1 /* 2 * videobuf2-core.h - Video Buffer 2 Core 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/dma-buf.h> 19 #include <linux/bitops.h> 20 #include <media/media-request.h> 21 #include <media/frame_vector.h> 22 23 #define VB2_MAX_FRAME (32) 24 #define VB2_MAX_PLANES (8) 25 26 /** 27 * enum vb2_memory - type of memory model used to make the buffers visible 28 * on userspace. 29 * 30 * @VB2_MEMORY_UNKNOWN: Buffer status is unknown or it is not used yet on 31 * userspace. 32 * @VB2_MEMORY_MMAP: The buffers are allocated by the Kernel and it is 33 * memory mapped via mmap() ioctl. This model is 34 * also used when the user is using the buffers via 35 * read() or write() system calls. 36 * @VB2_MEMORY_USERPTR: The buffers was allocated in userspace and it is 37 * memory mapped via mmap() ioctl. 38 * @VB2_MEMORY_DMABUF: The buffers are passed to userspace via DMA buffer. 39 */ 40 enum vb2_memory { 41 VB2_MEMORY_UNKNOWN = 0, 42 VB2_MEMORY_MMAP = 1, 43 VB2_MEMORY_USERPTR = 2, 44 VB2_MEMORY_DMABUF = 4, 45 }; 46 47 struct vb2_fileio_data; 48 struct vb2_threadio_data; 49 struct vb2_buffer; 50 51 /** 52 * struct vb2_mem_ops - memory handling/memory allocator operations. 53 * @alloc: allocate video memory and, optionally, allocator private data, 54 * return ERR_PTR() on failure or a pointer to allocator private, 55 * per-buffer data on success; the returned private structure 56 * will then be passed as @buf_priv argument to other ops in this 57 * structure. The size argument to this function shall be 58 * *page aligned*. 59 * @put: inform the allocator that the buffer will no longer be used; 60 * usually will result in the allocator freeing the buffer (if 61 * no other users of this buffer are present); the @buf_priv 62 * argument is the allocator private per-buffer structure 63 * previously returned from the alloc callback. 64 * @get_dmabuf: acquire userspace memory for a hardware operation; used for 65 * DMABUF memory types. 66 * @get_userptr: acquire userspace memory for a hardware operation; used for 67 * USERPTR memory types; vaddr is the address passed to the 68 * videobuf2 layer when queuing a video buffer of USERPTR type; 69 * should return an allocator private per-buffer structure 70 * associated with the buffer on success, ERR_PTR() on failure; 71 * the returned private structure will then be passed as @buf_priv 72 * argument to other ops in this structure. 73 * @put_userptr: inform the allocator that a USERPTR buffer will no longer 74 * be used. 75 * @prepare: called every time the buffer is passed from userspace to the 76 * driver, useful for cache synchronisation, optional. 77 * @finish: called every time the buffer is passed back from the driver 78 * to the userspace, also optional. 79 * @attach_dmabuf: attach a shared &struct dma_buf for a hardware operation; 80 * used for DMABUF memory types; dev is the alloc device 81 * dbuf is the shared dma_buf; returns ERR_PTR() on failure; 82 * allocator private per-buffer structure on success; 83 * this needs to be used for further accesses to the buffer. 84 * @detach_dmabuf: inform the exporter of the buffer that the current DMABUF 85 * buffer is no longer used; the @buf_priv argument is the 86 * allocator private per-buffer structure previously returned 87 * from the attach_dmabuf callback. 88 * @map_dmabuf: request for access to the dmabuf from allocator; the allocator 89 * of dmabuf is informed that this driver is going to use the 90 * dmabuf. 91 * @unmap_dmabuf: releases access control to the dmabuf - allocator is notified 92 * that this driver is done using the dmabuf for now. 93 * @vaddr: return a kernel virtual address to a given memory buffer 94 * associated with the passed private structure or NULL if no 95 * such mapping exists. 96 * @cookie: return allocator specific cookie for a given memory buffer 97 * associated with the passed private structure or NULL if not 98 * available. 99 * @num_users: return the current number of users of a memory buffer; 100 * return 1 if the videobuf2 layer (or actually the driver using 101 * it) is the only user. 102 * @mmap: setup a userspace mapping for a given memory buffer under 103 * the provided virtual memory region. 104 * 105 * Those operations are used by the videobuf2 core to implement the memory 106 * handling/memory allocators for each type of supported streaming I/O method. 107 * 108 * .. note:: 109 * #) Required ops for USERPTR types: get_userptr, put_userptr. 110 * 111 * #) Required ops for MMAP types: alloc, put, num_users, mmap. 112 * 113 * #) Required ops for read/write access types: alloc, put, num_users, vaddr. 114 * 115 * #) Required ops for DMABUF types: attach_dmabuf, detach_dmabuf, 116 * map_dmabuf, unmap_dmabuf. 117 */ 118 struct vb2_mem_ops { 119 void *(*alloc)(struct vb2_buffer *vb, 120 struct device *dev, 121 unsigned long size); 122 void (*put)(void *buf_priv); 123 struct dma_buf *(*get_dmabuf)(struct vb2_buffer *vb, 124 void *buf_priv, 125 unsigned long flags); 126 127 void *(*get_userptr)(struct vb2_buffer *vb, 128 struct device *dev, 129 unsigned long vaddr, 130 unsigned long size); 131 void (*put_userptr)(void *buf_priv); 132 133 void (*prepare)(void *buf_priv); 134 void (*finish)(void *buf_priv); 135 136 void *(*attach_dmabuf)(struct vb2_buffer *vb, 137 struct device *dev, 138 struct dma_buf *dbuf, 139 unsigned long size); 140 void (*detach_dmabuf)(void *buf_priv); 141 int (*map_dmabuf)(void *buf_priv); 142 void (*unmap_dmabuf)(void *buf_priv); 143 144 void *(*vaddr)(struct vb2_buffer *vb, void *buf_priv); 145 void *(*cookie)(struct vb2_buffer *vb, void *buf_priv); 146 147 unsigned int (*num_users)(void *buf_priv); 148 149 int (*mmap)(void *buf_priv, struct vm_area_struct *vma); 150 }; 151 152 /** 153 * struct vb2_plane - plane information. 154 * @mem_priv: private data with this plane. 155 * @dbuf: dma_buf - shared buffer object. 156 * @dbuf_mapped: flag to show whether dbuf is mapped or not 157 * @dbuf_duplicated: boolean to show whether dbuf is duplicated with a 158 * previous plane of the buffer. 159 * @bytesused: number of bytes occupied by data in the plane (payload). 160 * @length: size of this plane (NOT the payload) in bytes. The maximum 161 * valid size is MAX_UINT - PAGE_SIZE. 162 * @min_length: minimum required size of this plane (NOT the payload) in bytes. 163 * @length is always greater or equal to @min_length, and like 164 * @length, it is limited to MAX_UINT - PAGE_SIZE. 165 * @m: Union with memtype-specific data. 166 * @m.offset: when memory in the associated struct vb2_buffer is 167 * %VB2_MEMORY_MMAP, equals the offset from the start of 168 * the device memory for this plane (or is a "cookie" that 169 * should be passed to mmap() called on the video node). 170 * @m.userptr: when memory is %VB2_MEMORY_USERPTR, a userspace pointer 171 * pointing to this plane. 172 * @m.fd: when memory is %VB2_MEMORY_DMABUF, a userspace file 173 * descriptor associated with this plane. 