aboutsummaryrefslogtreecommitdiffstats
path: root/include/media/videobuf2-v4l2.h
blob: e9ea84c654063be737eb2a4e9814d7b5a37d1093 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
/*
 * videobuf2-v4l2.h - V4L2 driver helper framework
 *
 * Copyright (C) 2010 Samsung Electronics
 *
 * Author: Pawel Osciak <pawel@osciak.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation.
 */
#ifndef _MEDIA_VIDEOBUF2_V4L2_H
#define _MEDIA_VIDEOBUF2_V4L2_H

#include <linux/videodev2.h>
#include <media/videobuf2-core.h>

#if VB2_MAX_FRAME != VIDEO_MAX_FRAME
#error VB2_MAX_FRAME != VIDEO_MAX_FRAME
#endif

#if VB2_MAX_PLANES != VIDEO_MAX_PLANES
#error VB2_MAX_PLANES != VIDEO_MAX_PLANES
#endif

/**
 * struct vb2_v4l2_buffer - video buffer information for v4l2
 *
 * @vb2_buf:	video buffer 2
 * @flags:	buffer informational flags
 * @field:	enum v4l2_field; field order of the image in the buffer
 * @timecode:	frame timecode
 * @sequence:	sequence count of this frame
 *
 * Should contain enough information to be able to cover all the fields
 * of struct v4l2_buffer at videodev2.h
 */
struct vb2_v4l2_buffer {
	struct vb2_buffer	vb2_buf;

	__u32			flags;
	__u32			field;
	struct v4l2_timecode	timecode;
	__u32			sequence;
};

/*
 * to_vb2_v4l2_buffer() - cast struct vb2_buffer * to struct vb2_v4l2_buffer *
 */
#define to_vb2_v4l2_buffer(vb) \
	container_of(vb, struct vb2_v4l2_buffer, vb2_buf)

int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b);
int vb2_ext_querybuf(struct vb2_queue *q, struct v4l2_ext_buffer *b);

/**
 * vb2_reqbufs() - Wrapper for vb2_core_reqbufs() that also verifies
 * the memory and type values.
 *
 * @q:		videobuf2 queue
 * @req:	struct passed from userspace to vidioc_reqbufs handler
 *		in driver
 */
int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req);

/**
 * vb2_create_bufs() - Wrapper for vb2_core_create_bufs() that also verifies
 * the memory and type values.
 *
 * @q:		videobuf2 queue
 * @create:	creation parameters, passed from userspace to vidioc_create_bufs
 *		handler in driver
 */
int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create);

/**
 * vb2_prepare_buf() - Pass ownership of a buffer from userspace to the kernel
 *
 * @q:		videobuf2 queue
 * @b:		buffer structure passed from userspace to vidioc_prepare_buf
 *		handler in driver
 *
 * Should be called from vidioc_prepare_buf ioctl handler of a driver.
 * This function:
 *
 * #) verifies the passed buffer,
 * #) calls buf_prepare callback in the driver (if provided), in which
 *    driver-specific buffer initialization can be performed.
 *
 * The return values from this function are intended to be directly returned
 * from vidioc_prepare_buf handler in driver.
 */
int vb2_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b);
int vb2_ext_prepare_buf(struct vb2_queue *q, struct v4l2_ext_buffer *b);

/**
 * vb2_qbuf() - Queue a buffer from userspace
 * @q:		videobuf2 queue
 * @b:		buffer structure passed from userspace to VIDIOC_QBUF() handler
 *		in driver
 *
 * Should be called from VIDIOC_QBUF() ioctl handler of a driver.
 *
 * This function:
 *
 * #) verifies the passed buffer,
 * #) if necessary, calls buf_prepare callback in the driver (if provided), in
 *    which driver-specific buffer initialization can be performed,
 * #) if streaming is on, queues the buffer in driver by the means of buf_queue
 *    callback for processing.
 *
 * The return values from this function are intended to be directly returned
 * from VIDIOC_QBUF() handler in driver.
 */
int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b);
int vb2_ext_qbuf(struct vb2_queue *q, struct v4l2_ext_buffer *b);

/**
 * vb2_expbuf() - Export a buffer as a file descriptor
 * @q:		videobuf2 queue
 * @eb:		export buffer structure passed from userspace to VIDIOC_EXPBUF()
 *		handler in driver
 *
 * The return values from this function are intended to be directly returned
 * from VIDIOC_EXPBUF() handler in driver.
 */
int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb);

/**
 * vb2_dqbuf() - Dequeue a buffer to the userspace
 * @q:		videobuf2 queue
 * @b:		buffer structure passed from userspace to VIDIOC_DQBUF() handler
 *		in driver
 * @nonblocking: if true, this call will not sleep waiting for a buffer if no
 *		 buffers ready for dequeuing are present. Normally the driver
 *		 would be passing (file->f_flags & O_NONBLOCK) here
 *
 * Should be called from VIDIOC_DQBUF() ioctl handler of a driver.
 *
 * This function:
 *
 * #) verifies the passed buffer,
 * #) calls buf_finish callback in the driver (if provided), in which
 *    driver can perform any additional operations that may be required before
 *    returning the buffer to userspace, such as cache sync,
 * #) the buffer struct members are filled with relevant information for
 *    the userspace.
 *
 * The return values from this function are intended to be directly returned
 * from VIDIOC_DQBUF() handler in driver.
 */
int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking);
int vb2_ext_dqbuf(struct vb2_queue *q, struct v4l2_ext_buffer *b, bool nonblocking);

