1/*
2 * videobuf2-v4l2.h - V4L2 driver helper framework
3 *
4 * Copyright (C) 2010 Samsung Electronics
5 *
6 * Author: Pawel Osciak <pawel@osciak.com>
7 *
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.
11 */
12#ifndef _MEDIA_VIDEOBUF2_V4L2_H
13#define _MEDIA_VIDEOBUF2_V4L2_H
14
15#include <linux/videodev2.h>
16#include <media/videobuf2-core.h>
17
18#if VB2_MAX_FRAME != VIDEO_MAX_FRAME
19#error VB2_MAX_FRAME != VIDEO_MAX_FRAME
20#endif
21
22#if VB2_MAX_PLANES != VIDEO_MAX_PLANES
23#error VB2_MAX_PLANES != VIDEO_MAX_PLANES
24#endif
25
26struct video_device;
27
28/**
29 * struct vb2_v4l2_buffer - video buffer information for v4l2.
30 *
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
34 * &enum v4l2_field.
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).
40 *
41 * Should contain enough information to be able to cover all the fields
42 * of &struct v4l2_buffer at ``videodev2.h``.
43 */
44struct vb2_v4l2_buffer {
45 struct vb2_buffer vb2_buf;
46
47 __u32 flags;
48 __u32 field;
49 struct v4l2_timecode timecode;
50 __u32 sequence;
51 __s32 request_fd;
52 bool is_held;
53 struct vb2_plane planes[VB2_MAX_PLANES];
54};
55
56/* VB2 V4L2 flags as set in vb2_queue.subsystem_flags */
57#define VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF (1 << 0)
58
59/*
60 * to_vb2_v4l2_buffer() - cast struct vb2_buffer * to struct vb2_v4l2_buffer *
61 */
62#define to_vb2_v4l2_buffer(vb) \
63 container_of(vb, struct vb2_v4l2_buffer, vb2_buf)
64
65/**
66 * vb2_find_buffer() - Find a buffer with given timestamp
67 *
68 * @q: pointer to &struct vb2_queue with videobuf2 queue.
69 * @timestamp: the timestamp to find.
70 *
71 * Returns the buffer with the given @timestamp, or NULL if not found.
72 */
73struct vb2_buffer *vb2_find_buffer(struct vb2_queue *q, u64 timestamp);
74
75int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b);
76
77/**
78 * vb2_reqbufs() - Wrapper for vb2_core_reqbufs() that also verifies
79 * the memory and type values.
80 *
81 * @q: pointer to &struct vb2_queue with videobuf2 queue.
82 * @req: &struct v4l2_requestbuffers passed from userspace to
83 * &v4l2_ioctl_ops->vidioc_reqbufs handler in driver.
84 */
85int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req);
86
87/**
88 * vb2_create_bufs() - Wrapper for vb2_core_create_bufs() that also verifies
89 * the memory and type values.
90 *
91 * @q: pointer to &struct vb2_queue with videobuf2 queue.
92 * @create: creation parameters, passed from userspace to
93 * &v4l2_ioctl_ops->vidioc_create_bufs handler in driver
94 */
95int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create);
96
97/**
98 * vb2_prepare_buf() - Pass ownership of a buffer from userspace to the kernel
99 *
100 * @q: pointer to &struct vb2_queue with videobuf2 queue.
101 * @mdev: pointer to &struct media_device, may be NULL.
102 * @b: buffer structure passed from userspace to
103 * &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver
104 *
105 * Should be called from &v4l2_ioctl_ops->vidioc_prepare_buf ioctl handler
106 * of a driver.
107 *
108 * This function:
109 *
110 * #) verifies the passed buffer,
111 * #) calls &vb2_ops->buf_prepare callback in the driver (if provided),
112 * in which driver-specific buffer initialization can be performed.
113 * #) if @b->request_fd is non-zero and @mdev->ops->req_queue is set,
114 * then bind the prepared buffer to the request.
