[media] v4l: vb2: add buffer exporting via dmabuf

This patch adds extension to videobuf2-core. It allow to export an mmap buffer as a DMABUF file descriptor. Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.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>

[media] v4l: vb2: add buffer exporting via dmabuf
This patch adds extension to videobuf2-core. It allow to export an mmap buffer as a DMABUF file descriptor. Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.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>
Tomasz Stanislawski · Mauro Carvalho Chehab
1 parent 19b6ef5164
Showing 4 changed files with 103 additions and 0 deletions Side-by-side Diff
drivers/media/v4l2-core/v4l2-mem2mem.c
drivers/media/v4l2-core/videobuf2-core.c
include/media/v4l2-mem2mem.h
include/media/videobuf2-core.h
@@ -369,6 +369,19 @@
 EXPORT_SYMBOL_GPL(v4l2_m2m_dqbuf);
  
 /**
+ * v4l2_m2m_expbuf() - export a source or destination buffer, depending on
+ * the type
+ */
+int v4l2_m2m_expbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
+		  struct v4l2_exportbuffer *eb)
+{
+	struct vb2_queue *vq;
+
+	vq = v4l2_m2m_get_vq(m2m_ctx, eb->type);
+	return vb2_expbuf(vq, eb);
+}
+EXPORT_SYMBOL_GPL(v4l2_m2m_expbuf);
+/**
  * v4l2_m2m_streamon() - turn on streaming for a video queue
  */
 int v4l2_m2m_streamon(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
@@ -1751,6 +1751,79 @@
 }
  
 /**
+ * vb2_expbuf() - Export a buffer as a file descriptor
+ * @q:		videobuf2 queue
+ * @eb:		export buffer structure passed from userspace to vidioc_expbuf
+ *		handler in driver
+ *
+ * The return values from this function are intended to be directly returned
+ * from vidioc_expbuf handler in driver.
+ */
+int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb)
+{
+	struct vb2_buffer *vb = NULL;
+	struct vb2_plane *vb_plane;
+	int ret;
+	struct dma_buf *dbuf;
+
+	if (q->memory != V4L2_MEMORY_MMAP) {
+		dprintk(1, "Queue is not currently set up for mmap\n");
+		return -EINVAL;
+	}
+
+	if (!q->mem_ops->get_dmabuf) {
+		dprintk(1, "Queue does not support DMA buffer exporting\n");
+		return -EINVAL;
+	}
+
+	if (eb->flags & ~O_CLOEXEC) {
+		dprintk(1, "Queue does support only O_CLOEXEC flag\n");
+		return -EINVAL;
+	}
+
+	if (eb->type != q->type) {
+		dprintk(1, "qbuf: invalid buffer type\n");
+		return -EINVAL;
+	}
+
+	if (eb->index >= q->num_buffers) {
+		dprintk(1, "buffer index out of range\n");
+		return -EINVAL;
+	}
+
+	vb = q->bufs[eb->index];
+
+	if (eb->plane >= vb->num_planes) {
+		dprintk(1, "buffer plane out of range\n");
+		return -EINVAL;
+	}
+
+	vb_plane = &vb->planes[eb->plane];
+
+	dbuf = call_memop(q, get_dmabuf, vb_plane->mem_priv);
+	if (IS_ERR_OR_NULL(dbuf)) {
+		dprintk(1, "Failed to export buffer %d, plane %d\n",
+			eb->index, eb->plane);
+		return -EINVAL;
+	}
+
+	ret = dma_buf_fd(dbuf, eb->flags);
+	if (ret < 0) {
+		dprintk(3, "buffer %d, plane %d failed to export (%d)\n",
+			eb->index, eb->plane, ret);
+		dma_buf_put(dbuf);
+		return ret;
+	}
+
+	dprintk(3, "buffer %d, plane %d exported as %d descriptor\n",
+		eb->index, eb->plane, ret);
+	eb->fd = ret;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(vb2_expbuf);
+
+/**
  * vb2_mmap() - map video buffers into application address space
  * @q:		videobuf2 queue
  * @vma:	vma passed to the mmap file operation handler in the driver
@@ -2455,6 +2528,16 @@
 	return vb2_streamoff(vdev->queue, i);
 }
 EXPORT_SYMBOL_GPL(vb2_ioctl_streamoff);
+
+int vb2_ioctl_expbuf(struct file *file, void *priv, struct v4l2_exportbuffer *p)
+{
+	struct video_device *vdev = video_devdata(file);
+
+	if (vb2_queue_is_busy(vdev, file))
+		return -EBUSY;
+	return vb2_expbuf(vdev->queue, p);
+}
+EXPORT_SYMBOL_GPL(vb2_ioctl_expbuf);
  
