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_PREPARED: buffer prepared in videobuf and by the driver 146 * @VB2_BUF_STATE_QUEUED: buffer queued in videobuf, but not in driver 147 * @VB2_BUF_STATE_ACTIVE: buffer queued in driver and possibly used 148 * in a hardware operation 149 * @VB2_BUF_STATE_DONE: buffer returned from driver to videobuf, but 150 * not yet dequeued to userspace 151 * @VB2_BUF_STATE_ERROR: same as above, but the operation on the buffer 152 * has ended with an error, which will be reported 153 * to the userspace when it is dequeued 154 */ 155 enum vb2_buffer_state { 156 VB2_BUF_STATE_DEQUEUED, 157 VB2_BUF_STATE_PREPARED, 158 VB2_BUF_STATE_QUEUED, 159 VB2_BUF_STATE_ACTIVE, 160 VB2_BUF_STATE_DONE, 161 VB2_BUF_STATE_ERROR, 162 }; 163 164 struct vb2_queue; 165 166 /** 167 * struct vb2_buffer - represents a video buffer 168 * @v4l2_buf: struct v4l2_buffer associated with this buffer; can 169 * be read by the driver and relevant entries can be 170 * changed by the driver in case of CAPTURE types 171 * (such as timestamp) 172 * @v4l2_planes: struct v4l2_planes associated with this buffer; can 173 * be read by the driver and relevant entries can be 174 * changed by the driver in case of CAPTURE types 175 * (such as bytesused); NOTE that even for single-planar 176 * types, the v4l2_planes[0] struct should be used 177 * instead of v4l2_buf for filling bytesused - drivers 178 * should use the vb2_set_plane_payload() function for that 179 * @vb2_queue: the queue to which this driver belongs 180 * @num_planes: number of planes in the buffer 181 * on an internal driver queue 182 * @state: current buffer state; do not change 183 * @queued_entry: entry on the queued buffers list, which holds all 184 * buffers queued from userspace 185 * @done_entry: entry on the list that stores all buffers ready to 186 * be dequeued to userspace 187 * @planes: private per-plane information; do not change 188 */ 189 struct vb2_buffer { 190 struct v4l2_buffer v4l2_buf; 191 struct v4l2_plane v4l2_planes[VIDEO_MAX_PLANES]; 192 193 struct vb2_queue *vb2_queue; 194 195 unsigned int num_planes; 196 197 /* Private: internal use only */ 198 enum vb2_buffer_state state; 199 200 struct list_head queued_entry; 201 struct list_head done_entry; 202 203 struct vb2_plane planes[VIDEO_MAX_PLANES]; 204 }; 205 206 /** 207 * struct vb2_ops - driver-specific callbacks 208 * 209 * @queue_setup: called from VIDIOC_REQBUFS and VIDIOC_CREATE_BUFS 210 * handlers before memory allocation, or, if 211 * *num_planes != 0, after the allocation to verify a 212 * smaller number of buffers. Driver should return 213 * the required number of buffers in *num_buffers, the 214 * required number of planes per buffer in *num_planes; the 215 * size of each plane should be set in the sizes[] array 216 * and optional per-plane allocator specific context in the 217 * alloc_ctxs[] array. When called from VIDIOC_REQBUFS, 218 * fmt == NULL, the driver has to use the currently 219 * configured format and *num_buffers is the total number 220 * of buffers, that are being allocated. When called from 221 * VIDIOC_CREATE_BUFS, fmt != NULL and it describes the 222 * target frame format (if the format isn't valid the 223 * callback must return -EINVAL). In this case *num_buffers 224 * are being allocated additionally to q->num_buffers. 225 * @wait_prepare: release any locks taken while calling vb2 functions; 226 * it is called before an ioctl needs to wait for a new 227 * buffer to arrive; required to avoid a deadlock in 228 * blocking access type 229 * @wait_finish: reacquire all locks released in the previous callback; 230 * required to continue operation after sleeping while 231 * waiting for a new buffer to arrive 232 * @buf_init: called once after allocating a buffer (in MMAP case) 233 * or after acquiring a new USERPTR buffer; drivers may 234 * perform additional buffer-related initialization; 235 * initialization failure (return != 0) will prevent 236 * queue setup from completing successfully; optional 237 * @buf_prepare: called every time the buffer is queued from userspace 238 * and from the VIDIOC_PREPARE_BUF ioctl; drivers may 239 * perform any initialization required before each hardware 240 * operation in this callback; drivers that support 241 * VIDIOC_CREATE_BUFS must also validate the buffer size; 242 * if an error is returned, the buffer will not be queued 243 * in driver; optional 244 * @buf_finish: called before every dequeue of the buffer back to 245 * userspace; drivers may perform any operations required 246 * before userspace accesses the buffer; optional 247 * @buf_cleanup: called once before the buffer is freed; drivers may 248 * perform any additional cleanup; optional 249 * @start_streaming: called once to enter 'streaming' state; the driver may 250 * receive buffers with @buf_queue callback before 251 * @start_streaming is called; the driver gets the number 252 * of already queued buffers in count parameter; driver 253 * can return an error if hardware fails or not enough 254 * buffers has been queued, in such case all buffers that 255 * have been already given by the @buf_queue callback are 256 * invalidated. 