drivers/media/video/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/slab.h>
  20 #include <linux/interrupt.h>
  21
  22 #include <media/videobuf-core.h>
  23
  24 #define MAGIC_BUFFER 0x20070728
  25 #define MAGIC_CHECK(is, should) do {                                       \
  26         if (unlikely((is) != (should))) {                                  \
  27         printk(KERN_ERR "magic mismatch: %x (expected %x)\n", is, should); \
  28         BUG(); } } while (0)
  29
  30 static int debug;
  31 module_param(debug, int, 0644);
  32
  33 MODULE_DESCRIPTION("helper module to manage video4linux buffers");
  34 MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@infradead.org>");
  35 MODULE_LICENSE("GPL");
  36
  37 #define dprintk(level, fmt, arg...) do {                        \
  38         if (debug >= level)                                     \
  39         printk(KERN_DEBUG "vbuf: " fmt , ## arg); } while (0)
  40
  41 /* --------------------------------------------------------------------- */
  42
  43 #define CALL(q, f, arg...)                                              \
  44         ((q->int_ops->f) ? q->int_ops->f(arg) : 0)
  45
  46 void *videobuf_alloc(struct videobuf_queue *q)
  47 {
  48         struct videobuf_buffer *vb;
  49
  50         BUG_ON(q->msize < sizeof(*vb));
  51
  52         if (!q->int_ops || !q->int_ops->alloc) {
  53                 printk(KERN_ERR "No specific ops defined!\n");
  54                 BUG();
  55         }
  56
  57         vb = q->int_ops->alloc(q->msize);
  58
  59         if (NULL != vb) {
  60                 init_waitqueue_head(&vb->done);
  61                 vb->magic     = MAGIC_BUFFER;
  62         }
  63
  64         return vb;
  65 }
  66
  67 #define WAITON_CONDITION (vb->state != VIDEOBUF_ACTIVE &&\
  68                                 vb->state != VIDEOBUF_QUEUED)
  69 int videobuf_waiton(struct videobuf_buffer *vb, int non_blocking, int intr)
  70 {
  71         MAGIC_CHECK(vb->magic, MAGIC_BUFFER);
  72
  73         if (non_blocking) {
  74                 if (WAITON_CONDITION)
  75                         return 0;
  76                 else
  77                         return -EAGAIN;
  78         }
  79
  80         if (intr)
  81                 return wait_event_interruptible(vb->done, WAITON_CONDITION);
  82         else
  83                 wait_event(vb->done, WAITON_CONDITION);
  84
  85         return 0;
  86 }
  87
  88 int videobuf_iolock(struct videobuf_queue *q, struct videobuf_buffer *vb,
  89                     struct v4l2_framebuffer *fbuf)
  90 {
  91         MAGIC_CHECK(vb->magic, MAGIC_BUFFER);
  92         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
  93
  94         return CALL(q, iolock, q, vb, fbuf);
  95 }
  96
  97 void *videobuf_queue_to_vmalloc (struct videobuf_queue *q,
  98                            struct videobuf_buffer *buf)
  99 {
 100         return CALL(q, vmalloc, buf);
 101 }
 102 EXPORT_SYMBOL_GPL(videobuf_queue_to_vmalloc);
 103
 104 /* --------------------------------------------------------------------- */
 105
 106
 107 void videobuf_queue_core_init(struct videobuf_queue *q,
 108                          struct videobuf_queue_ops *ops,
 109                          struct device *dev,
 110                          spinlock_t *irqlock,
 111                          enum v4l2_buf_type type,
 112                          enum v4l2_field field,
 113                          unsigned int msize,
 114                          void *priv,
 115                          struct videobuf_qtype_ops *int_ops)
 116 {
 117         memset(q, 0, sizeof(*q));
 118         q->irqlock   = irqlock;
 119         q->dev       = dev;
 120         q->type      = type;
 121         q->field     = field;
 122         q->msize     = msize;
 123         q->ops       = ops;
 124         q->priv_data = priv;
 125         q->int_ops   = int_ops;
 126
 127         /* All buffer operations are mandatory */
 128         BUG_ON(!q->ops->buf_setup);
 129         BUG_ON(!q->ops->buf_prepare);
 130         BUG_ON(!q->ops->buf_queue);
 131         BUG_ON(!q->ops->buf_release);
 132
 133         /* Lock is mandatory for queue_cancel to work */
 134         BUG_ON(!irqlock);
 135
 136         /* Having implementations for abstract methods are mandatory */
 137         BUG_ON(!q->int_ops);
 138
 139         mutex_init(&q->vb_lock);
 140         init_waitqueue_head(&q->wait);
 141         INIT_LIST_HEAD(&q->stream);
 142 }
 143
 144 /* Locking: Only usage in bttv unsafe find way to remove */
 145 int videobuf_queue_is_busy(struct videobuf_queue *q)
 146 {
 147         int i;
 148
 149         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 150
 151         if (q->streaming) {
 152                 dprintk(1, "busy: streaming active\n");
 153                 return 1;
