drm/display: Move HDCP helpers into display-helper module

Move DRM's HDCP helper library into the display/ subdirectory and add
it to DRM's display helpers. Split the header file into core and helpers.
Update all affected drivers. No functional changes.

v3:
	* fix Kconfig dependencies
v2:
	* fix include statements (Jani, Javier)
	* update Kconfig symbols

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220421073108.19226-7-tzimmermann@suse.de

3 files changed, 428 insertions, 0 deletions

diff --git a/drivers/gpu/drm/display/Kconfig b/drivers/gpu/drm/display/Kconfig
index fcd9ffd39f26..4406af5cc8bb 100644
--- a/drivers/gpu/drm/display/Kconfig
+++ b/drivers/gpu/drm/display/Kconfig
@@ -17,6 +17,12 @@ config DRM_DISPLAY_DP_HELPER
 	help
 	  DRM display helpers for DisplayPort.
 
+config DRM_DISPLAY_HDCP_HELPER
+	bool
+	depends on DRM_DISPLAY_HELPER
+	help
+	  DRM display helpers for HDCP.
+
 config DRM_DP_AUX_CHARDEV
 	bool "DRM DP AUX Interface"
 	depends on DRM
diff --git a/drivers/gpu/drm/display/Makefile b/drivers/gpu/drm/display/Makefile
index 4f4e35034960..abeb5ad8c351 100644
--- a/drivers/gpu/drm/display/Makefile
+++ b/drivers/gpu/drm/display/Makefile
@@ -7,6 +7,7 @@ drm_display_helper-$(CONFIG_DRM_DISPLAY_DP_HELPER) += drm_dp_dual_mode_helper.o
 						      drm_dp_helper.o \
 						      drm_dp_mst_topology.o \
 						      drm_dsc_helper.o
+drm_display_helper-$(CONFIG_DRM_DISPLAY_HDCP_HELPER) += drm_hdcp_helper.o
 drm_display_helper-$(CONFIG_DRM_DP_AUX_CHARDEV) += drm_dp_aux_dev.o
 drm_display_helper-$(CONFIG_DRM_DP_CEC) += drm_dp_cec.o
 
diff --git a/drivers/gpu/drm/display/drm_hdcp_helper.c b/drivers/gpu/drm/display/drm_hdcp_helper.c
new file mode 100644
index 000000000000..e78999c72bd7
--- /dev/null
+++ b/drivers/gpu/drm/display/drm_hdcp_helper.c
@@ -0,0 +1,421 @@
+// 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/display/drm_hdcp_helper.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>
+
+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 vrl_ksv_cnt, vrl_ksv_sz, vrl_idx = 0;
+	u32 parsed_bytes = 0, ksv_count = 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) + (ksv_count * DRM_HDCP_KSV_LEN),
+		       buf, vrl_ksv_sz);
+
+		ksv_count += vrl_ksv_cnt;
+		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,
+				    u8 **revoked_ksv_list, u32 *revoked_ksv_cnt)
+{
+	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 0;
+	}
+
+	*revoked_ksv_list = kcalloc(ksv_count, DRM_HDCP_KSV_LEN, GFP_KERNEL);
+	if (!*revoked_ksv_list) {
+		DRM_ERROR("Out of Memory\n");
+		return -ENOMEM;
+	}
+
+	if (drm_hdcp_get_revoked_ksvs(buf, revoked_ksv_list,
+				      vrl_length) != ksv_count) {
+		*revoked_ksv_cnt = 0;
+		kfree(*revoked_ksv_list);
+		return -EINVAL;
+	}
+
+	*revoked_ksv_cnt = ksv_count;
+	return 0;
+}
+
+static int drm_hdcp_parse_hdcp2_srm(const u8 *buf, size_t count,
+				    u8 **revoked_ksv_list, u32 *revoked_ksv_cnt)
+{
+	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 0;
+	}
+
+	*revoked_ksv_list = kcalloc(ksv_count, DRM_HDCP_KSV_LEN, GFP_KERNEL);
+	if (!*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(*revoked_ksv_list, buf, ksv_sz);
+
+	*revoked_ksv_cnt = ksv_count;
+	return 0;
+}
+
+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 int drm_hdcp_srm_update(const u8 *buf, size_t count,
+			       u8 **revoked_ksv_list, u32 *revoked_ksv_cnt)
+{
+	if (count < sizeof(struct hdcp_srm_header))
+		return -EINVAL;
+
+	if (is_srm_version_hdcp1(buf))
+		return drm_hdcp_parse_hdcp1_srm(buf, count, revoked_ksv_list,
+						revoked_ksv_cnt);
+	else if (is_srm_version_hdcp2(buf))
+		return drm_hdcp_parse_hdcp2_srm(buf, count, revoked_ksv_list,
+						revoked_ksv_cnt);
+	else
+		return -EINVAL;
+}
+
+static int drm_hdcp_request_srm(struct drm_device *drm_dev,
+				u8 **revoked_ksv_list, u32 *revoked_ksv_cnt)
+{
+	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) {
+		*revoked_ksv_cnt = 0;
+		*revoked_ksv_list = NULL;
+		ret = 0;
+		goto exit;
+	}
+
+	if (fw->size && fw->data)
+		ret = drm_hdcp_srm_update(fw->data, fw->size, revoked_ksv_list,
+					  revoked_ksv_cnt);
+
+exit:
+	release_firmware(fw);
+	return ret;
+}
+
+/**
+ * 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:
+ * Count of the revoked KSVs or -ve error number in case of the failure.
+ */
+int drm_hdcp_check_ksvs_revoked(struct drm_device *drm_dev, u8 *ksvs,
+				u32 ksv_count)
+{
+	u32 revoked_ksv_cnt = 0, i, j;
+	u8 *revoked_ksv_list = NULL;
+	int ret = 0;
+
+	ret = drm_hdcp_request_srm(drm_dev, &revoked_ksv_list,
+				   &revoked_ksv_cnt);
+	if (ret)
+		return ret;
+
+	/* revoked_ksv_cnt will be zero when above function failed */
+	for (i = 0; i < revoked_ksv_cnt; i++)
+		for  (j = 0; j < ksv_count; j++)
+			if (!memcmp(&ksvs[j * DRM_HDCP_KSV_LEN],
+				    &revoked_ksv_list[i * DRM_HDCP_KSV_LEN],
+				    DRM_HDCP_KSV_LEN)) {
+				DRM_DEBUG("Revoked KSV is ");
+				drm_hdcp_print_ksv(&ksvs[j * DRM_HDCP_KSV_LEN]);
+				ret++;
+			}
+
+	kfree(revoked_ksv_list);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(drm_hdcp_check_ksvs_revoked);
+
+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);