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

   1 /*
   2  * generic helper functions for handling video4linux capture buffers
   3  *
   4  * (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org>
   5  *
   6  * Highly based on video-buf written originally by:
   7  * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
   8  * (c) 2006 Mauro Carvalho Chehab, <mchehab@infradead.org>
   9  * (c) 2006 Ted Walther and John Sokol
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2
  14  */
  15
  16 #include <linux/init.h>
  17 #include <linux/module.h>
  18 #include <linux/moduleparam.h>
  19 #include <linux/mm.h>
  20 #include <linux/sched.h>
  21 #include <linux/slab.h>
  22 #include <linux/interrupt.h>
  23
  24 #include <media/videobuf-core.h>
  25
  26 #define MAGIC_BUFFER 0x20070728
  27 #define MAGIC_CHECK(is, should)                                         \
  28         do {                                                            \
  29                 if (unlikely((is) != (should))) {                       \
  30                         printk(KERN_ERR                                 \
  31                                 "magic mismatch: %x (expected %x)\n",   \
  32                                         is, should);                    \
  33                         BUG();                                          \
  34                 }                                                       \
  35         } while (0)
  36
  37 static int debug;
  38 module_param(debug, int, 0644);
  39
  40 MODULE_DESCRIPTION("helper module to manage video4linux buffers");
  41 MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@infradead.org>");
  42 MODULE_LICENSE("GPL");
  43
  44 #define dprintk(level, fmt, arg...)                                     \
  45         do {                                                            \
  46                 if (debug >= level)                                     \
  47                         printk(KERN_DEBUG "vbuf: " fmt, ## arg);        \
  48         } while (0)
  49
  50 /* --------------------------------------------------------------------- */
  51
  52 #define CALL(q, f, arg...)                                              \
  53         ((q->int_ops->f) ? q->int_ops->f(arg) : 0)
  54 #define CALLPTR(q, f, arg...)                                           \
  55         ((q->int_ops->f) ? q->int_ops->f(arg) : NULL)
  56
  57 struct videobuf_buffer *videobuf_alloc_vb(struct videobuf_queue *q)
  58 {
  59         struct videobuf_buffer *vb;
  60
  61         BUG_ON(q->msize < sizeof(*vb));
  62
  63         if (!q->int_ops || !q->int_ops->alloc_vb) {
  64                 printk(KERN_ERR "No specific ops defined!\n");
  65                 BUG();
  66         }
  67
  68         vb = q->int_ops->alloc_vb(q->msize);
  69         if (NULL != vb) {
  70                 init_waitqueue_head(&vb->done);
  71                 vb->magic = MAGIC_BUFFER;
  72         }
  73
  74         return vb;
  75 }
  76 EXPORT_SYMBOL_GPL(videobuf_alloc_vb);
  77
  78 static int state_neither_active_nor_queued(struct videobuf_queue *q,
  79                                            struct videobuf_buffer *vb)
  80 {
  81         unsigned long flags;
  82         bool rc;
  83
  84         spin_lock_irqsave(q->irqlock, flags);
  85         rc = vb->state != VIDEOBUF_ACTIVE && vb->state != VIDEOBUF_QUEUED;
  86         spin_unlock_irqrestore(q->irqlock, flags);
  87         return rc;
  88 };
  89
  90 int videobuf_waiton(struct videobuf_queue *q, struct videobuf_buffer *vb,
  91                 int non_blocking, int intr)
  92 {
  93         bool is_ext_locked;
  94         int ret = 0;
  95
  96         MAGIC_CHECK(vb->magic, MAGIC_BUFFER);
  97
  98         if (non_blocking) {
  99                 if (state_neither_active_nor_queued(q, vb))
 100                         return 0;
 101                 return -EAGAIN;
 102         }
 103
 104         is_ext_locked = q->ext_lock && mutex_is_locked(q->ext_lock);
 105
 106         /* Release vdev lock to prevent this wait from blocking outside access to
 107            the device. */
 108         if (is_ext_locked)
 109                 mutex_unlock(q->ext_lock);
 110         if (intr)
 111                 ret = wait_event_interruptible(vb->done,
 112                                         state_neither_active_nor_queued(q, vb));
 113         else
 114                 wait_event(vb->done, state_neither_active_nor_queued(q, vb));
 115         /* Relock */
 116         if (is_ext_locked)
 117                 mutex_lock(q->ext_lock);
 118
 119         return ret;
 120 }
 121 EXPORT_SYMBOL_GPL(videobuf_waiton);
 122
 123 int videobuf_iolock(struct videobuf_queue *q, struct videobuf_buffer *vb,
 124                     struct v4l2_framebuffer *fbuf)
 125 {
 126         MAGIC_CHECK(vb->magic, MAGIC_BUFFER);
 127         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 128
 129         return CALL(q, iolock, q, vb, fbuf);
 130 }
 131 EXPORT_SYMBOL_GPL(videobuf_iolock);
 132
 133 void *videobuf_queue_to_vaddr(struct videobuf_queue *q,
 134                               struct videobuf_buffer *buf)