 154         }
 155         if (q->reading) {
 156                 dprintk(1, "busy: pending read #1\n");
 157                 return 1;
 158         }
 159         if (q->read_buf) {
 160                 dprintk(1, "busy: pending read #2\n");
 161                 return 1;
 162         }
 163         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 164                 if (NULL == q->bufs[i])
 165                         continue;
 166                 if (q->bufs[i]->map) {
 167                         dprintk(1, "busy: buffer #%d mapped\n", i);
 168                         return 1;
 169                 }
 170                 if (q->bufs[i]->state == VIDEOBUF_QUEUED) {
 171                         dprintk(1, "busy: buffer #%d queued\n", i);
 172                         return 1;
 173                 }
 174                 if (q->bufs[i]->state == VIDEOBUF_ACTIVE) {
 175                         dprintk(1, "busy: buffer #%d avtive\n", i);
 176                         return 1;
 177                 }
 178         }
 179         return 0;
 180 }
 181
 182 /* Locking: Caller holds q->vb_lock */
 183 void videobuf_queue_cancel(struct videobuf_queue *q)
 184 {
 185         unsigned long flags = 0;
 186         int i;
 187
 188         q->streaming = 0;
 189         q->reading  = 0;
 190         wake_up_interruptible_sync(&q->wait);
 191
 192         /* remove queued buffers from list */
 193         spin_lock_irqsave(q->irqlock, flags);
 194         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 195                 if (NULL == q->bufs[i])
 196                         continue;
 197                 if (q->bufs[i]->state == VIDEOBUF_QUEUED) {
 198                         list_del(&q->bufs[i]->queue);
 199                         q->bufs[i]->state = VIDEOBUF_ERROR;
 200                         wake_up_all(&q->bufs[i]->done);
 201                 }
 202         }
 203         spin_unlock_irqrestore(q->irqlock, flags);
 204
 205         /* free all buffers + clear queue */
 206         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 207                 if (NULL == q->bufs[i])
 208                         continue;
 209                 q->ops->buf_release(q, q->bufs[i]);
 210         }
 211         INIT_LIST_HEAD(&q->stream);
 212 }
 213
 214 /* --------------------------------------------------------------------- */
 215
 216 /* Locking: Caller holds q->vb_lock */
 217 enum v4l2_field videobuf_next_field(struct videobuf_queue *q)
 218 {
 219         enum v4l2_field field = q->field;
 220
 221         BUG_ON(V4L2_FIELD_ANY == field);
 222
 223         if (V4L2_FIELD_ALTERNATE == field) {
 224                 if (V4L2_FIELD_TOP == q->last) {
 225                         field   = V4L2_FIELD_BOTTOM;
 226                         q->last = V4L2_FIELD_BOTTOM;
 227                 } else {
 228                         field   = V4L2_FIELD_TOP;
 229                         q->last = V4L2_FIELD_TOP;
 230                 }
 231         }
 232         return field;
 233 }
 234
 235 /* Locking: Caller holds q->vb_lock */
 236 static void videobuf_status(struct videobuf_queue *q, struct v4l2_buffer *b,
 237                             struct videobuf_buffer *vb, enum v4l2_buf_type type)
 238 {
 239         MAGIC_CHECK(vb->magic, MAGIC_BUFFER);
 240         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 241
 242         b->index    = vb->i;
 243         b->type     = type;
 244
 245         b->memory   = vb->memory;
 246         switch (b->memory) {
 247         case V4L2_MEMORY_MMAP:
 248                 b->m.offset  = vb->boff;
 249                 b->length    = vb->bsize;
 250                 break;
 251         case V4L2_MEMORY_USERPTR:
 252                 b->m.userptr = vb->baddr;
 253                 b->length    = vb->bsize;
 254                 break;
 255         case V4L2_MEMORY_OVERLAY:
 256                 b->m.offset  = vb->boff;
 257                 break;
 258         }
 259
 260         b->flags    = 0;
 261         if (vb->map)
 262                 b->flags |= V4L2_BUF_FLAG_MAPPED;
 263
 264         switch (vb->state) {
 265         case VIDEOBUF_PREPARED:
 266         case VIDEOBUF_QUEUED:
 267         case VIDEOBUF_ACTIVE:
 268                 b->flags |= V4L2_BUF_FLAG_QUEUED;
 269                 break;
 270         case VIDEOBUF_DONE:
 271         case VIDEOBUF_ERROR:
 272                 b->flags |= V4L2_BUF_FLAG_DONE;
 273                 break;
 274         case VIDEOBUF_NEEDS_INIT:
 275         case VIDEOBUF_IDLE:
 276                 /* nothing */
 277                 break;
 278         }
 279
 280         if (vb->input != UNSET) {
 281                 b->flags |= V4L2_BUF_FLAG_INPUT;
 282                 b->input  = vb->input;
 283         }
 284
 285         b->field     = vb->field;
 286         b->timestamp = vb->ts;
 287         b->bytesused = vb->size;
