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