 /* v4l2_file_operations helpers */
  
@@ -111,6 +111,9 @@
 int v4l2_m2m_dqbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 		   struct v4l2_buffer *buf);
  
+int v4l2_m2m_expbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
+		   struct v4l2_exportbuffer *eb);
+
 int v4l2_m2m_streamon(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 		      enum v4l2_buf_type type);
 int v4l2_m2m_streamoff(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
@@ -81,6 +81,7 @@
 struct vb2_mem_ops {
 	void		*(*alloc)(void *alloc_ctx, unsigned long size);
 	void		(*put)(void *buf_priv);
+	struct dma_buf *(*get_dmabuf)(void *buf_priv);
  
 	void		*(*get_userptr)(void *alloc_ctx, unsigned long vaddr,
 					unsigned long size, int write);
@@ -363,6 +364,7 @@
 void vb2_queue_release(struct vb2_queue *q);
  
 int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b);
+int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb);
 int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking);
  
 int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type);
@@ -472,6 +474,8 @@
 int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p);
 int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i);
 int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i);
+int vb2_ioctl_expbuf(struct file *file, void *priv,
+	struct v4l2_exportbuffer *p);
  
 /* struct v4l2_file_operations helpers */
...	...	@@ -369,6 +369,19 @@
369	369	EXPORT_SYMBOL_GPL(v4l2_m2m_dqbuf);
370	370
371	371	/**
	372	+ * v4l2_m2m_expbuf() - export a source or destination buffer, depending on
	373	+ * the type
	374	+ */
	375	+int v4l2_m2m_expbuf(struct file file, struct v4l2_m2m_ctx m2m_ctx,
	376	+ struct v4l2_exportbuffer *eb)
	377	+{
	378	+ struct vb2_queue *vq;
	379	+
	380	+ vq = v4l2_m2m_get_vq(m2m_ctx, eb->type);
	381	+ return vb2_expbuf(vq, eb);
	382	+}
	383	+EXPORT_SYMBOL_GPL(v4l2_m2m_expbuf);
	384	+/**
372	385	* v4l2_m2m_streamon() - turn on streaming for a video queue
373	386	*/
374	387	int v4l2_m2m_streamon(struct file file, struct v4l2_m2m_ctx m2m_ctx,
...	...	@@ -1751,6 +1751,79 @@
1751	1751	}
1752	1752
1753	1753	/**
	1754	+ * vb2_expbuf() - Export a buffer as a file descriptor
	1755	+ * @q: videobuf2 queue
	1756	+ * @eb: export buffer structure passed from userspace to vidioc_expbuf
	1757	+ * handler in driver
	1758	+ *
	1759	+ * The return values from this function are intended to be directly returned
	1760	+ * from vidioc_expbuf handler in driver.
	1761	+ */
	1762	+int vb2_expbuf(struct vb2_queue q, struct v4l2_exportbuffer eb)
	1763	+{
	1764	+ struct vb2_buffer *vb = NULL;
	1765	+ struct vb2_plane *vb_plane;
	1766	+ int ret;
	1767	+ struct dma_buf *dbuf;
	1768	+
	1769	+ if (q->memory != V4L2_MEMORY_MMAP) {
	1770	+ dprintk(1, "Queue is not currently set up for mmap\n");
	1771	+ return -EINVAL;
	1772	+ }
	1773	+
	1774	+ if (!q->mem_ops->get_dmabuf) {
	1775	+ dprintk(1, "Queue does not support DMA buffer exporting\n");
	1776	+ return -EINVAL;
	1777	+ }
	1778	+
	1779	+ if (eb->flags & ~O_CLOEXEC) {
	1780	+ dprintk(1, "Queue does support only O_CLOEXEC flag\n");
	1781	+ return -EINVAL;
	1782	+ }
	1783	+
	1784	+ if (eb->type != q->type) {
	1785	+ dprintk(1, "qbuf: invalid buffer type\n");
	1786	+ return -EINVAL;
	1787	+ }
	1788	+
	1789	+ if (eb->index >= q->num_buffers) {
