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 <linux/android_kabi.h> 17 #include <media/videobuf2-core.h> 18 19 #if VB2_MAX_FRAME != VIDEO_MAX_FRAME 20 #error VB2_MAX_FRAME != VIDEO_MAX_FRAME 21 #endif 22 23 #if VB2_MAX_PLANES != VIDEO_MAX_PLANES 24 #error VB2_MAX_PLANES != VIDEO_MAX_PLANES 25 #endif 26 27 struct video_device; 28 29 /** 30 * struct vb2_v4l2_buffer - video buffer information for v4l2. 31 * 32 * @vb2_buf: embedded struct &vb2_buffer. 33 * @flags: buffer informational flags. 34 * @field: field order of the image in the buffer, as defined by 35 * &enum v4l2_field. 36 * @timecode: frame timecode. 37 * @sequence: sequence count of this frame. 38 * @request_fd: the request_fd associated with this buffer 39 * @is_held: if true, then this capture buffer was held 40 * @planes: plane information (userptr/fd, length, bytesused, data_offset). 41 * 42 * Should contain enough information to be able to cover all the fields 43 * of &struct v4l2_buffer at ``videodev2.h``. 44 */ 45 struct vb2_v4l2_buffer { 46 struct vb2_buffer vb2_buf; 47 48 __u32 flags; 49 __u32 field; 50 struct v4l2_timecode timecode; 51 __u32 sequence; 52 __s32 request_fd; 53 bool is_held; 54 struct vb2_plane planes[VB2_MAX_PLANES]; 55 56 ANDROID_KABI_RESERVE(1); 57 }; 58 59 /* VB2 V4L2 flags as set in vb2_queue.subsystem_flags */ 60 #define VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF (1 << 0) 61 62 /* 63 * to_vb2_v4l2_buffer() - cast struct vb2_buffer * to struct vb2_v4l2_buffer * 64 */ 65 #define to_vb2_v4l2_buffer(vb) \ 66 container_of(vb, struct vb2_v4l2_buffer, vb2_buf) 67 68 /** 69 * vb2_find_timestamp() - Find buffer with given timestamp in the queue 70 * 71 * @q: pointer to &struct vb2_queue with videobuf2 queue. 72 * @timestamp: the timestamp to find. 73 * @start_idx: the start index (usually 0) in the buffer array to start 74 * searching from. Note that there may be multiple buffers 75 * with the same timestamp value, so you can restart the search 76 * by setting @start_idx to the previously found index + 1. 77 * 78 * Returns the buffer index of the buffer with the given @timestamp, or 79 * -1 if no buffer with @timestamp was found. 80 */ 81 int vb2_find_timestamp(const struct vb2_queue *q, u64 timestamp, 82 unsigned int start_idx); 83 84 int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b); 85 86 /** 87 * vb2_reqbufs() - Wrapper for vb2_core_reqbufs() that also verifies 88 * the memory and type values. 89 * 90 * @q: pointer to &struct vb2_queue with videobuf2 queue. 91 * @req: &struct v4l2_requestbuffers passed from userspace to 92 * &v4l2_ioctl_ops->vidioc_reqbufs handler in driver. 93 */ 94 int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req); 95 96 /** 97 * vb2_create_bufs() - Wrapper for vb2_core_create_bufs() that also verifies 98 * the memory and type values. 99 * 100 * @q: pointer to &struct vb2_queue with videobuf2 queue. 101 * @create: creation parameters, passed from userspace to 102 * &v4l2_ioctl_ops->vidioc_create_bufs handler in driver 103 */ 104 int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create); 105 106 /** 107 * vb2_prepare_buf() - Pass ownership of a buffer from userspace to the kernel 108 * 109 * @q: pointer to &struct vb2_queue with videobuf2 queue. 110 * @mdev: pointer to &struct media_device, may be NULL. 111 * @b: buffer structure passed from userspace to 112 * &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver 113 * 114 * Should be called from &v4l2_ioctl_ops->vidioc_prepare_buf ioctl handler 115 * of a driver. 116 * 117 * This function: 118 * 119 * #) verifies the passed buffer, 120 * #) calls &vb2_ops->buf_prepare callback in the driver (if provided), 121 * in which driver-specific buffer initialization can be performed. 122 * #) if @b->request_fd is non-zero and @mdev->ops->req_queue is set, 123 * then bind the prepared buffer to the request. 124 * 125 * The return values from this function are intended to be directly returned 126 * from &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver. 127 */ 128 int vb2_prepare_buf(struct vb2_queue *q, struct media_device *mdev, 129 struct v4l2_buffer *b); 130 131 /** 132 * vb2_qbuf() - Queue a buffer from userspace 133 * @q: pointer to &struct vb2_queue with videobuf2 queue. 134 * @mdev: pointer to &struct media_device, may be NULL. 135 * @b: buffer structure passed from userspace to 136 * &v4l2_ioctl_ops->vidioc_qbuf handler in driver 137 * 138 * Should be called from &v4l2_ioctl_ops->vidioc_qbuf handler of a driver. 139 * 140 * This function: 141 * 142 * #) verifies the passed buffer; 143 * #) if @b->request_fd is non-zero and @mdev->ops->req_queue is set, 144 * then bind the buffer to the request. 145 * #) if necessary, calls &vb2_ops->buf_prepare callback in the driver 146 * (if provided), in which driver-specific buffer initialization can 147 * be performed; 148 * #) if streaming is on, queues the buffer in driver by the means of 149 * &vb2_ops->buf_queue callback for processing. 