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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2019 Intel Corporation.
*
* Authors:
* Ramalingam C <ramalingam.c@intel.com>
*/
#include <linux/device.h>
#include <linux/err.h>
#include <linux/gfp.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/firmware.h>
#include <drm/drm_hdcp.h>
#include <drm/drm_sysfs.h>
#include <drm/drm_print.h>
#include <drm/drm_device.h>
struct hdcp_srm {
u32 revoked_ksv_cnt;
u8 *revoked_ksv_list;
/* Mutex to protect above struct member */
struct mutex mutex;
} *srm_data;
static inline void drm_hdcp_print_ksv(const u8 *ksv)
{
DRM_DEBUG("\t%#02x, %#02x, %#02x, %#02x, %#02x\n",
ksv[0], ksv[1], ksv[2], ksv[3], ksv[4]);
}
static u32 drm_hdcp_get_revoked_ksv_count(const u8 *buf, u32 vrls_length)
{
u32 parsed_bytes = 0, ksv_count = 0, vrl_ksv_cnt, vrl_sz;
while (parsed_bytes < vrls_length) {
vrl_ksv_cnt = *buf;
ksv_count += vrl_ksv_cnt;
vrl_sz = (vrl_ksv_cnt * DRM_HDCP_KSV_LEN) + 1;
buf += vrl_sz;
parsed_bytes += vrl_sz;
}
/*
* When vrls are not valid, ksvs are not considered.
* Hence SRM will be discarded.
*/
if (parsed_bytes != vrls_length)
ksv_count = 0;
return ksv_count;
}
static u32 drm_hdcp_get_revoked_ksvs(const u8 *buf, u8 *revoked_ksv_list,
u32 vrls_length)
{
u32 parsed_bytes = 0, ksv_count = 0;
u32 vrl_ksv_cnt, vrl_ksv_sz, vrl_idx = 0;
do {
vrl_ksv_cnt = *buf;
vrl_ksv_sz = vrl_ksv_cnt * DRM_HDCP_KSV_LEN;
buf++;
DRM_DEBUG("vrl: %d, Revoked KSVs: %d\n", vrl_idx++,
vrl_ksv_cnt);
memcpy(revoked_ksv_list, buf, vrl_ksv_sz);
ksv_count += vrl_ksv_cnt;
revoked_ksv_list += vrl_ksv_sz;
buf += vrl_ksv_sz;
parsed_bytes += (vrl_ksv_sz + 1);
} while (parsed_bytes < vrls_length);
return ksv_count;
}
static inline u32 get_vrl_length(const u8 *buf)
{
return drm_hdcp_be24_to_cpu(buf);
}
static int drm_hdcp_parse_hdcp1_srm(const u8 *buf, size_t count)
{
struct hdcp_srm_header *header;
u32 vrl_length, ksv_count;
if (count < (sizeof(struct hdcp_srm_header) +
DRM_HDCP_1_4_VRL_LENGTH_SIZE + DRM_HDCP_1_4_DCP_SIG_SIZE)) {
DRM_ERROR("Invalid blob length\n");
return -EINVAL;
}
header = (struct hdcp_srm_header *)buf;
DRM_DEBUG("SRM ID: 0x%x, SRM Ver: 0x%x, SRM Gen No: 0x%x\n",
header->srm_id,
be16_to_cpu(header->srm_version), header->srm_gen_no);
WARN_ON(header->reserved);
buf = buf + sizeof(*header);
vrl_length = get_vrl_length(buf);
if (count < (sizeof(struct hdcp_srm_header) + vrl_length) ||
vrl_length < (DRM_HDCP_1_4_VRL_LENGTH_SIZE +
DRM_HDCP_1_4_DCP_SIG_SIZE)) {
DRM_ERROR("Invalid blob length or vrl length\n");
return -EINVAL;
}
/* Length of the all vrls combined */
vrl_length -= (DRM_HDCP_1_4_VRL_LENGTH_SIZE +
DRM_HDCP_1_4_DCP_SIG_SIZE);
if (!vrl_length) {
DRM_ERROR("No vrl found\n");
return -EINVAL;
}
buf += DRM_HDCP_1_4_VRL_LENGTH_SIZE;
ksv_count = drm_hdcp_get_revoked_ksv_count(buf, vrl_length);
if (!ksv_count) {
DRM_DEBUG("Revoked KSV count is 0\n");
return count;
}
kfree(srm_data->revoked_ksv_list);
srm_data->revoked_ksv_list = kcalloc(ksv_count, DRM_HDCP_KSV_LEN,
GFP_KERNEL);
if (!srm_data->revoked_ksv_list) {
DRM_ERROR("Out of Memory\n");
return -ENOMEM;
}
if (drm_hdcp_get_revoked_ksvs(buf, srm_data->revoked_ksv_list,
vrl_length) != ksv_count) {
srm_data->revoked_ksv_cnt = 0;
kfree(srm_data->revoked_ksv_list);
return -EINVAL;
}
srm_data->revoked_ksv_cnt = ksv_count;
return count;
}
static int drm_hdcp_parse_hdcp2_srm(const u8 *buf, size_t count)
{
struct hdcp_srm_header *header;
u32 vrl_length, ksv_count, ksv_sz;