 288         b->sequence  = vb->field_count >> 1;
 289 }
 290
 291 /* Locking: Caller holds q->vb_lock */
 292 static int __videobuf_mmap_free(struct videobuf_queue *q)
 293 {
 294         int i;
 295         int rc;
 296
 297         if (!q)
 298                 return 0;
 299
 300         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 301
 302
 303         rc  = CALL(q, mmap_free, q);
 304
 305         q->is_mmapped = 0;
 306
 307         if (rc < 0)
 308                 return rc;
 309
 310         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 311                 if (NULL == q->bufs[i])
 312                         continue;
 313                 q->ops->buf_release(q, q->bufs[i]);
 314                 kfree(q->bufs[i]);
 315                 q->bufs[i] = NULL;
 316         }
 317
 318         return rc;
 319 }
 320
 321 int videobuf_mmap_free(struct videobuf_queue *q)
 322 {
 323         int ret;
 324         mutex_lock(&q->vb_lock);
 325         ret = __videobuf_mmap_free(q);
 326         mutex_unlock(&q->vb_lock);
 327         return ret;
 328 }
 329
 330 /* Locking: Caller holds q->vb_lock */
 331 static int __videobuf_mmap_setup(struct videobuf_queue *q,
 332                         unsigned int bcount, unsigned int bsize,
 333                         enum v4l2_memory memory)
 334 {
 335         unsigned int i;
 336         int err;
 337
 338         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 339
 340         err = __videobuf_mmap_free(q);
 341         if (0 != err)
 342                 return err;
 343
 344         /* Allocate and initialize buffers */
 345         for (i = 0; i < bcount; i++) {
 346                 q->bufs[i] = videobuf_alloc(q);
 347
 348                 if (q->bufs[i] == NULL)
 349                         break;
 350
 351                 q->bufs[i]->i      = i;
 352                 q->bufs[i]->input  = UNSET;
 353                 q->bufs[i]->memory = memory;
 354                 q->bufs[i]->bsize  = bsize;
 355                 switch (memory) {
 356                 case V4L2_MEMORY_MMAP:
 357                         q->bufs[i]->boff  = bsize * i;
 358                         break;
 359                 case V4L2_MEMORY_USERPTR:
 360                 case V4L2_MEMORY_OVERLAY:
 361                         /* nothing */
 362                         break;
 363                 }
 364         }
 365
 366         if (!i)
 367                 return -ENOMEM;
 368
 369         dprintk(1, "mmap setup: %d buffers, %d bytes each\n",
 370                 i, bsize);
 371
 372         return i;
 373 }
 374
 375 int videobuf_mmap_setup(struct videobuf_queue *q,
 376                         unsigned int bcount, unsigned int bsize,
 377                         enum v4l2_memory memory)
 378 {
 379         int ret;
 380         mutex_lock(&q->vb_lock);
 381         ret = __videobuf_mmap_setup(q, bcount, bsize, memory);
 382         mutex_unlock(&q->vb_lock);
 383         return ret;
 384 }
 385
 386 int videobuf_reqbufs(struct videobuf_queue *q,
 387                  struct v4l2_requestbuffers *req)
 388 {
 389         unsigned int size, count;
 390         int retval;
 391
 392         if (req->count < 1) {
 393                 dprintk(1, "reqbufs: count invalid (%d)\n", req->count);
 394                 return -EINVAL;
 395         }
 396
 397         if (req->memory != V4L2_MEMORY_MMAP     &&
 398             req->memory != V4L2_MEMORY_USERPTR  &&
 399             req->memory != V4L2_MEMORY_OVERLAY) {
 400                 dprintk(1, "reqbufs: memory type invalid\n");
 401                 return -EINVAL;
 402         }
 403
 404         mutex_lock(&q->vb_lock);
 405         if (req->type != q->type) {
 406                 dprintk(1, "reqbufs: queue type invalid\n");
 407                 retval = -EINVAL;
 408                 goto done;
 409         }
 410
 411         if (q->streaming) {
 412                 dprintk(1, "reqbufs: streaming already exists\n");
 413                 retval = -EBUSY;
 414                 goto done;
 415         }
 416         if (!list_empty(&q->stream)) {
 417                 dprintk(1, "reqbufs: stream running\n");
 418                 retval = -EBUSY;
 419                 goto done;
 420         }
 421
 422         count = req->count;
 423         if (count > VIDEO_MAX_FRAME)
 424                 count = VIDEO_MAX_FRAME;
 425         size = 0;
 426         q->ops->buf_setup(q, &count, &size);
 427         size = PAGE_ALIGN(size);
 428         dprintk(1, "reqbufs: bufs=%d, size=0x%x [%d pages total]\n",
 429                 count, size, (count*size)>>PAGE_SHIFT);
 430
 431         retval = __videobuf_mmap_setup(q, count, size, req->memory);
 432         if (retval < 0) {
 433                 dprintk(1, "reqbufs: mmap setup returned %d\n", retval);
 434                 goto done;
