2 * videobuf2-v4l2.h - V4L2 driver helper framework
4 * Copyright (C) 2010 Samsung Electronics
6 * Author: Pawel Osciak <pawel@osciak.com>
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.
12 #ifndef _MEDIA_VIDEOBUF2_V4L2_H
13 #define _MEDIA_VIDEOBUF2_V4L2_H
15 #include <linux/videodev2.h>
16 #include <media/videobuf2-core.h>
18 #if VB2_MAX_FRAME != VIDEO_MAX_FRAME
19 #error VB2_MAX_FRAME != VIDEO_MAX_FRAME
22 #if VB2_MAX_PLANES != VIDEO_MAX_PLANES
23 #error VB2_MAX_PLANES != VIDEO_MAX_PLANES
29 * struct vb2_v4l2_buffer - video buffer information for v4l2.
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
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).
41 * Should contain enough information to be able to cover all the fields
42 * of &struct v4l2_buffer at ``videodev2.h``.
44 struct vb2_v4l2_buffer {
45 struct vb2_buffer vb2_buf;
49 struct v4l2_timecode timecode;
53 struct vb2_plane planes[VB2_MAX_PLANES];
56 /* VB2 V4L2 flags as set in vb2_queue.subsystem_flags */
57 #define VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF (1 << 0)
60 * to_vb2_v4l2_buffer() - cast struct vb2_buffer * to struct vb2_v4l2_buffer *
62 #define to_vb2_v4l2_buffer(vb) \
63 container_of(vb, struct vb2_v4l2_buffer, vb2_buf)
66 * vb2_find_timestamp() - Find buffer with given timestamp in the queue
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.
75 * Returns the buffer index of the buffer with the given @timestamp, or
76 * -1 if no buffer with @timestamp was found.
78 int vb2_find_timestamp(const struct vb2_queue *q, u64 timestamp,
79 unsigned int start_idx);
81 int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b);
84 * vb2_reqbufs() - Wrapper for vb2_core_reqbufs() that also verifies
85 * the memory and type values.
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.
91 int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req);
94 * vb2_create_bufs() - Wrapper for vb2_core_create_bufs() that also verifies
95 * the memory and type values.
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
101 int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create);
104 * vb2_prepare_buf() - Pass ownership of a buffer from userspace to the kernel
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
111 * Should be called from &v4l2_ioctl_ops->vidioc_prepare_buf ioctl handler
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.
122 * The return values from this function are intended to be directly returned
123 * from &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver.
125 int vb2_prepare_buf(struct vb2_queue *q, struct media_device *mdev,
126 struct v4l2_buffer *b);
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
135 * Should be called from &v4l2_ioctl_ops->vidioc_qbuf handler of a driver.
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
145 * #) if streaming is on, queues the buffer in driver by the means of
146 * &vb2_ops->buf_queue callback for processing.
148 * The return values from this function are intended to be directly returned
149 * from &v4l2_ioctl_ops->vidioc_qbuf handler in driver.
151 int vb2_qbuf(struct vb2_queue *q, struct media_device *mdev,
152 struct v4l2_buffer *b);
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
160 * The return values from this function are intended to be directly returned
161 * from &v4l2_ioctl_ops->vidioc_expbuf handler in driver.
163 int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb);
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
174 * Should be called from &v4l2_ioctl_ops->vidioc_dqbuf ioctl handler
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
186 * The return values from this function are intended to be directly returned
187 * from &v4l2_ioctl_ops->vidioc_dqbuf handler in driver.
189 int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking);
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.
197 * Should be called from &v4l2_ioctl_ops->vidioc_streamon handler of a driver.
201 * 1) verifies current state
202 * 2) passes any previously queued buffers to the driver and starts streaming
204 * The return values from this function are intended to be directly returned
205 * from &v4l2_ioctl_ops->vidioc_streamon handler in the driver.
207 int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type);
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
214 * Should be called from vidioc_streamoff handler of a driver.
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).
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
226 int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type);
229 * vb2_queue_init() - initialize a videobuf2 queue
230 * @q: pointer to &struct vb2_queue with videobuf2 queue.
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.
239 int __must_check vb2_queue_init(struct vb2_queue *q);
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
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.
252 int __must_check vb2_queue_init_name(struct vb2_queue *q, const char *name);
255 * vb2_queue_release() - stop streaming, release the queue and free memory
256 * @q: pointer to &struct vb2_queue with videobuf2 queue.
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.
262 void vb2_queue_release(struct vb2_queue *q);
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_*)
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).
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.
278 int vb2_queue_change_type(struct vb2_queue *q, unsigned int type);
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
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
290 * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor
291 * will be reported as available for writing.
293 * If the driver uses struct v4l2_fh, then vb2_poll() will also check for any
296 * The return values from this function are intended to be directly returned
297 * from poll handler in driver.
299 __poll_t vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait);
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.
309 /* struct v4l2_ioctl_ops helpers */
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);
325 /* struct v4l2_file_operations helpers */
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);
336 unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr,
337 unsigned long len, unsigned long pgoff, unsigned long flags);
341 * vb2_video_unregister_device - unregister the video device and release queue
343 * @vdev: pointer to &struct video_device
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().
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.
353 void vb2_video_unregister_device(struct video_device *vdev);
356 * vb2_ops_wait_prepare - helper function to lock a struct &vb2_queue
358 * @vq: pointer to &struct vb2_queue
360 * ..note:: only use if vq->lock is non-NULL.
362 void vb2_ops_wait_prepare(struct vb2_queue *vq);
365 * vb2_ops_wait_finish - helper function to unlock a struct &vb2_queue
367 * @vq: pointer to &struct vb2_queue
369 * ..note:: only use if vq->lock is non-NULL.
371 void vb2_ops_wait_finish(struct vb2_queue *vq);
373 struct media_request;
374 int vb2_request_validate(struct media_request *req);
375 void vb2_request_queue(struct media_request *req);
377 #endif /* _MEDIA_VIDEOBUF2_V4L2_H */