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

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * generic helper functions for handling video4linux capture buffers
   4  *
   5  * (c) 2007 Mauro Carvalho Chehab, <mchehab@kernel.org>
   6  *
   7  * Highly based on video-buf written originally by:
   8  * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
   9  * (c) 2006 Mauro Carvalho Chehab, <mchehab@kernel.org>
  10  * (c) 2006 Ted Walther and John Sokol
  11  */
  12
  13 #include <linux/init.h>
  14 #include <linux/module.h>
  15 #include <linux/moduleparam.h>
  16 #include <linux/mm.h>
  17 #include <linux/sched.h>
  18 #include <linux/slab.h>
  19 #include <linux/interrupt.h>
  20
  21 #include <media/videobuf-core.h>
  22 #include <media/v4l2-common.h>
  23
  24 #define MAGIC_BUFFER 0x20070728
  25 #define MAGIC_CHECK(is, should)                                         \
  26         do {                                                            \
  27                 if (unlikely((is) != (should))) {                       \
  28                         printk(KERN_ERR                                 \
  29                                 "magic mismatch: %x (expected %x)\n",   \
  30                                         is, should);                    \
  31                         BUG();                                          \
  32                 }                                                       \
  33         } while (0)
  34
  35 static int debug;
  36 module_param(debug, int, 0644);
  37
  38 MODULE_DESCRIPTION("helper module to manage video4linux buffers");
  39 MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@kernel.org>");
  40 MODULE_LICENSE("GPL");
  41
  42 #define dprintk(level, fmt, arg...)                                     \
  43         do {                                                            \
  44                 if (debug >= level)                                     \
  45                         printk(KERN_DEBUG "vbuf: " fmt, ## arg);        \
  46         } while (0)
  47
  48 /* --------------------------------------------------------------------- */
  49
  50 #define CALL(q, f, arg...)                                              \
  51         ((q->int_ops->f) ? q->int_ops->f(arg) : 0)
  52 #define CALLPTR(q, f, arg...)                                           \
  53         ((q->int_ops->f) ? q->int_ops->f(arg) : NULL)
  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 state_neither_active_nor_queued(struct videobuf_queue *q,
  77                                            struct videobuf_buffer *vb)
  78 {
  79         unsigned long flags;
  80         bool rc;
  81
  82         spin_lock_irqsave(q->irqlock, flags);
  83         rc = vb->state != VIDEOBUF_ACTIVE && vb->state != VIDEOBUF_QUEUED;
  84         spin_unlock_irqrestore(q->irqlock, flags);
  85         return rc;
  86 };
  87
  88 int videobuf_waiton(struct videobuf_queue *q, struct videobuf_buffer *vb,
  89                 int non_blocking, int intr)
  90 {
  91         bool is_ext_locked;
  92         int ret = 0;
  93
  94         MAGIC_CHECK(vb->magic, MAGIC_BUFFER);
  95
  96         if (non_blocking) {
  97                 if (state_neither_active_nor_queued(q, vb))
  98                         return 0;
  99                 return -EAGAIN;
 100         }
 101
 102         is_ext_locked = q->ext_lock && mutex_is_locked(q->ext_lock);
 103
 104         /* Release vdev lock to prevent this wait from blocking outside access to
 105            the device. */
 106         if (is_ext_locked)
 107                 mutex_unlock(q->ext_lock);
 108         if (intr)
 109                 ret = wait_event_interruptible(vb->done,
 110                                         state_neither_active_nor_queued(q, vb));
 111         else
 112                 wait_event(vb->done, state_neither_active_nor_queued(q, vb));
 113         /* Relock */
 114         if (is_ext_locked)
 115                 mutex_lock(q->ext_lock);
 116
 117         return ret;
 118 }
 119 EXPORT_SYMBOL_GPL(videobuf_waiton);
 120
 121 int videobuf_iolock(struct videobuf_queue *q, struct videobuf_buffer *vb,
 122                     struct v4l2_framebuffer *fbuf)
 123 {
 124         MAGIC_CHECK(vb->magic, MAGIC_BUFFER);
 125         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 126
 127         return CALL(q, iolock, q, vb, fbuf);
 128 }
 129 EXPORT_SYMBOL_GPL(videobuf_iolock);
 130
 131 void *videobuf_queue_to_vaddr(struct videobuf_queue *q,
 132                               struct videobuf_buffer *buf)
 133 {
 134         if (q->int_ops->vaddr)
 135                 return q->int_ops->vaddr(buf);
 136         return NULL;
 137 }
 138 EXPORT_SYMBOL_GPL(videobuf_queue_to_vaddr);
 139
 140 /* --------------------------------------------------------------------- */
 141
 142
 143 void videobuf_queue_core_init(struct videobuf_queue *q,
 144                          const struct videobuf_queue_ops *ops,
 145                          struct device *dev,
 146                          spinlock_t *irqlock,
 147                          enum v4l2_buf_type type,
