drivers/gpu/drm/display/drm_hdcp_helper.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2019 Intel Corporation.
   4  *
   5  * Authors:
   6  * Ramalingam C <[email protected]>
   7  */
   8
   9 #include <linux/device.h>
  10 #include <linux/err.h>
  11 #include <linux/gfp.h>
  12 #include <linux/export.h>
  13 #include <linux/slab.h>
  14 #include <linux/firmware.h>
  15
  16 #include <drm/display/drm_hdcp_helper.h>
  17 #include <drm/drm_sysfs.h>
  18 #include <drm/drm_print.h>
  19 #include <drm/drm_device.h>
  20 #include <drm/drm_property.h>
  21 #include <drm/drm_mode_object.h>
  22 #include <drm/drm_connector.h>
  23
  24 static inline void drm_hdcp_print_ksv(const u8 *ksv)
  25 {
  26         DRM_DEBUG("\t%#02x, %#02x, %#02x, %#02x, %#02x\n",
  27                   ksv[0], ksv[1], ksv[2], ksv[3], ksv[4]);
  28 }
  29
  30 static u32 drm_hdcp_get_revoked_ksv_count(const u8 *buf, u32 vrls_length)
  31 {
  32         u32 parsed_bytes = 0, ksv_count = 0, vrl_ksv_cnt, vrl_sz;
  33
  34         while (parsed_bytes < vrls_length) {
  35                 vrl_ksv_cnt = *buf;
  36                 ksv_count += vrl_ksv_cnt;
  37
  38                 vrl_sz = (vrl_ksv_cnt * DRM_HDCP_KSV_LEN) + 1;
  39                 buf += vrl_sz;
  40                 parsed_bytes += vrl_sz;
  41         }
  42
  43         /*
  44          * When vrls are not valid, ksvs are not considered.
  45          * Hence SRM will be discarded.
  46          */
  47         if (parsed_bytes != vrls_length)
  48                 ksv_count = 0;
  49
  50         return ksv_count;
  51 }
  52
  53 static u32 drm_hdcp_get_revoked_ksvs(const u8 *buf, u8 **revoked_ksv_list,
  54                                      u32 vrls_length)
  55 {
  56         u32 vrl_ksv_cnt, vrl_ksv_sz, vrl_idx = 0;
  57         u32 parsed_bytes = 0, ksv_count = 0;
  58
  59         do {
  60                 vrl_ksv_cnt = *buf;
  61                 vrl_ksv_sz = vrl_ksv_cnt * DRM_HDCP_KSV_LEN;
  62
  63                 buf++;
  64
  65                 DRM_DEBUG("vrl: %d, Revoked KSVs: %d\n", vrl_idx++,
  66                           vrl_ksv_cnt);
  67                 memcpy((*revoked_ksv_list) + (ksv_count * DRM_HDCP_KSV_LEN),
  68                        buf, vrl_ksv_sz);
  69
  70                 ksv_count += vrl_ksv_cnt;
  71                 buf += vrl_ksv_sz;
  72
  73                 parsed_bytes += (vrl_ksv_sz + 1);
  74         } while (parsed_bytes < vrls_length);
  75
  76         return ksv_count;
  77 }
  78
  79 static inline u32 get_vrl_length(const u8 *buf)
  80 {
  81         return drm_hdcp_be24_to_cpu(buf);
  82 }
  83
  84 static int drm_hdcp_parse_hdcp1_srm(const u8 *buf, size_t count,
  85                                     u8 **revoked_ksv_list, u32 *revoked_ksv_cnt)
  86 {
  87         struct hdcp_srm_header *header;
  88         u32 vrl_length, ksv_count;
  89
  90         if (count < (sizeof(struct hdcp_srm_header) +
  91             DRM_HDCP_1_4_VRL_LENGTH_SIZE + DRM_HDCP_1_4_DCP_SIG_SIZE)) {
  92                 DRM_ERROR("Invalid blob length\n");
  93                 return -EINVAL;
  94         }
  95
  96         header = (struct hdcp_srm_header *)buf;
  97         DRM_DEBUG("SRM ID: 0x%x, SRM Ver: 0x%x, SRM Gen No: 0x%x\n",
  98                   header->srm_id,
  99                   be16_to_cpu(header->srm_version), header->srm_gen_no);
 100
 101         WARN_ON(header->reserved);
 102
 103         buf = buf + sizeof(*header);
 104         vrl_length = get_vrl_length(buf);
 105         if (count < (sizeof(struct hdcp_srm_header) + vrl_length) ||
 106             vrl_length < (DRM_HDCP_1_4_VRL_LENGTH_SIZE +
 107                           DRM_HDCP_1_4_DCP_SIG_SIZE)) {
 108                 DRM_ERROR("Invalid blob length or vrl length\n");
 109                 return -EINVAL;
 110         }
 111
 112         /* Length of the all vrls combined */
 113         vrl_length -= (DRM_HDCP_1_4_VRL_LENGTH_SIZE +
 114                        DRM_HDCP_1_4_DCP_SIG_SIZE);
 115
 116         if (!vrl_length) {
 117                 DRM_ERROR("No vrl found\n");
 118                 return -EINVAL;
 119         }
 120
 121         buf += DRM_HDCP_1_4_VRL_LENGTH_SIZE;
