2 * videobuf2-v4l2.h - V4L2 driver helper framework
4 * Copyright (C) 2010 Samsung Electronics
6 * Author: Pawel Osciak <pawel@osciak.com>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation.
12 #ifndef _MEDIA_VIDEOBUF2_V4L2_H
13 #define _MEDIA_VIDEOBUF2_V4L2_H
15 #include <linux/videodev2.h>
16 #include <media/videobuf2-core.h>
18 #if VB2_MAX_FRAME != VIDEO_MAX_FRAME
19 #error VB2_MAX_FRAME != VIDEO_MAX_FRAME
22 #if VB2_MAX_PLANES != VIDEO_MAX_PLANES
23 #error VB2_MAX_PLANES != VIDEO_MAX_PLANES
29 * struct vb2_v4l2_buffer - video buffer information for v4l2.
31 * @vb2_buf: embedded struct &vb2_buffer.
32 * @flags: buffer informational flags.
33 * @field: field order of the image in the buffer, as defined by
35 * @timecode: frame timecode.
36 * @sequence: sequence count of this frame.
37 * @request_fd: the request_fd associated with this buffer
38 * @is_held: if true, then this capture buffer was held
39 * @planes: plane information (userptr/fd, length, bytesused, data_offset).
41 * Should contain enough information to be able to cover all the fields
42 * of &struct v4l2_buffer at ``videodev2.h``.
44 struct vb2_v4l2_buffer {
45 struct vb2_buffer vb2_buf;
49 struct v4l2_timecode timecode;
53 struct vb2_plane planes[VB2_MAX_PLANES];
56 /* VB2 V4L2 flags as set in vb2_queue.subsystem_flags */
57 #define VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF (1 << 0)
60 * to_vb2_v4l2_buffer() - cast struct vb2_buffer * to struct vb2_v4l2_buffer *
62 #define to_vb2_v4l2_buffer(vb) \
63 container_of(vb, struct vb2_v4l2_buffer, vb2_buf)
66 * vb2_find_timestamp() - Find buffer with given timestamp in the queue
68 * @q: pointer to &struct vb2_queue with videobuf2 queue.
69 * @timestamp: the timestamp to find.
70 * @start_idx: the start index (usually 0) in the buffer array to start
71 * searching from. Note that there may be multiple buffers
72 * with the same timestamp value, so you can restart the search
73 * by setting @start_idx to the previously found index + 1.
75 * Returns the buffer index of the buffer with the given @timestamp, or
76 * -1 if no buffer with @timestamp was found.
78 int vb2_find_timestamp(const struct vb2_queue *q, u64 timestamp,
79 unsigned int start_idx);
82 * vb2_find_buffer() - Find a buffer with given timestamp
84 * @q: pointer to &struct vb2_queue with videobuf2 queue.
85 * @timestamp: the timestamp to find.
87 * Returns the buffer with the given @timestamp, or NULL if not found.
89 struct vb2_buffer *vb2_find_buffer(struct vb2_queue *q, u64 timestamp);
91 int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b);
94 * vb2_reqbufs() - Wrapper for vb2_core_reqbufs() that also verifies
95 * the memory and type values.
97 * @q: pointer to &struct vb2_queue with videobuf2 queue.
98 * @req: &struct v4l2_requestbuffers passed from userspace to
99 * &v4l2_ioctl_ops->vidioc_reqbufs handler in driver.
101 int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req);
104 * vb2_create_bufs() - Wrapper for vb2_core_create_bufs() that also verifies
105 * the memory and type values.
107 * @q: pointer to &struct vb2_queue with videobuf2 queue.
108 * @create: creation parameters, passed from userspace to
109 * &v4l2_ioctl_ops->vidioc_create_bufs handler in driver
111 int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create);
114 * vb2_prepare_buf() - Pass ownership of a buffer from userspace to the kernel
116 * @q: pointer to &struct vb2_queue with videobuf2 queue.
117 * @mdev: pointer to &struct media_device, may be NULL.
118 * @b: buffer structure passed from userspace to
119 * &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver
121 * Should be called from &v4l2_ioctl_ops->vidioc_prepare_buf ioctl handler
126 * #) verifies the passed buffer,
127 * #) calls &vb2_ops->buf_prepare callback in the driver (if provided),
128 * in which driver-specific buffer initialization can be performed.
129 * #) if @b->request_fd is non-zero and @mdev->ops->req_queue is set,
130 * then bind the prepared buffer to the request.
132 * The return values from this function are intended to be directly returned
133 * from &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver.
135 int vb2_prepare_buf(struct vb2_queue *q, struct media_device *mdev,
136 struct v4l2_buffer *b);
139 * vb2_qbuf() - Queue a buffer from userspace
140 * @q: pointer to &struct vb2_queue with videobuf2 queue.
141 * @mdev: pointer to &struct media_device, may be NULL.
142 * @b: buffer structure passed from userspace to
143 * &v4l2_ioctl_ops->vidioc_qbuf handler in driver
145 * Should be called from &v4l2_ioctl_ops->vidioc_qbuf handler of a driver.