 148                          enum v4l2_field field,
 149                          unsigned int msize,
 150                          void *priv,
 151                          struct videobuf_qtype_ops *int_ops,
 152                          struct mutex *ext_lock)
 153 {
 154         BUG_ON(!q);
 155         memset(q, 0, sizeof(*q));
 156         q->irqlock   = irqlock;
 157         q->ext_lock  = ext_lock;
 158         q->dev       = dev;
 159         q->type      = type;
 160         q->field     = field;
 161         q->msize     = msize;
 162         q->ops       = ops;
 163         q->priv_data = priv;
 164         q->int_ops   = int_ops;
 165
 166         /* All buffer operations are mandatory */
 167         BUG_ON(!q->ops->buf_setup);
 168         BUG_ON(!q->ops->buf_prepare);
 169         BUG_ON(!q->ops->buf_queue);
 170         BUG_ON(!q->ops->buf_release);
 171
 172         /* Lock is mandatory for queue_cancel to work */
 173         BUG_ON(!irqlock);
 174
 175         /* Having implementations for abstract methods are mandatory */
 176         BUG_ON(!q->int_ops);
 177
 178         mutex_init(&q->vb_lock);
 179         init_waitqueue_head(&q->wait);
 180         INIT_LIST_HEAD(&q->stream);
 181 }
 182 EXPORT_SYMBOL_GPL(videobuf_queue_core_init);
 183
 184 /* Locking: Only usage in bttv unsafe find way to remove */
 185 int videobuf_queue_is_busy(struct videobuf_queue *q)
 186 {
 187         int i;
 188
 189         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 190
 191         if (q->streaming) {
 192                 dprintk(1, "busy: streaming active\n");
 193                 return 1;
 194         }
 195         if (q->reading) {
 196                 dprintk(1, "busy: pending read #1\n");
 197                 return 1;
 198         }
 199         if (q->read_buf) {
 200                 dprintk(1, "busy: pending read #2\n");
 201                 return 1;
 202         }
 203         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 204                 if (NULL == q->bufs[i])
 205                         continue;
 206                 if (q->bufs[i]->map) {
 207                         dprintk(1, "busy: buffer #%d mapped\n", i);
 208                         return 1;
 209                 }
 210                 if (q->bufs[i]->state == VIDEOBUF_QUEUED) {
 211                         dprintk(1, "busy: buffer #%d queued\n", i);
 212                         return 1;
 213                 }
 214                 if (q->bufs[i]->state == VIDEOBUF_ACTIVE) {
 215                         dprintk(1, "busy: buffer #%d active\n", i);
 216                         return 1;
 217                 }
 218         }
 219         return 0;
 220 }
 221 EXPORT_SYMBOL_GPL(videobuf_queue_is_busy);
 222
 223 /*
 224  * __videobuf_free() - free all the buffers and their control structures
 225  *
 226  * This function can only be called if streaming/reading is off, i.e. no buffers
 227  * are under control of the driver.
 228  */
 229 /* Locking: Caller holds q->vb_lock */
 230 static int __videobuf_free(struct videobuf_queue *q)
 231 {
 232         int i;
 233
 234         dprintk(1, "%s\n", __func__);
 235         if (!q)
 236                 return 0;
 237
 238         if (q->streaming || q->reading) {
 239                 dprintk(1, "Cannot free buffers when streaming or reading\n");
 240                 return -EBUSY;
 241         }
 242
 243         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 244
 245         for (i = 0; i < VIDEO_MAX_FRAME; i++)
 246                 if (q->bufs[i] && q->bufs[i]->map) {
 247                         dprintk(1, "Cannot free mmapped buffers\n");
 248                         return -EBUSY;
 249                 }
 250
 251         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 252                 if (NULL == q->bufs[i])
 253                         continue;
 254                 q->ops->buf_release(q, q->bufs[i]);
 255                 kfree(q->bufs[i]);
 256                 q->bufs[i] = NULL;
 257         }
 258
 259         return 0;
 260 }
 261
 262 /* Locking: Caller holds q->vb_lock */
 263 void videobuf_queue_cancel(struct videobuf_queue *q)
 264 {
 265         unsigned long flags = 0;
 266         int i;
 267
 268         q->streaming = 0;
 269         q->reading  = 0;
 270         wake_up_interruptible_sync(&q->wait);
 271
 272         /* remove queued buffers from list */
 273         spin_lock_irqsave(q->irqlock, flags);
 274         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 275                 if (NULL == q->bufs[i])
 276                         continue;
 277                 if (q->bufs[i]->state == VIDEOBUF_QUEUED) {
 278                         list_del(&q->bufs[i]->queue);
 279                         q->bufs[i]->state = VIDEOBUF_ERROR;
 280                         wake_up_all(&q->bufs[i]->done);
 281                 }
 282         }
 283         spin_unlock_irqrestore(q->irqlock, flags);
 284
 285         /* free all buffers + clear queue */
 286         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 287                 if (NULL == q->bufs[i])
 288                         continue;
