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