Commit f5f5fa73 authored by Sergey Senozhatsky's avatar Sergey Senozhatsky Committed by Mauro Carvalho Chehab
Browse files

media: videobuf2: handle V4L2 buffer cache flags 



Set video buffer cache management flags corresponding to V4L2 cache
flags.

Both ->prepare() and ->finish() cache management hints should be
passed during this stage (buffer preparation), because there is
no other way for user-space to tell V4L2 to avoid ->finish() cache
flush.

Signed-off-by: default avatarSergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: default avatarHans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
parent 6d219986

drivers/media/common/videobuf2/videobuf2-v4l2.c

+48 −0
Original line number Diff line number Diff line
@@ -337,6 +337,53 @@ static int vb2_fill_vb2_v4l2_buffer(struct vb2_buffer *vb, struct v4l2_buffer *b 
	return 0;

}



static void set_buffer_cache_hints(struct vb2_queue *q,

				   struct vb2_buffer *vb,

				   struct v4l2_buffer *b)

{

	/*

	 * DMA exporter should take care of cache syncs, so we can avoid

	 * explicit ->prepare()/->finish() syncs. For other ->memory types

	 * we always need ->prepare() or/and ->finish() cache sync.

	 */

	if (q->memory == VB2_MEMORY_DMABUF) {

		vb->need_cache_sync_on_finish = 0;

		vb->need_cache_sync_on_prepare = 0;

		return;

	}



	/*

	 * Cache sync/invalidation flags are set by default in order to

	 * preserve existing behaviour for old apps/drivers.

	 */

	vb->need_cache_sync_on_prepare = 1;

	vb->need_cache_sync_on_finish = 1;



	if (!vb2_queue_allows_cache_hints(q)) {

		/*

		 * Clear buffer cache flags if queue does not support user

		 * space hints. That's to indicate to userspace that these

		 * flags won't work.

		 */

		b->flags &= ~V4L2_BUF_FLAG_NO_CACHE_INVALIDATE;

		b->flags &= ~V4L2_BUF_FLAG_NO_CACHE_CLEAN;

		return;

	}



	/*

	 * ->finish() cache sync can be avoided when queue direction is

	 * TO_DEVICE.

	 */

	if (q->dma_dir == DMA_TO_DEVICE)

		vb->need_cache_sync_on_finish = 0;



	if (b->flags & V4L2_BUF_FLAG_NO_CACHE_INVALIDATE)

		vb->need_cache_sync_on_finish = 0;



	if (b->flags & V4L2_BUF_FLAG_NO_CACHE_CLEAN)

		vb->need_cache_sync_on_prepare = 0;

}



static int vb2_queue_or_prepare_buf(struct vb2_queue *q, struct media_device *mdev,

				    struct v4l2_buffer *b, bool is_prepare,

				    struct media_request **p_req)
@@ -381,6 +428,7 @@ static int vb2_queue_or_prepare_buf(struct vb2_queue *q, struct media_device *md 
	}



	if (!vb->prepared) {

		set_buffer_cache_hints(q, vb, b);

		/* Copy relevant information provided by the userspace */

		memset(vbuf->planes, 0,

		       sizeof(vbuf->planes[0]) * vb->num_planes);

include/media/videobuf2-core.h

+11 −0
Original line number Diff line number Diff line
@@ -635,6 +635,17 @@ struct vb2_queue { 
#endif

};



/**

 * vb2_queue_allows_cache_hints() - Return true if the queue allows cache

 * and memory consistency hints.

 *

 * @q:		pointer to &struct vb2_queue with videobuf2 queue

 */

static inline bool vb2_queue_allows_cache_hints(struct vb2_queue *q)

{

	return q->allow_cache_hints && q->memory == VB2_MEMORY_MMAP;

}



/**

 * vb2_plane_vaddr() - Return a kernel virtual address of a given plane.

 * @vb:		pointer to &struct vb2_buffer to which the plane in