 289                 q->ops->buf_release(q, q->bufs[i]);
 290         }
 291         INIT_LIST_HEAD(&q->stream);
 292 }
 293 EXPORT_SYMBOL_GPL(videobuf_queue_cancel);
 294
 295 /* --------------------------------------------------------------------- */
 296
 297 /* Locking: Caller holds q->vb_lock */
 298 enum v4l2_field videobuf_next_field(struct videobuf_queue *q)
 299 {
 300         enum v4l2_field field = q->field;
 301
 302         BUG_ON(V4L2_FIELD_ANY == field);
 303
 304         if (V4L2_FIELD_ALTERNATE == field) {
 305                 if (V4L2_FIELD_TOP == q->last) {
 306                         field   = V4L2_FIELD_BOTTOM;
 307                         q->last = V4L2_FIELD_BOTTOM;
 308                 } else {
 309                         field   = V4L2_FIELD_TOP;
 310                         q->last = V4L2_FIELD_TOP;
 311                 }
 312         }
 313         return field;
 314 }
 315 EXPORT_SYMBOL_GPL(videobuf_next_field);
 316
 317 /* Locking: Caller holds q->vb_lock */
 318 static void videobuf_status(struct videobuf_queue *q, struct v4l2_buffer *b,
 319                             struct videobuf_buffer *vb, enum v4l2_buf_type type)
 320 {
 321         MAGIC_CHECK(vb->magic, MAGIC_BUFFER);
 322         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 323
 324         b->index    = vb->i;
 325         b->type     = type;
 326
 327         b->memory   = vb->memory;
 328         switch (b->memory) {
 329         case V4L2_MEMORY_MMAP:
 330                 b->m.offset  = vb->boff;
 331                 b->length    = vb->bsize;
 332                 break;
 333         case V4L2_MEMORY_USERPTR:
 334                 b->m.userptr = vb->baddr;
 335                 b->length    = vb->bsize;
 336                 break;
 337         case V4L2_MEMORY_OVERLAY:
 338                 b->m.offset  = vb->boff;
 339                 break;
 340         case V4L2_MEMORY_DMABUF:
 341                 /* DMABUF is not handled in videobuf framework */
 342                 break;
 343         }
 344
 345         b->flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
 346         if (vb->map)
 347                 b->flags |= V4L2_BUF_FLAG_MAPPED;
 348
 349         switch (vb->state) {
 350         case VIDEOBUF_PREPARED:
 351         case VIDEOBUF_QUEUED:
 352         case VIDEOBUF_ACTIVE:
 353                 b->flags |= V4L2_BUF_FLAG_QUEUED;
 354                 break;
 355         case VIDEOBUF_ERROR:
 356                 b->flags |= V4L2_BUF_FLAG_ERROR;
 357                 fallthrough;
 358         case VIDEOBUF_DONE:
 359                 b->flags |= V4L2_BUF_FLAG_DONE;
 360                 break;
 361         case VIDEOBUF_NEEDS_INIT:
 362         case VIDEOBUF_IDLE:
 363                 /* nothing */
 364                 break;
 365         }
 366
 367         b->field     = vb->field;
 368         v4l2_buffer_set_timestamp(b, 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]->memory = memory;
 406                 q->bufs[i]->bsize  = bsize;
 407                 switch (memory) {
 408                 case V4L2_MEMORY_MMAP:
 409                         q->bufs[i]->boff = PAGE_ALIGN(bsize) * i;
 410                         break;
 411                 case V4L2_MEMORY_USERPTR:
 412                 case V4L2_MEMORY_OVERLAY:
 413                 case V4L2_MEMORY_DMABUF:
 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->memory != V4L2_MEMORY_MMAP     &&
 447             req->memory != V4L2_MEMORY_USERPTR  &&
 448             req->memory != V4L2_MEMORY_OVERLAY) {
 449                 dprintk(1, "reqbufs: memory type invalid\n");
 450                 return -EINVAL;
 451         }
 452
 453         videobuf_queue_lock(q);
 454         if (req->type != q->type) {
 455                 dprintk(1, "reqbufs: queue type invalid\n");
 456                 retval = -EINVAL;
 457                 goto done;
 458         }
 459
 460         if (q->streaming) {
 461                 dprintk(1, "reqbufs: streaming already exists\n");
 462                 retval = -EBUSY;
 463                 goto done;
 464         }
 465         if (!list_empty(&q->stream)) {
 466                 dprintk(1, "reqbufs: stream running\n");
 467                 retval = -EBUSY;
 468                 goto done;
 469         }
 470
 471         if (req->count == 0) {
 472                 dprintk(1, "reqbufs: count invalid (%d)\n", req->count);
 473                 retval = __videobuf_free(q);
 474                 goto done;
 475         }
 476
 477         count = req->count;
 478         if (count > VIDEO_MAX_FRAME)
 479                 count = VIDEO_MAX_FRAME;
 480         size = 0;
 481         q->ops->buf_setup(q, &count, &size);
 482         dprintk(1, "reqbufs: bufs=%d, size=0x%x [%u pages total]\n",
 483                 count, size,
 484                 (unsigned int)((count * PAGE_ALIGN(size)) >> PAGE_SHIFT));
 485
 486         retval = __videobuf_mmap_setup(q, count, size, req->memory);
 487         if (retval < 0) {
 488                 dprintk(1, "reqbufs: mmap setup returned %d\n", retval);
 489                 goto done;
 490         }
 491
