linux/include/media/videobuf2-core.h
Laurent Pinchart 34ea4d4417 [media] v4l: vb2: Add a function to discard all DONE buffers
When suspending a device while a video stream is active all buffers
marked as done but not dequeued yet will be kept across suspend and
given back to userspace after resume. This will result in outdated
buffers being dequeued.

Introduce a new vb2 function to mark all done buffers as erroneous
instead, to be used by drivers at resume time.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
2014-05-25 11:37:49 -03:00

629 lines
24 KiB
C

/*
* videobuf2-core.h - V4L2 driver helper framework
*
* Copyright (C) 2010 Samsung Electronics
*
* Author: Pawel Osciak <pawel@osciak.com>
*
* 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.
*/
#ifndef _MEDIA_VIDEOBUF2_CORE_H
#define _MEDIA_VIDEOBUF2_CORE_H
#include <linux/mm_types.h>
#include <linux/mutex.h>
#include <linux/poll.h>
#include <linux/videodev2.h>
#include <linux/dma-buf.h>
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_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, 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, int write);
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, int write);
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 {
void *mem_priv;
struct dma_buf *dbuf;
unsigned int dbuf_mapped;
};
/**
* 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_fileio_flags - flags for selecting a mode of the file io emulator,
* by default the 'streaming' style is used by the file io emulator
* @VB2_FILEIO_READ_ONCE: report EOF after reading the first buffer
* @VB2_FILEIO_WRITE_IMMEDIATELY: queue buffer after each write() call
*/
enum vb2_fileio_flags {
VB2_FILEIO_READ_ONCE = (1 << 0),
VB2_FILEIO_WRITE_IMMEDIATELY = (1 << 1),
};
/**
* 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_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 {
VB2_BUF_STATE_DEQUEUED,
VB2_BUF_STATE_PREPARING,
VB2_BUF_STATE_PREPARED,
VB2_BUF_STATE_QUEUED,
VB2_BUF_STATE_ACTIVE,
VB2_BUF_STATE_DONE,
VB2_BUF_STATE_ERROR,
};
struct vb2_queue;
/**
* struct vb2_buffer - represents a video buffer
* @v4l2_buf: struct v4l2_buffer associated with this buffer; can
* be read by the driver and relevant entries can be
* changed by the driver in case of CAPTURE types
* (such as timestamp)
* @v4l2_planes: struct v4l2_planes associated with this buffer; can
* be read by the driver and relevant entries can be
* changed by the driver in case of CAPTURE types
* (such as bytesused); NOTE that even for single-planar
* types, the v4l2_planes[0] struct should be used
* instead of v4l2_buf for filling bytesused - drivers
* should use the vb2_set_plane_payload() function for that
* @vb2_queue: the queue to which this driver belongs
* @num_planes: number of planes in the buffer
* on an internal driver queue
* @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
* @planes: private per-plane information; do not change
*/
struct vb2_buffer {
struct v4l2_buffer v4l2_buf;
struct v4l2_plane v4l2_planes[VIDEO_MAX_PLANES];
struct vb2_queue *vb2_queue;
unsigned int num_planes;
/* Private: internal use only */
enum vb2_buffer_state state;
struct list_head queued_entry;
struct list_head done_entry;
struct vb2_plane planes[VIDEO_MAX_PLANES];
#ifdef CONFIG_VIDEO_ADV_DEBUG
/*
* 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;
#endif
};
/**
* struct vb2_ops - driver-specific callbacks
*
* @queue_setup: called from VIDIOC_REQBUFS and VIDIOC_CREATE_BUFS
* handlers before memory allocation, or, if
* *num_planes != 0, after the allocation to verify a
* smaller number of buffers. 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,
* fmt == NULL, the driver has to use the currently
* configured format and *num_buffers is the total number
* of buffers, that are being allocated. When called from
* VIDIOC_CREATE_BUFS, fmt != NULL and it describes the
* target frame format (if the format isn't valid the
* 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 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; 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 invalidated.
* If there were not enough queued buffers to start
* streaming, then this callback returns -ENOBUFS, and the
* vb2 core will retry calling @start_streaming when a new
* buffer is queued.
* @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; may use 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, const struct v4l2_format *fmt,
