blob: 02e2342df24f3ef2829727340d3c5d9c606acbb8 [file] [log] [blame]
* videobuf2-core.h - Video Buffer 2 Core Framework
* Copyright (C) 2010 Samsung Electronics
* Author: Pawel Osciak <>
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation.
#include <linux/mm_types.h>
#include <linux/mutex.h>
#include <linux/poll.h>
#include <linux/dma-buf.h>
#define VB2_MAX_FRAME (32)
#define VB2_MAX_PLANES (8)
enum vb2_memory {
struct vb2_alloc_ctx;
struct vb2_fileio_data;
struct vb2_threadio_data;
* struct vb2_mem_ops - memory handling/memory allocator operations
* @alloc: allocate video memory and, optionally, allocator private data,
* return NULL on failure or a pointer to allocator private,
* per-buffer data on success; the returned private structure
* will then be passed as buf_priv argument to other ops in this
* structure. Additional gfp_flags to use when allocating the
* are also passed to this operation. These flags are from the
* gfp_flags field of vb2_queue.
* @put: inform the allocator that the buffer will no longer be used;
* usually will result in the allocator freeing the buffer (if
* no other users of this buffer are present); the buf_priv
* argument is the allocator private per-buffer structure
* previously returned from the alloc callback.
* @get_dmabuf: acquire userspace memory for a hardware operation; used for
* DMABUF memory types.
* @get_userptr: acquire userspace memory for a hardware operation; used for
* USERPTR memory types; vaddr is the address passed to the
* videobuf layer when queuing a video buffer of USERPTR type;
* should return an allocator private per-buffer structure
* associated with the buffer on success, NULL on failure;
* the returned private structure will then be passed as buf_priv
* argument to other ops in this structure.
* @put_userptr: inform the allocator that a USERPTR buffer will no longer
* be used.
* @attach_dmabuf: attach a shared struct dma_buf for a hardware operation;
* used for DMABUF memory types; alloc_ctx is the alloc context
* dbuf is the shared dma_buf; returns NULL on failure;
* allocator private per-buffer structure on success;
* this needs to be used for further accesses to the buffer.
* @detach_dmabuf: inform the exporter of the buffer that the current DMABUF
* buffer is no longer used; the buf_priv argument is the
* allocator private per-buffer structure previously returned
* from the attach_dmabuf callback.
* @map_dmabuf: request for access to the dmabuf from allocator; the allocator
* of dmabuf is informed that this driver is going to use the
* dmabuf.
* @unmap_dmabuf: releases access control to the dmabuf - allocator is notified
* that this driver is done using the dmabuf for now.
* @prepare: called every time the buffer is passed from userspace to the
* driver, useful for cache synchronisation, optional.
* @finish: called every time the buffer is passed back from the driver
* to the userspace, also optional.
* @vaddr: return a kernel virtual address to a given memory buffer
* associated with the passed private structure or NULL if no
* such mapping exists.
* @cookie: return allocator specific cookie for a given memory buffer
* associated with the passed private structure or NULL if not
* available.
* @num_users: return the current number of users of a memory buffer;
* return 1 if the videobuf layer (or actually the driver using
* it) is the only user.
* @mmap: setup a userspace mapping for a given memory buffer under
* the provided virtual memory region.
* Required ops for USERPTR types: get_userptr, put_userptr.
* Required ops for MMAP types: alloc, put, num_users, mmap.
* Required ops for read/write access types: alloc, put, num_users, vaddr.
* Required ops for DMABUF types: attach_dmabuf, detach_dmabuf, map_dmabuf,
* unmap_dmabuf.
