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. Additional gfp_flags to use when allocating the 31 * are also passed to this operation. These flags are from the 32 * gfp_flags field of vb2_queue. 33 * @put: inform the allocator that the buffer will no longer be used; 34 * usually will result in the allocator freeing the buffer (if 35 * no other users of this buffer are present); the buf_priv 36 * argument is the allocator private per-buffer structure 37 * previously returned from the alloc callback 38 * @get_userptr: acquire userspace memory for a hardware operation; used for 39 * USERPTR memory types; vaddr is the address passed to the 40 * videobuf layer when queuing a video buffer of USERPTR type; 41 * should return an allocator private per-buffer structure 42 * associated with the buffer on success, NULL on failure; 43 * the returned private structure will then be passed as buf_priv 44 * argument to other ops in this structure 45 * @put_userptr: inform the allocator that a USERPTR buffer will no longer 46 * be used 47 * @attach_dmabuf: attach a shared struct dma_buf for a hardware operation; 48 * used for DMABUF memory types; alloc_ctx is the alloc context 49 * dbuf is the shared dma_buf; returns NULL on failure; 50 * allocator private per-buffer structure on success; 51 * this needs to be used for further accesses to the buffer 52 * @detach_dmabuf: inform the exporter of the buffer that the current DMABUF 53 * buffer is no longer used; the buf_priv argument is the 54 * allocator private per-buffer structure previously returned 55 * from the attach_dmabuf callback 56 * @map_dmabuf: request for access to the dmabuf from allocator; the allocator 57 * of dmabuf is informed that this driver is going to use the 58 * dmabuf 59 * @unmap_dmabuf: releases access control to the dmabuf - allocator is notified 60 * that this driver is done using the dmabuf for now 61 * @prepare: called every time the buffer is passed from userspace to the 62 * driver, useful for cache synchronisation, optional 63 * @finish: called every time the buffer is passed back from the driver 64 * to the userspace, also optional 65 * @vaddr: return a kernel virtual address to a given memory buffer 66 * associated with the passed private structure or NULL if no 67 * such mapping exists 68 * @cookie: return allocator specific cookie for a given memory buffer 69 * associated with the passed private structure or NULL if not 70 * available 71 * @num_users: return the current number of users of a memory buffer; 72 * return 1 if the videobuf layer (or actually the driver using 73 * it) is the only user 74 * @mmap: setup a userspace mapping for a given memory buffer under 75 * the provided virtual memory region 76 * 77 * Required ops for USERPTR types: get_userptr, put_userptr. 78 * Required ops for MMAP types: alloc, put, num_users, mmap. 79 * Required ops for read/write access types: alloc, put, num_users, vaddr 80 * Required ops for DMABUF types: attach_dmabuf, detach_dmabuf, map_dmabuf, 81 * unmap_dmabuf. 82 */ 83 struct vb2_mem_ops { 84 void *(*alloc)(void *alloc_ctx, unsigned long size, gfp_t gfp_flags); 85 void (*put)(void *buf_priv); 86 struct dma_buf *(*get_dmabuf)(void *buf_priv, unsigned long flags); 87 88 void *(*get_userptr)(void *alloc_ctx, unsigned long vaddr, 89 unsigned long size, int write); 90 void (*put_userptr)(void *buf_priv); 91 92 void (*prepare)(void *buf_priv); 93 void (*finish)(void *buf_priv); 94 95 void *(*attach_dmabuf)(void *alloc_ctx, struct dma_buf *dbuf, 96 unsigned long size, int write); 97 void (*detach_dmabuf)(void *buf_priv); 98 int (*map_dmabuf)(void *buf_priv); 99 void (*unmap_dmabuf)(void *buf_priv); 100 101 void *(*vaddr)(void *buf_priv); 102 void *(*cookie)(void *buf_priv); 103 104 unsigned int (*num_users)(void *buf_priv); 105 106 int (*mmap)(void *buf_priv, struct vm_area_struct *vma); 107 }; 108 109 struct vb2_plane { 110 void *mem_priv; 111 struct dma_buf *dbuf; 112 unsigned int dbuf_mapped; 113 }; 114 115 /** 116 * enum vb2_io_modes - queue access methods 117 * @VB2_MMAP: