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  * @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 */