linux/drivers/media/usb/uvc/uvc_video.c
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   1/*
   2 *      uvc_video.c  --  USB Video Class driver - Video handling
   3 *
   4 *      Copyright (C) 2005-2010
   5 *          Laurent Pinchart (laurent.pinchart@ideasonboard.com)
   6 *
   7 *      This program is free software; you can redistribute it and/or modify
   8 *      it under the terms of the GNU General Public License as published by
   9 *      the Free Software Foundation; either version 2 of the License, or
  10 *      (at your option) any later version.
  11 *
  12 */
  13
  14#include <linux/kernel.h>
  15#include <linux/list.h>
  16#include <linux/module.h>
  17#include <linux/slab.h>
  18#include <linux/usb.h>
  19#include <linux/videodev2.h>
  20#include <linux/vmalloc.h>
  21#include <linux/wait.h>
  22#include <linux/atomic.h>
  23#include <asm/unaligned.h>
  24
  25#include <media/v4l2-common.h>
  26
  27#include "uvcvideo.h"
  28
  29/* ------------------------------------------------------------------------
  30 * UVC Controls
  31 */
  32
  33static int __uvc_query_ctrl(struct uvc_device *dev, __u8 query, __u8 unit,
  34                        __u8 intfnum, __u8 cs, void *data, __u16 size,
  35                        int timeout)
  36{
  37        __u8 type = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
  38        unsigned int pipe;
  39
  40        pipe = (query & 0x80) ? usb_rcvctrlpipe(dev->udev, 0)
  41                              : usb_sndctrlpipe(dev->udev, 0);
  42        type |= (query & 0x80) ? USB_DIR_IN : USB_DIR_OUT;
  43
  44        return usb_control_msg(dev->udev, pipe, query, type, cs << 8,
  45                        unit << 8 | intfnum, data, size, timeout);
  46}
  47
  48static const char *uvc_query_name(__u8 query)
  49{
  50        switch (query) {
  51        case UVC_SET_CUR:
  52                return "SET_CUR";
  53        case UVC_GET_CUR:
  54                return "GET_CUR";
  55        case UVC_GET_MIN:
  56                return "GET_MIN";
  57        case UVC_GET_MAX:
  58                return "GET_MAX";
  59        case UVC_GET_RES:
  60                return "GET_RES";
  61        case UVC_GET_LEN:
  62                return "GET_LEN";
  63        case UVC_GET_INFO:
  64                return "GET_INFO";
  65        case UVC_GET_DEF:
  66                return "GET_DEF";
  67        default:
  68                return "<invalid>";
  69        }
  70}
  71
  72int uvc_query_ctrl(struct uvc_device *dev, __u8 query, __u8 unit,
  73                        __u8 intfnum, __u8 cs, void *data, __u16 size)
  74{
  75        int ret;
  76
  77        ret = __uvc_query_ctrl(dev, query, unit, intfnum, cs, data, size,
  78                                UVC_CTRL_CONTROL_TIMEOUT);
  79        if (ret != size) {
  80                uvc_printk(KERN_ERR, "Failed to query (%s) UVC control %u on "
  81                        "unit %u: %d (exp. %u).\n", uvc_query_name(query), cs,
  82                        unit, ret, size);
  83                return -EIO;
  84        }
  85
  86        return 0;
  87}
  88
  89static void uvc_fixup_video_ctrl(struct uvc_streaming *stream,
  90        struct uvc_streaming_control *ctrl)
  91{
  92        struct uvc_format *format = NULL;
  93        struct uvc_frame *frame = NULL;
  94        unsigned int i;
  95
  96        for (i = 0; i < stream->nformats; ++i) {
  97                if (stream->format[i].index == ctrl->bFormatIndex) {
  98                        format = &stream->format[i];
  99                        break;
 100                }
 101        }
 102
 103        if (format == NULL)
 104                return;
 105
 106        for (i = 0; i < format->nframes; ++i) {
 107                if (format->frame[i].bFrameIndex == ctrl->bFrameIndex) {
 108                        frame = &format->frame[i];
 109                        break;
 110                }
 111        }
 112
 113        if (frame == NULL)
 114                return;
 115
 116        if (!(format->flags & UVC_FMT_FLAG_COMPRESSED) ||
 117             (ctrl->dwMaxVideoFrameSize == 0 &&
 118              stream->dev->uvc_version < 0x0110))
 119                ctrl->dwMaxVideoFrameSize =
 120                        frame->dwMaxVideoFrameBufferSize;
 121
 122        if (!(format->flags & UVC_FMT_FLAG_COMPRESSED) &&
 123            stream->dev->quirks & UVC_QUIRK_FIX_BANDWIDTH &&
 124            stream->intf->num_altsetting > 1) {
 125                u32 interval;
 126                u32 bandwidth;
 127
 128                interval = (ctrl->dwFrameInterval > 100000)
 129                         ? ctrl->dwFrameInterval
 130                         : frame->dwFrameInterval[0];
 131
 132                /* Compute a bandwidth estimation by multiplying the frame
 133                 * size by the number of video frames per second, divide the
 134                 * result by the number of USB frames (or micro-frames for
 135                 * high-speed devices) per second and add the UVC header size
 136                 * (assumed to be 12 bytes long).
 137                 */
 138                bandwidth = frame->wWidth * frame->wHeight / 8 * format->bpp;
 139                bandwidth *= 10000000 / interval + 1;
 140                bandwidth /= 1000;
 141                if (stream->dev->udev->speed == USB_SPEED_HIGH)
 142                        bandwidth /= 8;
 143                bandwidth += 12;
 144
 145                /* The bandwidth estimate is too low for many cameras. Don't use
 146                 * maximum packet sizes lower than 1024 bytes to try and work
 147                 * around the problem. According to measurements done on two
 148                 * different camera models, the value is high enough to get most
 149                 * resolutions working while not preventing two simultaneous
 150                 * VGA streams at 15 fps.
 151                 */
 152                bandwidth = max_t(u32, bandwidth, 1024);
 153
 154                ctrl->dwMaxPayloadTransferSize = bandwidth;
 155        }
 156}
 157
 158static int uvc_get_video_ctrl(struct uvc_streaming *stream,
 159        struct uvc_streaming_control *ctrl, int probe, __u8 query)
 160{
 161        __u8 *data;
 162        __u16 size;
 163        int ret;
 164
 165        size = stream->dev->uvc_version >= 0x0110 ? 34 : 26;
 166        if ((stream->dev->quirks & UVC_QUIRK_PROBE_DEF) &&
 167                        query == UVC_GET_DEF)
 168                return -EIO;
 169
 170        data = kmalloc(size, GFP_KERNEL);
 171        if (data == NULL)
 172                return -ENOMEM;
 173
 174        ret = __uvc_query_ctrl(stream->dev, query, 0, stream->intfnum,
 175                probe ? UVC_VS_PROBE_CONTROL : UVC_VS_COMMIT_CONTROL, data,
 176                size, uvc_timeout_param);
 177
 178        if ((query == UVC_GET_MIN || query == UVC_GET_MAX) && ret == 2) {
 179                /* Some cameras, mostly based on Bison Electronics chipsets,
 180                 * answer a GET_MIN or GET_MAX request with the wCompQuality
 181                 * field only.
