drivers/media/v4l2-core/videobuf2-v4l2.c

   1 /*
   2  * videobuf2-v4l2.c - V4L2 driver helper framework
   3  *
   4  * Copyright (C) 2010 Samsung Electronics
   5  *
   6  * Author: Pawel Osciak <pawel@osciak.com>
   7  *         Marek Szyprowski <m.szyprowski@samsung.com>
   8  *
   9  * The vb2_thread implementation was based on code from videobuf-dvb.c:
  10  *      (c) 2004 Gerd Knorr <kraxel@bytesex.org> [SUSE Labs]
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation.
  15  */
  16
  17 #include <linux/err.h>
  18 #include <linux/kernel.h>
  19 #include <linux/module.h>
  20 #include <linux/mm.h>
  21 #include <linux/poll.h>
  22 #include <linux/slab.h>
  23 #include <linux/sched.h>
  24 #include <linux/freezer.h>
  25 #include <linux/kthread.h>
  26
  27 #include <media/v4l2-dev.h>
  28 #include <media/v4l2-fh.h>
  29 #include <media/v4l2-event.h>
  30 #include <media/v4l2-common.h>
  31
  32 #include <media/videobuf2-v4l2.h>
  33
  34 static int debug;
  35 module_param(debug, int, 0644);
  36
  37 #define dprintk(level, fmt, arg...)                                           \
  38         do {                                                                  \
  39                 if (debug >= level)                                           \
  40                         pr_info("vb2-v4l2: %s: " fmt, __func__, ## arg); \
  41         } while (0)
  42
  43 /* Flags that are set by the vb2 core */
  44 #define V4L2_BUFFER_MASK_FLAGS  (V4L2_BUF_FLAG_MAPPED | V4L2_BUF_FLAG_QUEUED | \
  45                                  V4L2_BUF_FLAG_DONE | V4L2_BUF_FLAG_ERROR | \
  46                                  V4L2_BUF_FLAG_PREPARED | \
  47                                  V4L2_BUF_FLAG_TIMESTAMP_MASK)
  48 /* Output buffer flags that should be passed on to the driver */
  49 #define V4L2_BUFFER_OUT_FLAGS   (V4L2_BUF_FLAG_PFRAME | V4L2_BUF_FLAG_BFRAME | \
  50                                  V4L2_BUF_FLAG_KEYFRAME | V4L2_BUF_FLAG_TIMECODE)
  51
  52 /**
  53  * __verify_planes_array() - verify that the planes array passed in struct
  54  * v4l2_buffer from userspace can be safely used
  55  */
  56 static int __verify_planes_array(struct vb2_buffer *vb, const struct v4l2_buffer *b)
  57 {
  58         if (!V4L2_TYPE_IS_MULTIPLANAR(b->type))
  59                 return 0;
  60
  61         /* Is memory for copying plane information present? */
  62         if (b->m.planes == NULL) {
  63                 dprintk(1, "multi-planar buffer passed but planes array not provided\n");
  64                 return -EINVAL;
  65         }
  66
  67         if (b->length < vb->num_planes || b->length > VB2_MAX_PLANES) {
  68                 dprintk(1, "incorrect planes array length, expected %d, got %d\n",
  69                         vb->num_planes, b->length);
  70                 return -EINVAL;
  71         }
  72
  73         return 0;
  74 }
  75
  76 static int __verify_planes_array_core(struct vb2_buffer *vb, const void *pb)
  77 {
  78         return __verify_planes_array(vb, pb);
  79 }
  80
  81 /**
  82  * __verify_length() - Verify that the bytesused value for each plane fits in
  83  * the plane length and that the data offset doesn't exceed the bytesused value.
  84  */
  85 static int __verify_length(struct vb2_buffer *vb, const struct v4l2_buffer *b)
  86 {
  87         unsigned int length;
  88         unsigned int bytesused;
  89         unsigned int plane;
  90
  91         if (!V4L2_TYPE_IS_OUTPUT(b->type))
  92                 return 0;
  93
  94         if (V4L2_TYPE_IS_MULTIPLANAR(b->type)) {
  95                 for (plane = 0; plane < vb->num_planes; ++plane) {
  96                         length = (b->memory == VB2_MEMORY_USERPTR ||
  97                                   b->memory == VB2_MEMORY_DMABUF)
  98                                ? b->m.planes[plane].length
  99                                 : vb->planes[plane].length;
 100                         bytesused = b->m.planes[plane].bytesused
 101                                   ? b->m.planes[plane].bytesused : length;
 102
 103                         if (b->m.planes[plane].bytesused > length)
 104                                 return -EINVAL;
 105
 106                         if (b->m.planes[plane].data_offset > 0 &&
 107                             b->m.planes[plane].data_offset >= bytesused)
 108                                 return -EINVAL;
 109                 }
 110         } else {
 111                 length = (b->memory == VB2_MEMORY_USERPTR)
 112                         ? b->length : vb->planes[0].length;
 113
 114                 if (b->bytesused > length)
 115                         return -EINVAL;
 116         }
 117
 118         return 0;
 119 }
 120
 121 static void __copy_timestamp(struct vb2_buffer *vb, const void *pb)
 122 {
 123         const struct v4l2_buffer *b = pb;
 124         struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
 125         struct vb2_queue *q = vb->vb2_queue;
 126
 127         if (q->is_output) {
 128                 /*
 129                  * For output buffers copy the timestamp if needed,
 130                  * and the timecode field and flag if needed.