driver supports MMAP with streaming API 118 * @VB2_USERPTR: driver supports USERPTR with streaming API 119 * @VB2_READ: driver supports read() style access 120 * @VB2_WRITE: driver supports write() style access 121 * @VB2_DMABUF: driver supports DMABUF with streaming API 122 */ 123 enum vb2_io_modes { 124 VB2_MMAP = (1 << 0), 125 VB2_USERPTR = (1 << 1), 126 VB2_READ = (1 << 2), 127 VB2_WRITE = (1 << 3), 128 VB2_DMABUF = (1 << 4), 129 }; 130 131 /** 132 * enum vb2_fileio_flags - flags for selecting a mode of the file io emulator, 133 * by default the 'streaming' style is used by the file io emulator 134 * @VB2_FILEIO_READ_ONCE: report EOF after reading the first buffer 135 * @VB2_FILEIO_WRITE_IMMEDIATELY: queue buffer after each write() call 136 */ 137 enum vb2_fileio_flags { 138 VB2_FILEIO_READ_ONCE = (1 << 0), 139 VB2_FILEIO_WRITE_IMMEDIATELY = (1 << 1), 140 }; 141 142 /** 143 * enum vb2_buffer_state - current video buffer state 144 * @VB2_BUF_STATE_DEQUEUED: buffer under userspace control 145 * @VB2_BUF_STATE_PREPARING: buffer is being prepared in videobuf 146 * @VB2_BUF_STATE_PREPARED: buffer prepared in videobuf and by the driver 147 * @VB2_BUF_STATE_QUEUED: buffer queued in videobuf, but not in driver 148 * @VB2_BUF_STATE_ACTIVE: buffer queued in driver and possibly used 149 * in a hardware operation 150 * @VB2_BUF_STATE_DONE: buffer returned from driver to videobuf, but 151 * not yet dequeued to userspace 152 * @VB2_BUF_STATE_ERROR: same as above, but the operation on the buffer 153 * has ended with an error, which will be reported 154 * to the userspace when it is dequeued 155 */ 156 enum vb2_buffer_state { 157 VB2_BUF_STATE_DEQUEUED, 158 VB2_BUF_STATE_PREPARING, 159 VB2_BUF_STATE_PREPARED, 160 VB2_BUF_STATE_QUEUED, 161 VB2_BUF_STATE_ACTIVE, 162 VB2_BUF_STATE_DONE, 163 VB2_BUF_STATE_ERROR, 164 }; 165 166 struct vb2_queue; 167 168 /** 169 * struct vb2_buffer - represents a video buffer 170 * @v4l2_buf: struct v4l2_buffer 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 timestamp) 174 * @v4l2_planes: struct v4l2_planes associated with this buffer; can 175 * be read by the driver and relevant entries can be 176 * changed by the driver in case of CAPTURE types 177 * (such as bytesused); NOTE that even for single-planar 178 * types, the v4l2_planes[0] struct should be used 179 * instead of v4l2_buf for filling bytesused - drivers 180 * should use the vb2_set_plane_payload() function for that 181 * @vb2_queue: the queue to which this driver belongs 182 * @num_planes: number of planes in the buffer 183 * on an internal driver queue 184 * @state: current buffer state; do not change 185 * @queued_entry: entry on the queued buffers list, which holds all 186 * buffers queued from userspace 187 * @done_entry: entry on the list that stores all buffers ready to 188 * be dequeued to userspace 189 * @planes: private per-plane information; do not change 190 */ 191 struct vb2_buffer { 192 struct v4l2_buffer v4l2_buf; 193 struct v4l2_plane v4l2_planes[VIDEO_MAX_PLANES]; 194 195 struct vb2_queue *vb2_queue; 196 197 unsigned int num_planes; 198 199 /* Private: internal use only */ 200 enum vb2_buffer_state state; 201 202 struct list_head queued_entry; 203 struct list_head done_entry; 204 205 struct vb2_plane planes[VIDEO_MAX_PLANES]; 206 }; 207 208 /** 209 * struct vb2_ops - driver-specific callbacks 210 * 211 * @queue_setup: called from VIDIOC_REQBUFS and VIDIOC_CREATE_BUFS 212 * handlers before memory allocation, or, if 213 * *num_planes != 0, after the allocation to verify a 214 * smaller number of buffers. Driver should return 215 * the required number of buffers in *num_buffers, the 216 * required number of planes per buffer in *num_planes; the 217 * size of each plane should be set in the sizes[] array 218 * and optional per-plane allocator specific context in the 219 * alloc_ctxs[] array. When called from VIDIOC_REQBUFS, 220 * fmt == NULL, the driver has to use the currently 221 * configured format and *num_buffers is the total number 222 * of buffers, that are being allocated. When called from 223 * VIDIOC_CREATE_BUFS, fmt != NULL and it describes the 224 * target frame format (if the format isn't valid the 225 * callback must return -EINVAL). In this case *num_buffers 226 * are being allocated additionally to q->num_buffers. 