 435         }
 436
 437         req->count = retval;
 438
 439  done:
 440         mutex_unlock(&q->vb_lock);
 441         return retval;
 442 }
 443
 444 int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b)
 445 {
 446         int ret = -EINVAL;
 447
 448         mutex_lock(&q->vb_lock);
 449         if (unlikely(b->type != q->type)) {
 450                 dprintk(1, "querybuf: Wrong type.\n");
 451                 goto done;
 452         }
 453         if (unlikely(b->index < 0 || b->index >= VIDEO_MAX_FRAME)) {
 454                 dprintk(1, "querybuf: index out of range.\n");
 455                 goto done;
 456         }
 457         if (unlikely(NULL == q->bufs[b->index])) {
 458                 dprintk(1, "querybuf: buffer is null.\n");
 459                 goto done;
 460         }
 461
 462         videobuf_status(q, b, q->bufs[b->index], q->type);
 463
 464         ret = 0;
 465 done:
 466         mutex_unlock(&q->vb_lock);
 467         return ret;
 468 }
 469
 470 int videobuf_qbuf(struct videobuf_queue *q,
 471               struct v4l2_buffer *b)
 472 {
 473         struct videobuf_buffer *buf;
 474         enum v4l2_field field;
 475         unsigned long flags = 0;
 476         int retval;
 477
 478         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 479
 480         if (b->memory == V4L2_MEMORY_MMAP)
 481                 down_read(&current->mm->mmap_sem);
 482
 483         mutex_lock(&q->vb_lock);
 484         retval = -EBUSY;
 485         if (q->reading) {
 486                 dprintk(1, "qbuf: Reading running...\n");
 487                 goto done;
 488         }
 489         retval = -EINVAL;
 490         if (b->type != q->type) {
 491                 dprintk(1, "qbuf: Wrong type.\n");
 492                 goto done;
 493         }
 494         if (b->index < 0 || b->index >= VIDEO_MAX_FRAME) {
 495                 dprintk(1, "qbuf: index out of range.\n");
 496                 goto done;
 497         }
 498         buf = q->bufs[b->index];
 499         if (NULL == buf) {
 500                 dprintk(1, "qbuf: buffer is null.\n");
 501                 goto done;
 502         }
 503         MAGIC_CHECK(buf->magic, MAGIC_BUFFER);
 504         if (buf->memory != b->memory) {
 505                 dprintk(1, "qbuf: memory type is wrong.\n");
 506                 goto done;
 507         }
 508         if (buf->state != VIDEOBUF_NEEDS_INIT && buf->state != VIDEOBUF_IDLE) {
 509                 dprintk(1, "qbuf: buffer is already queued or active.\n");
 510                 goto done;
 511         }
 512
 513         if (b->flags & V4L2_BUF_FLAG_INPUT) {
 514                 if (b->input >= q->inputs) {
 515                         dprintk(1, "qbuf: wrong input.\n");
 516                         goto done;
 517                 }
 518                 buf->input = b->input;
 519         } else {
 520                 buf->input = UNSET;
 521         }
 522
 523         switch (b->memory) {
 524         case V4L2_MEMORY_MMAP:
 525                 if (0 == buf->baddr) {
 526                         dprintk(1, "qbuf: mmap requested "
 527                                    "but buffer addr is zero!\n");
 528                         goto done;
 529                 }
 530                 break;
 531         case V4L2_MEMORY_USERPTR:
 532                 if (b->length < buf->bsize) {
 533                         dprintk(1, "qbuf: buffer length is not enough\n");
 534                         goto done;
 535                 }
 536                 if (VIDEOBUF_NEEDS_INIT != buf->state &&
 537                     buf->baddr != b->m.userptr)
 538                         q->ops->buf_release(q, buf);
 539                 buf->baddr = b->m.userptr;
 540                 break;
 541         case V4L2_MEMORY_OVERLAY:
 542                 buf->boff = b->m.offset;
 543                 break;
 544         default:
 545                 dprintk(1, "qbuf: wrong memory type\n");
 546                 goto done;
 547         }
 548
 549         dprintk(1, "qbuf: requesting next field\n");
 550         field = videobuf_next_field(q);
 551         retval = q->ops->buf_prepare(q, buf, field);
 552         if (0 != retval) {
 553                 dprintk(1, "qbuf: buffer_prepare returned %d\n", retval);
 554                 goto done;
 555         }
 556
 557         list_add_tail(&buf->stream, &q->stream);
 558         if (q->streaming) {
 559                 spin_lock_irqsave(q->irqlock, flags);
 560                 q->ops->buf_queue(q, buf);
 561                 spin_unlock_irqrestore(q->irqlock, flags);
 562         }
 563         dprintk(1, "qbuf: succeded\n");
 564         retval = 0;
 565         wake_up_interruptible_sync(&q->wait);
 566
 567  done:
 568         mutex_unlock(&q->vb_lock);
 569
 570         if (b->memory == V4L2_MEMORY_MMAP)
 571                 up_read(&current->mm->mmap_sem);
