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