 492         req->count = retval;
 493         retval = 0;
 494
 495  done:
 496         videobuf_queue_unlock(q);
 497         return retval;
 498 }
 499 EXPORT_SYMBOL_GPL(videobuf_reqbufs);
 500
 501 int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b)
 502 {
 503         int ret = -EINVAL;
 504
 505         videobuf_queue_lock(q);
 506         if (unlikely(b->type != q->type)) {
 507                 dprintk(1, "querybuf: Wrong type.\n");
 508                 goto done;
 509         }
 510         if (unlikely(b->index >= VIDEO_MAX_FRAME)) {
 511                 dprintk(1, "querybuf: index out of range.\n");
 512                 goto done;
 513         }
 514         if (unlikely(NULL == q->bufs[b->index])) {
 515                 dprintk(1, "querybuf: buffer is null.\n");
 516                 goto done;
 517         }
 518
 519         videobuf_status(q, b, q->bufs[b->index], q->type);
 520
 521         ret = 0;
 522 done:
 523         videobuf_queue_unlock(q);
 524         return ret;
 525 }
 526 EXPORT_SYMBOL_GPL(videobuf_querybuf);
 527
 528 int videobuf_qbuf(struct videobuf_queue *q, struct v4l2_buffer *b)
 529 {
 530         struct videobuf_buffer *buf;
 531         enum v4l2_field field;
 532         unsigned long flags = 0;
 533         int retval;
 534
 535         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 536
 537         if (b->memory == V4L2_MEMORY_MMAP)
 538                 mmap_read_lock(current->mm);
 539
 540         videobuf_queue_lock(q);
 541         retval = -EBUSY;
 542         if (q->reading) {
 543                 dprintk(1, "qbuf: Reading running...\n");
 544                 goto done;
 545         }
 546         retval = -EINVAL;
 547         if (b->type != q->type) {
 548                 dprintk(1, "qbuf: Wrong type.\n");
 549                 goto done;
 550         }
 551         if (b->index >= VIDEO_MAX_FRAME) {
 552                 dprintk(1, "qbuf: index out of range.\n");
 553                 goto done;
 554         }
 555         buf = q->bufs[b->index];
 556         if (NULL == buf) {
 557                 dprintk(1, "qbuf: buffer is null.\n");
 558                 goto done;
 559         }
 560         MAGIC_CHECK(buf->magic, MAGIC_BUFFER);
 561         if (buf->memory != b->memory) {
 562                 dprintk(1, "qbuf: memory type is wrong.\n");
 563                 goto done;
 564         }
 565         if (buf->state != VIDEOBUF_NEEDS_INIT && buf->state != VIDEOBUF_IDLE) {
 566                 dprintk(1, "qbuf: buffer is already queued or active.\n");
 567                 goto done;
 568         }
 569
 570         switch (b->memory) {
 571         case V4L2_MEMORY_MMAP:
 572                 if (0 == buf->baddr) {
 573                         dprintk(1, "qbuf: mmap requested but buffer addr is zero!\n");
 574                         goto done;
 575                 }
 576                 if (q->type == V4L2_BUF_TYPE_VIDEO_OUTPUT
 577                     || q->type == V4L2_BUF_TYPE_VBI_OUTPUT
 578                     || q->type == V4L2_BUF_TYPE_SLICED_VBI_OUTPUT
 579                     || q->type == V4L2_BUF_TYPE_SDR_OUTPUT) {
 580                         buf->size = b->bytesused;
 581                         buf->field = b->field;
 582                         buf->ts = v4l2_buffer_get_timestamp(b);
 583                 }
 584                 break;
 585         case V4L2_MEMORY_USERPTR:
 586                 if (b->length < buf->bsize) {
 587                         dprintk(1, "qbuf: buffer length is not enough\n");
 588                         goto done;
 589                 }
 590                 if (VIDEOBUF_NEEDS_INIT != buf->state &&
 591                     buf->baddr != b->m.userptr)
 592                         q->ops->buf_release(q, buf);
 593                 buf->baddr = b->m.userptr;
 594                 break;
 595         case V4L2_MEMORY_OVERLAY:
 596                 buf->boff = b->m.offset;
 597                 break;
 598         default:
 599                 dprintk(1, "qbuf: wrong memory type\n");
 600                 goto done;
 601         }
 602
 603         dprintk(1, "qbuf: requesting next field\n");
 604         field = videobuf_next_field(q);
 605         retval = q->ops->buf_prepare(q, buf, field);
 606         if (0 != retval) {
 607                 dprintk(1, "qbuf: buffer_prepare returned %d\n", retval);
 608                 goto done;
 609         }
 610
 611         list_add_tail(&buf->stream, &q->stream);
 612         if (q->streaming) {
 613                 spin_lock_irqsave(q->irqlock, flags);
 614                 q->ops->buf_queue(q, buf);
 615                 spin_unlock_irqrestore(q->irqlock, flags);
 616         }
 617         dprintk(1, "qbuf: succeeded\n");
 618         retval = 0;
 619         wake_up_interruptible_sync(&q->wait);
 620
 621 done:
 622         videobuf_queue_unlock(q);
 623
 624         if (b->memory == V4L2_MEMORY_MMAP)
 625                 mmap_read_unlock(current->mm);
 626
 627         return retval;
 628 }
 629 EXPORT_SYMBOL_GPL(videobuf_qbuf);
 630
 631 /* Locking: Caller holds q->vb_lock */
 632 static int stream_next_buffer_check_queue(struct videobuf_queue *q, int noblock)