 572
 573         return retval;
 574 }
 575
 576
 577 /* Locking: Caller holds q->vb_lock */
 578 static int stream_next_buffer_check_queue(struct videobuf_queue *q, int noblock)
 579 {
 580         int retval;
 581
 582 checks:
 583         if (!q->streaming) {
 584                 dprintk(1, "next_buffer: Not streaming\n");
 585                 retval = -EINVAL;
 586                 goto done;
 587         }
 588
 589         if (list_empty(&q->stream)) {
 590                 if (noblock) {
 591                         retval = -EAGAIN;
 592                         dprintk(2, "next_buffer: no buffers to dequeue\n");
 593                         goto done;
 594                 } else {
 595                         dprintk(2, "next_buffer: waiting on buffer\n");
 596
 597                         /* Drop lock to avoid deadlock with qbuf */
 598                         mutex_unlock(&q->vb_lock);
 599
 600                         /* Checking list_empty and streaming is safe without
 601                          * locks because we goto checks to validate while
 602                          * holding locks before proceeding */
 603                         retval = wait_event_interruptible(q->wait,
 604                                 !list_empty(&q->stream) || !q->streaming);
 605                         mutex_lock(&q->vb_lock);
 606
 607                         if (retval)
 608                                 goto done;
 609
 610                         goto checks;
 611                 }
 612         }
 613
 614         retval = 0;
 615
 616 done:
 617         return retval;
 618 }
 619
 620
 621 /* Locking: Caller holds q->vb_lock */
 622 static int stream_next_buffer(struct videobuf_queue *q,
 623                         struct videobuf_buffer **vb, int nonblocking)
 624 {
 625         int retval;
 626         struct videobuf_buffer *buf = NULL;
 627
 628         retval = stream_next_buffer_check_queue(q, nonblocking);
 629         if (retval)
 630                 goto done;
 631
 632         buf = list_entry(q->stream.next, struct videobuf_buffer, stream);
 633         retval = videobuf_waiton(buf, nonblocking, 1);
 634         if (retval < 0)
 635                 goto done;
 636
 637         *vb = buf;
 638 done:
 639         return retval;
 640 }
 641
 642 int videobuf_dqbuf(struct videobuf_queue *q,
 643                struct v4l2_buffer *b, int nonblocking)
 644 {
 645         struct videobuf_buffer *buf = NULL;
 646         int retval;
 647
 648         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 649
 650         mutex_lock(&q->vb_lock);
 651
 652         retval = stream_next_buffer(q, &buf, nonblocking);
 653         if (retval < 0) {
 654                 dprintk(1, "dqbuf: next_buffer error: %i\n", retval);
 655                 goto done;
 656         }
 657
 658         switch (buf->state) {
 659         case VIDEOBUF_ERROR:
 660                 dprintk(1, "dqbuf: state is error\n");
 661                 retval = -EIO;
 662                 CALL(q, sync, q, buf);
 663                 buf->state = VIDEOBUF_IDLE;
 664                 break;
 665         case VIDEOBUF_DONE:
 666                 dprintk(1, "dqbuf: state is done\n");
 667                 CALL(q, sync, q, buf);
 668                 buf->state = VIDEOBUF_IDLE;
 669                 break;
 670         default:
 671                 dprintk(1, "dqbuf: state invalid\n");
 672                 retval = -EINVAL;
 673                 goto done;
 674         }
 675         list_del(&buf->stream);
 676         memset(b, 0, sizeof(*b));
 677         videobuf_status(q, b, buf, q->type);
 678
 679  done:
 680         mutex_unlock(&q->vb_lock);
 681         return retval;
 682 }
 683
 684 int videobuf_streamon(struct videobuf_queue *q)
 685 {
 686         struct videobuf_buffer *buf;
 687         unsigned long flags = 0;
 688         int retval;
 689
 690         mutex_lock(&q->vb_lock);
 691         retval = -EBUSY;
 692         if (q->reading)
 693                 goto done;
 694         retval = 0;
 695         if (q->streaming)
 696                 goto done;
 697         q->streaming = 1;
 698         spin_lock_irqsave(q->irqlock, flags);
 699         list_for_each_entry(buf, &q->stream, stream)
 700                 if (buf->state == VIDEOBUF_PREPARED)
 701                         q->ops->buf_queue(q, buf);
 702         spin_unlock_irqrestore(q->irqlock, flags);
 703
 704         wake_up_interruptible_sync(&q->wait);
 705  done:
 706         mutex_unlock(&q->vb_lock);
 707         return retval;
 708 }
 709
 710 /* Locking: Caller holds q->vb_lock */
 711 static int __videobuf_streamoff(struct videobuf_queue *q)
 712 {
 713         if (!q->streaming)
 714                 return -EINVAL;
 715
 716         videobuf_queue_cancel(q);
 717
 718         return 0;
 719 }
 720
