On Tue, Nov 18, 2014 at 9:51 PM, Hans Verkuil <hverkuil@xxxxxxxxx> wrote:
> From: Hans Verkuil <hansverk@xxxxxxxxx>
>
> Add support for DMABUF exporting to the vb2-vmalloc implementation.
>
> All memory models now have support for both importing and exporting of DMABUFs.
>
> Signed-off-by: Hans Verkuil <hansverk@xxxxxxxxx>
Acked-by: Pawel Osciak <pawel@xxxxxxxxxx>
> ---
> drivers/media/v4l2-core/videobuf2-vmalloc.c | 171 ++++++++++++++++++++++++++++
> 1 file changed, 171 insertions(+)
>
> diff --git a/drivers/media/v4l2-core/videobuf2-vmalloc.c b/drivers/media/v4l2-core/videobuf2-vmalloc.c
> index bba2460..3966b12 100644
> --- a/drivers/media/v4l2-core/videobuf2-vmalloc.c
> +++ b/drivers/media/v4l2-core/videobuf2-vmalloc.c
> @@ -213,6 +213,176 @@ static int vb2_vmalloc_mmap(void *buf_priv, struct vm_area_struct *vma)
> }
>
> /*********************************************/
> +/* DMABUF ops for exporters */
> +/*********************************************/
> +
> +struct vb2_vmalloc_attachment {
> + struct sg_table sgt;
> + enum dma_data_direction dma_dir;
> +};
> +
> +static int vb2_vmalloc_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev,
> + struct dma_buf_attachment *dbuf_attach)
> +{
> + struct vb2_vmalloc_attachment *attach;
> + struct vb2_vmalloc_buf *buf = dbuf->priv;
> + int num_pages = PAGE_ALIGN(buf->size) / PAGE_SIZE;
> + struct sg_table *sgt;
> + struct scatterlist *sg;
> + void *vaddr = buf->vaddr;
> + int ret;
> + int i;
> +
> + attach = kzalloc(sizeof(*attach), GFP_KERNEL);
> + if (!attach)
> + return -ENOMEM;
> +
> + sgt = &attach->sgt;
> + ret = sg_alloc_table(sgt, num_pages, GFP_KERNEL);
> + if (ret) {
> + kfree(attach);
> + return ret;
> + }
> + for_each_sg(sgt->sgl, sg, sgt->nents, i) {
> + struct page *page = vmalloc_to_page(vaddr);
> +
> + if (!page) {
> + sg_free_table(sgt);
> + kfree(attach);
> + return -ENOMEM;
> + }
> + sg_set_page(sg, page, PAGE_SIZE, 0);
> + vaddr += PAGE_SIZE;
> + }
> +
> + attach->dma_dir = DMA_NONE;
> + dbuf_attach->priv = attach;
> + return 0;
> +}
> +
> +static void vb2_vmalloc_dmabuf_ops_detach(struct dma_buf *dbuf,
> + struct dma_buf_attachment *db_attach)
> +{
> + struct vb2_vmalloc_attachment *attach = db_attach->priv;
> + struct sg_table *sgt;
> +
> + if (!attach)
> + return;
> +
> + sgt = &attach->sgt;
> +
> + /* release the scatterlist cache */
> + if (attach->dma_dir != DMA_NONE)
> + dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
> + attach->dma_dir);
> + sg_free_table(sgt);
> + kfree(attach);
> + db_attach->priv = NULL;
> +}
> +
> +static struct sg_table *vb2_vmalloc_dmabuf_ops_map(
> + struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
> +{
> + struct vb2_vmalloc_attachment *attach = db_attach->priv;
> + /* stealing dmabuf mutex to serialize map/unmap operations */
> + struct mutex *lock = &db_attach->dmabuf->lock;
> + struct sg_table *sgt;
> + int ret;
> +
> + mutex_lock(lock);
> +
> + sgt = &attach->sgt;
> + /* return previously mapped sg table */