 135 {
 136         if (q->int_ops->vaddr)
 137                 return q->int_ops->vaddr(buf);
 138         return NULL;
 139 }
 140 EXPORT_SYMBOL_GPL(videobuf_queue_to_vaddr);
 141
 142 /* --------------------------------------------------------------------- */
 143
 144
 145 void videobuf_queue_core_init(struct videobuf_queue *q,
 146                          const struct videobuf_queue_ops *ops,
 147                          struct device *dev,
 148                          spinlock_t *irqlock,
 149                          enum v4l2_buf_type type,
 150                          enum v4l2_field field,
 151                          unsigned int msize,
 152                          void *priv,
 153                          struct videobuf_qtype_ops *int_ops,
 154                          struct mutex *ext_lock)
 155 {
 156         BUG_ON(!q);
 157         memset(q, 0, sizeof(*q));
 158         q->irqlock   = irqlock;
 159         q->ext_lock  = ext_lock;
 160         q->dev       = dev;
 161         q->type      = type;
 162         q->field     = field;
 163         q->msize     = msize;
 164         q->ops       = ops;
 165         q->priv_data = priv;
 166         q->int_ops   = int_ops;
 167
 168         /* All buffer operations are mandatory */
 169         BUG_ON(!q->ops->buf_setup);
 170         BUG_ON(!q->ops->buf_prepare);
 171         BUG_ON(!q->ops->buf_queue);
 172         BUG_ON(!q->ops->buf_release);
 173
 174         /* Lock is mandatory for queue_cancel to work */
 175         BUG_ON(!irqlock);
 176
 177         /* Having implementations for abstract methods are mandatory */
 178         BUG_ON(!q->int_ops);
 179
 180         mutex_init(&q->vb_lock);
 181         init_waitqueue_head(&q->wait);
 182         INIT_LIST_HEAD(&q->stream);
 183 }
 184 EXPORT_SYMBOL_GPL(videobuf_queue_core_init);
 185
 186 /* Locking: Only usage in bttv unsafe find way to remove */
 187 int videobuf_queue_is_busy(struct videobuf_queue *q)
 188 {
 189         int i;
 190
 191         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 192
 193         if (q->streaming) {
 194                 dprintk(1, "busy: streaming active\n");
 195                 return 1;
 196         }
 197         if (q->reading) {
 198                 dprintk(1, "busy: pending read #1\n");
 199                 return 1;
 200         }
 201         if (q->read_buf) {
 202                 dprintk(1, "busy: pending read #2\n");
 203                 return 1;
 204         }
 205         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 206                 if (NULL == q->bufs[i])
 207                         continue;
 208                 if (q->bufs[i]->map) {
 209                         dprintk(1, "busy: buffer #%d mapped\n", i);
 210                         return 1;
 211                 }
 212                 if (q->bufs[i]->state == VIDEOBUF_QUEUED) {
 213                         dprintk(1, "busy: buffer #%d queued\n", i);
 214                         return 1;
 215                 }
 216                 if (q->bufs[i]->state == VIDEOBUF_ACTIVE) {
 217                         dprintk(1, "busy: buffer #%d avtive\n", i);
 218                         return 1;
 219                 }
 220         }
 221         return 0;
 222 }
 223 EXPORT_SYMBOL_GPL(videobuf_queue_is_busy);
 224
 225 /**
 226  * __videobuf_free() - free all the buffers and their control structures
 227  *
 228  * This function can only be called if streaming/reading is off, i.e. no buffers
 229  * are under control of the driver.
 230  */
 231 /* Locking: Caller holds q->vb_lock */
 232 static int __videobuf_free(struct videobuf_queue *q)
 233 {
 234         int i;
 235
 236         dprintk(1, "%s\n", __func__);
 237         if (!q)
 238                 return 0;
 239
 240         if (q->streaming || q->reading) {
 241                 dprintk(1, "Cannot free buffers when streaming or reading\n");
 242                 return -EBUSY;
 243         }
 244
 245         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 246
 247         for (i = 0; i < VIDEO_MAX_FRAME; i++)
 248                 if (q->bufs[i] && q->bufs[i]->map) {
 249                         dprintk(1, "Cannot free mmapped buffers\n");
 250                         return -EBUSY;
 251                 }
 252
 253         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 254                 if (NULL == q->bufs[i])
 255                         continue;
 256                 q->ops->buf_release(q, q->bufs[i]);
 257                 kfree(q->bufs[i]);
 258                 q->bufs[i] = NULL;
 259         }
 260
 261         return 0;
 262 }
 263
 264 /* Locking: Caller holds q->vb_lock */
 265 void videobuf_queue_cancel(struct videobuf_queue *q)
 266 {
 267         unsigned long flags = 0;
 268         int i;
 269
 270         q->streaming = 0;
 271         q->reading  = 0;
 272         wake_up_interruptible_sync(&q->wait);
 273
 274         /* remove queued buffers from list */
 275         spin_lock_irqsave(q->irqlock, flags);
 276         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 277                 if (NULL == q->bufs[i])
 278                         continue;
