Release 4.12 include/media/videobuf2-v4l2.h
/*
* videobuf2-v4l2.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_V4L2_H
#define _MEDIA_VIDEOBUF2_V4L2_H
#include <linux/videodev2.h>
#include <media/videobuf2-core.h>
#if VB2_MAX_FRAME != VIDEO_MAX_FRAME
#error VB2_MAX_FRAME != VIDEO_MAX_FRAME
#endif
#if VB2_MAX_PLANES != VIDEO_MAX_PLANES
#error VB2_MAX_PLANES != VIDEO_MAX_PLANES
#endif
/**
* struct vb2_v4l2_buffer - video buffer information for v4l2
*
* @vb2_buf: video buffer 2
* @flags: buffer informational flags
* @field: enum v4l2_field; field order of the image in the buffer
* @timecode: frame timecode
* @sequence: sequence count of this frame
*
* Should contain enough information to be able to cover all the fields
* of struct v4l2_buffer at videodev2.h
*/
struct vb2_v4l2_buffer {
struct vb2_buffer vb2_buf;
__u32 flags;
__u32 field;
struct v4l2_timecode timecode;
__u32 sequence;
};
/*
* to_vb2_v4l2_buffer() - cast struct vb2_buffer * to struct vb2_v4l2_buffer *
*/
#define to_vb2_v4l2_buffer(vb) \
container_of(vb, struct vb2_v4l2_buffer, vb2_buf)
int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b);
/**
* vb2_reqbufs() - Wrapper for vb2_core_reqbufs() that also verifies
* the memory and type values.
*
* @q: videobuf2 queue
* @req: struct passed from userspace to vidioc_reqbufs handler
* in driver
*/
int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req);
/**
* vb2_create_bufs() - Wrapper for vb2_core_create_bufs() that also verifies
* the memory and type values.
*
* @q: videobuf2 queue
* @create: creation parameters, passed from userspace to vidioc_create_bufs
* handler in driver
*/
int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create);
/**
* vb2_prepare_buf() - Pass ownership of a buffer from userspace to the kernel
*
* @q: videobuf2 queue
* @b: buffer structure passed from userspace to vidioc_prepare_buf
* handler in driver
*
* Should be called from vidioc_prepare_buf ioctl handler of a driver.
* This function:
*
* #) verifies the passed buffer,
* #) calls buf_prepare callback in the driver (if provided), in which
* driver-specific buffer initialization can be performed.
*
* The return values from this function are intended to be directly returned
* from vidioc_prepare_buf handler in driver.
*/
int vb2_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b);
/**
* vb2_qbuf() - Queue a buffer from userspace
* @q: videobuf2 queue
* @b: buffer structure passed from userspace to VIDIOC_QBUF() handler
* in driver
*
* Should be called from VIDIOC_QBUF() ioctl handler of a driver.
*
* This function:
*
* #) verifies the passed buffer,
* #) if necessary, calls buf_prepare callback in the driver (if provided), in
* which driver-specific buffer initialization can be performed,
* #) if streaming is on, queues the buffer in driver by the means of buf_queue
* callback for processing.
*
* The return values from this function are intended to be directly returned
* from VIDIOC_QBUF() handler in driver.
*/
int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b);
/**
* vb2_expbuf() - Export a buffer as a file descriptor
* @q: videobuf2 queue
* @eb: export buffer structure passed from userspace to VIDIOC_EXPBUF()
* handler in driver
*
* The return values from this function are intended to be directly returned
* from VIDIOC_EXPBUF() handler in driver.
*/
int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb);
/**
* vb2_dqbuf() - Dequeue a buffer to the userspace
* @q: videobuf2 queue
* @b: buffer structure passed from userspace to VIDIOC_DQBUF() handler
* in driver
* @nonblocking: if true, this call will not sleep waiting for a buffer if no
* buffers ready for dequeuing are present. Normally the driver
* would be passing (file->f_flags & O_NONBLOCK) here
*
* Should be called from VIDIOC_DQBUF() ioctl handler of a driver.
*
* This function:
*
* #) verifies the passed buffer,
* #) calls buf_finish callback in the driver (if provided), in which
* driver can perform any additional operations that may be required before
* returning the buffer to userspace, such as cache sync,
* #) the buffer struct members are filled with relevant information for
* the userspace.
*
* The return values from this function are intended to be directly returned
* from VIDIOC_DQBUF() handler in driver.
*/
int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking);
/**
* vb2_streamon - start streaming
* @q: videobuf2 queue
* @type: type argument passed from userspace to vidioc_streamon handler
*
* Should be called from vidioc_streamon handler of a driver.
*
* This function:
*
* 1) verifies current state
* 2) passes any previously queued buffers to the driver and starts streaming
*
* The return values from this function are intended to be directly returned
* from vidioc_streamon handler in the driver.
*/
int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type);
/**
* vb2_streamoff - stop streaming
* @q: videobuf2 queue
* @type: type argument passed from userspace to vidioc_streamoff handler
*
* Should be called from vidioc_streamoff handler of a driver.
*
* This function:
*
* #) verifies current state,
* #) stop streaming and dequeues any queued buffers, including those previously
* passed to the driver (after waiting for the driver to finish).
*
* This call can be used for pausing playback.
* The return values from this function are intended to be directly returned
* from vidioc_streamoff handler in the driver
*/
int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type);
/**
* vb2_queue_init() - initialize a videobuf2 queue
* @q: videobuf2 queue; this structure should be allocated in driver
*
* The vb2_queue structure should be allocated by the driver. The driver is
* responsible of clearing it's content and setting initial values for some
* required entries before calling this function.
* q->ops, q->mem_ops, q->type and q->io_modes are mandatory. Please refer
* to the struct vb2_queue description in include/media/videobuf2-core.h
* for more information.
*/
int __must_check vb2_queue_init(struct vb2_queue *q);
/**
* vb2_queue_release() - stop streaming, release the queue and free memory
* @q: videobuf2 queue
*
* This function stops streaming and performs necessary clean ups, including
* freeing video buffer memory. The driver is responsible for freeing
* the vb2_queue structure itself.
*/
void vb2_queue_release(struct vb2_queue *q);
/**
* vb2_poll() - implements poll userspace operation
* @q: videobuf2 queue
* @file: file argument passed to the poll file operation handler
* @wait: wait argument passed to the poll file operation handler
*
* This function implements poll file operation handler for a driver.
* For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will
* be informed that the file descriptor of a video device is available for
* reading.
* For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor
* will be reported as available for writing.
*
* If the driver uses struct v4l2_fh, then vb2_poll() will also check for any
* pending events.
*
* The return values from this function are intended to be directly returned
* from poll handler in driver.
*/
unsigned int vb2_poll(struct vb2_queue *q, struct file *file,
poll_table *wait);
/*
* 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
/**
* vb2_ops_wait_prepare - helper function to lock a struct &vb2_queue
*
* @vq: pointer to struct vb2_queue
*
* ..note:: only use if vq->lock is non-NULL.
*/
void vb2_ops_wait_prepare(struct vb2_queue *vq);
/**
* vb2_ops_wait_finish - helper function to unlock a struct &vb2_queue
*
* @vq: pointer to struct vb2_queue
*
* ..note:: only use if vq->lock is non-NULL.
*/
void vb2_ops_wait_finish(struct vb2_queue *vq);
#endif /* _MEDIA_VIDEOBUF2_V4L2_H */
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