struct vb2_mem_ops {
void *(*alloc)(void *alloc_ctx, unsigned long size,
enum dma_data_direction dma_dir,
gfp_t gfp_flags);
void (*put)(void *buf_priv);
struct dma_buf *(*get_dmabuf)(void *buf_priv, unsigned long flags);
void *(*get_userptr)(void *alloc_ctx, unsigned long vaddr,
unsigned long size,
enum dma_data_direction dma_dir);
void (*put_userptr)(void *buf_priv);
void (*prepare)(void *buf_priv);
void (*finish)(void *buf_priv);
void *(*attach_dmabuf)(void *alloc_ctx, struct dma_buf *dbuf,
unsigned long size,
enum dma_data_direction dma_dir);
void (*detach_dmabuf)(void *buf_priv);
int (*map_dmabuf)(void *buf_priv);
void (*unmap_dmabuf)(void *buf_priv);
void *(*vaddr)(void *buf_priv);
void *(*cookie)(void *buf_priv);
unsigned int (*num_users)(void *buf_priv);
int (*mmap)(void *buf_priv, struct vm_area_struct *vma);
* struct vb2_plane - plane information
* @mem_priv: private data with this plane
* @dbuf: dma_buf - shared buffer object
* @dbuf_mapped: flag to show whether dbuf is mapped or not
* @bytesused: number of bytes occupied by data in the plane (payload)
* @length: size of this plane (NOT the payload) in bytes
* @min_length: minimum required size of this plane (NOT the payload) in bytes.
* @length is always greater or equal to @min_length.
* @offset: when memory in the associated struct vb2_buffer is
* VB2_MEMORY_MMAP, equals the offset from the start of
* the device memory for this plane (or is a "cookie" that
* should be passed to mmap() called on the video node)
* @userptr: when memory is VB2_MEMORY_USERPTR, a userspace pointer
* pointing to this plane
* @fd: when memory is VB2_MEMORY_DMABUF, a userspace file
* descriptor associated with this plane
* @m: Union with memtype-specific data (@offset, @userptr or
* @fd).
* @data_offset: offset in the plane to the start of data; usually 0,
* unless there is a header in front of the data
* Should contain enough information to be able to cover all the fields
* of struct v4l2_plane at videodev2.h
struct vb2_plane {
void *mem_priv;
struct dma_buf *dbuf;
unsigned int dbuf_mapped;
unsigned int bytesused;
unsigned int length;
unsigned int min_length;
union {
unsigned int offset;
unsigned long userptr;
int fd;
} m;
unsigned int data_offset;
* enum vb2_io_modes - queue access methods
* @VB2_MMAP: driver supports MMAP with streaming API
* @VB2_USERPTR: driver supports USERPTR with streaming API
* @VB2_READ: driver supports read() style access
* @VB2_WRITE: driver supports write() style access
* @VB2_DMABUF: driver supports DMABUF with streaming API
enum vb2_io_modes {
VB2_MMAP = (1 << 0),
VB2_USERPTR = (1 << 1),
VB2_READ = (1 << 2),
VB2_WRITE = (1 << 3),
VB2_DMABUF = (1 << 4),
* enum vb2_buffer_state - current video buffer state
* @VB2_BUF_STATE_DEQUEUED: buffer under userspace control
* @VB2_BUF_STATE_PREPARING: buffer is being prepared in videobuf
* @VB2_BUF_STATE_PREPARED: buffer prepared in videobuf and by the driver
* @VB2_BUF_STATE_QUEUED: buffer queued in videobuf, but not in driver
* @VB2_BUF_STATE_REQUEUEING: re-queue a buffer to the driver
* @VB2_BUF_STATE_ACTIVE: buffer queued in driver and possibly used
* in a hardware operation
* @VB2_BUF_STATE_DONE: buffer returned from driver to videobuf, but
* not yet dequeued to userspace
* @VB2_BUF_STATE_ERROR: same as above, but the operation on the buffer
* has ended with an error, which will be reported
* to the userspace when it is dequeued
enum vb2_buffer_state {
struct vb2_queue;
* struct vb2_buffer - represents a video buffer
* @vb2_queue: the queue to which this driver belongs
* @index: id number of the buffer
* @type: buffer type
* @memory: the method, in which the actual data is passed
* @num_planes: number of planes in the buffer
* on an internal driver queue
* @planes: private per-plane information; do not change
* @timestamp: frame timestamp in ns
struct vb2_buffer {
struct vb2_queue *vb2_queue;
unsigned int index;
unsigned int type;
unsigned int memory;
unsigned int num_planes;
struct vb2_plane planes[VB2_MAX_PLANES];
u64 timestamp;
/* private: internal use only
* state: current buffer state; do not change
* queued_entry: entry on the queued buffers list, which holds
* all buffers queued from userspace
* done_entry: entry on the list that stores all buffers ready
* to be dequeued to userspace
enum vb2_buffer_state state;
struct list_head queued_entry;
struct list_head done_entry;
* Counters for how often these buffer-related ops are
* called. Used to check for unbalanced ops.
