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 /*
  * 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 video_device;
 
 /**
  * struct vb2_v4l2_buffer - video buffer information for v4l2.
  *
  * @vb2_buf:    embedded struct &vb2_buffer.
  * @flags:  buffer informational flags.
  * @field:  field order of the image in the buffer, as defined by
  *      &enum v4l2_field.
  * @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
  * 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;
     __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 *
  */
 #define to_vb2_v4l2_buffer(vb) \
     container_of(vb, struct vb2_v4l2_buffer, vb2_buf)
 
 /**
  * vb2_find_timestamp() - Find buffer with given timestamp in the queue
  *
  * @q:      pointer to &struct vb2_queue with videobuf2 queue.
  * @timestamp:  the timestamp to find.
  * @start_idx:  the start index (usually 0) in the buffer array to start
  *      searching from. Note that there may be multiple buffers
  *      with the same timestamp value, so you can restart the search
  *      by setting @start_idx to the previously found index + 1.
  *
  * Returns the buffer index of the buffer with the given @timestamp, or
  * -1 if no buffer with @timestamp was found.
  */
 int vb2_find_timestamp(const struct vb2_queue *q, u64 timestamp,
                unsigned int start_idx);
 
 /**
  * vb2_find_buffer() - Find a buffer with given timestamp
  *
  * @q:      pointer to &struct vb2_queue with videobuf2 queue.
  * @timestamp:  the timestamp to find.
  *
  * Returns the buffer with the given @timestamp, or NULL if not found.
  */
 struct vb2_buffer *vb2_find_buffer(struct vb2_queue *q, u64 timestamp);
 
 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:      pointer to &struct vb2_queue with videobuf2 queue.
  * @req:    &struct v4l2_requestbuffers passed from userspace to
  *      &v4l2_ioctl_ops->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:      pointer to &struct vb2_queue with videobuf2 queue.
  * @create: creation parameters, passed from userspace to
  *      &v4l2_ioctl_ops->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:      pointer to &struct vb2_queue with videobuf2 queue.
  * @mdev:   pointer to &struct media_device, may be NULL.
  * @b:      buffer structure passed from userspace to
  *      &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver
  *
  * Should be called from &v4l2_ioctl_ops->vidioc_prepare_buf ioctl handler
  * of a driver.
  *
  * This function:
  *
  * #) verifies the passed buffer,
  * #) calls &vb2_ops->buf_prepare callback in the driver (if provided),
  *    in which driver-specific buffer initialization can be performed.
  * #) if @b->request_fd is non-zero and @mdev->ops->req_queue is set,
  *    then bind the prepared buffer to the request.
  *
  * The return values from this function are intended to be directly returned
  * from &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver.
  */
 int vb2_prepare_buf(struct vb2_queue *q, struct media_device *mdev,
             struct v4l2_buffer *b);
 
 /**
  * vb2_qbuf() - Queue a buffer from userspace
  * @q:      pointer to &struct vb2_queue with videobuf2 queue.
  * @mdev:   pointer to &struct media_device, may be NULL.
  * @b:      buffer structure passed from userspace to
  *      &v4l2_ioctl_ops->vidioc_qbuf handler in driver
  *
  * Should be called from &v4l2_ioctl_ops->vidioc_qbuf handler of a driver.
  *
  * This function:
  *
  * #) verifies the passed buffer;
  * #) if @b->request_fd is non-zero and @mdev->ops->req_queue is set,
  *    then bind the buffer to the request.
  * #) if necessary, calls &vb2_ops->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
  *    &vb2_ops->buf_queue callback for processing.
  *
  * The return values from this function are intended to be directly returned
  * from &v4l2_ioctl_ops->vidioc_qbuf handler in driver.
  */
 int vb2_qbuf(struct vb2_queue *q, struct media_device *mdev,
          struct v4l2_buffer *b);
 
 /**
  * vb2_expbuf() - Export a buffer as a file descriptor
  * @q:      pointer to &struct vb2_queue with videobuf2 queue.
  * @eb:     export buffer structure passed from userspace to
  *      &v4l2_ioctl_ops->vidioc_expbuf handler in driver
  *
  * The return values from this function are intended to be directly returned
  * from &v4l2_ioctl_ops->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:      pointer to &struct vb2_queue with videobuf2 queue.
  * @b:      buffer structure passed from userspace to
  *      &v4l2_ioctl_ops->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 &v4l2_ioctl_ops->vidioc_dqbuf ioctl handler
  * of a driver.
  *
  * This function:
  *
  * #) verifies the passed buffer;
  * #) calls &vb2_ops->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 &v4l2_ioctl_ops->vidioc_dqbuf handler in driver.
  */
 int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking);
 
