linux/drivers/media/v4l2-core/videobuf-core.c
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   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
  37static int debug;
  38module_param(debug, int, 0644);
  39
  40MODULE_DESCRIPTION("helper module to manage video4linux buffers");
  41MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@infradead.org>");
  42MODULE_LICENSE("GPL");
  43
  44#define dprintk(level, fmt, arg...)                                     \
  45        do {                                                            \
  46                if (debug >= level)                                     \
  47                        printk(KERN_DEBUG "vbuf: " fmt, ## arg);        \
  48        } while (0)
  49
  50/* --------------------------------------------------------------------- */
  51
  52#define CALL(q, f, arg...)                                              \
  53        ((q->int_ops->f) ? q->int_ops->f(arg) : 0)
  54#define CALLPTR(q, f, arg...)                                           \
  55        ((q->int_ops->f) ? q->int_ops->f(arg) : NULL)
  56
  57struct videobuf_buffer *videobuf_alloc_vb(struct videobuf_queue *q)
  58{
  59        struct videobuf_buffer *vb;
  60
  61        BUG_ON(q->msize < sizeof(*vb));
  62
  63        if (!q->int_ops || !q->int_ops->alloc_vb) {
  64                printk(KERN_ERR "No specific ops defined!\n");
  65                BUG();
  66        }
  67
  68        vb = q->int_ops->alloc_vb(q->msize);
  69        if (NULL != vb) {
  70                init_waitqueue_head(&vb->done);
  71                vb->magic = MAGIC_BUFFER;
  72        }
  73
  74        return vb;
  75}
  76EXPORT_SYMBOL_GPL(videobuf_alloc_vb);
  77
  78static int is_state_active_or_queued(struct videobuf_queue *q, struct videobuf_buffer *vb)
  79{
  80        unsigned long flags;
  81        bool rc;
  82
  83        spin_lock_irqsave(q->irqlock, flags);
  84        rc = vb->state != VIDEOBUF_ACTIVE && vb->state != VIDEOBUF_QUEUED;
  85        spin_unlock_irqrestore(q->irqlock, flags);
  86        return rc;
  87};
  88
  89int videobuf_waiton(struct videobuf_queue *q, struct videobuf_buffer *vb,
  90                int non_blocking, int intr)
  91{
  92        bool is_ext_locked;
  93        int ret = 0;
  94
  95        MAGIC_CHECK(vb->magic, MAGIC_BUFFER);
  96
  97        if (non_blocking) {
  98                if (is_state_active_or_queued(q, vb))
  99                        return 0;
 100                return -EAGAIN;
 101        }
 102
 103        is_ext_locked = q->ext_lock && mutex_is_locked(q->ext_lock);
 104
 105        /* Release vdev lock to prevent this wait from blocking outside access to
 106           the device. */
 107        if (is_ext_locked)
 108                mutex_unlock(q->ext_lock);
 109        if (intr)
 110                ret = wait_event_interruptible(vb->done, is_state_active_or_queued(q, vb));
 111        else
 112                wait_event(vb->done, is_state_active_or_queued(q, vb));
 113        /* Relock */
 114        if (is_ext_locked)
 115                mutex_lock(q->ext_lock);
 116
 117        return ret;
 118}
 119EXPORT_SYMBOL_GPL(videobuf_waiton);
 120
 121int 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}
 129EXPORT_SYMBOL_GPL(videobuf_iolock);
 130
 131void *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}
 138EXPORT_SYMBOL_GPL(videobuf_queue_to_vaddr);
 139
 140/* --------------------------------------------------------------------- */
 141
 142
 143void 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}
 182EXPORT_SYMBOL_GPL(videobuf_queue_core_init);
 183
 184/* Locking: Only usage in bttv unsafe find way to remove */
 185int 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 avtive\n", i);
 216                        return 1;
 217                }
 218        }
 219        return 0;
 220}
 221EXPORT_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 */
 230static 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 */
 263void 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}
 293EXPORT_SYMBOL_GPL(videobuf_queue_cancel);
 294
 295/* --------------------------------------------------------------------- */
 296
 297/* Locking: Caller holds q->vb_lock */
 298enum 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}
 315EXPORT_SYMBOL_GPL(videobuf_next_field);
 316
 317/* Locking: Caller holds q->vb_lock */
 318static 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                /* fall through */
