drivers/gpu/drm/drm_hdcp.c - linux - Git at Google

 // 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>
 #include <drm/drm_property.h>
 #include <drm/drm_mode_object.h>
 #include <drm/drm_connector.h>

 #include "drm_internal.h"

 static 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);
 }

 static 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".
  *
  * Format of the SRM table, that userspace needs to write into the binary file,
  * is defined at:
  * 1. Renewability chapter on 55th page of HDCP 1.4 specification
  * https://www.digital-cp.com/sites/default/files/specifications/HDCP%20Specification%20Rev1_4_Secure.pdf
  * 2. Renewability chapter on 63rd page of HDCP 2.2 specification
  * https://www.digital-cp.com/sites/default/files/specifications/HDCP%20on%20HDMI%20Specification%20Rev2_2_Final1.pdf
  *
  * 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 < ksv_count; cnt++) {
 		rev_ksv_list = srm_data->revoked_ksv_list;
 		for (i = 0; i < rev_ksv_cnt; i++) {
 			for (j = 0; j < DRM_HDCP_KSV_LEN; j++)
 				if (ksvs[j] != rev_ksv_list[j]) {
 					break;
 				} else if (j == (DRM_HDCP_KSV_LEN - 1)) {
 					DRM_DEBUG("Revoked KSV is ");
 					drm_hdcp_print_ksv(ksvs);
 					mutex_unlock(&srm_data->mutex);
 					return true;
 				}
 			/* Move the offset to next KSV in the revoked list */
 			rev_ksv_list += DRM_HDCP_KSV_LEN;
 		}

 		/* Iterate to next ksv_offset */
 		ksvs += DRM_HDCP_KSV_LEN;
 	}
 	mutex_unlock(&srm_data->mutex);
 	return false;
 }
 EXPORT_SYMBOL_GPL(drm_hdcp_check_ksvs_revoked);

 int drm_setup_hdcp_srm(struct class *drm_class)
 {
 	srm_data = kzalloc(sizeof(*srm_data), GFP_KERNEL);
 	if (!srm_data)
 		return -ENOMEM;
 	mutex_init(&srm_data->mutex);

 	return 0;
 }

 void drm_teardown_hdcp_srm(struct class *drm_class)
 {
 	if (srm_data) {
 		kfree(srm_data->revoked_ksv_list);
 		kfree(srm_data);
 	}
 }

 static struct drm_prop_enum_list drm_cp_enum_list[] = {
 	{ DRM_MODE_CONTENT_PROTECTION_UNDESIRED, "Undesired" },
 	{ DRM_MODE_CONTENT_PROTECTION_DESIRED, "Desired" },
 	{ DRM_MODE_CONTENT_PROTECTION_ENABLED, "Enabled" },
 };
 DRM_ENUM_NAME_FN(drm_get_content_protection_name, drm_cp_enum_list)

 static struct drm_prop_enum_list drm_hdcp_content_type_enum_list[] = {
 	{ DRM_MODE_HDCP_CONTENT_TYPE0, "HDCP Type0" },
 	{ DRM_MODE_HDCP_CONTENT_TYPE1, "HDCP Type1" },
 };
 DRM_ENUM_NAME_FN(drm_get_hdcp_content_type_name,
 		 drm_hdcp_content_type_enum_list)

 /**
  * drm_connector_attach_content_protection_property - attach content protection
  * property
  *
  * @connector: connector to attach CP property on.
  * @hdcp_content_type: is HDCP Content Type property needed for connector
  *
  * This is used to add support for content protection on select connectors.
  * Content Protection is intentionally vague to allow for different underlying
  * technologies, however it is most implemented by HDCP.
  *
  * When hdcp_content_type is true enum property called HDCP Content Type is
  * created (if it is not already) and attached to the connector.
  *
  * This property is used for sending the protected content's stream type
  * from userspace to kernel on selected connectors. Protected content provider
  * will decide their type of their content and declare the same to kernel.
  *
  * Content type will be used during the HDCP 2.2 authentication.
  * Content type will be set to &drm_connector_state.hdcp_content_type.
  *
  * The content protection will be set to &drm_connector_state.content_protection
  *
  * When kernel triggered content protection state change like DESIRED->ENABLED
  * and ENABLED->DESIRED, will use drm_hdcp_update_content_protection() to update
  * the content protection state of a connector.
  *
  * Returns:
  * Zero on success, negative errno on failure.
  */
 int drm_connector_attach_content_protection_property(
 		struct drm_connector *connector, bool hdcp_content_type)
 {
 	struct drm_device *dev = connector->dev;
 	struct drm_property *prop =
 			dev->mode_config.content_protection_property;