 182                 */
 183                uvc_warn_once(stream->dev, UVC_WARN_MINMAX, "UVC non "
 184                        "compliance - GET_MIN/MAX(PROBE) incorrectly "
 185                        "supported. Enabling workaround.\n");
 186                memset(ctrl, 0, sizeof *ctrl);
 187                ctrl->wCompQuality = le16_to_cpup((__le16 *)data);
 188                ret = 0;
 189                goto out;
 190        } else if (query == UVC_GET_DEF && probe == 1 && ret != size) {
 191                /* Many cameras don't support the GET_DEF request on their
 192                 * video probe control. Warn once and return, the caller will
 193                 * fall back to GET_CUR.
 194                 */
 195                uvc_warn_once(stream->dev, UVC_WARN_PROBE_DEF, "UVC non "
 196                        "compliance - GET_DEF(PROBE) not supported. "
 197                        "Enabling workaround.\n");
 198                ret = -EIO;
 199                goto out;
 200        } else if (ret != size) {
 201                uvc_printk(KERN_ERR, "Failed to query (%u) UVC %s control : "
 202                        "%d (exp. %u).\n", query, probe ? "probe" : "commit",
 203                        ret, size);
 204                ret = -EIO;
 205                goto out;
 206        }
 207
 208        ctrl->bmHint = le16_to_cpup((__le16 *)&data[0]);
 209        ctrl->bFormatIndex = data[2];
 210        ctrl->bFrameIndex = data[3];
 211        ctrl->dwFrameInterval = le32_to_cpup((__le32 *)&data[4]);
 212        ctrl->wKeyFrameRate = le16_to_cpup((__le16 *)&data[8]);
 213        ctrl->wPFrameRate = le16_to_cpup((__le16 *)&data[10]);
 214        ctrl->wCompQuality = le16_to_cpup((__le16 *)&data[12]);
 215        ctrl->wCompWindowSize = le16_to_cpup((__le16 *)&data[14]);
 216        ctrl->wDelay = le16_to_cpup((__le16 *)&data[16]);
 217        ctrl->dwMaxVideoFrameSize = get_unaligned_le32(&data[18]);
 218        ctrl->dwMaxPayloadTransferSize = get_unaligned_le32(&data[22]);
 219
 220        if (size == 34) {
 221                ctrl->dwClockFrequency = get_unaligned_le32(&data[26]);
 222                ctrl->bmFramingInfo = data[30];
 223                ctrl->bPreferedVersion = data[31];
 224                ctrl->bMinVersion = data[32];
 225                ctrl->bMaxVersion = data[33];
 226        } else {
 227                ctrl->dwClockFrequency = stream->dev->clock_frequency;
 228                ctrl->bmFramingInfo = 0;
 229                ctrl->bPreferedVersion = 0;
 230                ctrl->bMinVersion = 0;
 231                ctrl->bMaxVersion = 0;
 232        }
 233
 234        /* Some broken devices return null or wrong dwMaxVideoFrameSize and
 235         * dwMaxPayloadTransferSize fields. Try to get the value from the
 236         * format and frame descriptors.
 237         */
 238        uvc_fixup_video_ctrl(stream, ctrl);
 239        ret = 0;
 240
 241out:
 242        kfree(data);
 243        return ret;
 244}
 245
 246static int uvc_set_video_ctrl(struct uvc_streaming *stream,
 247        struct uvc_streaming_control *ctrl, int probe)
 248{
 249        __u8 *data;
 250        __u16 size;
 251        int ret;
 252
 253        size = stream->dev->uvc_version >= 0x0110 ? 34 : 26;
 254        data = kzalloc(size, GFP_KERNEL);
 255        if (data == NULL)
 256                return -ENOMEM;
 257
 258        *(__le16 *)&data[0] = cpu_to_le16(ctrl->bmHint);
 259        data[2] = ctrl->bFormatIndex;
 260        data[3] = ctrl->bFrameIndex;
 261        *(__le32 *)&data[4] = cpu_to_le32(ctrl->dwFrameInterval);
 262        *(__le16 *)&data[8] = cpu_to_le16(ctrl->wKeyFrameRate);
 263        *(__le16 *)&data[10] = cpu_to_le16(ctrl->wPFrameRate);
 264        *(__le16 *)&data[12] = cpu_to_le16(ctrl->wCompQuality);
 265        *(__le16 *)&data[14] = cpu_to_le16(ctrl->wCompWindowSize);
 266        *(__le16 *)&data[16] = cpu_to_le16(ctrl->wDelay);
 267        put_unaligned_le32(ctrl->dwMaxVideoFrameSize, &data[18]);
 268        put_unaligned_le32(ctrl->dwMaxPayloadTransferSize, &data[22]);
 269
 270        if (size == 34) {
 271                put_unaligned_le32(ctrl->dwClockFrequency, &data[26]);
 272                data[30] = ctrl->bmFramingInfo;
 273                data[31] = ctrl->bPreferedVersion;
 274                data[32] = ctrl->bMinVersion;
 275                data[33] = ctrl->bMaxVersion;
 276        }
 277
 278        ret = __uvc_query_ctrl(stream->dev, UVC_SET_CUR, 0, stream->intfnum,
 279                probe ? UVC_VS_PROBE_CONTROL : UVC_VS_COMMIT_CONTROL, data,
 280                size, uvc_timeout_param);
 281        if (ret != size) {
 282                uvc_printk(KERN_ERR, "Failed to set UVC %s control : "
 283                        "%d (exp. %u).\n", probe ? "probe" : "commit",
 284                        ret, size);
 285                ret = -EIO;
 286        }
 287
 288        kfree(data);
 289        return ret;
 290}
 291
 292int uvc_probe_video(struct uvc_streaming *stream,
 293        struct uvc_streaming_control *probe)
 294{
 295        struct uvc_streaming_control probe_min, probe_max;
 296        __u16 bandwidth;
 297        unsigned int i;
 298        int ret;
 299
 300        /* Perform probing. The device should adjust the requested values
 301         * according to its capabilities. However, some devices, namely the
 302         * first generation UVC Logitech webcams, don't implement the Video
 303         * Probe control properly, and just return the needed bandwidth. For
 304         * that reason, if the needed bandwidth exceeds the maximum available
 305         * bandwidth, try to lower the quality.
