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>

Adds DMABUF memory type to v4l framework. Also adds the related file
descriptor in v4l2_plane and v4l2_buffer.
   [original work in the PoC for buffer sharing]

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Sumit Semwal <sumit.semwal@ti.com>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.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>

Judging from what drivers do and from my experience temeperframe
fraction is set in seconds - look e.g. here
    static int bttv_g_parm(struct file *file, void *f,
                                    struct v4l2_streamparm *parm)
    {
            struct bttv_fh *fh = f;
            struct bttv *btv = fh->btv;
            v4l2_video_std_frame_period(bttv_tvnorms[btv->tvnorm].v4l2_id,
                                        &parm->parm.capture.timeperframe);
    ...
    void v4l2_video_std_frame_period(int id, struct v4l2_fract *frameperiod)
    {
            if (id & V4L2_STD_525_60) {
                    frameperiod->numerator = 1001;
                    frameperiod->denominator = 30000;
            } else {
                    frameperiod->numerator = 1;
                    frameperiod->denominator = 25;
            }
and also v4l2-ctl in userspace decodes this as seconds:
    if (doioctl(fd, VIDIOC_G_PARM, &parm, "VIDIOC_G_PARM") == 0) {
            const struct v4l2_fract &tf = parm.parm.capture.timeperframe;
            ...
            printf("\tFrames per second: %.3f (%d/%d)\n",
                            (1.0 * tf.denominator) / tf.numerator,
                            tf.denominator, tf.numerator);
The typo was there from day 1 - added in 2002 in e028b61b ([PATCH]
add v4l2 api)(*)
(*) found in history tree
    git://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git

Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>