> + if (attach->dma_dir == dma_dir) {
> + mutex_unlock(lock);
> + return sgt;
> + }
> +
> + /* release any previous cache */
> + if (attach->dma_dir != DMA_NONE) {
> + dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
> + attach->dma_dir);
> + attach->dma_dir = DMA_NONE;
> + }
> +
> + /* mapping to the client with new direction */
> + ret = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, dma_dir);
> + if (ret <= 0) {
> + pr_err("failed to map scatterlist\n");
> + mutex_unlock(lock);
> + return ERR_PTR(-EIO);
> + }
> +
> + attach->dma_dir = dma_dir;
> +
> + mutex_unlock(lock);
> +
> + return sgt;
> +}
> +
> +static void vb2_vmalloc_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
> + struct sg_table *sgt, enum dma_data_direction dma_dir)
> +{
> + /* nothing to be done here */
> +}
> +
> +static void vb2_vmalloc_dmabuf_ops_release(struct dma_buf *dbuf)
> +{
> + /* drop reference obtained in vb2_vmalloc_get_dmabuf */
> + vb2_vmalloc_put(dbuf->priv);
> +}
> +
> +static void *vb2_vmalloc_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum)
> +{
> + struct vb2_vmalloc_buf *buf = dbuf->priv;
> +
> + return buf->vaddr + pgnum * PAGE_SIZE;
> +}
> +
> +static void *vb2_vmalloc_dmabuf_ops_vmap(struct dma_buf *dbuf)
> +{
> + struct vb2_vmalloc_buf *buf = dbuf->priv;
> +
> + return buf->vaddr;
> +}
> +
> +static int vb2_vmalloc_dmabuf_ops_mmap(struct dma_buf *dbuf,
> + struct vm_area_struct *vma)
> +{
> + return vb2_vmalloc_mmap(dbuf->priv, vma);
> +}
> +
> +static struct dma_buf_ops vb2_vmalloc_dmabuf_ops = {
> + .attach = vb2_vmalloc_dmabuf_ops_attach,
> + .detach = vb2_vmalloc_dmabuf_ops_detach,
> + .map_dma_buf = vb2_vmalloc_dmabuf_ops_map,
> + .unmap_dma_buf = vb2_vmalloc_dmabuf_ops_unmap,
> + .kmap = vb2_vmalloc_dmabuf_ops_kmap,
> + .kmap_atomic = vb2_vmalloc_dmabuf_ops_kmap,
> + .vmap = vb2_vmalloc_dmabuf_ops_vmap,
> + .mmap = vb2_vmalloc_dmabuf_ops_mmap,
> + .release = vb2_vmalloc_dmabuf_ops_release,
> +};
> +
> +static struct dma_buf *vb2_vmalloc_get_dmabuf(void *buf_priv, unsigned long flags)
> +{
> + struct vb2_vmalloc_buf *buf = buf_priv;
> + struct dma_buf *dbuf;
> +
> + if (WARN_ON(!buf->vaddr))
> + return NULL;
> +
> + dbuf = dma_buf_export(buf, &vb2_vmalloc_dmabuf_ops, buf->size, flags, NULL);
> + if (IS_ERR(dbuf))
> + return NULL;
> +
> + /* dmabuf keeps reference to vb2 buffer */
> + atomic_inc(&buf->refcount);
> +
> + return dbuf;
> +}
> +
> +/*********************************************/
> /* callbacks for DMABUF buffers */
> /*********************************************/
>
> @@ -268,6 +438,7 @@ const struct vb2_mem_ops vb2_vmalloc_memops = {
> .put = vb2_vmalloc_put,
> .get_userptr = vb2_vmalloc_get_userptr,
> .put_userptr = vb2_vmalloc_put_userptr,
> + .get_dmabuf = vb2_vmalloc_get_dmabuf,
> .map_dmabuf = vb2_vmalloc_map_dmabuf,
> .unmap_dmabuf = vb2_vmalloc_unmap_dmabuf,
> .attach_dmabuf = vb2_vmalloc_attach_dmabuf,
> --
> 2.1.1
>
--
Best regards,
Pawel Osciak
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