 279                 if (q->bufs[i]->state == VIDEOBUF_QUEUED) {
 280                         list_del(&q->bufs[i]->queue);
 281                         q->bufs[i]->state = VIDEOBUF_ERROR;
 282                         wake_up_all(&q->bufs[i]->done);
 283                 }
 284         }
 285         spin_unlock_irqrestore(q->irqlock, flags);
 286
 287         /* free all buffers + clear queue */
 288         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 289                 if (NULL == q->bufs[i])
 290                         continue;
 291                 q->ops->buf_release(q, q->bufs[i]);
 292         }
 293         INIT_LIST_HEAD(&q->stream);
 294 }
 295 EXPORT_SYMBOL_GPL(videobuf_queue_cancel);
 296
 297 /* --------------------------------------------------------------------- */
 298
 299 /* Locking: Caller holds q->vb_lock */
 300 enum v4l2_field videobuf_next_field(struct videobuf_queue *q)
 301 {
 302         enum v4l2_field field = q->field;
 303
 304         BUG_ON(V4L2_FIELD_ANY == field);
 305
 306         if (V4L2_FIELD_ALTERNATE == field) {
 307                 if (V4L2_FIELD_TOP == q->last) {
 308                         field   = V4L2_FIELD_BOTTOM;
 309                         q->last = V4L2_FIELD_BOTTOM;
 310                 } else {
 311                         field   = V4L2_FIELD_TOP;
 312                         q->last = V4L2_FIELD_TOP;
 313                 }
 314         }
 315         return field;
 316 }
 317 EXPORT_SYMBOL_GPL(videobuf_next_field);
 318
 319 /* Locking: Caller holds q->vb_lock */
 320 static void videobuf_status(struct videobuf_queue *q, struct v4l2_buffer *b,
 321                             struct videobuf_buffer *vb, enum v4l2_buf_type type)
 322 {
 323         MAGIC_CHECK(vb->magic, MAGIC_BUFFER);
 324         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 325
 326         b->index    = vb->i;
 327         b->type     = type;
 328
 329         b->memory   = vb->memory;
 330         switch (b->memory) {
 331         case V4L2_MEMORY_MMAP:
 332                 b->m.offset  = vb->boff;
 333                 b->length    = vb->bsize;
 334                 break;
 335         case V4L2_MEMORY_USERPTR:
 336                 b->m.userptr = vb->baddr;
 337                 b->length    = vb->bsize;
 338                 break;
 339         case V4L2_MEMORY_OVERLAY:
 340                 b->m.offset  = vb->boff;
 341                 break;
 342         case V4L2_MEMORY_DMABUF:
 343                 /* DMABUF is not handled in videobuf framework */
 344                 break;
 345         }
 346
 347         b->flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
 348         if (vb->map)
 349                 b->flags |= V4L2_BUF_FLAG_MAPPED;
 350
 351         switch (vb->state) {
 352         case VIDEOBUF_PREPARED:
 353         case VIDEOBUF_QUEUED:
 354         case VIDEOBUF_ACTIVE:
 355                 b->flags |= V4L2_BUF_FLAG_QUEUED;
 356                 break;
 357         case VIDEOBUF_ERROR:
 358                 b->flags |= V4L2_BUF_FLAG_ERROR;
 359                 /* fall through */
 360         case VIDEOBUF_DONE:
 361                 b->flags |= V4L2_BUF_FLAG_DONE;
 362                 break;
 363         case VIDEOBUF_NEEDS_INIT:
 364         case VIDEOBUF_IDLE:
 365                 /* nothing */
 366                 break;
 367         }
 368
 369         b->field     = vb->field;
 370         b->timestamp = vb->ts;
 371         b->bytesused = vb->size;
 372         b->sequence  = vb->field_count >> 1;
 373 }
 374
 375 int videobuf_mmap_free(struct videobuf_queue *q)
 376 {
 377         int ret;
 378         videobuf_queue_lock(q);
 379         ret = __videobuf_free(q);
 380         videobuf_queue_unlock(q);
 381         return ret;
 382 }
 383 EXPORT_SYMBOL_GPL(videobuf_mmap_free);
 384
 385 /* Locking: Caller holds q->vb_lock */
 386 int __videobuf_mmap_setup(struct videobuf_queue *q,
 387                         unsigned int bcount, unsigned int bsize,
 388                         enum v4l2_memory memory)
 389 {
 390         unsigned int i;
 391         int err;
 392
 393         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 394
 395         err = __videobuf_free(q);
 396         if (0 != err)
 397                 return err;
 398
 399         /* Allocate and initialize buffers */
 400         for (i = 0; i < bcount; i++) {
 401                 q->bufs[i] = videobuf_alloc_vb(q);
 402
 403                 if (NULL == q->bufs[i])
 404                         break;
 405
 406                 q->bufs[i]->i      = i;
 407                 q->bufs[i]->memory = memory;
 408                 q->bufs[i]->bsize  = bsize;
 409                 switch (memory) {
 410                 case V4L2_MEMORY_MMAP:
 411                         q->bufs[i]->boff = PAGE_ALIGN(bsize) * i;
 412                         break;
 413                 case V4L2_MEMORY_USERPTR:
 414                 case V4L2_MEMORY_OVERLAY:
 415                 case V4L2_MEMORY_DMABUF:
 416                         /* nothing */
 417                         break;
 418                 }
 419         }
 420
 421         if (!i)
 422                 return -ENOMEM;