174 * @data_offset: offset in the plane to the start of data; usually 0, 175 * unless there is a header in front of the data. 176 * 177 * Should contain enough information to be able to cover all the fields 178 * of &struct v4l2_plane at videodev2.h. 179 */ 180 struct vb2_plane { 181 void *mem_priv; 182 struct dma_buf *dbuf; 183 unsigned int dbuf_mapped; 184 bool dbuf_duplicated; 185 unsigned int bytesused; 186 unsigned int length; 187 unsigned int min_length; 188 union { 189 unsigned int offset; 190 unsigned long userptr; 191 int fd; 192 } m; 193 unsigned int data_offset; 194 }; 195 196 /** 197 * enum vb2_io_modes - queue access methods. 198 * @VB2_MMAP: driver supports MMAP with streaming API. 199 * @VB2_USERPTR: driver supports USERPTR with streaming API. 200 * @VB2_READ: driver supports read() style access. 201 * @VB2_WRITE: driver supports write() style access. 202 * @VB2_DMABUF: driver supports DMABUF with streaming API. 203 */ 204 enum vb2_io_modes { 205 VB2_MMAP = BIT(0), 206 VB2_USERPTR = BIT(1), 207 VB2_READ = BIT(2), 208 VB2_WRITE = BIT(3), 209 VB2_DMABUF = BIT(4), 210 }; 211 212 /** 213 * enum vb2_buffer_state - current video buffer state. 214 * @VB2_BUF_STATE_DEQUEUED: buffer under userspace control. 215 * @VB2_BUF_STATE_IN_REQUEST: buffer is queued in media request. 216 * @VB2_BUF_STATE_PREPARING: buffer is being prepared in videobuf2. 217 * @VB2_BUF_STATE_QUEUED: buffer queued in videobuf2, but not in driver. 218 * @VB2_BUF_STATE_ACTIVE: buffer queued in driver and possibly used 219 * in a hardware operation. 220 * @VB2_BUF_STATE_DONE: buffer returned from driver to videobuf2, but 221 * not yet dequeued to userspace. 222 * @VB2_BUF_STATE_ERROR: same as above, but the operation on the buffer 223 * has ended with an error, which will be reported 224 * to the userspace when it is dequeued. 225 */ 226 enum vb2_buffer_state { 227 VB2_BUF_STATE_DEQUEUED, 228 VB2_BUF_STATE_IN_REQUEST, 229 VB2_BUF_STATE_PREPARING, 230 VB2_BUF_STATE_QUEUED, 231 VB2_BUF_STATE_ACTIVE, 232 VB2_BUF_STATE_DONE, 233 VB2_BUF_STATE_ERROR, 234 }; 235 236 struct vb2_queue; 237 238 /** 239 * struct vb2_buffer - represents a video buffer. 240 * @vb2_queue: pointer to &struct vb2_queue with the queue to 241 * which this driver belongs. 242 * @index: id number of the buffer. 243 * @type: buffer type. 244 * @memory: the method, in which the actual data is passed. 245 * @num_planes: number of planes in the buffer 246 * on an internal driver queue. 247 * @timestamp: frame timestamp in ns. 248 * @request: the request this buffer is associated with. 249 * @req_obj: used to bind this buffer to a request. This 250 * request object has a refcount. 251 */ 252 struct vb2_buffer { 253 struct vb2_queue *vb2_queue; 254 unsigned int index; 255 unsigned int type; 256 unsigned int memory; 257 unsigned int num_planes; 258 u64 timestamp; 259 struct media_request *request; 260 struct media_request_object req_obj; 261 262 /* private: internal use only 263 * 264 * state: current buffer state; do not change 265 * synced: this buffer has been synced for DMA, i.e. the 266 * 'prepare' memop was called. It is cleared again 267 * after the 'finish' memop is called. 268 * prepared: this buffer has been prepared, i.e. the 269 * buf_prepare op was called. It is cleared again 270 * after the 'buf_finish' op is called. 271 * copied_timestamp: the timestamp of this capture buffer was copied 272 * from an output buffer. 273 * skip_cache_sync_on_prepare: when set buffer's ->prepare() function 274 * skips cache sync/invalidation. 275 * skip_cache_sync_on_finish: when set buffer's ->finish() function 276 * skips cache sync/invalidation. 277 * planes: per-plane information; do not change 278 * queued_entry: entry on the queued buffers list, which holds 279 * all buffers queued from userspace 280 * done_entry: entry on the list that stores all buffers ready 281 * to be dequeued to userspace 282 */ 283 enum vb2_buffer_state state; 284 unsigned int synced:1; 285 unsigned int prepared:1; 286 unsigned int copied_timestamp:1; 287 unsigned int skip_cache_sync_on_prepare:1; 288 unsigned int skip_cache_sync_on_finish:1; 289 290 struct vb2_plane planes[VB2_MAX_PLANES]; 291 struct list_head queued_entry; 292 struct list_head done_entry; 293 #ifdef CONFIG_VIDEO_ADV_DEBUG 294 /* 295 * Counters for how often these buffer-related ops are 296 * called. Used to check for unbalanced ops. 297 */ 298 u32 cnt_mem_alloc; 299 u32 cnt_mem_put; 300 u32 cnt_mem_get_dmabuf; 301 u32 cnt_mem_get_userptr; 302 u32 cnt_mem_put_userptr; 303 u32 cnt_mem_prepare; 304 u32 cnt_mem_finish; 305 u32 cnt_mem_attach_dmabuf; 306 u32 cnt_mem_detach_dmabuf; 307 u32 cnt_mem_map_dmabuf; 308 u32 cnt_mem_unmap_dmabuf; 309 u32 cnt_mem_vaddr; 310 u32 cnt_mem_cookie; 311 u32 cnt_mem_num_users; 312 u32 cnt_mem_mmap; 313 314 u32 cnt_buf_out_validate; 315 u32 cnt_buf_init; 316 u32 cnt_buf_prepare; 317 u32 cnt_buf_finish; 318 u32 cnt_buf_cleanup; 319 u32 cnt_buf_queue; 320 u32 cnt_buf_request_complete; 321 322 /* This counts the number of calls to vb2_buffer_done() */ 323 u32 cnt_buf_done; 324 #endif 325 }; 326 327 /** 328 * struct vb2_ops - driver-specific callbacks. 329 * 330 * These operations are not called from interrupt context except where 331 * mentioned specifically. 332 * 333 * @queue_setup: called from VIDIOC_REQBUFS() and VIDIOC_CREATE_BUFS() 334 * handlers before memory allocation. It can be called 335 * twice: if the original number of requested buffers 336 * could not be allocated, then it will be called a 337 * second time with the actually allocated number of 338 * buffers to verify if that is OK. 339 * The driver should return the required number of buffers 340 * in \*num_buffers, the required number of planes per 341 * buffer in \*num_planes, the size of each plane should be 342 * set in the sizes\[\] array and optional per-plane 343 * allocator specific device in the alloc_devs\[\] array. 344 * When called from VIDIOC_REQBUFS(), \*num_planes == 0, 345 * the driver has to use the currently configured format to 346 * determine the plane sizes and \*num_buffers is the total 347 * number of buffers that are being allocated. When called 348 * from VIDIOC_CREATE_BUFS(), \*num_planes != 0 and it 349 * describes the requested number of planes and sizes\[\] 350 * contains the requested plane sizes. In this case 351 * \*num_buffers are being allocated additionally to 352 * the buffers already allocated. If either \*num_planes 353 * or the requested sizes are invalid callback must return %-EINVAL. 354 * @wait_prepare: release any locks taken while calling vb2 functions; 355 * it is called before an ioctl needs to wait for a new 356 * buffer to arrive; required to avoid a deadlock in 357 * blocking access type. 358 * @wait_finish: reacquire all locks released in the previous callback; 359 * required to continue operation after sleeping while 360 * waiting for a new buffer to arrive. 361 * @buf_out_validate: called when the output buffer is prepared or queued 362 * to a request; drivers can use this to validate 363 * userspace-provided information; this is required only 364 * for OUTPUT queues. 