LXR linux/drivers/gpu/drm/drm

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (C) 2019 Intel Corporation.
   4 *
   5 * Authors:
   6 * Ramalingam C <ramalingam.c@intel.com>
   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/drm_hdcp.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#include "drm_internal.h"
  25
  26static struct hdcp_srm {
  27        u32 revoked_ksv_cnt;
  28        u8 *revoked_ksv_list;
  29
  30        /* Mutex to protect above struct member */
  31        struct mutex mutex;
  32} *srm_data;
  33
  34static inline void drm_hdcp_print_ksv(const u8 *ksv)
  35{
  36        DRM_DEBUG("\t%#02x, %#02x, %#02x, %#02x, %#02x\n",
  37                  ksv[0], ksv[1], ksv[2], ksv[3], ksv[4]);
  38}
  39
  40static u32 drm_hdcp_get_revoked_ksv_count(const u8 *buf, u32 vrls_length)
  41{
  42        u32 parsed_bytes = 0, ksv_count = 0, vrl_ksv_cnt, vrl_sz;
  43
  44        while (parsed_bytes < vrls_length) {
  45                vrl_ksv_cnt = *buf;
  46                ksv_count += vrl_ksv_cnt;
  47
  48                vrl_sz = (vrl_ksv_cnt * DRM_HDCP_KSV_LEN) + 1;
  49                buf += vrl_sz;
  50                parsed_bytes += vrl_sz;
  51        }
  52
  53        /*
  54         * When vrls are not valid, ksvs are not considered.
  55         * Hence SRM will be discarded.
  56         */
  57        if (parsed_bytes != vrls_length)
  58                ksv_count = 0;
  59
  60        return ksv_count;
  61}
  62
  63static u32 drm_hdcp_get_revoked_ksvs(const u8 *buf, u8 *revoked_ksv_list,
  64                                     u32 vrls_length)
  65{
  66        u32 parsed_bytes = 0, ksv_count = 0;
  67        u32 vrl_ksv_cnt, vrl_ksv_sz, vrl_idx = 0;
  68
  69        do {
  70                vrl_ksv_cnt = *buf;
  71                vrl_ksv_sz = vrl_ksv_cnt * DRM_HDCP_KSV_LEN;
  72
  73                buf++;
  74
  75                DRM_DEBUG("vrl: %d, Revoked KSVs: %d\n", vrl_idx++,
  76                          vrl_ksv_cnt);
  77                memcpy(revoked_ksv_list, buf, vrl_ksv_sz);
  78
  79                ksv_count += vrl_ksv_cnt;
  80                revoked_ksv_list += vrl_ksv_sz;
  81                buf += vrl_ksv_sz;
  82
  83                parsed_bytes += (vrl_ksv_sz + 1);
  84        } while (parsed_bytes < vrls_length);
  85
  86        return ksv_count;
  87}
  88
  89static inline u32 get_vrl_length(const u8 *buf)
  90{
  91        return drm_hdcp_be24_to_cpu(buf);
  92}
  93
  94static int drm_hdcp_parse_hdcp1_srm(const u8 *buf, size_t count)
  95{
  96        struct hdcp_srm_header *header;
  97        u32 vrl_length, ksv_count;
  98
  99        if (count < (sizeof(struct hdcp_srm_header) +
 100            DRM_HDCP_1_4_VRL_LENGTH_SIZE + DRM_HDCP_1_4_DCP_SIG_SIZE)) {
 101                DRM_ERROR("Invalid blob length\n");
 102                return -EINVAL;
 103        }
 104
 105        header = (struct hdcp_srm_header *)buf;
 106        DRM_DEBUG("SRM ID: 0x%x, SRM Ver: 0x%x, SRM Gen No: 0x%x\n",
 107                  header->srm_id,
