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