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/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
  55 struct videobuf_buffer *videobuf_alloc_vb(struct videobuf_queue *q)
  56 {
  57         struct videobuf_buffer *vb;
  58
  59         BUG_ON(q->msize < sizeof(*vb));
  60
  61         if (!q->int_ops || !q->int_ops->alloc_vb) {
  62                 printk(KERN_ERR "No specific ops defined!\n");
  63                 BUG();
  64         }
  65
  66         vb = q->int_ops->alloc_vb(q->msize);
  67         if (NULL != vb) {
  68                 init_waitqueue_head(&vb->done);
  69                 vb->magic = MAGIC_BUFFER;
  70         }
  71
  72         return vb;
  73 }
  74 EXPORT_SYMBOL_GPL(videobuf_alloc_vb);
  75
  76 static int is_state_active_or_queued(struct videobuf_queue *q, struct videobuf_buffer *vb)
  77 {
  78         unsigned long flags;
  79         bool rc;
  80
  81         spin_lock_irqsave(q->irqlock, flags);
  82         rc = vb->state != VIDEOBUF_ACTIVE && vb->state != VIDEOBUF_QUEUED;
  83         spin_unlock_irqrestore(q->irqlock, flags);
  84         return rc;
  85 };
  86
  87 int videobuf_waiton(struct videobuf_queue *q, struct videobuf_buffer *vb,
  88                 int non_blocking, int intr)
  89 {
  90         bool is_ext_locked;
  91         int ret = 0;
  92
  93         MAGIC_CHECK(vb->magic, MAGIC_BUFFER);
  94
  95         if (non_blocking) {
  96                 if (is_state_active_or_queued(q, vb))
  97                         return 0;
  98                 return -EAGAIN;
  99         }
 100
 101         is_ext_locked = q->ext_lock && mutex_is_locked(q->ext_lock);
 102
 103         /* Release vdev lock to prevent this wait from blocking outside access to
 104            the device. */
 105         if (is_ext_locked)
 106                 mutex_unlock(q->ext_lock);
 107         if (intr)
 108                 ret = wait_event_interruptible(vb->done, is_state_active_or_queued(q, vb));
 109         else
 110                 wait_event(vb->done, is_state_active_or_queued(q, vb));
 111         /* Relock */
 112         if (is_ext_locked)
 113                 mutex_lock(q->ext_lock);
 114
 115         return ret;
 116 }
 117 EXPORT_SYMBOL_GPL(videobuf_waiton);
 118
 119 int videobuf_iolock(struct videobuf_queue *q, struct videobuf_buffer *vb,
 120                     struct v4l2_framebuffer *fbuf)
 121 {
 122         MAGIC_CHECK(vb->magic, MAGIC_BUFFER);
 123         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 124
 125         return CALL(q, iolock, q, vb, fbuf);
 126 }
 127 EXPORT_SYMBOL_GPL(videobuf_iolock);
 128
 129 void *videobuf_queue_to_vaddr(struct videobuf_queue *q,
 130                               struct videobuf_buffer *buf)
 131 {
 132         if (q->int_ops->vaddr)
 133                 return q->int_ops->vaddr(buf);
 134         return NULL;
 135 }
 136 EXPORT_SYMBOL_GPL(videobuf_queue_to_vaddr);
 137
 138 /* --------------------------------------------------------------------- */
 139
 140
 141 void videobuf_queue_core_init(struct videobuf_queue *q,
 142                          const struct videobuf_queue_ops *ops,
 143                          struct device *dev,
 144                          spinlock_t *irqlock,
 145                          enum v4l2_buf_type type,
 146                          enum v4l2_field field,
 147                          unsigned int msize,
 148                          void *priv,
 149                          struct videobuf_qtype_ops *int_ops,
 150                          struct mutex *ext_lock)
 151 {
 152         BUG_ON(!q);
 153         memset(q, 0, sizeof(*q));
 154         q->irqlock   = irqlock;
 155         q->ext_lock  = ext_lock;
 156         q->dev       = dev;
 157         q->type      = type;
 158         q->field     = field;
 159         q->msize     = msize;
 160         q->ops       = ops;
 161         q->priv_data = priv;
 162         q->int_ops   = int_ops;
 163
 164         /* All buffer operations are mandatory */
 165         BUG_ON(!q->ops->buf_setup);
 166         BUG_ON(!q->ops->buf_prepare);
 167         BUG_ON(!q->ops->buf_queue);
 168         BUG_ON(!q->ops->buf_release);
 169
 170         /* Lock is mandatory for queue_cancel to work */
 171         BUG_ON(!irqlock);
 172
 173         /* Having implementations for abstract methods are mandatory */
 174         BUG_ON(!q->int_ops);
 175
 176         mutex_init(&q->vb_lock);
 177         init_waitqueue_head(&q->wait);
 178         INIT_LIST_HEAD(&q->stream);
 179 }
 180 EXPORT_SYMBOL_GPL(videobuf_queue_core_init);
 181
 182 /* Locking: Only usage in bttv unsafe find way to remove */
 183 int videobuf_queue_is_busy(struct videobuf_queue *q)
 184 {
 185         int i;
 186
 187         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 188
 189         if (q->streaming) {
 190                 dprintk(1, "busy: streaming active\n");
 191                 return 1;
 192         }
 193         if (q->reading) {
 194                 dprintk(1, "busy: pending read #1\n");
 195                 return 1;
 196         }
 197         if (q->read_buf) {
 198                 dprintk(1, "busy: pending read #2\n");
 199                 return 1;
 200         }
 201         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 202                 if (NULL == q->bufs[i])
 203                         continue;
 204                 if (q->bufs[i]->map) {
 205                         dprintk(1, "busy: buffer #%d mapped\n", i);
 206                         return 1;
 207                 }
 208                 if (q->bufs[i]->state == VIDEOBUF_QUEUED) {
 209                         dprintk(1, "busy: buffer #%d queued\n", i);
 210                         return 1;
 211                 }
 212                 if (q->bufs[i]->state == VIDEOBUF_ACTIVE) {
 213                         dprintk(1, "busy: buffer #%d avtive\n", i);
 214                         return 1;
 215                 }
 216         }
 217         return 0;
 218 }
 219 EXPORT_SYMBOL_GPL(videobuf_queue_is_busy);
 220
 221 /**
 222  * __videobuf_free() - free all the buffers and their control structures
 223  *
 224  * This function can only be called if streaming/reading is off, i.e. no buffers
 225  * are under control of the driver.
