Re: [Linaro-mm-sig] [RFCv2 PATCH 5/9] v4l: vb2: add buffer exporting via dmabuf

Hi Tomasz,

Thanks for the patch.

On Tuesday 13 March 2012 11:17:03 Tomasz Stanislawski wrote:

This patch adds extension to videobuf2-core. It allow to export a mmap buffer as a file descriptor.

Signed-off-by: Tomasz Stanislawski t.stanislaws@samsung.com Signed-off-by: Kyungmin Park kyungmin.park@samsung.com

---

drivers/media/video/videobuf2-core.c | 64 ++++++++++++++++++++++++++++++++++ include/media/videobuf2-core.h | 2 + 2 files changed, 66 insertions(+), 0 deletions(-)

diff --git a/drivers/media/video/videobuf2-core.c b/drivers/media/video/videobuf2-core.c index e7df560..41c4bf8 100644 --- a/drivers/media/video/videobuf2-core.c +++ b/drivers/media/video/videobuf2-core.c @@ -1553,6 +1553,70 @@ int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking) } EXPORT_SYMBOL_GPL(vb2_dqbuf);

+static int __find_plane_by_offset(struct vb2_queue *q, unsigned long off,

• 	unsigned int *_buffer, unsigned int *_plane);
  

Could you please move __find_plane_by_offset() up or move vb2_expbuf() down to avoid the forward declaration ? The later might make more sense, you could declare vb2_expbuf() right after vb2_mmap() (here and in videobuf2-core.h), both functions perform similar tasks.

+/**

• • vb2_expbuf() - Export a buffer as a file descriptor
• • @q: videobuf2 queue
• • @b: 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;
• unsigned int buffer, 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;
  

• }
• /*

• * Find the plane corresponding to the offset passed by userspace.
  

• */
  

• ret = __find_plane_by_offset(q, eb->mem_offset, &buffer, &plane);
• if (ret) {

• dprintk(1, "invalid offset %u\n", eb->mem_offset);
  

• return ret;
  

• }
• vb = q->bufs[buffer];
• vb_plane = &vb->planes[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",
  

• 	buffer, plane);
  

• return -EINVAL;
  

• }
• ret = dma_buf_fd(dbuf);
• if (ret < 0) {

• dprintk(3, "buffer %d, plane %d failed to export (%d)\n",
  

• 	buffer, plane, ret);
  

• return ret;
  

• }
• dprintk(3, "buffer %d, plane %d exported as %d descriptor\n",

• buffer, plane, ret);
  

• eb->fd = ret;
• return 0;

+} +EXPORT_SYMBOL_GPL(vb2_expbuf);

/**

• __vb2_queue_cancel() - cancel and stop (pause) streaming

diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h index 412c6a4..548252b 100644 --- a/include/media/videobuf2-core.h +++ b/include/media/videobuf2-core.h @@ -79,6 +79,7 @@ struct vb2_mem_ops { void (*prepare)(void *buf_priv); void (*finish)(void *buf_priv); 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);

@@ -348,6 +349,7 @@ int vb2_queue_init(struct vb2_queue *q); 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);