 306         */
 307        ret = uvc_set_video_ctrl(stream, probe, 1);
 308        if (ret < 0)
 309                goto done;
 310
 311        /* Get the minimum and maximum values for compression settings. */
 312        if (!(stream->dev->quirks & UVC_QUIRK_PROBE_MINMAX)) {
 313                ret = uvc_get_video_ctrl(stream, &probe_min, 1, UVC_GET_MIN);
 314                if (ret < 0)
 315                        goto done;
 316                ret = uvc_get_video_ctrl(stream, &probe_max, 1, UVC_GET_MAX);
 317                if (ret < 0)
 318                        goto done;
 319
 320                probe->wCompQuality = probe_max.wCompQuality;
 321        }
 322
 323        for (i = 0; i < 2; ++i) {
 324                ret = uvc_set_video_ctrl(stream, probe, 1);
 325                if (ret < 0)
 326                        goto done;
 327                ret = uvc_get_video_ctrl(stream, probe, 1, UVC_GET_CUR);
 328                if (ret < 0)
 329                        goto done;
 330
 331                if (stream->intf->num_altsetting == 1)
 332                        break;
 333
 334                bandwidth = probe->dwMaxPayloadTransferSize;
 335                if (bandwidth <= stream->maxpsize)
 336                        break;
 337
 338                if (stream->dev->quirks & UVC_QUIRK_PROBE_MINMAX) {
 339                        ret = -ENOSPC;
 340                        goto done;
 341                }
 342
 343                /* TODO: negotiate compression parameters */
 344                probe->wKeyFrameRate = probe_min.wKeyFrameRate;
 345                probe->wPFrameRate = probe_min.wPFrameRate;
 346                probe->wCompQuality = probe_max.wCompQuality;
 347                probe->wCompWindowSize = probe_min.wCompWindowSize;
 348        }
 349
 350done:
 351        return ret;
 352}
 353
 354static int uvc_commit_video(struct uvc_streaming *stream,
 355                            struct uvc_streaming_control *probe)
 356{
 357        return uvc_set_video_ctrl(stream, probe, 0);
 358}
 359
 360/* -----------------------------------------------------------------------------
 361 * Clocks and timestamps
 362 */
 363
 364static inline void uvc_video_get_ts(struct timespec *ts)
 365{
 366        if (uvc_clock_param == CLOCK_MONOTONIC)
 367                ktime_get_ts(ts);
 368        else
 369                ktime_get_real_ts(ts);
 370}
 371
 372static void
 373uvc_video_clock_decode(struct uvc_streaming *stream, struct uvc_buffer *buf,
 374                       const __u8 *data, int len)
 375{
 376        struct uvc_clock_sample *sample;
 377        unsigned int header_size;
 378        bool has_pts = false;
 379        bool has_scr = false;
 380        unsigned long flags;
 381        struct timespec ts;
 382        u16 host_sof;
 383        u16 dev_sof;
 384
 385        switch (data[1] & (UVC_STREAM_PTS | UVC_STREAM_SCR)) {
 386        case UVC_STREAM_PTS | UVC_STREAM_SCR:
 387                header_size = 12;
 388                has_pts = true;
 389                has_scr = true;
 390                break;
 391        case UVC_STREAM_PTS:
 392                header_size = 6;
 393                has_pts = true;
 394                break;
 395        case UVC_STREAM_SCR:
 396                header_size = 8;
 397                has_scr = true;
 398                break;
 399        default:
 400                header_size = 2;
 401                break;
 402        }
 403
 404        /* Check for invalid headers. */
 405        if (len < header_size)
 406                return;
 407
 408        /* Extract the timestamps:
 409         *
 410         * - store the frame PTS in the buffer structure
 411         * - if the SCR field is present, retrieve the host SOF counter and
 412         *   kernel timestamps and store them with the SCR STC and SOF fields
 413         *   in the ring buffer
 414         */
 415        if (has_pts && buf != NULL)
 416                buf->pts = get_unaligned_le32(&data[2]);
 417
 418        if (!has_scr)
 419                return;
 420
 421        /* To limit the amount of data, drop SCRs with an SOF identical to the
 422         * previous one.
 423         */
 424        dev_sof = get_unaligned_le16(&data[header_size - 2]);
 425        if (dev_sof == stream->clock.last_sof)
 426                return;
 427
 428        stream->clock.last_sof = dev_sof;
 429
 430        host_sof = usb_get_current_frame_number(stream->dev->udev);
 431        uvc_video_get_ts(&ts);
 432
 433        /* The UVC specification allows device implementations that can't obtain
 434         * the USB frame number to keep their own frame counters as long as they
 435         * match the size and frequency of the frame number associated with USB
 436         * SOF tokens. The SOF values sent by such devices differ from the USB
 437         * SOF tokens by a fixed offset that needs to be estimated and accounted
 438         * for to make timestamp recovery as accurate as possible.
 439         *
 440         * The offset is estimated the first time a device SOF value is received
 441         * as the difference between the host and device SOF values. As the two
 442         * SOF values can differ slightly due to transmission delays, consider
 443         * that the offset is null if the difference is not higher than 10 ms
 444         * (negative differences can not happen and are thus considered as an
 445         * offset). The video commit control wDelay field should be used to
 446         * compute a dynamic threshold instead of using a fixed 10 ms value, but
 447         * devices don't report reliable wDelay values.
 448         *
 449         * See uvc_video_clock_host_sof() for an explanation regarding why only
 450         * the 8 LSBs of the delta are kept.
 451         */
 452        if (stream->clock.sof_offset == (u16)-1) {
 453                u16 delta_sof = (host_sof - dev_sof) & 255;
 454                if (delta_sof >= 10)
 455                        stream->clock.sof_offset = delta_sof;
 456                else
 457                        stream->clock.sof_offset = 0;
 458        }
 459
 460        dev_sof = (dev_sof + stream->clock.sof_offset) & 2047;
 461
 462        spin_lock_irqsave(&stream->clock.lock, flags);
 463
 464        sample = &stream->clock.samples[stream->clock.head];
 465        sample->dev_stc = get_unaligned_le32(&data[header_size - 6]);
 466        sample->dev_sof = dev_sof;
 467        sample->host_sof = host_sof;
 468        sample->host_ts = ts;
 469
 470        /* Update the sliding window head and count. */
 471        stream->clock.head = (stream->clock.head + 1) % stream->clock.size;
 472
 473        if (stream->clock.count < stream->clock.size)
 474                stream->clock.count++;
 475
 476        spin_unlock_irqrestore(&stream->clock.lock, flags);
 477}
 478
 479static void uvc_video_clock_reset(struct uvc_streaming *stream)
 480{
 481        struct uvc_clock *clock = &stream->clock;
 482
 483        clock->head = 0;
 484        clock->count = 0;
 485        clock->last_sof = -1;
 486        clock->sof_offset = -1;
 487}
 488
 489static int uvc_video_clock_init(struct uvc_streaming *stream)
 490{
 491        struct uvc_clock *clock = &stream->clock;
 492
 493        spin_lock_init(&clock->lock);
 494        clock->size = 32;
 495
 496        clock->samples = kmalloc(clock->size * sizeof(*clock->samples),
 497                                 GFP_KERNEL);
 498        if (clock->samples == NULL)
 499                return -ENOMEM;
 500
 501        uvc_video_clock_reset(stream);
 502
 503        return 0;
 504}
 505
 506static void uvc_video_clock_cleanup(struct uvc_streaming *stream)
 507{
 508        kfree(stream->clock.samples);
 509        stream->clock.samples = NULL;
 510}
 511
 512/*
 513 * uvc_video_clock_host_sof - Return the host SOF value for a clock sample
 514 *
 515 * Host SOF counters reported by usb_get_current_frame_number() usually don't
 516 * cover the whole 11-bits SOF range (0-2047) but are limited to the HCI frame
 517 * schedule window. They can be limited to 8, 9 or 10 bits depending on the host
 518 * controller and its configuration.
 519 *
 520 * We thus need to recover the SOF value corresponding to the host frame number.
 521 * As the device and host frame numbers are sampled in a short interval, the
 522 * difference between their values should be equal to a small delta plus an
 523 * integer multiple of 256 caused by the host frame number limited precision.