if (count < (sizeof(struct hdcp_srm_header) +
DRM_HDCP_2_VRL_LENGTH_SIZE + DRM_HDCP_2_DCP_SIG_SIZE)) {
DRM_ERROR("Invalid blob length\n");
return -EINVAL;
}
header = (struct hdcp_srm_header *)buf;
DRM_DEBUG("SRM ID: 0x%x, SRM Ver: 0x%x, SRM Gen No: 0x%x\n",
header->srm_id & DRM_HDCP_SRM_ID_MASK,
be16_to_cpu(header->srm_version), header->srm_gen_no);
if (header->reserved)
return -EINVAL;
buf = buf + sizeof(*header);
vrl_length = get_vrl_length(buf);
if (count < (sizeof(struct hdcp_srm_header) + vrl_length) ||
vrl_length < (DRM_HDCP_2_VRL_LENGTH_SIZE +
DRM_HDCP_2_DCP_SIG_SIZE)) {
DRM_ERROR("Invalid blob length or vrl length\n");
return -EINVAL;
}
/* Length of the all vrls combined */
vrl_length -= (DRM_HDCP_2_VRL_LENGTH_SIZE +
DRM_HDCP_2_DCP_SIG_SIZE);
if (!vrl_length) {
DRM_ERROR("No vrl found\n");
return -EINVAL;
}
buf += DRM_HDCP_2_VRL_LENGTH_SIZE;
ksv_count = (*buf << 2) | DRM_HDCP_2_KSV_COUNT_2_LSBITS(*(buf + 1));
if (!ksv_count) {
DRM_DEBUG("Revoked KSV count is 0\n");
return count;
}
kfree(srm_data->revoked_ksv_list);
srm_data->revoked_ksv_list = kcalloc(ksv_count, DRM_HDCP_KSV_LEN,
GFP_KERNEL);
if (!srm_data->revoked_ksv_list) {
DRM_ERROR("Out of Memory\n");
return -ENOMEM;
}
ksv_sz = ksv_count * DRM_HDCP_KSV_LEN;
buf += DRM_HDCP_2_NO_OF_DEV_PLUS_RESERVED_SZ;
DRM_DEBUG("Revoked KSVs: %d\n", ksv_count);
memcpy(srm_data->revoked_ksv_list, buf, ksv_sz);
srm_data->revoked_ksv_cnt = ksv_count;
return count;
}
static inline bool is_srm_version_hdcp1(const u8 *buf)
{
return *buf == (u8)(DRM_HDCP_1_4_SRM_ID << 4);
}
static inline bool is_srm_version_hdcp2(const u8 *buf)
{
return *buf == (u8)(DRM_HDCP_2_SRM_ID << 4 | DRM_HDCP_2_INDICATOR);
}
static void drm_hdcp_srm_update(const u8 *buf, size_t count)
{
if (count < sizeof(struct hdcp_srm_header))
return;
if (is_srm_version_hdcp1(buf))
drm_hdcp_parse_hdcp1_srm(buf, count);
else if (is_srm_version_hdcp2(buf))
drm_hdcp_parse_hdcp2_srm(buf, count);
}
void drm_hdcp_request_srm(struct drm_device *drm_dev)
{
char fw_name[36] = "display_hdcp_srm.bin";
const struct firmware *fw;
int ret;
ret = request_firmware_direct(&fw, (const char *)fw_name,
drm_dev->dev);
if (ret < 0)
goto exit;
if (fw->size && fw->data)
drm_hdcp_srm_update(fw->data, fw->size);
exit:
release_firmware(fw);
}
/**
* drm_hdcp_check_ksvs_revoked - Check the revoked status of the IDs
*
* @drm_dev: drm_device for which HDCP revocation check is requested
* @ksvs: List of KSVs (HDCP receiver IDs)
* @ksv_count: KSV count passed in through @ksvs
*
* This function reads the HDCP System renewability Message(SRM Table)
* from userspace as a firmware and parses it for the revoked HDCP
* KSVs(Receiver IDs) detected by DCP LLC. Once the revoked KSVs are known,
* revoked state of the KSVs in the list passed in by display drivers are
* decided and response is sent.
*
* SRM should be presented in the name of "display_hdcp_srm.bin".
*
* Returns:
* TRUE on any of the KSV is revoked, else FALSE.
*/
bool drm_hdcp_check_ksvs_revoked(struct drm_device *drm_dev, u8 *ksvs,
u32 ksv_count)
{
u32 rev_ksv_cnt, cnt, i, j;
u8 *rev_ksv_list;
if (!srm_data)
return false;
mutex_lock(&srm_data->mutex);
drm_hdcp_request_srm(drm_dev);
rev_ksv_cnt = srm_data->revoked_ksv_cnt;
rev_ksv_list = srm_data->revoked_ksv_list;
/* If the Revoked ksv list is empty */
if (!rev_ksv_cnt || !rev_ksv_list) {
mutex_unlock(&srm_data->mutex);
return false;
}
for (cnt = 0; cnt <
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