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Linux/include/media/videobuf2-v4l2.h

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  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 /**
 27  * struct vb2_v4l2_buffer - video buffer information for v4l2.
 28  *
 29  * @vb2_buf:    embedded struct &vb2_buffer.
 30  * @flags:      buffer informational flags.
 31  * @field:      field order of the image in the buffer, as defined by
 32  *              &enum v4l2_field.
 33  * @timecode:   frame timecode.
 34  * @sequence:   sequence count of this frame.
 35  * @request_fd: the request_fd associated with this buffer
 36  * @planes:     plane information (userptr/fd, length, bytesused, data_offset).
 37  *
 38  * Should contain enough information to be able to cover all the fields
 39  * of &struct v4l2_buffer at ``videodev2.h``.
 40  */
 41 struct vb2_v4l2_buffer {
 42         struct vb2_buffer       vb2_buf;
 43 
 44         __u32                   flags;
 45         __u32                   field;
 46         struct v4l2_timecode    timecode;
 47         __u32                   sequence;
 48         __s32                   request_fd;
 49         struct vb2_plane        planes[VB2_MAX_PLANES];
 50 };
 51 
 52 /*
 53  * to_vb2_v4l2_buffer() - cast struct vb2_buffer * to struct vb2_v4l2_buffer *
 54  */
 55 #define to_vb2_v4l2_buffer(vb) \
 56         container_of(vb, struct vb2_v4l2_buffer, vb2_buf)
 57 
 58 /**
 59  * vb2_find_timestamp() - Find buffer with given timestamp in the queue
 60  *
 61  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
 62  * @timestamp:  the timestamp to find.
 63  * @start_idx:  the start index (usually 0) in the buffer array to start
 64  *              searching from. Note that there may be multiple buffers
 65  *              with the same timestamp value, so you can restart the search
 66  *              by setting @start_idx to the previously found index + 1.
 67  *
 68  * Returns the buffer index of the buffer with the given @timestamp, or
 69  * -1 if no buffer with @timestamp was found.
 70  */
 71 int vb2_find_timestamp(const struct vb2_queue *q, u64 timestamp,
 72                        unsigned int start_idx);
 73 
 74 int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b);
 75 
 76 /**
 77  * vb2_reqbufs() - Wrapper for vb2_core_reqbufs() that also verifies
 78  * the memory and type values.
 79  *
 80  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
 81  * @req:        &struct v4l2_requestbuffers passed from userspace to
 82  *              &v4l2_ioctl_ops->vidioc_reqbufs handler in driver.
 83  */
 84 int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req);
 85 
 86 /**
 87  * vb2_create_bufs() - Wrapper for vb2_core_create_bufs() that also verifies
 88  * the memory and type values.
 89  *
 90  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
 91  * @create:     creation parameters, passed from userspace to
 92  *              &v4l2_ioctl_ops->vidioc_create_bufs handler in driver
 93  */
 94 int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create);
 95 
 96 /**
 97  * vb2_prepare_buf() - Pass ownership of a buffer from userspace to the kernel
 98  *
 99  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
100  * @mdev:       pointer to &struct media_device, may be NULL.
101  * @b:          buffer structure passed from userspace to
102  *              &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver
103  *
104  * Should be called from &v4l2_ioctl_ops->vidioc_prepare_buf ioctl handler
105  * of a driver.
106  *
107  * This function:
108  *
109  * #) verifies the passed buffer,
110  * #) calls &vb2_ops->buf_prepare callback in the driver (if provided),
111  *    in which driver-specific buffer initialization can be performed.
112  * #) if @b->request_fd is non-zero and @mdev->ops->req_queue is set,
113  *    then bind the prepared buffer to the request.
114  *
115  * The return values from this function are intended to be directly returned
116  * from &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver.
117  */
118 int vb2_prepare_buf(struct vb2_queue *q, struct media_device *mdev,
119                     struct v4l2_buffer *b);
120 
121 /**
122  * vb2_qbuf() - Queue a buffer from userspace
123  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
124  * @mdev:       pointer to &struct media_device, may be NULL.
