1 /* 2 * videobuf2-core.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_CORE_H 13 #define _MEDIA_VIDEOBUF2_CORE_H 14 15 #include <linux/mm_types.h> 16 #include <linux/mutex.h> 17 #include <linux/poll.h> 18 #include <linux/videodev2.h> 19 #include <linux/dma-buf.h> 20 21 struct vb2_alloc_ctx; 22 struct vb2_fileio_data; 23 24 /** 25 * struct vb2_mem_ops - memory handling/memory allocator operations 26 * @alloc: allocate video memory and, optionally, allocator private data, 27 * return NULL on failure or a pointer to allocator private, 28 * per-buffer data on success; the returned private structure 29 * will then be passed as buf_priv argument to other ops in this 30 * structure 31 * @put: inform the allocator that the buffer will no longer be used; 32 * usually will result in the allocator freeing the buffer (if 33 * no other users of this buffer are present); the buf_priv 34 * argument is the allocator private per-buffer structure 35 * previously returned from the alloc callback 36 * @get_userptr: acquire userspace memory for a hardware operation; used for 37 * USERPTR memory types; vaddr is the address passed to the 38 * videobuf layer when queuing a video buffer of USERPTR type; 39 * should return an allocator private per-buffer structure 40 * associated with the buffer on success, NULL on failure; 41 * the returned private structure will then be passed as buf_priv 42 * argument to other ops in this structure 43 * @put_userptr: inform the allocator that a USERPTR buffer will no longer 44 * be used 45 * @attach_dmabuf: attach a shared struct dma_buf for a hardware operation; 46 * used for DMABUF memory types; alloc_ctx is the alloc context 47 * dbuf is the shared dma_buf; returns NULL on failure; 48 * allocator private per-buffer structure on success; 49 * this needs to be used for further accesses to the buffer 50 * @detach_dmabuf: inform the exporter of the buffer that the current DMABUF 51 * buffer is no longer used; the buf_priv argument is the 52 * allocator private per-buffer structure previously returned 53 * from the attach_dmabuf callback 54 * @map_dmabuf: request for access to the dmabuf from allocator; the allocator 55 * of dmabuf is informed that this driver is going to use the 56 * dmabuf 57 * @unmap_dmabuf: releases access control to the dmabuf - allocator is notified 58 * that this driver is done using the dmabuf for now 59 * @prepare: called every time the buffer is passed from userspace to the 60 * driver, useful for cache synchronisation, optional 61 * @finish: called every time the buffer is passed back from the driver 62 * to the userspace, also optional 63 * @vaddr: return a kernel virtual address to a given memory buffer 64 * associated with the passed private structure or NULL if no 65 * such mapping exists 66 * @cookie: return allocator specific cookie for a given memory buffer 67 * associated with the passed private structure or NULL if not 68 * available 69 * @num_users: return the current number of users of a memory buffer; 70 * return 1 if the videobuf layer (or actually the driver using 71 * it) is the only user 72 * @mmap: setup a userspace mapping for a given memory buffer under 73 * the provided virtual memory region 74 * 75 * Required ops for USERPTR types: get_userptr, put_userptr. 76 * Required ops for MMAP types: alloc, put, num_users, mmap. 77 * Required ops for read/write access types: alloc, put, num_users, vaddr 78 * Required ops for DMABUF types: attach_dmabuf, detach_dmabuf, map_dmabuf, 79 * unmap_dmabuf. 