 633 {
 634         int retval;
 635
 636 checks:
 637         if (!q->streaming) {
 638                 dprintk(1, "next_buffer: Not streaming\n");
 639                 retval = -EINVAL;
 640                 goto done;
 641         }
 642
 643         if (list_empty(&q->stream)) {
 644                 if (noblock) {
 645                         retval = -EAGAIN;
 646                         dprintk(2, "next_buffer: no buffers to dequeue\n");
 647                         goto done;
 648                 } else {
 649                         dprintk(2, "next_buffer: waiting on buffer\n");
 650
 651                         /* Drop lock to avoid deadlock with qbuf */
 652                         videobuf_queue_unlock(q);
 653
 654                         /* Checking list_empty and streaming is safe without
 655                          * locks because we goto checks to validate while
 656                          * holding locks before proceeding */
 657                         retval = wait_event_interruptible(q->wait,
 658                                 !list_empty(&q->stream) || !q->streaming);
 659                         videobuf_queue_lock(q);
 660
 661                         if (retval)
 662                                 goto done;
 663
 664                         goto checks;
 665                 }
 666         }
 667
 668         retval = 0;
 669
 670 done:
 671         return retval;
 672 }
 673
 674 /* Locking: Caller holds q->vb_lock */
 675 static int stream_next_buffer(struct videobuf_queue *q,
 676                         struct videobuf_buffer **vb, int nonblocking)
 677 {
 678         int retval;
 679         struct videobuf_buffer *buf = NULL;
 680
 681         retval = stream_next_buffer_check_queue(q, nonblocking);
 682         if (retval)
 683                 goto done;
 684
 685         buf = list_entry(q->stream.next, struct videobuf_buffer, stream);
 686         retval = videobuf_waiton(q, buf, nonblocking, 1);
 687         if (retval < 0)
 688                 goto done;
 689
 690         *vb = buf;
 691 done:
 692         return retval;
 693 }
 694
 695 int videobuf_dqbuf(struct videobuf_queue *q,
 696                    struct v4l2_buffer *b, int nonblocking)
 697 {
 698         struct videobuf_buffer *buf = NULL;
 699         int retval;
 700
 701         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 702
 703         memset(b, 0, sizeof(*b));
 704         videobuf_queue_lock(q);
 705
 706         retval = stream_next_buffer(q, &buf, nonblocking);
 707         if (retval < 0) {
 708                 dprintk(1, "dqbuf: next_buffer error: %i\n", retval);
 709                 goto done;
 710         }
 711
 712         switch (buf->state) {
 713         case VIDEOBUF_ERROR:
 714                 dprintk(1, "dqbuf: state is error\n");
 715                 break;
 716         case VIDEOBUF_DONE:
 717                 dprintk(1, "dqbuf: state is done\n");
 718                 break;
 719         default:
 720                 dprintk(1, "dqbuf: state invalid\n");
 721                 retval = -EINVAL;
 722                 goto done;
 723         }
 724         CALL(q, sync, q, buf);
 725         videobuf_status(q, b, buf, q->type);
 726         list_del(&buf->stream);
 727         buf->state = VIDEOBUF_IDLE;
 728         b->flags &= ~V4L2_BUF_FLAG_DONE;
 729 done:
 730         videobuf_queue_unlock(q);
 731         return retval;
 732 }
 733 EXPORT_SYMBOL_GPL(videobuf_dqbuf);
 734
 735 int videobuf_streamon(struct videobuf_queue *q)
 736 {
 737         struct videobuf_buffer *buf;
 738         unsigned long flags = 0;
 739         int retval;
 740
 741         videobuf_queue_lock(q);
 742         retval = -EBUSY;
 743         if (q->reading)
 744                 goto done;
 745         retval = 0;
 746         if (q->streaming)
 747                 goto done;
 748         q->streaming = 1;
 749         spin_lock_irqsave(q->irqlock, flags);
 750         list_for_each_entry(buf, &q->stream, stream)
 751                 if (buf->state == VIDEOBUF_PREPARED)
 752                         q->ops->buf_queue(q, buf);
 753         spin_unlock_irqrestore(q->irqlock, flags);
 754
 755         wake_up_interruptible_sync(&q->wait);
 756 done:
 757         videobuf_queue_unlock(q);
 758         return retval;
 759 }
 760 EXPORT_SYMBOL_GPL(videobuf_streamon);
 761
 762 /* Locking: Caller holds q->vb_lock */
 763 static int __videobuf_streamoff(struct videobuf_queue *q)
 764 {
 765         if (!q->streaming)
 766                 return -EINVAL;
 767
 768         videobuf_queue_cancel(q);
 769
 770         return 0;
 771 }
 772
 773 int videobuf_streamoff(struct videobuf_queue *q)
 774 {
 775         int retval;
 776
 777         videobuf_queue_lock(q);
 778         retval = __videobuf_streamoff(q);
 779         videobuf_queue_unlock(q);
 780
 781         return retval;
 782 }
 783 EXPORT_SYMBOL_GPL(videobuf_streamoff);
 784
 785 /* Locking: Caller holds q->vb_lock */
 786 static ssize_t videobuf_read_zerocopy(struct videobuf_queue *q,
 787                                       char __user *data,