 423
 424         dprintk(1, "mmap setup: %d buffers, %d bytes each\n", i, bsize);
 425
 426         return i;
 427 }
 428 EXPORT_SYMBOL_GPL(__videobuf_mmap_setup);
 429
 430 int videobuf_mmap_setup(struct videobuf_queue *q,
 431                         unsigned int bcount, unsigned int bsize,
 432                         enum v4l2_memory memory)
 433 {
 434         int ret;
 435         videobuf_queue_lock(q);
 436         ret = __videobuf_mmap_setup(q, bcount, bsize, memory);
 437         videobuf_queue_unlock(q);
 438         return ret;
 439 }
 440 EXPORT_SYMBOL_GPL(videobuf_mmap_setup);
 441
 442 int videobuf_reqbufs(struct videobuf_queue *q,
 443                  struct v4l2_requestbuffers *req)
 444 {
 445         unsigned int size, count;
 446         int retval;
 447
 448         if (req->memory != V4L2_MEMORY_MMAP     &&
 449             req->memory != V4L2_MEMORY_USERPTR  &&
 450             req->memory != V4L2_MEMORY_OVERLAY) {
 451                 dprintk(1, "reqbufs: memory type invalid\n");
 452                 return -EINVAL;
 453         }
 454
 455         videobuf_queue_lock(q);
 456         if (req->type != q->type) {
 457                 dprintk(1, "reqbufs: queue type invalid\n");
 458                 retval = -EINVAL;
 459                 goto done;
 460         }
 461
 462         if (q->streaming) {
 463                 dprintk(1, "reqbufs: streaming already exists\n");
 464                 retval = -EBUSY;
 465                 goto done;
 466         }
 467         if (!list_empty(&q->stream)) {
 468                 dprintk(1, "reqbufs: stream running\n");
 469                 retval = -EBUSY;
 470                 goto done;
 471         }
 472
 473         if (req->count == 0) {
 474                 dprintk(1, "reqbufs: count invalid (%d)\n", req->count);
 475                 retval = __videobuf_free(q);
 476                 goto done;
 477         }
 478
 479         count = req->count;
 480         if (count > VIDEO_MAX_FRAME)
 481                 count = VIDEO_MAX_FRAME;
 482         size = 0;
 483         q->ops->buf_setup(q, &count, &size);
 484         dprintk(1, "reqbufs: bufs=%d, size=0x%x [%u pages total]\n",
 485                 count, size,
 486                 (unsigned int)((count * PAGE_ALIGN(size)) >> PAGE_SHIFT));
 487
 488         retval = __videobuf_mmap_setup(q, count, size, req->memory);
 489         if (retval < 0) {
 490                 dprintk(1, "reqbufs: mmap setup returned %d\n", retval);
 491                 goto done;
 492         }
 493
 494         req->count = retval;
 495         retval = 0;
 496
 497  done:
 498         videobuf_queue_unlock(q);
 499         return retval;
 500 }
 501 EXPORT_SYMBOL_GPL(videobuf_reqbufs);
 502
 503 int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b)
 504 {
 505         int ret = -EINVAL;
 506
 507         videobuf_queue_lock(q);
 508         if (unlikely(b->type != q->type)) {
 509                 dprintk(1, "querybuf: Wrong type.\n");
 510                 goto done;
 511         }
 512         if (unlikely(b->index >= VIDEO_MAX_FRAME)) {
 513                 dprintk(1, "querybuf: index out of range.\n");
 514                 goto done;
 515         }
 516         if (unlikely(NULL == q->bufs[b->index])) {
 517                 dprintk(1, "querybuf: buffer is null.\n");
 518                 goto done;
 519         }
 520
 521         videobuf_status(q, b, q->bufs[b->index], q->type);
 522
 523         ret = 0;
 524 done:
 525         videobuf_queue_unlock(q);
 526         return ret;
 527 }
 528 EXPORT_SYMBOL_GPL(videobuf_querybuf);
 529
 530 int videobuf_qbuf(struct videobuf_queue *q, struct v4l2_buffer *b)
 531 {
 532         struct videobuf_buffer *buf;
 533         enum v4l2_field field;
 534         unsigned long flags = 0;
 535         int retval;
 536
 537         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 538
 539         if (b->memory == V4L2_MEMORY_MMAP)
 540                 down_read(&current->mm->mmap_sem);
 541
 542         videobuf_queue_lock(q);
 543         retval = -EBUSY;
 544         if (q->reading) {
 545                 dprintk(1, "qbuf: Reading running...\n");
 546                 goto done;
 547         }
 548         retval = -EINVAL;
 549         if (b->type != q->type) {
 550                 dprintk(1, "qbuf: Wrong type.\n");
 551                 goto done;
 552         }
 553         if (b->index >= VIDEO_MAX_FRAME) {
 554                 dprintk(1, "qbuf: index out of range.\n");
 555                 goto done;
 556         }
 557         buf = q->bufs[b->index];
 558         if (NULL == buf) {
 559                 dprintk(1, "qbuf: buffer is null.\n");
 560                 goto done;
 561         }
 562         MAGIC_CHECK(buf->magic, MAGIC_BUFFER);
 563         if (buf->memory != b->memory) {
 564                 dprintk(1, "qbuf: memory type is wrong.\n");
 565                 goto done;
 566         }
 567         if (buf->state != VIDEOBUF_NEEDS_INIT && buf->state != VIDEOBUF_IDLE) {
 568                 dprintk(1, "qbuf: buffer is already queued or active.\n");
 569                 goto done;
 570         }
 571