 721 int videobuf_streamoff(struct videobuf_queue *q)
 722 {
 723         int retval;
 724
 725         mutex_lock(&q->vb_lock);
 726         retval = __videobuf_streamoff(q);
 727         mutex_unlock(&q->vb_lock);
 728
 729         return retval;
 730 }
 731
 732 /* Locking: Caller holds q->vb_lock */
 733 static ssize_t videobuf_read_zerocopy(struct videobuf_queue *q,
 734                                       char __user *data,
 735                                       size_t count, loff_t *ppos)
 736 {
 737         enum v4l2_field field;
 738         unsigned long flags = 0;
 739         int retval;
 740
 741         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 742
 743         /* setup stuff */
 744         q->read_buf = videobuf_alloc(q);
 745         if (NULL == q->read_buf)
 746                 return -ENOMEM;
 747
 748         q->read_buf->memory = V4L2_MEMORY_USERPTR;
 749         q->read_buf->baddr  = (unsigned long)data;
 750         q->read_buf->bsize  = count;
 751
 752         field = videobuf_next_field(q);
 753         retval = q->ops->buf_prepare(q, q->read_buf, field);
 754         if (0 != retval)
 755                 goto done;
 756
 757         /* start capture & wait */
 758         spin_lock_irqsave(q->irqlock, flags);
 759         q->ops->buf_queue(q, q->read_buf);
 760         spin_unlock_irqrestore(q->irqlock, flags);
 761         retval = videobuf_waiton(q->read_buf, 0, 0);
 762         if (0 == retval) {
 763                 CALL(q, sync, q, q->read_buf);
 764                 if (VIDEOBUF_ERROR == q->read_buf->state)
 765                         retval = -EIO;
 766                 else
 767                         retval = q->read_buf->size;
 768         }
 769
 770  done:
 771         /* cleanup */
 772         q->ops->buf_release(q, q->read_buf);
 773         kfree(q->read_buf);
 774         q->read_buf = NULL;
 775         return retval;
 776 }
 777
 778 ssize_t videobuf_read_one(struct videobuf_queue *q,
 779                           char __user *data, size_t count, loff_t *ppos,
 780                           int nonblocking)
 781 {
 782         enum v4l2_field field;
 783         unsigned long flags = 0;
 784         unsigned size = 0, nbufs = 1;
 785         int retval;
 786
 787         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 788
 789         mutex_lock(&q->vb_lock);
 790
 791         q->ops->buf_setup(q, &nbufs, &size);
 792
 793         if (NULL == q->read_buf  &&
 794             count >= size        &&
 795             !nonblocking) {
 796                 retval = videobuf_read_zerocopy(q, data, count, ppos);
 797                 if (retval >= 0  ||  retval == -EIO)
 798                         /* ok, all done */
 799                         goto done;
 800                 /* fallback to kernel bounce buffer on failures */
 801         }
 802
 803         if (NULL == q->read_buf) {
 804                 /* need to capture a new frame */
 805                 retval = -ENOMEM;
 806                 q->read_buf = videobuf_alloc(q);
 807
 808                 dprintk(1, "video alloc=0x%p\n", q->read_buf);
 809                 if (NULL == q->read_buf)
 810                         goto done;
 811                 q->read_buf->memory = V4L2_MEMORY_USERPTR;
 812                 q->read_buf->bsize = count; /* preferred size */
 813                 field = videobuf_next_field(q);
 814                 retval = q->ops->buf_prepare(q, q->read_buf, field);
 815
 816                 if (0 != retval) {
 817                         kfree(q->read_buf);
 818                         q->read_buf = NULL;
 819                         goto done;
 820                 }
 821
 822                 spin_lock_irqsave(q->irqlock, flags);
 823                 q->ops->buf_queue(q, q->read_buf);
 824                 spin_unlock_irqrestore(q->irqlock, flags);
 825
 826                 q->read_off = 0;
 827         }
 828
 829         /* wait until capture is done */
 830         retval = videobuf_waiton(q->read_buf, nonblocking, 1);
 831         if (0 != retval)
 832                 goto done;
 833
 834         CALL(q, sync, q, q->read_buf);
 835
 836         if (VIDEOBUF_ERROR == q->read_buf->state) {
 837                 /* catch I/O errors */
 838                 q->ops->buf_release(q, q->read_buf);
 839                 kfree(q->read_buf);
 840                 q->read_buf = NULL;
 841                 retval = -EIO;
 842                 goto done;
 843         }
 844
 845         /* Copy to userspace */
 846         retval = CALL(q, video_copy_to_user, q, data, count, nonblocking);
 847         if (retval < 0)
 848                 goto done;
 849
 850         q->read_off += retval;
 851         if (q->read_off == q->read_buf->size) {
 852                 /* all data copied, cleanup */
 853                 q->ops->buf_release(q, q->read_buf);