 /**
  * vb2_streamon - start streaming
  * @q:      pointer to &struct vb2_queue with videobuf2 queue.
  * @type:   type argument passed from userspace to vidioc_streamon handler,
  *      as defined by &enum v4l2_buf_type.
  *
  * Should be called from &v4l2_ioctl_ops->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 &v4l2_ioctl_ops->vidioc_streamon handler in the driver.
  */
 int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type);
 
 /**
  * vb2_streamoff - stop streaming
  * @q:      pointer to &struct vb2_queue with 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:      pointer to &struct vb2_queue with videobuf2 queue.
  *
  * 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_init_name() - initialize a videobuf2 queue with a name
  * @q:      pointer to &struct vb2_queue with videobuf2 queue.
  * @name:   the queue name
  *
  * This function initializes the vb2_queue exactly like vb2_queue_init(),
  * and additionally sets the queue name. The queue name is used for logging
  * purpose, and should uniquely identify the queue within the context of the
  * device it belongs to. This is useful to attribute kernel log messages to the
  * right queue for m2m devices or other devices that handle multiple queues.
  */
 int __must_check vb2_queue_init_name(struct vb2_queue *q, const char *name);
 
 /**
  * vb2_queue_release() - stop streaming, release the queue and free memory
  * @q:      pointer to &struct vb2_queue with 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_queue_change_type() - change the type of an inactive vb2_queue
  * @q:      pointer to &struct vb2_queue with videobuf2 queue.
  * @type:   the type to change to (V4L2_BUF_TYPE_VIDEO_*)
  *
  * This function changes the type of the vb2_queue. This is only possible
  * if the queue is not busy (i.e. no buffers have been allocated).
  *
  * vb2_queue_change_type() can be used to support multiple buffer types using
  * the same queue. The driver can implement v4l2_ioctl_ops.vidioc_reqbufs and
  * v4l2_ioctl_ops.vidioc_create_bufs functions and call vb2_queue_change_type()
  * before calling vb2_ioctl_reqbufs() or vb2_ioctl_create_bufs(), and thus
  * "lock" the buffer type until the buffers have been released.
  */
 int vb2_queue_change_type(struct vb2_queue *q, unsigned int type);
 
 /**
  * vb2_poll() - implements poll userspace operation
  * @q:      pointer to &struct vb2_queue with 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.
  */
 __poll_t 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 the queue owner
  * (vb2_queue->owner) to check if the calling filehandle is permitted to do the
  * queuing operation.
  */
 
 /**
  * vb2_queue_is_busy() - check if the queue is busy
  * @q:      pointer to &struct vb2_queue with videobuf2 queue.
  * @file:   file through which the vb2 queue access is performed
  *
  * The queue is considered busy if it has an owner and the owner is not the
  * @file.
  *
  * Queue ownership is acquired and checked by some of the v4l2_ioctl_ops helpers
  * below. Drivers can also use this function directly when they need to
  * open-code ioctl handlers, for instance to add additional checks between the
  * queue ownership test and the call to the corresponding vb2 operation.
  */
 static inline bool vb2_queue_is_busy(struct vb2_queue *q, struct file *file)
 {
     return q->owner && q->owner != file->private_data;
 }
 
 /* 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);
 __poll_t 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_video_unregister_device - unregister the video device and release queue
  *
  * @vdev: pointer to &struct video_device
  *
  * If the driver uses vb2_fop_release()/_vb2_fop_release(), then it should use
  * vb2_video_unregister_device() instead of video_unregister_device().
  *
  * This function will call video_unregister_device() and then release the
  * vb2_queue if streaming is in progress. This will stop streaming and
  * this will simplify the unbind sequence since after this call all subdevs
  * will have stopped streaming as well.
  */
 void vb2_video_unregister_device(struct video_device *vdev);
 
 /**
  * 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);
 
 struct media_request;
 int vb2_request_validate(struct media_request *req);
 void vb2_request_queue(struct media_request *req);
 
 #endif /* _MEDIA_VIDEOBUF2_V4L2_H */

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