 226  */
 227 /* Locking: Caller holds q->vb_lock */
 228 static int __videobuf_free(struct videobuf_queue *q)
 229 {
 230         int i;
 231
 232         dprintk(1, "%s\n", __func__);
 233         if (!q)
 234                 return 0;
 235
 236         if (q->streaming || q->reading) {
 237                 dprintk(1, "Cannot free buffers when streaming or reading\n");
 238                 return -EBUSY;
 239         }
 240
 241         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 242
 243         for (i = 0; i < VIDEO_MAX_FRAME; i++)
 244                 if (q->bufs[i] && q->bufs[i]->map) {
 245                         dprintk(1, "Cannot free mmapped buffers\n");
 246                         return -EBUSY;
 247                 }
 248
 249         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 250                 if (NULL == q->bufs[i])
 251                         continue;
 252                 q->ops->buf_release(q, q->bufs[i]);
 253                 kfree(q->bufs[i]);
 254                 q->bufs[i] = NULL;
 255         }
 256
 257         return 0;
 258 }
 259
 260 /* Locking: Caller holds q->vb_lock */
 261 void videobuf_queue_cancel(struct videobuf_queue *q)
 262 {
 263         unsigned long flags = 0;
 264         int i;
 265
 266         q->streaming = 0;
 267         q->reading  = 0;
 268         wake_up_interruptible_sync(&q->wait);
 269
 270         /* remove queued buffers from list */
 271         spin_lock_irqsave(q->irqlock, flags);
 272         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 273                 if (NULL == q->bufs[i])
 274                         continue;
 275                 if (q->bufs[i]->state == VIDEOBUF_QUEUED) {
 276                         list_del(&q->bufs[i]->queue);
 277                         q->bufs[i]->state = VIDEOBUF_ERROR;
 278                         wake_up_all(&q->bufs[i]->done);
 279                 }
 280         }
 281         spin_unlock_irqrestore(q->irqlock, flags);
 282
 283         /* free all buffers + clear queue */
 284         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 285                 if (NULL == q->bufs[i])
 286                         continue;
 287                 q->ops->buf_release(q, q->bufs[i]);
 288         }
 289         INIT_LIST_HEAD(&q->stream);
 290 }
 291 EXPORT_SYMBOL_GPL(videobuf_queue_cancel);
 292
 293 /* --------------------------------------------------------------------- */
 294
 295 /* Locking: Caller holds q->vb_lock */
 296 enum v4l2_field videobuf_next_field(struct videobuf_queue *q)
 297 {
 298         enum v4l2_field field = q->field;
 299
 300         BUG_ON(V4L2_FIELD_ANY == field);
 301
 302         if (V4L2_FIELD_ALTERNATE == field) {
 303                 if (V4L2_FIELD_TOP == q->last) {
 304                         field   = V4L2_FIELD_BOTTOM;
 305                         q->last = V4L2_FIELD_BOTTOM;
 306                 } else {
 307                         field   = V4L2_FIELD_TOP;
 308                         q->last = V4L2_FIELD_TOP;
 309                 }
 310         }
 311         return field;
 312 }
 313 EXPORT_SYMBOL_GPL(videobuf_next_field);
 314
 315 /* Locking: Caller holds q->vb_lock */
 316 static void videobuf_status(struct videobuf_queue *q, struct v4l2_buffer *b,
 317                             struct videobuf_buffer *vb, enum v4l2_buf_type type)
 318 {
 319         MAGIC_CHECK(vb->magic, MAGIC_BUFFER);
 320         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 321
 322         b->index    = vb->i;
 323         b->type     = type;
 324
 325         b->memory   = vb->memory;
 326         switch (b->memory) {
 327         case V4L2_MEMORY_MMAP:
 328                 b->m.offset  = vb->boff;
 329                 b->length    = vb->bsize;
 330                 break;
 331         case V4L2_MEMORY_USERPTR:
 332                 b->m.userptr = vb->baddr;
 333                 b->length    = vb->bsize;
 334                 break;
 335         case V4L2_MEMORY_OVERLAY:
 336                 b->m.offset  = vb->boff;
 337                 break;
 338         }
 339
 340         b->flags    = 0;
 341         if (vb->map)
 342                 b->flags |= V4L2_BUF_FLAG_MAPPED;
 343
 344         switch (vb->state) {
 345         case VIDEOBUF_PREPARED:
 346         case VIDEOBUF_QUEUED:
 347         case VIDEOBUF_ACTIVE:
 348                 b->flags |= V4L2_BUF_FLAG_QUEUED;
 349                 break;
 350         case VIDEOBUF_ERROR:
 351                 b->flags |= V4L2_BUF_FLAG_ERROR;
 352                 /* fall through */
 353         case VIDEOBUF_DONE:
 354                 b->flags |= V4L2_BUF_FLAG_DONE;
 355                 break;
 356         case VIDEOBUF_NEEDS_INIT:
 357         case VIDEOBUF_IDLE:
 358                 /* nothing */
 359                 break;
 360         }
 361
 362         if (vb->input != UNSET) {
 363                 b->flags |= V4L2_BUF_FLAG_INPUT;
 364                 b->input  = vb->input;
 365         }
 366
 367         b->field     = vb->field;