u32 cnt_mem_alloc;
u32 cnt_mem_put;
u32 cnt_mem_get_dmabuf;
u32 cnt_mem_get_userptr;
u32 cnt_mem_put_userptr;
u32 cnt_mem_prepare;
u32 cnt_mem_finish;
u32 cnt_mem_attach_dmabuf;
u32 cnt_mem_detach_dmabuf;
u32 cnt_mem_map_dmabuf;
u32 cnt_mem_unmap_dmabuf;
u32 cnt_mem_vaddr;
u32 cnt_mem_cookie;
u32 cnt_mem_num_users;
u32 cnt_mem_mmap;
u32 cnt_buf_init;
u32 cnt_buf_prepare;
u32 cnt_buf_finish;
u32 cnt_buf_cleanup;
u32 cnt_buf_queue;
/* This counts the number of calls to vb2_buffer_done() */
u32 cnt_buf_done;
* struct vb2_ops - driver-specific callbacks
* @queue_setup: called from VIDIOC_REQBUFS and VIDIOC_CREATE_BUFS
* handlers before memory allocation. It can be called
* twice: if the original number of requested buffers
* could not be allocated, then it will be called a
* second time with the actually allocated number of
* buffers to verify if that is OK.
* The driver should return the required number of buffers
* in *num_buffers, the required number of planes per
* buffer in *num_planes, the size of each plane should be
* set in the sizes[] array and optional per-plane
* allocator specific context in the alloc_ctxs[] array.
* When called from VIDIOC_REQBUFS, *num_planes == 0, the
* driver has to use the currently configured format to
* determine the plane sizes and *num_buffers is the total
* number of buffers that are being allocated. When called
* from VIDIOC_CREATE_BUFS, *num_planes != 0 and it
* describes the requested number of planes and sizes[]
* contains the requested plane sizes. If either
* *num_planes or the requested sizes are invalid callback
* must return -EINVAL. In this case *num_buffers are
* being allocated additionally to q->num_buffers.
* @wait_prepare: release any locks taken while calling vb2 functions;
* it is called before an ioctl needs to wait for a new
* buffer to arrive; required to avoid a deadlock in
* blocking access type.
* @wait_finish: reacquire all locks released in the previous callback;
* required to continue operation after sleeping while
* waiting for a new buffer to arrive.
* @buf_init: called once after allocating a buffer (in MMAP case)
* or after acquiring a new USERPTR buffer; drivers may
* perform additional buffer-related initialization;
* initialization failure (return != 0) will prevent
* queue setup from completing successfully; optional.
* @buf_prepare: called every time the buffer is queued from userspace
* and from the VIDIOC_PREPARE_BUF ioctl; drivers may
* perform any initialization required before each
* hardware operation in this callback; drivers can
* access/modify the buffer here as it is still synced for
* the CPU; drivers that support VIDIOC_CREATE_BUFS must
* also validate the buffer size; if an error is returned,
* the buffer will not be queued in driver; optional.
* @buf_finish: called before every dequeue of the buffer back to
* userspace; the buffer is synced for the CPU, so drivers
* can access/modify the buffer contents; drivers may
* perform any operations required before userspace
* accesses the buffer; optional. The buffer state can be
* one of the following: DONE and ERROR occur while
* streaming is in progress, and the PREPARED state occurs
* when the queue has been canceled and all pending
* buffers are being returned to their default DEQUEUED
* state. Typically you only have to do something if the
* state is VB2_BUF_STATE_DONE, since in all other cases
* the buffer contents will be ignored anyway.
* @buf_cleanup: called once before the buffer is freed; drivers may
* perform any additional cleanup; optional.
* @start_streaming: called once to enter 'streaming' state; the driver may
* receive buffers with @buf_queue callback before
* @start_streaming is called; the driver gets the number
* of already queued buffers in count parameter; driver
* can return an error if hardware fails, in that case all
* buffers that have been already given by the @buf_queue
* callback are to be returned by the driver by calling
* @vb2_buffer_done(VB2_BUF_STATE_QUEUED).
