Hi Hans,
Thank you for the patch.
On Friday 12 September 2014 14:59:55 Hans Verkuil 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;
> 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 */
This isn't only about cache flushing. "DMABUF exporter will sync the memory
for us" would be more accurate. Same comment for vb2_dma_sg_finish.
> + 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");
> + 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 */
> + sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
> + if (IS_ERR_OR_NULL(sgt)) {
dma_buf_map_attachment() never returns NULL, you can use IS_ERR() and return
PTR_ERR(sgt).
> + pr_err("Error getting dmabuf scatterlist\n");
> + return -EINVAL;
> + }
> +
> + buf->dma_sgt = sgt;
> + return 0;
> +}
> +
> +static void vb2_dma_sg_unmap_dmabuf(void *mem_priv)
> +{
> + struct vb2_dma_sg_buf *buf = mem_priv;
> + struct sg_table *sgt = buf->dma_sgt;
> +
> + if (WARN_ON(!buf->db_attach)) {
> + pr_err("trying to unpin a not attached buffer\n");
> + return;
> + }
> +
> + if (WARN_ON(!sgt)) {
> + pr_err("dmabuf buffer is already unpinned\n");
> + return;
> + }
> +
> + dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
> +
> + buf->dma_sgt = NULL;
> +}
> +
> +static void vb2_dma_sg_detach_dmabuf(void *mem_priv)
> +{
> + struct vb2_dma_sg_buf *buf = mem_priv;
> +
> + /* if vb2 works correctly you should never detach mapped buffer */
> + if (WARN_ON(buf->dma_sgt))
> + vb2_dma_sg_unmap_dmabuf(buf);
> +
> + /* detach this attachment */
> + dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
> + kfree(buf);
> +}
> +
> +static void *vb2_dma_sg_attach_dmabuf(void *alloc_ctx, struct dma_buf
> *dbuf, + unsigned long size, int write)
> +{
> + struct vb2_dma_sg_conf *conf = alloc_ctx;
> + struct vb2_dma_sg_buf *buf;
> + struct dma_buf_attachment *dba;
> +
> + if (dbuf->size < size)
> + return ERR_PTR(-EFAULT);
> +
> + buf = kzalloc(sizeof(*buf), GFP_KERNEL);
> + if (!buf)
> + return ERR_PTR(-ENOMEM);
> +
> + buf->dev = conf->dev;
> + /* create attachment for the dmabuf with the user device */
> + dba = dma_buf_attach(dbuf, buf->dev);
> + if (IS_ERR(dba)) {
> + pr_err("failed to attach dmabuf\n");
> + kfree(buf);
> + return dba;
> + }
> +
> + buf->dma_dir = write ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
> + buf->size = size;
> + buf->db_attach = dba;
> +
> + return buf;
> +}
> +
> static void *vb2_dma_sg_cookie(void *buf_priv)
> {
> struct vb2_dma_sg_buf *buf = buf_priv;
>
> - return &buf->sg_table;
> + return buf->dma_sgt;
> }
>
> const struct vb2_mem_ops vb2_dma_sg_memops = {
> @@ -387,6 +494,10 @@ const struct vb2_mem_ops vb2_dma_sg_memops = {
> .vaddr = vb2_dma_sg_vaddr,
> .mmap = vb2_dma_sg_mmap,
> .num_users = vb2_dma_sg_num_users,
> + .map_dmabuf = vb2_dma_sg_map_dmabuf,
> + .unmap_dmabuf = vb2_dma_sg_unmap_dmabuf,
> + .attach_dmabuf = vb2_dma_sg_attach_dmabuf,
> + .detach_dmabuf = vb2_dma_sg_detach_dmabuf,
> .cookie = vb2_dma_sg_cookie,
> };
> EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);
--
Regards,
Laurent Pinchart
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