 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        b->timestamp = vb->ts;
 369        b->bytesused = vb->size;
 370        b->sequence  = vb->field_count >> 1;
 371}
 372
 373int 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}
 381EXPORT_SYMBOL_GPL(videobuf_mmap_free);
 382
 383/* Locking: Caller holds q->vb_lock */
 384int __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}
 426EXPORT_SYMBOL_GPL(__videobuf_mmap_setup);
 427
 428int 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}
 438EXPORT_SYMBOL_GPL(videobuf_mmap_setup);
 439
 440int 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}
 499EXPORT_SYMBOL_GPL(videobuf_reqbufs);
 500
 501int 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;
 522done:
 523        videobuf_queue_unlock(q);
 524        return ret;
 525}
 526EXPORT_SYMBOL_GPL(videobuf_querybuf);
 527
 528int 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                down_read(&current->mm->mmap_sem);
 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 "
 574                                   "but buffer addr is zero!\n");
 575                        goto done;
 576                }
 577                if (q->type == V4L2_BUF_TYPE_VIDEO_OUTPUT
 578                    || q->type == V4L2_BUF_TYPE_VBI_OUTPUT
 579                    || q->type == V4L2_BUF_TYPE_SLICED_VBI_OUTPUT
 580                    || q->type == V4L2_BUF_TYPE_SDR_OUTPUT) {
 581                        buf->size = b->bytesused;
 582                        buf->field = b->field;
 583                        buf->ts = b->timestamp;
 584                }
 585                break;
 586        case V4L2_MEMORY_USERPTR:
 587                if (b->length < buf->bsize) {
 588                        dprintk(1, "qbuf: buffer length is not enough\n");
 589                        goto done;
 590                }
 591                if (VIDEOBUF_NEEDS_INIT != buf->state &&
 592                    buf->baddr != b->m.userptr)
 593                        q->ops->buf_release(q, buf);
 594                buf->baddr = b->m.userptr;
 595                break;
 596        case V4L2_MEMORY_OVERLAY:
 597                buf->boff = b->m.offset;
 598                break;
 599        default:
 600                dprintk(1, "qbuf: wrong memory type\n");
 601                goto done;
 602        }
 603
 604        dprintk(1, "qbuf: requesting next field\n");
 605        field = videobuf_next_field(q);
 606        retval = q->ops->buf_prepare(q, buf, field);
 607        if (0 != retval) {
 608                dprintk(1, "qbuf: buffer_prepare returned %d\n", retval);
 609                goto done;
 610        }
 611
 612        list_add_tail(&buf->stream, &q->stream);
 613        if (q->streaming) {
 614                spin_lock_irqsave(q->irqlock, flags);
 615                q->ops->buf_queue(q, buf);
 616                spin_unlock_irqrestore(q->irqlock, flags);
 617        }
 618        dprintk(1, "qbuf: succeeded\n");
 619        retval = 0;
 620        wake_up_interruptible_sync(&q->wait);
 621
 622done:
 623        videobuf_queue_unlock(q);
 624
 625        if (b->memory == V4L2_MEMORY_MMAP)
 626                up_read(&current->mm->mmap_sem);
 627
 628        return retval;
 629}
 630EXPORT_SYMBOL_GPL(videobuf_qbuf);
 631
 632/* Locking: Caller holds q->vb_lock */
 633static int stream_next_buffer_check_queue(struct videobuf_queue *q, int noblock)
 634{
 635        int retval;
 636
 637checks:
 638        if (!q->streaming) {
 639                dprintk(1, "next_buffer: Not streaming\n");
 640                retval = -EINVAL;
 641                goto done;
 642        }
 643
 644        if (list_empty(&q->stream)) {
 645                if (noblock) {
 646                        retval = -EAGAIN;
 647                        dprintk(2, "next_buffer: no buffers to dequeue\n");
 648                        goto done;
 649                } else {
 650                        dprintk(2, "next_buffer: waiting on buffer\n");
 651
 652                        /* Drop lock to avoid deadlock with qbuf */
 653                        videobuf_queue_unlock(q);
 654
 655                        /* Checking list_empty and streaming is safe without
 656                         * locks because we goto checks to validate while
 657                         * holding locks before proceeding */
 658                        retval = wait_event_interruptible(q->wait,
