[openwrt/openwrt.git] / target / linux / bcm27xx / patches-5.4 / 950-0494-media-vb2-add-V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF.patch

From dfcdc4ed9a514cd5d77dd18c6527f257f8aaf378 Mon Sep 17 00:00:00 2001
From: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Date: Fri, 11 Oct 2019 06:32:40 -0300
Subject: [PATCH] media: vb2: add V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF

This patch adds support for the V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF
flag.

It also adds a new V4L2_BUF_CAP_SUPPORTS_M2M_HOLD_CAPTURE_BUF
capability.

Drivers should set vb2_queue->subsystem_flags to
VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF to indicate support
for this flag.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
---
 Documentation/media/uapi/v4l/buffer.rst         | 13 +++++++++++++
 Documentation/media/uapi/v4l/vidioc-reqbufs.rst |  6 ++++++
 drivers/media/common/videobuf2/videobuf2-v4l2.c | 12 ++++++++++--
 include/media/videobuf2-core.h                  |  3 +++
 include/media/videobuf2-v4l2.h                  |  5 +++++
 include/uapi/linux/videodev2.h                  | 13 ++++++++-----
 6 files changed, 45 insertions(+), 7 deletions(-)

--- a/Documentation/media/uapi/v4l/buffer.rst
+++ b/Documentation/media/uapi/v4l/buffer.rst
@@ -607,6 +607,19 @@ Buffer Flags
        applications shall use this flag for output buffers if the data in
        this buffer has not been created by the CPU but by some
        DMA-capable unit, in which case caches have not been used.
+    * .. _`V4L2-BUF-FLAG-M2M-HOLD-CAPTURE-BUF`:
+
+      - ``V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF``
+      - 0x00000200
+      - Only valid if ``V4L2_BUF_CAP_SUPPORTS_M2M_HOLD_CAPTURE_BUF`` is
+       set. It is typically used with stateless decoders where multiple
+       output buffers each decode to a slice of the decoded frame.
+       Applications can set this flag when queueing the output buffer
+       to prevent the driver from dequeueing the capture buffer after
+       the output buffer has been decoded (i.e. the capture buffer is
+       'held'). If the timestamp of this output buffer differs from that
+       of the previous output buffer, then that indicates the start of a
+       new frame and the previously held capture buffer is dequeued.
     * .. _`V4L2-BUF-FLAG-LAST`:
 
       - ``V4L2_BUF_FLAG_LAST``
--- a/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
+++ b/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
@@ -125,6 +125,7 @@ aborting or finishing any DMA in progres
 .. _V4L2-BUF-CAP-SUPPORTS-DMABUF:
 .. _V4L2-BUF-CAP-SUPPORTS-REQUESTS:
 .. _V4L2-BUF-CAP-SUPPORTS-ORPHANED-BUFS:
+.. _V4L2-BUF-CAP-SUPPORTS-M2M-HOLD-CAPTURE-BUF:
 
 .. cssclass:: longtable
 
@@ -150,6 +151,11 @@ aborting or finishing any DMA in progres
       - The kernel allows calling :ref:`VIDIOC_REQBUFS` while buffers are still
         mapped or exported via DMABUF. These orphaned buffers will be freed
         when they are unmapped or when the exported DMABUF fds are closed.
+    * - ``V4L2_BUF_CAP_SUPPORTS_M2M_HOLD_CAPTURE_BUF``
+      - 0x00000020
+      - Only valid for stateless decoders. If set, then userspace can set the
+        ``V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF`` flag to hold off on returning the
+       capture buffer until the OUTPUT timestamp changes.
 
 Return Value
 ============
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
@@ -49,8 +49,11 @@ module_param(debug, int, 0644);
                                 V4L2_BUF_FLAG_REQUEST_FD | \
                                 V4L2_BUF_FLAG_TIMESTAMP_MASK)
 /* Output buffer flags that should be passed on to the driver */
-#define V4L2_BUFFER_OUT_FLAGS  (V4L2_BUF_FLAG_PFRAME | V4L2_BUF_FLAG_BFRAME | \
-                                V4L2_BUF_FLAG_KEYFRAME | V4L2_BUF_FLAG_TIMECODE)
+#define V4L2_BUFFER_OUT_FLAGS  (V4L2_BUF_FLAG_PFRAME | \
+                                V4L2_BUF_FLAG_BFRAME | \
+                                V4L2_BUF_FLAG_KEYFRAME | \
+                                V4L2_BUF_FLAG_TIMECODE | \
+                                V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF)
 