	1790	+ dprintk(1, "buffer index out of range\n");
	1791	+ return -EINVAL;
	1792	+ }
	1793	+
	1794	+ vb = q->bufs[eb->index];
	1795	+
	1796	+ if (eb->plane >= vb->num_planes) {
	1797	+ dprintk(1, "buffer plane out of range\n");
	1798	+ return -EINVAL;
	1799	+ }
	1800	+
	1801	+ vb_plane = &vb->planes[eb->plane];
	1802	+
	1803	+ dbuf = call_memop(q, get_dmabuf, vb_plane->mem_priv);
	1804	+ if (IS_ERR_OR_NULL(dbuf)) {
	1805	+ dprintk(1, "Failed to export buffer %d, plane %d\n",
	1806	+ eb->index, eb->plane);
	1807	+ return -EINVAL;
	1808	+ }
	1809	+
	1810	+ ret = dma_buf_fd(dbuf, eb->flags);
	1811	+ if (ret < 0) {
	1812	+ dprintk(3, "buffer %d, plane %d failed to export (%d)\n",
	1813	+ eb->index, eb->plane, ret);
	1814	+ dma_buf_put(dbuf);
	1815	+ return ret;
	1816	+ }
	1817	+
	1818	+ dprintk(3, "buffer %d, plane %d exported as %d descriptor\n",
	1819	+ eb->index, eb->plane, ret);
	1820	+ eb->fd = ret;
	1821	+
	1822	+ return 0;
	1823	+}
	1824	+EXPORT_SYMBOL_GPL(vb2_expbuf);
	1825	+
	1826	+/**
1754	1827	* vb2_mmap() - map video buffers into application address space
1755	1828	* @q: videobuf2 queue
1756	1829	* @vma: vma passed to the mmap file operation handler in the driver
...	...	@@ -2455,6 +2528,16 @@
2455	2528	return vb2_streamoff(vdev->queue, i);
2456	2529	}
2457	2530	EXPORT_SYMBOL_GPL(vb2_ioctl_streamoff);
	2531	+
	2532	+int vb2_ioctl_expbuf(struct file file, void priv, struct v4l2_exportbuffer *p)
	2533	+{
	2534	+ struct video_device *vdev = video_devdata(file);
	2535	+
	2536	+ if (vb2_queue_is_busy(vdev, file))
	2537	+ return -EBUSY;
	2538	+ return vb2_expbuf(vdev->queue, p);
	2539	+}
	2540	+EXPORT_SYMBOL_GPL(vb2_ioctl_expbuf);
2458	2541
2459	2542	/* v4l2_file_operations helpers */
2460	2543
...	...	@@ -111,6 +111,9 @@
111	111	int v4l2_m2m_dqbuf(struct file file, struct v4l2_m2m_ctx m2m_ctx,
112	112	struct v4l2_buffer *buf);
113	113
	114	+int v4l2_m2m_expbuf(struct file file, struct v4l2_m2m_ctx m2m_ctx,
	115	+ struct v4l2_exportbuffer *eb);
	116	+
114	117	int v4l2_m2m_streamon(struct file file, struct v4l2_m2m_ctx m2m_ctx,
115	118	enum v4l2_buf_type type);
116	119	int v4l2_m2m_streamoff(struct file file, struct v4l2_m2m_ctx m2m_ctx,
...	...	@@ -81,6 +81,7 @@
81	81	struct vb2_mem_ops {
82	82	void (alloc)(void *alloc_ctx, unsigned long size);
83	83	void (put)(void buf_priv);
	84	+ struct dma_buf (get_dmabuf)(void *buf_priv);
84	85
85	86	void (get_userptr)(void *alloc_ctx, unsigned long vaddr,
86	87	unsigned long size, int write);
...	...	@@ -363,6 +364,7 @@
363	364	void vb2_queue_release(struct vb2_queue *q);
364	365
365	366	int vb2_qbuf(struct vb2_queue q, struct v4l2_buffer b);
	367	+int vb2_expbuf(struct vb2_queue q, struct v4l2_exportbuffer eb);
366	368	int vb2_dqbuf(struct vb2_queue q, struct v4l2_buffer b, bool nonblocking);
367	369
368	370	int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type);
...	...	@@ -472,6 +474,8 @@
472	474	int vb2_ioctl_dqbuf(struct file file, void priv, struct v4l2_buffer *p);
473	475	int vb2_ioctl_streamon(struct file file, void priv, enum v4l2_buf_type i);
474	476	int vb2_ioctl_streamoff(struct file file, void priv, enum v4l2_buf_type i);
	477	+int vb2_ioctl_expbuf(struct file file, void priv,
	478	+ struct v4l2_exportbuffer *p);
475	479
476	480	/* struct v4l2_file_operations helpers */
477	481