include/media/videobuf2-v4l2.h

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