[PATCH v8 04/13] [media] vb2: add is_unordered callback for drivers

From: Gustavo Padovan
Date: Fri Mar 09 2018 - 12:52:26 EST


From: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxx>

Explicit synchronization benefits a lot from ordered queues, they fit
better in a pipeline with DRM for example so create a opt-in way for
drivers notify videobuf2 that the queue is unordered.

Drivers don't need implement it if the queue is ordered.

v2: - improve comments for is_unordered flag (Hans)

v3: - make it bool (Hans)
- create vb2_ops_set_unordered() helper

Signed-off-by: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxx>
---
drivers/media/common/videobuf2/videobuf2-v4l2.c | 6 ++++++
include/media/videobuf2-core.h | 6 ++++++
include/media/videobuf2-v4l2.h | 10 ++++++++++
3 files changed, 22 insertions(+)

diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
index 886a2d8d5c6c..68291ba8632d 100644
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
@@ -961,6 +961,12 @@ void vb2_ops_wait_finish(struct vb2_queue *vq)
}
EXPORT_SYMBOL_GPL(vb2_ops_wait_finish);

+bool vb2_ops_set_unordered(struct vb2_queue *q)
+{
+ return true;
+}
+EXPORT_SYMBOL_GPL(vb2_ops_set_unordered);
+
MODULE_DESCRIPTION("Driver helper framework for Video for Linux 2");
MODULE_AUTHOR("Pawel Osciak <pawel@xxxxxxxxxx>, Marek Szyprowski");
MODULE_LICENSE("GPL");
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index 5b6c541e4e1b..46a9e674f7e1 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -370,6 +370,10 @@ struct vb2_buffer {
* callback by calling vb2_buffer_done() with either
* %VB2_BUF_STATE_DONE or %VB2_BUF_STATE_ERROR; may use
* vb2_wait_for_all_buffers() function
+ * @is_unordered: tell if the queue is unordered, i.e. buffers can be
+ * dequeued in a different order from how they were queued.
+ * The default is assumed to be ordered and this function
+ * only needs to be implemented for unordered queues.
* @buf_queue: passes buffer vb to the driver; driver may start
* hardware operation on this buffer; driver should give
* the buffer back by calling vb2_buffer_done() function;
@@ -393,6 +397,7 @@ struct vb2_ops {

int (*start_streaming)(struct vb2_queue *q, unsigned int count);
void (*stop_streaming)(struct vb2_queue *q);
+ bool (*is_unordered)(struct vb2_queue *q);

void (*buf_queue)(struct vb2_buffer *vb);
};
@@ -566,6 +571,7 @@ struct vb2_queue {
u32 cnt_wait_finish;
u32 cnt_start_streaming;
u32 cnt_stop_streaming;
+ u32 cnt_is_unordered;
#endif
};

diff --git a/include/media/videobuf2-v4l2.h b/include/media/videobuf2-v4l2.h
index 3d5e2d739f05..9de3c887c875 100644
--- a/include/media/videobuf2-v4l2.h
+++ b/include/media/videobuf2-v4l2.h
@@ -291,4 +291,14 @@ void vb2_ops_wait_prepare(struct vb2_queue *vq);
*/
void vb2_ops_wait_finish(struct vb2_queue *vq);

+/**
+ * vb2_ops_set_unordered - helper function to mark queue as unordered
+ *
+ * @vq: pointer to &struct vb2_queue
+ *
+ * This helper just return true to notify that the driver can't deal with
+ * ordered queues.
+ */
+bool vb2_ops_set_unordered(struct vb2_queue *q);
+
#endif /* _MEDIA_VIDEOBUF2_V4L2_H */
--
2.14.3