80 */ 81 struct vb2_mem_ops { 82 void *(*alloc)(void *alloc_ctx, unsigned long size); 83 void (*put)(void *buf_priv); 84 struct dma_buf *(*get_dmabuf)(void *buf_priv); 85 86 void *(*get_userptr)(void *alloc_ctx, unsigned long vaddr, 87 unsigned long size, int write); 88 void (*put_userptr)(void *buf_priv); 89 90 void (*prepare)(void *buf_priv); 91 void (*finish)(void *buf_priv); 92 93 void *(*attach_dmabuf)(void *alloc_ctx, struct dma_buf *dbuf, 94 unsigned long size, int write); 95 void (*detach_dmabuf)(void *buf_priv); 96 int (*map_dmabuf)(void *buf_priv); 97 void (*unmap_dmabuf)(void *buf_priv); 98 99 void *(*vaddr)(void *buf_priv); 100 void *(*cookie)(void *buf_priv); 101 102 unsigned int (*num_users)(void *buf_priv); 103 104 int (*mmap)(void *buf_priv, struct vm_area_struct *vma); 105 }; 106 107 struct vb2_plane { 108 void *mem_priv; 109 struct dma_buf *dbuf; 110 unsigned int dbuf_mapped; 111 }; 112 113 /** 114 * enum vb2_io_modes - queue access methods 115 * @VB2_MMAP: driver supports MMAP with streaming API 116 * @VB2_USERPTR: driver supports USERPTR with streaming API 117 * @VB2_READ: driver supports read() style access 118 * @VB2_WRITE: driver supports write() style access 119 * @VB2_DMABUF: driver supports DMABUF with streaming API 120 */ 121 enum vb2_io_modes { 122 VB2_MMAP = (1 << 0), 123 VB2_USERPTR = (1 << 1), 124 VB2_READ = (1 << 2), 125 VB2_WRITE = (1 << 3), 126 VB2_DMABUF = (1 << 4), 127 }; 128 129 /** 130 * enum vb2_fileio_flags - flags for selecting a mode of the file io emulator, 131 * by default the 'streaming' style is used by the file io emulator 132 * @VB2_FILEIO_READ_ONCE: report EOF after reading the first buffer 133 * @VB2_FILEIO_WRITE_IMMEDIATELY: queue buffer after each write() call 134 */ 135 enum vb2_fileio_flags { 136 VB2_FILEIO_READ_ONCE = (1 << 0), 137 VB2_FILEIO_WRITE_IMMEDIATELY = (1 << 1), 138 }; 139 140 /** 141 * enum vb2_buffer_state - current video buffer state 142 * @VB2_BUF_STATE_DEQUEUED: buffer under userspace control 143 * @VB2_BUF_STATE_PREPARED: buffer prepared in videobuf and by the driver 144 * @VB2_BUF_STATE_QUEUED: buffer queued in videobuf, but not in driver 145 * @VB2_BUF_STATE_ACTIVE: buffer queued in driver and possibly used 146 * in a hardware operation 147 * @VB2_BUF_STATE_DONE: buffer returned from driver to videobuf, but 148 * not yet dequeued to userspace 149 * @VB2_BUF_STATE_ERROR: same as above, but the operation on the buffer 150 * has ended with an error, which will be reported 151 * to the userspace when it is dequeued 152 */ 153 enum vb2_buffer_state { 154 VB2_BUF_STATE_DEQUEUED, 155 VB2_BUF_STATE_PREPARED, 156 VB2_BUF_STATE_QUEUED, 157 VB2_BUF_STATE_ACTIVE, 158 VB2_BUF_STATE_DONE, 159 VB2_BUF_STATE_ERROR, 160 }; 161 162 struct vb2_queue; 163 164 /** 165 * struct vb2_buffer - represents a video buffer 166 * @v4l2_buf: struct v4l2_buffer associated with this buffer; can 167 * be read by the driver and relevant entries can be 168 * changed by the driver in case of CAPTURE types 169 * (such as timestamp) 170 * @v4l2_planes: struct v4l2_planes associated with this buffer; can 171 * be read by the driver and relevant entries can be 172 * changed by the driver in case of CAPTURE types 173 * (such as bytesused); NOTE that even for single-planar 174 * types, the v4l2_planes[0] struct should be used 175 * instead of v4l2_buf for filling bytesused - drivers 176 * should use the vb2_set_plane_payload() function for that 177 * @vb2_queue: the queue to which this driver belongs 178 * @num_planes: number of planes in the buffer 179 * on an internal driver queue 180 * @state: current buffer state; do not change 181 * @queued_entry: entry on the queued buffers list, which holds all 182 * buffers queued from userspace 183 * @done_entry: entry on the list that stores all buffers ready to 184 * be dequeued to userspace 185 * @planes: private per-plane information; do not change 186 */ 187 struct vb2_buffer { 188 struct v4l2_buffer v4l2_buf; 189 struct v4l2_plane v4l2_planes[VIDEO_MAX_PLANES]; 190 191 struct vb2_queue *vb2_queue; 192 193 unsigned int num_planes; 194 195 /* Private: internal use only */ 196 enum vb2_buffer_state state; 197 198 struct list_head queued_entry; 199 struct list_head done_entry; 200 201 struct vb2_plane planes[VIDEO_MAX_PLANES]; 202 }; 203 204 /** 205 * struct vb2_ops - driver-specific callbacks 206 * 207 * @queue_setup: called from VIDIOC_REQBUFS and VIDIOC_CREATE_BUFS 208 * handlers