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.stanisl...@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.p...@samsung.com>
---
 drivers/media/video/v4l2-compat-ioctl32.c |    1 +
 drivers/media/video/v4l2-dev.c            |    1 +
 drivers/media/video/v4l2-ioctl.c          |    6 ++++++
 include/linux/videodev2.h                 |   26 ++++++++++++++++++++++++++
 include/media/v4l2-ioctl.h                |    2 ++
 5 files changed, 36 insertions(+)

diff --git a/drivers/media/video/v4l2-compat-ioctl32.c 
b/drivers/media/video/v4l2-compat-ioctl32.c
index 5327ad3..45159d9 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-dev.c b/drivers/media/video/v4l2-dev.c
index 5ccbd46..6bf6307 100644
--- a/drivers/media/video/v4l2-dev.c
+++ b/drivers/media/video/v4l2-dev.c
@@ -597,6 +597,7 @@ static void determine_valid_ioctls(struct video_device 
*vdev)
        SET_VALID_IOCTL(ops, VIDIOC_REQBUFS, vidioc_reqbufs);
        SET_VALID_IOCTL(ops, VIDIOC_QUERYBUF, vidioc_querybuf);
        SET_VALID_IOCTL(ops, VIDIOC_QBUF, vidioc_qbuf);
+       SET_VALID_IOCTL(ops, VIDIOC_EXPBUF, vidioc_expbuf);
        SET_VALID_IOCTL(ops, VIDIOC_DQBUF, vidioc_dqbuf);
        SET_VALID_IOCTL(ops, VIDIOC_OVERLAY, vidioc_overlay);
        SET_VALID_IOCTL(ops, VIDIOC_G_FBUF, vidioc_g_fbuf);
diff --git a/drivers/media/video/v4l2-ioctl.c b/drivers/media/video/v4l2-ioctl.c
index 31fc2ad..a73b14e 100644
--- a/drivers/media/video/v4l2-ioctl.c
+++ b/drivers/media/video/v4l2-ioctl.c
@@ -212,6 +212,7 @@ static struct v4l2_ioctl_info v4l2_ioctls[] = {
        IOCTL_INFO(VIDIOC_S_FBUF, INFO_FL_PRIO),
        IOCTL_INFO(VIDIOC_OVERLAY, INFO_FL_PRIO),
        IOCTL_INFO(VIDIOC_QBUF, 0),
+       IOCTL_INFO(VIDIOC_EXPBUF, 0),
        IOCTL_INFO(VIDIOC_DQBUF, 0),
        IOCTL_INFO(VIDIOC_STREAMON, INFO_FL_PRIO),
        IOCTL_INFO(VIDIOC_STREAMOFF, INFO_FL_PRIO),
@@ -957,6 +958,11 @@ static long __video_do_ioctl(struct file *file,
                        dbgbuf(cmd, vfd, p);
                break;
        }
+       case VIDIOC_EXPBUF:
+       {
+               ret = ops->vidioc_expbuf(file, fh, arg);
+               break;
+       }
        case VIDIOC_DQBUF:
        {
                struct v4l2_buffer *p = arg;
diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
index 51b20f4..e8893a5 100644
--- a/include/linux/videodev2.h
+++ b/include/linux/videodev2.h
@@ -684,6 +684,31 @@ 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];
+};
+
 /*
  *     O V E R L A Y   P R E V I E W
  */
@@ -2553,6 +2578,7 @@ 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 d8b76f7..ccd1faa 100644
--- a/include/media/v4l2-ioctl.h
+++ b/include/media/v4l2-ioctl.h
@@ -119,6 +119,8 @@ 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_dqbuf)   (struct file *file, void *fh, struct v4l2_buffer 
*b);
 
        int (*vidioc_create_bufs)(struct file *file, void *fh, struct 
v4l2_create_buffers *b);
-- 
1.7.9.5

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