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_buffer() - Find a buffer with given timestamp 67 * 68 * @q: pointer to &struct vb2_queue with videobuf2 queue. 69 * @timestamp: the timestamp to find. 70 * 71 * Returns the buffer with the given @timestamp, or NULL if not found. 72 */ 73 struct vb2_buffer *vb2_find_buffer(struct vb2_queue *q, u64 timestamp); 74 75 int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b); 76 77 /** 78 * vb2_reqbufs() - Wrapper for vb2_core_reqbufs() that also verifies 79 * the memory and type values. 80 * 81 * @q: pointer to &struct vb2_queue with videobuf2 queue. 82 * @req: &struct v4l2_requestbuffers passed from userspace to 83 * &v4l2_ioctl_ops->vidioc_reqbufs handler in driver. 84 */ 85 int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req); 86 87 /** 88 * vb2_create_bufs() - Wrapper for vb2_core_create_bufs() that also verifies 89 * the memory and type values. 90 * 91 * @q: pointer to &struct vb2_queue with videobuf2 queue. 92 * @create: creation parameters, passed from userspace to 93 * &v4l2_ioctl_ops->vidioc_create_bufs handler in driver 94 */ 95 int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create); 96 97 /** 98 * vb2_prepare_buf() - Pass ownership of a buffer from userspace to the kernel 99 * 100 * @q: pointer to &struct vb2_queue with videobuf2 queue. 101 * @mdev: pointer to &struct media_device, may be NULL. 102 * @b: buffer structure passed from userspace to 103 * &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver 104 * 105 * Should be called from &v4l2_ioctl_ops->vidioc_prepare_buf ioctl handler 106 * of a driver. 107 * 108 * This function: 109 * 110 * #) verifies the passed buffer, 111 * #) calls &vb2_ops->buf_prepare callback in the driver (if provided), 112 * in which driver-specific buffer initialization can be performed. 113 * #) if @b->request_fd is non-zero and @mdev->ops->req_queue is set, 114 * then bind the prepared buffer to the request. 115 * 116 * The return values from this function are intended to be directly returned 117 * from &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver. 118 */ 119 int vb2_prepare_buf(struct vb2_queue *q, struct media_device *mdev, 120 struct v4l2_buffer *b); 121 122 /** 123 * vb2_qbuf() - Queue a buffer from userspace 124 * @q: pointer to &struct vb2_queue with videobuf2 queue. 125 * @mdev: pointer to &struct media_device, may be NULL. 126 * @b: buffer structure passed from userspace to 127 * &v4l2_ioctl_ops->vidioc_qbuf handler in driver 128 * 129 * Should be called from &v4l2_ioctl_ops->vidioc_qbuf handler of a driver. 130 * 131 * This function: 132 * 133 * #) verifies the passed buffer; 134 * #) if @b->request_fd is non-zero and @mdev->ops->req_queue is set, 135 * then bind the buffer to the request. 136 * #) if necessary, calls &vb2_ops->buf_prepare callback in the driver 137 * (if provided), in which driver-specific buffer initialization can 138 * be performed; 139 * #) if streaming is on, queues the buffer in driver by the means of 140 * &vb2_ops->buf_queue callback for processing. 141 * 142 * The return values from this function are intended to be directly returned 143 * from &v4l2_ioctl_ops->vidioc_qbuf handler in driver. 144 */ 145 int vb2_qbuf(struct vb2_queue *q, struct media_device *mdev, 146 struct v4l2_buffer *b); 147 148 /** 149 * vb2_expbuf() - Export a buffer as a file descriptor 150 * @q: pointer to &struct vb2_queue with videobuf2 queue. 151 * @eb: export buffer structure passed from userspace to 152 * &v4l2_ioctl_ops->vidioc_expbuf handler in driver 153 * 154 * The return values from this function are intended to be directly returned 155 * from &v4l2_ioctl_ops->vidioc_expbuf handler in driver. 156 */ 157 int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb); 158 159 /** 160 * vb2_dqbuf() - Dequeue a buffer to the userspace 161 * @q: pointer to &struct vb2_queue with videobuf2 queue. 162 * @b: buffer structure passed from userspace to 163 * &v4l2_ioctl_ops->vidioc_dqbuf handler in driver 164 * @nonblocking: if true, this call will not sleep waiting for a buffer if no 165 * buffers ready for dequeuing are present. Normally the driver 166 * would be passing (&file->f_flags & %O_NONBLOCK) here 167 * 168 * Should be called from &v4l2_ioctl_ops->vidioc_dqbuf ioctl handler 169 * of a driver. 170 * 171 * This function: 172 * 173 * #) verifies the passed buffer; 174 * #) calls &vb2_ops->buf_finish callback in the driver (if provided), in which 175 * driver can perform any additional operations that may be required before 176 * returning the buffer to userspace, such as cache sync; 177 * #) the buffer struct members are filled with relevant information for 178 * the userspace. 