 659                                !list_empty(&q->stream) || !q->streaming);
 660                        videobuf_queue_lock(q);
 661
 662                        if (retval)
 663                                goto done;
 664
 665                        goto checks;
 666                }
 667        }
 668
 669        retval = 0;
 670
 671done:
 672        return retval;
 673}
 674
 675/* Locking: Caller holds q->vb_lock */
 676static int stream_next_buffer(struct videobuf_queue *q,
 677                        struct videobuf_buffer **vb, int nonblocking)
 678{
 679        int retval;
 680        struct videobuf_buffer *buf = NULL;
 681
 682        retval = stream_next_buffer_check_queue(q, nonblocking);
 683        if (retval)
 684                goto done;
 685
 686        buf = list_entry(q->stream.next, struct videobuf_buffer, stream);
 687        retval = videobuf_waiton(q, buf, nonblocking, 1);
 688        if (retval < 0)
 689                goto done;
 690
 691        *vb = buf;
 692done:
 693        return retval;
 694}
 695
 696int videobuf_dqbuf(struct videobuf_queue *q,
 697                   struct v4l2_buffer *b, int nonblocking)
 698{
 699        struct videobuf_buffer *buf = NULL;
 700        int retval;
 701
 702        MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 703
 704        memset(b, 0, sizeof(*b));
 705        videobuf_queue_lock(q);
 706
 707        retval = stream_next_buffer(q, &buf, nonblocking);
 708        if (retval < 0) {
 709                dprintk(1, "dqbuf: next_buffer error: %i\n", retval);
 710                goto done;
 711        }
 712
 713        switch (buf->state) {
 714        case VIDEOBUF_ERROR:
 715                dprintk(1, "dqbuf: state is error\n");
 716                break;
 717        case VIDEOBUF_DONE:
 718                dprintk(1, "dqbuf: state is done\n");
 719                break;
 720        default:
 721                dprintk(1, "dqbuf: state invalid\n");
 722                retval = -EINVAL;
 723                goto done;
 724        }
 725        CALL(q, sync, q, buf);
 726        videobuf_status(q, b, buf, q->type);
 727        list_del(&buf->stream);
 728        buf->state = VIDEOBUF_IDLE;
 729        b->flags &= ~V4L2_BUF_FLAG_DONE;
 730done:
 731        videobuf_queue_unlock(q);
 732        return retval;
 733}
 734EXPORT_SYMBOL_GPL(videobuf_dqbuf);
 735
 736int videobuf_streamon(struct videobuf_queue *q)
 737{
 738        struct videobuf_buffer *buf;
 739        unsigned long flags = 0;
 740        int retval;
 741
 742        videobuf_queue_lock(q);
 743        retval = -EBUSY;
 744        if (q->reading)
 745                goto done;
 746        retval = 0;
 747        if (q->streaming)
 748                goto done;
 749        q->streaming = 1;
 750        spin_lock_irqsave(q->irqlock, flags);
 751        list_for_each_entry(buf, &q->stream, stream)
 752                if (buf->state == VIDEOBUF_PREPARED)
 753                        q->ops->buf_queue(q, buf);
 754        spin_unlock_irqrestore(q->irqlock, flags);
 755
 756        wake_up_interruptible_sync(&q->wait);
 757done:
 758        videobuf_queue_unlock(q);
 759        return retval;
 760}
 761EXPORT_SYMBOL_GPL(videobuf_streamon);
 762
 763/* Locking: Caller holds q->vb_lock */
 764static int __videobuf_streamoff(struct videobuf_queue *q)
 765{
 766        if (!q->streaming)
 767                return -EINVAL;
 768
 769        videobuf_queue_cancel(q);
 770
 771        return 0;
 772}
 773
 774int videobuf_streamoff(struct videobuf_queue *q)
 775{
 776        int retval;
 777
 778        videobuf_queue_lock(q);
 779        retval = __videobuf_streamoff(q);
 780        videobuf_queue_unlock(q);
 781
 782        return retval;
 783}
 784EXPORT_SYMBOL_GPL(videobuf_streamoff);
 785
 786/* Locking: Caller holds q->vb_lock */
 787static ssize_t videobuf_read_zerocopy(struct videobuf_queue *q,
 788                                      char __user *data,
 789                                      size_t count, loff_t *ppos)
 790{
 791        enum v4l2_field field;
 792        unsigned long flags = 0;
 793        int retval;
 794
 795        MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 796
 797        /* setup stuff */
 798        q->read_buf = videobuf_alloc_vb(q);
 799        if (NULL == q->read_buf)
 800                return -ENOMEM;
 801
 802        q->read_buf->memory = V4L2_MEMORY_USERPTR;