 131                  */
 132                 if (q->copy_timestamp)
 133                         vb->timestamp = timeval_to_ns(&b->timestamp);
 134                 vbuf->flags |= b->flags & V4L2_BUF_FLAG_TIMECODE;
 135                 if (b->flags & V4L2_BUF_FLAG_TIMECODE)
 136                         vbuf->timecode = b->timecode;
 137         }
 138 };
 139
 140 static void vb2_warn_zero_bytesused(struct vb2_buffer *vb)
 141 {
 142         static bool check_once;
 143
 144         if (check_once)
 145                 return;
 146
 147         check_once = true;
 148         WARN_ON(1);
 149
 150         pr_warn("use of bytesused == 0 is deprecated and will be removed in the future,\n");
 151         if (vb->vb2_queue->allow_zero_bytesused)
 152                 pr_warn("use VIDIOC_DECODER_CMD(V4L2_DEC_CMD_STOP) instead.\n");
 153         else
 154                 pr_warn("use the actual size instead.\n");
 155 }
 156
 157 static int vb2_queue_or_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b,
 158                                     const char *opname)
 159 {
 160         if (b->type != q->type) {
 161                 dprintk(1, "%s: invalid buffer type\n", opname);
 162                 return -EINVAL;
 163         }
 164
 165         if (b->index >= q->num_buffers) {
 166                 dprintk(1, "%s: buffer index out of range\n", opname);
 167                 return -EINVAL;
 168         }
 169
 170         if (q->bufs[b->index] == NULL) {
 171                 /* Should never happen */
 172                 dprintk(1, "%s: buffer is NULL\n", opname);
 173                 return -EINVAL;
 174         }
 175
 176         if (b->memory != q->memory) {
 177                 dprintk(1, "%s: invalid memory type\n", opname);
 178                 return -EINVAL;
 179         }
 180
 181         return __verify_planes_array(q->bufs[b->index], b);
 182 }
 183
 184 /**
 185  * __fill_v4l2_buffer() - fill in a struct v4l2_buffer with information to be
 186  * returned to userspace
 187  */
 188 static void __fill_v4l2_buffer(struct vb2_buffer *vb, void *pb)
 189 {
 190         struct v4l2_buffer *b = pb;
 191         struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
 192         struct vb2_queue *q = vb->vb2_queue;
 193         unsigned int plane;
 194
 195         /* Copy back data such as timestamp, flags, etc. */
 196         b->index = vb->index;
 197         b->type = vb->type;
 198         b->memory = vb->memory;
 199         b->bytesused = 0;
 200
 201         b->flags = vbuf->flags;
 202         b->field = vbuf->field;
 203         b->timestamp = ns_to_timeval(vb->timestamp);
 204         b->timecode = vbuf->timecode;
 205         b->sequence = vbuf->sequence;
 206         b->reserved2 = 0;
 207         b->reserved = 0;
 208
 209         if (q->is_multiplanar) {
 210                 /*
 211                  * Fill in plane-related data if userspace provided an array
 212                  * for it. The caller has already verified memory and size.
 213                  */
 214                 b->length = vb->num_planes;
 215                 for (plane = 0; plane < vb->num_planes; ++plane) {
 216                         struct v4l2_plane *pdst = &b->m.planes[plane];
 217                         struct vb2_plane *psrc = &vb->planes[plane];
 218
 219                         pdst->bytesused = psrc->bytesused;
 220                         pdst->length = psrc->length;
 221                         if (q->memory == VB2_MEMORY_MMAP)
 222                                 pdst->m.mem_offset = psrc->m.offset;
 223                         else if (q->memory == VB2_MEMORY_USERPTR)
 224                                 pdst->m.userptr = psrc->m.userptr;
 225                         else if (q->memory == VB2_MEMORY_DMABUF)
 226                                 pdst->m.fd = psrc->m.fd;
 227                         pdst->data_offset = psrc->data_offset;
 228                         memset(pdst->reserved, 0, sizeof(pdst->reserved));
 229                 }
 230         } else {
 231                 /*
 232                  * We use length and offset in v4l2_planes array even for
 233                  * single-planar buffers, but userspace does not.
 234                  */
 235                 b->length = vb->planes[0].length;
 236                 b->bytesused = vb->planes[0].bytesused;
 237                 if (q->memory == VB2_MEMORY_MMAP)
 238                         b->m.offset = vb->planes[0].m.offset;
 239                 else if (q->memory == VB2_MEMORY_USERPTR)
 240                         b->m.userptr = vb->planes[0].m.userptr;
 241                 else if (q->memory == VB2_MEMORY_DMABUF)
 242                         b->m.fd = vb->planes[0].m.fd;
 243         }
 244
 245         /*
 246          * Clear any buffer state related flags.