 788                                       size_t count, loff_t *ppos)
 789 {
 790         enum v4l2_field field;
 791         unsigned long flags = 0;
 792         int retval;
 793
 794         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 795
 796         /* setup stuff */
 797         q->read_buf = videobuf_alloc_vb(q);
 798         if (NULL == q->read_buf)
 799                 return -ENOMEM;
 800
 801         q->read_buf->memory = V4L2_MEMORY_USERPTR;
 802         q->read_buf->baddr  = (unsigned long)data;
 803         q->read_buf->bsize  = count;
 804
 805         field = videobuf_next_field(q);
 806         retval = q->ops->buf_prepare(q, q->read_buf, field);
 807         if (0 != retval)
 808                 goto done;
 809
 810         /* start capture & wait */
 811         spin_lock_irqsave(q->irqlock, flags);
 812         q->ops->buf_queue(q, q->read_buf);
 813         spin_unlock_irqrestore(q->irqlock, flags);
 814         retval = videobuf_waiton(q, q->read_buf, 0, 0);
 815         if (0 == retval) {
 816                 CALL(q, sync, q, q->read_buf);
 817                 if (VIDEOBUF_ERROR == q->read_buf->state)
 818                         retval = -EIO;
 819                 else
 820                         retval = q->read_buf->size;
 821         }
 822
 823 done:
 824         /* cleanup */
 825         q->ops->buf_release(q, q->read_buf);
 826         kfree(q->read_buf);
 827         q->read_buf = NULL;
 828         return retval;
 829 }
 830
 831 static int __videobuf_copy_to_user(struct videobuf_queue *q,
 832                                    struct videobuf_buffer *buf,
 833                                    char __user *data, size_t count,
 834                                    int nonblocking)
 835 {
 836         void *vaddr = CALLPTR(q, vaddr, buf);
 837
 838         /* copy to userspace */
 839         if (count > buf->size - q->read_off)
 840                 count = buf->size - q->read_off;
 841
 842         if (copy_to_user(data, vaddr + q->read_off, count))
 843                 return -EFAULT;
 844
 845         return count;
 846 }
 847
 848 static int __videobuf_copy_stream(struct videobuf_queue *q,
 849                                   struct videobuf_buffer *buf,
 850                                   char __user *data, size_t count, size_t pos,
 851                                   int vbihack, int nonblocking)
 852 {
 853         unsigned int *fc = CALLPTR(q, vaddr, buf);
 854
 855         if (vbihack) {
 856                 /* dirty, undocumented hack -- pass the frame counter
 857                         * within the last four bytes of each vbi data block.
 858                         * We need that one to maintain backward compatibility
 859                         * to all vbi decoding software out there ... */
 860                 fc += (buf->size >> 2) - 1;
 861                 *fc = buf->field_count >> 1;
 862                 dprintk(1, "vbihack: %d\n", *fc);
 863         }
 864
 865         /* copy stuff using the common method */
 866         count = __videobuf_copy_to_user(q, buf, data, count, nonblocking);
 867
 868         if ((count == -EFAULT) && (pos == 0))
 869                 return -EFAULT;
 870
 871         return count;
 872 }
 873
 874 ssize_t videobuf_read_one(struct videobuf_queue *q,
 875                           char __user *data, size_t count, loff_t *ppos,
 876                           int nonblocking)
 877 {
 878         enum v4l2_field field;
 879         unsigned long flags = 0;
 880         unsigned size = 0, nbufs = 1;
 881         int retval;
 882
 883         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 884
 885         videobuf_queue_lock(q);
 886
 887         q->ops->buf_setup(q, &nbufs, &size);
 888
 889         if (NULL == q->read_buf  &&
 890             count >= size        &&
 891             !nonblocking) {
 892                 retval = videobuf_read_zerocopy(q, data, count, ppos);
 893                 if (retval >= 0  ||  retval == -EIO)
 894                         /* ok, all done */
 895                         goto done;
 896                 /* fallback to kernel bounce buffer on failures */
 897         }
 898
 899         if (NULL == q->read_buf) {
 900                 /* need to capture a new frame */
 901                 retval = -ENOMEM;
 902                 q->read_buf = videobuf_alloc_vb(q);
 903
 904                 dprintk(1, "video alloc=0x%p\n", q->read_buf);
 905                 if (NULL == q->read_buf)
 906                         goto done;
 907                 q->read_buf->memory = V4L2_MEMORY_USERPTR;
 908                 q->read_buf->bsize = count; /* preferred size */
 909                 field = videobuf_next_field(q);
 910                 retval = q->ops->buf_prepare(q, q->read_buf, field);
 911
 912                 if (0 != retval) {
 913                         kfree(q->read_buf);
 914                         q->read_buf = NULL;
 915                         goto done;
 916                 }
 917
 918                 spin_lock_irqsave(q->irqlock, flags);
 919                 q->ops->buf_queue(q, q->read_buf);
 920                 spin_unlock_irqrestore(q->irqlock, flags);
