Re: [Linaro-mm-sig] [PATCHv8 19/26] v4l: vb2: add buffer exporting via dmabuf

On Tue August 14 2012 17:34:49 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 Acked-by: Laurent Pinchart laurent.pinchart@ideasonboard.com

---

drivers/media/video/videobuf2-core.c | 67 ++++++++++++++++++++++++++++++++++ include/media/videobuf2-core.h | 2 + 2 files changed, 69 insertions(+)

diff --git a/drivers/media/video/videobuf2-core.c b/drivers/media/video/videobuf2-core.c index aed21e4..61354ec 100644 --- a/drivers/media/video/videobuf2-core.c +++ b/drivers/media/video/videobuf2-core.c @@ -1743,6 +1743,73 @@ static int __find_plane_by_offset(struct vb2_queue *q, unsigned long off, } /**

• • 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;
• 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;
  

• }
• if (eb->flags & ~O_CLOEXEC) {

• dprintk(1, "Queue does support only O_CLOEXEC flag\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, eb->flags);
• if (ret < 0) {

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

• 	buffer, plane, ret);
  

• dma_buf_put(dbuf);
  

• 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_mmap() - map video buffers into application address space
• @q: videobuf2 queue
• @vma: vma passed to the mmap file operation handler in the driver

diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h index c306fec..b034424 100644 --- a/include/media/videobuf2-core.h +++ b/include/media/videobuf2-core.h @@ -81,6 +81,7 @@ struct vb2_fileio_data; 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 @@ 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);

Please add a vb2_ioctl_expbuf helper function as well!

Regards,

Hans