179 * 180 * The return values from this function are intended to be directly returned 181 * from &v4l2_ioctl_ops->vidioc_dqbuf handler in driver. 182 */ 183 int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking); 184 185 /** 186 * vb2_streamon - start streaming 187 * @q: pointer to &struct vb2_queue with videobuf2 queue. 188 * @type: type argument passed from userspace to vidioc_streamon handler, 189 * as defined by &enum v4l2_buf_type. 190 * 191 * Should be called from &v4l2_ioctl_ops->vidioc_streamon handler of a driver. 192 * 193 * This function: 194 * 195 * 1) verifies current state 196 * 2) passes any previously queued buffers to the driver and starts streaming 197 * 198 * The return values from this function are intended to be directly returned 199 * from &v4l2_ioctl_ops->vidioc_streamon handler in the driver. 200 */ 201 int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type); 202 203 /** 204 * vb2_streamoff - stop streaming 205 * @q: pointer to &struct vb2_queue with videobuf2 queue. 206 * @type: type argument passed from userspace to vidioc_streamoff handler 207 * 208 * Should be called from vidioc_streamoff handler of a driver. 209 * 210 * This function: 211 * 212 * #) verifies current state, 213 * #) stop streaming and dequeues any queued buffers, including those previously 214 * passed to the driver (after waiting for the driver to finish). 215 * 216 * This call can be used for pausing playback. 217 * The return values from this function are intended to be directly returned 218 * from vidioc_streamoff handler in the driver 219 */ 220 int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type); 221 222 /** 223 * vb2_queue_init() - initialize a videobuf2 queue 224 * @q: pointer to &struct vb2_queue with videobuf2 queue. 225 * 226 * The vb2_queue structure should be allocated by the driver. The driver is 227 * responsible of clearing it's content and setting initial values for some 228 * required entries before calling this function. 229 * q->ops, q->mem_ops, q->type and q->io_modes are mandatory. Please refer 230 * to the struct vb2_queue description in include/media/videobuf2-core.h 231 * for more information. 232 */ 233 int __must_check vb2_queue_init(struct vb2_queue *q); 234 235 /** 236 * vb2_queue_init_name() - initialize a videobuf2 queue with a name 237 * @q: pointer to &struct vb2_queue with videobuf2 queue. 238 * @name: the queue name 239 * 240 * This function initializes the vb2_queue exactly like vb2_queue_init(), 241 * and additionally sets the queue name. The queue name is used for logging 242 * purpose, and should uniquely identify the queue within the context of the 243 * device it belongs to. This is useful to attribute kernel log messages to the 244 * right queue for m2m devices or other devices that handle multiple queues. 245 */ 246 int __must_check vb2_queue_init_name(struct vb2_queue *q, const char *name); 247 248 /** 249 * vb2_queue_release() - stop streaming, release the queue and free memory 250 * @q: pointer to &struct vb2_queue with videobuf2 queue. 251 * 252 * This function stops streaming and performs necessary clean ups, including 253 * freeing video buffer memory. The driver is responsible for freeing 254 * the vb2_queue structure itself. 255 */ 256 void vb2_queue_release(struct vb2_queue *q); 257 258 /** 259 * vb2_queue_change_type() - change the type of an inactive vb2_queue 260 * @q: pointer to &struct vb2_queue with videobuf2 queue. 261 * @type: the type to change to (V4L2_BUF_TYPE_VIDEO_*) 262 * 263 * This function changes the type of the vb2_queue. This is only possible 264 * if the queue is not busy (i.e. no buffers have been allocated). 265 * 266 * vb2_queue_change_type() can be used to support multiple buffer types using 267 * the same queue. The driver can implement v4l2_ioctl_ops.vidioc_reqbufs and 268 * v4l2_ioctl_ops.vidioc_create_bufs functions and call vb2_queue_change_type() 269 * before calling vb2_ioctl_reqbufs() or vb2_ioctl_create_bufs(), and thus 270 * "lock" the buffer type until the buffers have been released. 271 */ 272 int vb2_queue_change_type(struct vb2_queue *q, unsigned int type); 273 274 /** 275 * vb2_poll() - implements poll userspace operation 276 * @q: pointer to &struct vb2_queue with videobuf2 queue. 277 * @file: file argument passed to the poll file operation handler 278 * @wait: wait argument passed to the poll file operation handler 279 * 280 * This function implements poll file operation handler for a driver. 