name : 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 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_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 */