stop the kernel from writing to sysfs
 478  *
 479  * Example 1:
 480  *      Good SRM size = 5096
 481  *      first call to write 4096 -> PSP fails
 482  *      Second call to write 1000 -> PSP Pass -> SRM is set
 483  *
 484  * Example 2:
 485  *      Bad SRM size = 4096
 486  *      first call to write 4096 -> PSP fails (This is the same as above, but we don't know if this
 487  *      is the last call)
 488  *
 489  * Solution?:
 490  *      1: Parse the SRM? -> It is signed so we don't know the EOF
 491  *      2: We can have another sysfs that passes the size before calling set. -> simpler solution
 492  *      below
 493  *
 494  * Easy Solution:
 495  * Always call get after Set to verify if set was successful.
 496  * +----------------------+
 497  * |   Why it works:      |
 498  * +----------------------+
 499  * PSP will only update its srm if its older than the one we are trying to load.
 500  * Always do set first than get.
 501  *      -if we try to "1. SET" a older version PSP will reject it and we can "2. GET" the newer
 502  *      version and save it
 503  *
 504  *      -if we try to "1. SET" a newer version PSP will accept it and we can "2. GET" the
 505  *      same(newer) version back and save it
 506  *
 507  *      -if we try to "1. SET" a newer version and PSP rejects it. That means the format is
 508  *      incorrect/corrupted and we should correct our SRM by getting it from PSP
 509  */
 510 static ssize_t srm_data_write(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, char *buffer,
 511                               loff_t pos, size_t count)
 512 {
 513         struct hdcp_workqueue *work;
 514         uint32_t srm_version = 0;
 515
 516         work = container_of(bin_attr, struct hdcp_workqueue, attr);
 517         link_lock(work, true);
 518
 519         memcpy(work->srm_temp + pos, buffer, count);
 520
 521         if (!psp_set_srm(work->hdcp.config.psp.handle, work->srm_temp, pos + count, &srm_version)) {
 522                 DRM_DEBUG_DRIVER("HDCP SRM SET version 0x%X", srm_version);
 523                 memcpy(work->srm, work->srm_temp, pos + count);
 524                 work->srm_size = pos + count;
 525                 work->srm_version = srm_version;
 526         }
 527
 528
 529         link_lock(work, false);
 530
 531         return count;
 532 }
 533
 534 static ssize_t srm_data_read(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, char *buffer,
 535                              loff_t pos, size_t count)
 536 {
 537         struct hdcp_workqueue *work;
 538         uint8_t *srm = NULL;
 539         uint32_t srm_version;
 540         uint32_t srm_size;
 541         size_t ret = count;
 542
 543         work = container_of(bin_attr, struct hdcp_workqueue, attr);
 544
 545         link_lock(work, true);
 546
 547         srm = psp_get_srm(work->hdcp.config.psp.handle, &srm_version, &srm_size);
 548
 549         if (!srm) {
 550                 ret = -EINVAL;
 551                 goto ret;
 552         }
 553
 554         if (pos >= srm_size)
 555                 ret = 0;
 556
 557         if (srm_size - pos < count) {
 558                 memcpy(buffer, srm + pos, srm_size - pos);
 559                 ret = srm_size - pos;
 560                 goto ret;
 561         }
 562
 563         memcpy(buffer, srm + pos, count);
 564
 565 ret:
 566         link_lock(work, false);
 567         return ret;
 568 }
 569
 570 /* From the hdcp spec (5.Renewability) SRM needs to be stored in a non-volatile memory.
 571  *
 572  * For example,
 573  *      if Application "A" sets the SRM (ver 2) and we reboot/suspend and later when Application "B"
 574  *      needs to use HDCP, the version in PSP should be SRM(ver 2). So SRM should be persistent
 575  *      across boot/reboots/suspend/resume/shutdown
 576  *
 577  * Currently when the system goes down (suspend/shutdown) the SRM is cleared from PSP. For HDCP we need
 578  * to make the SRM persistent.
 579  *
 580  * -PSP owns the checking of SRM but doesn't have the ability to store it in a non-volatile memory.
 581  * -The kernel cannot write to the file systems.