 572         switch (b->memory) {
 573         case V4L2_MEMORY_MMAP:
 574                 if (0 == buf->baddr) {
 575                         dprintk(1, "qbuf: mmap requested "
 576                                    "but buffer addr is zero!\n");
 577                         goto done;
 578                 }
 579                 if (q->type == V4L2_BUF_TYPE_VIDEO_OUTPUT
 580                     || q->type == V4L2_BUF_TYPE_VBI_OUTPUT
 581                     || q->type == V4L2_BUF_TYPE_SLICED_VBI_OUTPUT
 582                     || q->type == V4L2_BUF_TYPE_SDR_OUTPUT) {
 583                         buf->size = b->bytesused;
 584                         buf->field = b->field;
 585                         buf->ts = b->timestamp;
 586                 }
 587                 break;
 588         case V4L2_MEMORY_USERPTR:
 589                 if (b->length < buf->bsize) {
 590                         dprintk(1, "qbuf: buffer length is not enough\n");
 591                         goto done;
 592                 }
 593                 if (VIDEOBUF_NEEDS_INIT != buf->state &&
 594                     buf->baddr != b->m.userptr)
 595                         q->ops->buf_release(q, buf);
 596                 buf->baddr = b->m.userptr;
 597                 break;
 598         case V4L2_MEMORY_OVERLAY:
 599                 buf->boff = b->m.offset;
 600                 break;
 601         default:
 602                 dprintk(1, "qbuf: wrong memory type\n");
 603                 goto done;
 604         }
 605
 606         dprintk(1, "qbuf: requesting next field\n");
 607         field = videobuf_next_field(q);
 608         retval = q->ops->buf_prepare(q, buf, field);
 609         if (0 != retval) {
 610                 dprintk(1, "qbuf: buffer_prepare returned %d\n", retval);
 611                 goto done;
 612         }
 613
 614         list_add_tail(&buf->stream, &q->stream);
 615         if (q->streaming) {
 616                 spin_lock_irqsave(q->irqlock, flags);
 617                 q->ops->buf_queue(q, buf);
 618                 spin_unlock_irqrestore(q->irqlock, flags);
 619         }
 620         dprintk(1, "qbuf: succeeded\n");
 621         retval = 0;
 622         wake_up_interruptible_sync(&q->wait);
 623
 624 done:
 625         videobuf_queue_unlock(q);
 626
 627         if (b->memory == V4L2_MEMORY_MMAP)
 628                 up_read(&current->mm->mmap_sem);
 629
 630         return retval;
 631 }
 632 EXPORT_SYMBOL_GPL(videobuf_qbuf);
 633
 634 /* Locking: Caller holds q->vb_lock */
 635 static int stream_next_buffer_check_queue(struct videobuf_queue *q, int noblock)
 636 {
 637         int retval;
 638
 639 checks:
 640         if (!q->streaming) {
 641                 dprintk(1, "next_buffer: Not streaming\n");
 642                 retval = -EINVAL;
 643                 goto done;
 644         }
 645
 646         if (list_empty(&q->stream)) {
 647                 if (noblock) {
 648                         retval = -EAGAIN;
 649                         dprintk(2, "next_buffer: no buffers to dequeue\n");
 650                         goto done;
 651                 } else {
 652                         dprintk(2, "next_buffer: waiting on buffer\n");
 653
 654                         /* Drop lock to avoid deadlock with qbuf */
 655                         videobuf_queue_unlock(q);
 656
 657                         /* Checking list_empty and streaming is safe without
 658                          * locks because we goto checks to validate while
 659                          * holding locks before proceeding */
 660                         retval = wait_event_interruptible(q->wait,
 661                                 !list_empty(&q->stream) || !q->streaming);
 662                         videobuf_queue_lock(q);
 663
 664                         if (retval)
 665                                 goto done;
 666
 667                         goto checks;
 668                 }
 669         }
 670
 671         retval = 0;
 672
 673 done:
 674         return retval;
 675 }
 676
 677 /* Locking: Caller holds q->vb_lock */
 678 static int stream_next_buffer(struct videobuf_queue *q,
 679                         struct videobuf_buffer **vb, int nonblocking)
 680 {
 681         int retval;
 682         struct videobuf_buffer *buf = NULL;
 683
 684         retval = stream_next_buffer_check_queue(q, nonblocking);
 685         if (retval)
 686                 goto done;
 687
 688         buf = list_entry(q->stream.next, struct videobuf_buffer, stream);
 689         retval = videobuf_waiton(q, buf, nonblocking, 1);
 690         if (retval < 0)
 691                 goto done;
 692
 693         *vb = buf;
 694 done:
 695         return retval;
 696 }
 697
 698 int videobuf_dqbuf(struct videobuf_queue *q,
 699                    struct v4l2_buffer *b, int nonblocking)
 700 {
 701         struct videobuf_buffer *buf = NULL;
 702         int retval;
 703
 704         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 705
 706         memset(b, 0, sizeof(*b));
 707         videobuf_queue_lock(q);
 708
 709         retval = stream_next_buffer(q, &buf, nonblocking);
 710         if (retval < 0) {