 524 *
 525 * To obtain the recovered host SOF value, compute the small delta by masking
 526 * the high bits of the host frame counter and device SOF difference and add it
 527 * to the device SOF value.
 528 */
 529static u16 uvc_video_clock_host_sof(const struct uvc_clock_sample *sample)
 530{
 531        /* The delta value can be negative. */
 532        s8 delta_sof;
 533
 534        delta_sof = (sample->host_sof - sample->dev_sof) & 255;
 535
 536        return (sample->dev_sof + delta_sof) & 2047;
 537}
 538
 539/*
 540 * uvc_video_clock_update - Update the buffer timestamp
 541 *
 542 * This function converts the buffer PTS timestamp to the host clock domain by
 543 * going through the USB SOF clock domain and stores the result in the V4L2
 544 * buffer timestamp field.
 545 *
 546 * The relationship between the device clock and the host clock isn't known.
 547 * However, the device and the host share the common USB SOF clock which can be
 548 * used to recover that relationship.
 549 *
 550 * The relationship between the device clock and the USB SOF clock is considered
 551 * to be linear over the clock samples sliding window and is given by
 552 *
 553 * SOF = m * PTS + p
 554 *
 555 * Several methods to compute the slope (m) and intercept (p) can be used. As
 556 * the clock drift should be small compared to the sliding window size, we
 557 * assume that the line that goes through the points at both ends of the window
 558 * is a good approximation. Naming those points P1 and P2, we get
 559 *
 560 * SOF = (SOF2 - SOF1) / (STC2 - STC1) * PTS
 561 *     + (SOF1 * STC2 - SOF2 * STC1) / (STC2 - STC1)
 562 *
 563 * or
 564 *
 565 * SOF = ((SOF2 - SOF1) * PTS + SOF1 * STC2 - SOF2 * STC1) / (STC2 - STC1)   (1)
 566 *
 567 * to avoid losing precision in the division. Similarly, the host timestamp is
 568 * computed with
 569 *
 570 * TS = ((TS2 - TS1) * PTS + TS1 * SOF2 - TS2 * SOF1) / (SOF2 - SOF1)        (2)
 571 *
 572 * SOF values are coded on 11 bits by USB. We extend their precision with 16
 573 * decimal bits, leading to a 11.16 coding.
 574 *
 575 * TODO: To avoid surprises with device clock values, PTS/STC timestamps should
 576 * be normalized using the nominal device clock frequency reported through the
 577 * UVC descriptors.
 578 *
 579 * Both the PTS/STC and SOF counters roll over, after a fixed but device
 580 * specific amount of time for PTS/STC and after 2048ms for SOF. As long as the
 581 * sliding window size is smaller than the rollover period, differences computed
 582 * on unsigned integers will produce the correct result. However, the p term in
 583 * the linear relations will be miscomputed.
 584 *
 585 * To fix the issue, we subtract a constant from the PTS and STC values to bring
 586 * PTS to half the 32 bit STC range. The sliding window STC values then fit into
 587 * the 32 bit range without any rollover.
 588 *
 589 * Similarly, we add 2048 to the device SOF values to make sure that the SOF
 590 * computed by (1) will never be smaller than 0. This offset is then compensated
 591 * by adding 2048 to the SOF values used in (2). However, this doesn't prevent
 592 * rollovers between (1) and (2): the SOF value computed by (1) can be slightly
 593 * lower than 4096, and the host SOF counters can have rolled over to 2048. This
 594 * case is handled by subtracting 2048 from the SOF value if it exceeds the host
 595 * SOF value at the end of the sliding window.
 596 *
 597 * Finally we subtract a constant from the host timestamps to bring the first
 598 * timestamp of the sliding window to 1s.
 599 */
 600void uvc_video_clock_update(struct uvc_streaming *stream,
 601                            struct v4l2_buffer *v4l2_buf,
 602                            struct uvc_buffer *buf)
 603{
 604        struct uvc_clock *clock = &stream->clock;
 605        struct uvc_clock_sample *first;
 606        struct uvc_clock_sample *last;
 607        unsigned long flags;
 608        struct timespec ts;
 609        u32 delta_stc;
 610        u32 y1, y2;
 611        u32 x1, x2;
 612        u32 mean;
 613        u32 sof;
 614        u32 div;
 615        u32 rem;
 616        u64 y;
 617
 618        spin_lock_irqsave(&clock->lock, flags);
 619
 620        if (clock->count < clock->size)
 621                goto done;
 622
 623        first = &clock->samples[clock->head];
 624        last = &clock->samples[(clock->head - 1) % clock->size];
 625
 626        /* First step, PTS to SOF conversion. */
 627        delta_stc = buf->pts - (1UL << 31);
 628        x1 = first->dev_stc - delta_stc;
 629        x2 = last->dev_stc - delta_stc;
 630        if (x1 == x2)
 631                goto done;
 632
 633        y1 = (first->dev_sof + 2048) << 16;
 634        y2 = (last->dev_sof + 2048) << 16;
 635        if (y2 < y1)
 636                y2 += 2048 << 16;
 637
 638        y = (u64)(y2 - y1) * (1ULL << 31) + (u64)y1 * (u64)x2
 639          - (u64)y2 * (u64)x1;
 640        y = div_u64(y, x2 - x1);
 641
 642        sof = y;
 643
 644        uvc_trace(UVC_TRACE_CLOCK, "%s: PTS %u y %llu.%06llu SOF %u.%06llu "
 645                  "(x1 %u x2 %u y1 %u y2 %u SOF offset %u)\n",
 646                  stream->dev->name, buf->pts,
 647                  y >> 16, div_u64((y & 0xffff) * 1000000, 65536),
 648                  sof >> 16, div_u64(((u64)sof & 0xffff) * 1000000LLU, 65536),
 649                  x1, x2, y1, y2, clock->sof_offset);
 650
 651        /* Second step, SOF to host clock conversion. */
 652        x1 = (uvc_video_clock_host_sof(first) + 2048) << 16;
 653        x2 = (uvc_video_clock_host_sof(last) + 2048) << 16;
 654        if (x2 < x1)
 655                x2 += 2048 << 16;
 656        if (x1 == x2)
 657                goto done;
 658
 659        ts = timespec_sub(last->host_ts, first->host_ts);
 660        y1 = NSEC_PER_SEC;
 661        y2 = (ts.tv_sec + 1) * NSEC_PER_SEC + ts.tv_nsec;
 662
 663        /* Interpolated and host SOF timestamps can wrap around at slightly
 664         * different times. Handle this by adding or removing 2048 to or from
 665         * the computed SOF value to keep it close to the SOF samples mean
 666         * value.
