drm/radeon/audio: write audio/video latency info for DCE6/8

Needed by the hda driver to properly set up synchronization
on the audio side.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
diff --git a/drivers/gpu/drm/radeon/dce6_afmt.c b/drivers/gpu/drm/radeon/dce6_afmt.c
index 85a69d2..5929056 100644
--- a/drivers/gpu/drm/radeon/dce6_afmt.c
+++ b/drivers/gpu/drm/radeon/dce6_afmt.c
@@ -102,6 +102,49 @@
 	       AFMT_AUDIO_SRC_SELECT(dig->afmt->pin->id));
 }
 
+void dce6_afmt_write_latency_fields(struct drm_encoder *encoder,
+				    struct drm_display_mode *mode)
+{
+	struct radeon_device *rdev = encoder->dev->dev_private;
+	struct radeon_encoder *radeon_encoder = to_radeon_encoder(encoder);
+	struct radeon_encoder_atom_dig *dig = radeon_encoder->enc_priv;
+	struct drm_connector *connector;
+	struct radeon_connector *radeon_connector = NULL;
+	u32 tmp = 0, offset;
+
+	if (!dig->afmt->pin)
+		return;
+
+	offset = dig->afmt->pin->offset;
+
+	list_for_each_entry(connector, &encoder->dev->mode_config.connector_list, head) {
+		if (connector->encoder == encoder) {
+			radeon_connector = to_radeon_connector(connector);
+			break;
+		}
+	}
+
+	if (!radeon_connector) {
+		DRM_ERROR("Couldn't find encoder's connector\n");
+		return;
+	}
+
+	if (mode->flags & DRM_MODE_FLAG_INTERLACE) {
+		if (connector->latency_present[1])
+			tmp = VIDEO_LIPSYNC(connector->video_latency[1]) |
+				AUDIO_LIPSYNC(connector->audio_latency[1]);
+		else
+			tmp = VIDEO_LIPSYNC(255) | AUDIO_LIPSYNC(255);
+	} else {
+		if (connector->latency_present[0])
+			tmp = VIDEO_LIPSYNC(connector->video_latency[0]) |
+				AUDIO_LIPSYNC(connector->audio_latency[0]);
+		else
+			tmp = VIDEO_LIPSYNC(255) | AUDIO_LIPSYNC(255);
+	}
+	WREG32_ENDPOINT(offset, AZ_F0_CODEC_PIN_CONTROL_RESPONSE_LIPSYNC, tmp);
+}
+
 void dce6_afmt_write_speaker_allocation(struct drm_encoder *encoder)
 {
 	struct radeon_device *rdev = encoder->dev->dev_private;