[PATCH v3 06/10] drm: Add CP downstream_info property

[Ramalingam C <ramalingam.c@intel.com>]

This patch adds a optional CP downstream info blob property to the
connectors. This enables the Userspace to read the information of HDCP
authenticated downstream topology.

Driver will updated this blob with all downstream information at the
end of the authentication.

In case userspace configures this platform as repeater, then this
information is needed for the authentication with upstream HDCP
transmitter.

v2:
  s/cp_downstream/content_protection_downstream [daniel]
v3:
  s/content_protection_downstream/hdcp_topology [daniel]

Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
---
 drivers/gpu/drm/drm_atomic_uapi.c |  4 ++
 drivers/gpu/drm/drm_connector.c   | 86 +++++++++++++++++++++++++++++++
 include/drm/drm_connector.h       | 12 +++++
 include/uapi/drm/drm_mode.h       | 27 ++++++++++
 4 files changed, 129 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
index 857ca6fa6fd0..4246e8988c29 100644
--- a/drivers/gpu/drm/drm_atomic_uapi.c
+++ b/drivers/gpu/drm/drm_atomic_uapi.c
@@ -826,6 +826,10 @@ drm_atomic_connector_get_property(struct drm_connector *connector,
 		*val = state->content_protection;
 	} else if (property == connector->hdcp_content_type_property) {
 		*val = state->hdcp_content_type;
+	} else if (property ==
+		   connector->hdcp_topology_property) {
+		*val = connector->hdcp_topology_blob_ptr ?
+			connector->hdcp_topology_blob_ptr->base.id : 0;
 	} else if (property == config->writeback_fb_id_property) {
 		/* Writeback framebuffer is one-shot, write and forget */
 		*val = 0;
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index ff61c3208307..0de8b441a449 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -246,6 +246,7 @@ int drm_connector_init(struct drm_device *dev,
 	mutex_init(&connector->mutex);
 	connector->edid_blob_ptr = NULL;
 	connector->tile_blob_ptr = NULL;
+	connector->hdcp_topology_blob_ptr = NULL;
 	connector->status = connector_status_unknown;
 	connector->display_info.panel_orientation =
 		DRM_MODE_PANEL_ORIENTATION_UNKNOWN;
@@ -986,6 +987,25 @@ DRM_ENUM_NAME_FN(drm_get_hdcp_content_type_name,
  *	authentication process. If content type is changed when
  *	content_protection is not UNDESIRED, then kernel will disable the HDCP
  *	and re-enable with new type in the same atomic commit
+ * HDCP Topology:
+ *	This blob property is used to pass the HDCP downstream topology details
+ *	of a HDCP encrypted connector, from kernel to userspace.
+ *	This provides all required information to userspace, so that userspace
+ *	can implement the HDCP repeater using the kernel as downstream ports of
+ *	the repeater. as illustrated below:
+ *
+ *                          HDCP Repeaters
+ * +--------------------------------------------------------------+
+ * |                                                              |
+ * |                               |                              |
+ * |   Userspace HDCP Receiver  +----->    KMD HDCP transmitters  |
+ * |      (Upstream Port)      <------+     (Downstream Ports)    |
+ * |                               |                              |
+ * |                                                              |
+ * +--------------------------------------------------------------+
+ *
+ *	Kernel will populate this blob only when the HDCP authentication is
+ *	successful.
  *
  * max bpc:
  *	This range property is used by userspace to limit the bit depth. When
@@ -1614,6 +1634,72 @@ drm_connector_attach_hdcp_content_type_property(struct drm_connector *
 }
 EXPORT_SYMBOL(drm_connector_attach_hdcp_content_type_property);
 