 108                  be16_to_cpu(header->srm_version), header->srm_gen_no);
 109
 110        WARN_ON(header->reserved);
 111
 112        buf = buf + sizeof(*header);
 113        vrl_length = get_vrl_length(buf);
 114        if (count < (sizeof(struct hdcp_srm_header) + vrl_length) ||
 115            vrl_length < (DRM_HDCP_1_4_VRL_LENGTH_SIZE +
 116                          DRM_HDCP_1_4_DCP_SIG_SIZE)) {
 117                DRM_ERROR("Invalid blob length or vrl length\n");
 118                return -EINVAL;
 119        }
 120
 121        /* Length of the all vrls combined */
 122        vrl_length -= (DRM_HDCP_1_4_VRL_LENGTH_SIZE +
 123                       DRM_HDCP_1_4_DCP_SIG_SIZE);
 124
 125        if (!vrl_length) {
 126                DRM_ERROR("No vrl found\n");
 127                return -EINVAL;
 128        }
 129
 130        buf += DRM_HDCP_1_4_VRL_LENGTH_SIZE;
 131        ksv_count = drm_hdcp_get_revoked_ksv_count(buf, vrl_length);
 132        if (!ksv_count) {
 133                DRM_DEBUG("Revoked KSV count is 0\n");
 134                return count;
 135        }
 136
 137        kfree(srm_data->revoked_ksv_list);
 138        srm_data->revoked_ksv_list = kcalloc(ksv_count, DRM_HDCP_KSV_LEN,
 139                                             GFP_KERNEL);
 140        if (!srm_data->revoked_ksv_list) {
 141                DRM_ERROR("Out of Memory\n");
 142                return -ENOMEM;
 143        }
 144
 145        if (drm_hdcp_get_revoked_ksvs(buf, srm_data->revoked_ksv_list,
 146                                      vrl_length) != ksv_count) {
 147                srm_data->revoked_ksv_cnt = 0;
 148                kfree(srm_data->revoked_ksv_list);
 149                return -EINVAL;
 150        }
 151
 152        srm_data->revoked_ksv_cnt = ksv_count;
 153        return count;
 154}
 155
 156static int drm_hdcp_parse_hdcp2_srm(const u8 *buf, size_t count)
 157{
 158        struct hdcp_srm_header *header;
 159        u32 vrl_length, ksv_count, ksv_sz;
 160
 161        if (count < (sizeof(struct hdcp_srm_header) +
 162            DRM_HDCP_2_VRL_LENGTH_SIZE + DRM_HDCP_2_DCP_SIG_SIZE)) {
 163                DRM_ERROR("Invalid blob length\n");
 164                return -EINVAL;
 165        }
 166
 167        header = (struct hdcp_srm_header *)buf;
 168        DRM_DEBUG("SRM ID: 0x%x, SRM Ver: 0x%x, SRM Gen No: 0x%x\n",
 169                  header->srm_id & DRM_HDCP_SRM_ID_MASK,
 170                  be16_to_cpu(header->srm_version), header->srm_gen_no);
 171
 172        if (header->reserved)
 173                return -EINVAL;
 174
 175        buf = buf + sizeof(*header);
 176        vrl_length = get_vrl_length(buf);
 177
 178        if (count < (sizeof(struct hdcp_srm_header) + vrl_length) ||
 179            vrl_length < (DRM_HDCP_2_VRL_LENGTH_SIZE +
 180            DRM_HDCP_2_DCP_SIG_SIZE)) {
 181                DRM_ERROR("Invalid blob length or vrl length\n");
 182                return -EINVAL;
 183        }
 184
 185        /* Length of the all vrls combined */
 186        vrl_length -= (DRM_HDCP_2_VRL_LENGTH_SIZE +