 247          */
 248         b->flags &= ~V4L2_BUFFER_MASK_FLAGS;
 249         b->flags |= q->timestamp_flags & V4L2_BUF_FLAG_TIMESTAMP_MASK;
 250         if (!q->copy_timestamp) {
 251                 /*
 252                  * For non-COPY timestamps, drop timestamp source bits
 253                  * and obtain the timestamp source from the queue.
 254                  */
 255                 b->flags &= ~V4L2_BUF_FLAG_TSTAMP_SRC_MASK;
 256                 b->flags |= q->timestamp_flags & V4L2_BUF_FLAG_TSTAMP_SRC_MASK;
 257         }
 258
 259         switch (vb->state) {
 260         case VB2_BUF_STATE_QUEUED:
 261         case VB2_BUF_STATE_ACTIVE:
 262                 b->flags |= V4L2_BUF_FLAG_QUEUED;
 263                 break;
 264         case VB2_BUF_STATE_ERROR:
 265                 b->flags |= V4L2_BUF_FLAG_ERROR;
 266                 /* fall through */
 267         case VB2_BUF_STATE_DONE:
 268                 b->flags |= V4L2_BUF_FLAG_DONE;
 269                 break;
 270         case VB2_BUF_STATE_PREPARED:
 271                 b->flags |= V4L2_BUF_FLAG_PREPARED;
 272                 break;
 273         case VB2_BUF_STATE_PREPARING:
 274         case VB2_BUF_STATE_DEQUEUED:
 275         case VB2_BUF_STATE_REQUEUEING:
 276                 /* nothing */
 277                 break;
 278         }
 279
 280         if (vb2_buffer_in_use(q, vb))
 281                 b->flags |= V4L2_BUF_FLAG_MAPPED;
 282
 283         if (!q->is_output &&
 284                 b->flags & V4L2_BUF_FLAG_DONE &&
 285                 b->flags & V4L2_BUF_FLAG_LAST)
 286                 q->last_buffer_dequeued = true;
 287 }
 288
 289 /**
 290  * __fill_vb2_buffer() - fill a vb2_buffer with information provided in a
 291  * v4l2_buffer by the userspace. It also verifies that struct
 292  * v4l2_buffer has a valid number of planes.
 293  */
 294 static int __fill_vb2_buffer(struct vb2_buffer *vb,
 295                 const void *pb, struct vb2_plane *planes)
 296 {
 297         struct vb2_queue *q = vb->vb2_queue;
 298         const struct v4l2_buffer *b = pb;
 299         struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
 300         unsigned int plane;
 301         int ret;
 302
 303         ret = __verify_length(vb, b);
 304         if (ret < 0) {
 305                 dprintk(1, "plane parameters verification failed: %d\n", ret);
 306                 return ret;
 307         }
 308         if (b->field == V4L2_FIELD_ALTERNATE && q->is_output) {
 309                 /*
 310                  * If the format's field is ALTERNATE, then the buffer's field
 311                  * should be either TOP or BOTTOM, not ALTERNATE since that
 312                  * makes no sense. The driver has to know whether the
 313                  * buffer represents a top or a bottom field in order to
 314                  * program any DMA correctly. Using ALTERNATE is wrong, since
 315                  * that just says that it is either a top or a bottom field,
 316                  * but not which of the two it is.
 317                  */
 318                 dprintk(1, "the field is incorrectly set to ALTERNATE for an output buffer\n");
 319                 return -EINVAL;
 320         }
 321         vb->timestamp = 0;
 322         vbuf->sequence = 0;
 323
 324         if (V4L2_TYPE_IS_MULTIPLANAR(b->type)) {
 325                 if (b->memory == VB2_MEMORY_USERPTR) {
 326                         for (plane = 0; plane < vb->num_planes; ++plane) {
 327                                 planes[plane].m.userptr =
 328                                         b->m.planes[plane].m.userptr;
 329                                 planes[plane].length =
 330                                         b->m.planes[plane].length;
 331                         }
 332                 }
 333                 if (b->memory == VB2_MEMORY_DMABUF) {
 334                         for (plane = 0; plane < vb->num_planes; ++plane) {
 335                                 planes[plane].m.fd =
 336                                         b->m.planes[plane].m.fd;
 337                                 planes[plane].length =
 338                                         b->m.planes[plane].length;
 339                         }
 340                 }
 341
 342                 /* Fill in driver-provided information for OUTPUT types */
 343                 if (V4L2_TYPE_IS_OUTPUT(b->type)) {
 344                         /*
 345                          * Will have to go up to b->length when API starts
 346                          * accepting variable number of planes.
 347                          *
 348                          * If bytesused == 0 for the output buffer, then fall
 349                          * back to the full buffer size. In that case
 350                          * userspace clearly never bothered to set it and
 351                          * it's a safe assumption that they really meant to
 352                          * use the full plane sizes.
