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[media] v4l: vb2-dma-contig: add support for DMABUF exporting
This patch adds support for exporting a dma-contig buffer using DMABUF interface. Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Tested-by: Mauro Carvalho Chehab <mchehab@redhat.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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@ -36,6 +36,7 @@ struct vb2_dc_buf {
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/* MMAP related */
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struct vb2_vmarea_handler handler;
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atomic_t refcount;
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struct sg_table *sgt_base;
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/* USERPTR related */
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struct vm_area_struct *vma;
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@ -142,6 +143,10 @@ static void vb2_dc_put(void *buf_priv)
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if (!atomic_dec_and_test(&buf->refcount))
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return;
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if (buf->sgt_base) {
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sg_free_table(buf->sgt_base);
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kfree(buf->sgt_base);
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}
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dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr);
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kfree(buf);
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}
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@ -212,6 +217,200 @@ static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
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return 0;
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}
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/*********************************************/
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/* DMABUF ops for exporters */
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/*********************************************/
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struct vb2_dc_attachment {
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struct sg_table sgt;
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enum dma_data_direction dir;
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};
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static int vb2_dc_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev,
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struct dma_buf_attachment *dbuf_attach)
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{
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struct vb2_dc_attachment *attach;
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unsigned int i;
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struct scatterlist *rd, *wr;
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struct sg_table *sgt;
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struct vb2_dc_buf *buf = dbuf->priv;
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int ret;
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attach = kzalloc(sizeof(*attach), GFP_KERNEL);
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if (!attach)
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return -ENOMEM;
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sgt = &attach->sgt;
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/* Copy the buf->base_sgt scatter list to the attachment, as we can't
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* map the same scatter list to multiple attachments at the same time.
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*/
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ret = sg_alloc_table(sgt, buf->sgt_base->orig_nents, GFP_KERNEL);
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if (ret) {
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kfree(attach);
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return -ENOMEM;
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}
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rd = buf->sgt_base->sgl;
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wr = sgt->sgl;
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for (i = 0; i < sgt->orig_nents; ++i) {
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sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
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rd = sg_next(rd);
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wr = sg_next(wr);
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}
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attach->dir = DMA_NONE;
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dbuf_attach->priv = attach;
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return 0;
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}
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static void vb2_dc_dmabuf_ops_detach(struct dma_buf *dbuf,
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struct dma_buf_attachment *db_attach)
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{
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struct vb2_dc_attachment *attach = db_attach->priv;
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struct sg_table *sgt;
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if (!attach)
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return;
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sgt = &attach->sgt;
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/* release the scatterlist cache */
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if (attach->dir != DMA_NONE)
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dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
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attach->dir);
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sg_free_table(sgt);
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kfree(attach);
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db_attach->priv = NULL;
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}
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static struct sg_table *vb2_dc_dmabuf_ops_map(
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struct dma_buf_attachment *db_attach, enum dma_data_direction dir)
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{
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struct vb2_dc_attachment *attach = db_attach->priv;
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/* stealing dmabuf mutex to serialize map/unmap operations */
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struct mutex *lock = &db_attach->dmabuf->lock;
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struct sg_table *sgt;
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int ret;
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mutex_lock(lock);
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sgt = &attach->sgt;
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/* return previously mapped sg table */
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if (attach->dir == dir) {
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mutex_unlock(lock);
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return sgt;
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}
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/* release any previous cache */
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if (attach->dir != DMA_NONE) {
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dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
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attach->dir);
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attach->dir = DMA_NONE;
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}
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/* mapping to the client with new direction */
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ret = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, dir);
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if (ret <= 0) {
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pr_err("failed to map scatterlist\n");
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mutex_unlock(lock);
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return ERR_PTR(-EIO);
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}
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attach->dir = dir;
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mutex_unlock(lock);
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return sgt;
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}
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static void vb2_dc_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
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struct sg_table *sgt, enum dma_data_direction dir)
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{
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/* nothing to be done here */
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}
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static void vb2_dc_dmabuf_ops_release(struct dma_buf *dbuf)
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{
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/* drop reference obtained in vb2_dc_get_dmabuf */
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vb2_dc_put(dbuf->priv);
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}
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static void *vb2_dc_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum)
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{
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struct vb2_dc_buf *buf = dbuf->priv;
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return buf->vaddr + pgnum * PAGE_SIZE;
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}
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static void *vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf)
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{
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struct vb2_dc_buf *buf = dbuf->priv;
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return buf->vaddr;
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}
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static int vb2_dc_dmabuf_ops_mmap(struct dma_buf *dbuf,
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struct vm_area_struct *vma)
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{
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return vb2_dc_mmap(dbuf->priv, vma);
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}
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static struct dma_buf_ops vb2_dc_dmabuf_ops = {
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.attach = vb2_dc_dmabuf_ops_attach,
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.detach = vb2_dc_dmabuf_ops_detach,
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.map_dma_buf = vb2_dc_dmabuf_ops_map,
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.unmap_dma_buf = vb2_dc_dmabuf_ops_unmap,
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.kmap = vb2_dc_dmabuf_ops_kmap,
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.kmap_atomic = vb2_dc_dmabuf_ops_kmap,
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.vmap = vb2_dc_dmabuf_ops_vmap,
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.mmap = vb2_dc_dmabuf_ops_mmap,
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.release = vb2_dc_dmabuf_ops_release,
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};
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static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf)
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{
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int ret;
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struct sg_table *sgt;
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sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
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if (!sgt) {
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dev_err(buf->dev, "failed to alloc sg table\n");
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return NULL;
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}
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ret = dma_get_sgtable(buf->dev, sgt, buf->vaddr, buf->dma_addr,
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buf->size);
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if (ret < 0) {
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dev_err(buf->dev, "failed to get scatterlist from DMA API\n");
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kfree(sgt);
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return NULL;
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}
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return sgt;
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}
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static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv)
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{
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struct vb2_dc_buf *buf = buf_priv;
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struct dma_buf *dbuf;
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if (!buf->sgt_base)
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buf->sgt_base = vb2_dc_get_base_sgt(buf);
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if (WARN_ON(!buf->sgt_base))
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return NULL;
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dbuf = dma_buf_export(buf, &vb2_dc_dmabuf_ops, buf->size, 0);
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if (IS_ERR(dbuf))
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return NULL;
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/* dmabuf keeps reference to vb2 buffer */
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atomic_inc(&buf->refcount);
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return dbuf;
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}
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/*********************************************/
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/* callbacks for USERPTR buffers */
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/*********************************************/
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@ -519,6 +718,7 @@ static void *vb2_dc_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
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const struct vb2_mem_ops vb2_dma_contig_memops = {
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.alloc = vb2_dc_alloc,
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.put = vb2_dc_put,
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.get_dmabuf = vb2_dc_get_dmabuf,
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.cookie = vb2_dc_cookie,
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.vaddr = vb2_dc_vaddr,
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.mmap = vb2_dc_mmap,
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