365 * @buf_init: called once after allocating a buffer (in MMAP case) 366 * or after acquiring a new USERPTR buffer; drivers may 367 * perform additional buffer-related initialization; 368 * initialization failure (return != 0) will prevent 369 * queue setup from completing successfully; optional. 370 * @buf_prepare: called every time the buffer is queued from userspace 371 * and from the VIDIOC_PREPARE_BUF() ioctl; drivers may 372 * perform any initialization required before each 373 * hardware operation in this callback; drivers can 374 * access/modify the buffer here as it is still synced for 375 * the CPU; drivers that support VIDIOC_CREATE_BUFS() must 376 * also validate the buffer size; if an error is returned, 377 * the buffer will not be queued in driver; optional. 378 * @buf_finish: called before every dequeue of the buffer back to 379 * userspace; the buffer is synced for the CPU, so drivers 380 * can access/modify the buffer contents; drivers may 381 * perform any operations required before userspace 382 * accesses the buffer; optional. The buffer state can be 383 * one of the following: %DONE and %ERROR occur while 384 * streaming is in progress, and the %PREPARED state occurs 385 * when the queue has been canceled and all pending 386 * buffers are being returned to their default %DEQUEUED 387 * state. Typically you only have to do something if the 388 * state is %VB2_BUF_STATE_DONE, since in all other cases 389 * the buffer contents will be ignored anyway. 390 * @buf_cleanup: called once before the buffer is freed; drivers may 391 * perform any additional cleanup; optional. 392 * @prepare_streaming: called once to prepare for 'streaming' state; this is 393 * where validation can be done to verify everything is 394 * okay and streaming resources can be claimed. It is 395 * called when the VIDIOC_STREAMON ioctl is called. The 396 * actual streaming starts when @start_streaming is called. 397 * Optional. 398 * @start_streaming: called once to enter 'streaming' state; the driver may 399 * receive buffers with @buf_queue callback 400 * before @start_streaming is called; the driver gets the 401 * number of already queued buffers in count parameter; 402 * driver can return an error if hardware fails, in that 403 * case all buffers that have been already given by 404 * the @buf_queue callback are to be returned by the driver 405 * by calling vb2_buffer_done() with %VB2_BUF_STATE_QUEUED. 406 * If you need a minimum number of buffers before you can 407 * start streaming, then set 408 * &vb2_queue->min_queued_buffers. If that is non-zero 409 * then @start_streaming won't be called until at least 410 * that many buffers have been queued up by userspace. 411 * @stop_streaming: called when 'streaming' state must be disabled; driver 412 * should stop any DMA transactions or wait until they 413 * finish and give back all buffers it got from &buf_queue 414 * callback by calling vb2_buffer_done() with either 415 * %VB2_BUF_STATE_DONE or %VB2_BUF_STATE_ERROR; may use 416 * vb2_wait_for_all_buffers() function 417 * @unprepare_streaming:called as counterpart to @prepare_streaming; any claimed 418 * streaming resources can be released here. It is 419 * called when the VIDIOC_STREAMOFF ioctls is called or 420 * when the streaming filehandle is closed. Optional. 421 * @buf_queue: passes buffer vb to the driver; driver may start 422 * hardware operation on this buffer; driver should give 423 * the buffer back by calling vb2_buffer_done() function; 424 * it is always called after calling VIDIOC_STREAMON() 425 * ioctl; might be called before @start_streaming callback 426 * if user pre-queued buffers before calling 427 * VIDIOC_STREAMON(). 428 * @buf_request_complete: a buffer that was never queued to the driver but is 429 * associated with a queued request was canceled. 430 * The driver will have to mark associated objects in the 431 * request as completed; required if requests are 432 * supported. 433 */ 434 struct vb2_ops { 435 int (*queue_setup)(struct vb2_queue *q, 436 unsigned int *num_buffers, unsigned int *num_planes, 437 unsigned int sizes[], struct device *alloc_devs[]); 438 439 void (*wait_prepare)(struct vb2_queue *q); 440 void (*wait_finish)(struct vb2_queue *q); 441 442 int (*buf_out_validate)(struct vb2_buffer *vb); 443 int (*buf_init)(struct vb2_buffer *vb); 444 int (*buf_prepare)(struct vb2_buffer *vb); 445 void (*buf_finish)(struct vb2_buffer *vb); 446 void (*buf_cleanup)(struct vb2_buffer *vb); 447 448 int (*prepare_streaming)(struct vb2_queue *q); 449 int (*start_streaming)(struct vb2_queue *q, unsigned int count); 450 void (*stop_streaming)(struct vb2_queue *q); 451 void (*unprepare_streaming)(struct vb2_queue *q); 452 453 void (*buf_queue)(struct vb2_buffer *vb); 454 455 void (*buf_request_complete)(struct vb2_buffer *vb); 456 }; 457 458 /** 459 * struct vb2_buf_ops - driver-specific callbacks. 460 * 461 * @verify_planes_array: Verify that a given user space structure contains 462 * enough planes for the buffer. This is called 463 * for each dequeued buffer. 464 * @init_buffer: given a &vb2_buffer initialize the extra data after 465 * struct vb2_buffer. 466 * For V4L2 this is a &struct vb2_v4l2_buffer. 467 * @fill_user_buffer: given a &vb2_buffer fill in the userspace structure. 468 * For V4L2 this is a &struct v4l2_buffer. 469 * @fill_vb2_buffer: given a userspace structure, fill in the &vb2_buffer. 470 * If the userspace structure is invalid, then this op 471 * will return an error. 472 * @copy_timestamp: copy the timestamp from a userspace structure to 473 * the &struct vb2_buffer. 474 */ 475 struct vb2_buf_ops { 476 int (*verify_planes_array)(struct vb2_buffer *vb, const void *pb); 477 void (*init_buffer)(struct vb2_buffer *vb); 478 void (*fill_user_buffer)(struct vb2_buffer *vb, void *pb); 479 int (*fill_vb2_buffer)(struct vb2_buffer *vb, struct vb2_plane *planes); 480 void (*copy_timestamp)(struct vb2_buffer *vb, const void *pb); 481 }; 482 483 /** 484 * struct vb2_queue - a videobuf2 queue. 485 * 486 * @type: private buffer type whose content is defined by the vb2-core 487 * caller. For example, for V4L2, it should match 488 * the types defined on &enum v4l2_buf_type. 489 * @io_modes: supported io methods (see &enum vb2_io_modes). 490 * @dev: device to use for the default allocation context if the driver 491 * doesn't fill in the @alloc_devs array. 492 * @dma_attrs: DMA attributes to use for the DMA. 493 * @bidirectional: when this flag is set the DMA direction for the buffers of 494 * this queue will be overridden with %DMA_BIDIRECTIONAL direction. 495 * This is useful in cases where the hardware (firmware) writes to 496 * a buffer which is mapped as read (%DMA_TO_DEVICE), or reads from 497 * buffer which is mapped for write (%DMA_FROM_DEVICE) in order 498 * to satisfy some internal hardware restrictions or adds a padding 499 * needed by the processing algorithm. In case the DMA mapping is 500 * not bidirectional but the hardware (firmware) trying to access 501 * the buffer (in the opposite direction) this could lead to an 502 * IOMMU protection faults. 