115 *
116 * The return values from this function are intended to be directly returned
117 * from &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver.
118 */
119int vb2_prepare_buf(struct vb2_queue *q, struct media_device *mdev,
120 struct v4l2_buffer *b);
121
122/**
123 * vb2_qbuf() - Queue a buffer from userspace
124 * @q: pointer to &struct vb2_queue with videobuf2 queue.
125 * @mdev: pointer to &struct media_device, may be NULL.
126 * @b: buffer structure passed from userspace to
127 * &v4l2_ioctl_ops->vidioc_qbuf handler in driver
128 *
129 * Should be called from &v4l2_ioctl_ops->vidioc_qbuf handler of a driver.
130 *
131 * This function:
132 *
133 * #) verifies the passed buffer;
134 * #) if @b->request_fd is non-zero and @mdev->ops->req_queue is set,
135 * then bind the buffer to the request.
136 * #) if necessary, calls &vb2_ops->buf_prepare callback in the driver
137 * (if provided), in which driver-specific buffer initialization can
138 * be performed;
139 * #) if streaming is on, queues the buffer in driver by the means of
140 * &vb2_ops->buf_queue callback for processing.
141 *
142 * The return values from this function are intended to be directly returned
143 * from &v4l2_ioctl_ops->vidioc_qbuf handler in driver.
144 */
145int vb2_qbuf(struct vb2_queue *q, struct media_device *mdev,
146 struct v4l2_buffer *b);
147
148/**
149 * vb2_expbuf() - Export a buffer as a file descriptor
150 * @q: pointer to &struct vb2_queue with videobuf2 queue.
151 * @eb: export buffer structure passed from userspace to
152 * &v4l2_ioctl_ops->vidioc_expbuf handler in driver
153 *
154 * The return values from this function are intended to be directly returned
155 * from &v4l2_ioctl_ops->vidioc_expbuf handler in driver.
156 */
157int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb);
158
159/**
160 * vb2_dqbuf() - Dequeue a buffer to the userspace
161 * @q: pointer to &struct vb2_queue with videobuf2 queue.
162 * @b: buffer structure passed from userspace to
163 * &v4l2_ioctl_ops->vidioc_dqbuf handler in driver
164 * @nonblocking: if true, this call will not sleep waiting for a buffer if no
165 * buffers ready for dequeuing are present. Normally the driver
166 * would be passing (&file->f_flags & %O_NONBLOCK) here
167 *
168 * Should be called from &v4l2_ioctl_ops->vidioc_dqbuf ioctl handler
169 * of a driver.
170 *
171 * This function:
172 *
173 * #) verifies the passed buffer;
174 * #) calls &vb2_ops->buf_finish callback in the driver (if provided), in which
175 * driver can perform any additional operations that may be required before
176 * returning the buffer to userspace, such as cache sync;
177 * #) the buffer struct members are filled with relevant information for
178 * the userspace.
179 *
180 * The return values from this function are intended to be directly returned
181 * from &v4l2_ioctl_ops->vidioc_dqbuf handler in driver.
182 */
183int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking);
184
185/**
186 * vb2_streamon - start streaming
187 * @q: pointer to &struct vb2_queue with videobuf2 queue.
188 * @type: type argument passed from userspace to vidioc_streamon handler,
189 * as defined by &enum v4l2_buf_type.
190 *
191 * Should be called from &v4l2_ioctl_ops->vidioc_streamon handler of a driver.
192 *
193 * This function:
194 *
195 * 1) verifies current state
196 * 2) passes any previously queued buffers to the driver and starts streaming
197 *
198 * The return values from this function are intended to be directly returned
199 * from &v4l2_ioctl_ops->vidioc_streamon handler in the driver.
200 */
201int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type);
202
203/**
204 * vb2_streamoff - stop streaming
205 * @q: pointer to &struct vb2_queue with videobuf2 queue.