 368         b->timestamp = vb->ts;
 369         b->bytesused = vb->size;
 370         b->sequence  = vb->field_count >> 1;
 371 }
 372
 373 int videobuf_mmap_free(struct videobuf_queue *q)
 374 {
 375         int ret;
 376         videobuf_queue_lock(q);
 377         ret = __videobuf_free(q);
 378         videobuf_queue_unlock(q);
 379         return ret;
 380 }
 381 EXPORT_SYMBOL_GPL(videobuf_mmap_free);
 382
 383 /* Locking: Caller holds q->vb_lock */
 384 int __videobuf_mmap_setup(struct videobuf_queue *q,
 385                         unsigned int bcount, unsigned int bsize,
 386                         enum v4l2_memory memory)
 387 {
 388         unsigned int i;
 389         int err;
 390
 391         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 392
 393         err = __videobuf_free(q);
 394         if (0 != err)
 395                 return err;
 396
 397         /* Allocate and initialize buffers */
 398         for (i = 0; i < bcount; i++) {
 399                 q->bufs[i] = videobuf_alloc_vb(q);
 400
 401                 if (NULL == q->bufs[i])
 402                         break;
 403
 404                 q->bufs[i]->i      = i;
 405                 q->bufs[i]->input  = UNSET;
 406                 q->bufs[i]->memory = memory;
 407                 q->bufs[i]->bsize  = bsize;
 408                 switch (memory) {
 409                 case V4L2_MEMORY_MMAP:
 410                         q->bufs[i]->boff = PAGE_ALIGN(bsize) * i;
 411                         break;
 412                 case V4L2_MEMORY_USERPTR:
 413                 case V4L2_MEMORY_OVERLAY:
 414                         /* nothing */
 415                         break;
 416                 }
 417         }
 418
 419         if (!i)
 420                 return -ENOMEM;
 421
 422         dprintk(1, "mmap setup: %d buffers, %d bytes each\n", i, bsize);
 423
 424         return i;
 425 }
 426 EXPORT_SYMBOL_GPL(__videobuf_mmap_setup);
 427
 428 int videobuf_mmap_setup(struct videobuf_queue *q,
 429                         unsigned int bcount, unsigned int bsize,
 430                         enum v4l2_memory memory)
 431 {
 432         int ret;
 433         videobuf_queue_lock(q);
 434         ret = __videobuf_mmap_setup(q, bcount, bsize, memory);
 435         videobuf_queue_unlock(q);
 436         return ret;
 437 }
 438 EXPORT_SYMBOL_GPL(videobuf_mmap_setup);
 439
 440 int videobuf_reqbufs(struct videobuf_queue *q,
 441                  struct v4l2_requestbuffers *req)
 442 {
 443         unsigned int size, count;
 444         int retval;
 445
 446         if (req->count < 1) {
 447                 dprintk(1, "reqbufs: count invalid (%d)\n", req->count);
 448                 return -EINVAL;
 449         }
 450
 451         if (req->memory != V4L2_MEMORY_MMAP     &&
 452             req->memory != V4L2_MEMORY_USERPTR  &&
 453             req->memory != V4L2_MEMORY_OVERLAY) {
 454                 dprintk(1, "reqbufs: memory type invalid\n");
 455                 return -EINVAL;
 456         }
 457
 458         videobuf_queue_lock(q);
 459         if (req->type != q->type) {
 460                 dprintk(1, "reqbufs: queue type invalid\n");
 461                 retval = -EINVAL;
 462                 goto done;
 463         }
 464
 465         if (q->streaming) {
 466                 dprintk(1, "reqbufs: streaming already exists\n");
 467                 retval = -EBUSY;
 468                 goto done;
 469         }
 470         if (!list_empty(&q->stream)) {
 471                 dprintk(1, "reqbufs: stream running\n");
 472                 retval = -EBUSY;
 473                 goto done;
 474         }
 475
 476         count = req->count;
 477         if (count > VIDEO_MAX_FRAME)
 478                 count = VIDEO_MAX_FRAME;
 479         size = 0;
 480         q->ops->buf_setup(q, &count, &size);
 481         dprintk(1, "reqbufs: bufs=%d, size=0x%x [%u pages total]\n",
 482                 count, size,
 483                 (unsigned int)((count * PAGE_ALIGN(size)) >> PAGE_SHIFT));
 484
 485         retval = __videobuf_mmap_setup(q, count, size, req->memory);
 486         if (retval < 0) {
 487                 dprintk(1, "reqbufs: mmap setup returned %d\n", retval);
 488                 goto done;
 489         }
 490
 491         req->count = retval;
 492         retval = 0;
 493
 494  done:
 495         videobuf_queue_unlock(q);
 496         return retval;
 497 }
 498 EXPORT_SYMBOL_GPL(videobuf_reqbufs);
 499
 500 int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b)
 501 {
 502         int ret = -EINVAL;
 503
 504         videobuf_queue_lock(q);
 505         if (unlikely(b->type != q->type)) {
 506                 dprintk(1, "querybuf: Wrong type.\n");
 507                 goto done;
 508         }
 509         if (unlikely(b->index >= VIDEO_MAX_FRAME)) {
 510                 dprintk(1, "querybuf: index out of range.\n");
 511                 goto done;
 512         }
 513         if (unlikely(NULL == q->bufs[b->index])) {
 514                 dprintk(1, "querybuf: buffer is null.\n");
