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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
@@ -924,11 +924,12 @@ 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
@@ -1050,6 +1051,8 @@ 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 */
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