* If you need a minimum number of buffers before you can
* start streaming, then set @min_buffers_needed in the
* vb2_queue structure. If that is non-zero then
* start_streaming won't be called until at least that
* many buffers have been queued up by userspace.
* @stop_streaming: called when 'streaming' state must be disabled; driver
* should stop any DMA transactions or wait until they
* finish and give back all buffers it got from buf_queue()
* callback by calling @vb2_buffer_done() with either
* vb2_wait_for_all_buffers() function
* @buf_queue: passes buffer vb to the driver; driver may start
* hardware operation on this buffer; driver should give
* the buffer back by calling vb2_buffer_done() function;
* it is allways called after calling STREAMON ioctl;
* might be called before start_streaming callback if user
* pre-queued buffers before calling STREAMON.
struct vb2_ops {
int (*queue_setup)(struct vb2_queue *q,
unsigned int *num_buffers, unsigned int *num_planes,
unsigned int sizes[], void *alloc_ctxs[]);
void (*wait_prepare)(struct vb2_queue *q);
void (*wait_finish)(struct vb2_queue *q);
int (*buf_init)(struct vb2_buffer *vb);
int (*buf_prepare)(struct vb2_buffer *vb);
void (*buf_finish)(struct vb2_buffer *vb);
void (*buf_cleanup)(struct vb2_buffer *vb);
int (*start_streaming)(struct vb2_queue *q, unsigned int count);
void (*stop_streaming)(struct vb2_queue *q);
void (*buf_queue)(struct vb2_buffer *vb);
* struct vb2_ops - driver-specific callbacks
* @fill_user_buffer: given a vb2_buffer fill in the userspace structure.
* For V4L2 this is a struct v4l2_buffer.
* @fill_vb2_buffer: given a userspace structure, fill in the vb2_buffer.
* If the userspace structure is invalid, then this op
* will return an error.
* @copy_timestamp: copy the timestamp from a userspace structure to
* the vb2_buffer struct.
struct vb2_buf_ops {
void (*fill_user_buffer)(struct vb2_buffer *vb, void *pb);
int (*fill_vb2_buffer)(struct vb2_buffer *vb, const void *pb,
struct vb2_plane *planes);
void (*copy_timestamp)(struct vb2_buffer *vb, const void *pb);
* struct vb2_queue - a videobuf queue
* @type: private buffer type whose content is defined by the vb2-core
* caller. For example, for V4L2, it should match
* the V4L2_BUF_TYPE_* in include/uapi/linux/videodev2.h
* @io_modes: supported io methods (see vb2_io_modes enum)
* @fileio_read_once: report EOF after reading the first buffer
* @fileio_write_immediately: queue buffer after each write() call
* @allow_zero_bytesused: allow bytesused == 0 to be passed to the driver
* @lock: pointer to a mutex that protects the vb2_queue struct. The
* driver can set this to a mutex to let the v4l2 core serialize
* the queuing ioctls. If the driver wants to handle locking
* itself, then this should be set to NULL. This lock is not used
* by the videobuf2 core API.
* @owner: The filehandle that 'owns' the buffers, i.e. the filehandle
* that called reqbufs, create_buffers or started fileio.
* This field is not used by the videobuf2 core API, but it allows
* drivers to easily associate an owner filehandle with the queue.
* @ops: driver-specific callbacks
* @mem_ops: memory allocator specific callbacks
* @buf_ops: callbacks to deliver buffer information
* between user-space and kernel-space
* @drv_priv: driver private data
* @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)
* will be used for v4l2.
* @timestamp_flags: Timestamp flags; V4L2_BUF_FLAG_TIMESTAMP_* and
* @gfp_flags: additional gfp flags used when allocating the buffers.
* Typically this is 0, but it may be e.g. GFP_DMA or __GFP_DMA32
* to force the buffer allocation to a specific memory zone.
* @min_buffers_needed: the minimum number of buffers needed before
* start_streaming() can be called. Used when a DMA engine
* cannot be started unless at least this number of buffers
* have been queued into the driver.
