On 2/4/20 3:56 AM, Sergey Senozhatsky wrote:
> 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.
This should also be a comment in the code.
Regards,
Hans
>
> Change-Id: Ia0d9d72a8c2a9fe3264ac148f59201573289ed2c
> Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
> ---
> .../media/common/videobuf2/videobuf2-dma-sg.c | 22 +++++++++++++++++++
> 1 file changed, 22 insertions(+)
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-dma-sg.c b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
> index 6db60e9d5183..bfc99a0cb7b9 100644
> --- a/drivers/media/common/videobuf2/videobuf2-dma-sg.c
> +++ b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
> @@ -470,6 +470,26 @@ 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;
> @@ -488,6 +508,8 @@ 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,
>