 667         */
 668        mean = (x1 + x2) / 2;
 669        if (mean - (1024 << 16) > sof)
 670                sof += 2048 << 16;
 671        else if (sof > mean + (1024 << 16))
 672                sof -= 2048 << 16;
 673
 674        y = (u64)(y2 - y1) * (u64)sof + (u64)y1 * (u64)x2
 675          - (u64)y2 * (u64)x1;
 676        y = div_u64(y, x2 - x1);
 677
 678        div = div_u64_rem(y, NSEC_PER_SEC, &rem);
 679        ts.tv_sec = first->host_ts.tv_sec - 1 + div;
 680        ts.tv_nsec = first->host_ts.tv_nsec + rem;
 681        if (ts.tv_nsec >= NSEC_PER_SEC) {
 682                ts.tv_sec++;
 683                ts.tv_nsec -= NSEC_PER_SEC;
 684        }
 685
 686        uvc_trace(UVC_TRACE_CLOCK, "%s: SOF %u.%06llu y %llu ts %lu.%06lu "
 687                  "buf ts %lu.%06lu (x1 %u/%u/%u x2 %u/%u/%u y1 %u y2 %u)\n",
 688                  stream->dev->name,
 689                  sof >> 16, div_u64(((u64)sof & 0xffff) * 1000000LLU, 65536),
 690                  y, ts.tv_sec, ts.tv_nsec / NSEC_PER_USEC,
 691                  v4l2_buf->timestamp.tv_sec,
 692                  (unsigned long)v4l2_buf->timestamp.tv_usec,
 693                  x1, first->host_sof, first->dev_sof,
 694                  x2, last->host_sof, last->dev_sof, y1, y2);
 695
 696        /* Update the V4L2 buffer. */
 697        v4l2_buf->timestamp.tv_sec = ts.tv_sec;
 698        v4l2_buf->timestamp.tv_usec = ts.tv_nsec / NSEC_PER_USEC;
 699
 700done:
 701        spin_unlock_irqrestore(&stream->clock.lock, flags);
 702}
 703
 704/* ------------------------------------------------------------------------
 705 * Stream statistics
 706 */
 707
 708static void uvc_video_stats_decode(struct uvc_streaming *stream,
 709                const __u8 *data, int len)
 710{
 711        unsigned int header_size;
 712        bool has_pts = false;
 713        bool has_scr = false;
 714        u16 uninitialized_var(scr_sof);
 715        u32 uninitialized_var(scr_stc);
 716        u32 uninitialized_var(pts);
 717
 718        if (stream->stats.stream.nb_frames == 0 &&
 719            stream->stats.frame.nb_packets == 0)
 720                ktime_get_ts(&stream->stats.stream.start_ts);
 721
 722        switch (data[1] & (UVC_STREAM_PTS | UVC_STREAM_SCR)) {
 723        case UVC_STREAM_PTS | UVC_STREAM_SCR:
 724                header_size = 12;
 725                has_pts = true;
 726                has_scr = true;
 727                break;
 728        case UVC_STREAM_PTS:
 729                header_size = 6;
 730                has_pts = true;
 731                break;
 732        case UVC_STREAM_SCR:
 733                header_size = 8;
 734                has_scr = true;
 735                break;
 736        default:
 737                header_size = 2;
 738                break;
 739        }
 740
 741        /* Check for invalid headers. */
 742        if (len < header_size || data[0] < header_size) {
 743                stream->stats.frame.nb_invalid++;
 744                return;
 745        }
 746
 747        /* Extract the timestamps. */
 748        if (has_pts)
 749                pts = get_unaligned_le32(&data[2]);
 750
 751        if (has_scr) {
 752                scr_stc = get_unaligned_le32(&data[header_size - 6]);
 753                scr_sof = get_unaligned_le16(&data[header_size - 2]);
 754        }
 755
 756        /* Is PTS constant through the whole frame ? */
 757        if (has_pts && stream->stats.frame.nb_pts) {
 758                if (stream->stats.frame.pts != pts) {
 759                        stream->stats.frame.nb_pts_diffs++;
 760                        stream->stats.frame.last_pts_diff =
 761                                stream->stats.frame.nb_packets;
 762                }
 763        }
 764
 765        if (has_pts) {
 766                stream->stats.frame.nb_pts++;
 767                stream->stats.frame.pts = pts;
 768        }
 769
 770        /* Do all frames have a PTS in their first non-empty packet, or before
 771         * their first empty packet ?
 772         */
 773        if (stream->stats.frame.size == 0) {
 774                if (len > header_size)
 775                        stream->stats.frame.has_initial_pts = has_pts;
 776                if (len == header_size && has_pts)
 777                        stream->stats.frame.has_early_pts = true;
 778        }
 779
 780        /* Do the SCR.STC and SCR.SOF fields vary through the frame ? */
 781        if (has_scr && stream->stats.frame.nb_scr) {
 782                if (stream->stats.frame.scr_stc != scr_stc)
 783                        stream->stats.frame.nb_scr_diffs++;
 784        }
 785
 786        if (has_scr) {
 787                /* Expand the SOF counter to 32 bits and store its value. */
 788                if (stream->stats.stream.nb_frames > 0 ||
 789                    stream->stats.frame.nb_scr > 0)
 790                        stream->stats.stream.scr_sof_count +=
 791                                (scr_sof - stream->stats.stream.scr_sof) % 2048;
 792                stream->stats.stream.scr_sof = scr_sof;
 793
 794                stream->stats.frame.nb_scr++;
 795                stream->stats.frame.scr_stc = scr_stc;
 796                stream->stats.frame.scr_sof = scr_sof;
 797
 798                if (scr_sof < stream->stats.stream.min_sof)
 799                        stream->stats.stream.min_sof = scr_sof;
 800                if (scr_sof > stream->stats.stream.max_sof)
 801                        stream->stats.stream.max_sof = scr_sof;
 802        }
 803
 804        /* Record the first non-empty packet number. */
 805        if (stream->stats.frame.size == 0 && len > header_size)
 806                stream->stats.frame.first_data = stream->stats.frame.nb_packets;
 807
 808        /* Update the frame size. */
 809        stream->stats.frame.size += len - header_size;
 810
 811        /* Update the packets counters. */
 812        stream->stats.frame.nb_packets++;
 813        if (len > header_size)
 814                stream->stats.frame.nb_empty++;
 815
 816        if (data[1] & UVC_STREAM_ERR)
 817                stream->stats.frame.nb_errors++;
 818}
 819
 820static void uvc_video_stats_update(struct uvc_streaming *stream)
 821{
 822        struct uvc_stats_frame *frame = &stream->stats.frame;
 823
 824        uvc_trace(UVC_TRACE_STATS, "frame %u stats: %u/%u/%u packets, "
 825                  "%u/%u/%u pts (%searly %sinitial), %u/%u scr, "
 826                  "last pts/stc/sof %u/%u/%u\n",
 827                  stream->sequence, frame->first_data,
 828                  frame->nb_packets - frame->nb_empty, frame->nb_packets,
 829                  frame->nb_pts_diffs, frame->last_pts_diff, frame->nb_pts,
 830                  frame->has_early_pts ? "" : "!",
 831                  frame->has_initial_pts ? "" : "!",
 832                  frame->nb_scr_diffs, frame->nb_scr,
 833                  frame->pts, frame->scr_stc, frame->scr_sof);
 834
 835        stream->stats.stream.nb_frames++;
 836        stream->stats.stream.nb_packets += stream->stats.frame.nb_packets;
 837        stream->stats.stream.nb_empty += stream->stats.frame.nb_empty;
 838        stream->stats.stream.nb_errors += stream->stats.frame.nb_errors;
 839        stream->stats.stream.nb_invalid += stream->stats.frame.nb_invalid;
 840
 841        if (frame->has_early_pts)
 842                stream->stats.stream.nb_pts_early++;
 843        if (frame->has_initial_pts)
 844                stream->stats.stream.nb_pts_initial++;
 845        if (frame->last_pts_diff <= frame->first_data)
 846                stream->stats.stream.nb_pts_constant++;
 847        if (frame->nb_scr >= frame->nb_packets - frame->nb_empty)
 848                stream->stats.stream.nb_scr_count_ok++;
 849        if (frame->nb_scr_diffs + 1 == frame->nb_scr)
 850                stream->stats.stream.nb_scr_diffs_ok++;
 851
 852        memset(&stream->stats.frame, 0, sizeof(stream->stats.frame));
 853}
 854
 855size_t uvc_video_stats_dump(struct uvc_streaming *stream, char *buf,
 856                            size_t size)
 857{
 858        unsigned int scr_sof_freq;
 859        unsigned int duration;
 860        struct timespec ts;
 861        size_t count = 0;
 862
 863        ts.tv_sec = stream->stats.stream.stop_ts.tv_sec
 864                  - stream->stats.stream.start_ts.tv_sec;
 865        ts.tv_nsec = stream->stats.stream.stop_ts.tv_nsec
 866                   - stream->stats.stream.start_ts.tv_nsec;
 867        if (ts.tv_nsec < 0) {
 868                ts.tv_sec--;
 869                ts.tv_nsec += 1000000000;
 870        }
 871
 872        /* Compute the SCR.SOF frequency estimate. At the nominal 1kHz SOF
 873         * frequency this will not overflow before more than 1h.