 353                          *
 354                          * Some drivers, e.g. old codec drivers, use bytesused == 0
 355                          * as a way to indicate that streaming is finished.
 356                          * In that case, the driver should use the
 357                          * allow_zero_bytesused flag to keep old userspace
 358                          * applications working.
 359                          */
 360                         for (plane = 0; plane < vb->num_planes; ++plane) {
 361                                 struct vb2_plane *pdst = &planes[plane];
 362                                 struct v4l2_plane *psrc = &b->m.planes[plane];
 363
 364                                 if (psrc->bytesused == 0)
 365                                         vb2_warn_zero_bytesused(vb);
 366
 367                                 if (vb->vb2_queue->allow_zero_bytesused)
 368                                         pdst->bytesused = psrc->bytesused;
 369                                 else
 370                                         pdst->bytesused = psrc->bytesused ?
 371                                                 psrc->bytesused : pdst->length;
 372                                 pdst->data_offset = psrc->data_offset;
 373                         }
 374                 }
 375         } else {
 376                 /*
 377                  * Single-planar buffers do not use planes array,
 378                  * so fill in relevant v4l2_buffer struct fields instead.
 379                  * In videobuf we use our internal V4l2_planes struct for
 380                  * single-planar buffers as well, for simplicity.
 381                  *
 382                  * If bytesused == 0 for the output buffer, then fall back
 383                  * to the full buffer size as that's a sensible default.
 384                  *
 385                  * Some drivers, e.g. old codec drivers, use bytesused == 0 as
 386                  * a way to indicate that streaming is finished. In that case,
 387                  * the driver should use the allow_zero_bytesused flag to keep
 388                  * old userspace applications working.
 389                  */
 390                 if (b->memory == VB2_MEMORY_USERPTR) {
 391                         planes[0].m.userptr = b->m.userptr;
 392                         planes[0].length = b->length;
 393                 }
 394
 395                 if (b->memory == VB2_MEMORY_DMABUF) {
 396                         planes[0].m.fd = b->m.fd;
 397                         planes[0].length = b->length;
 398                 }
 399
 400                 if (V4L2_TYPE_IS_OUTPUT(b->type)) {
 401                         if (b->bytesused == 0)
 402                                 vb2_warn_zero_bytesused(vb);
 403
 404                         if (vb->vb2_queue->allow_zero_bytesused)
 405                                 planes[0].bytesused = b->bytesused;
 406                         else
 407                                 planes[0].bytesused = b->bytesused ?
 408                                         b->bytesused : planes[0].length;
 409                 } else
 410                         planes[0].bytesused = 0;
 411
 412         }
 413
 414         /* Zero flags that the vb2 core handles */
 415         vbuf->flags = b->flags & ~V4L2_BUFFER_MASK_FLAGS;
 416         if (!vb->vb2_queue->copy_timestamp || !V4L2_TYPE_IS_OUTPUT(b->type)) {
 417                 /*
 418                  * Non-COPY timestamps and non-OUTPUT queues will get
 419                  * their timestamp and timestamp source flags from the
 420                  * queue.
 421                  */
 422                 vbuf->flags &= ~V4L2_BUF_FLAG_TSTAMP_SRC_MASK;
 423         }
 424
 425         if (V4L2_TYPE_IS_OUTPUT(b->type)) {
 426                 /*
 427                  * For output buffers mask out the timecode flag:
 428                  * this will be handled later in vb2_qbuf().
 429                  * The 'field' is valid metadata for this output buffer
 430                  * and so that needs to be copied here.
 431                  */
 432                 vbuf->flags &= ~V4L2_BUF_FLAG_TIMECODE;
 433                 vbuf->field = b->field;
 434         } else {
 435                 /* Zero any output buffer flags as this is a capture buffer */
 436                 vbuf->flags &= ~V4L2_BUFFER_OUT_FLAGS;
 437         }
 438
 439         return 0;
 440 }
 441
 442 static const struct vb2_buf_ops v4l2_buf_ops = {
 443         .verify_planes_array    = __verify_planes_array_core,
 444         .fill_user_buffer       = __fill_v4l2_buffer,
 445         .fill_vb2_buffer        = __fill_vb2_buffer,
 446         .copy_timestamp         = __copy_timestamp,
 447 };
 448
 449 /**
 450  * vb2_querybuf() - query video buffer information
 451  * @q:          videobuf queue
 452  * @b:          buffer struct passed from userspace to vidioc_querybuf handler
 453  *              in driver
 454  *
 455  * Should be called from vidioc_querybuf ioctl handler in driver.
 456  * This function will verify the passed v4l2_buffer structure and fill the
 457  * relevant information for the userspace.
 458  *
 459  * The return values from this function are intended to be directly returned
 460  * from vidioc_querybuf handler in driver.