 803        q->read_buf->baddr  = (unsigned long)data;
 804        q->read_buf->bsize  = count;
 805
 806        field = videobuf_next_field(q);
 807        retval = q->ops->buf_prepare(q, q->read_buf, field);
 808        if (0 != retval)
 809                goto done;
 810
 811        /* start capture & wait */
 812        spin_lock_irqsave(q->irqlock, flags);
 813        q->ops->buf_queue(q, q->read_buf);
 814        spin_unlock_irqrestore(q->irqlock, flags);
 815        retval = videobuf_waiton(q, q->read_buf, 0, 0);
 816        if (0 == retval) {
 817                CALL(q, sync, q, q->read_buf);
 818                if (VIDEOBUF_ERROR == q->read_buf->state)
 819                        retval = -EIO;
 820                else
 821                        retval = q->read_buf->size;
 822        }
 823
 824done:
 825        /* cleanup */
 826        q->ops->buf_release(q, q->read_buf);
 827        kfree(q->read_buf);
 828        q->read_buf = NULL;
 829        return retval;
 830}
 831
 832static int __videobuf_copy_to_user(struct videobuf_queue *q,
 833                                   struct videobuf_buffer *buf,
 834                                   char __user *data, size_t count,
 835                                   int nonblocking)
 836{
 837        void *vaddr = CALLPTR(q, vaddr, buf);
 838
 839        /* copy to userspace */
 840        if (count > buf->size - q->read_off)
 841                count = buf->size - q->read_off;
 842
 843        if (copy_to_user(data, vaddr + q->read_off, count))
 844                return -EFAULT;
 845
 846        return count;
 847}
 848
 849static int __videobuf_copy_stream(struct videobuf_queue *q,
 850                                  struct videobuf_buffer *buf,
 851                                  char __user *data, size_t count, size_t pos,
 852                                  int vbihack, int nonblocking)
 853{
 854        unsigned int *fc = CALLPTR(q, vaddr, buf);
 855
 856        if (vbihack) {
 857                /* dirty, undocumented hack -- pass the frame counter
 858                        * within the last four bytes of each vbi data block.
 859                        * We need that one to maintain backward compatibility
 860                        * to all vbi decoding software out there ... */
 861                fc += (buf->size >> 2) - 1;
 862                *fc = buf->field_count >> 1;
 863                dprintk(1, "vbihack: %d\n", *fc);
 864        }
 865
 866        /* copy stuff using the common method */
 867        count = __videobuf_copy_to_user(q, buf, data, count, nonblocking);
 868
 869        if ((count == -EFAULT) && (pos == 0))
 870                return -EFAULT;
 871
 872        return count;
 873}
 874
 875ssize_t videobuf_read_one(struct videobuf_queue *q,
 876                          char __user *data, size_t count, loff_t *ppos,
 877                          int nonblocking)
 878{
 879        enum v4l2_field field;
 880        unsigned long flags = 0;
 881        unsigned size = 0, nbufs = 1;
 882        int retval;
 883
 884        MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
 885
 886        videobuf_queue_lock(q);
 887
 888        q->ops->buf_setup(q, &nbufs, &size);
 889
 890        if (NULL == q->read_buf  &&
 891            count >= size        &&
 892            !nonblocking) {
 893                retval = videobuf_read_zerocopy(q, data, count, ppos);
 894                if (retval >= 0  ||  retval == -EIO)
 895                        /* ok, all done */
 896                        goto done;
 897                /* fallback to kernel bounce buffer on failures */
 898        }
 899
 900        if (NULL == q->read_buf) {
 901                /* need to capture a new frame */
 902                retval = -ENOMEM;
 903                q->read_buf = videobuf_alloc_vb(q);
 904
 905                dprintk(1, "video alloc=0x%p\n", q->read_buf);
 906                if (NULL == q->read_buf)
 907                        goto done;
 908                q->read_buf->memory = V4L2_MEMORY_USERPTR;
 909                q->read_buf->bsize = count; /* preferred size */
 910                field = videobuf_next_field(q);
 911                retval = q->ops->buf_prepare(q, q->read_buf, field);
 912
 913                if (0 != retval) {
 914                        kfree(q->read_buf);
 915                        q->read_buf = NULL;
 916                        goto done;
 917                }
 918
