[v5,4/4] media: camss: sm8250: Pipeline starting and stopping for multiple virtual channels

Commit Message

Milen Mitkov (Consultant) Nov. 28, 2022, 2:42 p.m. UTC

From: Milen Mitkov <[e-mail]>

Use the multistream series function video_device_pipeline_alloc_start
to allows multiple clients of the same pipeline.

If the VFE entity is used by another instance of the pipeline,
the pipeline won't be stopped. This allows for stopping and starting
streams at any point without disrupting the other running streams.

Signed-off-by: Milen Mitkov <[e-mail]>
Reviewed-by: Robert Foss <[e-mail]>
Tested-by: Bryan O'Donoghue <[e-mail]>
Acked-by: Robert Foss <[e-mail]>
---
 .../media/platform/qcom/camss/camss-video.c   | 21 ++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

Patch

diff --git a/drivers/media/platform/qcom/camss/camss-video.c b/drivers/media/platform/qcom/camss/camss-video.c
index 41deda232e4a..12ac7d4d755e 100644
--- a/drivers/media/platform/qcom/camss/camss-video.c
+++ b/drivers/media/platform/qcom/camss/camss-video.c
@@ -351,6 +351,7 @@  static int video_get_subdev_format(struct camss_video *video,
 	if (subdev == NULL)
 		return -EPIPE;
 
+	memset(&fmt, 0, sizeof(fmt));
 	fmt.pad = pad;
 	fmt.which = V4L2_SUBDEV_FORMAT_ACTIVE;
 
@@ -493,9 +494,11 @@  static int video_start_streaming(struct vb2_queue *q, unsigned int count)
 	struct v4l2_subdev *subdev;
 	int ret;
 
-	ret = video_device_pipeline_start(vdev, &video->pipe);
-	if (ret < 0)
+	ret = video_device_pipeline_alloc_start(vdev);
+	if (ret < 0) {
+		dev_err(video->camss->dev, "Failed to start media pipeline: %d\n", ret);
 		goto flush_buffers;
+	}
 
 	ret = video_check_format(video);
 	if (ret < 0)
@@ -537,6 +540,7 @@  static void video_stop_streaming(struct vb2_queue *q)
 	struct media_entity *entity;
 	struct media_pad *pad;
 	struct v4l2_subdev *subdev;
+	int ret;
 
 	entity = &vdev->entity;
 	while (1) {
@@ -551,7 +555,18 @@  static void video_stop_streaming(struct vb2_queue *q)
 		entity = pad->entity;
 		subdev = media_entity_to_v4l2_subdev(entity);
 
-		v4l2_subdev_call(subdev, video, s_stream, 0);
+		ret = v4l2_subdev_call(subdev, video, s_stream, 0);
+
+		if (entity->use_count > 1) {
+			/* Don't stop if other instances of the pipeline are still running */
+			dev_dbg(video->camss->dev, "Video pipeline still used, don't stop streaming.\n");
+			return;
+		}
+
+		if (ret) {
+			dev_err(video->camss->dev, "Video pipeline stop failed: %d\n", ret);
+			return;
+		}
 	}
 
 	video_device_pipeline_stop(vdev);