 515                 goto done;
 516         }
 517
 518         videobuf_status(q, b, q->bufs[b->index], q->type);
 519
 520         ret = 0;
 521 done:
 522         videobuf_queue_unlock(q);
 523         return ret;
 524 }
 525 EXPORT_SYMBOL_GPL(videobuf_querybuf);
 526
 527 int videobuf_qbuf(struct videobuf_queue *q, struct v4l2_buffer *b)
 528 {
 529         struct videobuf_buffer *buf;
 530         enum v4l2_field field;
 531         unsigned long flags = 0;
 532         int retval;
 533
 534         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 535
 536         if (b->memory == V4L2_MEMORY_MMAP)
 537                 down_read(&current->mm->mmap_sem);
 538
 539         videobuf_queue_lock(q);
 540         retval = -EBUSY;
 541         if (q->reading) {
 542                 dprintk(1, "qbuf: Reading running...\n");
 543                 goto done;
 544         }
 545         retval = -EINVAL;
 546         if (b->type != q->type) {
 547                 dprintk(1, "qbuf: Wrong type.\n");
 548                 goto done;
 549         }
 550         if (b->index >= VIDEO_MAX_FRAME) {
 551                 dprintk(1, "qbuf: index out of range.\n");
 552                 goto done;
 553         }
 554         buf = q->bufs[b->index];
 555         if (NULL == buf) {
 556                 dprintk(1, "qbuf: buffer is null.\n");
 557                 goto done;
 558         }
 559         MAGIC_CHECK(buf->magic, MAGIC_BUFFER);
 560         if (buf->memory != b->memory) {
 561                 dprintk(1, "qbuf: memory type is wrong.\n");
 562                 goto done;
 563         }
 564         if (buf->state != VIDEOBUF_NEEDS_INIT && buf->state != VIDEOBUF_IDLE) {
 565                 dprintk(1, "qbuf: buffer is already queued or active.\n");
 566                 goto done;
 567         }
 568
 569         if (b->flags & V4L2_BUF_FLAG_INPUT) {
 570                 if (b->input >= q->inputs) {
 571                         dprintk(1, "qbuf: wrong input.\n");
 572                         goto done;
 573                 }
 574                 buf->input = b->input;
 575         } else {
 576                 buf->input = UNSET;
 577         }
 578
 579         switch (b->memory) {
 580         case V4L2_MEMORY_MMAP:
 581                 if (0 == buf->baddr) {
 582                         dprintk(1, "qbuf: mmap requested "
 583                                    "but buffer addr is zero!\n");
 584                         goto done;
 585                 }
 586                 if (q->type == V4L2_BUF_TYPE_VIDEO_OUTPUT
 587                     || q->type == V4L2_BUF_TYPE_VBI_OUTPUT
 588                     || q->type == V4L2_BUF_TYPE_SLICED_VBI_OUTPUT) {
 589                         buf->size = b->bytesused;
 590                         buf->field = b->field;
 591                         buf->ts = b->timestamp;
 592                 }
 593                 break;
 594         case V4L2_MEMORY_USERPTR:
 595                 if (b->length < buf->bsize) {
 596                         dprintk(1, "qbuf: buffer length is not enough\n");
 597                         goto done;
 598                 }
 599                 if (VIDEOBUF_NEEDS_INIT != buf->state &&
 600                     buf->baddr != b->m.userptr)
 601                         q->ops->buf_release(q, buf);
 602                 buf->baddr = b->m.userptr;
 603                 break;
 604         case V4L2_MEMORY_OVERLAY:
 605                 buf->boff = b->m.offset;
 606                 break;
 607         default:
 608                 dprintk(1, "qbuf: wrong memory type\n");
 609                 goto done;
 610         }
 611
 612         dprintk(1, "qbuf: requesting next field\n");
 613         field = videobuf_next_field(q);
 614         retval = q->ops->buf_prepare(q, buf, field);
 615         if (0 != retval) {
 616                 dprintk(1, "qbuf: buffer_prepare returned %d\n", retval);
 617                 goto done;
 618         }
 619
 620         list_add_tail(&buf->stream, &q->stream);
 621         if (q->streaming) {
 622                 spin_lock_irqsave(q->irqlock, flags);
 623                 q->ops->buf_queue(q, buf);
 624                 spin_unlock_irqrestore(q->irqlock, flags);
 625         }
 626         dprintk(1, "qbuf: succeeded\n");
 627         retval = 0;
 628         wake_up_interruptible_sync(&q->wait);
 629
 630 done:
 631         videobuf_queue_unlock(q);
 632
 633         if (b->memory == V4L2_MEMORY_MMAP)
 634                 up_read(&current->mm->mmap_sem);
 635
 636         return retval;
 637 }
 638 EXPORT_SYMBOL_GPL(videobuf_qbuf);
 639
 640 /* Locking: Caller holds q->vb_lock */
 641 static int stream_next_buffer_check_queue(struct videobuf_queue *q, int noblock)
 642 {
 643         int retval;
 644
 645 checks:
 646         if (!q->streaming) {
 647                 dprintk(1, "next_buffer: Not streaming\n");
 648                 retval = -EINVAL;
 649                 goto done;
 650         }
 651
 652         if (list_empty(&q->stream)) {