281 * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will 282 * be informed that the file descriptor of a video device is available for 283 * reading. 284 * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor 285 * will be reported as available for writing. 286 * 287 * If the driver uses struct v4l2_fh, then vb2_poll() will also check for any 288 * pending events. 289 * 290 * The return values from this function are intended to be directly returned 291 * from poll handler in driver. 292 */ 293 __poll_t vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait); 294 295 /* 296 * The following functions are not part of the vb2 core API, but are simple 297 * helper functions that you can use in your struct v4l2_file_operations, 298 * struct v4l2_ioctl_ops and struct vb2_ops. They will serialize if vb2_queue->lock 299 * or video_device->lock is set, and they will set and test the queue owner 300 * (vb2_queue->owner) to check if the calling filehandle is permitted to do the 301 * queuing operation. 302 */ 303 304 /** 305 * vb2_queue_is_busy() - check if the queue is busy 306 * @q: pointer to &struct vb2_queue with videobuf2 queue. 307 * @file: file through which the vb2 queue access is performed 308 * 309 * The queue is considered busy if it has an owner and the owner is not the 310 * @file. 311 * 312 * Queue ownership is acquired and checked by some of the v4l2_ioctl_ops helpers 313 * below. Drivers can also use this function directly when they need to 314 * open-code ioctl handlers, for instance to add additional checks between the 315 * queue ownership test and the call to the corresponding vb2 operation. 316 */ 317 static inline bool vb2_queue_is_busy(struct vb2_queue *q, struct file *file) 318 { 319 return q->owner && q->owner != file->private_data; 320 } 321 322 /* struct v4l2_ioctl_ops helpers */ 323 324 int vb2_ioctl_reqbufs(struct file *file, void *priv, 325 struct v4l2_requestbuffers *p); 326 int vb2_ioctl_create_bufs(struct file *file, void *priv, 327 struct v4l2_create_buffers *p); 328 int vb2_ioctl_prepare_buf(struct file *file, void *priv, 329 struct v4l2_buffer *p); 330 int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p); 331 int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p); 332 int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p); 333 int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i); 334 int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i); 335 int vb2_ioctl_expbuf(struct file *file, void *priv, 336 struct v4l2_exportbuffer *p); 337 338 /* struct v4l2_file_operations helpers */ 339 340 int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma); 341 int vb2_fop_release(struct file *file); 342 int _vb2_fop_release(struct file *file, struct mutex *lock); 343 ssize_t vb2_fop_write(struct file *file, const char __user *buf, 344 size_t count, loff_t *ppos); 345 ssize_t vb2_fop_read(struct file *file, char __user *buf, 346 size_t count, loff_t *ppos); 347 __poll_t vb2_fop_poll(struct file *file, poll_table *wait); 348 #ifndef CONFIG_MMU 349 unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr, 350 unsigned long len, unsigned long pgoff, unsigned long flags); 351 #endif 352 353 /** 354 * vb2_video_unregister_device - unregister the video device and release queue 355 * 356 * @vdev: pointer to &struct video_device 357 * 358 * If the driver uses vb2_fop_release()/_vb2_fop_release(), then it should use 359 * vb2_video_unregister_device() instead of video_unregister_device(). 360 * 361 * This function will call video_unregister_device() and then release the 362 * vb2_queue if streaming is in progress. This will stop streaming and 363 * this will simplify the unbind sequence since after this call all subdevs 364 * will have stopped streaming as well. 365 */ 366 void vb2_video_unregister_device(struct video_device *vdev); 367 368 /** 369 * vb2_ops_wait_prepare - helper function to lock a struct &vb2_queue 370 * 371 * @vq: pointer to &struct vb2_queue 372 * 373 * ..note:: only use if vq->lock is non-NULL. 374 */ 375 void vb2_ops_wait_prepare(struct vb2_queue *vq); 376 377 /** 378 * vb2_ops_wait_finish - helper function to unlock a struct &vb2_queue 379 * 380 * @vq: pointer to &struct vb2_queue 381 * 382 * ..note:: only use if vq->lock is non-NULL. 383 */ 384 void vb2_ops_wait_finish(struct vb2_queue *vq); 385 386 struct media_request; 387 int vb2_request_validate(struct media_request *req); 388 void vb2_request_queue(struct media_request *req); 389 390 #endif /* _MEDIA_VIDEOBUF2_V4L2_H */ 391