290 lines
9.8 KiB
C
290 lines
9.8 KiB
C
/*
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* videobuf2-v4l2.h - V4L2 driver helper framework
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*
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* Copyright (C) 2010 Samsung Electronics
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*
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* Author: Pawel Osciak <pawel@osciak.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation.
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*/
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#ifndef _MEDIA_VIDEOBUF2_V4L2_H
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#define _MEDIA_VIDEOBUF2_V4L2_H
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#include <linux/videodev2.h>
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#include <media/videobuf2-core.h>
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#if VB2_MAX_FRAME != VIDEO_MAX_FRAME
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#error VB2_MAX_FRAME != VIDEO_MAX_FRAME
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#endif
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#if VB2_MAX_PLANES != VIDEO_MAX_PLANES
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#error VB2_MAX_PLANES != VIDEO_MAX_PLANES
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#endif
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/**
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* struct vb2_v4l2_buffer - video buffer information for v4l2
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*
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* @vb2_buf: video buffer 2
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* @flags: buffer informational flags
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* @field: enum v4l2_field; field order of the image in the buffer
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* @timecode: frame timecode
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* @sequence: sequence count of this frame
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*
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* Should contain enough information to be able to cover all the fields
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* of struct v4l2_buffer at videodev2.h
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*/
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struct vb2_v4l2_buffer {
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struct vb2_buffer vb2_buf;
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__u32 flags;
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__u32 field;
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struct v4l2_timecode timecode;
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__u32 sequence;
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};
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/*
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* to_vb2_v4l2_buffer() - cast struct vb2_buffer * to struct vb2_v4l2_buffer *
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*/
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#define to_vb2_v4l2_buffer(vb) \
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container_of(vb, struct vb2_v4l2_buffer, vb2_buf)
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int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b);
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/**
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* vb2_reqbufs() - Wrapper for vb2_core_reqbufs() that also verifies
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* the memory and type values.
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*
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* @q: videobuf2 queue
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* @req: struct passed from userspace to vidioc_reqbufs handler
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* in driver
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*/
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int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req);
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/**
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* vb2_create_bufs() - Wrapper for vb2_core_create_bufs() that also verifies
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* the memory and type values.
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*
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* @q: videobuf2 queue
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* @create: creation parameters, passed from userspace to vidioc_create_bufs
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* handler in driver
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*/
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int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create);
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/**
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* vb2_prepare_buf() - Pass ownership of a buffer from userspace to the kernel
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*
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* @q: videobuf2 queue
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* @b: buffer structure passed from userspace to vidioc_prepare_buf
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* handler in driver
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*
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* Should be called from vidioc_prepare_buf ioctl handler of a driver.
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* This function:
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*
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* #) verifies the passed buffer,
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* #) calls buf_prepare callback in the driver (if provided), in which
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* driver-specific buffer initialization can be performed.
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*
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* The return values from this function are intended to be directly returned
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* from vidioc_prepare_buf handler in driver.
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*/
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int vb2_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b);
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/**
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* vb2_qbuf() - Queue a buffer from userspace
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* @q: videobuf2 queue
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* @b: buffer structure passed from userspace to VIDIOC_QBUF() handler
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* in driver
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*
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* Should be called from VIDIOC_QBUF() ioctl handler of a driver.
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*
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* This function:
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*
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* #) verifies the passed buffer,
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* #) if necessary, calls buf_prepare callback in the driver (if provided), in
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* which driver-specific buffer initialization can be performed,
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* #) if streaming is on, queues the buffer in driver by the means of buf_queue
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* callback for processing.
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*
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* The return values from this function are intended to be directly returned
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* from VIDIOC_QBUF() handler in driver.
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*/
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int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b);
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/**
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* vb2_expbuf() - Export a buffer as a file descriptor
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* @q: videobuf2 queue
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* @eb: export buffer structure passed from userspace to VIDIOC_EXPBUF()
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* handler in driver
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*
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* The return values from this function are intended to be directly returned
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* from VIDIOC_EXPBUF() handler in driver.
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*/
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int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb);
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/**
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* vb2_dqbuf() - Dequeue a buffer to the userspace
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* @q: videobuf2 queue
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* @b: buffer structure passed from userspace to VIDIOC_DQBUF() handler
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* in driver
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* @nonblocking: if true, this call will not sleep waiting for a buffer if no
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* buffers ready for dequeuing are present. Normally the driver
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* would be passing (file->f_flags & O_NONBLOCK) here
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*
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* Should be called from VIDIOC_DQBUF() ioctl handler of a driver.
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*
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* This function:
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*
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* #) verifies the passed buffer,
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* #) calls buf_finish callback in the driver (if provided), in which
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* driver can perform any additional operations that may be required before
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* returning the buffer to userspace, such as cache sync,
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* #) the buffer struct members are filled with relevant information for
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* the userspace.
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*
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* The return values from this function are intended to be directly returned
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* from VIDIOC_DQBUF() handler in driver.