before memory allocation, or, if 209 * *num_planes != 0, after the allocation to verify a 210 * smaller number of buffers. Driver should return 211 * the required number of buffers in *num_buffers, the 212 * required number of planes per buffer in *num_planes; the 213 * size of each plane should be set in the sizes[] array 214 * and optional per-plane allocator specific context in the 215 * alloc_ctxs[] array. When called from VIDIOC_REQBUFS, 216 * fmt == NULL, the driver has to use the currently 217 * configured format and *num_buffers is the total number 218 * of buffers, that are being allocated. When called from 219 * VIDIOC_CREATE_BUFS, fmt != NULL and it describes the 220 * target frame format. In this case *num_buffers are being 221 * allocated additionally to q->num_buffers. 222 * @wait_prepare: release any locks taken while calling vb2 functions; 223 * it is called before an ioctl needs to wait for a new 224 * buffer to arrive; required to avoid a deadlock in 225 * blocking access type 226 * @wait_finish: reacquire all locks released in the previous callback; 227 * required to continue operation after sleeping while 228 * waiting for a new buffer to arrive 229 * @buf_init: called once after allocating a buffer (in MMAP case) 230 * or after acquiring a new USERPTR buffer; drivers may 231 * perform additional buffer-related initialization; 232 * initialization failure (return != 0) will prevent 233 * queue setup from completing successfully; optional 234 * @buf_prepare: called every time the buffer is queued from userspace 235 * and from the VIDIOC_PREPARE_BUF ioctl; drivers may 236 * perform any initialization required before each hardware 237 * operation in this callback; if an error is returned, the 238 * buffer will not be queued in driver; optional 239 * @buf_finish: called before every dequeue of the buffer back to 240 * userspace; drivers may perform any operations required 241 * before userspace accesses the buffer; optional 242 * @buf_cleanup: called once before the buffer is freed; drivers may 243 * perform any additional cleanup; optional 244 * @start_streaming: called once to enter 'streaming' state; the driver may 245 * receive buffers with @buf_queue callback before 246 * @start_streaming is called; the driver gets the number 247 * of already queued buffers in count parameter; driver 248 * can return an error if hardware fails or not enough 249 * buffers has been queued, in such case all buffers that 250 * have been already given by the @buf_queue callback are 251 * invalidated. 252 * @stop_streaming: called when 'streaming' state must be disabled; driver 253 * should stop any DMA transactions or wait until they 254 * finish and give back all buffers it got from buf_queue() 255 * callback; may use vb2_wait_for_all_buffers() function 256 * @buf_queue: passes buffer vb to the driver; driver may start 257 * hardware operation on this buffer; driver should give 258 * the buffer back by calling vb2_buffer_done() function; 259 * it is allways called after calling STREAMON ioctl; 260 * might be called before start_streaming callback if user 261 * pre-queued buffers before calling STREAMON 262 */ 263 struct vb2_ops { 264 int (*queue_setup)(struct vb2_queue *q, const struct v4l2_format *fmt, 265 unsigned int *num_buffers, unsigned int *num_planes, 266 unsigned int sizes[], void *alloc_ctxs[]); 267 268 void (*wait_prepare)(struct vb2_queue *q); 269 void (*wait_finish)(struct vb2_queue *q); 270 271 int (*buf_init)(struct vb2_buffer *vb); 272 int (*buf_prepare)(struct vb2_buffer *vb); 273 int (*buf_finish)(struct vb2_buffer *vb); 274 void (*buf_cleanup)(struct vb2_buffer *vb); 275 276 int (*start_streaming)(struct vb2_queue *q, unsigned int count); 277 int (*stop_streaming)(struct vb2_queue *q); 278 279 void (*buf_queue)(struct vb2_buffer *vb); 280 }; 281 282 struct v4l2_fh; 283 284 /** 285 * struct vb2_queue - a videobuf queue 286 * 287 * @type: queue type (see V4L2_BUF_TYPE_* in linux/videodev2.h 288 * @io_modes: supported io methods (see vb2_io_modes enum) 289 * @io_flags: additional io flags (see vb2_fileio_flags enum) 290 * @lock: pointer to a mutex that protects the vb2_queue struct. The 291 * driver can set this to a mutex to let the v4l2 core serialize 292 * the queuing ioctls. If the driver wants to handle locking 293 * itself, then this should be set to NULL. This lock is not used 294 * by the videobuf2 core API. 295 * @owner: The filehandle that 'owns' the buffers, i.e. the filehandle 296 * that called reqbufs, create_buffers or started fileio. 