Hi Tomasz,
Thanks for the patch.
On Tuesday 14 August 2012 17:34:48 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@xxxxxxxxxxx>
> Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
> ---
> drivers/media/video/v4l2-compat-ioctl32.c | 1 +
> drivers/media/video/v4l2-dev.c | 1 +
> drivers/media/video/v4l2-ioctl.c | 15 +++++++++++++++
> include/linux/videodev2.h | 26 ++++++++++++++++++++++++++
> include/media/v4l2-ioctl.h | 2 ++
> 5 files changed, 45 insertions(+)
[snip]
> b/include/linux/videodev2.h index 7f918dc..b5d058b 100644
> --- a/include/linux/videodev2.h
> +++ b/include/linux/videodev2.h
> @@ -688,6 +688,31 @@ 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: buffer memory offset as returned by VIDIOC_QUERYBUF in
> struct
> + * v4l2_buffer::m.offset (for single-plane formats) or
> + * v4l2_plane::m.offset (for multi-planar formats)
> + * @flags: flags for newly created file, currently only O_CLOEXEC is
> + * supported, refer to manual of open syscall for more details
> + *
> + * Contains data used for exporting a video buffer as DMABUF file
> descriptor.
> + * The buffer is identified by a 'cookie' returned by VIDIOC_QUERYBUF
> + * (identical to the cookie used to mmap() the buffer to userspace). All
> + * reserved fields must be set to zero. The field reserved0 is expected to
> + * become a structure 'type' allowing an alternative layout of the
> structure
> + * content. Therefore this field should not be used for any other
> extensions.
> + */
> +struct v4l2_exportbuffer {
> + __u32 fd;
> + __u32 reserved0;
> + __u32 mem_offset;
> + __u32 flags;
> + __u32 reserved[12];
> +};
As Hans recently pointed out, this could be layed out as
struct v4l2_exportbuffer {
__u32 fd;
__u32 memory;
union {
__u32 mem_offset;
unsigned long userptr;
} m;
__u32 flags;
__u32 reserved[12];
};
32-bit compatibility code would need to be added.
--
Regards,
Laurent Pinchart
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