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*/
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int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking);
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/**
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* vb2_streamon - start streaming
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* @q: videobuf2 queue
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* @type: type argument passed from userspace to vidioc_streamon handler
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*
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* Should be called from vidioc_streamon handler of a driver.
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*
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* This function:
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*
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* 1) verifies current state
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* 2) passes any previously queued buffers to the driver and starts streaming
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*
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* The return values from this function are intended to be directly returned
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* from vidioc_streamon handler in the driver.
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*/
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int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type);
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/**
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* vb2_streamoff - stop streaming
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* @q: videobuf2 queue
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* @type: type argument passed from userspace to vidioc_streamoff handler
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*
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* Should be called from vidioc_streamoff handler of a driver.
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*
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* This function:
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*
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* #) verifies current state,
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* #) stop streaming and dequeues any queued buffers, including those previously
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* passed to the driver (after waiting for the driver to finish).
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*
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* This call can be used for pausing playback.
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* The return values from this function are intended to be directly returned
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* from vidioc_streamoff handler in the driver
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*/
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int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type);
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/**
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* vb2_queue_init() - initialize a videobuf2 queue
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* @q: videobuf2 queue; this structure should be allocated in driver
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*
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* The vb2_queue structure should be allocated by the driver. The driver is
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* responsible of clearing it's content and setting initial values for some
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* required entries before calling this function.
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* q->ops, q->mem_ops, q->type and q->io_modes are mandatory. Please refer
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* to the struct vb2_queue description in include/media/videobuf2-core.h
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* for more information.
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*/
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int __must_check vb2_queue_init(struct vb2_queue *q);
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/**
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* vb2_queue_release() - stop streaming, release the queue and free memory
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* @q: videobuf2 queue
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*
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* This function stops streaming and performs necessary clean ups, including
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* freeing video buffer memory. The driver is responsible for freeing
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* the vb2_queue structure itself.
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*/
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void vb2_queue_release(struct vb2_queue *q);
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/**
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* vb2_poll() - implements poll userspace operation
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* @q: videobuf2 queue
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* @file: file argument passed to the poll file operation handler
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* @wait: wait argument passed to the poll file operation handler
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*
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* This function implements poll file operation handler for a driver.
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* For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will
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* be informed that the file descriptor of a video device is available for
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* reading.
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* For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor
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* will be reported as available for writing.
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*
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* If the driver uses struct v4l2_fh, then vb2_poll() will also check for any
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* pending events.
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*
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* The return values from this function are intended to be directly returned
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* from poll handler in driver.
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*/
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unsigned int vb2_poll(struct vb2_queue *q, struct file *file,
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poll_table *wait);
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/*
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* The following functions are not part of the vb2 core API, but are simple
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* helper functions that you can use in your struct v4l2_file_operations,
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* struct v4l2_ioctl_ops and struct vb2_ops. They will serialize if vb2_queue->lock
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* or video_device->lock is set, and they will set and test vb2_queue->owner
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* to check if the calling filehandle is permitted to do the queuing operation.
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*/
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/* struct v4l2_ioctl_ops helpers */
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int vb2_ioctl_reqbufs(struct file *file, void *priv,
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struct v4l2_requestbuffers *p);
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int vb2_ioctl_create_bufs(struct file *file, void *priv,
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struct v4l2_create_buffers *p);
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int vb2_ioctl_prepare_buf(struct file *file, void *priv,
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struct v4l2_buffer *p);
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int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p);
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int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p);
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int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p);
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int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i);
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int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i);
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int vb2_ioctl_expbuf(struct file *file, void *priv,
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struct v4l2_exportbuffer *p);
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/* struct v4l2_file_operations helpers */
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int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma);
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int vb2_fop_release(struct file *file);
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int _vb2_fop_release(struct file *file, struct mutex *lock);
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ssize_t vb2_fop_write(struct file *file, const char __user *buf,
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size_t count, loff_t *ppos);
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ssize_t vb2_fop_read(struct file *file, char __user *buf,
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size_t count, loff_t *ppos);
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unsigned int vb2_fop_poll(struct file *file, poll_table *wait);
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#ifndef CONFIG_MMU
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unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr,
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unsigned long len, unsigned long pgoff, unsigned long flags);
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#endif
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/**
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* vb2_ops_wait_prepare - helper function to lock a struct &vb2_queue
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*
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* @vq: pointer to struct vb2_queue
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*
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* ..note:: only use if vq->lock is non-NULL.
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*/
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void vb2_ops_wait_prepare(struct vb2_queue *vq);
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/**
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* vb2_ops_wait_finish - helper function to unlock a struct &vb2_queue
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*
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* @vq: pointer to struct vb2_queue
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*
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* ..note:: only use if vq->lock is non-NULL.
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*/
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void vb2_ops_wait_finish(struct vb2_queue *vq);
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#endif /* _MEDIA_VIDEOBUF2_V4L2_H */
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