 187                       DRM_HDCP_2_DCP_SIG_SIZE);
 188
 189        if (!vrl_length) {
 190                DRM_ERROR("No vrl found\n");
 191                return -EINVAL;
 192        }
 193
 194        buf += DRM_HDCP_2_VRL_LENGTH_SIZE;
 195        ksv_count = (*buf << 2) | DRM_HDCP_2_KSV_COUNT_2_LSBITS(*(buf + 1));
 196        if (!ksv_count) {
 197                DRM_DEBUG("Revoked KSV count is 0\n");
 198                return count;
 199        }
 200
 201        kfree(srm_data->revoked_ksv_list);
 202        srm_data->revoked_ksv_list = kcalloc(ksv_count, DRM_HDCP_KSV_LEN,
 203                                             GFP_KERNEL);
 204        if (!srm_data->revoked_ksv_list) {
 205                DRM_ERROR("Out of Memory\n");
 206                return -ENOMEM;
 207        }
 208
 209        ksv_sz = ksv_count * DRM_HDCP_KSV_LEN;
 210        buf += DRM_HDCP_2_NO_OF_DEV_PLUS_RESERVED_SZ;
 211
 212        DRM_DEBUG("Revoked KSVs: %d\n", ksv_count);
 213        memcpy(srm_data->revoked_ksv_list, buf, ksv_sz);
 214
 215        srm_data->revoked_ksv_cnt = ksv_count;
 216        return count;
 217}
 218
 219static inline bool is_srm_version_hdcp1(const u8 *buf)
 220{
 221        return *buf == (u8)(DRM_HDCP_1_4_SRM_ID << 4);
 222}
 223
 224static inline bool is_srm_version_hdcp2(const u8 *buf)
 225{
 226        return *buf == (u8)(DRM_HDCP_2_SRM_ID << 4 | DRM_HDCP_2_INDICATOR);
 227}
 228
 229static void drm_hdcp_srm_update(const u8 *buf, size_t count)
 230{
 231        if (count < sizeof(struct hdcp_srm_header))
 232                return;
 233
 234        if (is_srm_version_hdcp1(buf))
 235                drm_hdcp_parse_hdcp1_srm(buf, count);
 236        else if (is_srm_version_hdcp2(buf))
 237                drm_hdcp_parse_hdcp2_srm(buf, count);
 238}
 239
 240static void drm_hdcp_request_srm(struct drm_device *drm_dev)
 241{
 242        char fw_name[36] = "display_hdcp_srm.bin";
 243        const struct firmware *fw;
 244
 245        int ret;
 246
 247        ret = request_firmware_direct(&fw, (const char *)fw_name,
 248                                      drm_dev->dev);
 249        if (ret < 0)
 250                goto exit;
 251
 252        if (fw->size && fw->data)
 253                drm_hdcp_srm_update(fw->data, fw->size);
 254
 255exit:
 256        release_firmware(fw);
 257}
 258
 259/**
 260 * drm_hdcp_check_ksvs_revoked - Check the revoked status of the IDs
 261 *
 262 * @drm_dev: drm_device for which HDCP revocation check is requested
 263 * @ksvs: List of KSVs (HDCP receiver IDs)
 264 * @ksv_count: KSV count passed in through @ksvs
 265 *
 266 * This function reads the HDCP System renewability Message(SRM Table)
 267 * from userspace as a firmware and parses it for the revoked HDCP
 268 * KSVs(Receiver IDs) detected by DCP LLC. Once the revoked KSVs are known,
 269 * revoked state of the KSVs in the list passed in by display drivers are
 270 * decided and response is sent.
 271 *
 272 * SRM should be presented in the name of "display_hdcp_srm.bin".
 273 *
 274 * Returns:
 275 * TRUE on any of the KSV is revoked, else FALSE.
