Hi Hans,
Thank you for the patch.
On Fri, Nov 7, 2014 at 5:50 PM, Hans Verkuil <hverkuil@xxxxxxxxx> wrote:
> From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
>
> Add support for dmabuf to vb2-dma-sg.
importing dmabuf into videobuf2-dma-sg.
>
> Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> ---
> drivers/media/v4l2-core/videobuf2-dma-sg.c | 126 +++++++++++++++++++++++++++--
> 1 file changed, 119 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/videobuf2-dma-sg.c b/drivers/media/v4l2-core/videobuf2-dma-sg.c
> index 7375923..2795c27 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;
Perhaps it would be useful to add a comment when this points to
sg_table and when not...
> size_t size;
> unsigned int num_pages;
> atomic_t refcount;
> struct vb2_vmarea_handler handler;
> struct vm_area_struct *vma;
> +
> + /* DMABUF related */
I'd remove this comment.
> + struct dma_buf_attachment *db_attach;
> };
>
> static void vb2_dma_sg_put(void *buf_priv);
> @@ -114,6 +118,7 @@ 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);
> @@ -124,7 +129,7 @@ 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_KERNEL);
> if (ret)
> goto fail_table_alloc;
> @@ -173,7 +178,7 @@ static void vb2_dma_sg_put(void *buf_priv)
> dma_unmap_sg(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
> 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);
> @@ -185,7 +190,11 @@ 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;
> + struct sg_table *sgt = buf->dma_sgt;
> +
> + /* DMABUF exporter will flush the cache for us */
> + if (buf->db_attach)
> + return;
>
> dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
> }
> @@ -193,7 +202,11 @@ static void 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_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
> }
> @@ -222,6 +235,7 @@ 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;
> @@ -274,7 +288,7 @@ 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;
>
> @@ -319,7 +333,7 @@ static void vb2_dma_sg_put_userptr(void *buf_priv)
> dma_unmap_sg(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
> 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]);
> @@ -392,11 +406,105 @@ 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)) {
Hm, this was changed to IS_ERR() in dma-contig quite a long time ago
(see http://git.linuxtv.org/cgit.cgi/media_tree.git/commit/drivers/media/v4l2-core/videobuf2-dma-contig.c?id=fee0c54e28f6ca187add93dfca226a8093cfa931).
Are you basing this on an old version of dma-contig?
> + pr_err("Error getting dmabuf scatterlist\n");
> + return -EINVAL;
> + }
> +
> + buf->dma_sgt = sgt;
In another patch also upstream in contig
(http://git.linuxtv.org/cgit.cgi/media_tree.git/commit/drivers/media/v4l2-core/videobuf2-dma-contig.c?id=6bbd4fec0cd93823fe651fa3907bee2bc6c814f6),
we have
buf->vaddr = NULL;
> +
> + 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 */
I'd remove this comment, it's not that correct either.
> + 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 = {
> @@ -409,6 +517,10 @@ 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);
> --
> 2.1.1
>
--
Best regards,
Pawel Osciak
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