 854                 kfree(q->read_buf);
 855                 q->read_buf = NULL;
 856         }
 857
 858  done:
 859         mutex_unlock(&q->vb_lock);
 860         return retval;
 861 }
 862
 863 /* Locking: Caller holds q->vb_lock */
 864 static int __videobuf_read_start(struct videobuf_queue *q)
 865 {
 866         enum v4l2_field field;
 867         unsigned long flags = 0;
 868         unsigned int count = 0, size = 0;
 869         int err, i;
 870
 871         q->ops->buf_setup(q, &count, &size);
 872         if (count < 2)
 873                 count = 2;
 874         if (count > VIDEO_MAX_FRAME)
 875                 count = VIDEO_MAX_FRAME;
 876         size = PAGE_ALIGN(size);
 877
 878         err = __videobuf_mmap_setup(q, count, size, V4L2_MEMORY_USERPTR);
 879         if (err < 0)
 880                 return err;
 881
 882         count = err;
 883
 884         for (i = 0; i < count; i++) {
 885                 field = videobuf_next_field(q);
 886                 err = q->ops->buf_prepare(q, q->bufs[i], field);
 887                 if (err)
 888                         return err;
 889                 list_add_tail(&q->bufs[i]->stream, &q->stream);
 890         }
 891         spin_lock_irqsave(q->irqlock, flags);
 892         for (i = 0; i < count; i++)
 893                 q->ops->buf_queue(q, q->bufs[i]);
 894         spin_unlock_irqrestore(q->irqlock, flags);
 895         q->reading = 1;
 896         return 0;
 897 }
 898
 899 static void __videobuf_read_stop(struct videobuf_queue *q)
 900 {
 901         int i;
 902
 903         videobuf_queue_cancel(q);
 904         __videobuf_mmap_free(q);
 905         INIT_LIST_HEAD(&q->stream);
 906         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 907                 if (NULL == q->bufs[i])
 908                         continue;
 909                 kfree(q->bufs[i]);
 910                 q->bufs[i] = NULL;
 911         }
 912         q->read_buf = NULL;
 913
 914 }
 915
 916 int videobuf_read_start(struct videobuf_queue *q)
 917 {
 918         int rc;
 919
 920         mutex_lock(&q->vb_lock);
 921         rc = __videobuf_read_start(q);
 922         mutex_unlock(&q->vb_lock);
 923
 924         return rc;
 925 }
 926
 927 void videobuf_read_stop(struct videobuf_queue *q)
 928 {
 929         mutex_lock(&q->vb_lock);
 930         __videobuf_read_stop(q);
 931         mutex_unlock(&q->vb_lock);
 932 }
 933
 934 void videobuf_stop(struct videobuf_queue *q)
 935 {
 936         mutex_lock(&q->vb_lock);
 937
 938         if (q->streaming)
 939                 __videobuf_streamoff(q);
 940
 941         if (q->reading)
 942                 __videobuf_read_stop(q);
 943
 944         mutex_unlock(&q->vb_lock);
 945 }
 946
 947
 948 ssize_t videobuf_read_stream(struct videobuf_queue *q,
 949                              char __user *data, size_t count, loff_t *ppos,
 950                              int vbihack, int nonblocking)
 951 {
 952         int rc, retval;
 953         unsigned long flags = 0;
 954
 955         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 956
 957         dprintk(2, "%s\n", __func__);
 958         mutex_lock(&q->vb_lock);
 959         retval = -EBUSY;
 960         if (q->streaming)
 961                 goto done;
 962         if (!q->reading) {
 963                 retval = __videobuf_read_start(q);
 964                 if (retval < 0)
 965                         goto done;
 966         }
 967
 968         retval = 0;
 969         while (count > 0) {
 970                 /* get / wait for data */
 971                 if (NULL == q->read_buf) {
 972                         q->read_buf = list_entry(q->stream.next,
 973                                                  struct videobuf_buffer,
 974                                                  stream);
 975                         list_del(&q->read_buf->stream);
 976                         q->read_off = 0;
 977                 }
 978                 rc = videobuf_waiton(q->read_buf, nonblocking, 1);
 979                 if (rc < 0) {
 980                         if (0 == retval)
 981                                 retval = rc;
 982                         break;
 983                 }
 984
 985                 if (q->read_buf->state == VIDEOBUF_DONE) {
 986                         rc = CALL(q, copy_stream, q, data + retval, count,
 987                                         retval, vbihack, nonblocking);
 988                         if (rc < 0) {
 989                                 retval = rc;
 990                                 break;
 991                         }
 992                         retval      += rc;
 993                         count       -= rc;
 994                         q->read_off += rc;
 995                 } else {
 996                         /* some error */
 997                         q->read_off = q->read_buf->size;