 921
 922                 q->read_off = 0;
 923         }
 924
 925         /* wait until capture is done */
 926         retval = videobuf_waiton(q, q->read_buf, nonblocking, 1);
 927         if (0 != retval)
 928                 goto done;
 929
 930         CALL(q, sync, q, q->read_buf);
 931
 932         if (VIDEOBUF_ERROR == q->read_buf->state) {
 933                 /* catch I/O errors */
 934                 q->ops->buf_release(q, q->read_buf);
 935                 kfree(q->read_buf);
 936                 q->read_buf = NULL;
 937                 retval = -EIO;
 938                 goto done;
 939         }
 940
 941         /* Copy to userspace */
 942         retval = __videobuf_copy_to_user(q, q->read_buf, data, count, nonblocking);
 943         if (retval < 0)
 944                 goto done;
 945
 946         q->read_off += retval;
 947         if (q->read_off == q->read_buf->size) {
 948                 /* all data copied, cleanup */
 949                 q->ops->buf_release(q, q->read_buf);
 950                 kfree(q->read_buf);
 951                 q->read_buf = NULL;
 952         }
 953
 954 done:
 955         videobuf_queue_unlock(q);
 956         return retval;
 957 }
 958 EXPORT_SYMBOL_GPL(videobuf_read_one);
 959
 960 /* Locking: Caller holds q->vb_lock */
 961 static int __videobuf_read_start(struct videobuf_queue *q)
 962 {
 963         enum v4l2_field field;
 964         unsigned long flags = 0;
 965         unsigned int count = 0, size = 0;
 966         int err, i;
 967
 968         q->ops->buf_setup(q, &count, &size);
 969         if (count < 2)
 970                 count = 2;
 971         if (count > VIDEO_MAX_FRAME)
 972                 count = VIDEO_MAX_FRAME;
 973         size = PAGE_ALIGN(size);
 974
 975         err = __videobuf_mmap_setup(q, count, size, V4L2_MEMORY_USERPTR);
 976         if (err < 0)
 977                 return err;
 978
 979         count = err;
 980
 981         for (i = 0; i < count; i++) {
 982                 field = videobuf_next_field(q);
 983                 err = q->ops->buf_prepare(q, q->bufs[i], field);
 984                 if (err)
 985                         return err;
 986                 list_add_tail(&q->bufs[i]->stream, &q->stream);
 987         }
 988         spin_lock_irqsave(q->irqlock, flags);
 989         for (i = 0; i < count; i++)
 990                 q->ops->buf_queue(q, q->bufs[i]);
 991         spin_unlock_irqrestore(q->irqlock, flags);
 992         q->reading = 1;
 993         return 0;
 994 }
 995
 996 static void __videobuf_read_stop(struct videobuf_queue *q)
 997 {
 998         int i;
 999
1000         videobuf_queue_cancel(q);
1001         __videobuf_free(q);
1002         INIT_LIST_HEAD(&q->stream);
1003         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
1004                 if (NULL == q->bufs[i])
1005                         continue;
1006                 kfree(q->bufs[i]);
1007                 q->bufs[i] = NULL;
1008         }
1009         q->read_buf = NULL;
1010 }
1011
1012 int videobuf_read_start(struct videobuf_queue *q)
1013 {
1014         int rc;
1015
1016         videobuf_queue_lock(q);
1017         rc = __videobuf_read_start(q);
1018         videobuf_queue_unlock(q);
1019
1020         return rc;
1021 }
1022 EXPORT_SYMBOL_GPL(videobuf_read_start);
1023
1024 void videobuf_read_stop(struct videobuf_queue *q)
1025 {
1026         videobuf_queue_lock(q);
1027         __videobuf_read_stop(q);
1028         videobuf_queue_unlock(q);
1029 }
1030 EXPORT_SYMBOL_GPL(videobuf_read_stop);
1031
1032 void videobuf_stop(struct videobuf_queue *q)
1033 {
1034         videobuf_queue_lock(q);
1035
1036         if (q->streaming)
1037                 __videobuf_streamoff(q);
1038
1039         if (q->reading)
1040                 __videobuf_read_stop(q);
1041
1042         videobuf_queue_unlock(q);
1043 }
1044 EXPORT_SYMBOL_GPL(videobuf_stop);
1045
1046 ssize_t videobuf_read_stream(struct videobuf_queue *q,
1047                              char __user *data, size_t count, loff_t *ppos,
1048                              int vbihack, int nonblocking)
1049 {
1050         int rc, retval;
1051         unsigned long flags = 0;
1052
1053         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
1054
1055         dprintk(2, "%s\n", __func__);
1056         videobuf_queue_lock(q);
1057         retval = -EBUSY;
1058         if (q->streaming)
1059                 goto done;
1060         if (!q->reading) {
1061                 retval = __videobuf_read_start(q);
1062                 if (retval < 0)
1063                         goto done;
1064         }
1065
1066         retval = 0;
1067         while (count > 0) {
1068                 /* get / wait for data */
1069                 if (NULL == q->read_buf) {
1070                         q->read_buf = list_entry(q->stream.next,
1071                                                  struct videobuf_buffer,
1072                                                  stream);
1073                         list_del(&q->read_buf->stream);
1074                         q->read_off = 0;
1075                 }