+/**
+ * drm_connector_attach_hdcp_topology_property - attach hdcp topology property
+ *
+ * @connector: connector to attach hdcp topology property with.
+ *
+ * This is used to add support for hdcp topology support on select connectors.
+ * When Intel platform is configured as repeater, this downstream info is used
+ * by userspace, to complete the repeater authentication of HDCP specification
+ * with upstream HDCP transmitter.
+ *
+ * The blob_id of the hdcp topology info will be set to
+ * &drm_connector_state.hdcp_topology
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int drm_connector_attach_hdcp_topology_property(struct drm_connector *connector)
+{
+	struct drm_device *dev = connector->dev;
+	struct drm_property *prop;
+
+	prop = drm_property_create(dev, DRM_MODE_PROP_BLOB |
+				   DRM_MODE_PROP_IMMUTABLE,
+				   "HDCP Topology", 0);
+	if (!prop)
+		return -ENOMEM;
+
+	drm_object_attach_property(&connector->base, prop, 0);
+
+	connector->hdcp_topology_property = prop;
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_connector_attach_hdcp_topology_property);
+
+/**
+ * drm_connector_update_hdcp_topology_property - update the hdcp topology
+ * property of a connector
+ * @connector: drm connector, the topology is associated to
+ * @hdcp_topology_info: new content for the blob of hdcp_topology property
+ *
+ * This function creates a new blob modeset object and assigns its id to the
+ * connector's hdcp_topology property.
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int
+drm_connector_update_hdcp_topology_property(struct drm_connector *connector,
+					const struct hdcp_topology_info *info)
+{
+	struct drm_device *dev = connector->dev;
+	int ret;
+
+	if (!info)
+		return -EINVAL;
+
+	ret = drm_property_replace_global_blob(dev,
+			&connector->hdcp_topology_blob_ptr,
+			sizeof(struct hdcp_topology_info),
+			info, &connector->base,
+			connector->hdcp_topology_property);
+	return ret;
+}
+EXPORT_SYMBOL(drm_connector_update_hdcp_topology_property);
+
 /**
  * drm_mode_create_aspect_ratio_property - create aspect ratio property
  * @dev: DRM device
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index f0830985367f..c016a0bcedac 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -1047,6 +1047,13 @@ struct drm_connector {
 	 */
 	struct drm_property *hdcp_content_type_property;
 
+	/**
+	 * @hdcp_topology_property: DRM BLOB property for hdcp downstream
+	 * topology information.
+	 */
+	struct drm_property *hdcp_topology_property;
+	struct drm_property_blob *hdcp_topology_blob_ptr;
+
 	/**
 	 * @path_blob_ptr:
 	 *
@@ -1324,6 +1331,11 @@ int drm_connector_attach_content_protection_property(
 		struct drm_connector *connector);
 int drm_connector_attach_hdcp_content_type_property(
 		struct drm_connector *connector);
+int drm_connector_attach_hdcp_topology_property(
+		struct drm_connector *connector);
+int drm_connector_update_hdcp_topology_property(
+		struct drm_connector *connector,
+		const struct hdcp_topology_info *info);
 int drm_mode_create_aspect_ratio_property(struct drm_device *dev);
 int drm_mode_create_colorspace_property(struct drm_connector *connector);
 int drm_mode_create_content_type_property(struct drm_device *dev);
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index 44412e8b77cd..03d3aa2b1a49 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -214,6 +214,33 @@ extern "C" {
 #define DRM_MODE_HDCP_CONTENT_TYPE0		0
 #define DRM_MODE_HDCP_CONTENT_TYPE1		1
 
+#define DRM_MODE_HDCP_KSV_LEN			5
+#define DRM_MODE_HDCP_MAX_DEVICE_CNT		127
+
+struct hdcp_topology_info {
+	/* KSV of immediate HDCP Sink. In Little-Endian Format. */
+	char bksv[DRM_MODE_HDCP_KSV_LEN];
+
+	/* Whether Immediate HDCP sink is a repeater? */
+	bool is_repeater;
+
+	/* Depth received from immediate downstream repeater */
+	__u8 depth;
+
+	/* Device count received from immediate downstream repeater */
+	__u32 device_count;
+
+	/*
+	 * Max buffer required to hold ksv list received from immediate
+	 * repeater. In this array first device_count * DRM_MODE_HDCP_KSV_LEN
+	 * will hold the valid ksv bytes.
+	 * If authentication specification is
+	 *	HDCP1.4 - each KSV's Bytes will be in Little-Endian format.
+	 *	HDCP2.2 - each KSV's Bytes will be in Big-Endian format.
+	 */
+	char ksv_list[DRM_MODE_HDCP_KSV_LEN * DRM_MODE_HDCP_MAX_DEVICE_CNT];
+};
+
 struct drm_mode_modeinfo {
 	__u32 clock;
 	__u16 hdisplay;
-- 
2.19.1

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