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_timestamp() - Find buffer with given timestamp in the queue
67  *
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.
74  *
75  * Returns the buffer index of the buffer with the given @timestamp, or
76  * -1 if no buffer with @timestamp was found.
77  */
78 int vb2_find_timestamp(const struct vb2_queue *q, u64 timestamp,
79 		       unsigned int start_idx);
80 
81 int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b);
82 
83 /**
84  * vb2_reqbufs() - Wrapper for vb2_core_reqbufs() that also verifies
85  * the memory and type values.
86  *
87  * @q:		pointer to &struct vb2_queue with videobuf2 queue.
88  * @req:	&struct v4l2_requestbuffers passed from userspace to
89  *		&v4l2_ioctl_ops->vidioc_reqbufs handler in driver.
90  */
91 int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req);
92 
93 /**
94  * vb2_create_bufs() - Wrapper for vb2_core_create_bufs() that also verifies
95  * the memory and type values.
96  *
97  * @q:		pointer to &struct vb2_queue with videobuf2 queue.
98  * @create:	creation parameters, passed from userspace to
99  *		&v4l2_ioctl_ops->vidioc_create_bufs handler in driver
100  */
101 int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create);
102 
103 /**
104  * vb2_prepare_buf() - Pass ownership of a buffer from userspace to the kernel
105  *
106  * @q:		pointer to &struct vb2_queue with videobuf2 queue.
107  * @mdev:	pointer to &struct media_device, may be NULL.
108  * @b:		buffer structure passed from userspace to
109  *		&v4l2_ioctl_ops->vidioc_prepare_buf handler in driver
110  *
111  * Should be called from &v4l2_ioctl_ops->vidioc_prepare_buf ioctl handler
112  * of a driver.
113  *
114  * This function:
115  *
116  * #) verifies the passed buffer,
117  * #) calls &vb2_ops->buf_prepare callback in the driver (if provided),
118  *    in which driver-specific buffer initialization can be performed.
119  * #) if @b->request_fd is non-zero and @mdev->ops->req_queue is set,
120  *    then bind the prepared buffer to the request.
121  *
122  * The return values from this function are intended to be directly returned
123  * from &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver.
124  */
125 int vb2_prepare_buf(struct vb2_queue *q, struct media_device *mdev,
126 		    struct v4l2_buffer *b);
127 
128 /**
129  * vb2_qbuf() - Queue a buffer from userspace
130  * @q:		pointer to &struct vb2_queue with videobuf2 queue.
131  * @mdev:	pointer to &struct media_device, may be NULL.
132  * @b:		buffer structure passed from userspace to
133  *		&v4l2_ioctl_ops->vidioc_qbuf handler in driver
134  *
135  * Should be called from &v4l2_ioctl_ops->vidioc_qbuf handler of a driver.
136  *
137  * This function:
138  *
139  * #) verifies the passed buffer;
140  * #) if @b->request_fd is non-zero and @mdev->ops->req_queue is set,
141  *    then bind the buffer to the request.
142  * #) if necessary, calls &vb2_ops->buf_prepare callback in the driver
143  *    (if provided), in which driver-specific buffer initialization can
144  *    be performed;
145  * #) if streaming is on, queues the buffer in driver by the means of
146  *    &vb2_ops->buf_queue callback for processing.
147  *
148  * The return values from this function are intended to be directly returned
149  * from &v4l2_ioctl_ops->vidioc_qbuf handler in driver.
150  */
151 int vb2_qbuf(struct vb2_queue *q, struct media_device *mdev,
152 	     struct v4l2_buffer *b);
153 
154 /**
155  * vb2_expbuf() - Export a buffer as a file descriptor
156  * @q:		pointer to &struct vb2_queue with videobuf2 queue.
157  * @eb:		export buffer structure passed from userspace to
158  *		&v4l2_ioctl_ops->vidioc_expbuf handler in driver
159  *
160  * The return values from this function are intended to be directly returned
161  * from &v4l2_ioctl_ops->vidioc_expbuf handler in driver.
162  */
163 int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb);
164 
165 /**
166  * vb2_dqbuf() - Dequeue a buffer to the userspace
167  * @q:		pointer to &struct vb2_queue with videobuf2 queue.