 653                 if (noblock) {
 654                         retval = -EAGAIN;
 655                         dprintk(2, "next_buffer: no buffers to dequeue\n");
 656                         goto done;
 657                 } else {
 658                         dprintk(2, "next_buffer: waiting on buffer\n");
 659
 660                         /* Drop lock to avoid deadlock with qbuf */
 661                         videobuf_queue_unlock(q);
 662
 663                         /* Checking list_empty and streaming is safe without
 664                          * locks because we goto checks to validate while
 665                          * holding locks before proceeding */
 666                         retval = wait_event_interruptible(q->wait,
 667                                 !list_empty(&q->stream) || !q->streaming);
 668                         videobuf_queue_lock(q);
 669
 670                         if (retval)
 671                                 goto done;
 672
 673                         goto checks;
 674                 }
 675         }
 676
 677         retval = 0;
 678
 679 done:
 680         return retval;
 681 }
 682
 683 /* Locking: Caller holds q->vb_lock */
 684 static int stream_next_buffer(struct videobuf_queue *q,
 685                         struct videobuf_buffer **vb, int nonblocking)
 686 {
 687         int retval;
 688         struct videobuf_buffer *buf = NULL;
 689
 690         retval = stream_next_buffer_check_queue(q, nonblocking);
 691         if (retval)
 692                 goto done;
 693
 694         buf = list_entry(q->stream.next, struct videobuf_buffer, stream);
 695         retval = videobuf_waiton(q, buf, nonblocking, 1);
 696         if (retval < 0)
 697                 goto done;
 698
 699         *vb = buf;
 700 done:
 701         return retval;
 702 }
 703
 704 int videobuf_dqbuf(struct videobuf_queue *q,
 705                    struct v4l2_buffer *b, int nonblocking)
 706 {
 707         struct videobuf_buffer *buf = NULL;
 708         int retval;
 709
 710         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 711
 712         memset(b, 0, sizeof(*b));
 713         videobuf_queue_lock(q);
 714
 715         retval = stream_next_buffer(q, &buf, nonblocking);
 716         if (retval < 0) {
 717                 dprintk(1, "dqbuf: next_buffer error: %i\n", retval);
 718                 goto done;
 719         }
 720
 721         switch (buf->state) {
 722         case VIDEOBUF_ERROR:
 723                 dprintk(1, "dqbuf: state is error\n");
 724                 break;
 725         case VIDEOBUF_DONE:
 726                 dprintk(1, "dqbuf: state is done\n");
 727                 break;
 728         default:
 729                 dprintk(1, "dqbuf: state invalid\n");
 730                 retval = -EINVAL;
 731                 goto done;
 732         }
 733         CALL(q, sync, q, buf);
 734         videobuf_status(q, b, buf, q->type);
 735         list_del(&buf->stream);
 736         buf->state = VIDEOBUF_IDLE;
 737         b->flags &= ~V4L2_BUF_FLAG_DONE;
 738 done:
 739         videobuf_queue_unlock(q);
 740         return retval;
 741 }
 742 EXPORT_SYMBOL_GPL(videobuf_dqbuf);
 743
 744 int videobuf_streamon(struct videobuf_queue *q)
 745 {
 746         struct videobuf_buffer *buf;
 747         unsigned long flags = 0;
 748         int retval;
 749
 750         videobuf_queue_lock(q);
 751         retval = -EBUSY;
 752         if (q->reading)
 753                 goto done;
 754         retval = 0;
 755         if (q->streaming)
 756                 goto done;
 757         q->streaming = 1;
 758         spin_lock_irqsave(q->irqlock, flags);
 759         list_for_each_entry(buf, &q->stream, stream)
 760                 if (buf->state == VIDEOBUF_PREPARED)
 761                         q->ops->buf_queue(q, buf);
 762         spin_unlock_irqrestore(q->irqlock, flags);
 763
 764         wake_up_interruptible_sync(&q->wait);
 765 done:
 766         videobuf_queue_unlock(q);
 767         return retval;
 768 }
 769 EXPORT_SYMBOL_GPL(videobuf_streamon);
 770
 771 /* Locking: Caller holds q->vb_lock */
 772 static int __videobuf_streamoff(struct videobuf_queue *q)
 773 {
 774         if (!q->streaming)
 775                 return -EINVAL;
 776
 777         videobuf_queue_cancel(q);
 778
 779         return 0;
 780 }
 781
 782 int videobuf_streamoff(struct videobuf_queue *q)
 783 {
 784         int retval;
 785
 786         videobuf_queue_lock(q);
 787         retval = __videobuf_streamoff(q);
 788         videobuf_queue_unlock(q);
 789
 790         return retval;
 791 }
 792 EXPORT_SYMBOL_GPL(videobuf_streamoff);
 793
 794 /* Locking: Caller holds q->vb_lock */
 795 static ssize_t videobuf_read_zerocopy(struct videobuf_queue *q,
 796                                       char __user *data,
 797                                       size_t count, loff_t *ppos)
 798 {
 799         enum v4l2_field field;
 800         unsigned long flags = 0;
 801         int retval;
 802
