Hi Hans,
Thank you for the patch.
On Friday 12 September 2014 14:59:52 Hans Verkuil wrote:
> From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
>
> This moves dma_(un)map_sg to the prepare/finish memops of
> videobuf2-dma-sg.c.
>
> Now that vb2-dma-sg will sync the buffers for you in the prepare/finish
> memops we can drop that from the drivers that use dma-sg.
>
> For the solo6x10 driver that was a bit more involved because it needs to
> copy JPEG or MPEG headers to the buffer before returning it to userspace,
> and that cannot be done in the old place since the buffer there is still
> setup for DMA access, not for CPU access. However, the buf_finish_for_cpu
> op is the ideal place to do this. By the time buf_finish_for_cpu is called
> the buffer is available for CPU access, so copying to the buffer is fine.
>
> Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> ---
> drivers/media/pci/cx23885/cx23885-417.c | 7 +---
> drivers/media/pci/cx23885/cx23885-core.c | 5 ---
> drivers/media/pci/cx23885/cx23885-dvb.c | 7 +---
> drivers/media/pci/cx23885/cx23885-vbi.c | 13 +------
> drivers/media/pci/cx23885/cx23885-video.c | 13 +------
> drivers/media/pci/saa7134/saa7134-empress.c | 1 -
> drivers/media/pci/saa7134/saa7134-ts.c | 16 --------
> drivers/media/pci/saa7134/saa7134-vbi.c | 15 --------
> drivers/media/pci/saa7134/saa7134-video.c | 15 --------
> drivers/media/pci/saa7134/saa7134.h | 1 -
> drivers/media/pci/solo6x10/solo6x10-v4l2-enc.c | 50 ++++++++++------------
> drivers/media/pci/tw68/tw68-video.c | 12 +-----
> drivers/media/platform/marvell-ccic/mcam-core.c | 18 +--------
> drivers/media/v4l2-core/videobuf2-dma-sg.c | 18 +++++++++
> 14 files changed, 51 insertions(+), 140 deletions(-)
[snip]
> diff --git a/drivers/media/v4l2-core/videobuf2-dma-sg.c
> b/drivers/media/v4l2-core/videobuf2-dma-sg.c index 9b7a041..f3bc01b 100644
> --- a/drivers/media/v4l2-core/videobuf2-dma-sg.c
> +++ b/drivers/media/v4l2-core/videobuf2-dma-sg.c
> @@ -170,6 +170,22 @@ static void vb2_dma_sg_put(void *buf_priv)
> }
> }
>
> +static void vb2_dma_sg_prepare(void *buf_priv)
> +{
> + struct vb2_dma_sg_buf *buf = buf_priv;
> + struct sg_table *sgt = &buf->sg_table;
> +
> + dma_map_sg(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
Shouldn't you use dma_sync_sg_for_device (and dma_sync_sg_for_cpu below)
instead ? Mapping/unmapping the buffer can be costly when an IOMMU is
involved.
> +}
> +
> +static void vb2_dma_sg_finish(void *buf_priv)
> +{
> + struct vb2_dma_sg_buf *buf = buf_priv;
> + struct sg_table *sgt = &buf->sg_table;
> +
> + dma_unmap_sg(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
> +}
> +
> static inline int vma_is_io(struct vm_area_struct *vma)
> {
> return !!(vma->vm_flags & (VM_IO | VM_PFNMAP));
> @@ -366,6 +382,8 @@ const struct vb2_mem_ops vb2_dma_sg_memops = {
> .put = vb2_dma_sg_put,
> .get_userptr = vb2_dma_sg_get_userptr,
> .put_userptr = vb2_dma_sg_put_userptr,
> + .prepare = vb2_dma_sg_prepare,
> + .finish = vb2_dma_sg_finish,
> .vaddr = vb2_dma_sg_vaddr,
> .mmap = vb2_dma_sg_mmap,
> .num_users = vb2_dma_sg_num_users,
--
Regards,
Laurent Pinchart
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