206 * @type: type argument passed from userspace to vidioc_streamoff handler
207 *
208 * Should be called from vidioc_streamoff handler of a driver.
209 *
210 * This function:
211 *
212 * #) verifies current state,
213 * #) stop streaming and dequeues any queued buffers, including those previously
214 * passed to the driver (after waiting for the driver to finish).
215 *
216 * This call can be used for pausing playback.
217 * The return values from this function are intended to be directly returned
218 * from vidioc_streamoff handler in the driver
219 */
220int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type);
221
222/**
223 * vb2_queue_init() - initialize a videobuf2 queue
224 * @q: pointer to &struct vb2_queue with videobuf2 queue.
225 *
226 * The vb2_queue structure should be allocated by the driver. The driver is
227 * responsible of clearing it's content and setting initial values for some
228 * required entries before calling this function.
229 * q->ops, q->mem_ops, q->type and q->io_modes are mandatory. Please refer
230 * to the struct vb2_queue description in include/media/videobuf2-core.h
231 * for more information.
232 */
233int __must_check vb2_queue_init(struct vb2_queue *q);
234
235/**
236 * vb2_queue_init_name() - initialize a videobuf2 queue with a name
237 * @q: pointer to &struct vb2_queue with videobuf2 queue.
238 * @name: the queue name
239 *
240 * This function initializes the vb2_queue exactly like vb2_queue_init(),
241 * and additionally sets the queue name. The queue name is used for logging
242 * purpose, and should uniquely identify the queue within the context of the
243 * device it belongs to. This is useful to attribute kernel log messages to the
244 * right queue for m2m devices or other devices that handle multiple queues.
245 */
246int __must_check vb2_queue_init_name(struct vb2_queue *q, const char *name);
247
248/**
249 * vb2_queue_release() - stop streaming, release the queue and free memory
250 * @q: pointer to &struct vb2_queue with videobuf2 queue.
251 *
252 * This function stops streaming and performs necessary clean ups, including
253 * freeing video buffer memory. The driver is responsible for freeing
254 * the vb2_queue structure itself.
255 */
256void vb2_queue_release(struct vb2_queue *q);
257
258/**
259 * vb2_queue_change_type() - change the type of an inactive vb2_queue
260 * @q: pointer to &struct vb2_queue with videobuf2 queue.
261 * @type: the type to change to (V4L2_BUF_TYPE_VIDEO_*)
262 *
263 * This function changes the type of the vb2_queue. This is only possible
264 * if the queue is not busy (i.e. no buffers have been allocated).
265 *
266 * vb2_queue_change_type() can be used to support multiple buffer types using
267 * the same queue. The driver can implement v4l2_ioctl_ops.vidioc_reqbufs and
268 * v4l2_ioctl_ops.vidioc_create_bufs functions and call vb2_queue_change_type()
269 * before calling vb2_ioctl_reqbufs() or vb2_ioctl_create_bufs(), and thus
270 * "lock" the buffer type until the buffers have been released.
271 */
272int vb2_queue_change_type(struct vb2_queue *q, unsigned int type);
273
274/**
275 * vb2_poll() - implements poll userspace operation
276 * @q: pointer to &struct vb2_queue with videobuf2 queue.
277 * @file: file argument passed to the poll file operation handler
278 * @wait: wait argument passed to the poll file operation handler
279 *
280 * This function implements poll file operation handler for a driver.
281 * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will
282 * be informed that the file descriptor of a video device is available for
283 * reading.
284 * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor
285 * will be reported as available for writing.
286 *
287 * If the driver uses struct v4l2_fh, then vb2_poll() will also check for any
288 * pending events.
289 *
290 * The return values from this function are intended to be directly returned
291 * from poll handler in driver.