125  * @b:          buffer structure passed from userspace to
126  *              &v4l2_ioctl_ops->vidioc_qbuf handler in driver
127  *
128  * Should be called from &v4l2_ioctl_ops->vidioc_qbuf handler of a driver.
129  *
130  * This function:
131  *
132  * #) verifies the passed buffer;
133  * #) if @b->request_fd is non-zero and @mdev->ops->req_queue is set,
134  *    then bind the buffer to the request.
135  * #) if necessary, calls &vb2_ops->buf_prepare callback in the driver
136  *    (if provided), in which driver-specific buffer initialization can
137  *    be performed;
138  * #) if streaming is on, queues the buffer in driver by the means of
139  *    &vb2_ops->buf_queue callback for processing.
140  *
141  * The return values from this function are intended to be directly returned
142  * from &v4l2_ioctl_ops->vidioc_qbuf handler in driver.
143  */
144 int vb2_qbuf(struct vb2_queue *q, struct media_device *mdev,
145              struct v4l2_buffer *b);
146 
147 /**
148  * vb2_expbuf() - Export a buffer as a file descriptor
149  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
150  * @eb:         export buffer structure passed from userspace to
151  *              &v4l2_ioctl_ops->vidioc_expbuf handler in driver
152  *
153  * The return values from this function are intended to be directly returned
154  * from &v4l2_ioctl_ops->vidioc_expbuf handler in driver.
155  */
156 int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb);
157 
158 /**
159  * vb2_dqbuf() - Dequeue a buffer to the userspace
160  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
161  * @b:          buffer structure passed from userspace to
162  *              &v4l2_ioctl_ops->vidioc_dqbuf handler in driver
163  * @nonblocking: if true, this call will not sleep waiting for a buffer if no
164  *               buffers ready for dequeuing are present. Normally the driver
165  *               would be passing (&file->f_flags & %O_NONBLOCK) here
166  *
167  * Should be called from &v4l2_ioctl_ops->vidioc_dqbuf ioctl handler
168  * of a driver.
169  *
170  * This function:
171  *
172  * #) verifies the passed buffer;
173  * #) calls &vb2_ops->buf_finish callback in the driver (if provided), in which
174  *    driver can perform any additional operations that may be required before
175  *    returning the buffer to userspace, such as cache sync;
176  * #) the buffer struct members are filled with relevant information for
177  *    the userspace.
178  *
179  * The return values from this function are intended to be directly returned
180  * from &v4l2_ioctl_ops->vidioc_dqbuf handler in driver.
181  */
182 int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking);
183 
184 /**
185  * vb2_streamon - start streaming
186  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
187  * @type:       type argument passed from userspace to vidioc_streamon handler,
188  *              as defined by &enum v4l2_buf_type.
189  *
190  * Should be called from &v4l2_ioctl_ops->vidioc_streamon handler of a driver.
191  *
192  * This function:
193  *
194  * 1) verifies current state
195  * 2) passes any previously queued buffers to the driver and starts streaming
196  *
197  * The return values from this function are intended to be directly returned
198  * from &v4l2_ioctl_ops->vidioc_streamon handler in the driver.
199  */
200 int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type);
201 
202 /**
203  * vb2_streamoff - stop streaming
204  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
205  * @type:       type argument passed from userspace to vidioc_streamoff handler
206  *
207  * Should be called from vidioc_streamoff handler of a driver.
208  *
209  * This function:
210  *
211  * #) verifies current state,
212  * #) stop streaming and dequeues any queued buffers, including those previously
213  *    passed to the driver (after waiting for the driver to finish).
214  *
215  * This call can be used for pausing playback.
216  * The return values from this function are intended to be directly returned
217  * from vidioc_streamoff handler in the driver
218  */
219 int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type);
220 
221 /**
222  * vb2_queue_init() - initialize a videobuf2 queue
223  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
224  *
225  * The vb2_queue structure should be allocated by the driver. The driver is
226  * responsible of clearing it's content and setting initial values for some
227  * required entries before calling this function.