 	if (!prop)
 		prop = drm_property_create_enum(dev, 0, "Content Protection",
 						drm_cp_enum_list,
 						ARRAY_SIZE(drm_cp_enum_list));
 	if (!prop)
 		return -ENOMEM;

 	drm_object_attach_property(&connector->base, prop,
 				   DRM_MODE_CONTENT_PROTECTION_UNDESIRED);
 	dev->mode_config.content_protection_property = prop;

 	if (!hdcp_content_type)
 		return 0;

 	prop = dev->mode_config.hdcp_content_type_property;
 	if (!prop)
 		prop = drm_property_create_enum(dev, 0, "HDCP Content Type",
 					drm_hdcp_content_type_enum_list,
 					ARRAY_SIZE(
 					drm_hdcp_content_type_enum_list));
 	if (!prop)
 		return -ENOMEM;

 	drm_object_attach_property(&connector->base, prop,
 				   DRM_MODE_HDCP_CONTENT_TYPE0);
 	dev->mode_config.hdcp_content_type_property = prop;

 	return 0;
 }
 EXPORT_SYMBOL(drm_connector_attach_content_protection_property);

 /**
  * drm_hdcp_update_content_protection - Updates the content protection state
  * of a connector
  *
  * @connector: drm_connector on which content protection state needs an update
  * @val: New state of the content protection property
  *
  * This function can be used by display drivers, to update the kernel triggered
  * content protection state changes of a drm_connector such as DESIRED->ENABLED
  * and ENABLED->DESIRED. No uevent for DESIRED->UNDESIRED or ENABLED->UNDESIRED,
  * as userspace is triggering such state change and kernel performs it without
  * fail.This function update the new state of the property into the connector's
  * state and generate an uevent to notify the userspace.
  */
 void drm_hdcp_update_content_protection(struct drm_connector *connector,
 					u64 val)
 {
 	struct drm_device *dev = connector->dev;
 	struct drm_connector_state *state = connector->state;

 	WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
 	if (state->content_protection == val)
 		return;

 	state->content_protection = val;
 	drm_sysfs_connector_status_event(connector,
 				 dev->mode_config.content_protection_property);
 }
 EXPORT_SYMBOL(drm_hdcp_update_content_protection);
	// 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>
	#include <drm/drm_property.h>
	#include <drm/drm_mode_object.h>
	#include <drm/drm_connector.h>

	#include "drm_internal.h"

	static 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);
	}

	static 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".
	*
	* Format of the SRM table, that userspace needs to write into the binary file,
	* is defined at:
	* 1. Renewability chapter on 55th page of HDCP 1.4 specification
	* https://www.digital-cp.com/sites/default/files/specifications/HDCP%20Specification%20Rev1_4_Secure.pdf
	* 2. Renewability chapter on 63rd page of HDCP 2.2 specification
	* https://www.digital-cp.com/sites/default/files/specifications/HDCP%20on%20HDMI%20Specification%20Rev2_2_Final1.pdf
	*
	* 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 < ksv_count; cnt++) {
	rev_ksv_list = srm_data->revoked_ksv_list;
	for (i = 0; i < rev_ksv_cnt; i++) {
	for (j = 0; j < DRM_HDCP_KSV_LEN; j++)
	if (ksvs[j] != rev_ksv_list[j]) {
	break;
	} else if (j == (DRM_HDCP_KSV_LEN - 1)) {
	DRM_DEBUG("Revoked KSV is ");
	drm_hdcp_print_ksv(ksvs);
	mutex_unlock(&srm_data->mutex);
	return true;
	}
	/* Move the offset to next KSV in the revoked list */
	rev_ksv_list += DRM_HDCP_KSV_LEN;
	}