503 * @fileio_read_once: report EOF after reading the first buffer 504 * @fileio_write_immediately: queue buffer after each write() call 505 * @allow_zero_bytesused: allow bytesused == 0 to be passed to the driver 506 * @quirk_poll_must_check_waiting_for_buffers: Return %EPOLLERR at poll when QBUF 507 * has not been called. This is a vb1 idiom that has been adopted 508 * also by vb2. 509 * @supports_requests: this queue supports the Request API. 510 * @requires_requests: this queue requires the Request API. If this is set to 1, 511 * then supports_requests must be set to 1 as well. 512 * @uses_qbuf: qbuf was used directly for this queue. Set to 1 the first 513 * time this is called. Set to 0 when the queue is canceled. 514 * If this is 1, then you cannot queue buffers from a request. 515 * @uses_requests: requests are used for this queue. Set to 1 the first time 516 * a request is queued. Set to 0 when the queue is canceled. 517 * If this is 1, then you cannot queue buffers directly. 518 * @allow_cache_hints: when set user-space can pass cache management hints in 519 * order to skip cache flush/invalidation on ->prepare() or/and 520 * ->finish(). 521 * @non_coherent_mem: when set queue will attempt to allocate buffers using 522 * non-coherent memory. 523 * @lock: pointer to a mutex that protects the &struct vb2_queue. The 524 * driver can set this to a mutex to let the v4l2 core serialize 525 * the queuing ioctls. If the driver wants to handle locking 526 * itself, then this should be set to NULL. This lock is not used 527 * by the videobuf2 core API. 528 * @owner: The filehandle that 'owns' the buffers, i.e. the filehandle 529 * that called reqbufs, create_buffers or started fileio. 530 * This field is not used by the videobuf2 core API, but it allows 531 * drivers to easily associate an owner filehandle with the queue. 532 * @ops: driver-specific callbacks 533 * @mem_ops: memory allocator specific callbacks 534 * @buf_ops: callbacks to deliver buffer information. 535 * between user-space and kernel-space. 536 * @drv_priv: driver private data. 537 * @subsystem_flags: Flags specific to the subsystem (V4L2/DVB/etc.). Not used 538 * by the vb2 core. 539 * @buf_struct_size: size of the driver-specific buffer structure; 540 * "0" indicates the driver doesn't want to use a custom buffer 541 * structure type. In that case a subsystem-specific struct 542 * will be used (in the case of V4L2 that is 543 * ``sizeof(struct vb2_v4l2_buffer)``). The first field of the 544 * driver-specific buffer structure must be the subsystem-specific 545 * struct (vb2_v4l2_buffer in the case of V4L2). 546 * @timestamp_flags: Timestamp flags; ``V4L2_BUF_FLAG_TIMESTAMP_*`` and 547 * ``V4L2_BUF_FLAG_TSTAMP_SRC_*`` 548 * @gfp_flags: additional gfp flags used when allocating the buffers. 549 * Typically this is 0, but it may be e.g. %GFP_DMA or %__GFP_DMA32 550 * to force the buffer allocation to a specific memory zone. 551 * @min_queued_buffers: the minimum number of queued buffers needed before 552 * @start_streaming can be called. Used when a DMA engine 553 * cannot be started unless at least this number of buffers 554 * have been queued into the driver. 555 * VIDIOC_REQBUFS will ensure at least @min_queued_buffers + 1 556 * buffers will be allocated. Note that VIDIOC_CREATE_BUFS will not 557 * modify the requested buffer count. 558 * @min_reqbufs_allocation: the minimum number of buffers to be allocated when 559 * calling VIDIOC_REQBUFS. Note that VIDIOC_CREATE_BUFS will *not* 560 * modify the requested buffer count and does not use this field. 561 * Drivers can set this if there has to be a certain number of 562 * buffers available for the hardware to work effectively. 563 * This allows calling VIDIOC_REQBUFS with a buffer count of 1 and 564 * it will be automatically adjusted to a workable buffer count. 565 * If set, then @min_reqbufs_allocation must be larger than 566 * @min_queued_buffers + 1. 567 * If this field is > 3, then it is highly recommended that the 568 * driver implements the V4L2_CID_MIN_BUFFERS_FOR_CAPTURE/OUTPUT 569 * control. 570 * @alloc_devs: &struct device memory type/allocator-specific per-plane device 571 */ 572 /* 573 * Private elements (won't appear at the uAPI book): 574 * @mmap_lock: private mutex used when buffers are allocated/freed/mmapped 575 * @memory: current memory type used 576 * @dma_dir: DMA mapping direction. 577 * @bufs: videobuf2 buffer structures. If it is non-NULL then 578 * bufs_bitmap is also non-NULL. 579 * @bufs_bitmap: bitmap tracking whether each bufs[] entry is used 580 * @max_num_buffers: upper limit of number of allocated/used buffers. 581 * If set to 0 v4l2 core will change it VB2_MAX_FRAME 582 * for backward compatibility. 583 * @queued_list: list of buffers currently queued from userspace 584 * @queued_count: number of buffers queued and ready for streaming. 585 * @owned_by_drv_count: number of buffers owned by the driver 586 * @done_list: list of buffers ready to be dequeued to userspace 587 * @done_lock: lock to protect done_list list 588 * @done_wq: waitqueue for processes waiting for buffers ready to be dequeued 589 * @streaming: current streaming state 590 * @start_streaming_called: @start_streaming was called successfully and we 591 * started streaming. 592 * @error: a fatal error occurred on the queue 593 * @waiting_for_buffers: used in poll() to check if vb2 is still waiting for 594 * buffers. Only set for capture queues if qbuf has not yet been 595 * called since poll() needs to return %EPOLLERR in that situation. 596 * @waiting_in_dqbuf: set by the core for the duration of a blocking DQBUF, when 597 * it has to wait for a buffer to become available with vb2_queue->lock 598 * released. Used to prevent destroying the queue by other threads. 599 * @is_multiplanar: set if buffer type is multiplanar 600 * @is_output: set if buffer type is output 601 * @is_busy: set if at least one buffer has been allocated at some time. 602 * @copy_timestamp: set if vb2-core should set timestamps 603 * @last_buffer_dequeued: used in poll() and DQBUF to immediately return if the 604 * last decoded buffer was already dequeued. Set for capture queues 605 * when a buffer with the %V4L2_BUF_FLAG_LAST is dequeued. 606 * @fileio: file io emulator internal data, used only if emulator is active 607 * @threadio: thread io internal data, used only if thread is active 608 * @name: queue name, used for logging purpose. Initialized automatically 609 * if left empty by drivers. 