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 | 66 ++++++++++++++++++++++++++++++++++ include/media/videobuf2-core.h | 2 + 2 files changed, 68 insertions(+), 0 deletions(-)
diff --git a/drivers/media/video/videobuf2-core.c b/drivers/media/video/videobuf2-core.c index b37feea..ff902aa 100644 --- a/drivers/media/video/videobuf2-core.c +++ b/drivers/media/video/videobuf2-core.c @@ -1710,6 +1710,72 @@ 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 + * @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; + } + + if (eb->flags & ~O_CLOEXEC) { + dprintk(1, "Queue supports 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); + 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 244165a..3bd4225 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); @@ -354,6 +355,7 @@ 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);