 711                 dprintk(1, "dqbuf: next_buffer error: %i\n", retval);
 712                 goto done;
 713         }
 714
 715         switch (buf->state) {
 716         case VIDEOBUF_ERROR:
 717                 dprintk(1, "dqbuf: state is error\n");
 718                 break;
 719         case VIDEOBUF_DONE:
 720                 dprintk(1, "dqbuf: state is done\n");
 721                 break;
 722         default:
 723                 dprintk(1, "dqbuf: state invalid\n");
 724                 retval = -EINVAL;
 725                 goto done;
 726         }
 727         CALL(q, sync, q, buf);
 728         videobuf_status(q, b, buf, q->type);
 729         list_del(&buf->stream);
 730         buf->state = VIDEOBUF_IDLE;
 731         b->flags &= ~V4L2_BUF_FLAG_DONE;
 732 done:
 733         videobuf_queue_unlock(q);
 734         return retval;
 735 }
 736 EXPORT_SYMBOL_GPL(videobuf_dqbuf);
 737
 738 int videobuf_streamon(struct videobuf_queue *q)
 739 {
 740         struct videobuf_buffer *buf;
 741         unsigned long flags = 0;
 742         int retval;
 743
 744         videobuf_queue_lock(q);
 745         retval = -EBUSY;
 746         if (q->reading)
 747                 goto done;
 748         retval = 0;
 749         if (q->streaming)
 750                 goto done;
 751         q->streaming = 1;
 752         spin_lock_irqsave(q->irqlock, flags);
 753         list_for_each_entry(buf, &q->stream, stream)
 754                 if (buf->state == VIDEOBUF_PREPARED)
 755                         q->ops->buf_queue(q, buf);
 756         spin_unlock_irqrestore(q->irqlock, flags);
 757
 758         wake_up_interruptible_sync(&q->wait);
 759 done:
 760         videobuf_queue_unlock(q);
 761         return retval;
 762 }
 763 EXPORT_SYMBOL_GPL(videobuf_streamon);
 764
 765 /* Locking: Caller holds q->vb_lock */
 766 static int __videobuf_streamoff(struct videobuf_queue *q)
 767 {
 768         if (!q->streaming)
 769                 return -EINVAL;
 770
 771         videobuf_queue_cancel(q);
 772
 773         return 0;
 774 }
 775
 776 int videobuf_streamoff(struct videobuf_queue *q)
 777 {
 778         int retval;
 779
 780         videobuf_queue_lock(q);
 781         retval = __videobuf_streamoff(q);
 782         videobuf_queue_unlock(q);
 783
 784         return retval;
 785 }
 786 EXPORT_SYMBOL_GPL(videobuf_streamoff);
 787
 788 /* Locking: Caller holds q->vb_lock */
 789 static ssize_t videobuf_read_zerocopy(struct videobuf_queue *q,
 790                                       char __user *data,
 791                                       size_t count, loff_t *ppos)
 792 {
 793         enum v4l2_field field;
 794         unsigned long flags = 0;
 795         int retval;
 796
 797         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 798
 799         /* setup stuff */
 800         q->read_buf = videobuf_alloc_vb(q);
 801         if (NULL == q->read_buf)
 802                 return -ENOMEM;
 803
 804         q->read_buf->memory = V4L2_MEMORY_USERPTR;
 805         q->read_buf->baddr  = (unsigned long)data;
 806         q->read_buf->bsize  = count;
 807
 808         field = videobuf_next_field(q);
 809         retval = q->ops->buf_prepare(q, q->read_buf, field);
 810         if (0 != retval)
 811                 goto done;
 812
 813         /* start capture & wait */
 814         spin_lock_irqsave(q->irqlock, flags);
 815         q->ops->buf_queue(q, q->read_buf);
 816         spin_unlock_irqrestore(q->irqlock, flags);
 817         retval = videobuf_waiton(q, q->read_buf, 0, 0);
 818         if (0 == retval) {
 819                 CALL(q, sync, q, q->read_buf);
 820                 if (VIDEOBUF_ERROR == q->read_buf->state)
 821                         retval = -EIO;
 822                 else
 823                         retval = q->read_buf->size;
 824         }
 825
 826 done:
 827         /* cleanup */
 828         q->ops->buf_release(q, q->read_buf);
 829         kfree(q->read_buf);
 830         q->read_buf = NULL;
 831         return retval;
 832 }
 833
 834 static int __videobuf_copy_to_user(struct videobuf_queue *q,
 835                                    struct videobuf_buffer *buf,
 836                                    char __user *data, size_t count,
 837                                    int nonblocking)
 838 {
 839         void *vaddr = CALLPTR(q, vaddr, buf);
 840
 841         /* copy to userspace */
 842         if (count > buf->size - q->read_off)
 843                 count = buf->size - q->read_off;
 844
 845         if (copy_to_user(data, vaddr + q->read_off, count))
 846                 return -EFAULT;
 847
 848         return count;
 849 }
 850
 851 static int __videobuf_copy_stream(struct videobuf_queue *q,
 852                                   struct videobuf_buffer *buf,
 853                                   char __user *data, size_t count, size_t pos,
 854                                   int vbihack, int nonblocking)
 855 {
 856         unsigned int *fc = CALLPTR(q, vaddr, buf);
 857
 858         if (vbihack) {
 859                 /* dirty, undocumented hack -- pass the frame counter
 860                         * within the last four bytes of each vbi data block.