 122         ksv_count = drm_hdcp_get_revoked_ksv_count(buf, vrl_length);
 123         if (!ksv_count) {
 124                 DRM_DEBUG("Revoked KSV count is 0\n");
 125                 return 0;
 126         }
 127
 128         *revoked_ksv_list = kcalloc(ksv_count, DRM_HDCP_KSV_LEN, GFP_KERNEL);
 129         if (!*revoked_ksv_list) {
 130                 DRM_ERROR("Out of Memory\n");
 131                 return -ENOMEM;
 132         }
 133
 134         if (drm_hdcp_get_revoked_ksvs(buf, revoked_ksv_list,
 135                                       vrl_length) != ksv_count) {
 136                 *revoked_ksv_cnt = 0;
 137                 kfree(*revoked_ksv_list);
 138                 return -EINVAL;
 139         }
 140
 141         *revoked_ksv_cnt = ksv_count;
 142         return 0;
 143 }
 144
 145 static int drm_hdcp_parse_hdcp2_srm(const u8 *buf, size_t count,
 146                                     u8 **revoked_ksv_list, u32 *revoked_ksv_cnt)
 147 {
 148         struct hdcp_srm_header *header;
 149         u32 vrl_length, ksv_count, ksv_sz;
 150
 151         if (count < (sizeof(struct hdcp_srm_header) +
 152             DRM_HDCP_2_VRL_LENGTH_SIZE + DRM_HDCP_2_DCP_SIG_SIZE)) {
 153                 DRM_ERROR("Invalid blob length\n");
 154                 return -EINVAL;
 155         }
 156
 157         header = (struct hdcp_srm_header *)buf;
 158         DRM_DEBUG("SRM ID: 0x%x, SRM Ver: 0x%x, SRM Gen No: 0x%x\n",
 159                   header->srm_id & DRM_HDCP_SRM_ID_MASK,
 160                   be16_to_cpu(header->srm_version), header->srm_gen_no);
 161
 162         if (header->reserved)
 163                 return -EINVAL;
 164
 165         buf = buf + sizeof(*header);
 166         vrl_length = get_vrl_length(buf);
 167
 168         if (count < (sizeof(struct hdcp_srm_header) + vrl_length) ||
 169             vrl_length < (DRM_HDCP_2_VRL_LENGTH_SIZE +
 170             DRM_HDCP_2_DCP_SIG_SIZE)) {
 171                 DRM_ERROR("Invalid blob length or vrl length\n");
 172                 return -EINVAL;
 173         }
 174
 175         /* Length of the all vrls combined */
 176         vrl_length -= (DRM_HDCP_2_VRL_LENGTH_SIZE +
 177                        DRM_HDCP_2_DCP_SIG_SIZE);
 178
 179         if (!vrl_length) {
 180                 DRM_ERROR("No vrl found\n");
 181                 return -EINVAL;
 182         }
 183
 184         buf += DRM_HDCP_2_VRL_LENGTH_SIZE;
 185         ksv_count = (*buf << 2) | DRM_HDCP_2_KSV_COUNT_2_LSBITS(*(buf + 1));
 186         if (!ksv_count) {
 187                 DRM_DEBUG("Revoked KSV count is 0\n");
 188                 return 0;
 189         }
 190
 191         *revoked_ksv_list = kcalloc(ksv_count, DRM_HDCP_KSV_LEN, GFP_KERNEL);
 192         if (!*revoked_ksv_list) {
 193                 DRM_ERROR("Out of Memory\n");
 194                 return -ENOMEM;
 195         }
 196
 197         ksv_sz = ksv_count * DRM_HDCP_KSV_LEN;
 198         buf += DRM_HDCP_2_NO_OF_DEV_PLUS_RESERVED_SZ;
 199
 200         DRM_DEBUG("Revoked KSVs: %d\n", ksv_count);
 201         memcpy(*revoked_ksv_list, buf, ksv_sz);
 202
 203         *revoked_ksv_cnt = ksv_count;
 204         return 0;
 205 }
 206
 207 static inline bool is_srm_version_hdcp1(const u8 *buf)
 208 {
 209         return *buf == (u8)(DRM_HDCP_1_4_SRM_ID << 4);
 210 }
 211
 212 static inline bool is_srm_version_hdcp2(const u8 *buf)
 213 {
 214         return *buf == (u8)(DRM_HDCP_2_SRM_ID << 4 | DRM_HDCP_2_INDICATOR);
 215 }
 216
 217 static int drm_hdcp_srm_update(const u8 *buf, size_t count,
 218                                u8 **revoked_ksv_list, u32 *revoked_ksv_cnt)
 219 {
 220         if (count < sizeof(struct hdcp_srm_header))
 221                 return -EINVAL;
 222
 223         if (is_srm_version_hdcp1(buf))
 224                 return drm_hdcp_parse_hdcp1_srm(buf, count, revoked_ksv_list,
 225                                                 revoked_ksv_cnt);
 226         else if (is_srm_version_hdcp2(buf))
 227                 return drm_hdcp_parse_hdcp2_srm(buf, count, revoked_ksv_list,
 228                                                 revoked_ksv_cnt);
 229         else
 230                 return -EINVAL;
 231 }
 232