168  * @b:		buffer structure passed from userspace to
169  *		&v4l2_ioctl_ops->vidioc_dqbuf handler in driver
170  * @nonblocking: if true, this call will not sleep waiting for a buffer if no
171  *		 buffers ready for dequeuing are present. Normally the driver
172  *		 would be passing (&file->f_flags & %O_NONBLOCK) here
173  *
174  * Should be called from &v4l2_ioctl_ops->vidioc_dqbuf ioctl handler
175  * of a driver.
176  *
177  * This function:
178  *
179  * #) verifies the passed buffer;
180  * #) calls &vb2_ops->buf_finish callback in the driver (if provided), in which
181  *    driver can perform any additional operations that may be required before
182  *    returning the buffer to userspace, such as cache sync;
183  * #) the buffer struct members are filled with relevant information for
184  *    the userspace.
185  *
186  * The return values from this function are intended to be directly returned
187  * from &v4l2_ioctl_ops->vidioc_dqbuf handler in driver.
188  */
189 int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking);
190 
191 /**
192  * vb2_streamon - start streaming
193  * @q:		pointer to &struct vb2_queue with videobuf2 queue.
194  * @type:	type argument passed from userspace to vidioc_streamon handler,
195  *		as defined by &enum v4l2_buf_type.
196  *
197  * Should be called from &v4l2_ioctl_ops->vidioc_streamon handler of a driver.
198  *
199  * This function:
200  *
201  * 1) verifies current state
202  * 2) passes any previously queued buffers to the driver and starts streaming
203  *
204  * The return values from this function are intended to be directly returned
205  * from &v4l2_ioctl_ops->vidioc_streamon handler in the driver.
206  */
207 int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type);
208 
209 /**
210  * vb2_streamoff - stop streaming
211  * @q:		pointer to &struct vb2_queue with videobuf2 queue.
212  * @type:	type argument passed from userspace to vidioc_streamoff handler
213  *
214  * Should be called from vidioc_streamoff handler of a driver.
215  *
216  * This function:
217  *
218  * #) verifies current state,
219  * #) stop streaming and dequeues any queued buffers, including those previously
220  *    passed to the driver (after waiting for the driver to finish).
221  *
222  * This call can be used for pausing playback.
223  * The return values from this function are intended to be directly returned
224  * from vidioc_streamoff handler in the driver
225  */
226 int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type);
227 
228 /**
229  * vb2_queue_init() - initialize a videobuf2 queue
230  * @q:		pointer to &struct vb2_queue with videobuf2 queue.
231  *
232  * The vb2_queue structure should be allocated by the driver. The driver is
233  * responsible of clearing it's content and setting initial values for some
234  * required entries before calling this function.
235  * q->ops, q->mem_ops, q->type and q->io_modes are mandatory. Please refer
236  * to the struct vb2_queue description in include/media/videobuf2-core.h
237  * for more information.
238  */
239 int __must_check vb2_queue_init(struct vb2_queue *q);
240 
241 /**
242  * vb2_queue_init_name() - initialize a videobuf2 queue with a name
243  * @q:		pointer to &struct vb2_queue with videobuf2 queue.
244  * @name:	the queue name
245  *
246  * This function initializes the vb2_queue exactly like vb2_queue_init(),
247  * and additionally sets the queue name. The queue name is used for logging
248  * purpose, and should uniquely identify the queue within the context of the
249  * device it belongs to. This is useful to attribute kernel log messages to the
250  * right queue for m2m devices or other devices that handle multiple queues.
251  */
252 int __must_check vb2_queue_init_name(struct vb2_queue *q, const char *name);
253 
254 /**
255  * vb2_queue_release() - stop streaming, release the queue and free memory
256  * @q:		pointer to &struct vb2_queue with videobuf2 queue.
257  *
258  * This function stops streaming and performs necessary clean ups, including
259  * freeing video buffer memory. The driver is responsible for freeing
260  * the vb2_queue structure itself.
261  */
262 void vb2_queue_release(struct vb2_queue *q);
263 
264 /**
265  * vb2_queue_change_type() - change the type of an inactive vb2_queue
266  * @q:		pointer to &struct vb2_queue with videobuf2 queue.
267  * @type:	the type to change to (V4L2_BUF_TYPE_VIDEO_*)
268  *
269  * This function changes the type of the vb2_queue. This is only possible
270  * if the queue is not busy (i.e. no buffers have been allocated).
