On Tue, Mar 13, 2012 at 11:17:02AM +0100, Tomasz Stanislawski wrote:
This patch adds extension to V4L2 api. It allow to export a mmap buffer as file descriptor. New ioctl VIDIOC_EXPBUF is added. It takes a buffer offset used by mmap and return a file descriptor on success.
Signed-off-by: Tomasz Stanislawski t.stanislaws@samsung.com Signed-off-by: Kyungmin Park kyungmin.park@samsung.com
Just a quick comment: You need to add a flags parameter to at least support O_CLOSEXEC semantics on the returned fd. Otherwise library writes will plainly hate you and demand a new version with this support added. -Daniel
drivers/media/video/v4l2-compat-ioctl32.c | 1 + drivers/media/video/v4l2-ioctl.c | 11 +++++++++++ include/linux/videodev2.h | 20 ++++++++++++++++++++ include/media/v4l2-ioctl.h | 2 ++ 4 files changed, 34 insertions(+), 0 deletions(-)
diff --git a/drivers/media/video/v4l2-compat-ioctl32.c b/drivers/media/video/v4l2-compat-ioctl32.c index e6f67aa..fd157cb 100644 --- a/drivers/media/video/v4l2-compat-ioctl32.c +++ b/drivers/media/video/v4l2-compat-ioctl32.c @@ -954,6 +954,7 @@ long v4l2_compat_ioctl32(struct file *file, unsigned int cmd, unsigned long arg) case VIDIOC_S_FBUF32: case VIDIOC_OVERLAY32: case VIDIOC_QBUF32:
- case VIDIOC_EXPBUF: case VIDIOC_DQBUF32: case VIDIOC_STREAMON32: case VIDIOC_STREAMOFF32:
diff --git a/drivers/media/video/v4l2-ioctl.c b/drivers/media/video/v4l2-ioctl.c index 74cab51..a125016 100644 --- a/drivers/media/video/v4l2-ioctl.c +++ b/drivers/media/video/v4l2-ioctl.c @@ -207,6 +207,7 @@ static const char *v4l2_ioctls[] = { [_IOC_NR(VIDIOC_S_FBUF)] = "VIDIOC_S_FBUF", [_IOC_NR(VIDIOC_OVERLAY)] = "VIDIOC_OVERLAY", [_IOC_NR(VIDIOC_QBUF)] = "VIDIOC_QBUF",
- [_IOC_NR(VIDIOC_EXPBUF)] = "VIDIOC_EXPBUF", [_IOC_NR(VIDIOC_DQBUF)] = "VIDIOC_DQBUF", [_IOC_NR(VIDIOC_STREAMON)] = "VIDIOC_STREAMON", [_IOC_NR(VIDIOC_STREAMOFF)] = "VIDIOC_STREAMOFF",
@@ -938,6 +939,16 @@ static long __video_do_ioctl(struct file *file, dbgbuf(cmd, vfd, p); break; }
- case VIDIOC_EXPBUF:
- {
struct v4l2_exportbuffer *p = arg;if (!ops->vidioc_expbuf)break;ret = ops->vidioc_expbuf(file, fh, p);break;- } case VIDIOC_DQBUF: { struct v4l2_buffer *p = arg;
diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h index bb6844e..e71c787 100644 --- a/include/linux/videodev2.h +++ b/include/linux/videodev2.h @@ -680,6 +680,25 @@ struct v4l2_buffer { #define V4L2_BUF_FLAG_NO_CACHE_INVALIDATE 0x0800 #define V4L2_BUF_FLAG_NO_CACHE_CLEAN 0x1000 +/**
- struct v4l2_exportbuffer - export of video buffer as DMABUF file descriptor
- @fd: file descriptor associated with DMABUF (set by driver)
- @mem_offset: for non-multiplanar buffers with memory == V4L2_MEMORY_MMAP;
offset from the start of the device memory for this plane,
(or a "cookie" that should be passed to mmap() as offset)
- Contains data used for exporting a video buffer as DMABUF file
- descriptor. Uses the same 'cookie' as mmap() syscall. All reserved fields
- must be set to zero.
- */
+struct v4l2_exportbuffer {
- __u32 fd;
- __u32 reserved0;
- __u32 mem_offset;
- __u32 reserved[13];
+};
/*
- O V E R L A Y P R E V I E W
*/ @@ -2303,6 +2322,7 @@ struct v4l2_create_buffers { #define VIDIOC_S_FBUF _IOW('V', 11, struct v4l2_framebuffer) #define VIDIOC_OVERLAY _IOW('V', 14, int) #define VIDIOC_QBUF _IOWR('V', 15, struct v4l2_buffer) +#define VIDIOC_EXPBUF _IOWR('V', 16, struct v4l2_exportbuffer) #define VIDIOC_DQBUF _IOWR('V', 17, struct v4l2_buffer) #define VIDIOC_STREAMON _IOW('V', 18, int) #define VIDIOC_STREAMOFF _IOW('V', 19, int) diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h index 4df031a..d8716c6f 100644 --- a/include/media/v4l2-ioctl.h +++ b/include/media/v4l2-ioctl.h @@ -120,6 +120,8 @@ struct v4l2_ioctl_ops { int (*vidioc_reqbufs) (struct file *file, void *fh, struct v4l2_requestbuffers *b); int (*vidioc_querybuf)(struct file *file, void *fh, struct v4l2_buffer *b); int (*vidioc_qbuf) (struct file *file, void *fh, struct v4l2_buffer *b);
- int (*vidioc_expbuf) (struct file *file, void *fh,
struct v4l2_exportbuffer *e);int (*vidioc_create_bufs)(struct file *file, void *fh, struct v4l2_create_buffers *b); -- 1.7.5.4