 233 static int drm_hdcp_request_srm(struct drm_device *drm_dev,
 234                                 u8 **revoked_ksv_list, u32 *revoked_ksv_cnt)
 235 {
 236         char fw_name[36] = "display_hdcp_srm.bin";
 237         const struct firmware *fw;
 238         int ret;
 239
 240         ret = request_firmware_direct(&fw, (const char *)fw_name,
 241                                       drm_dev->dev);
 242         if (ret < 0) {
 243                 *revoked_ksv_cnt = 0;
 244                 *revoked_ksv_list = NULL;
 245                 ret = 0;
 246                 goto exit;
 247         }
 248
 249         if (fw->size && fw->data)
 250                 ret = drm_hdcp_srm_update(fw->data, fw->size, revoked_ksv_list,
 251                                           revoked_ksv_cnt);
 252
 253 exit:
 254         release_firmware(fw);
 255         return ret;
 256 }
 257
 258 /**
 259  * drm_hdcp_check_ksvs_revoked - Check the revoked status of the IDs
 260  *
 261  * @drm_dev: drm_device for which HDCP revocation check is requested
 262  * @ksvs: List of KSVs (HDCP receiver IDs)
 263  * @ksv_count: KSV count passed in through @ksvs
 264  *
 265  * This function reads the HDCP System renewability Message(SRM Table)
 266  * from userspace as a firmware and parses it for the revoked HDCP
 267  * KSVs(Receiver IDs) detected by DCP LLC. Once the revoked KSVs are known,
 268  * revoked state of the KSVs in the list passed in by display drivers are
 269  * decided and response is sent.
 270  *
 271  * SRM should be presented in the name of "display_hdcp_srm.bin".
 272  *
 273  * Format of the SRM table, that userspace needs to write into the binary file,
 274  * is defined at:
 275  * 1. Renewability chapter on 55th page of HDCP 1.4 specification
 276  * https://www.digital-cp.com/sites/default/files/specifications/HDCP%20Specification%20Rev1_4_Secure.pdf
 277  * 2. Renewability chapter on 63rd page of HDCP 2.2 specification
 278  * https://www.digital-cp.com/sites/default/files/specifications/HDCP%20on%20HDMI%20Specification%20Rev2_2_Final1.pdf
 279  *
 280  * Returns:
 281  * Count of the revoked KSVs or -ve error number in case of the failure.
 282  */
 283 int drm_hdcp_check_ksvs_revoked(struct drm_device *drm_dev, u8 *ksvs,
 284                                 u32 ksv_count)
 285 {
 286         u32 revoked_ksv_cnt = 0, i, j;
 287         u8 *revoked_ksv_list = NULL;
 288         int ret = 0;
 289
 290         ret = drm_hdcp_request_srm(drm_dev, &revoked_ksv_list,
 291                                    &revoked_ksv_cnt);
 292         if (ret)
 293                 return ret;
 294
 295         /* revoked_ksv_cnt will be zero when above function failed */
 296         for (i = 0; i < revoked_ksv_cnt; i++)
 297                 for  (j = 0; j < ksv_count; j++)
 298                         if (!memcmp(&ksvs[j * DRM_HDCP_KSV_LEN],
 299                                     &revoked_ksv_list[i * DRM_HDCP_KSV_LEN],
 300                                     DRM_HDCP_KSV_LEN)) {
 301                                 DRM_DEBUG("Revoked KSV is ");
 302                                 drm_hdcp_print_ksv(&ksvs[j * DRM_HDCP_KSV_LEN]);
 303                                 ret++;
 304                         }
 305
 306         kfree(revoked_ksv_list);
 307         return ret;
 308 }
 309 EXPORT_SYMBOL_GPL(drm_hdcp_check_ksvs_revoked);
 310
 311 static struct drm_prop_enum_list drm_cp_enum_list[] = {
 312         { DRM_MODE_CONTENT_PROTECTION_UNDESIRED, "Undesired" },
 313         { DRM_MODE_CONTENT_PROTECTION_DESIRED, "Desired" },
 314         { DRM_MODE_CONTENT_PROTECTION_ENABLED, "Enabled" },
 315 };
 316 DRM_ENUM_NAME_FN(drm_get_content_protection_name, drm_cp_enum_list)
 317
 318 static struct drm_prop_enum_list drm_hdcp_content_type_enum_list[] = {
 319         { DRM_MODE_HDCP_CONTENT_TYPE0, "HDCP Type0" },
 320         { DRM_MODE_HDCP_CONTENT_TYPE1, "HDCP Type1" },
 321 };
 322 DRM_ENUM_NAME_FN(drm_get_hdcp_content_type_name,
 323                  drm_hdcp_content_type_enum_list)
 324
 325 /**
 326  * drm_connector_attach_content_protection_property - attach content protection
 327  * property
 328  *
 329  * @connector: connector to attach CP property on.