 461  */
 462 int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b)
 463 {
 464         struct vb2_buffer *vb;
 465         int ret;
 466
 467         if (b->type != q->type) {
 468                 dprintk(1, "wrong buffer type\n");
 469                 return -EINVAL;
 470         }
 471
 472         if (b->index >= q->num_buffers) {
 473                 dprintk(1, "buffer index out of range\n");
 474                 return -EINVAL;
 475         }
 476         vb = q->bufs[b->index];
 477         ret = __verify_planes_array(vb, b);
 478         if (!ret)
 479                 vb2_core_querybuf(q, b->index, b);
 480         return ret;
 481 }
 482 EXPORT_SYMBOL(vb2_querybuf);
 483
 484 int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
 485 {
 486         int ret = vb2_verify_memory_type(q, req->memory, req->type);
 487
 488         return ret ? ret : vb2_core_reqbufs(q, req->memory, &req->count);
 489 }
 490 EXPORT_SYMBOL_GPL(vb2_reqbufs);
 491
 492 int vb2_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b)
 493 {
 494         int ret;
 495
 496         if (vb2_fileio_is_active(q)) {
 497                 dprintk(1, "file io in progress\n");
 498                 return -EBUSY;
 499         }
 500
 501         ret = vb2_queue_or_prepare_buf(q, b, "prepare_buf");
 502
 503         return ret ? ret : vb2_core_prepare_buf(q, b->index, b);
 504 }
 505 EXPORT_SYMBOL_GPL(vb2_prepare_buf);
 506
 507 int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
 508 {
 509         unsigned requested_planes = 1;
 510         unsigned requested_sizes[VIDEO_MAX_PLANES];
 511         struct v4l2_format *f = &create->format;
 512         int ret = vb2_verify_memory_type(q, create->memory, f->type);
 513         unsigned i;
 514
 515         create->index = q->num_buffers;
 516         if (create->count == 0)
 517                 return ret != -EBUSY ? ret : 0;
 518
 519         switch (f->type) {
 520         case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
 521         case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
 522                 requested_planes = f->fmt.pix_mp.num_planes;
 523                 if (requested_planes == 0 ||
 524                     requested_planes > VIDEO_MAX_PLANES)
 525                         return -EINVAL;
 526                 for (i = 0; i < requested_planes; i++)
 527                         requested_sizes[i] =
 528                                 f->fmt.pix_mp.plane_fmt[i].sizeimage;
 529                 break;
 530         case V4L2_BUF_TYPE_VIDEO_CAPTURE:
 531         case V4L2_BUF_TYPE_VIDEO_OUTPUT:
 532                 requested_sizes[0] = f->fmt.pix.sizeimage;
 533                 break;
 534         case V4L2_BUF_TYPE_VBI_CAPTURE:
 535         case V4L2_BUF_TYPE_VBI_OUTPUT:
 536                 requested_sizes[0] = f->fmt.vbi.samples_per_line *
 537                         (f->fmt.vbi.count[0] + f->fmt.vbi.count[1]);
 538                 break;
 539         case V4L2_BUF_TYPE_SLICED_VBI_CAPTURE:
 540         case V4L2_BUF_TYPE_SLICED_VBI_OUTPUT:
 541                 requested_sizes[0] = f->fmt.sliced.io_size;
 542                 break;
 543         case V4L2_BUF_TYPE_SDR_CAPTURE:
 544         case V4L2_BUF_TYPE_SDR_OUTPUT:
 545                 requested_sizes[0] = f->fmt.sdr.buffersize;
 546                 break;
 547         default:
 548                 return -EINVAL;
 549         }
 550         for (i = 0; i < requested_planes; i++)
 551                 if (requested_sizes[i] == 0)
 552                         return -EINVAL;
 553         return ret ? ret : vb2_core_create_bufs(q, create->memory,
 554                 &create->count, requested_planes, requested_sizes);
 555 }
 556 EXPORT_SYMBOL_GPL(vb2_create_bufs);
 557
 558 int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)
 559 {
 560         int ret;
 561
 562         if (vb2_fileio_is_active(q)) {
 563                 dprintk(1, "file io in progress\n");
 564                 return -EBUSY;
 565         }
 566
 567         ret = vb2_queue_or_prepare_buf(q, b, "qbuf");
 568         return ret ? ret : vb2_core_qbuf(q, b->index, b);
 569 }
 570 EXPORT_SYMBOL_GPL(vb2_qbuf);
 571
 572 int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking)
 573 {
 574         int ret;
 575
 576         if (vb2_fileio_is_active(q)) {
 577                 dprintk(1, "file io in progress\n");
 578                 return -EBUSY;
 579         }
 580
 581         if (b->type != q->type) {
 582                 dprintk(1, "invalid buffer type\n");
 583                 return -EINVAL;
 584         }
 585
 586         ret = vb2_core_dqbuf(q, NULL, b, nonblocking);
 587
 588         /*
 589          *  After calling the VIDIOC_DQBUF V4L2_BUF_FLAG_DONE must be
 590          *  cleared.