 276 */
 277bool drm_hdcp_check_ksvs_revoked(struct drm_device *drm_dev, u8 *ksvs,
 278                                 u32 ksv_count)
 279{
 280        u32 rev_ksv_cnt, cnt, i, j;
 281        u8 *rev_ksv_list;
 282
 283        if (!srm_data)
 284                return false;
 285
 286        mutex_lock(&srm_data->mutex);
 287        drm_hdcp_request_srm(drm_dev);
 288
 289        rev_ksv_cnt = srm_data->revoked_ksv_cnt;
 290        rev_ksv_list = srm_data->revoked_ksv_list;
 291
 292        /* If the Revoked ksv list is empty */
 293        if (!rev_ksv_cnt || !rev_ksv_list) {
 294                mutex_unlock(&srm_data->mutex);
 295                return false;
 296        }
 297
 298        for  (cnt = 0; cnt < ksv_count; cnt++) {
 299                rev_ksv_list = srm_data->revoked_ksv_list;
 300                for (i = 0; i < rev_ksv_cnt; i++) {
 301                        for (j = 0; j < DRM_HDCP_KSV_LEN; j++)
 302                                if (ksvs[j] != rev_ksv_list[j]) {
 303                                        break;
 304                                } else if (j == (DRM_HDCP_KSV_LEN - 1)) {
 305                                        DRM_DEBUG("Revoked KSV is ");
 306                                        drm_hdcp_print_ksv(ksvs);
 307                                        mutex_unlock(&srm_data->mutex);
 308                                        return true;
 309                                }
 310                        /* Move the offset to next KSV in the revoked list */
 311                        rev_ksv_list += DRM_HDCP_KSV_LEN;
 312                }
 313
 314                /* Iterate to next ksv_offset */
 315                ksvs += DRM_HDCP_KSV_LEN;
 316        }
 317        mutex_unlock(&srm_data->mutex);
 318        return false;
 319}
 320EXPORT_SYMBOL_GPL(drm_hdcp_check_ksvs_revoked);
 321
 322int drm_setup_hdcp_srm(struct class *drm_class)
 323{
 324        srm_data = kzalloc(sizeof(*srm_data), GFP_KERNEL);
 325        if (!srm_data)
 326                return -ENOMEM;
 327        mutex_init(&srm_data->mutex);
 328
 329        return 0;
 330}
 331
 332void drm_teardown_hdcp_srm(struct class *drm_class)
 333{
 334        if (srm_data) {
 335                kfree(srm_data->revoked_ksv_list);
 336                kfree(srm_data);
 337        }
 338}
 339
 340static struct drm_prop_enum_list drm_cp_enum_list[] = {
 341        { DRM_MODE_CONTENT_PROTECTION_UNDESIRED, "Undesired" },
 342        { DRM_MODE_CONTENT_PROTECTION_DESIRED, "Desired" },
 343        { DRM_MODE_CONTENT_PROTECTION_ENABLED, "Enabled" },
 344};
 345DRM_ENUM_NAME_FN(drm_get_content_protection_name, drm_cp_enum_list)
 346
 347/**
 348 * drm_connector_attach_content_protection_property - attach content protection
 349 * property
 350 *
 351 * @connector: connector to attach CP property on.
 352 *
 353 * This is used to add support for content protection on select connectors.
 354 * Content Protection is intentionally vague to allow for different underlying
 355 * technologies, however it is most implemented by HDCP.
 356 *
 357 * The content protection will be set to &drm_connector_state.content_protection
 358 *
 359 * Returns:
 360 * Zero on success, negative errno on failure.
 361 */
 362int drm_connector_attach_content_protection_property(
 363                struct drm_connector *connector)
 364{
 365        struct drm_device *dev = connector->dev;
 366        struct drm_property *prop =
 367                        dev->mode_config.content_protection_property;
 368
 369        if (!prop)
 370                prop = drm_property_create_enum(dev, 0, "Content Protection",
 371                                                drm_cp_enum_list,
 372                                                ARRAY_SIZE(drm_cp_enum_list));
 373        if (!prop)
 374                return -ENOMEM;
 375
 376        drm_object_attach_property(&connector->base, prop,
 377                                   DRM_MODE_CONTENT_PROTECTION_UNDESIRED);
 378        dev->mode_config.content_protection_property = prop;
 379
 380        return 0;
 381}
 382EXPORT_SYMBOL(drm_connector_attach_content_protection_property);
 383