610 */ 611 struct vb2_queue { 612 unsigned int type; 613 unsigned int io_modes; 614 struct device *dev; 615 unsigned long dma_attrs; 616 unsigned int bidirectional:1; 617 unsigned int fileio_read_once:1; 618 unsigned int fileio_write_immediately:1; 619 unsigned int allow_zero_bytesused:1; 620 unsigned int quirk_poll_must_check_waiting_for_buffers:1; 621 unsigned int supports_requests:1; 622 unsigned int requires_requests:1; 623 unsigned int uses_qbuf:1; 624 unsigned int uses_requests:1; 625 unsigned int allow_cache_hints:1; 626 unsigned int non_coherent_mem:1; 627 628 struct mutex *lock; 629 void *owner; 630 631 const struct vb2_ops *ops; 632 const struct vb2_mem_ops *mem_ops; 633 const struct vb2_buf_ops *buf_ops; 634 635 void *drv_priv; 636 u32 subsystem_flags; 637 unsigned int buf_struct_size; 638 u32 timestamp_flags; 639 gfp_t gfp_flags; 640 u32 min_queued_buffers; 641 u32 min_reqbufs_allocation; 642 643 struct device *alloc_devs[VB2_MAX_PLANES]; 644 645 /* private: internal use only */ 646 struct mutex mmap_lock; 647 unsigned int memory; 648 enum dma_data_direction dma_dir; 649 struct vb2_buffer **bufs; 650 unsigned long *bufs_bitmap; 651 unsigned int max_num_buffers; 652 653 struct list_head queued_list; 654 unsigned int queued_count; 655 656 atomic_t owned_by_drv_count; 657 struct list_head done_list; 658 spinlock_t done_lock; 659 wait_queue_head_t done_wq; 660 661 unsigned int streaming:1; 662 unsigned int start_streaming_called:1; 663 unsigned int error:1; 664 unsigned int waiting_for_buffers:1; 665 unsigned int waiting_in_dqbuf:1; 666 unsigned int is_multiplanar:1; 667 unsigned int is_output:1; 668 unsigned int is_busy:1; 669 unsigned int copy_timestamp:1; 670 unsigned int last_buffer_dequeued:1; 671 672 struct vb2_fileio_data *fileio; 673 struct vb2_threadio_data *threadio; 674 675 char name[32]; 676 677 #ifdef CONFIG_VIDEO_ADV_DEBUG 678 /* 679 * Counters for how often these queue-related ops are 680 * called. Used to check for unbalanced ops. 681 */ 682 u32 cnt_queue_setup; 683 u32 cnt_wait_prepare; 684 u32 cnt_wait_finish; 685 u32 cnt_prepare_streaming; 686 u32 cnt_start_streaming; 687 u32 cnt_stop_streaming; 688 u32 cnt_unprepare_streaming; 689 #endif 690 }; 691 692 /** 693 * vb2_queue_allows_cache_hints() - Return true if the queue allows cache 694 * and memory consistency hints. 695 * 696 * @q: pointer to &struct vb2_queue with videobuf2 queue 697 */ 698 static inline bool vb2_queue_allows_cache_hints(struct vb2_queue *q) 699 { 700 return q->allow_cache_hints && q->memory == VB2_MEMORY_MMAP; 701 } 702 703 /** 704 * vb2_plane_vaddr() - Return a kernel virtual address of a given plane. 705 * @vb: pointer to &struct vb2_buffer to which the plane in 706 * question belongs to. 707 * @plane_no: plane number for which the address is to be returned. 708 * 709 * This function returns a kernel virtual address of a given plane if 710 * such a mapping exist, NULL otherwise. 711 */ 712 void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no); 713 714 /** 715 * vb2_plane_cookie() - Return allocator specific cookie for the given plane. 716 * @vb: pointer to &struct vb2_buffer to which the plane in 717 * question belongs to. 718 * @plane_no: plane number for which the cookie is to be returned. 719 * 720 * This function returns an allocator specific cookie for a given plane if 721 * available, NULL otherwise. The allocator should provide some simple static 722 * inline function, which would convert this cookie to the allocator specific 723 * type that can be used directly by the driver to access the buffer. This can 724 * be for example physical address, pointer to scatter list or IOMMU mapping. 725 */ 726 void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no); 727 728 /** 729 * vb2_buffer_done() - inform videobuf2 that an operation on a buffer 730 * is finished. 731 * @vb: pointer to &struct vb2_buffer to be used. 732 * @state: state of the buffer, as defined by &enum vb2_buffer_state. 733 * Either %VB2_BUF_STATE_DONE if the operation finished 734 * successfully, %VB2_BUF_STATE_ERROR if the operation finished 735 * with an error or %VB2_BUF_STATE_QUEUED. 736 * 737 * This function should be called by the driver after a hardware operation on 738 * a buffer is finished and the buffer may be returned to userspace. The driver 739 * cannot use this buffer anymore until it is queued back to it by videobuf 740 * by the means of &vb2_ops->buf_queue callback. Only buffers previously queued 741 * to the driver by &vb2_ops->buf_queue can be passed to this function. 742 * 743 * While streaming a buffer can only be returned in state DONE or ERROR. 744 * The &vb2_ops->start_streaming op can also return them in case the DMA engine 745 * cannot be started for some reason. In that case the buffers should be 746 * returned with state QUEUED to put them back into the queue. 747 */ 748 void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state); 749 750 /** 751 * vb2_discard_done() - discard all buffers marked as DONE. 752 * @q: pointer to &struct vb2_queue with videobuf2 queue. 753 * 754 * This function is intended to be used with suspend/resume operations. It 755 * discards all 'done' buffers as they would be too old to be requested after 756 * resume. 757 * 758 * Drivers must stop the hardware and synchronize with interrupt handlers and/or 759 * delayed works before calling this function to make sure no buffer will be 760 * touched by the driver and/or hardware. 761 */ 762 void vb2_discard_done(struct vb2_queue *q); 763 764 /** 765 * vb2_wait_for_all_buffers() - wait until all buffers are given back to vb2. 766 * @q: pointer to &struct vb2_queue with videobuf2 queue. 767 * 768 * This function will wait until all buffers that have been given to the driver 769 * by &vb2_ops->buf_queue are given back to vb2 with vb2_buffer_done(). It 770 * doesn't call &vb2_ops->wait_prepare/&vb2_ops->wait_finish pair. 771 * It is intended to be called with all locks taken, for example from 772 * &vb2_ops->stop_streaming callback. 773 */ 774 int vb2_wait_for_all_buffers(struct vb2_queue *q); 775 776 /** 777 * vb2_core_querybuf() - query video buffer information. 778 * @q: pointer to &struct vb2_queue with videobuf2 queue. 779 * @vb: pointer to struct &vb2_buffer. 780 * @pb: buffer struct passed from userspace. 781 * 782 * Videobuf2 core helper to implement VIDIOC_QUERYBUF() operation. It is called 783 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``. 784 * 785 * The passed buffer should have been verified. 786 * 787 * This function fills the relevant information for the userspace. 788 * 789 * Return: returns zero on success; an error code otherwise. 790 */ 791 void vb2_core_querybuf(struct vb2_queue *q, struct vb2_buffer *vb, void *pb); 792 793 /** 794 * vb2_core_reqbufs() - Initiate streaming. 795 * @q: pointer to &struct vb2_queue with videobuf2 queue. 796 * @memory: memory type, as defined by &enum vb2_memory. 797 * @flags: auxiliary queue/buffer management flags. Currently, the only 798 * used flag is %V4L2_MEMORY_FLAG_NON_COHERENT. 799 * @count: requested buffer count. 800 * 801 * Videobuf2 core helper to implement VIDIOC_REQBUF() operation. It is called 802 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``. 