257 * @stop_streaming: called when 'streaming' state must be disabled; driver 258 * should stop any DMA transactions or wait until they 259 * finish and give back all buffers it got from buf_queue() 260 * callback; may use vb2_wait_for_all_buffers() function 261 * @buf_queue: passes buffer vb to the driver; driver may start 262 * hardware operation on this buffer; driver should give 263 * the buffer back by calling vb2_buffer_done() function; 264 * it is allways called after calling STREAMON ioctl; 265 * might be called before start_streaming callback if user 266 * pre-queued buffers before calling STREAMON 267 */ 268 struct vb2_ops { 269 int (*queue_setup)(struct vb2_queue *q, const struct v4l2_format *fmt, 270 unsigned int *num_buffers, unsigned int *num_planes, 271 unsigned int sizes[], void *alloc_ctxs[]); 272 273 void (*wait_prepare)(struct vb2_queue *q); 274 void (*wait_finish)(struct vb2_queue *q); 275 276 int (*buf_init)(struct vb2_buffer *vb); 277 int (*buf_prepare)(struct vb2_buffer *vb); 278 int (*buf_finish)(struct vb2_buffer *vb); 279 void (*buf_cleanup)(struct vb2_buffer *vb); 280 281 int (*start_streaming)(struct vb2_queue *q, unsigned int count); 282 int (*stop_streaming)(struct vb2_queue *q); 283 284 void (*buf_queue)(struct vb2_buffer *vb); 285 }; 286 287 struct v4l2_fh; 288 289 /** 290 * struct vb2_queue - a videobuf queue 291 * 292 * @type: queue type (see V4L2_BUF_TYPE_* in linux/videodev2.h 293 * @io_modes: supported io methods (see vb2_io_modes enum) 294 * @io_flags: additional io flags (see vb2_fileio_flags enum) 295 * @lock: pointer to a mutex that protects the vb2_queue struct. The 296 * driver can set this to a mutex to let the v4l2 core serialize 297 * the queuing ioctls. If the driver wants to handle locking 298 * itself, then this should be set to NULL. This lock is not used 299 * by the videobuf2 core API. 300 * @owner: The filehandle that 'owns' the buffers, i.e. the filehandle 301 * that called reqbufs, create_buffers or started fileio. 302 * This field is not used by the videobuf2 core API, but it allows 303 * drivers to easily associate an owner filehandle with the queue. 304 * @ops: driver-specific callbacks 305 * @mem_ops: memory allocator specific callbacks 306 * @drv_priv: driver private data 307 * @buf_struct_size: size of the driver-specific buffer structure; 308 * "0" indicates the driver doesn't want to use a custom buffer 309 * structure type, so sizeof(struct vb2_buffer) will is used 310 * @gfp_flags: additional gfp flags used when allocating the buffers. 311 * Typically this is 0, but it may be e.g. GFP_DMA or __GFP_DMA32 312 * to force the buffer allocation to a specific memory zone. 313 * 314 * @memory: current memory type used 315 * @bufs: videobuf buffer structures 316 * @num_buffers: number of allocated/used buffers 317 * @queued_list: list of buffers currently queued from userspace 318 * @queued_count: number of buffers owned by the driver 319 * @done_list: list of buffers ready to be dequeued to userspace 320 * @done_lock: lock to protect done_list list 321 * @done_wq: waitqueue for processes waiting for buffers ready to be dequeued 322 * @alloc_ctx: memory type/allocator-specific contexts for each plane 323 * @streaming: current streaming state 324 * @fileio: file io emulator internal data, used only if emulator is active 325 */ 326 struct vb2_queue { 327 enum v4l2_buf_type type; 328 unsigned int io_modes; 329 unsigned int io_flags; 330 struct mutex *lock; 331 struct v4l2_fh *owner; 332 333 const struct vb2_ops *ops; 334 const struct vb2_mem_ops *mem_ops; 335 void *drv_priv; 336 unsigned int buf_struct_size; 337 u32 timestamp_type; 338 gfp_t gfp_flags; 339 340 /* private: internal use only */ 341 enum v4l2_memory memory; 342 struct vb2_buffer *bufs[VIDEO_MAX_FRAME]; 343 unsigned int num_buffers; 344 345 struct list_head queued_list; 346 347 atomic_t queued_count; 348 struct list_head done_list; 349 spinlock_t done_lock; 350 wait_queue_head_t done_wq; 351 352 void *alloc_ctx[VIDEO_MAX_PLANES]; 353 unsigned int plane_sizes[VIDEO_MAX_PLANES]; 354 355 unsigned int streaming:1; 356 357 struct vb2_fileio_data *fileio; 358 }; 359 360 void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no); 361 void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no); 362 363 void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state); 364 int vb2_wait_for_all_buffers(struct vb2_queue *q); 365 366 int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b); 367 int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req); 368 369 int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create); 370 int vb2_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b); 371 372 int __must_check