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 /** 59 * vb2_find_timestamp() - Find buffer with given timestamp in the queue 60 * 61 * @q: pointer to &struct vb2_queue with videobuf2 queue. 62 * @timestamp: the timestamp to find. 63 * @start_idx: the start index (usually 0) in the buffer array to start 64 * searching from. Note that there may be multiple buffers 65 * with the same timestamp value, so you can restart the search 66 * by setting @start_idx to the previously found index + 1. 67 * 68 * Returns the buffer index of the buffer with the given @timestamp, or 69 * -1 if no buffer with @timestamp was found. 70 */ 71 int vb2_find_timestamp(const struct vb2_queue *q, u64 timestamp, 72 unsigned int start_idx); 73 74 int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b); 75 76 /** 77 * vb2_reqbufs() - Wrapper for vb2_core_reqbufs() that also verifies 78 * the memory and type values. 79 * 80 * @q: pointer to &struct vb2_queue with videobuf2 queue. 81 * @req: &struct v4l2_requestbuffers passed from userspace to 82 * &v4l2_ioctl_ops->vidioc_reqbufs handler in driver. 83 */ 84 int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req); 85 86 /** 87 * vb2_create_bufs() - Wrapper for vb2_core_create_bufs() that also verifies 88 * the memory and type values. 89 * 90 * @q: pointer to &struct vb2_queue with videobuf2 queue. 91 * @create: creation parameters, passed from userspace to 92 * &v4l2_ioctl_ops->vidioc_create_bufs handler in driver 93 */ 94 int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create); 95 96 /** 97 * vb2_prepare_buf() - Pass ownership of a buffer from userspace to the kernel 98 * 99 * @q: pointer to &struct vb2_queue with videobuf2 queue. 100 * @mdev: pointer to &struct media_device, may be NULL. 101 * @b: buffer structure passed from userspace to 102 * &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver 103 * 104 * Should be called from &v4l2_ioctl_ops->vidioc_prepare_buf ioctl handler 105 * of a driver. 106 * 107 * This function: 108 * 109 * #) verifies the passed buffer, 110 * #) calls &vb2_ops->buf_prepare callback in the driver (if provided), 111 * in which driver-specific buffer initialization can be performed. 112 * #) if @b->request_fd is non-zero and @mdev->ops->req_queue is set, 113 * then bind the prepared buffer to the request. 114 * 115 * The return values from this function are intended to be directly returned 116 * from &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver. 117 */ 118 int vb2_prepare_buf(struct vb2_queue *q, struct media_device *mdev, 119 struct v4l2_buffer *b); 120 121 /** 122 * vb2_qbuf() - Queue a buffer from userspace 123 * @q: pointer to &struct vb2_queue with videobuf2 queue. 124 * @mdev: pointer to &struct media_device, may be NULL. 125 * @b: buffer structure passed from userspace to 126 * &v4l2_ioctl_ops->vidioc_qbuf handler in driver 127 * 128 * Should be called from &v4l2_ioctl_ops->vidioc_qbuf handler of a driver. 129 * 130 * This function: 131 * 132 * #) verifies the passed buffer; 133 * #) if @b->request_fd is non-zero and @mdev->ops->req_queue is set, 134 * then bind the buffer to the request. 135 * #) if necessary, calls &vb2_ops->buf_prepare callback in the driver 136 * (if provided), in which driver-specific buffer initialization can 137 * be performed; 138 * #) if streaming is on, queues the buffer in driver by the means of 139 * &vb2_ops->buf_queue callback for processing. 140 * 141 * The return values from this function are intended to be directly returned 142 * from &v4l2_ioctl_ops->vidioc_qbuf handler in driver. 143 */ 144 int vb2_qbuf(struct vb2_queue *q, struct media_device *mdev, 145 struct v4l2_buffer *b); 146 147 /** 148 * vb2_expbuf() - Export a buffer as a file descriptor 149 * @q: pointer to &struct vb2_queue with videobuf2 queue. 150 * @eb: export buffer structure passed from userspace to 151 * &v4l2_ioctl_ops->vidioc_expbuf handler in driver 152 * 153 * The return values from this function are intended to be directly returned 154 * from &v4l2_ioctl_ops->vidioc_expbuf handler in driver. 155 */ 156 int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb); 157 158 /** 159 * vb2_dqbuf() - Dequeue a buffer to the userspace 160 * @q: pointer to &struct vb2_queue with videobuf2 queue. 161 * @b: buffer structure passed from userspace to 162 * &v4l2_ioctl_ops->vidioc_dqbuf handler in driver 163 * @nonblocking: if true, this call will not sleep waiting for a buffer if no 164 * buffers ready for dequeuing are present. Normally the driver 165 * would be passing (&file->f_flags & %O_NONBLOCK) here 166 * 167 * Should be called from &v4l2_ioctl_ops->vidioc_dqbuf ioctl handler 168 * of a driver. 169 * 170 * This function: 171 * 172 * #) verifies the passed buffer; 173 * #) calls &vb2_ops->buf_finish callback in the driver (if provided), in which 174 * driver can perform any additional operations that may be required before 175 * returning the buffer to userspace, such as cache sync; 176 * #) the buffer struct members are filled with relevant information for 177 * the userspace. 178 * 179 * The return values from this function are intended to be directly returned 180 * from &v4l2_ioctl_ops->vidioc_dqbuf handler in driver. 181 */ 182 int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking); 183 184 /** 185 * vb2_streamon - start streaming 186 * @q: pointer to &struct vb2_queue with videobuf2 queue. 187 * @type: type argument passed from userspace to vidioc_streamon handler, 188 * as defined by &enum v4l2_buf_type. 189 * 190 * Should be called from &v4l2_ioctl_ops->vidioc_streamon handler of a driver. 