 861                         * We need that one to maintain backward compatibility
 862                         * to all vbi decoding software out there ... */
 863                 fc += (buf->size >> 2) - 1;
 864                 *fc = buf->field_count >> 1;
 865                 dprintk(1, "vbihack: %d\n", *fc);
 866         }
 867
 868         /* copy stuff using the common method */
 869         count = __videobuf_copy_to_user(q, buf, data, count, nonblocking);
 870
 871         if ((count == -EFAULT) && (pos == 0))
 872                 return -EFAULT;
 873
 874         return count;
 875 }
 876
 877 ssize_t videobuf_read_one(struct videobuf_queue *q,
 878                           char __user *data, size_t count, loff_t *ppos,
 879                           int nonblocking)
 880 {
 881         enum v4l2_field field;
 882         unsigned long flags = 0;
 883         unsigned size = 0, nbufs = 1;
 884         int retval;
 885
 886         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 887
 888         videobuf_queue_lock(q);
 889
 890         q->ops->buf_setup(q, &nbufs, &size);
 891
 892         if (NULL == q->read_buf  &&
 893             count >= size        &&
 894             !nonblocking) {
 895                 retval = videobuf_read_zerocopy(q, data, count, ppos);
 896                 if (retval >= 0  ||  retval == -EIO)
 897                         /* ok, all done */
 898                         goto done;
 899                 /* fallback to kernel bounce buffer on failures */
 900         }
 901
 902         if (NULL == q->read_buf) {
 903                 /* need to capture a new frame */
 904                 retval = -ENOMEM;
 905                 q->read_buf = videobuf_alloc_vb(q);
 906
 907                 dprintk(1, "video alloc=0x%p\n", q->read_buf);
 908                 if (NULL == q->read_buf)
 909                         goto done;
 910                 q->read_buf->memory = V4L2_MEMORY_USERPTR;
 911                 q->read_buf->bsize = count; /* preferred size */
 912                 field = videobuf_next_field(q);
 913                 retval = q->ops->buf_prepare(q, q->read_buf, field);
 914
 915                 if (0 != retval) {
 916                         kfree(q->read_buf);
 917                         q->read_buf = NULL;
 918                         goto done;
 919                 }
 920
 921                 spin_lock_irqsave(q->irqlock, flags);
 922                 q->ops->buf_queue(q, q->read_buf);
 923                 spin_unlock_irqrestore(q->irqlock, flags);
 924
 925                 q->read_off = 0;
 926         }
 927
 928         /* wait until capture is done */
 929         retval = videobuf_waiton(q, q->read_buf, nonblocking, 1);
 930         if (0 != retval)
 931                 goto done;
 932
 933         CALL(q, sync, q, q->read_buf);
 934
 935         if (VIDEOBUF_ERROR == q->read_buf->state) {
 936                 /* catch I/O errors */
 937                 q->ops->buf_release(q, q->read_buf);
 938                 kfree(q->read_buf);
 939                 q->read_buf = NULL;
 940                 retval = -EIO;
 941                 goto done;
 942         }
 943
 944         /* Copy to userspace */
 945         retval = __videobuf_copy_to_user(q, q->read_buf, data, count, nonblocking);
 946         if (retval < 0)
 947                 goto done;
 948
 949         q->read_off += retval;
 950         if (q->read_off == q->read_buf->size) {
 951                 /* all data copied, cleanup */
 952                 q->ops->buf_release(q, q->read_buf);
 953                 kfree(q->read_buf);
 954                 q->read_buf = NULL;
 955         }
 956
 957 done:
 958         videobuf_queue_unlock(q);
 959         return retval;
 960 }
 961 EXPORT_SYMBOL_GPL(videobuf_read_one);
 962
 963 /* Locking: Caller holds q->vb_lock */
 964 static int __videobuf_read_start(struct videobuf_queue *q)
 965 {
 966         enum v4l2_field field;
 967         unsigned long flags = 0;
 968         unsigned int count = 0, size = 0;
 969         int err, i;
 970
 971         q->ops->buf_setup(q, &count, &size);
 972         if (count < 2)
 973                 count = 2;
 974         if (count > VIDEO_MAX_FRAME)
 975                 count = VIDEO_MAX_FRAME;
 976         size = PAGE_ALIGN(size);
 977
 978         err = __videobuf_mmap_setup(q, count, size, V4L2_MEMORY_USERPTR);
 979         if (err < 0)
 980                 return err;
 981
 982         count = err;
 983
 984         for (i = 0; i < count; i++) {
 985                 field = videobuf_next_field(q);
 986                 err = q->ops->buf_prepare(q, q->bufs[i], field);
 987                 if (err)
 988                         return err;
 989                 list_add_tail(&q->bufs[i]->stream, &q->stream);
 990         }
 991         spin_lock_irqsave(q->irqlock, flags);
 992         for (i = 0; i < count; i++)
 993                 q->ops->buf_queue(q, q->bufs[i]);
 994         spin_unlock_irqrestore(q->irqlock, flags);
 995         q->reading = 1;
 996         return 0;
 997 }
 998
 999 static void __videobuf_read_stop(struct videobuf_queue *q)
1000 {
1001         int i;
1002
1003         videobuf_queue_cancel(q);
1004         __videobuf_free(q);
1005         INIT_LIST_HEAD(&q->stream);
1006         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
1007                 if (NULL == q->bufs[i])
1008                         continue;
1009                 kfree(q->bufs[i]);
1010                 q->bufs[i] = NULL;
1011         }
1012         q->read_buf = NULL;
1013 }
1014
1015 int videobuf_read_start(struct videobuf_queue *q)
1016 {
1017         int rc;
1018
1019         videobuf_queue_lock(q);
1020         rc = __videobuf_read_start(q);
1021         videobuf_queue_unlock(q);
1022
1023         return rc;
1024 }
1025 EXPORT_SYMBOL_GPL(videobuf_read_start);
1026
1027 void videobuf_read_stop(struct videobuf_queue *q)
1028 {
1029         videobuf_queue_lock(q);
1030         __videobuf_read_stop(q);
1031         videobuf_queue_unlock(q);
1032 }
1033 EXPORT_SYMBOL_GPL(videobuf_read_stop);
1034
1035 void videobuf_stop(struct videobuf_queue *q)
1036 {
1037         videobuf_queue_lock(q);
1038
1039         if (q->streaming)
1040                 __videobuf_streamoff(q);
1041
1042         if (q->reading)
1043                 __videobuf_read_stop(q);
1044
1045         videobuf_queue_unlock(q);
1046 }
