drm/i915/hdcp: Add new remote capability check shim function

Create a remote HDCP capability shim function which can read the
remote monitor HDCP capability when in MST configuration.

--v2
-Add an assertion to make sure only mst encoder call this remote_cap
function [Ankit]

--v3
-rename remote_hdcp_cap to remote_hdcp_capability [Jani]

--v4
-fix hdcp2_prerequisite check condition
-Move intel_dp_hdcp_get_remote_capability to dp_mst shim instead of
having it in dp shim [Ankit]

Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240226051017.1652970-2-suraj.kandpal@intel.com

drivers/gpu/drm/i915/display/intel_display_types.h

@@ -531,6 +531,10 @@ struct intel_hdcp_shim {
 	/* HDCP2.2 Link Integrity Check */
 	int (*check_2_2_link)(struct intel_digital_port *dig_port,
 			      struct intel_connector *connector);
+
+	/* HDCP remote sink cap */
+	int (*get_remote_hdcp_capability)(struct intel_connector *connector,
+					  bool *hdcp_capable, bool *hdcp2_capable);
 };
 
 struct intel_hdcp {

drivers/gpu/drm/i915/display/intel_dp_hdcp.c

@@ -672,6 +672,32 @@ int intel_dp_hdcp2_get_capability(struct intel_connector *connector,
 	return _intel_dp_hdcp2_get_capability(aux, capable);
 }
 
+static
+int intel_dp_hdcp_get_remote_capability(struct intel_connector *connector,
+					bool *hdcp_capable,
+					bool *hdcp2_capable)
+{
+	struct drm_i915_private *i915 = to_i915(connector->base.dev);
+	struct drm_dp_aux *aux = &connector->port->aux;
+	u8 bcaps;
+	int ret;
+
+	if (!intel_encoder_is_mst(connector->encoder))
+		return -EINVAL;
+
+	ret =  _intel_dp_hdcp2_get_capability(aux, hdcp2_capable);
+	if (ret)
+		return ret;
+
+	ret = intel_dp_hdcp_read_bcaps(aux, i915, &bcaps);
+	if (ret)
+		return ret;
+
+	*hdcp_capable = bcaps & DP_BCAPS_HDCP_CAPABLE;
+
+	return 0;
+}
+
 static const struct intel_hdcp_shim intel_dp_hdcp_shim = {
 	.write_an_aksv = intel_dp_hdcp_write_an_aksv,
 	.read_bksv = intel_dp_hdcp_read_bksv,
@@ -820,6 +846,7 @@ static const struct intel_hdcp_shim intel_dp_mst_hdcp_shim = {
 	.stream_2_2_encryption = intel_dp_mst_hdcp2_stream_encryption,
 	.check_2_2_link = intel_dp_mst_hdcp2_check_link,
 	.hdcp_2_2_get_capability = intel_dp_hdcp2_get_capability,
+	.get_remote_hdcp_capability = intel_dp_hdcp_get_remote_capability,
 	.protocol = HDCP_PROTOCOL_DP,
 };
 

drivers/gpu/drm/i915/display/intel_hdcp.c

@@ -205,6 +205,22 @@ bool intel_hdcp2_get_capability(struct intel_connector *connector)
 	return capable;
 }
 
+void intel_hdcp_get_remote_capability(struct intel_connector *connector,
+				      bool *hdcp_capable,
+				      bool *hdcp2_capable)
+{
+	struct intel_hdcp *hdcp = &connector->hdcp;
+
+	if (!hdcp->shim->get_remote_hdcp_capability)
+		return;
+
+	hdcp->shim->get_remote_hdcp_capability(connector, hdcp_capable,
+					       hdcp2_capable);
+
+	if (!intel_hdcp2_prerequisite(connector))
+		*hdcp2_capable = false;
+}
+
 static bool intel_hdcp_in_use(struct drm_i915_private *i915,
 			      enum transcoder cpu_transcoder, enum port port)
 {

drivers/gpu/drm/i915/display/intel_hdcp.h

@@ -40,6 +40,9 @@ void intel_hdcp_update_pipe(struct intel_atomic_state *state,
 bool is_hdcp_supported(struct drm_i915_private *i915, enum port port);
 bool intel_hdcp_get_capability(struct intel_connector *connector);
 bool intel_hdcp2_get_capability(struct intel_connector *connector);
+void intel_hdcp_get_remote_capability(struct intel_connector *connector,
+				      bool *hdcp_capable,
+				      bool *hdcp2_capable);
 void intel_hdcp_component_init(struct drm_i915_private *i915);
 void intel_hdcp_component_fini(struct drm_i915_private *i915);
 void intel_hdcp_cleanup(struct intel_connector *connector);