Hi Thierry,
On Thu, Oct 20, 2016 at 10:56:04AM +0200, Thierry Escande wrote:
> From: Pawel Osciak <posciak@xxxxxxxxxxxx>
>
> When this flag is set for CAPTURE queues by the driver on calling
> vb2_queue_init(), it forces the buffers on the queue to be
> allocated/mapped with DMA_BIDIRECTIONAL direction flag instead of
> DMA_FROM_DEVICE. This allows the device not only to write to the
> buffers, but also read out from them. This may be useful e.g. for codec
> hardware which may be using CAPTURE buffers as reference to decode
> other buffers.
>
> This flag is ignored for OUTPUT queues as we don't want to allow HW to
> be able to write to OUTPUT buffers.
>
> Signed-off-by: Pawel Osciak <posciak@xxxxxxxxxxxx>
> Tested-by: Pawel Osciak <posciak@xxxxxxxxxxxx>
> Signed-off-by: Thierry Escande <thierry.escande@xxxxxxxxxxxxx>
> ---
>
> Changes since v1:
> - Renamed use_dma_bidirectional field as capture_dma_bidirectional
> - Added a VB2_DMA_DIR() macro
>
> Changes since v2:
> - Get rid of dma_dir field and therefore squashed the previous patch
>
> drivers/media/v4l2-core/videobuf2-core.c | 9 +++------
> include/media/videobuf2-core.h | 15 +++++++++++++++
> 2 files changed, 18 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
> index 21900202..22d6105 100644
> --- a/drivers/media/v4l2-core/videobuf2-core.c
> +++ b/drivers/media/v4l2-core/videobuf2-core.c
> @@ -194,8 +194,7 @@ static void __enqueue_in_driver(struct vb2_buffer *vb);
> static int __vb2_buf_mem_alloc(struct vb2_buffer *vb)
> {
> struct vb2_queue *q = vb->vb2_queue;
> - enum dma_data_direction dma_dir =
> - q->is_output ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
> + enum dma_data_direction dma_dir = VB2_DMA_DIR(q);
> void *mem_priv;
> int plane;
> int ret = -ENOMEM;
> @@ -978,8 +977,7 @@ static int __qbuf_userptr(struct vb2_buffer *vb, const void *pb)
> void *mem_priv;
> unsigned int plane;
> int ret = 0;
> - enum dma_data_direction dma_dir =
> - q->is_output ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
> + enum dma_data_direction dma_dir = VB2_DMA_DIR(q);
> bool reacquired = vb->planes[0].mem_priv == NULL;
>
> memset(planes, 0, sizeof(planes[0]) * vb->num_planes);
> @@ -1096,8 +1094,7 @@ static int __qbuf_dmabuf(struct vb2_buffer *vb, const void *pb)
> void *mem_priv;
> unsigned int plane;
> int ret = 0;
> - enum dma_data_direction dma_dir =
> - q->is_output ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
> + enum dma_data_direction dma_dir = VB2_DMA_DIR(q);
> bool reacquired = vb->planes[0].mem_priv == NULL;
>
> memset(planes, 0, sizeof(planes[0]) * vb->num_planes);
> diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
> index ac5898a..631f08b 100644
> --- a/include/media/videobuf2-core.h
> +++ b/include/media/videobuf2-core.h
> @@ -433,6 +433,9 @@ struct vb2_buf_ops {
> * @quirk_poll_must_check_waiting_for_buffers: Return POLLERR at poll when QBUF
> * has not been called. This is a vb1 idiom that has been adopted
> * also by vb2.
> + * @capture_dma_bidirectional: use DMA_BIDIRECTIONAL for CAPTURE buffers; this
> + * allows HW to read from the CAPTURE buffers in
> + * addition to writing; ignored for OUTPUT queues.
> * @lock: pointer to a mutex that protects the vb2_queue struct. The
> * driver can set this to a mutex to let the v4l2 core serialize
> * the queuing ioctls. If the driver wants to handle locking
> @@ -499,6 +502,7 @@ struct vb2_queue {
> unsigned fileio_write_immediately:1;
> unsigned allow_zero_bytesused:1;
> unsigned quirk_poll_must_check_waiting_for_buffers:1;
> + unsigned capture_dma_bidirectional:1;
>
> struct mutex *lock;
> void *owner;
> @@ -554,6 +558,17 @@ struct vb2_queue {
> #endif
> };
>
> +/*
> + * Return the corresponding DMA direction given the vb2_queue type (capture or
> + * output). returns DMA_BIRECTIONAL for capture buffers if the vb2_queue field
DMA_BIDIRECTIONAL
With that fixed,
Acked-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> + * capture_dma_bidirectional is set by the driver.
> + */
> +#define VB2_DMA_DIR(q) (V4L2_TYPE_IS_OUTPUT((q)->type) \
> + ? DMA_TO_DEVICE \
> + : (q)->capture_dma_bidirectional \
> + ? DMA_BIDIRECTIONAL \
> + : DMA_FROM_DEVICE)
> +
> /**
> * vb2_plane_vaddr() - Return a kernel virtual address of a given plane
> * @vb: vb2_buffer to which the plane in question belongs to
--
Sakari Ailus
e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx
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