149 * #) verifies the passed buffer;
150 * #) if @b->request_fd is non-zero and @mdev->ops->req_queue is set,
151 * then bind the buffer to the request.
152 * #) if necessary, calls &vb2_ops->buf_prepare callback in the driver
153 * (if provided), in which driver-specific buffer initialization can
155 * #) if streaming is on, queues the buffer in driver by the means of
156 * &vb2_ops->buf_queue callback for processing.
158 * The return values from this function are intended to be directly returned
159 * from &v4l2_ioctl_ops->vidioc_qbuf handler in driver.
161 int vb2_qbuf(struct vb2_queue *q, struct media_device *mdev,
162 struct v4l2_buffer *b);
165 * vb2_expbuf() - Export a buffer as a file descriptor
166 * @q: pointer to &struct vb2_queue with videobuf2 queue.
167 * @eb: export buffer structure passed from userspace to
168 * &v4l2_ioctl_ops->vidioc_expbuf handler in driver
170 * The return values from this function are intended to be directly returned
171 * from &v4l2_ioctl_ops->vidioc_expbuf handler in driver.
173 int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb);
176 * vb2_dqbuf() - Dequeue a buffer to the userspace
177 * @q: pointer to &struct vb2_queue with videobuf2 queue.
178 * @b: buffer structure passed from userspace to
179 * &v4l2_ioctl_ops->vidioc_dqbuf handler in driver
180 * @nonblocking: if true, this call will not sleep waiting for a buffer if no
181 * buffers ready for dequeuing are present. Normally the driver
182 * would be passing (&file->f_flags & %O_NONBLOCK) here
184 * Should be called from &v4l2_ioctl_ops->vidioc_dqbuf ioctl handler
189 * #) verifies the passed buffer;
190 * #) calls &vb2_ops->buf_finish callback in the driver (if provided), in which
191 * driver can perform any additional operations that may be required before
192 * returning the buffer to userspace, such as cache sync;
193 * #) the buffer struct members are filled with relevant information for
196 * The return values from this function are intended to be directly returned
197 * from &v4l2_ioctl_ops->vidioc_dqbuf handler in driver.
199 int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking);
202 * vb2_streamon - start streaming
203 * @q: pointer to &struct vb2_queue with videobuf2 queue.
204 * @type: type argument passed from userspace to vidioc_streamon handler,
205 * as defined by &enum v4l2_buf_type.
207 * Should be called from &v4l2_ioctl_ops->vidioc_streamon handler of a driver.
211 * 1) verifies current state
212 * 2) passes any previously queued buffers to the driver and starts streaming
214 * The return values from this function are intended to be directly returned
215 * from &v4l2_ioctl_ops->vidioc_streamon handler in the driver.
217 int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type);
220 * vb2_streamoff - stop streaming
221 * @q: pointer to &struct vb2_queue with videobuf2 queue.
222 * @type: type argument passed from userspace to vidioc_streamoff handler
224 * Should be called from vidioc_streamoff handler of a driver.
228 * #) verifies current state,
229 * #) stop streaming and dequeues any queued buffers, including those previously
230 * passed to the driver (after waiting for the driver to finish).
232 * This call can be used for pausing playback.
233 * The return values from this function are intended to be directly returned
234 * from vidioc_streamoff handler in the driver
236 int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type);
239 * vb2_queue_init() - initialize a videobuf2 queue
240 * @q: pointer to &struct vb2_queue with videobuf2 queue.
242 * The vb2_queue structure should be allocated by the driver. The driver is
243 * responsible of clearing it's content and setting initial values for some
244 * required entries before calling this function.
245 * q->ops, q->mem_ops, q->type and q->io_modes are mandatory. Please refer
246 * to the struct vb2_queue description in include/media/videobuf2-core.h
247 * for more information.
249 int __must_check vb2_queue_init(struct vb2_queue *q);
252 * vb2_queue_init_name() - initialize a videobuf2 queue with a name
253 * @q: pointer to &struct vb2_queue with videobuf2 queue.
254 * @name: the queue name
256 * This function initializes the vb2_queue exactly like vb2_queue_init(),
257 * and additionally sets the queue name. The queue name is used for logging
258 * purpose, and should uniquely identify the queue within the context of the
259 * device it belongs to. This is useful to attribute kernel log messages to the
260 * right queue for m2m devices or other devices that handle multiple queues.
262 int __must_check vb2_queue_init_name(struct vb2_queue *q, const char *name);
265 * vb2_queue_release() - stop streaming, release the queue and free memory
266 * @q: pointer to &struct vb2_queue with videobuf2 queue.
268 * This function stops streaming and performs necessary clean ups, including
269 * freeing video buffer memory. The driver is responsible for freeing
270 * the vb2_queue structure itself.
272 void vb2_queue_release(struct vb2_queue *q);
275 * vb2_queue_change_type() - change the type of an inactive vb2_queue
276 * @q: pointer to &struct vb2_queue with videobuf2 queue.
