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