 591          */
 592         b->flags &= ~V4L2_BUF_FLAG_DONE;
 593
 594         return ret;
 595 }
 596 EXPORT_SYMBOL_GPL(vb2_dqbuf);
 597
 598 int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type)
 599 {
 600         if (vb2_fileio_is_active(q)) {
 601                 dprintk(1, "file io in progress\n");
 602                 return -EBUSY;
 603         }
 604         return vb2_core_streamon(q, type);
 605 }
 606 EXPORT_SYMBOL_GPL(vb2_streamon);
 607
 608 int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type)
 609 {
 610         if (vb2_fileio_is_active(q)) {
 611                 dprintk(1, "file io in progress\n");
 612                 return -EBUSY;
 613         }
 614         return vb2_core_streamoff(q, type);
 615 }
 616 EXPORT_SYMBOL_GPL(vb2_streamoff);
 617
 618 int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb)
 619 {
 620         return vb2_core_expbuf(q, &eb->fd, eb->type, eb->index,
 621                                 eb->plane, eb->flags);
 622 }
 623 EXPORT_SYMBOL_GPL(vb2_expbuf);
 624
 625 int vb2_queue_init(struct vb2_queue *q)
 626 {
 627         /*
 628          * Sanity check
 629          */
 630         if (WARN_ON(!q)                   ||
 631             WARN_ON(q->timestamp_flags &
 632                     ~(V4L2_BUF_FLAG_TIMESTAMP_MASK |
 633                       V4L2_BUF_FLAG_TSTAMP_SRC_MASK)))
 634                 return -EINVAL;
 635
 636         /* Warn that the driver should choose an appropriate timestamp type */
 637         WARN_ON((q->timestamp_flags & V4L2_BUF_FLAG_TIMESTAMP_MASK) ==
 638                 V4L2_BUF_FLAG_TIMESTAMP_UNKNOWN);
 639
 640         /* Warn that vb2_memory should match with v4l2_memory */
 641         if (WARN_ON(VB2_MEMORY_MMAP != (int)V4L2_MEMORY_MMAP)
 642                 || WARN_ON(VB2_MEMORY_USERPTR != (int)V4L2_MEMORY_USERPTR)
 643                 || WARN_ON(VB2_MEMORY_DMABUF != (int)V4L2_MEMORY_DMABUF))
 644                 return -EINVAL;
 645
 646         if (q->buf_struct_size == 0)
 647                 q->buf_struct_size = sizeof(struct vb2_v4l2_buffer);
 648
 649         q->buf_ops = &v4l2_buf_ops;
 650         q->is_multiplanar = V4L2_TYPE_IS_MULTIPLANAR(q->type);
 651         q->is_output = V4L2_TYPE_IS_OUTPUT(q->type);
 652         q->copy_timestamp = (q->timestamp_flags & V4L2_BUF_FLAG_TIMESTAMP_MASK)
 653                         == V4L2_BUF_FLAG_TIMESTAMP_COPY;
 654         /*
 655          * For compatibility with vb1: if QBUF hasn't been called yet, then
 656          * return POLLERR as well. This only affects capture queues, output
 657          * queues will always initialize waiting_for_buffers to false.
 658          */
 659         q->quirk_poll_must_check_waiting_for_buffers = true;
 660
 661         return vb2_core_queue_init(q);
 662 }
 663 EXPORT_SYMBOL_GPL(vb2_queue_init);
 664
 665 void vb2_queue_release(struct vb2_queue *q)
 666 {
 667         vb2_core_queue_release(q);
 668 }
 669 EXPORT_SYMBOL_GPL(vb2_queue_release);
 670
 671 unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait)
 672 {
 673         struct video_device *vfd = video_devdata(file);
 674         unsigned long req_events = poll_requested_events(wait);
 675         unsigned int res = 0;
 676
 677         if (test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags)) {
 678                 struct v4l2_fh *fh = file->private_data;
 679
 680                 if (v4l2_event_pending(fh))
 681                         res = POLLPRI;
 682                 else if (req_events & POLLPRI)
 683                         poll_wait(file, &fh->wait, wait);
 684         }
 685
 686         return res | vb2_core_poll(q, file, wait);
 687 }
 688 EXPORT_SYMBOL_GPL(vb2_poll);
 689
 690 /*
 691  * The following functions are not part of the vb2 core API, but are helper
 692  * functions that plug into struct v4l2_ioctl_ops, struct v4l2_file_operations
 693  * and struct vb2_ops.
 694  * They contain boilerplate code that most if not all drivers have to do
 695  * and so they simplify the driver code.