 998                         if (0 == retval)
 999                                 retval = -EIO;
1000                 }
1001
1002                 /* requeue buffer when done with copying */
1003                 if (q->read_off == q->read_buf->size) {
1004                         list_add_tail(&q->read_buf->stream,
1005                                       &q->stream);
1006                         spin_lock_irqsave(q->irqlock, flags);
1007                         q->ops->buf_queue(q, q->read_buf);
1008                         spin_unlock_irqrestore(q->irqlock, flags);
1009                         q->read_buf = NULL;
1010                 }
1011                 if (retval < 0)
1012                         break;
1013         }
1014
1015  done:
1016         mutex_unlock(&q->vb_lock);
1017         return retval;
1018 }
1019
1020 unsigned int videobuf_poll_stream(struct file *file,
1021                                   struct videobuf_queue *q,
1022                                   poll_table *wait)
1023 {
1024         struct videobuf_buffer *buf = NULL;
1025         unsigned int rc = 0;
1026
1027         mutex_lock(&q->vb_lock);
1028         if (q->streaming) {
1029                 if (!list_empty(&q->stream))
1030                         buf = list_entry(q->stream.next,
1031                                          struct videobuf_buffer, stream);
1032         } else {
1033                 if (!q->reading)
1034                         __videobuf_read_start(q);
1035                 if (!q->reading) {
1036                         rc = POLLERR;
1037                 } else if (NULL == q->read_buf) {
1038                         q->read_buf = list_entry(q->stream.next,
1039                                                  struct videobuf_buffer,
1040                                                  stream);
1041                         list_del(&q->read_buf->stream);
1042                         q->read_off = 0;
1043                 }
1044                 buf = q->read_buf;
1045         }
1046         if (!buf)
1047                 rc = POLLERR;
1048
1049         if (0 == rc) {
1050                 poll_wait(file, &buf->done, wait);
1051                 if (buf->state == VIDEOBUF_DONE ||
1052                     buf->state == VIDEOBUF_ERROR)
1053                         rc = POLLIN|POLLRDNORM;
1054         }
1055         mutex_unlock(&q->vb_lock);
1056         return rc;
1057 }
1058
1059 int videobuf_mmap_mapper(struct videobuf_queue *q,
1060                          struct vm_area_struct *vma)
1061 {
1062         int retval;
1063
1064         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
1065
1066         mutex_lock(&q->vb_lock);
1067         retval = CALL(q, mmap_mapper, q, vma);
1068         q->is_mmapped = 1;
1069         mutex_unlock(&q->vb_lock);
1070
1071         return retval;
1072 }
1073
1074 #ifdef CONFIG_VIDEO_V4L1_COMPAT
1075 int videobuf_cgmbuf(struct videobuf_queue *q,
1076                     struct video_mbuf *mbuf, int count)
1077 {
1078         struct v4l2_requestbuffers req;
1079         int rc, i;
1080
1081         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
1082
1083         memset(&req, 0, sizeof(req));
1084         req.type   = q->type;
1085         req.count  = count;
1086         req.memory = V4L2_MEMORY_MMAP;
1087         rc = videobuf_reqbufs(q, &req);
1088         if (rc < 0)
1089                 return rc;
1090
1091         mbuf->frames = req.count;
1092         mbuf->size   = 0;
1093         for (i = 0; i < mbuf->frames; i++) {
1094                 mbuf->offsets[i]  = q->bufs[i]->boff;
1095                 mbuf->size       += q->bufs[i]->bsize;
1096         }
1097
1098         return 0;
1099 }
1100 EXPORT_SYMBOL_GPL(videobuf_cgmbuf);
1101 #endif
1102
1103 /* --------------------------------------------------------------------- */
1104
1105 EXPORT_SYMBOL_GPL(videobuf_waiton);
1106 EXPORT_SYMBOL_GPL(videobuf_iolock);
1107
1108 EXPORT_SYMBOL_GPL(videobuf_alloc);
1109
1110 EXPORT_SYMBOL_GPL(videobuf_queue_core_init);
1111 EXPORT_SYMBOL_GPL(videobuf_queue_cancel);
1112 EXPORT_SYMBOL_GPL(videobuf_queue_is_busy);
1113
1114 EXPORT_SYMBOL_GPL(videobuf_next_field);
1115 EXPORT_SYMBOL_GPL(videobuf_reqbufs);
1116 EXPORT_SYMBOL_GPL(videobuf_querybuf);
1117 EXPORT_SYMBOL_GPL(videobuf_qbuf);
1118 EXPORT_SYMBOL_GPL(videobuf_dqbuf);
1119 EXPORT_SYMBOL_GPL(videobuf_streamon);
1120 EXPORT_SYMBOL_GPL(videobuf_streamoff);
1121
1122 EXPORT_SYMBOL_GPL(videobuf_read_start);
1123 EXPORT_SYMBOL_GPL(videobuf_read_stop);
1124 EXPORT_SYMBOL_GPL(videobuf_stop);
1125 EXPORT_SYMBOL_GPL(videobuf_read_stream);
1126 EXPORT_SYMBOL_GPL(videobuf_read_one);
1127 EXPORT_SYMBOL_GPL(videobuf_poll_stream);
1128
1129 EXPORT_SYMBOL_GPL(videobuf_mmap_setup);
1130 EXPORT_SYMBOL_GPL(videobuf_mmap_free);
1131 EXPORT_SYMBOL_GPL(videobuf_mmap_mapper);