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