 696  */
 697
 698 /* The queue is busy if there is a owner and you are not that owner. */
 699 static inline bool vb2_queue_is_busy(struct video_device *vdev, struct file *file)
 700 {
 701         return vdev->queue->owner && vdev->queue->owner != file->private_data;
 702 }
 703
 704 /* vb2 ioctl helpers */
 705
 706 int vb2_ioctl_reqbufs(struct file *file, void *priv,
 707                           struct v4l2_requestbuffers *p)
 708 {
 709         struct video_device *vdev = video_devdata(file);
 710         int res = vb2_verify_memory_type(vdev->queue, p->memory, p->type);
 711
 712         if (res)
 713                 return res;
 714         if (vb2_queue_is_busy(vdev, file))
 715                 return -EBUSY;
 716         res = vb2_core_reqbufs(vdev->queue, p->memory, &p->count);
 717         /* If count == 0, then the owner has released all buffers and he
 718            is no longer owner of the queue. Otherwise we have a new owner. */
 719         if (res == 0)
 720                 vdev->queue->owner = p->count ? file->private_data : NULL;
 721         return res;
 722 }
 723 EXPORT_SYMBOL_GPL(vb2_ioctl_reqbufs);
 724
 725 int vb2_ioctl_create_bufs(struct file *file, void *priv,
 726                           struct v4l2_create_buffers *p)
 727 {
 728         struct video_device *vdev = video_devdata(file);
 729         int res = vb2_verify_memory_type(vdev->queue, p->memory,
 730                         p->format.type);
 731
 732         p->index = vdev->queue->num_buffers;
 733         /*
 734          * If count == 0, then just check if memory and type are valid.
 735          * Any -EBUSY result from vb2_verify_memory_type can be mapped to 0.
 736          */
 737         if (p->count == 0)
 738                 return res != -EBUSY ? res : 0;
 739         if (res)
 740                 return res;
 741         if (vb2_queue_is_busy(vdev, file))
 742                 return -EBUSY;
 743
 744         res = vb2_create_bufs(vdev->queue, p);
 745         if (res == 0)
 746                 vdev->queue->owner = file->private_data;
 747         return res;
 748 }
 749 EXPORT_SYMBOL_GPL(vb2_ioctl_create_bufs);
 750
 751 int vb2_ioctl_prepare_buf(struct file *file, void *priv,
 752                           struct v4l2_buffer *p)
 753 {
 754         struct video_device *vdev = video_devdata(file);
 755
 756         if (vb2_queue_is_busy(vdev, file))
 757                 return -EBUSY;
 758         return vb2_prepare_buf(vdev->queue, p);
 759 }
 760 EXPORT_SYMBOL_GPL(vb2_ioctl_prepare_buf);
 761
 762 int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p)
 763 {
 764         struct video_device *vdev = video_devdata(file);
 765
 766         /* No need to call vb2_queue_is_busy(), anyone can query buffers. */
 767         return vb2_querybuf(vdev->queue, p);
 768 }
 769 EXPORT_SYMBOL_GPL(vb2_ioctl_querybuf);
 770
 771 int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p)
 772 {
 773         struct video_device *vdev = video_devdata(file);
 774
 775         if (vb2_queue_is_busy(vdev, file))
 776                 return -EBUSY;
 777         return vb2_qbuf(vdev->queue, p);
 778 }
 779 EXPORT_SYMBOL_GPL(vb2_ioctl_qbuf);
 780
 781 int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p)
 782 {
 783         struct video_device *vdev = video_devdata(file);
 784
 785         if (vb2_queue_is_busy(vdev, file))
 786                 return -EBUSY;
 787         return vb2_dqbuf(vdev->queue, p, file->f_flags & O_NONBLOCK);
 788 }
 789 EXPORT_SYMBOL_GPL(vb2_ioctl_dqbuf);
 790
 791 int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i)
 792 {
 793         struct video_device *vdev = video_devdata(file);
 794
 795         if (vb2_queue_is_busy(vdev, file))
 796                 return -EBUSY;
 797         return vb2_streamon(vdev->queue, i);
 798 }
 799 EXPORT_SYMBOL_GPL(vb2_ioctl_streamon);
 800
 801 int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i)
 802 {
 803         struct video_device *vdev = video_devdata(file);
 804
 805         if (vb2_queue_is_busy(vdev, file))
 806                 return -EBUSY;
 807         return vb2_streamoff(vdev->queue, i);
 808 }
 809 EXPORT_SYMBOL_GPL(vb2_ioctl_streamoff);
 810
 811 int vb2_ioctl_expbuf(struct file *file, void *priv, struct v4l2_exportbuffer *p)
 812 {
 813         struct video_device *vdev = video_devdata(file);
 814
 815         if (vb2_queue_is_busy(vdev, file))
 816                 return -EBUSY;
 817         return vb2_expbuf(vdev->queue, p);
 818 }
 819 EXPORT_SYMBOL_GPL(vb2_ioctl_expbuf);
 820
 821 /* v4l2_file_operations helpers */
 822
 823 int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma)
 824 {
 825         struct video_device *vdev = video_devdata(file);
 826
 827         return vb2_mmap(vdev->queue, vma);
