[media] v4l: Add DMABUF as a memory type

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>

3 files changed, 26 insertions, 0 deletions

diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
index 83ffb6436baf..cc5998b31463 100644
--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -297,6 +297,7 @@ struct v4l2_plane32 {
         union {
                 __u32           mem_offset;
                 compat_long_t   userptr;
+                __s32           fd;
         } m;
         __u32                   data_offset;
         __u32                   reserved[11];
@@ -318,6 +319,7 @@ struct v4l2_buffer32 {
                 __u32           offset;
                 compat_long_t   userptr;
                 compat_caddr_t  planes;
+                __s32           fd;
         } m;
         __u32                   length;
         __u32                   reserved2;
@@ -341,6 +343,9 @@ static int get_v4l2_plane32(struct v4l2_plane *up, struct v4l2_plane32 *up32,
                 up_pln = compat_ptr(p);
                 if (put_user((unsigned long)up_pln, &up->m.userptr))
                         return -EFAULT;
+        } else if (memory == V4L2_MEMORY_DMABUF) {
+                if (copy_in_user(&up->m.fd, &up32->m.fd, sizeof(int)))
+                        return -EFAULT;
         } else {
                 if (copy_in_user(&up->m.mem_offset, &up32->m.mem_offset,
                                         sizeof(__u32)))
@@ -364,6 +369,11 @@ static int put_v4l2_plane32(struct v4l2_plane *up, struct v4l2_plane32 *up32,
                 if (copy_in_user(&up32->m.mem_offset, &up->m.mem_offset,
                                         sizeof(__u32)))
                         return -EFAULT;
+        /* For DMABUF, driver might've set up the fd, so copy it back. */
+        if (memory == V4L2_MEMORY_DMABUF)
+                if (copy_in_user(&up32->m.fd, &up->m.fd,
+                                        sizeof(int)))
+                        return -EFAULT;
 
         return 0;
 }
@@ -446,6 +456,10 @@ static int get_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
                         if (get_user(kp->m.offset, &up->m.offset))
                                 return -EFAULT;
                         break;
+                case V4L2_MEMORY_DMABUF:
+                        if (get_user(kp->m.fd, &up->m.fd))
+                                return -EFAULT;
+                        break;
                 }
         }
 
@@ -510,6 +524,10 @@ static int put_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
                         if (put_user(kp->m.offset, &up->m.offset))
                                 return -EFAULT;
                         break;
+                case V4L2_MEMORY_DMABUF:
+                        if (put_user(kp->m.fd, &up->m.fd))
+                                return -EFAULT;
+                        break;
                 }
         }
 
diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 8f388ff31ebb..530a67e3fe0e 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -155,6 +155,7 @@ static const char *v4l2_memory_names[] = {
         [V4L2_MEMORY_MMAP]    = "mmap",
         [V4L2_MEMORY_USERPTR] = "userptr",
         [V4L2_MEMORY_OVERLAY] = "overlay",
+        [V4L2_MEMORY_DMABUF] = "dmabuf",
 };
 
 #define prt_names(a, arr) (((unsigned)(a)) < ARRAY_SIZE(arr) ? arr[a] : "unknown")
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 2fff7ff3e05b..91ac83b21c20 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -186,6 +186,7 @@ enum v4l2_memory {
         V4L2_MEMORY_MMAP             = 1,
         V4L2_MEMORY_USERPTR          = 2,
         V4L2_MEMORY_OVERLAY          = 3,
+        V4L2_MEMORY_DMABUF           = 4,
 };
 
 /* see also http://vektor.theorem.ca/graphics/ycbcr/ */
@@ -602,6 +603,8 @@ struct v4l2_requestbuffers {
  *                      should be passed to mmap() called on the video node)
  * @userptr:            when memory is V4L2_MEMORY_USERPTR, a userspace pointer
  *                      pointing to this plane
+ * @fd:                 when memory is V4L2_MEMORY_DMABUF, a userspace file
+ *                      descriptor associated with this plane
  * @data_offset:        offset in the plane to the start of data; usually 0,
  *                      unless there is a header in front of the data
  *
@@ -616,6 +619,7 @@ struct v4l2_plane {
         union {
                 __u32           mem_offset;
                 unsigned long   userptr;
+                __s32           fd;
         } m;
         __u32                   data_offset;
         __u32                   reserved[11];
@@ -640,6 +644,8 @@ struct v4l2_plane {
  *              (or a "cookie" that should be passed to mmap() as offset)
  * @userptr:    for non-multiplanar buffers with memory == V4L2_MEMORY_USERPTR;
  *              a userspace pointer pointing to this buffer
+ * @fd:         for non-multiplanar buffers with memory == V4L2_MEMORY_DMABUF;
+ *              a userspace file descriptor associated with this buffer
  * @planes:     for multiplanar buffers; userspace pointer to the array of plane
  *              info structs for this buffer
  * @length:     size in bytes of the buffer (NOT its payload) for single-plane
@@ -666,6 +672,7 @@ struct v4l2_buffer {
                 __u32           offset;
                 unsigned long   userptr;
                 struct v4l2_plane *planes;
+                __s32           fd;
         } m;
         __u32                   length;
         __u32                   reserved2;