/**
 * vb2_streamon - start streaming
 * @q:		videobuf2 queue
 * @type:	type argument passed from userspace to vidioc_streamon handler
 *
 * Should be called from vidioc_streamon handler of a driver.
 *
 * This function:
 *
 * 1) verifies current state
 * 2) passes any previously queued buffers to the driver and starts streaming
 *
 * The return values from this function are intended to be directly returned
 * from vidioc_streamon handler in the driver.
 */
int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type);

/**
 * vb2_streamoff - stop streaming
 * @q:		videobuf2 queue
 * @type:	type argument passed from userspace to vidioc_streamoff handler
 *
 * Should be called from vidioc_streamoff handler of a driver.
 *
 * This function:
 *
 * #) verifies current state,
 * #) stop streaming and dequeues any queued buffers, including those previously
 *    passed to the driver (after waiting for the driver to finish).
 *
 * This call can be used for pausing playback.
 * The return values from this function are intended to be directly returned
 * from vidioc_streamoff handler in the driver
 */
int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type);

/**
 * vb2_queue_init() - initialize a videobuf2 queue
 * @q:		videobuf2 queue; this structure should be allocated in driver
 *
 * The vb2_queue structure should be allocated by the driver. The driver is
 * responsible of clearing it's content and setting initial values for some
 * required entries before calling this function.
 * q->ops, q->mem_ops, q->type and q->io_modes are mandatory. Please refer
 * to the struct vb2_queue description in include/media/videobuf2-core.h
 * for more information.
 */
int __must_check vb2_queue_init(struct vb2_queue *q);

/**
 * vb2_queue_release() - stop streaming, release the queue and free memory
 * @q:		videobuf2 queue
 *
 * This function stops streaming and performs necessary clean ups, including
 * freeing video buffer memory. The driver is responsible for freeing
 * the vb2_queue structure itself.
 */
void vb2_queue_release(struct vb2_queue *q);

/**
 * vb2_poll() - implements poll userspace operation
 * @q:		videobuf2 queue
 * @file:	file argument passed to the poll file operation handler
 * @wait:	wait argument passed to the poll file operation handler
 *
 * This function implements poll file operation handler for a driver.
 * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will
 * be informed that the file descriptor of a video device is available for
 * reading.
 * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor
 * will be reported as available for writing.
 *
 * If the driver uses struct v4l2_fh, then vb2_poll() will also check for any
 * pending events.
 *
 * The return values from this function are intended to be directly returned
 * from poll handler in driver.
 */
unsigned int vb2_poll(struct vb2_queue *q, struct file *file,
		      poll_table *wait);

/*
 * The following functions are not part of the vb2 core API, but are simple
 * helper functions that you can use in your struct v4l2_file_operations,
 * struct v4l2_ioctl_ops and struct vb2_ops. They will serialize if vb2_queue->lock
 * or video_device->lock is set, and they will set and test vb2_queue->owner
 * to check if the calling filehandle is permitted to do the queuing operation.
 */

/* struct v4l2_ioctl_ops helpers */

int vb2_ioctl_reqbufs(struct file *file, void *priv,
			  struct v4l2_requestbuffers *p);
int vb2_ioctl_create_bufs(struct file *file, void *priv,
			  struct v4l2_create_buffers *p);
int vb2_ioctl_prepare_buf(struct file *file, void *priv,
			  struct v4l2_buffer *p);
int vb2_ioctl_ext_prepare_buf(struct file *file, void *priv,
			  struct v4l2_ext_buffer *p);
int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p);
int vb2_ioctl_ext_querybuf(struct file *file, void *priv, struct v4l2_ext_buffer *p);
int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p);
int vb2_ioctl_ext_qbuf(struct file *file, void *priv, struct v4l2_ext_buffer *p);
int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p);
int vb2_ioctl_ext_dqbuf(struct file *file, void *priv, struct v4l2_ext_buffer *p);
int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i);
int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i);
int vb2_ioctl_expbuf(struct file *file, void *priv,
	struct v4l2_exportbuffer *p);

/* struct v4l2_file_operations helpers */

int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma);
int vb2_fop_release(struct file *file);
int _vb2_fop_release(struct file *file, struct mutex *lock);
ssize_t vb2_fop_write(struct file *file, const char __user *buf,
		size_t count, loff_t *ppos);
ssize_t vb2_fop_read(struct file *file, char __user *buf,
		size_t count, loff_t *ppos);
unsigned int vb2_fop_poll(struct file *file, poll_table *wait);
#ifndef CONFIG_MMU
unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr,
		unsigned long len, unsigned long pgoff, unsigned long flags);
#endif

/**
 * vb2_ops_wait_prepare - helper function to lock a struct &vb2_queue
 *
 * @vq: pointer to struct vb2_queue
 *
 * ..note:: only use if vq->lock is non-NULL.
 */
void vb2_ops_wait_prepare(struct vb2_queue *vq);

/**
 * vb2_ops_wait_finish - helper function to unlock a struct &vb2_queue
 *
 * @vq: pointer to struct vb2_queue
 *
 * ..note:: only use if vq->lock is non-NULL.
 */
void vb2_ops_wait_finish(struct vb2_queue *vq);

#endif /* _MEDIA_VIDEOBUF2_V4L2_H */

Privacy Policy