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