191 * 192 * This function: 193 * 194 * 1) verifies current state 195 * 2) passes any previously queued buffers to the driver and starts streaming 196 * 197 * The return values from this function are intended to be directly returned 198 * from &v4l2_ioctl_ops->vidioc_streamon handler in the driver. 199 */ 200 int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type); 201 202 /** 203 * vb2_streamoff - stop streaming 204 * @q: pointer to &struct vb2_queue with videobuf2 queue. 205 * @type: type argument passed from userspace to vidioc_streamoff handler 206 * 207 * Should be called from vidioc_streamoff handler of a driver. 208 * 209 * This function: 210 * 211 * #) verifies current state, 212 * #) stop streaming and dequeues any queued buffers, including those previously 213 * passed to the driver (after waiting for the driver to finish). 214 * 215 * This call can be used for pausing playback. 216 * The return values from this function are intended to be directly returned 217 * from vidioc_streamoff handler in the driver 218 */ 219 int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type); 220 221 /** 222 * vb2_queue_init() - initialize a videobuf2 queue 223 * @q: pointer to &struct vb2_queue with videobuf2 queue. 224 * 225 * The vb2_queue structure should be allocated by the driver. The driver is 226 * responsible of clearing it's content and setting initial values for some 227 * required entries before calling this function. 228 * q->ops, q->mem_ops, q->type and q->io_modes are mandatory. Please refer 229 * to the struct vb2_queue description in include/media/videobuf2-core.h 230 * for more information. 231 */ 232 int __must_check vb2_queue_init(struct vb2_queue *q); 233 234 /** 235 * vb2_queue_release() - stop streaming, release the queue and free memory 236 * @q: pointer to &struct vb2_queue with videobuf2 queue. 237 * 238 * This function stops streaming and performs necessary clean ups, including 239 * freeing video buffer memory. The driver is responsible for freeing 240 * the vb2_queue structure itself. 241 */ 242 void vb2_queue_release(struct vb2_queue *q); 243 244 /** 245 * vb2_poll() - implements poll userspace operation 246 * @q: pointer to &struct vb2_queue with videobuf2 queue. 247 * @file: file argument passed to the poll file operation handler 248 * @wait: wait argument passed to the poll file operation handler 249 * 250 * This function implements poll file operation handler for a driver. 251 * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will 252 * be informed that the file descriptor of a video device is available for 253 * reading. 254 * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor 255 * will be reported as available for writing. 256 * 257 * If the driver uses struct v4l2_fh, then vb2_poll() will also check for any 258 * pending events. 259 * 260 * The return values from this function are intended to be directly returned 261 * from poll handler in driver. 262 */ 263 __poll_t vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait); 264 265 /* 266 * The following functions are not part of the vb2 core API, but are simple 267 * helper functions that you can use in your struct v4l2_file_operations, 268 * struct v4l2_ioctl_ops and struct vb2_ops. They will serialize if vb2_queue->lock 269 * or video_device->lock is set, and they will set and test vb2_queue->owner 270 * to check if the calling filehandle is permitted to do the queuing operation. 271 */ 272 273 /* struct v4l2_ioctl_ops helpers */ 274 275 int vb2_ioctl_reqbufs(struct file *file, void *priv, 276 struct v4l2_requestbuffers *p); 277 int vb2_ioctl_create_bufs(struct file *file, void *priv, 278 struct v4l2_create_buffers *p); 279 int vb2_ioctl_prepare_buf(struct file *file, void *priv, 280 struct v4l2_buffer *p); 281 int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p); 282 int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p); 283 int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p); 284 int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i); 285 int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i); 286 int vb2_ioctl_expbuf(struct file *file, void *priv, 287 struct v4l2_exportbuffer *p); 288 289 /* struct v4l2_file_operations helpers */ 290 291 int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma); 292 int vb2_fop_release(struct file *file); 293 int _vb2_fop_release(struct file *file, struct mutex *lock); 294 ssize_t vb2_fop_write(struct file *file, const char __user *buf, 295 size_t count, loff_t *ppos); 296 ssize_t vb2_fop_read(struct file *file, char __user *buf, 297 size_t count, loff_t *ppos); 298 __poll_t vb2_fop_poll(struct file *file, poll_table *wait); 299 #ifndef CONFIG_MMU 300 unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr, 301 unsigned long len, unsigned long pgoff, unsigned long flags); 302 #endif 303 304 /** 305 * vb2_ops_wait_prepare - helper function to lock a struct &vb2_queue 306 * 307 * @vq: pointer to &struct vb2_queue 308 * 309 * ..note:: only use if vq->lock is non-NULL. 310 */ 311 void vb2_ops_wait_prepare(struct vb2_queue *vq); 312 313 /** 314 * vb2_ops_wait_finish - helper function to unlock a struct &vb2_queue 315 * 316 * @vq: pointer to &struct vb2_queue 317 * 318 * ..note:: only use if vq->lock is non-NULL. 319 */ 320 void vb2_ops_wait_finish(struct vb2_queue *vq); 321 322 struct media_request; 323 int vb2_request_validate(struct media_request *req); 324 void vb2_request_queue(struct media_request *req); 325 326 #endif /* _MEDIA_VIDEOBUF2_V4L2_H */ 327