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 | |
26 | struct 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 | */ |
44 | struct 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 | */ |
73 | struct vb2_buffer *vb2_find_buffer(struct vb2_queue *q, u64 timestamp); |
74 | |
75 | int 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 | */ |
85 | int 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 | */ |
95 | int 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 | */ |
119 | int 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 | */ |
145 | int 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 | */ |
157 | int 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 | */ |
183 | int 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 | */ |
201 | int 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 | */ |
220 | int 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 | */ |
233 | int __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 | */ |
246 | int __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 | */ |
256 | void 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 | */ |
272 | int 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 | */ |
317 | static 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 | |
324 | int vb2_ioctl_reqbufs(struct file *file, void *priv, |
325 | struct v4l2_requestbuffers *p); |
326 | int vb2_ioctl_create_bufs(struct file *file, void *priv, |
327 | struct v4l2_create_buffers *p); |
328 | int vb2_ioctl_prepare_buf(struct file *file, void *priv, |
329 | struct v4l2_buffer *p); |
330 | int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p); |
331 | int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p); |
332 | int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p); |
333 | int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i); |
334 | int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i); |
335 | int vb2_ioctl_expbuf(struct file *file, void *priv, |
336 | struct v4l2_exportbuffer *p); |
337 | |
338 | /* struct v4l2_file_operations helpers */ |
339 | |
340 | int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma); |
341 | int vb2_fop_release(struct file *file); |
342 | int _vb2_fop_release(struct file *file, struct mutex *lock); |
343 | ssize_t vb2_fop_write(struct file *file, const char __user *buf, |
344 | size_t count, loff_t *ppos); |
345 | ssize_t vb2_fop_read(struct file *file, char __user *buf, |
346 | size_t count, loff_t *ppos); |
347 | __poll_t vb2_fop_poll(struct file *file, poll_table *wait); |
348 | #ifndef CONFIG_MMU |
349 | unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr, |
350 | unsigned long len, unsigned long pgoff, unsigned long flags); |
351 | #endif |
352 | |
353 | /** |
354 | * vb2_video_unregister_device - unregister the video device and release queue |
355 | * |
356 | * @vdev: pointer to &struct video_device |
357 | * |
358 | * If the driver uses vb2_fop_release()/_vb2_fop_release(), then it should use |
359 | * vb2_video_unregister_device() instead of video_unregister_device(). |
360 | * |
361 | * This function will call video_unregister_device() and then release the |
362 | * vb2_queue if streaming is in progress. This will stop streaming and |
363 | * this will simplify the unbind sequence since after this call all subdevs |
364 | * will have stopped streaming as well. |
365 | */ |
366 | void vb2_video_unregister_device(struct video_device *vdev); |
367 | |
368 | /** |
369 | * vb2_ops_wait_prepare - helper function to lock a struct &vb2_queue |
370 | * |
371 | * @vq: pointer to &struct vb2_queue |
372 | * |
373 | * ..note:: only use if vq->lock is non-NULL. |
374 | */ |
375 | void vb2_ops_wait_prepare(struct vb2_queue *vq); |
376 | |
377 | /** |
378 | * vb2_ops_wait_finish - helper function to unlock a struct &vb2_queue |
379 | * |
380 | * @vq: pointer to &struct vb2_queue |
381 | * |
382 | * ..note:: only use if vq->lock is non-NULL. |
383 | */ |
384 | void vb2_ops_wait_finish(struct vb2_queue *vq); |
385 | |
386 | struct media_request; |
387 | int vb2_request_validate(struct media_request *req); |
388 | void vb2_request_queue(struct media_request *req); |
389 | |
390 | #endif /* _MEDIA_VIDEOBUF2_V4L2_H */ |
391 | |