 330  * @hdcp_content_type: is HDCP Content Type property needed for connector
 331  *
 332  * This is used to add support for content protection on select connectors.
 333  * Content Protection is intentionally vague to allow for different underlying
 334  * technologies, however it is most implemented by HDCP.
 335  *
 336  * When hdcp_content_type is true enum property called HDCP Content Type is
 337  * created (if it is not already) and attached to the connector.
 338  *
 339  * This property is used for sending the protected content's stream type
 340  * from userspace to kernel on selected connectors. Protected content provider
 341  * will decide their type of their content and declare the same to kernel.
 342  *
 343  * Content type will be used during the HDCP 2.2 authentication.
 344  * Content type will be set to &drm_connector_state.hdcp_content_type.
 345  *
 346  * The content protection will be set to &drm_connector_state.content_protection
 347  *
 348  * When kernel triggered content protection state change like DESIRED->ENABLED
 349  * and ENABLED->DESIRED, will use drm_hdcp_update_content_protection() to update
 350  * the content protection state of a connector.
 351  *
 352  * Returns:
 353  * Zero on success, negative errno on failure.
 354  */
 355 int drm_connector_attach_content_protection_property(
 356                 struct drm_connector *connector, bool hdcp_content_type)
 357 {
 358         struct drm_device *dev = connector->dev;
 359         struct drm_property *prop =
 360                         dev->mode_config.content_protection_property;
 361
 362         if (!prop)
 363                 prop = drm_property_create_enum(dev, 0, "Content Protection",
 364                                                 drm_cp_enum_list,
 365                                                 ARRAY_SIZE(drm_cp_enum_list));
 366         if (!prop)
 367                 return -ENOMEM;
 368
 369         drm_object_attach_property(&connector->base, prop,
 370                                    DRM_MODE_CONTENT_PROTECTION_UNDESIRED);
 371         dev->mode_config.content_protection_property = prop;
 372
 373         if (!hdcp_content_type)
 374                 return 0;
 375
 376         prop = dev->mode_config.hdcp_content_type_property;
 377         if (!prop)
 378                 prop = drm_property_create_enum(dev, 0, "HDCP Content Type",
 379                                         drm_hdcp_content_type_enum_list,
 380                                         ARRAY_SIZE(
 381                                         drm_hdcp_content_type_enum_list));
 382         if (!prop)
 383                 return -ENOMEM;
 384
 385         drm_object_attach_property(&connector->base, prop,
 386                                    DRM_MODE_HDCP_CONTENT_TYPE0);
 387         dev->mode_config.hdcp_content_type_property = prop;
 388
 389         return 0;
 390 }
 391 EXPORT_SYMBOL(drm_connector_attach_content_protection_property);
 392
 393 /**
 394  * drm_hdcp_update_content_protection - Updates the content protection state
 395  * of a connector
 396  *
 397  * @connector: drm_connector on which content protection state needs an update
 398  * @val: New state of the content protection property
 399  *
 400  * This function can be used by display drivers, to update the kernel triggered
 401  * content protection state changes of a drm_connector such as DESIRED->ENABLED
 402  * and ENABLED->DESIRED. No uevent for DESIRED->UNDESIRED or ENABLED->UNDESIRED,
 403  * as userspace is triggering such state change and kernel performs it without
 404  * fail.This function update the new state of the property into the connector's
 405  * state and generate an uevent to notify the userspace.
 406  */
 407 void drm_hdcp_update_content_protection(struct drm_connector *connector,
 408                                         u64 val)
 409 {
 410         struct drm_device *dev = connector->dev;
 411         struct drm_connector_state *state = connector->state;
 412
 413         WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
 414         if (state->content_protection == val)
 415                 return;
 416
 417         state->content_protection = val;
 418         drm_sysfs_connector_property_event(connector,
 419                                            dev->mode_config.content_protection_property);
 420 }
 421 EXPORT_SYMBOL(drm_hdcp_update_content_protection);