 919                spin_lock_irqsave(q->irqlock, flags);
 920                q->ops->buf_queue(q, q->read_buf);
 921                spin_unlock_irqrestore(q->irqlock, flags);
 922
 923                q->read_off = 0;
 924        }
 925
 926        /* wait until capture is done */
 927        retval = videobuf_waiton(q, q->read_buf, nonblocking, 1);
 928        if (0 != retval)
 929                goto done;
 930
 931        CALL(q, sync, q, q->read_buf);
 932
 933        if (VIDEOBUF_ERROR == q->read_buf->state) {
 934                /* catch I/O errors */
 935                q->ops->buf_release(q, q->read_buf);
 936                kfree(q->read_buf);
 937                q->read_buf = NULL;
 938                retval = -EIO;
 939                goto done;
 940        }
 941
 942        /* Copy to userspace */
 943        retval = __videobuf_copy_to_user(q, q->read_buf, data, count, nonblocking);
 944        if (retval < 0)
 945                goto done;
 946
 947        q->read_off += retval;
 948        if (q->read_off == q->read_buf->size) {
 949                /* all data copied, cleanup */
 950                q->ops->buf_release(q, q->read_buf);
 951                kfree(q->read_buf);
 952                q->read_buf = NULL;
 953        }
 954
 955done:
 956        videobuf_queue_unlock(q);
 957        return retval;
 958}
 959EXPORT_SYMBOL_GPL(videobuf_read_one);
 960
 961/* Locking: Caller holds q->vb_lock */
 962static int __videobuf_read_start(struct videobuf_queue *q)
 963{
 964        enum v4l2_field field;
 965        unsigned long flags = 0;
 966        unsigned int count = 0, size = 0;
 967        int err, i;
 968
 969        q->ops->buf_setup(q, &count, &size);
 970        if (count < 2)
 971                count = 2;
 972        if (count > VIDEO_MAX_FRAME)
 973                count = VIDEO_MAX_FRAME;
 974        size = PAGE_ALIGN(size);
 975
 976        err = __videobuf_mmap_setup(q, count, size, V4L2_MEMORY_USERPTR);
 977        if (err < 0)
 978                return err;
 979
 980        count = err;
 981
 982        for (i = 0; i < count; i++) {
 983                field = videobuf_next_field(q);
 984                err = q->ops->buf_prepare(q, q->bufs[i], field);
 985                if (err)
 986                        return err;
 987                list_add_tail(&q->bufs[i]->stream, &q->stream);
 988        }
 989        spin_lock_irqsave(q->irqlock, flags);
 990        for (i = 0; i < count; i++)
 991                q->ops->buf_queue(q, q->bufs[i]);
 992        spin_unlock_irqrestore(q->irqlock, flags);
 993        q->reading = 1;
 994        return 0;
 995}
 996
 997static void __videobuf_read_stop(struct videobuf_queue *q)
 998{
 999        int i;
1000
1001        videobuf_queue_cancel(q);
1002        __videobuf_free(q);
1003        INIT_LIST_HEAD(&q->stream);
1004        for (i = 0; i < VIDEO_MAX_FRAME; i++) {
1005                if (NULL == q->bufs[i])
1006                        continue;
1007                kfree(q->bufs[i]);
1008                q->bufs[i] = NULL;
1009        }
1010        q->read_buf = NULL;
1011}
1012
1013int videobuf_read_start(struct videobuf_queue *q)
1014{
1015        int rc;
1016
1017        videobuf_queue_lock(q);
1018        rc = __videobuf_read_start(q);
1019        videobuf_queue_unlock(q);
1020
1021        return rc;
1022}
1023EXPORT_SYMBOL_GPL(videobuf_read_start);
1024
1025void videobuf_read_stop(struct videobuf_queue *q)
1026{
1027        videobuf_queue_lock(q);
1028        __videobuf_read_stop(q);
1029        videobuf_queue_unlock(q);
1030}
1031EXPORT_SYMBOL_GPL(videobuf_read_stop);
1032
1033void videobuf_stop(struct videobuf_queue *q)
1034{
1035        videobuf_queue_lock(q);
1036
1037        if (q->streaming)
1038                __videobuf_streamoff(q);
1039
1040        if (q->reading)
1041                __videobuf_read_stop(q);
1042
1043        videobuf_queue_unlock(q);
1044}
1045EXPORT_SYMBOL_GPL(videobuf_stop);
1046
1047ssize_t videobuf_read_stream(struct videobuf_queue *q,
1048                             char __user *data, size_t count, loff_t *ppos,
1049                             int vbihack, int nonblocking)
1050{
1051        int rc, retval;
1052        unsigned long flags = 0;
1053
1054        MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
1055
1056        dprintk(2, "%s\n", __func__);
1057        videobuf_queue_lock(q);
1058        retval = -EBUSY;
1059        if (q->streaming)