227 * @wait_prepare: release any locks taken while calling vb2 functions; 228 * it is called before an ioctl needs to wait for a new 229 * buffer to arrive; required to avoid a deadlock in 230 * blocking access type 231 * @wait_finish: reacquire all locks released in the previous callback; 232 * required to continue operation after sleeping while 233 * waiting for a new buffer to arrive 234 * @buf_init: called once after allocating a buffer (in MMAP case) 235 * or after acquiring a new USERPTR buffer; drivers may 236 * perform additional buffer-related initialization; 237 * initialization failure (return != 0) will prevent 238 * queue setup from completing successfully; optional 239 * @buf_prepare: called every time the buffer is queued from userspace 240 * and from the VIDIOC_PREPARE_BUF ioctl; drivers may 241 * perform any initialization required before each hardware 242 * operation in this callback; drivers that support 243 * VIDIOC_CREATE_BUFS must also validate the buffer size; 244 * if an error is returned, the buffer will not be queued 245 * in driver; optional 246 * @buf_finish: called before every dequeue of the buffer back to 247 * userspace; drivers may perform any operations required 248 * before userspace accesses the buffer; optional 249 * @buf_cleanup: called once before the buffer is freed; drivers may 250 * perform any additional cleanup; optional 251 * @start_streaming: called once to enter 'streaming' state; the driver may 252 * receive buffers with @buf_queue callback before 253 * @start_streaming is called; the driver gets the number 254 * of already queued buffers in count parameter; driver 255 * can return an error if hardware fails, in that case all 256 * buffers that have been already given by the @buf_queue 257 * callback are invalidated. 258 * If there were not enough queued buffers to start 259 * streaming, then this callback returns -ENOBUFS, and the 260 * vb2 core will retry calling @start_streaming when a new 261 * buffer is queued. 262 * @stop_streaming: called when 'streaming' state must be disabled; driver 263 * should stop any DMA transactions or wait until they 264 * finish and give back all buffers it got from buf_queue() 265 * callback; may use vb2_wait_for_all_buffers() function 266 * @buf_queue: passes buffer vb to the driver; driver may start 267 * hardware operation on this buffer; driver should give 268 * the buffer back by calling vb2_buffer_done() function; 269 * it is allways called after calling STREAMON ioctl; 270 * might be called before start_streaming callback if user 271 * pre-queued buffers before calling STREAMON 272 */ 273 struct vb2_ops { 274 int (*queue_setup)(struct vb2_queue *q, const struct v4l2_format *fmt, 275 unsigned int *num_buffers, unsigned int *num_planes, 276 unsigned int sizes[], void *alloc_ctxs[]); 277 278 void (*wait_prepare)(struct vb2_queue *q); 279 void (*wait_finish)(struct vb2_queue *q); 280 281 int (*buf_init)(struct vb2_buffer *vb); 282 int (*buf_prepare)(struct vb2_buffer *vb); 283 int (*buf_finish)(struct vb2_buffer *vb); 284 void (*buf_cleanup)(struct vb2_buffer *vb); 285 286 int (*start_streaming)(struct vb2_queue *q, unsigned int count); 287 int (*stop_streaming)(struct vb2_queue *q); 288 289 void (*buf_queue)(struct vb2_buffer *vb); 290 }; 291 292 struct v4l2_fh; 293 294 /** 295 * struct vb2_queue - a videobuf queue 296 * 297 * @type: queue type (see V4L2_BUF_TYPE_* in linux/videodev2.h 298 * @io_modes: supported io methods (see vb2_io_modes enum) 299 * @io_flags: additional io flags (see vb2_fileio_flags enum) 300 * @lock: pointer to a mutex that protects the vb2_queue struct. The 301 * driver can set this to a mutex to let the v4l2 core serialize 302 * the queuing ioctls. If the driver wants to handle locking 303 * itself, then this should be set to NULL. This lock is not used 304 * by the videobuf2 core API. 305 * @owner: The filehandle that 'owns' the buffers, i.e. the filehandle 306 * that called reqbufs, create_buffers or started fileio. 