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 v4l2_fh;
/**
* struct vb2_queue - a videobuf queue
*
* @type: queue type (see V4L2_BUF_TYPE_* in linux/videodev2.h
* @io_modes: supported io methods (see vb2_io_modes enum)
* @io_flags: additional io flags (see vb2_fileio_flags enum)
* @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
* @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, so sizeof(struct vb2_buffer) will is used
* @timestamp_flags: Timestamp flags; V4L2_BUF_FLAGS_TIMESTAMP_* and
* V4L2_BUF_FLAGS_TSTAMP_SRC_*
* @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.
*
* @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.
* @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 {
enum v4l2_buf_type type;
unsigned int io_modes;
unsigned int io_flags;
struct mutex *lock;
struct v4l2_fh *owner;
const struct vb2_ops *ops;
const struct vb2_mem_ops *mem_ops;
void *drv_priv;
unsigned int buf_struct_size;
u32 timestamp_flags;
gfp_t gfp_flags;
u32 min_buffers_needed;
/* private: internal use only */
enum v4l2_memory memory;
struct vb2_buffer *bufs[VIDEO_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[VIDEO_MAX_PLANES];
unsigned int plane_sizes[VIDEO_MAX_PLANES];
unsigned int streaming:1;
unsigned int start_streaming_called:1;
struct vb2_fileio_data *fileio;
struct vb2_threadio_data *threadio;
#ifdef CONFIG_VIDEO_ADV_DEBUG
/*
* 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;
#endif
};
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);
int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b);
int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req);
int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create);
int vb2_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b);
int __must_check vb2_queue_init(struct vb2_queue *q);
void vb2_queue_release(struct vb2_queue *q);
int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b);
int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb);
int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking);
int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type);
int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type);
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);
#endif
unsigned int vb2_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->v4l2_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
* @size: payload in bytes
*/
static inline unsigned long vb2_get_plane_payload(struct vb2_buffer *vb,
unsigned int plane_no)
{
if (plane_no < vb->num_planes)
return vb->v4l2_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->v4l2_planes[plane_no].length;
return 0;
}
/*
* The following functions are not part of the vb2 core API, but are simple
* helper functions that you can use in your struct v4l2_file_operations,
* struct v4l2_ioctl_ops and struct vb2_ops. They will serialize if vb2_queue->lock
* or video_device->lock is set, and they will set and test vb2_queue->owner
* to check if the calling filehandle is permitted to do the queuing operation.
*/
/* struct v4l2_ioctl_ops helpers */
int vb2_ioctl_reqbufs(struct file *file, void *priv,
struct v4l2_requestbuffers *p);
int vb2_ioctl_create_bufs(struct file *file, void *priv,
struct v4l2_create_buffers *p);
int vb2_ioctl_prepare_buf(struct file *file, void *priv,
struct v4l2_buffer *p);
int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p);
int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p);
int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p);
int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i);
int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i);
int vb2_ioctl_expbuf(struct file *file, void *priv,
struct v4l2_exportbuffer *p);
/* struct v4l2_file_operations helpers */
int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma);
int vb2_fop_release(struct file *file);
int _vb2_fop_release(struct file *file, struct mutex *lock);
ssize_t vb2_fop_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos);
ssize_t vb2_fop_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos);
unsigned int vb2_fop_poll(struct file *file, poll_table *wait);
#ifndef CONFIG_MMU
unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr,
unsigned long len, unsigned long pgoff, unsigned long flags);
#endif
/* struct vb2_ops helpers, only use if vq->lock is non-NULL. */
void vb2_ops_wait_prepare(struct vb2_queue *vq);
void vb2_ops_wait_finish(struct vb2_queue *vq);
#endif /* _MEDIA_VIDEOBUF2_CORE_H */