 803         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 804
 805         /* setup stuff */
 806         q->read_buf = videobuf_alloc_vb(q);
 807         if (NULL == q->read_buf)
 808                 return -ENOMEM;
 809
 810         q->read_buf->memory = V4L2_MEMORY_USERPTR;
 811         q->read_buf->baddr  = (unsigned long)data;
 812         q->read_buf->bsize  = count;
 813
 814         field = videobuf_next_field(q);
 815         retval = q->ops->buf_prepare(q, q->read_buf, field);
 816         if (0 != retval)
 817                 goto done;
 818
 819         /* start capture & wait */
 820         spin_lock_irqsave(q->irqlock, flags);
 821         q->ops->buf_queue(q, q->read_buf);
 822         spin_unlock_irqrestore(q->irqlock, flags);
 823         retval = videobuf_waiton(q, q->read_buf, 0, 0);
 824         if (0 == retval) {
 825                 CALL(q, sync, q, q->read_buf);
 826                 if (VIDEOBUF_ERROR == q->read_buf->state)
 827                         retval = -EIO;
 828                 else
 829                         retval = q->read_buf->size;
 830         }
 831
 832 done:
 833         /* cleanup */
 834         q->ops->buf_release(q, q->read_buf);
 835         kfree(q->read_buf);
 836         q->read_buf = NULL;
 837         return retval;
 838 }
 839
 840 static int __videobuf_copy_to_user(struct videobuf_queue *q,
 841                                    struct videobuf_buffer *buf,
 842                                    char __user *data, size_t count,
 843                                    int nonblocking)
 844 {
 845         void *vaddr = CALL(q, vaddr, buf);
 846
 847         /* copy to userspace */
 848         if (count > buf->size - q->read_off)
 849                 count = buf->size - q->read_off;
 850
 851         if (copy_to_user(data, vaddr + q->read_off, count))
 852                 return -EFAULT;
 853
 854         return count;
 855 }
 856
 857 static int __videobuf_copy_stream(struct videobuf_queue *q,
 858                                   struct videobuf_buffer *buf,
 859                                   char __user *data, size_t count, size_t pos,
 860                                   int vbihack, int nonblocking)
 861 {
 862         unsigned int *fc = CALL(q, vaddr, buf);
 863
 864         if (vbihack) {
 865                 /* dirty, undocumented hack -- pass the frame counter
 866                         * within the last four bytes of each vbi data block.
 867                         * We need that one to maintain backward compatibility
 868                         * to all vbi decoding software out there ... */
 869                 fc += (buf->size >> 2) - 1;
 870                 *fc = buf->field_count >> 1;
 871                 dprintk(1, "vbihack: %d\n", *fc);
 872         }
 873
 874         /* copy stuff using the common method */
 875         count = __videobuf_copy_to_user(q, buf, data, count, nonblocking);
 876
 877         if ((count == -EFAULT) && (pos == 0))
 878                 return -EFAULT;
 879
 880         return count;
 881 }
 882
 883 ssize_t videobuf_read_one(struct videobuf_queue *q,
 884                           char __user *data, size_t count, loff_t *ppos,
 885                           int nonblocking)
 886 {
 887         enum v4l2_field field;
 888         unsigned long flags = 0;
 889         unsigned size = 0, nbufs = 1;
 890         int retval;
 891
 892         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 893
 894         videobuf_queue_lock(q);
 895
 896         q->ops->buf_setup(q, &nbufs, &size);
 897
 898         if (NULL == q->read_buf  &&
 899             count >= size        &&
 900             !nonblocking) {
 901                 retval = videobuf_read_zerocopy(q, data, count, ppos);
 902                 if (retval >= 0  ||  retval == -EIO)
 903                         /* ok, all done */
 904                         goto done;
 905                 /* fallback to kernel bounce buffer on failures */
 906         }
 907
 908         if (NULL == q->read_buf) {
 909                 /* need to capture a new frame */
 910                 retval = -ENOMEM;
 911                 q->read_buf = videobuf_alloc_vb(q);
 912
 913                 dprintk(1, "video alloc=0x%p\n", q->read_buf);
 914                 if (NULL == q->read_buf)
 915                         goto done;
 916                 q->read_buf->memory = V4L2_MEMORY_USERPTR;
 917                 q->read_buf->bsize = count; /* preferred size */
 918                 field = videobuf_next_field(q);
 919                 retval = q->ops->buf_prepare(q, q->read_buf, field);
 920
 921                 if (0 != retval) {
 922                         kfree(q->read_buf);
 923                         q->read_buf = NULL;
 924                         goto done;
 925                 }
 926
 927                 spin_lock_irqsave(q->irqlock, flags);
 928                 q->ops->buf_queue(q, q->read_buf);
 929                 spin_unlock_irqrestore(q->irqlock, flags);
 930
 931                 q->read_off = 0;
