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 struct video_device; 27 28 /** 29 * struct vb2_v4l2_buffer - video buffer information for v4l2. 30 * 31 * @vb2_buf: embedded struct &vb2_buffer. 32 * @flags: buffer informational flags. 33 * @field: field order of the image in the buffer, as defined by 34 * &enum v4l2_field. 35 * @timecode: frame timecode. 36 * @sequence: sequence count of this frame. 37 * @request_fd: the request_fd associated with this buffer 38 * @is_held: if true, then this capture buffer was held 39 * @planes: plane information (userptr/fd, length, bytesused, data_offset). 40 * 41 * Should contain enough information to be able to cover all the fields 42 * of &struct v4l2_buffer at ``videodev2.h``. 43 */ 44 struct vb2_v4l2_buffer { 45 struct vb2_buffer vb2_buf; 46 47 __u32 flags; 48 __u32 field; 49 struct v4l2_timecode timecode; 50 __u32 sequence; 51 __s32 request_fd; 52 bool is_held; 53 struct vb2_plane planes[VB2_MAX_PLANES]; 54 }; 55 56 /* VB2 V4L2 flags as set in vb2_queue.subsystem_flags */ 57 #define VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF (1 << 0) 58 59 /* 60 * to_vb2_v4l2_buffer() - cast struct vb2_buffer * to struct vb2_v4l2_buffer * 61 */ 62 #define to_vb2_v4l2_buffer(vb) \ 63 container_of(vb, struct vb2_v4l2_buffer, vb2_buf) 64 65 /** 66 * vb2_find_timestamp() - Find buffer with given timestamp in the queue 67 * 68 * @q: pointer to &struct vb2_queue with videobuf2 queue. 69 * @timestamp: the timestamp to find. 70 * @start_idx: the start index (usually 0) in the buffer array to start 71 * searching from. Note that there may be multiple buffers 72 * with the same timestamp value, so you can restart the search 73 * by setting @start_idx to the previously found index + 1. 74 * 75 * Returns the buffer index of the buffer with the given @timestamp, or 76 * -1 if no buffer with @timestamp was found. 77 */ 78 int vb2_find_timestamp(const struct vb2_queue *q, u64 timestamp, 79 unsigned int start_idx); 80 81 int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b); 82 83 /** 84 * vb2_reqbufs() - Wrapper for vb2_core_reqbufs() that also verifies 85 * the memory and type values. 86 * 87 * @q: pointer to &struct vb2_queue with videobuf2 queue. 88 * @req: &struct v4l2_requestbuffers passed from userspace to 89 * &v4l2_ioctl_ops->vidioc_reqbufs handler in driver. 90 */ 91 int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req); 92 93 /** 94 * vb2_create_bufs() - Wrapper for vb2_core_create_bufs() that also verifies 95 * the memory and type values. 96 * 97 * @q: pointer to &struct vb2_queue with videobuf2 queue. 98 * @create: creation parameters, passed from userspace to 99 * &v4l2_ioctl_ops->vidioc_create_bufs handler in driver 100 */ 101 int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create); 102 103 /** 104 * vb2_prepare_buf() - Pass ownership of a buffer from userspace to the kernel 105 * 106 * @q: pointer to &struct vb2_queue with videobuf2 queue. 107 * @mdev: pointer to &struct media_device, may be NULL. 108 * @b: buffer structure passed from userspace to 109 * &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver 110 * 111 * Should be called from &v4l2_ioctl_ops->vidioc_prepare_buf ioctl handler 112 * of a driver. 113 * 114 * This function: 115 * 116 * #) verifies the passed buffer, 117 * #) calls &vb2_ops->buf_prepare callback in the driver (if provided), 118 * in which driver-specific buffer initialization can be performed. 119 * #) if @b->request_fd is non-zero and @mdev->ops->req_queue is set, 120 * then bind the prepared buffer to the request. 121 * 122 * The return values from this function are intended to be directly returned 123 * from &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver. 124 */ 125 int vb2_prepare_buf(struct vb2_queue *q, struct media_device *mdev, 126 struct v4l2_buffer *b); 127 128 /** 129 * vb2_qbuf() - Queue a buffer from userspace 130 * @q: pointer to &struct vb2_queue with videobuf2 queue. 131 * @mdev: pointer to &struct media_device, may be NULL. 132 * @b: buffer structure passed from userspace to 133 * &v4l2_ioctl_ops->vidioc_qbuf handler in driver 134 * 135 * Should be called from &v4l2_ioctl_ops->vidioc_qbuf handler of a driver. 136 * 137 * This function: 138 * 139 * #) verifies the passed buffer; 140 * #) if @b->request_fd is non-zero and @mdev->ops->req_queue is set, 141 * then bind the buffer to the request. 142 * #) if necessary, calls &vb2_ops->buf_prepare callback in the driver 143 * (if provided), in which driver-specific buffer initialization can 144 * be performed; 145 * #) if streaming is on, queues the buffer in driver by the means of 146 * &vb2_ops->buf_queue callback for processing. 147 * 148 * The return values from this function are intended to be directly returned 149 * from &v4l2_ioctl_ops->vidioc_qbuf handler in driver. 