 582  * -So we need usermode to do this for us, which is why an interface for usermode is needed
 583  *
 584  *
 585  *
 586  * Usermode can read/write to/from PSP using the sysfs interface
 587  * For example:
 588  *      to save SRM from PSP to storage : cat /sys/class/drm/card0/device/hdcp_srm > srmfile
 589  *      to load from storage to PSP: cat srmfile > /sys/class/drm/card0/device/hdcp_srm
 590  */
 591 static const struct bin_attribute data_attr = {
 592         .attr = {.name = "hdcp_srm", .mode = 0664},
 593         .size = PSP_HDCP_SRM_FIRST_GEN_MAX_SIZE, /* Limit SRM size */
 594         .write = srm_data_write,
 595         .read = srm_data_read,
 596 };
 597
 598
 599 struct hdcp_workqueue *hdcp_create_workqueue(struct amdgpu_device *adev, struct cp_psp *cp_psp, struct dc *dc)
 600 {
 601
 602         int max_caps = dc->caps.max_links;
 603         struct hdcp_workqueue *hdcp_work;
 604         int i = 0;
 605
 606         hdcp_work = kcalloc(max_caps, sizeof(*hdcp_work), GFP_KERNEL);
 607         if (hdcp_work == NULL)
 608                 return NULL;
 609
 610         hdcp_work->srm = kcalloc(PSP_HDCP_SRM_FIRST_GEN_MAX_SIZE, sizeof(*hdcp_work->srm), GFP_KERNEL);
 611
 612         if (hdcp_work->srm == NULL)
 613                 goto fail_alloc_context;
 614
 615         hdcp_work->srm_temp = kcalloc(PSP_HDCP_SRM_FIRST_GEN_MAX_SIZE, sizeof(*hdcp_work->srm_temp), GFP_KERNEL);
 616
 617         if (hdcp_work->srm_temp == NULL)
 618                 goto fail_alloc_context;
 619
 620         hdcp_work->max_link = max_caps;
 621
 622         for (i = 0; i < max_caps; i++) {
 623                 mutex_init(&hdcp_work[i].mutex);
 624
 625                 INIT_WORK(&hdcp_work[i].cpirq_work, event_cpirq);
 626                 INIT_WORK(&hdcp_work[i].property_update_work, event_property_update);
 627                 INIT_DELAYED_WORK(&hdcp_work[i].callback_dwork, event_callback);
 628                 INIT_DELAYED_WORK(&hdcp_work[i].watchdog_timer_dwork, event_watchdog_timer);
 629                 INIT_DELAYED_WORK(&hdcp_work[i].property_validate_dwork, event_property_validate);
 630
 631                 hdcp_work[i].hdcp.config.psp.handle = &adev->psp;
 632                 hdcp_work[i].hdcp.config.ddc.handle = dc_get_link_at_index(dc, i);
 633                 hdcp_work[i].hdcp.config.ddc.funcs.write_i2c = lp_write_i2c;
 634                 hdcp_work[i].hdcp.config.ddc.funcs.read_i2c = lp_read_i2c;
 635                 hdcp_work[i].hdcp.config.ddc.funcs.write_dpcd = lp_write_dpcd;
 636                 hdcp_work[i].hdcp.config.ddc.funcs.read_dpcd = lp_read_dpcd;
 637         }
 638
 639         cp_psp->funcs.update_stream_config = update_config;
 640         cp_psp->funcs.enable_assr = enable_assr;
 641         cp_psp->handle = hdcp_work;
 642
 643         /* File created at /sys/class/drm/card0/device/hdcp_srm*/
 644         hdcp_work[0].attr = data_attr;
 645
 646         if (sysfs_create_bin_file(&adev->dev->kobj, &hdcp_work[0].attr))
 647                 DRM_WARN("Failed to create device file hdcp_srm");
 648
 649         return hdcp_work;
 650
 651 fail_alloc_context:
 652         kfree(hdcp_work->srm);
 653         kfree(hdcp_work->srm_temp);
 654         kfree(hdcp_work);
 655
 656         return NULL;
 657
 658
 659
 660 }
 661
 662
 663