 932         }
 933
 934         /* wait until capture is done */
 935         retval = videobuf_waiton(q, q->read_buf, nonblocking, 1);
 936         if (0 != retval)
 937                 goto done;
 938
 939         CALL(q, sync, q, q->read_buf);
 940
 941         if (VIDEOBUF_ERROR == q->read_buf->state) {
 942                 /* catch I/O errors */
 943                 q->ops->buf_release(q, q->read_buf);
 944                 kfree(q->read_buf);
 945                 q->read_buf = NULL;
 946                 retval = -EIO;
 947                 goto done;
 948         }
 949
 950         /* Copy to userspace */
 951         retval = __videobuf_copy_to_user(q, q->read_buf, data, count, nonblocking);
 952         if (retval < 0)
 953                 goto done;
 954
 955         q->read_off += retval;
 956         if (q->read_off == q->read_buf->size) {
 957                 /* all data copied, cleanup */
 958                 q->ops->buf_release(q, q->read_buf);
 959                 kfree(q->read_buf);
 960                 q->read_buf = NULL;
 961         }
 962
 963 done:
 964         videobuf_queue_unlock(q);
 965         return retval;
 966 }
 967 EXPORT_SYMBOL_GPL(videobuf_read_one);
 968
 969 /* Locking: Caller holds q->vb_lock */
 970 static int __videobuf_read_start(struct videobuf_queue *q)
 971 {
 972         enum v4l2_field field;
 973         unsigned long flags = 0;
 974         unsigned int count = 0, size = 0;
 975         int err, i;
 976
 977         q->ops->buf_setup(q, &count, &size);
 978         if (count < 2)
 979                 count = 2;
 980         if (count > VIDEO_MAX_FRAME)
 981                 count = VIDEO_MAX_FRAME;
 982         size = PAGE_ALIGN(size);
 983
 984         err = __videobuf_mmap_setup(q, count, size, V4L2_MEMORY_USERPTR);
 985         if (err < 0)
 986                 return err;
 987
 988         count = err;
 989
 990         for (i = 0; i < count; i++) {
 991                 field = videobuf_next_field(q);
 992                 err = q->ops->buf_prepare(q, q->bufs[i], field);
 993                 if (err)
 994                         return err;
 995                 list_add_tail(&q->bufs[i]->stream, &q->stream);
 996         }
 997         spin_lock_irqsave(q->irqlock, flags);
 998         for (i = 0; i < count; i++)
 999                 q->ops->buf_queue(q, q->bufs[i]);
1000         spin_unlock_irqrestore(q->irqlock, flags);
1001         q->reading = 1;
1002         return 0;
1003 }
1004
1005 static void __videobuf_read_stop(struct videobuf_queue *q)
1006 {
1007         int i;
1008
1009         videobuf_queue_cancel(q);
1010         __videobuf_free(q);
1011         INIT_LIST_HEAD(&q->stream);
1012         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
1013                 if (NULL == q->bufs[i])
1014                         continue;
1015                 kfree(q->bufs[i]);
1016                 q->bufs[i] = NULL;
1017         }
1018         q->read_buf = NULL;
1019 }
1020
1021 int videobuf_read_start(struct videobuf_queue *q)
1022 {
1023         int rc;
1024
1025         videobuf_queue_lock(q);
1026         rc = __videobuf_read_start(q);
1027         videobuf_queue_unlock(q);
1028
1029         return rc;
1030 }
1031 EXPORT_SYMBOL_GPL(videobuf_read_start);
1032
1033 void videobuf_read_stop(struct videobuf_queue *q)
1034 {
1035         videobuf_queue_lock(q);
1036         __videobuf_read_stop(q);
1037         videobuf_queue_unlock(q);
1038 }
1039 EXPORT_SYMBOL_GPL(videobuf_read_stop);
1040
1041 void videobuf_stop(struct videobuf_queue *q)
1042 {
1043         videobuf_queue_lock(q);
1044
1045         if (q->streaming)
1046                 __videobuf_streamoff(q);
1047
1048         if (q->reading)
1049                 __videobuf_read_stop(q);
1050
1051         videobuf_queue_unlock(q);
1052 }
1053 EXPORT_SYMBOL_GPL(videobuf_stop);
1054
1055 ssize_t videobuf_read_stream(struct videobuf_queue *q,
1056                              char __user *data, size_t count, loff_t *ppos,
1057                              int vbihack, int nonblocking)
1058 {
1059         int rc, retval;
1060         unsigned long flags = 0;
1061
1062         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
1063
1064         dprintk(2, "%s\n", __func__);
1065         videobuf_queue_lock(q);
1066         retval = -EBUSY;
1067         if (q->streaming)
1068                 goto done;
1069         if (!q->reading) {
1070                 retval = __videobuf_read_start(q);
1071                 if (retval < 0)
1072                         goto done;
1073         }
1074
1075         retval = 0;
1076         while (count > 0) {
1077                 /* get / wait for data */
1078                 if (NULL == q->read_buf) {
1079                         q->read_buf = list_entry(q->stream.next,
1080                                                  struct videobuf_buffer,
1081                                                  stream);
1082                         list_del(&q->read_buf->stream);
1083                         q->read_off = 0;