 /*
  * __verify_planes_array() - verify that the planes array passed in struct
@@ -194,6 +197,7 @@ static int vb2_fill_vb2_v4l2_buffer(stru
        }
        vbuf->sequence = 0;
        vbuf->request_fd = -1;
+       vbuf->is_held = false;
 
        if (V4L2_TYPE_IS_MULTIPLANAR(b->type)) {
                switch (b->memory) {
@@ -321,6 +325,8 @@ static int vb2_fill_vb2_v4l2_buffer(stru
                 */
                vbuf->flags &= ~V4L2_BUF_FLAG_TIMECODE;
                vbuf->field = b->field;
+               if (!(q->subsystem_flags & VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF))
+                       vbuf->flags &= ~V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF;
        } else {
                /* Zero any output buffer flags as this is a capture buffer */
                vbuf->flags &= ~V4L2_BUFFER_OUT_FLAGS;
@@ -654,6 +660,8 @@ static void fill_buf_caps(struct vb2_que
                *caps |= V4L2_BUF_CAP_SUPPORTS_USERPTR;
        if (q->io_modes & VB2_DMABUF)
                *caps |= V4L2_BUF_CAP_SUPPORTS_DMABUF;
+       if (q->subsystem_flags & VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF)
+               *caps |= V4L2_BUF_CAP_SUPPORTS_M2M_HOLD_CAPTURE_BUF;
 #ifdef CONFIG_MEDIA_CONTROLLER_REQUEST_API
        if (q->supports_requests)
                *caps |= V4L2_BUF_CAP_SUPPORTS_REQUESTS;
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -505,6 +505,8 @@ struct vb2_buf_ops {
  * @buf_ops:   callbacks to deliver buffer information.
  *             between user-space and kernel-space.
  * @drv_priv:  driver private data.
+ * @subsystem_flags: Flags specific to the subsystem (V4L2/DVB/etc.). Not used
+ *             by the vb2 core.
  * @buf_struct_size: size of the driver-specific buffer structure;
  *             "0" indicates the driver doesn't want to use a custom buffer
  *             structure type. for example, ``sizeof(struct vb2_v4l2_buffer)``
@@ -571,6 +573,7 @@ struct vb2_queue {
        const struct vb2_buf_ops        *buf_ops;
 
        void                            *drv_priv;
+       u32                             subsystem_flags;
        unsigned int                    buf_struct_size;
        u32                             timestamp_flags;
        gfp_t                           gfp_flags;
--- a/include/media/videobuf2-v4l2.h
+++ b/include/media/videobuf2-v4l2.h
@@ -33,6 +33,7 @@
  * @timecode:  frame timecode.
  * @sequence:  sequence count of this frame.
  * @request_fd:        the request_fd associated with this buffer
+ * @is_held:   if true, then this capture buffer was held
  * @planes:    plane information (userptr/fd, length, bytesused, data_offset).
  *
  * Should contain enough information to be able to cover all the fields
@@ -46,9 +47,13 @@ struct vb2_v4l2_buffer {
        struct v4l2_timecode    timecode;
        __u32                   sequence;
        __s32                   request_fd;
+       bool                    is_held;
        struct vb2_plane        planes[VB2_MAX_PLANES];
 };
 
+/* VB2 V4L2 flags as set in vb2_queue.subsystem_flags */
+#define VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF (1 << 0)
+
 /*
  * to_vb2_v4l2_buffer() - cast struct vb2_buffer * to struct vb2_v4l2_buffer *
  */
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -925,11 +925,12 @@ struct v4l2_requestbuffers {
 };
 
 /* capabilities for struct v4l2_requestbuffers and v4l2_create_buffers */
-#define V4L2_BUF_CAP_SUPPORTS_MMAP     (1 << 0)
-#define V4L2_BUF_CAP_SUPPORTS_USERPTR  (1 << 1)
-#define V4L2_BUF_CAP_SUPPORTS_DMABUF   (1 << 2)
-#define V4L2_BUF_CAP_SUPPORTS_REQUESTS (1 << 3)
-#define V4L2_BUF_CAP_SUPPORTS_ORPHANED_BUFS (1 << 4)
+#define V4L2_BUF_CAP_SUPPORTS_MMAP                     (1 << 0)
+#define V4L2_BUF_CAP_SUPPORTS_USERPTR                  (1 << 1)
+#define V4L2_BUF_CAP_SUPPORTS_DMABUF                   (1 << 2)
+#define V4L2_BUF_CAP_SUPPORTS_REQUESTS                 (1 << 3)
+#define V4L2_BUF_CAP_SUPPORTS_ORPHANED_BUFS            (1 << 4)
+#define V4L2_BUF_CAP_SUPPORTS_M2M_HOLD_CAPTURE_BUF     (1 << 5)
 
 /**
  * struct v4l2_plane - plane info for multi-planar buffers
@@ -1051,6 +1052,8 @@ static inline __u64 v4l2_timeval_to_ns(c
 #define V4L2_BUF_FLAG_IN_REQUEST               0x00000080
 /* timecode field is valid */
 #define V4L2_BUF_FLAG_TIMECODE                 0x00000100
+/* Don't return the capture buffer until OUTPUT timestamp changes */
+#define V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF     0x00000200
 /* Buffer is prepared for queuing */
 #define V4L2_BUF_FLAG_PREPARED                 0x00000400
 /* Cache handling flags */