1076                 rc = videobuf_waiton(q, q->read_buf, nonblocking, 1);
1077                 if (rc < 0) {
1078                         if (0 == retval)
1079                                 retval = rc;
1080                         break;
1081                 }
1082
1083                 if (q->read_buf->state == VIDEOBUF_DONE) {
1084                         rc = __videobuf_copy_stream(q, q->read_buf, data + retval, count,
1085                                         retval, vbihack, nonblocking);
1086                         if (rc < 0) {
1087                                 retval = rc;
1088                                 break;
1089                         }
1090                         retval      += rc;
1091                         count       -= rc;
1092                         q->read_off += rc;
1093                 } else {
1094                         /* some error */
1095                         q->read_off = q->read_buf->size;
1096                         if (0 == retval)
1097                                 retval = -EIO;
1098                 }
1099
1100                 /* requeue buffer when done with copying */
1101                 if (q->read_off == q->read_buf->size) {
1102                         list_add_tail(&q->read_buf->stream,
1103                                       &q->stream);
1104                         spin_lock_irqsave(q->irqlock, flags);
1105                         q->ops->buf_queue(q, q->read_buf);
1106                         spin_unlock_irqrestore(q->irqlock, flags);
1107                         q->read_buf = NULL;
1108                 }
1109                 if (retval < 0)
1110                         break;
1111         }
1112
1113 done:
1114         videobuf_queue_unlock(q);
1115         return retval;
1116 }
1117 EXPORT_SYMBOL_GPL(videobuf_read_stream);
1118
1119 __poll_t videobuf_poll_stream(struct file *file,
1120                               struct videobuf_queue *q,
1121                               poll_table *wait)
1122 {
1123         __poll_t req_events = poll_requested_events(wait);
1124         struct videobuf_buffer *buf = NULL;
1125         __poll_t rc = 0;
1126
1127         videobuf_queue_lock(q);
1128         if (q->streaming) {
1129                 if (!list_empty(&q->stream))
1130                         buf = list_entry(q->stream.next,
1131                                          struct videobuf_buffer, stream);
1132         } else if (req_events & (EPOLLIN | EPOLLRDNORM)) {
1133                 if (!q->reading)
1134                         __videobuf_read_start(q);
1135                 if (!q->reading) {
1136                         rc = EPOLLERR;
1137                 } else if (NULL == q->read_buf) {
1138                         q->read_buf = list_entry(q->stream.next,
1139                                                  struct videobuf_buffer,
1140                                                  stream);
1141                         list_del(&q->read_buf->stream);
1142                         q->read_off = 0;
1143                 }
1144                 buf = q->read_buf;
1145         }
1146         if (buf)
1147                 poll_wait(file, &buf->done, wait);
1148         else
1149                 rc = EPOLLERR;
1150
1151         if (0 == rc) {
1152                 if (buf->state == VIDEOBUF_DONE ||
1153                     buf->state == VIDEOBUF_ERROR) {
1154                         switch (q->type) {
1155                         case V4L2_BUF_TYPE_VIDEO_OUTPUT:
1156                         case V4L2_BUF_TYPE_VBI_OUTPUT:
1157                         case V4L2_BUF_TYPE_SLICED_VBI_OUTPUT:
1158                         case V4L2_BUF_TYPE_SDR_OUTPUT:
1159                                 rc = EPOLLOUT | EPOLLWRNORM;
1160                                 break;
1161                         default:
1162                                 rc = EPOLLIN | EPOLLRDNORM;
1163                                 break;
1164                         }
1165                 }
1166         }
1167         videobuf_queue_unlock(q);
1168         return rc;
1169 }
1170 EXPORT_SYMBOL_GPL(videobuf_poll_stream);
1171
1172 int videobuf_mmap_mapper(struct videobuf_queue *q, struct vm_area_struct *vma)
1173 {
1174         int rc = -EINVAL;
1175         int i;
1176
1177         MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
1178
1179         if (!(vma->vm_flags & VM_WRITE) || !(vma->vm_flags & VM_SHARED)) {
1180                 dprintk(1, "mmap appl bug: PROT_WRITE and MAP_SHARED are required\n");
1181                 return -EINVAL;
1182         }
1183
1184         videobuf_queue_lock(q);
1185         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
1186                 struct videobuf_buffer *buf = q->bufs[i];
1187
1188                 if (buf && buf->memory == V4L2_MEMORY_MMAP &&
1189                                 buf->boff == (vma->vm_pgoff << PAGE_SHIFT)) {
1190                         rc = CALL(q, mmap_mapper, q, buf, vma);
1191                         break;
1192                 }
1193         }
1194         videobuf_queue_unlock(q);
1195
1196         return rc;
1197 }
1198 EXPORT_SYMBOL_GPL(videobuf_mmap_mapper);