1084                 }
1085                 rc = videobuf_waiton(q, q->read_buf, nonblocking, 1);
1086                 if (rc < 0) {
1087                         if (0 == retval)
1088                                 retval = rc;
1089                         break;
1090                 }
1091
1092                 if (q->read_buf->state == VIDEOBUF_DONE) {
1093                         rc = __videobuf_copy_stream(q, q->read_buf, data + retval, count,
1094                                         retval, vbihack, nonblocking);
1095                         if (rc < 0) {
1096                                 retval = rc;
1097                                 break;
1098                         }
1099                         retval      += rc;
1100                         count       -= rc;
1101                         q->read_off += rc;
1102                 } else {
1103                         /* some error */
1104                         q->read_off = q->read_buf->size;
1105                         if (0 == retval)
1106                                 retval = -EIO;
1107                 }
1108
1109                 /* requeue buffer when done with copying */
1110                 if (q->read_off == q->read_buf->size) {
1111                         list_add_tail(&q->read_buf->stream,
1112                                       &q->stream);
1113                         spin_lock_irqsave(q->irqlock, flags);
1114                         q->ops->buf_queue(q, q->read_buf);
1115                         spin_unlock_irqrestore(q->irqlock, flags);
1116                         q->read_buf = NULL;
1117                 }
1118                 if (retval < 0)
1119                         break;
1120         }
1121
1122 done:
1123         videobuf_queue_unlock(q);
1124         return retval;
1125 }
1126 EXPORT_SYMBOL_GPL(videobuf_read_stream);
1127
1128 unsigned int videobuf_poll_stream(struct file *file,
1129                                   struct videobuf_queue *q,
1130                                   poll_table *wait)
1131 {
1132         struct videobuf_buffer *buf = NULL;
1133         unsigned int rc = 0;
1134
1135         videobuf_queue_lock(q);
1136         if (q->streaming) {
1137                 if (!list_empty(&q->stream))
1138                         buf = list_entry(q->stream.next,
1139                                          struct videobuf_buffer, stream);
1140         } else {
1141                 if (!q->reading)
1142                         __videobuf_read_start(q);
1143                 if (!q->reading) {
1144                         rc = POLLERR;
1145                 } else if (NULL == q->read_buf) {
1146                         q->read_buf = list_entry(q->stream.next,
1147                                                  struct videobuf_buffer,
1148                                                  stream);
1149                         list_del(&q->read_buf->stream);
1150                         q->read_off = 0;
1151                 }
1152                 buf = q->read_buf;
1153         }
1154         if (!buf)
1155                 rc = POLLERR;
1156
1157         if (0 == rc) {
1158                 poll_wait(file, &buf->done, wait);
1159                 if (buf->state == VIDEOBUF_DONE ||
1160                     buf->state == VIDEOBUF_ERROR) {
1161                         switch (q->type) {
1162                         case V4L2_BUF_TYPE_VIDEO_OUTPUT:
1163                         case V4L2_BUF_TYPE_VBI_OUTPUT:
1164                         case V4L2_BUF_TYPE_SLICED_VBI_OUTPUT:
1165                                 rc = POLLOUT | POLLWRNORM;
1166                                 break;
1167                         default:
1168                                 rc = POLLIN | POLLRDNORM;
1169                                 break;
1170                         }
1171                 }
1172         }
1173         videobuf_queue_unlock(q);
1174         return rc;
1175 }
1176 EXPORT_SYMBOL_GPL(videobuf_poll_stream);
1177
1178 int videobuf_mmap_mapper(struct videobuf_queue *q, struct vm_area_struct *vma)
1179 {
1180         int rc = -EINVAL;
1181         int i;
1182
1183         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
1184
1185         if (!(vma->vm_flags & VM_WRITE) || !(vma->vm_flags & VM_SHARED)) {
1186                 dprintk(1, "mmap appl bug: PROT_WRITE and MAP_SHARED are required\n");
1187                 return -EINVAL;
1188         }
1189
1190         videobuf_queue_lock(q);
1191         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
1192                 struct videobuf_buffer *buf = q->bufs[i];
1193
1194                 if (buf && buf->memory == V4L2_MEMORY_MMAP &&
1195                                 buf->boff == (vma->vm_pgoff << PAGE_SHIFT)) {
1196                         rc = CALL(q, mmap_mapper, q, buf, vma);
1197                         break;
1198                 }
1199         }
1200         videobuf_queue_unlock(q);
1201
1202         return rc;
1203 }
1204 EXPORT_SYMBOL_GPL(videobuf_mmap_mapper);