Add helpers to run the new media_pipeline_started() and
media_pipeline_stopped() functions. The helpers iterate over the
entities in the pipeline and count the number of video devices and
compare that to the pipeline's start_count() before acting. This
allows us to only run the media pipeline callbacks in the event that
the pipeline has had video_pipeline_start() called for each video
device.
Signed-off-by: Daniel Scally <dan.scally@xxxxxxxxxxxxxxxx>
---
We could take this further perhaps and include the equivalent routine
in video_device_pipeline[_alloc]_start()...if none of the entities
involved have .pipeline_started() or .pipeline_stopped() operations it
should be harmless, but I'm a bit reluctant to force the choice to run
those operations on users.
Changes in v2:
- Adapted now media_pipeline_for_each_entity() takes an iter
variable
- Fixed the Return: section of the kerneldoc comments
---
drivers/media/v4l2-core/v4l2-dev.c | 57 ++++++++++++++++++++++++++++++++++++++
include/media/v4l2-dev.h | 36 ++++++++++++++++++++++++
2 files changed, 93 insertions(+)
diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
index c369235113d98ae26c30a1aa386e7d60d541a66e..f3309f8349664f7296a95216a40dd9d9baae8d9e 100644
--- a/drivers/media/v4l2-core/v4l2-dev.c
+++ b/drivers/media/v4l2-core/v4l2-dev.c
@@ -1200,6 +1200,63 @@ struct media_pipeline *video_device_pipeline(struct video_device *vdev)
}
EXPORT_SYMBOL_GPL(video_device_pipeline);
+static int __video_device_pipeline_started(struct media_pipeline *pipe)
+{
+ struct media_pipeline_entity_iter iter;
+ unsigned int n_video_devices = 0;
+ struct media_entity *entity;
+ int ret;
+
+ ret = media_pipeline_entity_iter_init(pipe, &iter);
+ if (ret)
+ return ret;
+
+ media_pipeline_for_each_entity(pipe, &iter, entity) {
+ if (entity->obj_type == MEDIA_ENTITY_TYPE_VIDEO_DEVICE)
+ n_video_devices++;
+ }
+
+ media_pipeline_entity_iter_cleanup(&iter);
+
+ return n_video_devices - pipe->start_count;
+}
+
+int video_device_pipeline_started(struct video_device *vdev)
+{
+ struct media_pipeline *pipe;
+ int ret;
+
+ pipe = video_device_pipeline(vdev);
+ if (!pipe)
+ return -ENODEV;
+
+ ret = __video_device_pipeline_started(pipe);
+ if (ret)
+ return ret;
+
+ return media_pipeline_started(pipe);
+}
+EXPORT_SYMBOL_GPL(video_device_pipeline_started);
+
+int video_device_pipeline_stopped(struct video_device *vdev)
+{
+ struct media_pipeline *pipe;
+ int ret;
+
+ pipe = video_device_pipeline(vdev);
+ if (!pipe)
+ return -ENODEV;
+
+ ret = __video_device_pipeline_started(pipe);
+ if (ret)
+ return ret;
+
+ media_pipeline_stopped(pipe);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(video_device_pipeline_stopped);
+
#endif /* CONFIG_MEDIA_CONTROLLER */
/*
diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h
index 1b6222fab24eda96cbe459b435431c01f7259366..26b4a491024701ef47320aec6a1a680149ba4fc3 100644
--- a/include/media/v4l2-dev.h
+++ b/include/media/v4l2-dev.h
@@ -654,6 +654,42 @@ __must_check int video_device_pipeline_alloc_start(struct video_device *vdev);
*/
struct media_pipeline *video_device_pipeline(struct video_device *vdev);
+/**
+ * video_device_pipeline_started - Run the pipeline_started() entity operation
+ * for a fully-started media pipeline
+ * @vdev: A video device that's part of the pipeline
+ *
+ * This function checks whether all MEDIA_ENTITY_TYPE_VIDEO_DEVICE entities
+ * connected to a given video device through enabled links have been marked as
+ * streaming through the use of video_device_pipeline_start() or one of its
+ * equivalent functions. If so, media_pipeline_started() is called to inform
+ * entities in the pipeline of that fact. The intention is to provide drivers
+ * with a shortcut for checking whether their pipeline is fully ready to start
+ * processing data.
+ *
+ * Return: The number of video devices in the pipeline remaining to be started,
+ * or a negative error number on failure.
+ */
+int video_device_pipeline_started(struct video_device *vdev);
+
+/**
+ * video_device_pipeline_stopped - Run the pipeline_stopped() entity operation
+ * for a fully-started media pipeline
+ * @vdev: A video device that's part of the pipeline
+ *
+ * This function checks whether all MEDIA_ENTITY_TYPE_VIDEO_DEVICE entities
+ * connected to a given video device through enabled links have been marked as
+ * streaming through the use of video_device_pipeline_start() or one of its
+ * equivalent functions. If so, media_pipeline_stopped() is called for each
+ * entity in the pipeline. The intention is to provide drivers with a shortcut
+ * for checking whether this video device is the first device in the pipeline
+ * to be stopped.
+ *
+ * Return: The number of video devices in the pipeline remaining to be started, or a
+ * negative error number on failure.
+ */
+int video_device_pipeline_stopped(struct video_device *vdev);
+
#endif /* CONFIG_MEDIA_CONTROLLER */
#endif /* _V4L2_DEV_H */
--
2.34.1