 874         */
 875        duration = ts.tv_sec * 1000 + ts.tv_nsec / 1000000;
 876        if (duration != 0)
 877                scr_sof_freq = stream->stats.stream.scr_sof_count * 1000
 878                             / duration;
 879        else
 880                scr_sof_freq = 0;
 881
 882        count += scnprintf(buf + count, size - count,
 883                           "frames:  %u\npackets: %u\nempty:   %u\n"
 884                           "errors:  %u\ninvalid: %u\n",
 885                           stream->stats.stream.nb_frames,
 886                           stream->stats.stream.nb_packets,
 887                           stream->stats.stream.nb_empty,
 888                           stream->stats.stream.nb_errors,
 889                           stream->stats.stream.nb_invalid);
 890        count += scnprintf(buf + count, size - count,
 891                           "pts: %u early, %u initial, %u ok\n",
 892                           stream->stats.stream.nb_pts_early,
 893                           stream->stats.stream.nb_pts_initial,
 894                           stream->stats.stream.nb_pts_constant);
 895        count += scnprintf(buf + count, size - count,
 896                           "scr: %u count ok, %u diff ok\n",
 897                           stream->stats.stream.nb_scr_count_ok,
 898                           stream->stats.stream.nb_scr_diffs_ok);
 899        count += scnprintf(buf + count, size - count,
 900                           "sof: %u <= sof <= %u, freq %u.%03u kHz\n",
 901                           stream->stats.stream.min_sof,
 902                           stream->stats.stream.max_sof,
 903                           scr_sof_freq / 1000, scr_sof_freq % 1000);
 904
 905        return count;
 906}
 907
 908static void uvc_video_stats_start(struct uvc_streaming *stream)
 909{
 910        memset(&stream->stats, 0, sizeof(stream->stats));
 911        stream->stats.stream.min_sof = 2048;
 912}
 913
 914static void uvc_video_stats_stop(struct uvc_streaming *stream)
 915{
 916        ktime_get_ts(&stream->stats.stream.stop_ts);
 917}
 918
 919/* ------------------------------------------------------------------------
 920 * Video codecs
 921 */
 922
 923/* Video payload decoding is handled by uvc_video_decode_start(),
 924 * uvc_video_decode_data() and uvc_video_decode_end().
 925 *
 926 * uvc_video_decode_start is called with URB data at the start of a bulk or
 927 * isochronous payload. It processes header data and returns the header size
 928 * in bytes if successful. If an error occurs, it returns a negative error
 929 * code. The following error codes have special meanings.
 930 *
 931 * - EAGAIN informs the caller that the current video buffer should be marked
 932 *   as done, and that the function should be called again with the same data
 933 *   and a new video buffer. This is used when end of frame conditions can be
 934 *   reliably detected at the beginning of the next frame only.
 935 *
 936 * If an error other than -EAGAIN is returned, the caller will drop the current
 937 * payload. No call to uvc_video_decode_data and uvc_video_decode_end will be
 938 * made until the next payload. -ENODATA can be used to drop the current
 939 * payload if no other error code is appropriate.
 940 *
 941 * uvc_video_decode_data is called for every URB with URB data. It copies the
 942 * data to the video buffer.
 943 *
 944 * uvc_video_decode_end is called with header data at the end of a bulk or
 945 * isochronous payload. It performs any additional header data processing and
 946 * returns 0 or a negative error code if an error occurred. As header data have
 947 * already been processed by uvc_video_decode_start, this functions isn't
 948 * required to perform sanity checks a second time.
 949 *
 950 * For isochronous transfers where a payload is always transferred in a single
 951 * URB, the three functions will be called in a row.
 952 *
 953 * To let the decoder process header data and update its internal state even
 954 * when no video buffer is available, uvc_video_decode_start must be prepared
 955 * to be called with a NULL buf parameter. uvc_video_decode_data and
 956 * uvc_video_decode_end will never be called with a NULL buffer.
 957 */
 958static int uvc_video_decode_start(struct uvc_streaming *stream,
 959                struct uvc_buffer *buf, const __u8 *data, int len)
 960{
 961        __u8 fid;
 962
 963        /* Sanity checks:
 964         * - packet must be at least 2 bytes long
 965         * - bHeaderLength value must be at least 2 bytes (see above)
 966         * - bHeaderLength value can't be larger than the packet size.
 967         */
 968        if (len < 2 || data[0] < 2 || data[0] > len) {
 969                stream->stats.frame.nb_invalid++;
 970                return -EINVAL;
 971        }
 972
 973        fid = data[1] & UVC_STREAM_FID;
 974
 975        /* Increase the sequence number regardless of any buffer states, so
 976         * that discontinuous sequence numbers always indicate lost frames.
 977         */
 978        if (stream->last_fid != fid) {
 979                stream->sequence++;
 980                if (stream->sequence)
 981                        uvc_video_stats_update(stream);
 982        }
 983
 984        uvc_video_clock_decode(stream, buf, data, len);
 985        uvc_video_stats_decode(stream, data, len);
 986
 987        /* Store the payload FID bit and return immediately when the buffer is
 988         * NULL.
 989         */
 990        if (buf == NULL) {
 991                stream->last_fid = fid;
 992                return -ENODATA;
 993        }
 994
 995        /* Mark the buffer as bad if the error bit is set. */
 996        if (data[1] & UVC_STREAM_ERR) {
 997                uvc_trace(UVC_TRACE_FRAME, "Marking buffer as bad (error bit "
 998                          "set).\n");
 999                buf->error = 1;
1000        }
1001
1002        /* Synchronize to the input stream by waiting for the FID bit to be
1003         * toggled when the the buffer state is not UVC_BUF_STATE_ACTIVE.