228  * q->ops, q->mem_ops, q->type and q->io_modes are mandatory. Please refer
229  * to the struct vb2_queue description in include/media/videobuf2-core.h
230  * for more information.
231  */
232 int __must_check vb2_queue_init(struct vb2_queue *q);
233 
234 /**
235  * vb2_queue_release() - stop streaming, release the queue and free memory
236  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
237  *
238  * This function stops streaming and performs necessary clean ups, including
239  * freeing video buffer memory. The driver is responsible for freeing
240  * the vb2_queue structure itself.
241  */
242 void vb2_queue_release(struct vb2_queue *q);
243 
244 /**
245  * vb2_poll() - implements poll userspace operation
246  * @q:          pointer to &struct vb2_queue with videobuf2 queue.
247  * @file:       file argument passed to the poll file operation handler
248  * @wait:       wait argument passed to the poll file operation handler
249  *
250  * This function implements poll file operation handler for a driver.
251  * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will
252  * be informed that the file descriptor of a video device is available for
253  * reading.
254  * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor
255  * will be reported as available for writing.
256  *
257  * If the driver uses struct v4l2_fh, then vb2_poll() will also check for any
258  * pending events.
259  *
260  * The return values from this function are intended to be directly returned
261  * from poll handler in driver.
262  */
263 __poll_t vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait);
264 
265 /*
266  * The following functions are not part of the vb2 core API, but are simple
267  * helper functions that you can use in your struct v4l2_file_operations,
268  * struct v4l2_ioctl_ops and struct vb2_ops. They will serialize if vb2_queue->lock
269  * or video_device->lock is set, and they will set and test vb2_queue->owner
270  * to check if the calling filehandle is permitted to do the queuing operation.
271  */
272 
273 /* struct v4l2_ioctl_ops helpers */
274 
275 int vb2_ioctl_reqbufs(struct file *file, void *priv,
276                           struct v4l2_requestbuffers *p);
277 int vb2_ioctl_create_bufs(struct file *file, void *priv,
278                           struct v4l2_create_buffers *p);
279 int vb2_ioctl_prepare_buf(struct file *file, void *priv,
280                           struct v4l2_buffer *p);
281 int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p);
282 int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p);
283 int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p);
284 int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i);
285 int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i);
286 int vb2_ioctl_expbuf(struct file *file, void *priv,
287         struct v4l2_exportbuffer *p);
288 
289 /* struct v4l2_file_operations helpers */
290 
291 int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma);
292 int vb2_fop_release(struct file *file);
293 int _vb2_fop_release(struct file *file, struct mutex *lock);
294 ssize_t vb2_fop_write(struct file *file, const char __user *buf,
295                 size_t count, loff_t *ppos);
296 ssize_t vb2_fop_read(struct file *file, char __user *buf,
297                 size_t count, loff_t *ppos);
298 __poll_t vb2_fop_poll(struct file *file, poll_table *wait);
299 #ifndef CONFIG_MMU
300 unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr,
301                 unsigned long len, unsigned long pgoff, unsigned long flags);
302 #endif
303 
304 /**
305  * vb2_ops_wait_prepare - helper function to lock a struct &vb2_queue
306  *
307  * @vq: pointer to &struct vb2_queue
308  *
309  * ..note:: only use if vq->lock is non-NULL.
310  */
311 void vb2_ops_wait_prepare(struct vb2_queue *vq);
312 
313 /**
314  * vb2_ops_wait_finish - helper function to unlock a struct &vb2_queue
315  *
316  * @vq: pointer to &struct vb2_queue
317  *
318  * ..note:: only use if vq->lock is non-NULL.
319  */
320 void vb2_ops_wait_finish(struct vb2_queue *vq);
321 
322 struct media_request;
323 int vb2_request_validate(struct media_request *req);
324 void vb2_request_queue(struct media_request *req);
325 
326 #endif /* _MEDIA_VIDEOBUF2_V4L2_H */
327 

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