297 * This field is not used by the videobuf2 core API, but it allows 298 * drivers to easily associate an owner filehandle with the queue. 299 * @ops: driver-specific callbacks 300 * @mem_ops: memory allocator specific callbacks 301 * @drv_priv: driver private data 302 * @buf_struct_size: size of the driver-specific buffer structure; 303 * "0" indicates the driver doesn't want to use a custom buffer 304 * structure type, so sizeof(struct vb2_buffer) will is used 305 * 306 * @memory: current memory type used 307 * @bufs: videobuf buffer structures 308 * @num_buffers: number of allocated/used buffers 309 * @queued_list: list of buffers currently queued from userspace 310 * @queued_count: number of buffers owned by the driver 311 * @done_list: list of buffers ready to be dequeued to userspace 312 * @done_lock: lock to protect done_list list 313 * @done_wq: waitqueue for processes waiting for buffers ready to be dequeued 314 * @alloc_ctx: memory type/allocator-specific contexts for each plane 315 * @streaming: current streaming state 316 * @fileio: file io emulator internal data, used only if emulator is active 317 */ 318 struct vb2_queue { 319 enum v4l2_buf_type type; 320 unsigned int io_modes; 321 unsigned int io_flags; 322 struct mutex *lock; 323 struct v4l2_fh *owner; 324 325 const struct vb2_ops *ops; 326 const struct vb2_mem_ops *mem_ops; 327 void *drv_priv; 328 unsigned int buf_struct_size; 329 330 /* private: internal use only */ 331 enum v4l2_memory memory; 332 struct vb2_buffer *bufs[VIDEO_MAX_FRAME]; 333 unsigned int num_buffers; 334 335 struct list_head queued_list; 336 337 atomic_t queued_count; 338 struct list_head done_list; 339 spinlock_t done_lock; 340 wait_queue_head_t done_wq; 341 342 void *alloc_ctx[VIDEO_MAX_PLANES]; 343 unsigned int plane_sizes[VIDEO_MAX_PLANES]; 344 345 unsigned int streaming:1; 346 347 struct vb2_fileio_data *fileio; 348 }; 349 350 void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no); 351 void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no); 352 353 void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state); 354 int vb2_wait_for_all_buffers(struct vb2_queue *q); 355 356 int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b); 357 int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req); 358 359 int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create); 360 int vb2_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b); 361 362 int __must_check vb2_queue_init(struct vb2_queue *q); 363 364 void vb2_queue_release(struct vb2_queue *q); 365 366 int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b); 367 int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb); 368 int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking); 369 370 int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type); 371 int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type); 372 373 int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma); 374 #ifndef CONFIG_MMU 375 unsigned long vb2_get_unmapped_area(struct vb2_queue *q, 376 unsigned long addr, 377 unsigned long len, 378 unsigned long pgoff, 379 unsigned long flags); 380 #endif 381 unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait); 382 size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count, 383 loff_t *ppos, int nonblock); 384 size_t vb2_write(struct vb2_queue *q, char __user *data, size_t count, 385 loff_t *ppos, int nonblock); 386 387 /** 388 * vb2_is_streaming() - return streaming status of the queue 389 * @q: videobuf queue 390 */ 391 static inline bool vb2_is_streaming(struct vb2_queue *q) 392 { 393 return q->streaming; 394 } 395 396 /** 397 * vb2_is_busy() - return busy status of the queue 398 * @q: videobuf queue 399 * 400 * This function checks if queue has any buffers allocated. 