307 * This field is not used by the videobuf2 core API, but it allows 308 * drivers to easily associate an owner filehandle with the queue. 309 * @ops: driver-specific callbacks 310 * @mem_ops: memory allocator specific callbacks 311 * @drv_priv: driver private data 312 * @buf_struct_size: size of the driver-specific buffer structure; 313 * "0" indicates the driver doesn't want to use a custom buffer 314 * structure type, so sizeof(struct vb2_buffer) will is used 315 * @gfp_flags: additional gfp flags used when allocating the buffers. 316 * Typically this is 0, but it may be e.g. GFP_DMA or __GFP_DMA32 317 * to force the buffer allocation to a specific memory zone. 318 * 319 * @memory: current memory type used 320 * @bufs: videobuf buffer structures 321 * @num_buffers: number of allocated/used buffers 322 * @queued_list: list of buffers currently queued from userspace 323 * @queued_count: number of buffers owned by the driver 324 * @done_list: list of buffers ready to be dequeued to userspace 325 * @done_lock: lock to protect done_list list 326 * @done_wq: waitqueue for processes waiting for buffers ready to be dequeued 327 * @alloc_ctx: memory type/allocator-specific contexts for each plane 328 * @streaming: current streaming state 329 * @retry_start_streaming: start_streaming() was called, but there were not enough 330 * buffers queued. If set, then retry calling start_streaming when 331 * queuing a new buffer. 332 * @fileio: file io emulator internal data, used only if emulator is active 333 */ 334 struct vb2_queue { 335 enum v4l2_buf_type type; 336 unsigned int io_modes; 337 unsigned int io_flags; 338 struct mutex *lock; 339 struct v4l2_fh *owner; 340 341 const struct vb2_ops *ops; 342 const struct vb2_mem_ops *mem_ops; 343 void *drv_priv; 344 unsigned int buf_struct_size; 345 u32 timestamp_type; 346 gfp_t gfp_flags; 347 348 /* private: internal use only */ 349 enum v4l2_memory memory; 350 struct vb2_buffer *bufs[VIDEO_MAX_FRAME]; 351 unsigned int num_buffers; 352 353 struct list_head queued_list; 354 355 atomic_t queued_count; 356 struct list_head done_list; 357 spinlock_t done_lock; 358 wait_queue_head_t done_wq; 359 360 void *alloc_ctx[VIDEO_MAX_PLANES]; 361 unsigned int plane_sizes[VIDEO_MAX_PLANES]; 362 363 unsigned int streaming:1; 364 unsigned int retry_start_streaming:1; 365 366 struct vb2_fileio_data *fileio; 367 }; 368 369 void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no); 370 void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no); 371 372 void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state); 373 int vb2_wait_for_all_buffers(struct vb2_queue *q); 374 375 int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b); 376 int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req); 377 378 int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create); 379 int vb2_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b); 380 381 int __must_check vb2_queue_init(struct vb2_queue *q); 382 383 void vb2_queue_release(struct vb2_queue *q); 384 385 int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b); 386 int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb); 387 int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking); 388 389 int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type); 390 int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type); 391 392 int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma); 393 #ifndef CONFIG_MMU 394 unsigned long vb2_get_unmapped_area(struct vb2_queue *q, 395 unsigned long addr, 396 unsigned long len, 397 unsigned long pgoff, 398 unsigned long flags); 399 #endif 400 unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait); 401 size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count, 402 loff_t *ppos, int nonblock); 403 size_t vb2_write(struct vb2_queue *q, const char __user *data, size_t count, 404 loff_t *ppos, int nonblock); 405 406 /** 407 * vb2_is_streaming() - return streaming status of the queue 408 * @q: videobuf queue 409 */ 410 static inline bool vb2_is_streaming(struct vb2_queue *q) 411 { 412 return q->streaming; 413 } 414 415 /** 416 * vb2_is_busy() - return busy status of the queue 417 * @q: videobuf queue 418 * 419 * This function checks if queue has any buffers allocated. 