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Diffstat (limited to 'include/media/videobuf2-v4l2.h')
| -rw-r--r-- | include/media/videobuf2-v4l2.h | 390 |
1 files changed, 390 insertions, 0 deletions
diff --git a/include/media/videobuf2-v4l2.h b/include/media/videobuf2-v4l2.h new file mode 100644 index 0000000000..5a84588785 --- /dev/null +++ b/include/media/videobuf2-v4l2.h @@ -0,0 +1,390 @@ +/* + * 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 */ |