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| author | Hans Verkuil <hans.verkuil@cisco.com> | 2014-11-18 15:51:08 +0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@osg.samsung.com> | 2014-11-25 14:09:19 +0300 |
| commit | 251a79f8f5adfd816de4e052b5e3619a5a1d0910 (patch) | |
| tree | a0fbe2c43a495a274de4c083c42a7cc8dc99055b /drivers/media/v4l2-core/videobuf2-dma-contig.c | |
| parent | f5294f455afd30bdc90f31d6d0101bb773e9ddba (diff) | |
| download | linux-251a79f8f5adfd816de4e052b5e3619a5a1d0910.tar.xz | |
[media] vb2: use dma_map_sg_attrs to prevent unnecessary sync
By default dma_map_sg syncs the mapped buffer to the device. But
buf_prepare expects a buffer syncs for the cpu and the buffer
will be synced to the device in the prepare memop.
The reverse is true for dma_unmap_sg, buf_finish and the finish
memop.
To prevent unnecessary syncs we ask dma_(un)map_sg to skip the
sync.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Pawel Osciak <pawel@osciak.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Diffstat (limited to 'drivers/media/v4l2-core/videobuf2-dma-contig.c')
| -rw-r--r-- | drivers/media/v4l2-core/videobuf2-dma-contig.c | 24 |
1 files changed, 20 insertions, 4 deletions
diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c index 0bfc488c8812..b481d20c8372 100644 --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c @@ -511,7 +511,15 @@ static void vb2_dc_put_userptr(void *buf_priv) struct sg_table *sgt = buf->dma_sgt; if (sgt) { - dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir); + DEFINE_DMA_ATTRS(attrs); + + dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs); + /* + * No need to sync to CPU, it's already synced to the CPU + * since the finish() memop will have been called before this. + */ + dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, + buf->dma_dir, &attrs); if (!vma_is_io(buf->vma)) vb2_dc_sgt_foreach_page(sgt, vb2_dc_put_dirty_page); @@ -568,6 +576,9 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr, struct sg_table *sgt; unsigned long contig_size; unsigned long dma_align = dma_get_cache_alignment(); + DEFINE_DMA_ATTRS(attrs); + + dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs); /* Only cache aligned DMA transfers are reliable */ if (!IS_ALIGNED(vaddr | size, dma_align)) { @@ -654,8 +665,12 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr, kfree(pages); pages = NULL; - sgt->nents = dma_map_sg(buf->dev, sgt->sgl, sgt->orig_nents, - buf->dma_dir); + /* + * No need to sync to the device, this will happen later when the + * prepare() memop is called. + */ + sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, + buf->dma_dir, &attrs); if (sgt->nents <= 0) { pr_err("failed to map scatterlist\n"); ret = -EIO; @@ -677,7 +692,8 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr, return buf; fail_map_sg: - dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir); + dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, + buf->dma_dir, &attrs); fail_sgt_init: if (!vma_is_io(buf->vma)) |