277 * @type: the type to change to (V4L2_BUF_TYPE_VIDEO_*)
279 * This function changes the type of the vb2_queue. This is only possible
280 * if the queue is not busy (i.e. no buffers have been allocated).
282 * vb2_queue_change_type() can be used to support multiple buffer types using
283 * the same queue. The driver can implement v4l2_ioctl_ops.vidioc_reqbufs and
284 * v4l2_ioctl_ops.vidioc_create_bufs functions and call vb2_queue_change_type()
285 * before calling vb2_ioctl_reqbufs() or vb2_ioctl_create_bufs(), and thus
286 * "lock" the buffer type until the buffers have been released.
288 int vb2_queue_change_type(struct vb2_queue *q, unsigned int type);
291 * vb2_poll() - implements poll userspace operation
292 * @q: pointer to &struct vb2_queue with videobuf2 queue.
293 * @file: file argument passed to the poll file operation handler
294 * @wait: wait argument passed to the poll file operation handler
296 * This function implements poll file operation handler for a driver.
297 * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will
298 * be informed that the file descriptor of a video device is available for
300 * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor
301 * will be reported as available for writing.
303 * If the driver uses struct v4l2_fh, then vb2_poll() will also check for any
306 * The return values from this function are intended to be directly returned
307 * from poll handler in driver.
309 __poll_t vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait);
312 * The following functions are not part of the vb2 core API, but are simple
313 * helper functions that you can use in your struct v4l2_file_operations,
314 * struct v4l2_ioctl_ops and struct vb2_ops. They will serialize if vb2_queue->lock
315 * or video_device->lock is set, and they will set and test the queue owner
316 * (vb2_queue->owner) to check if the calling filehandle is permitted to do the
321 * vb2_queue_is_busy() - check if the queue is busy
322 * @q: pointer to &struct vb2_queue with videobuf2 queue.
323 * @file: file through which the vb2 queue access is performed
325 * The queue is considered busy if it has an owner and the owner is not the
328 * Queue ownership is acquired and checked by some of the v4l2_ioctl_ops helpers
329 * below. Drivers can also use this function directly when they need to
330 * open-code ioctl handlers, for instance to add additional checks between the
331 * queue ownership test and the call to the corresponding vb2 operation.
333 static inline bool vb2_queue_is_busy(struct vb2_queue *q, struct file *file)
335 return q->owner && q->owner != file->private_data;
338 /* struct v4l2_ioctl_ops helpers */
340 int vb2_ioctl_reqbufs(struct file *file, void *priv,
341 struct v4l2_requestbuffers *p);
342 int vb2_ioctl_create_bufs(struct file *file, void *priv,
343 struct v4l2_create_buffers *p);
344 int vb2_ioctl_prepare_buf(struct file *file, void *priv,
345 struct v4l2_buffer *p);
346 int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p);
347 int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p);
348 int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p);
349 int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i);
350 int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i);
351 int vb2_ioctl_expbuf(struct file *file, void *priv,
352 struct v4l2_exportbuffer *p);
354 /* struct v4l2_file_operations helpers */
356 int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma);
357 int vb2_fop_release(struct file *file);
358 int _vb2_fop_release(struct file *file, struct mutex *lock);
359 ssize_t vb2_fop_write(struct file *file, const char __user *buf,
360 size_t count, loff_t *ppos);
361 ssize_t vb2_fop_read(struct file *file, char __user *buf,
362 size_t count, loff_t *ppos);
363 __poll_t vb2_fop_poll(struct file *file, poll_table *wait);
365 unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr,
366 unsigned long len, unsigned long pgoff, unsigned long flags);
370 * vb2_video_unregister_device - unregister the video device and release queue
372 * @vdev: pointer to &struct video_device
374 * If the driver uses vb2_fop_release()/_vb2_fop_release(), then it should use
375 * vb2_video_unregister_device() instead of video_unregister_device().
377 * This function will call video_unregister_device() and then release the
378 * vb2_queue if streaming is in progress. This will stop streaming and
379 * this will simplify the unbind sequence since after this call all subdevs
380 * will have stopped streaming as well.
382 void vb2_video_unregister_device(struct video_device *vdev);
385 * vb2_ops_wait_prepare - helper function to lock a struct &vb2_queue
387 * @vq: pointer to &struct vb2_queue
389 * ..note:: only use if vq->lock is non-NULL.
391 void vb2_ops_wait_prepare(struct vb2_queue *vq);
394 * vb2_ops_wait_finish - helper function to unlock a struct &vb2_queue
396 * @vq: pointer to &struct vb2_queue
398 * ..note:: only use if vq->lock is non-NULL.
400 void vb2_ops_wait_finish(struct vb2_queue *vq);
402 struct media_request;
403 int vb2_request_validate(struct media_request *req);
404 void vb2_request_queue(struct media_request *req);
406 #endif /* _MEDIA_VIDEOBUF2_V4L2_H */