1004         * stream->last_fid is initialized to -1, so the first isochronous
1005         * frame will always be in sync.
1006         *
1007         * If the device doesn't toggle the FID bit, invert stream->last_fid
1008         * when the EOF bit is set to force synchronisation on the next packet.
1009         */
1010        if (buf->state != UVC_BUF_STATE_ACTIVE) {
1011                struct timespec ts;
1012
1013                if (fid == stream->last_fid) {
1014                        uvc_trace(UVC_TRACE_FRAME, "Dropping payload (out of "
1015                                "sync).\n");
1016                        if ((stream->dev->quirks & UVC_QUIRK_STREAM_NO_FID) &&
1017                            (data[1] & UVC_STREAM_EOF))
1018                                stream->last_fid ^= UVC_STREAM_FID;
1019                        return -ENODATA;
1020                }
1021
1022                uvc_video_get_ts(&ts);
1023
1024                buf->buf.v4l2_buf.field = V4L2_FIELD_NONE;
1025                buf->buf.v4l2_buf.sequence = stream->sequence;
1026                buf->buf.v4l2_buf.timestamp.tv_sec = ts.tv_sec;
1027                buf->buf.v4l2_buf.timestamp.tv_usec =
1028                        ts.tv_nsec / NSEC_PER_USEC;
1029
1030                /* TODO: Handle PTS and SCR. */
1031                buf->state = UVC_BUF_STATE_ACTIVE;
1032        }
1033
1034        /* Mark the buffer as done if we're at the beginning of a new frame.
1035         * End of frame detection is better implemented by checking the EOF
1036         * bit (FID bit toggling is delayed by one frame compared to the EOF
1037         * bit), but some devices don't set the bit at end of frame (and the
1038         * last payload can be lost anyway). We thus must check if the FID has
1039         * been toggled.
1040         *
1041         * stream->last_fid is initialized to -1, so the first isochronous
1042         * frame will never trigger an end of frame detection.
1043         *
1044         * Empty buffers (bytesused == 0) don't trigger end of frame detection
1045         * as it doesn't make sense to return an empty buffer. This also
1046         * avoids detecting end of frame conditions at FID toggling if the
1047         * previous payload had the EOF bit set.
1048         */
1049        if (fid != stream->last_fid && buf->bytesused != 0) {
1050                uvc_trace(UVC_TRACE_FRAME, "Frame complete (FID bit "
1051                                "toggled).\n");
1052                buf->state = UVC_BUF_STATE_READY;
1053                return -EAGAIN;
1054        }
1055
1056        stream->last_fid = fid;
1057
1058        return data[0];
1059}
1060
1061static void uvc_video_decode_data(struct uvc_streaming *stream,
1062                struct uvc_buffer *buf, const __u8 *data, int len)
1063{
1064        unsigned int maxlen, nbytes;
1065        void *mem;
1066
1067        if (len <= 0)
1068                return;
1069
1070        /* Copy the video data to the buffer. */
1071        maxlen = buf->length - buf->bytesused;
1072        mem = buf->mem + buf->bytesused;
1073        nbytes = min((unsigned int)len, maxlen);
1074        memcpy(mem, data, nbytes);
1075        buf->bytesused += nbytes;
1076
1077        /* Complete the current frame if the buffer size was exceeded. */
1078        if (len > maxlen) {
1079                uvc_trace(UVC_TRACE_FRAME, "Frame complete (overflow).\n");
1080                buf->state = UVC_BUF_STATE_READY;
1081        }
1082}
1083
1084static void uvc_video_decode_end(struct uvc_streaming *stream,
1085                struct uvc_buffer *buf, const __u8 *data, int len)
1086{
1087        /* Mark the buffer as done if the EOF marker is set. */
1088        if (data[1] & UVC_STREAM_EOF && buf->bytesused != 0) {
1089                uvc_trace(UVC_TRACE_FRAME, "Frame complete (EOF found).\n");
1090                if (data[0] == len)
1091                        uvc_trace(UVC_TRACE_FRAME, "EOF in empty payload.\n");
1092                buf->state = UVC_BUF_STATE_READY;
1093                if (stream->dev->quirks & UVC_QUIRK_STREAM_NO_FID)
1094                        stream->last_fid ^= UVC_STREAM_FID;
1095        }
1096}
1097
1098/* Video payload encoding is handled by uvc_video_encode_header() and
1099 * uvc_video_encode_data(). Only bulk transfers are currently supported.
1100 *
1101 * uvc_video_encode_header is called at the start of a payload. It adds header
1102 * data to the transfer buffer and returns the header size. As the only known
1103 * UVC output device transfers a whole frame in a single payload, the EOF bit
1104 * is always set in the header.
1105 *
1106 * uvc_video_encode_data is called for every URB and copies the data from the
1107 * video buffer to the transfer buffer.
1108 */
1109static int uvc_video_encode_header(struct uvc_streaming *stream,
1110                struct uvc_buffer *buf, __u8 *data, int len)
1111{
1112        data[0] = 2;    /* Header length */
1113        data[1] = UVC_STREAM_EOH | UVC_STREAM_EOF
1114                | (stream->last_fid & UVC_STREAM_FID);
1115        return 2;
1116}
1117
1118static int uvc_video_encode_data(struct uvc_streaming *stream,
1119                struct uvc_buffer *buf, __u8 *data, int len)
1120{
1121        struct uvc_video_queue *queue = &stream->queue;
1122        unsigned int nbytes;
1123        void *mem;
1124
1125        /* Copy video data to the URB buffer. */
1126        mem = buf->mem + queue->buf_used;
1127        nbytes = min((unsigned int)len, buf->bytesused - queue->buf_used);
1128        nbytes = min(stream->bulk.max_payload_size - stream->bulk.payload_size,
1129                        nbytes);
1130        memcpy(data, mem, nbytes);
1131
1132        queue->buf_used += nbytes;
1133
1134        return nbytes;
1135}
1136
1137/* ------------------------------------------------------------------------
1138 * URB handling
1139 */
1140
1141/*
1142 * Set error flag for incomplete buffer.
1143 */
1144static void uvc_video_validate_buffer(const struct uvc_streaming *stream,
1145                                      struct uvc_buffer *buf)
1146{
1147        if (stream->ctrl.dwMaxVideoFrameSize != buf->bytesused &&
1148            !(stream->cur_format->flags & UVC_FMT_FLAG_COMPRESSED))
1149                buf->error = 1;
1150}
1151
1152/*
1153 * Completion handler for video URBs.