* Private elements (won't appear at the DocBook):
* @mmap_lock: private mutex used when buffers are allocated/freed/mmapped
* @memory: current memory type used
* @bufs: videobuf buffer structures
* @num_buffers: number of allocated/used buffers
* @queued_list: list of buffers currently queued from userspace
* @queued_count: number of buffers queued and ready for streaming.
* @owned_by_drv_count: number of buffers owned by the driver
* @done_list: list of buffers ready to be dequeued to userspace
* @done_lock: lock to protect done_list list
* @done_wq: waitqueue for processes waiting for buffers ready to be dequeued
* @alloc_ctx: memory type/allocator-specific contexts for each plane
* @streaming: current streaming state
* @start_streaming_called: start_streaming() was called successfully and we
* started streaming.
* @error: a fatal error occurred on the queue
* @waiting_for_buffers: used in poll() to check if vb2 is still waiting for
* buffers. Only set for capture queues if qbuf has not yet been
* called since poll() needs to return POLLERR in that situation.
* @is_multiplanar: set if buffer type is multiplanar
* @is_output: set if buffer type is output
* @copy_timestamp: set if vb2-core should set timestamps
* @last_buffer_dequeued: used in poll() and DQBUF to immediately return if the
* last decoded buffer was already dequeued. Set for capture queues
* when a buffer with the V4L2_BUF_FLAG_LAST is dequeued.
* @fileio: file io emulator internal data, used only if emulator is active
* @threadio: thread io internal data, used only if thread is active
struct vb2_queue {
unsigned int type;
unsigned int io_modes;
unsigned fileio_read_once:1;
unsigned fileio_write_immediately:1;
unsigned allow_zero_bytesused:1;
struct mutex *lock;
void *owner;
const struct vb2_ops *ops;
const struct vb2_mem_ops *mem_ops;
const struct vb2_buf_ops *buf_ops;
void *drv_priv;
unsigned int buf_struct_size;
u32 timestamp_flags;
gfp_t gfp_flags;
u32 min_buffers_needed;
/* private: internal use only */
struct mutex mmap_lock;
unsigned int memory;
struct vb2_buffer *bufs[VB2_MAX_FRAME];
unsigned int num_buffers;
struct list_head queued_list;
unsigned int queued_count;
atomic_t owned_by_drv_count;
struct list_head done_list;
spinlock_t done_lock;
wait_queue_head_t done_wq;
void *alloc_ctx[VB2_MAX_PLANES];
unsigned int streaming:1;
unsigned int start_streaming_called:1;
unsigned int error:1;
unsigned int waiting_for_buffers:1;
unsigned int is_multiplanar:1;
unsigned int is_output:1;
unsigned int copy_timestamp:1;
unsigned int last_buffer_dequeued:1;
struct vb2_fileio_data *fileio;
struct vb2_threadio_data *threadio;
* Counters for how often these queue-related ops are
* called. Used to check for unbalanced ops.
u32 cnt_queue_setup;
u32 cnt_wait_prepare;
u32 cnt_wait_finish;
u32 cnt_start_streaming;
u32 cnt_stop_streaming;
void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no);
void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no);
void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state);
void vb2_discard_done(struct vb2_queue *q);
int vb2_wait_for_all_buffers(struct vb2_queue *q);
void vb2_core_querybuf(struct vb2_queue *q, unsigned int index, void *pb);
int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
unsigned int *count);
int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
unsigned int *count, unsigned requested_planes,
const unsigned int requested_sizes[]);
int vb2_core_prepare_buf(struct vb2_queue *q, unsigned int index, void *pb);
int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb);
int vb2_core_dqbuf(struct vb2_queue *q, void *pb, bool nonblocking);
int vb2_core_streamon(struct vb2_queue *q, unsigned int type);
int vb2_core_streamoff(struct vb2_queue *q, unsigned int type);
int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type,
unsigned int index, unsigned int plane, unsigned int flags);
int vb2_core_queue_init(struct vb2_queue *q);
void vb2_core_queue_release(struct vb2_queue *q);
void vb2_queue_error(struct vb2_queue *q);
int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma);
#ifndef CONFIG_MMU
unsigned long vb2_get_unmapped_area(struct vb2_queue *q,
unsigned long addr,
unsigned long len,
unsigned long pgoff,
unsigned long flags);
unsigned int vb2_core_poll(struct vb2_queue *q, struct file *file,
poll_table *wait);
size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count,
loff_t *ppos, int nonblock);
size_t vb2_write(struct vb2_queue *q, const char __user *data, size_t count,
loff_t *ppos, int nonblock);
* vb2_thread_fnc - callback function for use with vb2_thread
* This is called whenever a buffer is dequeued in the thread.
typedef int (*vb2_thread_fnc)(struct vb2_buffer *vb, void *priv);
* vb2_thread_start() - start a thread for the given queue.