803 * 804 * This function: 805 * 806 * #) verifies streaming parameters passed from the userspace; 807 * #) sets up the queue; 808 * #) negotiates number of buffers and planes per buffer with the driver 809 * to be used during streaming; 810 * #) allocates internal buffer structures (&struct vb2_buffer), according to 811 * the agreed parameters; 812 * #) for MMAP memory type, allocates actual video memory, using the 813 * memory handling/allocation routines provided during queue initialization. 814 * 815 * If req->count is 0, all the memory will be freed instead. 816 * 817 * If the queue has been allocated previously by a previous vb2_core_reqbufs() 818 * call and the queue is not busy, memory will be reallocated. 819 * 820 * Return: returns zero on success; an error code otherwise. 821 */ 822 int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory, 823 unsigned int flags, unsigned int *count); 824 825 /** 826 * vb2_core_create_bufs() - Allocate buffers and any required auxiliary structs 827 * @q: pointer to &struct vb2_queue with videobuf2 queue. 828 * @memory: memory type, as defined by &enum vb2_memory. 829 * @flags: auxiliary queue/buffer management flags. 830 * @count: requested buffer count. 831 * @requested_planes: number of planes requested. 832 * @requested_sizes: array with the size of the planes. 833 * @first_index: index of the first created buffer, all allocated buffers have 834 * indices in the range [first_index..first_index+count-1] 835 * 836 * Videobuf2 core helper to implement VIDIOC_CREATE_BUFS() operation. It is 837 * called internally by VB2 by an API-specific handler, like 838 * ``videobuf2-v4l2.h``. 839 * 840 * This function: 841 * 842 * #) verifies parameter sanity; 843 * #) calls the &vb2_ops->queue_setup queue operation; 844 * #) performs any necessary memory allocations. 845 * 846 * Return: returns zero on success; an error code otherwise. 847 */ 848 int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory, 849 unsigned int flags, unsigned int *count, 850 unsigned int requested_planes, 851 const unsigned int requested_sizes[], 852 unsigned int *first_index); 853 854 /** 855 * vb2_core_prepare_buf() - Pass ownership of a buffer from userspace 856 * to the kernel. 857 * @q: pointer to &struct vb2_queue with videobuf2 queue. 858 * @vb: pointer to struct &vb2_buffer. 859 * @pb: buffer structure passed from userspace to 860 * &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver. 861 * 862 * Videobuf2 core helper to implement VIDIOC_PREPARE_BUF() operation. It is 863 * called internally by VB2 by an API-specific handler, like 864 * ``videobuf2-v4l2.h``. 865 * 866 * The passed buffer should have been verified. 867 * 868 * This function calls vb2_ops->buf_prepare callback in the driver 869 * (if provided), in which driver-specific buffer initialization can 870 * be performed. 871 * 872 * Return: returns zero on success; an error code otherwise. 873 */ 874 int vb2_core_prepare_buf(struct vb2_queue *q, struct vb2_buffer *vb, void *pb); 875 876 /** 877 * vb2_core_remove_bufs() - 878 * @q: pointer to &struct vb2_queue with videobuf2 queue. 879 * @start: first index of the range of buffers to remove. 880 * @count: number of buffers to remove. 881 * 882 * Return: returns zero on success; an error code otherwise. 883 */ 884 int vb2_core_remove_bufs(struct vb2_queue *q, unsigned int start, unsigned int count); 885 886 /** 887 * vb2_core_qbuf() - Queue a buffer from userspace 888 * 889 * @q: pointer to &struct vb2_queue with videobuf2 queue. 890 * @vb: pointer to struct &vb2_buffer. 891 * @pb: buffer structure passed from userspace to 892 * v4l2_ioctl_ops->vidioc_qbuf handler in driver 893 * @req: pointer to &struct media_request, may be NULL. 894 * 895 * Videobuf2 core helper to implement VIDIOC_QBUF() operation. It is called 896 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``. 897 * 898 * This function: 899 * 900 * #) If @req is non-NULL, then the buffer will be bound to this 901 * media request and it returns. The buffer will be prepared and 902 * queued to the driver (i.e. the next two steps) when the request 903 * itself is queued. 904 * #) if necessary, calls &vb2_ops->buf_prepare callback in the driver 905 * (if provided), in which driver-specific buffer initialization can 906 * be performed; 907 * #) if streaming is on, queues the buffer in driver by the means of 908 * &vb2_ops->buf_queue callback for processing. 909 * 910 * Return: returns zero on success; an error code otherwise. 911 */ 912 int vb2_core_qbuf(struct vb2_queue *q, struct vb2_buffer *vb, void *pb, 913 struct media_request *req); 914 915 /** 916 * vb2_core_dqbuf() - Dequeue a buffer to the userspace 917 * @q: pointer to &struct vb2_queue with videobuf2 queue 918 * @pindex: pointer to the buffer index. May be NULL 919 * @pb: buffer structure passed from userspace to 920 * v4l2_ioctl_ops->vidioc_dqbuf handler in driver. 921 * @nonblocking: if true, this call will not sleep waiting for a buffer if no 922 * buffers ready for dequeuing are present. Normally the driver 923 * would be passing (file->f_flags & O_NONBLOCK) here. 924 * 925 * Videobuf2 core helper to implement VIDIOC_DQBUF() operation. It is called 926 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``. 927 * 928 * This function: 929 * 930 * #) calls buf_finish callback in the driver (if provided), in which 931 * driver can perform any additional operations that may be required before 932 * returning the buffer to userspace, such as cache sync, 933 * #) the buffer struct members are filled with relevant information for 934 * the userspace. 935 * 936 * Return: returns zero on success; an error code otherwise. 937 */ 938 int vb2_core_dqbuf(struct vb2_queue *q, unsigned int *pindex, void *pb, 939 bool nonblocking); 940 941 /** 942 * vb2_core_streamon() - Implements VB2 stream ON logic 943 * 944 * @q: pointer to &struct vb2_queue with videobuf2 queue 945 * @type: type of the queue to be started. 946 * For V4L2, this is defined by &enum v4l2_buf_type type. 947 * 948 * Videobuf2 core helper to implement VIDIOC_STREAMON() operation. It is called 949 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``. 950 * 951 * Return: returns zero on success; an error code otherwise. 952 */ 953 int vb2_core_streamon(struct vb2_queue *q, unsigned int type); 954 955 /** 956 * vb2_core_streamoff() - Implements VB2 stream OFF logic 957 * 958 * @q: pointer to &struct vb2_queue with videobuf2 queue 959 * @type: type of the queue to be started. 960 * For V4L2, this is defined by &enum v4l2_buf_type type. 961 * 962 * Videobuf2 core helper to implement VIDIOC_STREAMOFF() operation. It is 963 * called internally by VB2 by an API-specific handler, like 964 * ``videobuf2-v4l2.h``. 965 * 966 * Return: returns zero on success; an error code otherwise. 967 */ 968 int vb2_core_streamoff(struct vb2_queue *q, unsigned int type); 969 970 /** 971 * vb2_core_expbuf() - Export a buffer as a file descriptor. 972 * @q: pointer to &struct vb2_queue with videobuf2 queue. 973 * @fd: pointer to the file descriptor associated with DMABUF 974 * (set by driver). 975 * @type: buffer type. 976 * @vb: pointer to struct &vb2_buffer. 