Hi Hans,
Thank you for the patch.
On Mon, Sep 8, 2014 at 10:14 PM, Hans Verkuil <hverkuil@xxxxxxxxx> wrote:
> From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
>
> Add support for dmabuf to vb2-dma-sg.
>
> Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> ---
> drivers/media/v4l2-core/videobuf2-dma-sg.c | 125 +++++++++++++++++++++++++++--
> 1 file changed, 118 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/videobuf2-dma-sg.c b/drivers/media/v4l2-core/videobuf2-dma-sg.c
> index abd5252..6d922c0 100644
> --- a/drivers/media/v4l2-core/videobuf2-dma-sg.c
> +++ b/drivers/media/v4l2-core/videobuf2-dma-sg.c
> @@ -42,11 +42,15 @@ struct vb2_dma_sg_buf {
> int offset;
> enum dma_data_direction dma_dir;
> struct sg_table sg_table;
> + struct sg_table *dma_sgt;
I think we should document and/or have a bit better naming here. Maybe
sgt_in_use?
> size_t size;
> unsigned int num_pages;
> atomic_t refcount;
> struct vb2_vmarea_handler handler;
> struct vm_area_struct *vma;
> +
> + /* DMABUF related */
> + struct dma_buf_attachment *db_attach;
> };
>
> static void vb2_dma_sg_put(void *buf_priv);
> @@ -113,6 +117,7 @@ static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size, int write,
> /* size is already page aligned */
> buf->num_pages = size >> PAGE_SHIFT;
> buf->dma_dir = write ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
> + buf->dma_sgt = &buf->sg_table;
>
> buf->pages = kzalloc(buf->num_pages * sizeof(struct page *),
> GFP_KERNEL);
> @@ -123,7 +128,7 @@ static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size, int write,
> if (ret)
> goto fail_pages_alloc;
>
> - ret = sg_alloc_table_from_pages(&buf->sg_table, buf->pages,
> + ret = sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
> buf->num_pages, 0, size, gfp_flags);
> if (ret)
> goto fail_table_alloc;
> @@ -161,7 +166,7 @@ static void vb2_dma_sg_put(void *buf_priv)
> buf->num_pages);
> if (buf->vaddr)
> vm_unmap_ram(buf->vaddr, buf->num_pages);
> - sg_free_table(&buf->sg_table);
> + sg_free_table(buf->dma_sgt);
> while (--i >= 0)
> __free_page(buf->pages[i]);
> kfree(buf->pages);
> @@ -173,7 +178,11 @@ static void vb2_dma_sg_put(void *buf_priv)
> static int vb2_dma_sg_prepare(void *buf_priv)
> {
> struct vb2_dma_sg_buf *buf = buf_priv;
> - struct sg_table *sgt = &buf->sg_table;
> + struct sg_table *sgt = buf->dma_sgt;
> +
> + /* DMABUF exporter will flush the cache for us */
> + if (buf->db_attach)
> + return 0;
>
> return dma_map_sg(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir) ? 0 : -EIO;
> }
> @@ -181,7 +190,11 @@ static int vb2_dma_sg_prepare(void *buf_priv)
> static void vb2_dma_sg_finish(void *buf_priv)
> {
> struct vb2_dma_sg_buf *buf = buf_priv;
> - struct sg_table *sgt = &buf->sg_table;
> + struct sg_table *sgt = buf->dma_sgt;
> +
> + /* DMABUF exporter will flush the cache for us */
> + if (buf->db_attach)
> + return;
>
> dma_unmap_sg(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
> }
> @@ -209,6 +222,7 @@ static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr,
> buf->offset = vaddr & ~PAGE_MASK;
> buf->size = size;
> buf->dma_dir = write ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
> + buf->dma_sgt = &buf->sg_table;
>
> first = (vaddr & PAGE_MASK) >> PAGE_SHIFT;
> last = ((vaddr + size - 1) & PAGE_MASK) >> PAGE_SHIFT;
> @@ -261,7 +275,7 @@ static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr,
> if (num_pages_from_user != buf->num_pages)
> goto userptr_fail_get_user_pages;
>
> - if (sg_alloc_table_from_pages(&buf->sg_table, buf->pages,
> + if (sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
> buf->num_pages, buf->offset, size, 0))
> goto userptr_fail_alloc_table_from_pages;
>
> @@ -297,7 +311,7 @@ static void vb2_dma_sg_put_userptr(void *buf_priv)
> __func__, buf->num_pages);
> if (buf->vaddr)
> vm_unmap_ram(buf->vaddr, buf->num_pages);
> - sg_free_table(&buf->sg_table);
> + sg_free_table(buf->dma_sgt);
> while (--i >= 0) {
> if (buf->write)
> set_page_dirty_lock(buf->pages[i]);
> @@ -370,11 +384,104 @@ static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma)
> return 0;
> }
>
> +/*********************************************/
> +/* callbacks for DMABUF buffers */
> +/*********************************************/
> +
> +static int vb2_dma_sg_map_dmabuf(void *mem_priv)
> +{
> + struct vb2_dma_sg_buf *buf = mem_priv;
> + struct sg_table *sgt;
> +
> + if (WARN_ON(!buf->db_attach)) {
> + pr_err("trying to pin a non attached buffer\n");
s/a non attached/an unattached/
In general, it would perhaps be nice to clean up/pretty up messages in
this file while we have the chance please...
> + return -EINVAL;
> + }
> +
> + if (WARN_ON(buf->dma_sgt)) {
> + pr_err("dmabuf buffer is already pinned\n");
> + return 0;
> + }
> +
> + /* get the associated scatterlist for this buffer */
This comment doesn't really add value, and there is a few like this around.
I know they are copied from dma-contig, but I think we should remove them.
Others include "detach", "create attachment", etc.
--
Best regards,
Pawel Osciak
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