150 */ 151 int vb2_qbuf(struct vb2_queue *q, struct media_device *mdev, 152 struct v4l2_buffer *b); 153 154 /** 155 * vb2_expbuf() - Export a buffer as a file descriptor 156 * @q: pointer to &struct vb2_queue with videobuf2 queue. 157 * @eb: export buffer structure passed from userspace to 158 * &v4l2_ioctl_ops->vidioc_expbuf handler in driver 159 * 160 * The return values from this function are intended to be directly returned 161 * from &v4l2_ioctl_ops->vidioc_expbuf handler in driver. 162 */ 163 int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb); 164 165 /** 166 * vb2_dqbuf() - Dequeue a buffer to the userspace 167 * @q: pointer to &struct vb2_queue with videobuf2 queue. 168 * @b: buffer structure passed from userspace to 169 * &v4l2_ioctl_ops->vidioc_dqbuf handler in driver 170 * @nonblocking: if true, this call will not sleep waiting for a buffer if no 171 * buffers ready for dequeuing are present. Normally the driver 172 * would be passing (&file->f_flags & %O_NONBLOCK) here 173 * 174 * Should be called from &v4l2_ioctl_ops->vidioc_dqbuf ioctl handler 175 * of a driver. 176 * 177 * This function: 178 * 179 * #) verifies the passed buffer; 180 * #) calls &vb2_ops->buf_finish callback in the driver (if provided), in which 181 * driver can perform any additional operations that may be required before 182 * returning the buffer to userspace, such as cache sync; 183 * #) the buffer struct members are filled with relevant information for 184 * the userspace. 185 * 186 * The return values from this function are intended to be directly returned 187 * from &v4l2_ioctl_ops->vidioc_dqbuf handler in driver. 188 */ 189 int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking); 190 191 /** 192 * vb2_streamon - start streaming 193 * @q: pointer to &struct vb2_queue with videobuf2 queue. 194 * @type: type argument passed from userspace to vidioc_streamon handler, 195 * as defined by &enum v4l2_buf_type. 196 * 197 * Should be called from &v4l2_ioctl_ops->vidioc_streamon handler of a driver. 198 * 199 * This function: 200 * 201 * 1) verifies current state 202 * 2) passes any previously queued buffers to the driver and starts streaming 203 * 204 * The return values from this function are intended to be directly returned 205 * from &v4l2_ioctl_ops->vidioc_streamon handler in the driver. 206 */ 207 int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type); 208 209 /** 210 * vb2_streamoff - stop streaming 211 * @q: pointer to &struct vb2_queue with videobuf2 queue. 212 * @type: type argument passed from userspace to vidioc_streamoff handler 213 * 214 * Should be called from vidioc_streamoff handler of a driver. 215 * 216 * This function: 217 * 218 * #) verifies current state, 219 * #) stop streaming and dequeues any queued buffers, including those previously 220 * passed to the driver (after waiting for the driver to finish). 221 * 222 * This call can be used for pausing playback. 223 * The return values from this function are intended to be directly returned 224 * from vidioc_streamoff handler in the driver 225 */ 226 int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type); 227 228 /** 229 * vb2_queue_init() - initialize a videobuf2 queue 230 * @q: pointer to &struct vb2_queue with videobuf2 queue. 231 * 232 * The vb2_queue structure should be allocated by the driver. The driver is 233 * responsible of clearing it's content and setting initial values for some 234 * required entries before calling this function. 235 * q->ops, q->mem_ops, q->type and q->io_modes are mandatory. Please refer 236 * to the struct vb2_queue description in include/media/videobuf2-core.h 237 * for more information. 238 */ 239 int __must_check vb2_queue_init(struct vb2_queue *q); 240 241 /** 242 * vb2_queue_init_name() - initialize a videobuf2 queue with a name 243 * @q: pointer to &struct vb2_queue with videobuf2 queue. 244 * @name: the queue name 245 * 246 * This function initializes the vb2_queue exactly like vb2_queue_init(), 247 * and additionally sets the queue name. The queue name is used for logging 248 * purpose, and should uniquely identify the queue within the context of the 249 * device it belongs to. This is useful to attribute kernel log messages to the 250 * right queue for m2m devices or other devices that handle multiple queues. 251 */ 252 int __must_check vb2_queue_init_name(struct vb2_queue *q, const char *name); 253 254 /** 255 * vb2_queue_release() - stop streaming, release the queue and free memory 256 * @q: pointer to &struct vb2_queue with videobuf2 queue. 257 * 258 * This function stops streaming and performs necessary clean ups, including 259 * freeing video buffer memory. The driver is responsible for freeing 260 * the vb2_queue structure itself. 261 */ 262 void vb2_queue_release(struct vb2_queue *q); 263 264 /** 265 * vb2_queue_change_type() - change the type of an inactive vb2_queue 266 * @q: pointer to &struct vb2_queue with videobuf2 queue. 