1060                goto done;
1061        if (!q->reading) {
1062                retval = __videobuf_read_start(q);
1063                if (retval < 0)
1064                        goto done;
1065        }
1066
1067        retval = 0;
1068        while (count > 0) {
1069                /* get / wait for data */
1070                if (NULL == q->read_buf) {
1071                        q->read_buf = list_entry(q->stream.next,
1072                                                 struct videobuf_buffer,
1073                                                 stream);
1074                        list_del(&q->read_buf->stream);
1075                        q->read_off = 0;
1076                }
1077                rc = videobuf_waiton(q, q->read_buf, nonblocking, 1);
1078                if (rc < 0) {
1079                        if (0 == retval)
1080                                retval = rc;
1081                        break;
1082                }
1083
1084                if (q->read_buf->state == VIDEOBUF_DONE) {
1085                        rc = __videobuf_copy_stream(q, q->read_buf, data + retval, count,
1086                                        retval, vbihack, nonblocking);
1087                        if (rc < 0) {
1088                                retval = rc;
1089                                break;
1090                        }
1091                        retval      += rc;
1092                        count       -= rc;
1093                        q->read_off += rc;
1094                } else {
1095                        /* some error */
1096                        q->read_off = q->read_buf->size;
1097                        if (0 == retval)
1098                                retval = -EIO;
1099                }
1100
1101                /* requeue buffer when done with copying */
1102                if (q->read_off == q->read_buf->size) {
1103                        list_add_tail(&q->read_buf->stream,
1104                                      &q->stream);
1105                        spin_lock_irqsave(q->irqlock, flags);
1106                        q->ops->buf_queue(q, q->read_buf);
1107                        spin_unlock_irqrestore(q->irqlock, flags);
1108                        q->read_buf = NULL;
1109                }
1110                if (retval < 0)
1111                        break;
1112        }
1113
1114done:
1115        videobuf_queue_unlock(q);
1116        return retval;
1117}
1118EXPORT_SYMBOL_GPL(videobuf_read_stream);
1119
1120unsigned int videobuf_poll_stream(struct file *file,
1121                                  struct videobuf_queue *q,
1122                                  poll_table *wait)
1123{
1124        unsigned long req_events = poll_requested_events(wait);
1125        struct videobuf_buffer *buf = NULL;
1126        unsigned int rc = 0;
1127
1128        videobuf_queue_lock(q);
1129        if (q->streaming) {
1130                if (!list_empty(&q->stream))
1131                        buf = list_entry(q->stream.next,
1132                                         struct videobuf_buffer, stream);
1133        } else if (req_events & (POLLIN | POLLRDNORM)) {
1134                if (!q->reading)
1135                        __videobuf_read_start(q);
1136                if (!q->reading) {
1137                        rc = POLLERR;
1138                } else if (NULL == q->read_buf) {
1139                        q->read_buf = list_entry(q->stream.next,
1140                                                 struct videobuf_buffer,
1141                                                 stream);
1142                        list_del(&q->read_buf->stream);
1143                        q->read_off = 0;
1144                }
1145                buf = q->read_buf;
1146        }
1147        if (!buf)
1148                rc = POLLERR;
1149
1150        if (0 == rc) {
1151                poll_wait(file, &buf->done, wait);
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 = POLLOUT | POLLWRNORM;
1160                                break;
1161                        default:
1162                                rc = POLLIN | POLLRDNORM;
1163                                break;
1164                        }
1165                }
1166        }
1167        videobuf_queue_unlock(q);
1168        return rc;
1169}
1170EXPORT_SYMBOL_GPL(videobuf_poll_stream);
1171
1172int 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}
1198EXPORT_SYMBOL_GPL(videobuf_mmap_mapper);
1199