977 * @plane: index of the plane to be exported, 0 for single plane queues 978 * @flags: file flags for newly created file, as defined at 979 * include/uapi/asm-generic/fcntl.h. 980 * Currently, the only used flag is %O_CLOEXEC. 981 * is supported, refer to manual of open syscall for more details. 982 * 983 * 984 * Videobuf2 core helper to implement VIDIOC_EXPBUF() operation. It is called 985 * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``. 986 * 987 * Return: returns zero on success; an error code otherwise. 988 */ 989 int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type, 990 struct vb2_buffer *vb, unsigned int plane, unsigned int flags); 991 992 /** 993 * vb2_core_queue_init() - initialize a videobuf2 queue 994 * @q: pointer to &struct vb2_queue with videobuf2 queue. 995 * This structure should be allocated in driver 996 * 997 * The &vb2_queue structure should be allocated by the driver. The driver is 998 * responsible of clearing it's content and setting initial values for some 999 * required entries before calling this function. 1000 * 1001 * .. note:: 1002 * 1003 * The following fields at @q should be set before calling this function: 1004 * &vb2_queue->ops, &vb2_queue->mem_ops, &vb2_queue->type. 1005 */ 1006 int vb2_core_queue_init(struct vb2_queue *q); 1007 1008 /** 1009 * vb2_core_queue_release() - stop streaming, release the queue and free memory 1010 * @q: pointer to &struct vb2_queue with videobuf2 queue. 1011 * 1012 * This function stops streaming and performs necessary clean ups, including 1013 * freeing video buffer memory. The driver is responsible for freeing 1014 * the &struct vb2_queue itself. 1015 */ 1016 void vb2_core_queue_release(struct vb2_queue *q); 1017 1018 /** 1019 * vb2_queue_error() - signal a fatal error on the queue 1020 * @q: pointer to &struct vb2_queue with videobuf2 queue. 1021 * 1022 * Flag that a fatal unrecoverable error has occurred and wake up all processes 1023 * waiting on the queue. Polling will now set %EPOLLERR and queuing and dequeuing 1024 * buffers will return %-EIO. 1025 * 1026 * The error flag will be cleared when canceling the queue, either from 1027 * vb2_streamoff() or vb2_queue_release(). Drivers should thus not call this 1028 * function before starting the stream, otherwise the error flag will remain set 1029 * until the queue is released when closing the device node. 1030 */ 1031 void vb2_queue_error(struct vb2_queue *q); 1032 1033 /** 1034 * vb2_mmap() - map video buffers into application address space. 1035 * @q: pointer to &struct vb2_queue with videobuf2 queue. 1036 * @vma: pointer to &struct vm_area_struct with the vma passed 1037 * to the mmap file operation handler in the driver. 1038 * 1039 * Should be called from mmap file operation handler of a driver. 1040 * This function maps one plane of one of the available video buffers to 1041 * userspace. To map whole video memory allocated on reqbufs, this function 1042 * has to be called once per each plane per each buffer previously allocated. 1043 * 1044 * When the userspace application calls mmap, it passes to it an offset returned 1045 * to it earlier by the means of &v4l2_ioctl_ops->vidioc_querybuf handler. 1046 * That offset acts as a "cookie", which is then used to identify the plane 1047 * to be mapped. 1048 * 1049 * This function finds a plane with a matching offset and a mapping is performed 1050 * by the means of a provided memory operation. 1051 * 1052 * The return values from this function are intended to be directly returned 1053 * from the mmap handler in driver. 1054 */ 1055 int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma); 1056 1057 #ifndef CONFIG_MMU 1058 /** 1059 * vb2_get_unmapped_area - map video buffers into application address space. 1060 * @q: pointer to &struct vb2_queue with videobuf2 queue. 1061 * @addr: memory address. 1062 * @len: buffer size. 1063 * @pgoff: page offset. 1064 * @flags: memory flags. 1065 * 1066 * This function is used in noMMU platforms to propose address mapping 1067 * for a given buffer. It's intended to be used as a handler for the 1068 * &file_operations->get_unmapped_area operation. 1069 * 1070 * This is called by the mmap() syscall routines will call this 1071 * to get a proposed address for the mapping, when ``!CONFIG_MMU``. 1072 */ 1073 unsigned long vb2_get_unmapped_area(struct vb2_queue *q, 1074 unsigned long addr, 1075 unsigned long len, 1076 unsigned long pgoff, 1077 unsigned long flags); 1078 #endif 1079 1080 /** 1081 * vb2_core_poll() - implements poll syscall() logic. 1082 * @q: pointer to &struct vb2_queue with videobuf2 queue. 1083 * @file: &struct file argument passed to the poll 1084 * file operation handler. 1085 * @wait: &poll_table wait argument passed to the poll 1086 * file operation handler. 1087 * 1088 * This function implements poll file operation handler for a driver. 1089 * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will 1090 * be informed that the file descriptor of a video device is available for 1091 * reading. 1092 * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor 1093 * will be reported as available for writing. 1094 * 1095 * The return values from this function are intended to be directly returned 1096 * from poll handler in driver. 1097 */ 1098 __poll_t vb2_core_poll(struct vb2_queue *q, struct file *file, 1099 poll_table *wait); 1100 1101 /** 1102 * vb2_read() - implements read() syscall logic. 1103 * @q: pointer to &struct vb2_queue with videobuf2 queue. 1104 * @data: pointed to target userspace buffer 1105 * @count: number of bytes to read 1106 * @ppos: file handle position tracking pointer 1107 * @nonblock: mode selector (1 means blocking calls, 0 means nonblocking) 1108 */ 1109 size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count, 1110 loff_t *ppos, int nonblock); 1111 /** 1112 * vb2_write() - implements write() syscall logic. 1113 * @q: pointer to &struct vb2_queue with videobuf2 queue. 1114 * @data: pointed to target userspace buffer 1115 * @count: number of bytes to write 1116 * @ppos: file handle position tracking pointer 1117 * @nonblock: mode selector (1 means blocking calls, 0 means nonblocking) 1118 */ 1119 size_t vb2_write(struct vb2_queue *q, const char __user *data, size_t count, 1120 loff_t *ppos, int nonblock); 1121 1122 /** 1123 * typedef vb2_thread_fnc - callback function for use with vb2_thread. 1124 * 1125 * @vb: pointer to struct &vb2_buffer. 1126 * @priv: pointer to a private data. 1127 * 1128 * This is called whenever a buffer is dequeued in the thread. 1129 */ 1130 typedef int (*vb2_thread_fnc)(struct vb2_buffer *vb, void *priv); 1131 1132 /** 1133 * vb2_thread_start() - start a thread for the given queue. 1134 * @q: pointer to &struct vb2_queue with videobuf2 queue. 1135 * @fnc: &vb2_thread_fnc callback function. 1136 * @priv: priv pointer passed to the callback function. 1137 * @thread_name:the name of the thread. This will be prefixed with "vb2-". 1138 * 1139 * This starts a thread that will queue and dequeue until an error occurs 1140 * or vb2_thread_stop() is called. 