401 */ 402 static inline bool vb2_is_busy(struct vb2_queue *q) 403 { 404 return (q->num_buffers > 0); 405 } 406 407 /** 408 * vb2_get_drv_priv() - return driver private data associated with the queue 409 * @q: videobuf queue 410 */ 411 static inline void *vb2_get_drv_priv(struct vb2_queue *q) 412 { 413 return q->drv_priv; 414 } 415 416 /** 417 * vb2_set_plane_payload() - set bytesused for the plane plane_no 418 * @vb: buffer for which plane payload should be set 419 * @plane_no: plane number for which payload should be set 420 * @size: payload in bytes 421 */ 422 static inline void vb2_set_plane_payload(struct vb2_buffer *vb, 423 unsigned int plane_no, unsigned long size) 424 { 425 if (plane_no < vb->num_planes) 426 vb->v4l2_planes[plane_no].bytesused = size; 427 } 428 429 /** 430 * vb2_get_plane_payload() - get bytesused for the plane plane_no 431 * @vb: buffer for which plane payload should be set 432 * @plane_no: plane number for which payload should be set 433 * @size: payload in bytes 434 */ 435 static inline unsigned long vb2_get_plane_payload(struct vb2_buffer *vb, 436 unsigned int plane_no) 437 { 438 if (plane_no < vb->num_planes) 439 return vb->v4l2_planes[plane_no].bytesused; 440 return 0; 441 } 442 443 /** 444 * vb2_plane_size() - return plane size in bytes 445 * @vb: buffer for which plane size should be returned 446 * @plane_no: plane number for which size should be returned 447 */ 448 static inline unsigned long 449 vb2_plane_size(struct vb2_buffer *vb, unsigned int plane_no) 450 { 451 if (plane_no < vb->num_planes) 452 return vb->v4l2_planes[plane_no].length; 453 return 0; 454 } 455 456 /* 457 * The following functions are not part of the vb2 core API, but are simple 458 * helper functions that you can use in your struct v4l2_file_operations, 459 * struct v4l2_ioctl_ops and struct vb2_ops. They will serialize if vb2_queue->lock 460 * or video_device->lock is set, and they will set and test vb2_queue->owner 461 * to check if the calling filehandle is permitted to do the queuing operation. 462 */ 463 464 /* struct v4l2_ioctl_ops helpers */ 465 466 int vb2_ioctl_reqbufs(struct file *file, void *priv, 467 struct v4l2_requestbuffers *p); 468 int vb2_ioctl_create_bufs(struct file *file, void *priv, 469 struct v4l2_create_buffers *p); 470 int vb2_ioctl_prepare_buf(struct file *file, void *priv, 471 struct v4l2_buffer *p); 472 int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p); 473 int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p); 474 int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p); 475 int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i); 476 int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i); 477 int vb2_ioctl_expbuf(struct file *file, void *priv, 478 struct v4l2_exportbuffer *p); 479 480 /* struct v4l2_file_operations helpers */ 481 482 int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma); 483 int vb2_fop_release(struct file *file); 484 ssize_t vb2_fop_write(struct file *file, char __user *buf, 485 size_t count, loff_t *ppos); 486 ssize_t vb2_fop_read(struct file *file, char __user *buf, 487 size_t count, loff_t *ppos); 488 unsigned int vb2_fop_poll(struct file *file, poll_table *wait); 489 #ifndef CONFIG_MMU 490 unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr, 491 unsigned long len, unsigned long pgoff, unsigned long flags); 492 #endif 493 494 /* struct vb2_ops helpers, only use if vq->lock is non-NULL. */ 495 496 void vb2_ops_wait_prepare(struct vb2_queue *vq); 497 void vb2_ops_wait_finish(struct vb2_queue *vq); 498 499 #endif /* _MEDIA_VIDEOBUF2_CORE_H */ 500