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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: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
This commit is contained in:
Sergey Senozhatsky 2020-05-14 18:01:42 +02:00 committed by Mauro Carvalho Chehab
parent 6d2199868a
commit f5f5fa73fb
2 changed files with 59 additions and 0 deletions
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48
drivers/media/common/videobuf2/videobuf2-v4l2.c
View File

@ -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);

11
include/media/videobuf2-core.h
View File

@ -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