292 */
293__poll_t vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait);
294
295/*
296 * The following functions are not part of the vb2 core API, but are simple
297 * helper functions that you can use in your struct v4l2_file_operations,
298 * struct v4l2_ioctl_ops and struct vb2_ops. They will serialize if vb2_queue->lock
299 * or video_device->lock is set, and they will set and test the queue owner
300 * (vb2_queue->owner) to check if the calling filehandle is permitted to do the
301 * queuing operation.
302 */
303
304/**
305 * vb2_queue_is_busy() - check if the queue is busy
306 * @q: pointer to &struct vb2_queue with videobuf2 queue.
307 * @file: file through which the vb2 queue access is performed
308 *
309 * The queue is considered busy if it has an owner and the owner is not the
310 * @file.
311 *
312 * Queue ownership is acquired and checked by some of the v4l2_ioctl_ops helpers
313 * below. Drivers can also use this function directly when they need to
314 * open-code ioctl handlers, for instance to add additional checks between the
315 * queue ownership test and the call to the corresponding vb2 operation.
316 */
317static inline bool vb2_queue_is_busy(struct vb2_queue *q, struct file *file)
318{
319 return q->owner && q->owner != file->private_data;
320}
321
322/* struct v4l2_ioctl_ops helpers */
323
324int vb2_ioctl_reqbufs(struct file *file, void *priv,
325 struct v4l2_requestbuffers *p);
326int vb2_ioctl_create_bufs(struct file *file, void *priv,
327 struct v4l2_create_buffers *p);
328int vb2_ioctl_prepare_buf(struct file *file, void *priv,
329 struct v4l2_buffer *p);
330int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p);
331int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p);
332int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p);
333int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i);
334int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i);
335int vb2_ioctl_expbuf(struct file *file, void *priv,
336 struct v4l2_exportbuffer *p);
337int vb2_ioctl_remove_bufs(struct file *file, void *priv,
338 struct v4l2_remove_buffers *p);
339
340/* struct v4l2_file_operations helpers */
341
342int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma);
343int vb2_fop_release(struct file *file);
344int _vb2_fop_release(struct file *file, struct mutex *lock);
345ssize_t vb2_fop_write(struct file *file, const char __user *buf,
346 size_t count, loff_t *ppos);
347ssize_t vb2_fop_read(struct file *file, char __user *buf,
348 size_t count, loff_t *ppos);
349__poll_t vb2_fop_poll(struct file *file, poll_table *wait);
350#ifndef CONFIG_MMU
351unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr,
352 unsigned long len, unsigned long pgoff, unsigned long flags);
353#endif
354
355/**
356 * vb2_video_unregister_device - unregister the video device and release queue
357 *
358 * @vdev: pointer to &struct video_device
359 *
360 * If the driver uses vb2_fop_release()/_vb2_fop_release(), then it should use
361 * vb2_video_unregister_device() instead of video_unregister_device().
362 *
363 * This function will call video_unregister_device() and then release the
364 * vb2_queue if streaming is in progress. This will stop streaming and
365 * this will simplify the unbind sequence since after this call all subdevs
366 * will have stopped streaming as well.
367 */
368void vb2_video_unregister_device(struct video_device *vdev);
369
370/**
371 * vb2_ops_wait_prepare - helper function to lock a struct &vb2_queue
372 *
373 * @vq: pointer to &struct vb2_queue
374 *
375 * ..note:: only use if vq->lock is non-NULL.
376 */
377void vb2_ops_wait_prepare(struct vb2_queue *vq);
378
379/**
380 * vb2_ops_wait_finish - helper function to unlock a struct &vb2_queue
381 *
382 * @vq: pointer to &struct vb2_queue
383 *
384 * ..note:: only use if vq->lock is non-NULL.
385 */
386void vb2_ops_wait_finish(struct vb2_queue *vq);
387
388struct media_request;
389int vb2_request_validate(struct media_request *req);
390void vb2_request_queue(struct media_request *req);
391
392#endif /* _MEDIA_VIDEOBUF2_V4L2_H */
393

source code of linux/include/media/videobuf2-v4l2.h