271  *
272  * vb2_queue_change_type() can be used to support multiple buffer types using
273  * the same queue. The driver can implement v4l2_ioctl_ops.vidioc_reqbufs and
274  * v4l2_ioctl_ops.vidioc_create_bufs functions and call vb2_queue_change_type()
275  * before calling vb2_ioctl_reqbufs() or vb2_ioctl_create_bufs(), and thus
276  * "lock" the buffer type until the buffers have been released.
277  */
278 int vb2_queue_change_type(struct vb2_queue *q, unsigned int type);
279 
280 /**
281  * vb2_poll() - implements poll userspace operation
282  * @q:		pointer to &struct vb2_queue with videobuf2 queue.
283  * @file:	file argument passed to the poll file operation handler
284  * @wait:	wait argument passed to the poll file operation handler
285  *
286  * This function implements poll file operation handler for a driver.
287  * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will
288  * be informed that the file descriptor of a video device is available for
289  * reading.
290  * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor
291  * will be reported as available for writing.
292  *
293  * If the driver uses struct v4l2_fh, then vb2_poll() will also check for any
294  * pending events.
295  *
296  * The return values from this function are intended to be directly returned
297  * from poll handler in driver.
298  */
299 __poll_t vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait);
300 
301 /*
302  * The following functions are not part of the vb2 core API, but are simple
303  * helper functions that you can use in your struct v4l2_file_operations,
304  * struct v4l2_ioctl_ops and struct vb2_ops. They will serialize if vb2_queue->lock
305  * or video_device->lock is set, and they will set and test vb2_queue->owner
306  * to check if the calling filehandle is permitted to do the queuing operation.
307  */
308 
309 /* struct v4l2_ioctl_ops helpers */
310 
311 int vb2_ioctl_reqbufs(struct file *file, void *priv,
312 			  struct v4l2_requestbuffers *p);
313 int vb2_ioctl_create_bufs(struct file *file, void *priv,
314 			  struct v4l2_create_buffers *p);
315 int vb2_ioctl_prepare_buf(struct file *file, void *priv,
316 			  struct v4l2_buffer *p);
317 int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p);
318 int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p);
319 int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p);
320 int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i);
321 int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i);
322 int vb2_ioctl_expbuf(struct file *file, void *priv,
323 	struct v4l2_exportbuffer *p);
324 
325 /* struct v4l2_file_operations helpers */
326 
327 int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma);
328 int vb2_fop_release(struct file *file);
329 int _vb2_fop_release(struct file *file, struct mutex *lock);
330 ssize_t vb2_fop_write(struct file *file, const char __user *buf,
331 		size_t count, loff_t *ppos);
332 ssize_t vb2_fop_read(struct file *file, char __user *buf,
333 		size_t count, loff_t *ppos);
334 __poll_t vb2_fop_poll(struct file *file, poll_table *wait);
335 #ifndef CONFIG_MMU
336 unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr,
337 		unsigned long len, unsigned long pgoff, unsigned long flags);
338 #endif
339 
340 /**
341  * vb2_video_unregister_device - unregister the video device and release queue
342  *
343  * @vdev: pointer to &struct video_device
344  *
345  * If the driver uses vb2_fop_release()/_vb2_fop_release(), then it should use
346  * vb2_video_unregister_device() instead of video_unregister_device().
347  *
348  * This function will call video_unregister_device() and then release the
349  * vb2_queue if streaming is in progress. This will stop streaming and
350  * this will simplify the unbind sequence since after this call all subdevs
351  * will have stopped streaming as well.
352  */
353 void vb2_video_unregister_device(struct video_device *vdev);
354 
355 /**
356  * vb2_ops_wait_prepare - helper function to lock a struct &vb2_queue
357  *
358  * @vq: pointer to &struct vb2_queue
359  *
360  * ..note:: only use if vq->lock is non-NULL.
361  */
362 void vb2_ops_wait_prepare(struct vb2_queue *vq);
363 
364 /**
365  * vb2_ops_wait_finish - helper function to unlock a struct &vb2_queue
366  *
367  * @vq: pointer to &struct vb2_queue
368  *
369  * ..note:: only use if vq->lock is non-NULL.
370  */
371 void vb2_ops_wait_finish(struct vb2_queue *vq);
372 
373 struct media_request;
374 int vb2_request_validate(struct media_request *req);
375 void vb2_request_queue(struct media_request *req);
376 
377 #endif /* _MEDIA_VIDEOBUF2_V4L2_H */
378