[media] vb2-dma-sg: add support for dmabuf exports (041c7b6a) · Commits · e / devices / android_kernel_xiaomi_nabu

drivers/media/v4l2-core/videobuf2-dma-sg.c

+170 −0

Original line number	Original line	Diff line number	Diff line
	@@ -407,6 +407,175 @@ static int vb2_dma_sg_mmap(void buf_priv, struct vm_area_struct vma)
	return 0;		return 0;
	}		}

			/*********************************************/
			/* DMABUF ops for exporters */
			/*********************************************/

			struct vb2_dma_sg_attachment {
			struct sg_table sgt;
			enum dma_data_direction dma_dir;
			};

			static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf dbuf, struct device dev,
			struct dma_buf_attachment *dbuf_attach)
			{
			struct vb2_dma_sg_attachment *attach;
			unsigned int i;
			struct scatterlist rd, wr;
			struct sg_table *sgt;
			struct vb2_dma_sg_buf *buf = dbuf->priv;
			int ret;

			attach = kzalloc(sizeof(*attach), GFP_KERNEL);
			if (!attach)
			return -ENOMEM;

			sgt = &attach->sgt;
			/* Copy the buf->base_sgt scatter list to the attachment, as we can't
			* map the same scatter list to multiple attachments at the same time.
			*/
			ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL);
			if (ret) {
			kfree(attach);
			return -ENOMEM;
			}

			rd = buf->dma_sgt->sgl;
			wr = sgt->sgl;
			for (i = 0; i < sgt->orig_nents; ++i) {
			sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
			rd = sg_next(rd);
			wr = sg_next(wr);
			}

			attach->dma_dir = DMA_NONE;
			dbuf_attach->priv = attach;

			return 0;
			}

			static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf,
			struct dma_buf_attachment *db_attach)
			{
			struct vb2_dma_sg_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_dma_sg_dmabuf_ops_map(
			struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
			{
			struct vb2_dma_sg_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_dma_sg_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_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf)
			{
			/* drop reference obtained in vb2_dma_sg_get_dmabuf */
			vb2_dma_sg_put(dbuf->priv);
			}

			static void vb2_dma_sg_dmabuf_ops_kmap(struct dma_buf dbuf, unsigned long pgnum)
			{
			struct vb2_dma_sg_buf *buf = dbuf->priv;

			return buf->vaddr ? buf->vaddr + pgnum * PAGE_SIZE : NULL;
			}

			static void vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf dbuf)
			{
			struct vb2_dma_sg_buf *buf = dbuf->priv;

			return vb2_dma_sg_vaddr(buf);
			}

			static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf,
			struct vm_area_struct *vma)
			{
			return vb2_dma_sg_mmap(dbuf->priv, vma);
			}

			static struct dma_buf_ops vb2_dma_sg_dmabuf_ops = {
			.attach = vb2_dma_sg_dmabuf_ops_attach,
			.detach = vb2_dma_sg_dmabuf_ops_detach,
			.map_dma_buf = vb2_dma_sg_dmabuf_ops_map,
			.unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap,
			.kmap = vb2_dma_sg_dmabuf_ops_kmap,
			.kmap_atomic = vb2_dma_sg_dmabuf_ops_kmap,
			.vmap = vb2_dma_sg_dmabuf_ops_vmap,
			.mmap = vb2_dma_sg_dmabuf_ops_mmap,
			.release = vb2_dma_sg_dmabuf_ops_release,
			};

			static struct dma_buf vb2_dma_sg_get_dmabuf(void buf_priv, unsigned long flags)
			{
			struct vb2_dma_sg_buf *buf = buf_priv;
			struct dma_buf *dbuf;

			if (WARN_ON(!buf->dma_sgt))
			return NULL;

			dbuf = dma_buf_export(buf, &vb2_dma_sg_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 */		/* callbacks for DMABUF buffers */
	/*********************************************/		/*********************************************/
	@@ -523,6 +692,7 @@ const struct vb2_mem_ops vb2_dma_sg_memops = {
	.vaddr = vb2_dma_sg_vaddr,		.vaddr = vb2_dma_sg_vaddr,
	.mmap = vb2_dma_sg_mmap,		.mmap = vb2_dma_sg_mmap,
	.num_users = vb2_dma_sg_num_users,		.num_users = vb2_dma_sg_num_users,
			.get_dmabuf = vb2_dma_sg_get_dmabuf,
	.map_dmabuf = vb2_dma_sg_map_dmabuf,		.map_dmabuf = vb2_dma_sg_map_dmabuf,
	.unmap_dmabuf = vb2_dma_sg_unmap_dmabuf,		.unmap_dmabuf = vb2_dma_sg_unmap_dmabuf,
	.attach_dmabuf = vb2_dma_sg_attach_dmabuf,		.attach_dmabuf = vb2_dma_sg_attach_dmabuf,