From 251a79f8f5adfd816de4e052b5e3619a5a1d0910 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Tue, 18 Nov 2014 09:51:08 -0300 Subject: [PATCH] [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 Acked-by: Pawel Osciak Signed-off-by: Mauro Carvalho Chehab --- drivers/media/v4l2-core/videobuf2-dma-contig.c | 24 +++++++++++++++---- drivers/media/v4l2-core/videobuf2-dma-sg.c | 33 +++++++++++++++++++++----- 2 files changed, 47 insertions(+), 10 deletions(-) diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c index 0bfc488..b481d20 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)) diff --git a/drivers/media/v4l2-core/videobuf2-dma-sg.c b/drivers/media/v4l2-core/videobuf2-dma-sg.c index 0566e94..b1838ab 100644 --- a/drivers/media/v4l2-core/videobuf2-dma-sg.c +++ b/drivers/media/v4l2-core/videobuf2-dma-sg.c @@ -107,6 +107,9 @@ static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size, struct sg_table *sgt; int ret; int num_pages; + DEFINE_DMA_ATTRS(attrs); + + dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs); if (WARN_ON(alloc_ctx == NULL)) return NULL; @@ -140,9 +143,13 @@ static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size, buf->dev = get_device(conf->dev); sgt = &buf->sg_table; - if (dma_map_sg(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir) == 0) + /* + * No need to sync to the device, this will happen later when the + * prepare() memop is called. + */ + if (dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->nents, + buf->dma_dir, &attrs) == 0) goto fail_map; - dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir); buf->handler.refcount = &buf->refcount; buf->handler.put = vb2_dma_sg_put; @@ -175,9 +182,13 @@ static void vb2_dma_sg_put(void *buf_priv) int i = buf->num_pages; if (atomic_dec_and_test(&buf->refcount)) { + DEFINE_DMA_ATTRS(attrs); + + dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs); dprintk(1, "%s: Freeing buffer of %d pages\n", __func__, buf->num_pages); - dma_unmap_sg(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir); + dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->nents, + buf->dma_dir, &attrs); if (buf->vaddr) vm_unmap_ram(buf->vaddr, buf->num_pages); sg_free_table(buf->dma_sgt); @@ -228,6 +239,9 @@ static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr, int num_pages_from_user; struct vm_area_struct *vma; struct sg_table *sgt; + DEFINE_DMA_ATTRS(attrs); + + dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs); buf = kzalloc(sizeof *buf, GFP_KERNEL); if (!buf) @@ -296,9 +310,13 @@ static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr, goto userptr_fail_alloc_table_from_pages; sgt = &buf->sg_table; - if (dma_map_sg(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir) == 0) + /* + * No need to sync to the device, this will happen later when the + * prepare() memop is called. + */ + if (dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->nents, + buf->dma_dir, &attrs) == 0) goto userptr_fail_map; - dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir); return buf; userptr_fail_map: @@ -327,10 +345,13 @@ static void vb2_dma_sg_put_userptr(void *buf_priv) struct vb2_dma_sg_buf *buf = buf_priv; struct sg_table *sgt = &buf->sg_table; int i = buf->num_pages; + DEFINE_DMA_ATTRS(attrs); + + dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs); dprintk(1, "%s: Releasing userspace buffer of %d pages\n", __func__, buf->num_pages); - dma_unmap_sg(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir); + dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir, &attrs); if (buf->vaddr) vm_unmap_ram(buf->vaddr, buf->num_pages); sg_free_table(buf->dma_sgt); -- 2.7.4