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