267 * @type: the type to change to (V4L2_BUF_TYPE_VIDEO_*) 268 * 269 * This function changes the type of the vb2_queue. This is only possible 270 * if the queue is not busy (i.e. no buffers have been allocated). 271 * 272 * vb2_queue_change_type() can be used to support multiple buffer types using 273 * the same queue. The driver can implement v4l2_ioctl_ops.vidioc_reqbufs and 274 * v4l2_ioctl_ops.vidioc_create_bufs functions and call vb2_queue_change_type() 275 * before calling vb2_ioctl_reqbufs() or vb2_ioctl_create_bufs(), and thus 276 * "lock" the buffer type until the buffers have been released. 277 */ 278 int vb2_queue_change_type(struct vb2_queue *q, unsigned int type); 279 280 /** 281 * vb2_poll() - implements poll userspace operation 282 * @q: pointer to &struct vb2_queue with videobuf2 queue. 283 * @file: file argument passed to the poll file operation handler 284 * @wait: wait argument passed to the poll file operation handler 285 * 286 * This function implements poll file operation handler for a driver. 287 * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will 288 * be informed that the file descriptor of a video device is available for 289 * reading. 290 * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor 291 * will be reported as available for writing. 292 * 293 * If the driver uses struct v4l2_fh, then vb2_poll() will also check for any 294 * pending events. 295 * 296 * The return values from this function are intended to be directly returned 297 * from poll handler in driver. 298 */ 299 __poll_t vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait); 300 301 /* 302 * The following functions are not part of the vb2 core API, but are simple 303 * helper functions that you can use in your struct v4l2_file_operations, 304 * struct v4l2_ioctl_ops and struct vb2_ops. They will serialize if vb2_queue->lock 305 * or video_device->lock is set, and they will set and test vb2_queue->owner 306 * to check if the calling filehandle is permitted to do the queuing operation. 307 */ 308 309 /* struct v4l2_ioctl_ops helpers */ 310 311 int vb2_ioctl_reqbufs(struct file *file, void *priv, 312 struct v4l2_requestbuffers *p); 313 int vb2_ioctl_create_bufs(struct file *file, void *priv, 314 struct v4l2_create_buffers *p); 315 int vb2_ioctl_prepare_buf(struct file *file, void *priv, 316 struct v4l2_buffer *p); 317 int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p); 318 int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p); 319 int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p); 320 int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i); 321 int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i); 322 int vb2_ioctl_expbuf(struct file *file, void *priv, 323 struct v4l2_exportbuffer *p); 324 325 /* struct v4l2_file_operations helpers */ 326 327 int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma); 328 int vb2_fop_release(struct file *file); 329 int _vb2_fop_release(struct file *file, struct mutex *lock); 330 ssize_t vb2_fop_write(struct file *file, const char __user *buf, 331 size_t count, loff_t *ppos); 332 ssize_t vb2_fop_read(struct file *file, char __user *buf, 333 size_t count, loff_t *ppos); 334 __poll_t vb2_fop_poll(struct file *file, poll_table *wait); 335 #ifndef CONFIG_MMU 336 unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr, 337 unsigned long len, unsigned long pgoff, unsigned long flags); 338 #endif 339 340 /** 341 * vb2_video_unregister_device - unregister the video device and release queue 342 * 343 * @vdev: pointer to &struct video_device 344 * 345 * If the driver uses vb2_fop_release()/_vb2_fop_release(), then it should use 346 * vb2_video_unregister_device() instead of video_unregister_device(). 347 * 348 * This function will call video_unregister_device() and then release the 349 * vb2_queue if streaming is in progress. This will stop streaming and 350 * this will simplify the unbind sequence since after this call all subdevs 351 * will have stopped streaming as well. 352 */ 353 void vb2_video_unregister_device(struct video_device *vdev); 354 355 /** 356 * vb2_ops_wait_prepare - helper function to lock a struct &vb2_queue 357 * 358 * @vq: pointer to &struct vb2_queue 359 * 360 * ..note:: only use if vq->lock is non-NULL. 361 */ 362 void vb2_ops_wait_prepare(struct vb2_queue *vq); 363 364 /** 365 * vb2_ops_wait_finish - helper function to unlock a struct &vb2_queue 366 * 367 * @vq: pointer to &struct vb2_queue 368 * 369 * ..note:: only use if vq->lock is non-NULL. 370 */ 371 void vb2_ops_wait_finish(struct vb2_queue *vq); 372 373 struct media_request; 374 int vb2_request_validate(struct media_request *req); 375 void vb2_request_queue(struct media_request *req); 376 377 #endif /* _MEDIA_VIDEOBUF2_V4L2_H */ 378