1047 EXPORT_SYMBOL_GPL(videobuf_stop);
1048
1049 ssize_t videobuf_read_stream(struct videobuf_queue *q,
1050                              char __user *data, size_t count, loff_t *ppos,
1051                              int vbihack, int nonblocking)
1052 {
1053         int rc, retval;
1054         unsigned long flags = 0;
1055
1056         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
1057
1058         dprintk(2, "%s\n", __func__);
1059         videobuf_queue_lock(q);
1060         retval = -EBUSY;
1061         if (q->streaming)
1062                 goto done;
1063         if (!q->reading) {
1064                 retval = __videobuf_read_start(q);
1065                 if (retval < 0)
1066                         goto done;
1067         }
1068
1069         retval = 0;
1070         while (count > 0) {
1071                 /* get / wait for data */
1072                 if (NULL == q->read_buf) {
1073                         q->read_buf = list_entry(q->stream.next,
1074                                                  struct videobuf_buffer,
1075                                                  stream);
1076                         list_del(&q->read_buf->stream);
1077                         q->read_off = 0;
1078                 }
1079                 rc = videobuf_waiton(q, q->read_buf, nonblocking, 1);
1080                 if (rc < 0) {
1081                         if (0 == retval)
1082                                 retval = rc;
1083                         break;
1084                 }
1085
1086                 if (q->read_buf->state == VIDEOBUF_DONE) {
1087                         rc = __videobuf_copy_stream(q, q->read_buf, data + retval, count,
1088                                         retval, vbihack, nonblocking);
1089                         if (rc < 0) {
1090                                 retval = rc;
1091                                 break;
1092                         }
1093                         retval      += rc;
1094                         count       -= rc;
1095                         q->read_off += rc;
1096                 } else {
1097                         /* some error */
1098                         q->read_off = q->read_buf->size;
1099                         if (0 == retval)
1100                                 retval = -EIO;
1101                 }
1102
1103                 /* requeue buffer when done with copying */
1104                 if (q->read_off == q->read_buf->size) {
1105                         list_add_tail(&q->read_buf->stream,
1106                                       &q->stream);
1107                         spin_lock_irqsave(q->irqlock, flags);
1108                         q->ops->buf_queue(q, q->read_buf);
1109                         spin_unlock_irqrestore(q->irqlock, flags);
1110                         q->read_buf = NULL;
1111                 }
1112                 if (retval < 0)
1113                         break;
1114         }
1115
1116 done:
1117         videobuf_queue_unlock(q);
1118         return retval;
1119 }
1120 EXPORT_SYMBOL_GPL(videobuf_read_stream);
1121
1122 unsigned int videobuf_poll_stream(struct file *file,
1123                                   struct videobuf_queue *q,
1124                                   poll_table *wait)
1125 {
1126         unsigned long req_events = poll_requested_events(wait);
1127         struct videobuf_buffer *buf = NULL;
1128         unsigned int rc = 0;
1129
1130         videobuf_queue_lock(q);
1131         if (q->streaming) {
1132                 if (!list_empty(&q->stream))
1133                         buf = list_entry(q->stream.next,
1134                                          struct videobuf_buffer, stream);
1135         } else if (req_events & (POLLIN | POLLRDNORM)) {
1136                 if (!q->reading)
1137                         __videobuf_read_start(q);
1138                 if (!q->reading) {
1139                         rc = POLLERR;
1140                 } else if (NULL == q->read_buf) {
1141                         q->read_buf = list_entry(q->stream.next,
1142                                                  struct videobuf_buffer,
1143                                                  stream);
1144                         list_del(&q->read_buf->stream);
1145                         q->read_off = 0;
1146                 }
1147                 buf = q->read_buf;
1148         }
1149         if (!buf)
1150                 rc = POLLERR;
1151
1152         if (0 == rc) {
1153                 poll_wait(file, &buf->done, wait);
1154                 if (buf->state == VIDEOBUF_DONE ||
1155                     buf->state == VIDEOBUF_ERROR) {
1156                         switch (q->type) {
1157                         case V4L2_BUF_TYPE_VIDEO_OUTPUT:
1158                         case V4L2_BUF_TYPE_VBI_OUTPUT:
1159                         case V4L2_BUF_TYPE_SLICED_VBI_OUTPUT:
1160                         case V4L2_BUF_TYPE_SDR_OUTPUT:
1161                                 rc = POLLOUT | POLLWRNORM;
1162                                 break;
1163                         default:
1164                                 rc = POLLIN | POLLRDNORM;
1165                                 break;
1166                         }
1167                 }
1168         }
1169         videobuf_queue_unlock(q);
1170         return rc;
1171 }
1172 EXPORT_SYMBOL_GPL(videobuf_poll_stream);
1173
1174 int videobuf_mmap_mapper(struct videobuf_queue *q, struct vm_area_struct *vma)
1175 {
1176         int rc = -EINVAL;
1177         int i;
1178
1179         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
1180
1181         if (!(vma->vm_flags & VM_WRITE) || !(vma->vm_flags & VM_SHARED)) {
1182                 dprintk(1, "mmap appl bug: PROT_WRITE and MAP_SHARED are required\n");
1183                 return -EINVAL;
1184         }
1185
1186         videobuf_queue_lock(q);
1187         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
1188                 struct videobuf_buffer *buf = q->bufs[i];
1189
1190                 if (buf && buf->memory == V4L2_MEMORY_MMAP &&
1191                                 buf->boff == (vma->vm_pgoff << PAGE_SHIFT)) {
1192                         rc = CALL(q, mmap_mapper, q, buf, vma);
1193                         break;
1194                 }
1195         }
1196         videobuf_queue_unlock(q);
1197
1198         return rc;
1199 }
1200 EXPORT_SYMBOL_GPL(videobuf_mmap_mapper);