drm/amd/display: add HDCP caps debugfs

Add debugfs to get HDCP capability. This is also useful for
kms_content_protection igt test.

Use:
	cat /sys/kernel/debug/dri/0/DP-1/hdcp_sink_capability
	cat /sys/kernel/debug/dri/0/HDMI-A-1/hdcp_sink_capability
Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c

@@ -838,6 +838,44 @@ static int vrr_range_show(struct seq_file *m, void *data)
 	return 0;
 }
 
+#ifdef CONFIG_DRM_AMD_DC_HDCP
+/*
+ * Returns the HDCP capability of the Display (1.4 for now).
+ *
+ * NOTE* Not all HDMI displays report their HDCP caps even when they are capable.
+ * Since its rare for a display to not be HDCP 1.4 capable, we set HDMI as always capable.
+ *
+ * Example usage: cat /sys/kernel/debug/dri/0/DP-1/hdcp_sink_capability
+ *		or cat /sys/kernel/debug/dri/0/HDMI-A-1/hdcp_sink_capability
+ */
+static int hdcp_sink_capability_show(struct seq_file *m, void *data)
+{
+	struct drm_connector *connector = m->private;
+	struct amdgpu_dm_connector *aconnector = to_amdgpu_dm_connector(connector);
+	bool hdcp_cap, hdcp2_cap;
+
+	if (connector->status != connector_status_connected)
+		return -ENODEV;
+
+	seq_printf(m, "%s:%d HDCP version: ", connector->name, connector->base.id);
+
+	hdcp_cap = dc_link_is_hdcp14(aconnector->dc_link);
+	hdcp2_cap = dc_link_is_hdcp22(aconnector->dc_link);
+
+
+	if (hdcp_cap)
+		seq_printf(m, "%s ", "HDCP1.4");
+	if (hdcp2_cap)
+		seq_printf(m, "%s ", "HDCP2.2");
+
+	if (!hdcp_cap && !hdcp2_cap)
+		seq_printf(m, "%s ", "None");
+
+	seq_puts(m, "\n");
+
+	return 0;
+}
+#endif
 /* function description
  *
  * generic SDP message access for testing
@@ -964,6 +1002,9 @@ DEFINE_SHOW_ATTRIBUTE(dmub_fw_state);
 DEFINE_SHOW_ATTRIBUTE(dmub_tracebuffer);
 DEFINE_SHOW_ATTRIBUTE(output_bpc);
 DEFINE_SHOW_ATTRIBUTE(vrr_range);
+#ifdef CONFIG_DRM_AMD_DC_HDCP
+DEFINE_SHOW_ATTRIBUTE(hdcp_sink_capability);
+#endif
 
 static const struct file_operations dp_link_settings_debugfs_fops = {
 	.owner = THIS_MODULE,
@@ -1019,12 +1060,23 @@ static const struct {
 		{"test_pattern", &dp_phy_test_pattern_fops},
 		{"output_bpc", &output_bpc_fops},
 		{"vrr_range", &vrr_range_fops},
+#ifdef CONFIG_DRM_AMD_DC_HDCP
+		{"hdcp_sink_capability", &hdcp_sink_capability_fops},
+#endif
 		{"sdp_message", &sdp_message_fops},
 		{"aux_dpcd_address", &dp_dpcd_address_debugfs_fops},
 		{"aux_dpcd_size", &dp_dpcd_size_debugfs_fops},
 		{"aux_dpcd_data", &dp_dpcd_data_debugfs_fops}
 };
 
+#ifdef CONFIG_DRM_AMD_DC_HDCP
+static const struct {
+	char *name;
+	const struct file_operations *fops;
+} hdmi_debugfs_entries[] = {
+		{"hdcp_sink_capability", &hdcp_sink_capability_fops}
+};
+#endif
 /*
  * Force YUV420 output if available from the given mode
  */
@@ -1093,6 +1145,15 @@ void connector_debugfs_init(struct amdgpu_dm_connector *connector)
 	connector->debugfs_dpcd_address = 0;
 	connector->debugfs_dpcd_size = 0;
 
+#ifdef CONFIG_DRM_AMD_DC_HDCP
+	if (connector->base.connector_type == DRM_MODE_CONNECTOR_HDMIA) {
+		for (i = 0; i < ARRAY_SIZE(hdmi_debugfs_entries); i++) {
+			debugfs_create_file(hdmi_debugfs_entries[i].name,
+					    0644, dir, connector,
+					    hdmi_debugfs_entries[i].fops);
+		}
+	}
+#endif
 }
 
 /*

drivers/gpu/drm/amd/display/dc/core/dc_link.c

@@ -516,6 +516,53 @@ static void link_disconnect_remap(struct dc_sink *prev_sink, struct dc_link *lin
 }
 
 #if defined(CONFIG_DRM_AMD_DC_HDCP)
+bool dc_link_is_hdcp14(struct dc_link *link)
+{
+	bool ret = false;
+
+	switch (link->connector_signal)	{
+	case SIGNAL_TYPE_DISPLAY_PORT:
+	case SIGNAL_TYPE_DISPLAY_PORT_MST:
+		ret = link->hdcp_caps.bcaps.bits.HDCP_CAPABLE;
+		break;
+	case SIGNAL_TYPE_DVI_SINGLE_LINK:
+	case SIGNAL_TYPE_DVI_DUAL_LINK:
+	case SIGNAL_TYPE_HDMI_TYPE_A:
+	/* HDMI doesn't tell us its HDCP(1.4) capability, so assume to always be capable,
+	 * we can poll for bksv but some displays have an issue with this. Since its so rare
+	 * for a display to not be 1.4 capable, this assumtion is ok
+	 */
+		ret = true;
+		break;
+	default:
+		break;
+	}
+	return ret;
+}
+
+bool dc_link_is_hdcp22(struct dc_link *link)
+{
+	bool ret = false;
+
+	switch (link->connector_signal)	{
+	case SIGNAL_TYPE_DISPLAY_PORT:
+	case SIGNAL_TYPE_DISPLAY_PORT_MST:
+		ret = (link->hdcp_caps.bcaps.bits.HDCP_CAPABLE &&
+				link->hdcp_caps.rx_caps.fields.byte0.hdcp_capable &&
+				(link->hdcp_caps.rx_caps.fields.version == 0x2)) ? 1 : 0;
+		break;
+	case SIGNAL_TYPE_DVI_SINGLE_LINK:
+	case SIGNAL_TYPE_DVI_DUAL_LINK:
+	case SIGNAL_TYPE_HDMI_TYPE_A:
+		ret = (link->hdcp_caps.rx_caps.fields.version == 0x4) ? 1:0;
+		break;
+	default:
+		break;
+	}
+
+	return ret;
+}
+
 static void query_hdcp_capability(enum signal_type signal, struct dc_link *link)
 {
 	struct hdcp_protection_message msg22;

drivers/gpu/drm/amd/display/dc/dc_link.h

@@ -293,6 +293,10 @@ bool dc_link_detect_sink(struct dc_link *link, enum dc_connection_type *type);
  * DPCD access interfaces
  */
 
+#ifdef CONFIG_DRM_AMD_DC_HDCP
+bool dc_link_is_hdcp14(struct dc_link *link);
+bool dc_link_is_hdcp22(struct dc_link *link);
+#endif
 void dc_link_set_drive_settings(struct dc *dc,
 				struct link_training_settings *lt_settings,
 				const struct dc_link *link);