150 * 151 * The return values from this function are intended to be directly returned 152 * from &v4l2_ioctl_ops->vidioc_qbuf handler in driver. 153 */ 154 int vb2_qbuf(struct vb2_queue *q, struct media_device *mdev, 155 struct v4l2_buffer *b); 156 157 /** 158 * vb2_expbuf() - Export a buffer as a file descriptor 159 * @q: pointer to &struct vb2_queue with videobuf2 queue. 160 * @eb: export buffer structure passed from userspace to 161 * &v4l2_ioctl_ops->vidioc_expbuf handler in driver 162 * 163 * The return values from this function are intended to be directly returned 164 * from &v4l2_ioctl_ops->vidioc_expbuf handler in driver. 165 */ 166 int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb); 167 168 /** 169 * vb2_dqbuf() - Dequeue a buffer to the userspace 170 * @q: pointer to &struct vb2_queue with videobuf2 queue. 171 * @b: buffer structure passed from userspace to 172 * &v4l2_ioctl_ops->vidioc_dqbuf handler in driver 173 * @nonblocking: if true, this call will not sleep waiting for a buffer if no 174 * buffers ready for dequeuing are present. Normally the driver 175 * would be passing (&file->f_flags & %O_NONBLOCK) here 176 * 177 * Should be called from &v4l2_ioctl_ops->vidioc_dqbuf ioctl handler 178 * of a driver. 179 * 180 * This function: 181 * 182 * #) verifies the passed buffer; 183 * #) calls &vb2_ops->buf_finish callback in the driver (if provided), in which 184 * driver can perform any additional operations that may be required before 185 * returning the buffer to userspace, such as cache sync; 186 * #) the buffer struct members are filled with relevant information for 187 * the userspace. 188 * 189 * The return values from this function are intended to be directly returned 190 * from &v4l2_ioctl_ops->vidioc_dqbuf handler in driver. 191 */ 192 int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking); 193 194 /** 195 * vb2_streamon - start streaming 196 * @q: pointer to &struct vb2_queue with videobuf2 queue. 197 * @type: type argument passed from userspace to vidioc_streamon handler, 198 * as defined by &enum v4l2_buf_type. 199 * 200 * Should be called from &v4l2_ioctl_ops->vidioc_streamon handler of a driver. 201 * 202 * This function: 203 * 204 * 1) verifies current state 205 * 2) passes any previously queued buffers to the driver and starts streaming 206 * 207 * The return values from this function are intended to be directly returned 208 * from &v4l2_ioctl_ops->vidioc_streamon handler in the driver. 209 */ 210 int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type); 211 212 /** 213 * vb2_streamoff - stop streaming 214 * @q: pointer to &struct vb2_queue with videobuf2 queue. 215 * @type: type argument passed from userspace to vidioc_streamoff handler 216 * 217 * Should be called from vidioc_streamoff handler of a driver. 218 * 219 * This function: 220 * 221 * #) verifies current state, 222 * #) stop streaming and dequeues any queued buffers, including those previously 223 * passed to the driver (after waiting for the driver to finish). 224 * 225 * This call can be used for pausing playback. 226 * The return values from this function are intended to be directly returned 227 * from vidioc_streamoff handler in the driver 228 */ 229 int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type); 230 231 /** 232 * vb2_queue_init() - initialize a videobuf2 queue 233 * @q: pointer to &struct vb2_queue with videobuf2 queue. 234 * 235 * The vb2_queue structure should be allocated by the driver. The driver is 236 * responsible of clearing it's content and setting initial values for some 237 * required entries before calling this function. 238 * q->ops, q->mem_ops, q->type and q->io_modes are mandatory. Please refer 239 * to the struct vb2_queue description in include/media/videobuf2-core.h 240 * for more information. 241 */ 242 int __must_check vb2_queue_init(struct vb2_queue *q); 243 244 /** 245 * vb2_queue_init_name() - initialize a videobuf2 queue with a name 246 * @q: pointer to &struct vb2_queue with videobuf2 queue. 247 * @name: the queue name 248 * 249 * This function initializes the vb2_queue exactly like vb2_queue_init(), 250 * and additionally sets the queue name. The queue name is used for logging 251 * purpose, and should uniquely identify the queue within the context of the 252 * device it belongs to. This is useful to attribute kernel log messages to the 253 * right queue for m2m devices or other devices that handle multiple queues. 254 */ 255 int __must_check vb2_queue_init_name(struct vb2_queue *q, const char *name); 256 257 /** 258 * vb2_queue_release() - stop streaming, release the queue and free memory 259 * @q: pointer to &struct vb2_queue with videobuf2 queue. 260 * 261 * This function stops streaming and performs necessary clean ups, including 262 * freeing video buffer memory. The driver is responsible for freeing 263 * the vb2_queue structure itself. 