	/* Iterate to next ksv_offset */
	ksvs += DRM_HDCP_KSV_LEN;
	}
	mutex_unlock(&srm_data->mutex);
	return false;
	}
	EXPORT_SYMBOL_GPL(drm_hdcp_check_ksvs_revoked);

	int drm_setup_hdcp_srm(struct class *drm_class)
	{
	srm_data = kzalloc(sizeof(*srm_data), GFP_KERNEL);
	if (!srm_data)
	return -ENOMEM;
	mutex_init(&srm_data->mutex);

	return 0;
	}

	void drm_teardown_hdcp_srm(struct class *drm_class)
	{
	if (srm_data) {
	kfree(srm_data->revoked_ksv_list);
	kfree(srm_data);
	}
	}

	static struct drm_prop_enum_list drm_cp_enum_list[] = {
	{ DRM_MODE_CONTENT_PROTECTION_UNDESIRED, "Undesired" },
	{ DRM_MODE_CONTENT_PROTECTION_DESIRED, "Desired" },
	{ DRM_MODE_CONTENT_PROTECTION_ENABLED, "Enabled" },
	};
	DRM_ENUM_NAME_FN(drm_get_content_protection_name, drm_cp_enum_list)

	static struct drm_prop_enum_list drm_hdcp_content_type_enum_list[] = {
	{ DRM_MODE_HDCP_CONTENT_TYPE0, "HDCP Type0" },
	{ DRM_MODE_HDCP_CONTENT_TYPE1, "HDCP Type1" },
	};
	DRM_ENUM_NAME_FN(drm_get_hdcp_content_type_name,
	drm_hdcp_content_type_enum_list)

	/**
	* drm_connector_attach_content_protection_property - attach content protection
	* property
	*
	* @connector: connector to attach CP property on.
	* @hdcp_content_type: is HDCP Content Type property needed for connector
	*
	* This is used to add support for content protection on select connectors.
	* Content Protection is intentionally vague to allow for different underlying
	* technologies, however it is most implemented by HDCP.
	*
	* When hdcp_content_type is true enum property called HDCP Content Type is
	* created (if it is not already) and attached to the connector.
	*
	* This property is used for sending the protected content's stream type
	* from userspace to kernel on selected connectors. Protected content provider
	* will decide their type of their content and declare the same to kernel.
	*
	* Content type will be used during the HDCP 2.2 authentication.
	* Content type will be set to &drm_connector_state.hdcp_content_type.
	*
	* The content protection will be set to &drm_connector_state.content_protection
	*
	* When kernel triggered content protection state change like DESIRED->ENABLED
	* and ENABLED->DESIRED, will use drm_hdcp_update_content_protection() to update
	* the content protection state of a connector.
	*
	* Returns:
	* Zero on success, negative errno on failure.
	*/
	int drm_connector_attach_content_protection_property(
	struct drm_connector *connector, bool hdcp_content_type)
	{
	struct drm_device *dev = connector->dev;
	struct drm_property *prop =
	dev->mode_config.content_protection_property;

	if (!prop)
	prop = drm_property_create_enum(dev, 0, "Content Protection",
	drm_cp_enum_list,
	ARRAY_SIZE(drm_cp_enum_list));
	if (!prop)
	return -ENOMEM;

	drm_object_attach_property(&connector->base, prop,
	DRM_MODE_CONTENT_PROTECTION_UNDESIRED);
	dev->mode_config.content_protection_property = prop;

	if (!hdcp_content_type)
	return 0;

	prop = dev->mode_config.hdcp_content_type_property;
	if (!prop)
	prop = drm_property_create_enum(dev, 0, "HDCP Content Type",
	drm_hdcp_content_type_enum_list,
	ARRAY_SIZE(
	drm_hdcp_content_type_enum_list));
	if (!prop)
	return -ENOMEM;

	drm_object_attach_property(&connector->base, prop,
	DRM_MODE_HDCP_CONTENT_TYPE0);
	dev->mode_config.hdcp_content_type_property = prop;

	return 0;
	}
	EXPORT_SYMBOL(drm_connector_attach_content_protection_property);

	/**
	* drm_hdcp_update_content_protection - Updates the content protection state
	* of a connector
	*
	* @connector: drm_connector on which content protection state needs an update
	* @val: New state of the content protection property
	*
	* This function can be used by display drivers, to update the kernel triggered
	* content protection state changes of a drm_connector such as DESIRED->ENABLED
	* and ENABLED->DESIRED. No uevent for DESIRED->UNDESIRED or ENABLED->UNDESIRED,
	* as userspace is triggering such state change and kernel performs it without
	* fail.This function update the new state of the property into the connector's
	* state and generate an uevent to notify the userspace.
	*/
	void drm_hdcp_update_content_protection(struct drm_connector *connector,
	u64 val)
	{
	struct drm_device *dev = connector->dev;
	struct drm_connector_state *state = connector->state;

	WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
	if (state->content_protection == val)
	return;

	state->content_protection = val;
	drm_sysfs_connector_status_event(connector,
	dev->mode_config.content_protection_property);
	}
	EXPORT_SYMBOL(drm_hdcp_update_content_protection);