* @q: videobuf queue
* @fnc: callback function
* @priv: priv pointer passed to the callback function
* @thread_name:the name of the thread. This will be prefixed with "vb2-".
* This starts a thread that will queue and dequeue until an error occurs
* or @vb2_thread_stop is called.
* This function should not be used for anything else but the videobuf2-dvb
* support. If you think you have another good use-case for this, then please
* contact the linux-media mailinglist first.
int vb2_thread_start(struct vb2_queue *q, vb2_thread_fnc fnc, void *priv,
const char *thread_name);
* vb2_thread_stop() - stop the thread for the given queue.
* @q: videobuf queue
int vb2_thread_stop(struct vb2_queue *q);
* vb2_is_streaming() - return streaming status of the queue
* @q: videobuf queue
static inline bool vb2_is_streaming(struct vb2_queue *q)
return q->streaming;
* vb2_fileio_is_active() - return true if fileio is active.
* @q: videobuf queue
* This returns true if read() or write() is used to stream the data
* as opposed to stream I/O. This is almost never an important distinction,
* except in rare cases. One such case is that using read() or write() to
* stream a format using V4L2_FIELD_ALTERNATE is not allowed since there
* is no way you can pass the field information of each buffer to/from
* userspace. A driver that supports this field format should check for
* this in the queue_setup op and reject it if this function returns true.
static inline bool vb2_fileio_is_active(struct vb2_queue *q)
return q->fileio;
* vb2_is_busy() - return busy status of the queue
* @q: videobuf queue
* This function checks if queue has any buffers allocated.
static inline bool vb2_is_busy(struct vb2_queue *q)
return (q->num_buffers > 0);
* vb2_get_drv_priv() - return driver private data associated with the queue
* @q: videobuf queue
static inline void *vb2_get_drv_priv(struct vb2_queue *q)
return q->drv_priv;
* vb2_set_plane_payload() - set bytesused for the plane plane_no
* @vb: buffer for which plane payload should be set
* @plane_no: plane number for which payload should be set
* @size: payload in bytes
static inline void vb2_set_plane_payload(struct vb2_buffer *vb,
unsigned int plane_no, unsigned long size)
if (plane_no < vb->num_planes)
vb->planes[plane_no].bytesused = size;
* vb2_get_plane_payload() - get bytesused for the plane plane_no
* @vb: buffer for which plane payload should be set
* @plane_no: plane number for which payload should be set
static inline unsigned long vb2_get_plane_payload(struct vb2_buffer *vb,
unsigned int plane_no)
if (plane_no < vb->num_planes)
return vb->planes[plane_no].bytesused;
return 0;
* vb2_plane_size() - return plane size in bytes
* @vb: buffer for which plane size should be returned
* @plane_no: plane number for which size should be returned
static inline unsigned long
vb2_plane_size(struct vb2_buffer *vb, unsigned int plane_no)
if (plane_no < vb->num_planes)
return vb->planes[plane_no].length;
return 0;
* vb2_start_streaming_called() - return streaming status of driver
* @q: videobuf queue
static inline bool vb2_start_streaming_called(struct vb2_queue *q)
return q->start_streaming_called;
* vb2_clear_last_buffer_dequeued() - clear last buffer dequeued flag of queue
* @q: videobuf queue
static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue *q)
q->last_buffer_dequeued = false;
* The following functions are not part of the vb2 core API, but are useful
* functions for videobuf2-*.
bool vb2_buffer_in_use(struct vb2_queue *q, struct vb2_buffer *vb);
int vb2_verify_memory_type(struct vb2_queue *q,
enum vb2_memory memory, unsigned int type);
#endif /* _MEDIA_VIDEOBUF2_CORE_H */