[media] v4l: add buffer exporting via dmabuf

This patch adds extension to V4L2 api. A new ioctl VIDIOC_EXPBUF is added.  The
ioctl is used to export an mmap buffer as a DMABUF file descriptor.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Tested-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

3 files changed, 12 insertions, 0 deletions

diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
index cc5998b31463..7157af301b14 100644
--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -1018,6 +1018,7 @@ 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/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
index a2df842e5100..98dcad9c8a3b 100644
--- a/drivers/media/v4l2-core/v4l2-dev.c
+++ b/drivers/media/v4l2-core/v4l2-dev.c
@@ -571,6 +571,7 @@ 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_STREAMON, vidioc_streamon);
         SET_VALID_IOCTL(ops, VIDIOC_STREAMOFF, vidioc_streamoff);
diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 530a67e3fe0e..aa6e7c788db2 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -454,6 +454,15 @@ static void v4l_print_buffer(const void *arg, bool write_only)
                         tc->type, tc->flags, tc->frames, *(__u32 *)tc->userbits);
 }
 
+static void v4l_print_exportbuffer(const void *arg, bool write_only)
+{
+        const struct v4l2_exportbuffer *p = arg;
+
+        pr_cont("fd=%d, type=%s, index=%u, plane=%u, flags=0x%08x\n",
+                p->fd, prt_names(p->type, v4l2_type_names),
+                p->index, p->plane, p->flags);
+}
+
 static void v4l_print_create_buffers(const void *arg, bool write_only)
 {
         const struct v4l2_create_buffers *p = arg;
@@ -1961,6 +1970,7 @@ static struct v4l2_ioctl_info v4l2_ioctls[] = {
         IOCTL_INFO_STD(VIDIOC_S_FBUF, vidioc_s_fbuf, v4l_print_framebuffer, INFO_FL_PRIO),
         IOCTL_INFO_FNC(VIDIOC_OVERLAY, v4l_overlay, v4l_print_u32, INFO_FL_PRIO),
         IOCTL_INFO_FNC(VIDIOC_QBUF, v4l_qbuf, v4l_print_buffer, INFO_FL_QUEUE),
+        IOCTL_INFO_STD(VIDIOC_EXPBUF, vidioc_expbuf, v4l_print_exportbuffer, INFO_FL_QUEUE | INFO_FL_CLEAR(v4l2_exportbuffer, flags)),
         IOCTL_INFO_FNC(VIDIOC_DQBUF, v4l_dqbuf, v4l_print_buffer, INFO_FL_QUEUE),
         IOCTL_INFO_FNC(VIDIOC_STREAMON, v4l_streamon, v4l_print_buftype, INFO_FL_PRIO | INFO_FL_QUEUE),
         IOCTL_INFO_FNC(VIDIOC_STREAMOFF, v4l_streamoff, v4l_print_buftype, INFO_FL_PRIO | INFO_FL_QUEUE),