vb2_queue_init(struct vb2_queue *q); 373 374 void vb2_queue_release(struct vb2_queue *q); 375 376 int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b); 377 int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb); 378 int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking); 379 380 int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type); 381 int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type); 382 383 int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma); 384 #ifndef CONFIG_MMU 385 unsigned long vb2_get_unmapped_area(struct vb2_queue *q, 386 unsigned long addr, 387 unsigned long len, 388 unsigned long pgoff, 389 unsigned long flags); 390 #endif 391 unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait); 392 size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count, 393 loff_t *ppos, int nonblock); 394 size_t vb2_write(struct vb2_queue *q, const char __user *data, size_t count, 395 loff_t *ppos, int nonblock); 396 397 /** 398 * vb2_is_streaming() - return streaming status of the queue 399 * @q: videobuf queue 400 */ 401 static inline bool vb2_is_streaming(struct vb2_queue *q) 402 { 403 return q->streaming; 404 } 405 406 /** 407 * vb2_is_busy() - return busy status of the queue 408 * @q: videobuf queue 409 * 410 * This function checks if queue has any buffers allocated. 411 */ 412 static inline bool vb2_is_busy(struct vb2_queue *q) 413 { 414 return (q->num_buffers > 0); 415 } 416 417 /** 418 * vb2_get_drv_priv() - return driver private data associated with the queue 419 * @q: videobuf queue 420 */ 421 static inline void *vb2_get_drv_priv(struct vb2_queue *q) 422 { 423 return q->drv_priv; 424 } 425 426 /** 427 * vb2_set_plane_payload() - set bytesused for the plane plane_no 428 * @vb: buffer for which plane payload should be set 429 * @plane_no: plane number for which payload should be set 430 * @size: payload in bytes 431 */ 432 static inline void vb2_set_plane_payload(struct vb2_buffer *vb, 433 unsigned int plane_no, unsigned long size) 434 { 435 if (plane_no < vb->num_planes) 436 vb->v4l2_planes[plane_no].bytesused = size; 437 } 438 439 /** 440 * vb2_get_plane_payload() - get bytesused for the plane plane_no 441 * @vb: buffer for which plane payload should be set 442 * @plane_no: plane number for which payload should be set 443 * @size: payload in bytes 444 */ 445 static inline unsigned long vb2_get_plane_payload(struct vb2_buffer *vb, 446 unsigned int plane_no) 447 { 448 if (plane_no < vb->num_planes) 449 return vb->v4l2_planes[plane_no].bytesused; 450 return 0; 451 } 452 453 /** 454 * vb2_plane_size() - return plane size in bytes 455 * @vb: buffer for which plane size should be returned 456 * @plane_no: plane number for which size should be returned 457 */ 458 static inline unsigned long 459 vb2_plane_size(struct vb2_buffer *vb, unsigned int plane_no) 460 { 461 if (plane_no < vb->num_planes) 462 return vb->v4l2_planes[plane_no].length; 463 return 0; 464 } 465 466 /* 467 * The following functions are not part of the vb2 core API, but are simple 468 * helper functions that you can use in your struct v4l2_file_operations, 469 * struct v4l2_ioctl_ops and struct vb2_ops. They will serialize if vb2_queue->lock 470 * or video_device->lock is set, and they will set and test vb2_queue->owner 471 * to check if the calling filehandle is permitted to do the queuing operation. 472 */ 473 474 /* struct v4l2_ioctl_ops helpers */ 475 476 int vb2_ioctl_reqbufs(struct file *file, void *priv, 477 struct v4l2_requestbuffers *p); 478 int vb2_ioctl_create_bufs(struct file *file, void *priv, 479 struct v4l2_create_buffers *p); 480 int vb2_ioctl_prepare_buf(struct file *file, void *priv, 481 struct v4l2_buffer *p); 482 int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p); 483 int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p); 484 int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p); 485 int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i); 486 int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i); 487 int vb2_ioctl_expbuf(struct file *file, void *priv, 488 struct v4l2_exportbuffer *p); 489 490 /* struct v4l2_file_operations helpers */ 491 492 int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma); 493 int vb2_fop_release(struct file *file); 494 ssize_t vb2_fop_write(struct file *file, const char __user *buf, 495 size_t count, loff_t *ppos); 496 ssize_t vb2_fop_read(struct file *file, char __user *buf, 497 size_t count, loff_t *ppos); 498 unsigned int vb2_fop_poll(struct file *file, poll_table *wait); 499 #ifndef CONFIG_MMU 500 unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr, 501 unsigned long len, unsigned long pgoff, unsigned long flags); 502 #endif 503 504 /* struct vb2_ops helpers, only use if vq->lock is non-NULL. */ 505 506 void vb2_ops_wait_prepare(struct vb2_queue *vq); 507 void vb2_ops_wait_finish(struct vb2_queue *vq); 508 509 #endif /* _MEDIA_VIDEOBUF2_CORE_H */ 510