264 */ 265 void vb2_queue_release(struct vb2_queue *q); 266 267 /** 268 * vb2_queue_change_type() - change the type of an inactive vb2_queue 269 * @q: pointer to &struct vb2_queue with videobuf2 queue. 270 * @type: the type to change to (V4L2_BUF_TYPE_VIDEO_*) 271 * 272 * This function changes the type of the vb2_queue. This is only possible 273 * if the queue is not busy (i.e. no buffers have been allocated). 274 * 275 * vb2_queue_change_type() can be used to support multiple buffer types using 276 * the same queue. The driver can implement v4l2_ioctl_ops.vidioc_reqbufs and 277 * v4l2_ioctl_ops.vidioc_create_bufs functions and call vb2_queue_change_type() 278 * before calling vb2_ioctl_reqbufs() or vb2_ioctl_create_bufs(), and thus 279 * "lock" the buffer type until the buffers have been released. 280 */ 281 int vb2_queue_change_type(struct vb2_queue *q, unsigned int type); 282 283 /** 284 * vb2_poll() - implements poll userspace operation 285 * @q: pointer to &struct vb2_queue with videobuf2 queue. 286 * @file: file argument passed to the poll file operation handler 287 * @wait: wait argument passed to the poll file operation handler 288 * 289 * This function implements poll file operation handler for a driver. 290 * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will 291 * be informed that the file descriptor of a video device is available for 292 * reading. 293 * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor 294 * will be reported as available for writing. 295 * 296 * If the driver uses struct v4l2_fh, then vb2_poll() will also check for any 297 * pending events. 298 * 299 * The return values from this function are intended to be directly returned 300 * from poll handler in driver. 301 */ 302 __poll_t vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait); 303 304 /* 305 * The following functions are not part of the vb2 core API, but are simple 306 * helper functions that you can use in your struct v4l2_file_operations, 307 * struct v4l2_ioctl_ops and struct vb2_ops. They will serialize if vb2_queue->lock 308 * or video_device->lock is set, and they will set and test vb2_queue->owner 309 * to check if the calling filehandle is permitted to do the queuing operation. 310 */ 311 312 /* struct v4l2_ioctl_ops helpers */ 313 314 int vb2_ioctl_reqbufs(struct file *file, void *priv, 315 struct v4l2_requestbuffers *p); 316 int vb2_ioctl_create_bufs(struct file *file, void *priv, 317 struct v4l2_create_buffers *p); 318 int vb2_ioctl_prepare_buf(struct file *file, void *priv, 319 struct v4l2_buffer *p); 320 int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p); 321 int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p); 322 int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p); 323 int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i); 324 int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i); 325 int vb2_ioctl_expbuf(struct file *file, void *priv, 326 struct v4l2_exportbuffer *p); 327 328 /* struct v4l2_file_operations helpers */ 329 330 int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma); 331 int vb2_fop_release(struct file *file); 332 int _vb2_fop_release(struct file *file, struct mutex *lock); 333 ssize_t vb2_fop_write(struct file *file, const char __user *buf, 334 size_t count, loff_t *ppos); 335 ssize_t vb2_fop_read(struct file *file, char __user *buf, 336 size_t count, loff_t *ppos); 337 __poll_t vb2_fop_poll(struct file *file, poll_table *wait); 338 #ifndef CONFIG_MMU 339 unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr, 340 unsigned long len, unsigned long pgoff, unsigned long flags); 341 #endif 342 343 /** 344 * vb2_video_unregister_device - unregister the video device and release queue 345 * 346 * @vdev: pointer to &struct video_device 347 * 348 * If the driver uses vb2_fop_release()/_vb2_fop_release(), then it should use 349 * vb2_video_unregister_device() instead of video_unregister_device(). 350 * 351 * This function will call video_unregister_device() and then release the 352 * vb2_queue if streaming is in progress. This will stop streaming and 353 * this will simplify the unbind sequence since after this call all subdevs 354 * will have stopped streaming as well. 355 */ 356 void vb2_video_unregister_device(struct video_device *vdev); 357 358 /** 359 * vb2_ops_wait_prepare - helper function to lock a struct &vb2_queue 360 * 361 * @vq: pointer to &struct vb2_queue 362 * 363 * ..note:: only use if vq->lock is non-NULL. 364 */ 365 void vb2_ops_wait_prepare(struct vb2_queue *vq); 366 367 /** 368 * vb2_ops_wait_finish - helper function to unlock a struct &vb2_queue 369 * 370 * @vq: pointer to &struct vb2_queue 371 * 372 * ..note:: only use if vq->lock is non-NULL. 373 */ 374 void vb2_ops_wait_finish(struct vb2_queue *vq); 375 376 struct media_request; 377 int vb2_request_validate(struct media_request *req); 378 void vb2_request_queue(struct media_request *req); 379 380 #endif /* _MEDIA_VIDEOBUF2_V4L2_H */ 381