420 */ 421 static inline bool vb2_is_busy(struct vb2_queue *q) 422 { 423 return (q->num_buffers > 0); 424 } 425 426 /** 427 * vb2_get_drv_priv() - return driver private data associated with the queue 428 * @q: videobuf queue 429 */ 430 static inline void *vb2_get_drv_priv(struct vb2_queue *q) 431 { 432 return q->drv_priv; 433 } 434 435 /** 436 * vb2_set_plane_payload() - set bytesused for the plane plane_no 437 * @vb: buffer for which plane payload should be set 438 * @plane_no: plane number for which payload should be set 439 * @size: payload in bytes 440 */ 441 static inline void vb2_set_plane_payload(struct vb2_buffer *vb, 442 unsigned int plane_no, unsigned long size) 443 { 444 if (plane_no < vb->num_planes) 445 vb->v4l2_planes[plane_no].bytesused = size; 446 } 447 448 /** 449 * vb2_get_plane_payload() - get bytesused for the plane plane_no 450 * @vb: buffer for which plane payload should be set 451 * @plane_no: plane number for which payload should be set 452 * @size: payload in bytes 453 */ 454 static inline unsigned long vb2_get_plane_payload(struct vb2_buffer *vb, 455 unsigned int plane_no) 456 { 457 if (plane_no < vb->num_planes) 458 return vb->v4l2_planes[plane_no].bytesused; 459 return 0; 460 } 461 462 /** 463 * vb2_plane_size() - return plane size in bytes 464 * @vb: buffer for which plane size should be returned 465 * @plane_no: plane number for which size should be returned 466 */ 467 static inline unsigned long 468 vb2_plane_size(struct vb2_buffer *vb, unsigned int plane_no) 469 { 470 if (plane_no < vb->num_planes) 471 return vb->v4l2_planes[plane_no].length; 472 return 0; 473 } 474 475 /* 476 * The following functions are not part of the vb2 core API, but are simple 477 * helper functions that you can use in your struct v4l2_file_operations, 478 * struct v4l2_ioctl_ops and struct vb2_ops. They will serialize if vb2_queue->lock 479 * or video_device->lock is set, and they will set and test vb2_queue->owner 480 * to check if the calling filehandle is permitted to do the queuing operation. 481 */ 482 483 /* struct v4l2_ioctl_ops helpers */ 484 485 int vb2_ioctl_reqbufs(struct file *file, void *priv, 486 struct v4l2_requestbuffers *p); 487 int vb2_ioctl_create_bufs(struct file *file, void *priv, 488 struct v4l2_create_buffers *p); 489 int vb2_ioctl_prepare_buf(struct file *file, void *priv, 490 struct v4l2_buffer *p); 491 int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p); 492 int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p); 493 int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p); 494 int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i); 495 int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i); 496 int vb2_ioctl_expbuf(struct file *file, void *priv, 497 struct v4l2_exportbuffer *p); 498 499 /* struct v4l2_file_operations helpers */ 500 501 int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma); 502 int vb2_fop_release(struct file *file); 503 int _vb2_fop_release(struct file *file, struct mutex *lock); 504 ssize_t vb2_fop_write(struct file *file, const char __user *buf, 505 size_t count, loff_t *ppos); 506 ssize_t vb2_fop_read(struct file *file, char __user *buf, 507 size_t count, loff_t *ppos); 508 unsigned int vb2_fop_poll(struct file *file, poll_table *wait); 509 #ifndef CONFIG_MMU 510 unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr, 511 unsigned long len, unsigned long pgoff, unsigned long flags); 512 #endif 513 514 /* struct vb2_ops helpers, only use if vq->lock is non-NULL. */ 515 516 void vb2_ops_wait_prepare(struct vb2_queue *vq); 517 void vb2_ops_wait_finish(struct vb2_queue *vq); 518 519 #endif /* _MEDIA_VIDEOBUF2_CORE_H */ 520