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_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 */
78int vb2_find_timestamp(const struct vb2_queue *q, u64 timestamp,
79		       unsigned int start_idx);
80
81int 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 */
91int 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 */
101int 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 */
125int 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 */
151int 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 */
163int 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 */
189int 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 */
207int 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 */
226int 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 */
239int __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 */
252int __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 */
262void vb2_queue_release(struct vb2_queue *q);
263
264/**
265 * vb2_poll() - implements poll userspace operation
266 * @q:		pointer to &struct vb2_queue with videobuf2 queue.
267 * @file:	file argument passed to the poll file operation handler
268 * @wait:	wait argument passed to the poll file operation handler
269 *
270 * This function implements poll file operation handler for a driver.
271 * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will
272 * be informed that the file descriptor of a video device is available for
273 * reading.
274 * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor
275 * will be reported as available for writing.
276 *
277 * If the driver uses struct v4l2_fh, then vb2_poll() will also check for any
278 * pending events.
279 *
280 * The return values from this function are intended to be directly returned
281 * from poll handler in driver.
282 */
283__poll_t vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait);
284
285/*
286 * The following functions are not part of the vb2 core API, but are simple
287 * helper functions that you can use in your struct v4l2_file_operations,
288 * struct v4l2_ioctl_ops and struct vb2_ops. They will serialize if vb2_queue->lock
289 * or video_device->lock is set, and they will set and test vb2_queue->owner
290 * to check if the calling filehandle is permitted to do the queuing operation.
291 */
292
293/* struct v4l2_ioctl_ops helpers */
294
295int vb2_ioctl_reqbufs(struct file *file, void *priv,
296			  struct v4l2_requestbuffers *p);
297int vb2_ioctl_create_bufs(struct file *file, void *priv,
298			  struct v4l2_create_buffers *p);
299int vb2_ioctl_prepare_buf(struct file *file, void *priv,
300			  struct v4l2_buffer *p);
301int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p);
302int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p);
303int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p);
304int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i);
305int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i);
306int vb2_ioctl_expbuf(struct file *file, void *priv,
307	struct v4l2_exportbuffer *p);
308
309/* struct v4l2_file_operations helpers */
310
311int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma);
312int vb2_fop_release(struct file *file);
313int _vb2_fop_release(struct file *file, struct mutex *lock);
314ssize_t vb2_fop_write(struct file *file, const char __user *buf,
315		size_t count, loff_t *ppos);
316ssize_t vb2_fop_read(struct file *file, char __user *buf,
317		size_t count, loff_t *ppos);
318__poll_t vb2_fop_poll(struct file *file, poll_table *wait);
319#ifndef CONFIG_MMU
320unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr,
321		unsigned long len, unsigned long pgoff, unsigned long flags);
322#endif
323
324/**
325 * vb2_video_unregister_device - unregister the video device and release queue
326 *
327 * @vdev: pointer to &struct video_device
328 *
329 * If the driver uses vb2_fop_release()/_vb2_fop_release(), then it should use
330 * vb2_video_unregister_device() instead of video_unregister_device().
331 *
332 * This function will call video_unregister_device() and then release the
333 * vb2_queue if streaming is in progress. This will stop streaming and
334 * this will simplify the unbind sequence since after this call all subdevs
335 * will have stopped streaming as well.
336 */
337void vb2_video_unregister_device(struct video_device *vdev);
338
339/**
340 * vb2_ops_wait_prepare - helper function to lock a struct &vb2_queue
341 *
342 * @vq: pointer to &struct vb2_queue
343 *
344 * ..note:: only use if vq->lock is non-NULL.
345 */
346void vb2_ops_wait_prepare(struct vb2_queue *vq);
347
348/**
349 * vb2_ops_wait_finish - helper function to unlock a struct &vb2_queue
350 *
351 * @vq: pointer to &struct vb2_queue
352 *
353 * ..note:: only use if vq->lock is non-NULL.
354 */
355void vb2_ops_wait_finish(struct vb2_queue *vq);
356
357struct media_request;
358int vb2_request_validate(struct media_request *req);
359void vb2_request_queue(struct media_request *req);
360
361#endif /* _MEDIA_VIDEOBUF2_V4L2_H */
362