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media: videobuf2: add begin/end cpu_access callbacks to dma-sg

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Provide begin_cpu_access() and end_cpu_access() dma_buf_ops
callbacks for cache synchronisation on exported buffers.

V4L2_FLAG_MEMORY_NON_CONSISTENT has no effect on dma-sg buffers.
dma-sg allocates memory using the page allocator directly, so
there is no memory consistency guarantee.

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 18:01:50 +02:00 committed by Mauro Carvalho Chehab
parent d5adf1b0c2
commit d4db5eb57c
1 changed files with 30 additions and 0 deletions
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30
drivers/media/common/videobuf2/videobuf2-dma-sg.c
View file

@ -120,6 +120,12 @@ static void *vb2_dma_sg_alloc(struct device *dev, unsigned long dma_attrs,
buf->num_pages = size >> PAGE_SHIFT;
buf->dma_sgt = &buf->sg_table;
/*
* NOTE: dma-sg allocates memory using the page allocator directly, so
* there is no memory consistency guarantee, hence dma-sg ignores DMA
* attributes passed from the upper layer. That means that
* V4L2_FLAG_MEMORY_NON_CONSISTENT has no effect on dma-sg buffers.
*/
buf->pages = kvmalloc_array(buf->num_pages, sizeof(struct page *),
GFP_KERNEL | __GFP_ZERO);
if (!buf->pages)
@ -469,6 +475,28 @@ static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf)
vb2_dma_sg_put(dbuf->priv);
}
static int
vb2_dma_sg_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf,
enum dma_data_direction direction)
{
struct vb2_dma_sg_buf *buf = dbuf->priv;
struct sg_table *sgt = buf->dma_sgt;
dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
return 0;
}
static int
vb2_dma_sg_dmabuf_ops_end_cpu_access(struct dma_buf *dbuf,
enum dma_data_direction direction)
{
struct vb2_dma_sg_buf *buf = dbuf->priv;
struct sg_table *sgt = buf->dma_sgt;
dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
return 0;
}
static void *vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf)
{
struct vb2_dma_sg_buf *buf = dbuf->priv;
@ -487,6 +515,8 @@ static const struct dma_buf_ops vb2_dma_sg_dmabuf_ops = {
.detach = vb2_dma_sg_dmabuf_ops_detach,
.map_dma_buf = vb2_dma_sg_dmabuf_ops_map,
.unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap,
.begin_cpu_access = vb2_dma_sg_dmabuf_ops_begin_cpu_access,
.end_cpu_access = vb2_dma_sg_dmabuf_ops_end_cpu_access,
.vmap = vb2_dma_sg_dmabuf_ops_vmap,
.mmap = vb2_dma_sg_dmabuf_ops_mmap,
.release = vb2_dma_sg_dmabuf_ops_release,