 828 }
 829 EXPORT_SYMBOL_GPL(vb2_fop_mmap);
 830
 831 int _vb2_fop_release(struct file *file, struct mutex *lock)
 832 {
 833         struct video_device *vdev = video_devdata(file);
 834
 835         if (lock)
 836                 mutex_lock(lock);
 837         if (file->private_data == vdev->queue->owner) {
 838                 vb2_queue_release(vdev->queue);
 839                 vdev->queue->owner = NULL;
 840         }
 841         if (lock)
 842                 mutex_unlock(lock);
 843         return v4l2_fh_release(file);
 844 }
 845 EXPORT_SYMBOL_GPL(_vb2_fop_release);
 846
 847 int vb2_fop_release(struct file *file)
 848 {
 849         struct video_device *vdev = video_devdata(file);
 850         struct mutex *lock = vdev->queue->lock ? vdev->queue->lock : vdev->lock;
 851
 852         return _vb2_fop_release(file, lock);
 853 }
 854 EXPORT_SYMBOL_GPL(vb2_fop_release);
 855
 856 ssize_t vb2_fop_write(struct file *file, const char __user *buf,
 857                 size_t count, loff_t *ppos)
 858 {
 859         struct video_device *vdev = video_devdata(file);
 860         struct mutex *lock = vdev->queue->lock ? vdev->queue->lock : vdev->lock;
 861         int err = -EBUSY;
 862
 863         if (!(vdev->queue->io_modes & VB2_WRITE))
 864                 return -EINVAL;
 865         if (lock && mutex_lock_interruptible(lock))
 866                 return -ERESTARTSYS;
 867         if (vb2_queue_is_busy(vdev, file))
 868                 goto exit;
 869         err = vb2_write(vdev->queue, buf, count, ppos,
 870                        file->f_flags & O_NONBLOCK);
 871         if (vdev->queue->fileio)
 872                 vdev->queue->owner = file->private_data;
 873 exit:
 874         if (lock)
 875                 mutex_unlock(lock);
 876         return err;
 877 }
 878 EXPORT_SYMBOL_GPL(vb2_fop_write);
 879
 880 ssize_t vb2_fop_read(struct file *file, char __user *buf,
 881                 size_t count, loff_t *ppos)
 882 {
 883         struct video_device *vdev = video_devdata(file);
 884         struct mutex *lock = vdev->queue->lock ? vdev->queue->lock : vdev->lock;
 885         int err = -EBUSY;
 886
 887         if (!(vdev->queue->io_modes & VB2_READ))
 888                 return -EINVAL;
 889         if (lock && mutex_lock_interruptible(lock))
 890                 return -ERESTARTSYS;
 891         if (vb2_queue_is_busy(vdev, file))
 892                 goto exit;
 893         err = vb2_read(vdev->queue, buf, count, ppos,
 894                        file->f_flags & O_NONBLOCK);
 895         if (vdev->queue->fileio)
 896                 vdev->queue->owner = file->private_data;
 897 exit:
 898         if (lock)
 899                 mutex_unlock(lock);
 900         return err;
 901 }
 902 EXPORT_SYMBOL_GPL(vb2_fop_read);
 903
 904 unsigned int vb2_fop_poll(struct file *file, poll_table *wait)
 905 {
 906         struct video_device *vdev = video_devdata(file);
 907         struct vb2_queue *q = vdev->queue;
 908         struct mutex *lock = q->lock ? q->lock : vdev->lock;
 909         unsigned res;
 910         void *fileio;
 911
 912         /*
 913          * If this helper doesn't know how to lock, then you shouldn't be using
 914          * it but you should write your own.
 915          */
 916         WARN_ON(!lock);
 917
 918         if (lock && mutex_lock_interruptible(lock))
 919                 return POLLERR;
 920
 921         fileio = q->fileio;
 922
 923         res = vb2_poll(vdev->queue, file, wait);
 924
 925         /* If fileio was started, then we have a new queue owner. */
 926         if (!fileio && q->fileio)
 927                 q->owner = file->private_data;
 928         if (lock)
 929                 mutex_unlock(lock);
 930         return res;
 931 }
 932 EXPORT_SYMBOL_GPL(vb2_fop_poll);
 933
 934 #ifndef CONFIG_MMU
 935 unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr,
 936                 unsigned long len, unsigned long pgoff, unsigned long flags)
 937 {
 938         struct video_device *vdev = video_devdata(file);
 939
 940         return vb2_get_unmapped_area(vdev->queue, addr, len, pgoff, flags);
 941 }
 942 EXPORT_SYMBOL_GPL(vb2_fop_get_unmapped_area);
 943 #endif
 944
 945 /* vb2_ops helpers. Only use if vq->lock is non-NULL. */
 946
 947 void vb2_ops_wait_prepare(struct vb2_queue *vq)
 948 {
 949         mutex_unlock(vq->lock);
 950 }
 951 EXPORT_SYMBOL_GPL(vb2_ops_wait_prepare);
 952
 953 void vb2_ops_wait_finish(struct vb2_queue *vq)
 954 {
 955         mutex_lock(vq->lock);
 956 }
 957 EXPORT_SYMBOL_GPL(vb2_ops_wait_finish);
 958
 959 MODULE_DESCRIPTION("Driver helper framework for Video for Linux 2");
 960 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>, Marek Szyprowski");
 961 MODULE_LICENSE("GPL");