1141 * 1142 * .. attention:: 1143 * 1144 * This function should not be used for anything else but the videobuf2-dvb 1145 * support. If you think you have another good use-case for this, then please 1146 * contact the linux-media mailing list first. 1147 */ 1148 int vb2_thread_start(struct vb2_queue *q, vb2_thread_fnc fnc, void *priv, 1149 const char *thread_name); 1150 1151 /** 1152 * vb2_thread_stop() - stop the thread for the given queue. 1153 * @q: pointer to &struct vb2_queue with videobuf2 queue. 1154 */ 1155 int vb2_thread_stop(struct vb2_queue *q); 1156 1157 /** 1158 * vb2_is_streaming() - return streaming status of the queue. 1159 * @q: pointer to &struct vb2_queue with videobuf2 queue. 1160 */ 1161 static inline bool vb2_is_streaming(struct vb2_queue *q) 1162 { 1163 return q->streaming; 1164 } 1165 1166 /** 1167 * vb2_fileio_is_active() - return true if fileio is active. 1168 * @q: pointer to &struct vb2_queue with videobuf2 queue. 1169 * 1170 * This returns true if read() or write() is used to stream the data 1171 * as opposed to stream I/O. This is almost never an important distinction, 1172 * except in rare cases. One such case is that using read() or write() to 1173 * stream a format using %V4L2_FIELD_ALTERNATE is not allowed since there 1174 * is no way you can pass the field information of each buffer to/from 1175 * userspace. A driver that supports this field format should check for 1176 * this in the &vb2_ops->queue_setup op and reject it if this function returns 1177 * true. 1178 */ 1179 static inline bool vb2_fileio_is_active(struct vb2_queue *q) 1180 { 1181 return q->fileio; 1182 } 1183 1184 /** 1185 * vb2_get_num_buffers() - get the number of buffer in a queue 1186 * @q: pointer to &struct vb2_queue with videobuf2 queue. 1187 */ 1188 static inline unsigned int vb2_get_num_buffers(struct vb2_queue *q) 1189 { 1190 if (q->bufs_bitmap) 1191 return bitmap_weight(q->bufs_bitmap, q->max_num_buffers); 1192 1193 return 0; 1194 } 1195 1196 /** 1197 * vb2_is_busy() - return busy status of the queue. 1198 * @q: pointer to &struct vb2_queue with videobuf2 queue. 1199 * 1200 * This function checks if queue has any buffers allocated. 1201 */ 1202 static inline bool vb2_is_busy(struct vb2_queue *q) 1203 { 1204 return !!q->is_busy; 1205 } 1206 1207 /** 1208 * vb2_get_drv_priv() - return driver private data associated with the queue. 1209 * @q: pointer to &struct vb2_queue with videobuf2 queue. 1210 */ 1211 static inline void *vb2_get_drv_priv(struct vb2_queue *q) 1212 { 1213 return q->drv_priv; 1214 } 1215 1216 /** 1217 * vb2_set_plane_payload() - set bytesused for the plane @plane_no. 1218 * @vb: pointer to &struct vb2_buffer to which the plane in 1219 * question belongs to. 1220 * @plane_no: plane number for which payload should be set. 1221 * @size: payload in bytes. 1222 */ 1223 static inline void vb2_set_plane_payload(struct vb2_buffer *vb, 1224 unsigned int plane_no, unsigned long size) 1225 { 1226 /* 1227 * size must never be larger than the buffer length, so 1228 * warn and clamp to the buffer length if that's the case. 1229 */ 1230 if (plane_no < vb->num_planes) { 1231 if (WARN_ON_ONCE(size > vb->planes[plane_no].length)) 1232 size = vb->planes[plane_no].length; 1233 vb->planes[plane_no].bytesused = size; 1234 } 1235 } 1236 1237 /** 1238 * vb2_get_plane_payload() - get bytesused for the plane plane_no 1239 * @vb: pointer to &struct vb2_buffer to which the plane in 1240 * question belongs to. 1241 * @plane_no: plane number for which payload should be set. 1242 */ 1243 static inline unsigned long vb2_get_plane_payload(struct vb2_buffer *vb, 1244 unsigned int plane_no) 1245 { 1246 if (plane_no < vb->num_planes) 1247 return vb->planes[plane_no].bytesused; 1248 return 0; 1249 } 1250 1251 /** 1252 * vb2_plane_size() - return plane size in bytes. 1253 * @vb: pointer to &struct vb2_buffer to which the plane in 1254 * question belongs to. 1255 * @plane_no: plane number for which size should be returned. 1256 */ 1257 static inline unsigned long 1258 vb2_plane_size(struct vb2_buffer *vb, unsigned int plane_no) 1259 { 1260 if (plane_no < vb->num_planes) 1261 return vb->planes[plane_no].length; 1262 return 0; 1263 } 1264 1265 /** 1266 * vb2_start_streaming_called() - return streaming status of driver. 1267 * @q: pointer to &struct vb2_queue with videobuf2 queue. 1268 */ 1269 static inline bool vb2_start_streaming_called(struct vb2_queue *q) 1270 { 1271 return q->start_streaming_called; 1272 } 1273 1274 /** 1275 * vb2_clear_last_buffer_dequeued() - clear last buffer dequeued flag of queue. 1276 * @q: pointer to &struct vb2_queue with videobuf2 queue. 1277 */ 1278 static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue *q) 1279 { 1280 q->last_buffer_dequeued = false; 1281 } 1282 1283 /** 1284 * vb2_get_buffer() - get a buffer from a queue 1285 * @q: pointer to &struct vb2_queue with videobuf2 queue. 1286 * @index: buffer index 1287 * 1288 * This function obtains a buffer from a queue, by its index. 1289 * Keep in mind that there is no refcounting involved in this 1290 * operation, so the buffer lifetime should be taken into 1291 * consideration. 1292 */ 1293 static inline struct vb2_buffer *vb2_get_buffer(struct vb2_queue *q, 1294 unsigned int index) 1295 { 1296 if (!q->bufs) 1297 return NULL; 1298 1299 if (index >= q->max_num_buffers) 1300 return NULL; 1301 1302 if (test_bit(index, q->bufs_bitmap)) 1303 return q->bufs[index]; 1304 return NULL; 1305 } 1306 1307 /* 1308 * The following functions are not part of the vb2 core API, but are useful 1309 * functions for videobuf2-*. 1310 */ 1311 1312 /** 1313 * vb2_buffer_in_use() - return true if the buffer is in use and 1314 * the queue cannot be freed (by the means of VIDIOC_REQBUFS(0)) call. 1315 * 1316 * @vb: buffer for which plane size should be returned. 1317 * @q: pointer to &struct vb2_queue with videobuf2 queue. 1318 */ 1319 bool vb2_buffer_in_use(struct vb2_queue *q, struct vb2_buffer *vb); 1320 1321 /** 1322 * vb2_verify_memory_type() - Check whether the memory type and buffer type 1323 * passed to a buffer operation are compatible with the queue. 1324 * 1325 * @q: pointer to &struct vb2_queue with videobuf2 queue. 1326 * @memory: memory model, as defined by enum &vb2_memory. 1327 * @type: private buffer type whose content is defined by the vb2-core 1328 * caller. For example, for V4L2, it should match 1329 * the types defined on enum &v4l2_buf_type. 1330 */ 1331 int vb2_verify_memory_type(struct vb2_queue *q, 1332 enum vb2_memory memory, unsigned int type); 1333 1334 /** 1335 * vb2_request_object_is_buffer() - return true if the object is a buffer 1336 * 1337 * @obj: the request object. 1338 */ 1339 bool vb2_request_object_is_buffer(struct media_request_object *obj); 1340 1341 /** 1342 * vb2_request_buffer_cnt() - return the number of buffers in the request 1343 * 1344 * @req: the request. 1345 */ 1346 unsigned int vb2_request_buffer_cnt(struct media_request *req); 1347 1348 #endif /* _MEDIA_VIDEOBUF2_CORE_H */ 1349