1154 */
1155static void uvc_video_decode_isoc(struct urb *urb, struct uvc_streaming *stream,
1156        struct uvc_buffer *buf)
1157{
1158        u8 *mem;
1159        int ret, i;
1160
1161        for (i = 0; i < urb->number_of_packets; ++i) {
1162                if (urb->iso_frame_desc[i].status < 0) {
1163                        uvc_trace(UVC_TRACE_FRAME, "USB isochronous frame "
1164                                "lost (%d).\n", urb->iso_frame_desc[i].status);
1165                        /* Mark the buffer as faulty. */
1166                        if (buf != NULL)
1167                                buf->error = 1;
1168                        continue;
1169                }
1170
1171                /* Decode the payload header. */
1172                mem = urb->transfer_buffer + urb->iso_frame_desc[i].offset;
1173                do {
1174                        ret = uvc_video_decode_start(stream, buf, mem,
1175                                urb->iso_frame_desc[i].actual_length);
1176                        if (ret == -EAGAIN) {
1177                                uvc_video_validate_buffer(stream, buf);
1178                                buf = uvc_queue_next_buffer(&stream->queue,
1179                                                            buf);
1180                        }
1181                } while (ret == -EAGAIN);
1182
1183                if (ret < 0)
1184                        continue;
1185
1186                /* Decode the payload data. */
1187                uvc_video_decode_data(stream, buf, mem + ret,
1188                        urb->iso_frame_desc[i].actual_length - ret);
1189
1190                /* Process the header again. */
1191                uvc_video_decode_end(stream, buf, mem,
1192                        urb->iso_frame_desc[i].actual_length);
1193
1194                if (buf->state == UVC_BUF_STATE_READY) {
1195                        uvc_video_validate_buffer(stream, buf);
1196                        buf = uvc_queue_next_buffer(&stream->queue, buf);
1197                }
1198        }
1199}
1200
1201static void uvc_video_decode_bulk(struct urb *urb, struct uvc_streaming *stream,
1202        struct uvc_buffer *buf)
1203{
1204        u8 *mem;
1205        int len, ret;
1206
1207        /*
1208         * Ignore ZLPs if they're not part of a frame, otherwise process them
1209         * to trigger the end of payload detection.
1210         */
1211        if (urb->actual_length == 0 && stream->bulk.header_size == 0)
1212                return;
1213
1214        mem = urb->transfer_buffer;
1215        len = urb->actual_length;
1216        stream->bulk.payload_size += len;
1217
1218        /* If the URB is the first of its payload, decode and save the
1219         * header.
1220         */
1221        if (stream->bulk.header_size == 0 && !stream->bulk.skip_payload) {
1222                do {
1223                        ret = uvc_video_decode_start(stream, buf, mem, len);
1224                        if (ret == -EAGAIN)
1225                                buf = uvc_queue_next_buffer(&stream->queue,
1226                                                            buf);
1227                } while (ret == -EAGAIN);
1228
1229                /* If an error occurred skip the rest of the payload. */
1230                if (ret < 0 || buf == NULL) {
1231                        stream->bulk.skip_payload = 1;
1232                } else {
1233                        memcpy(stream->bulk.header, mem, ret);
1234                        stream->bulk.header_size = ret;
1235
1236                        mem += ret;
1237                        len -= ret;
1238                }
1239        }
1240
1241        /* The buffer queue might have been cancelled while a bulk transfer
1242         * was in progress, so we can reach here with buf equal to NULL. Make
1243         * sure buf is never dereferenced if NULL.
1244         */
1245
1246        /* Process video data. */
1247        if (!stream->bulk.skip_payload && buf != NULL)
1248                uvc_video_decode_data(stream, buf, mem, len);
1249
1250        /* Detect the payload end by a URB smaller than the maximum size (or
1251         * a payload size equal to the maximum) and process the header again.
1252         */
1253        if (urb->actual_length < urb->transfer_buffer_length ||
1254            stream->bulk.payload_size >= stream->bulk.max_payload_size) {
1255                if (!stream->bulk.skip_payload && buf != NULL) {
1256                        uvc_video_decode_end(stream, buf, stream->bulk.header,
1257                                stream->bulk.payload_size);
1258                        if (buf->state == UVC_BUF_STATE_READY)
1259                                buf = uvc_queue_next_buffer(&stream->queue,
1260                                                            buf);
1261                }
1262
1263                stream->bulk.header_size = 0;
1264                stream->bulk.skip_payload = 0;
1265                stream->bulk.payload_size = 0;
1266        }
1267}
1268
1269static void uvc_video_encode_bulk(struct urb *urb, struct uvc_streaming *stream,
1270        struct uvc_buffer *buf)
1271{
1272        u8 *mem = urb->transfer_buffer;
1273        int len = stream->urb_size, ret;
1274
1275        if (buf == NULL) {
1276                urb->transfer_buffer_length = 0;
1277                return;
1278        }
1279
1280        /* If the URB is the first of its payload, add the header. */
1281        if (stream->bulk.header_size == 0) {
1282                ret = uvc_video_encode_header(stream, buf, mem, len);
1283                stream->bulk.header_size = ret;
1284                stream->bulk.payload_size += ret;
1285                mem += ret;
1286                len -= ret;
1287        }
1288
1289        /* Process video data. */
1290        ret = uvc_video_encode_data(stream, buf, mem, len);
1291
1292        stream->bulk.payload_size += ret;
1293        len -= ret;
1294
1295        if (buf->bytesused == stream->queue.buf_used ||
1296            stream->bulk.payload_size == stream->bulk.max_payload_size) {
1297                if (buf->bytesused == stream->queue.buf_used) {
1298                        stream->queue.buf_used = 0;
1299                        buf->state = UVC_BUF_STATE_READY;
1300                        buf->buf.v4l2_buf.sequence = ++stream->sequence;
1301                        uvc_queue_next_buffer(&stream->queue, buf);
1302                        stream->last_fid ^= UVC_STREAM_FID;
1303                }
1304
1305                stream->bulk.header_size = 0;
1306                stream->bulk.payload_size = 0;
1307        }
1308
1309        urb->transfer_buffer_length = stream->urb_size - len;
1310}
1311
1312static void uvc_video_complete(struct urb *urb)
1313{
1314        struct uvc_streaming *stream = urb->context;
1315        struct uvc_video_queue *queue = &stream->queue;
1316        struct uvc_buffer *buf = NULL;
1317        unsigned long flags;
1318        int ret;
1319
1320        switch (urb->status) {
1321        case 0:
1322                break;
1323
1324        default:
1325                uvc_printk(KERN_WARNING, "Non-zero status (%d) in video "
1326                        "completion handler.\n", urb->status);
1327
1328        case -ENOENT:           /* usb_kill_urb() called. */
1329                if (stream->frozen)
1330                        return;
1331
1332        case -ECONNRESET:       /* usb_unlink_urb() called. */
1333        case -ESHUTDOWN:        /* The endpoint is being disabled. */
1334                uvc_queue_cancel(queue, urb->status == -ESHUTDOWN);
1335                return;
1336        }
1337
1338        spin_lock_irqsave(&queue->irqlock, flags);
1339        if (!list_empty(&queue->irqqueue))
1340                buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
1341                                       queue);
1342        spin_unlock_irqrestore(&queue->irqlock, flags);
1343
1344        stream->decode(urb, stream, buf);
1345
1346        if ((ret = usb_submit_urb(urb, GFP_ATOMIC)) < 0) {
1347                uvc_printk(KERN_ERR, "Failed to resubmit video URB (%d).\n",
1348                        ret);
1349        }
1350}
1351
1352/*
1353 * Free transfer buffers.
1354 */
1355static void uvc_free_urb_buffers(struct uvc_streaming *stream)
1356{
1357        unsigned int i;
1358
1359        for (i = 0; i < UVC_URBS; ++i) {
1360                if (stream->urb_buffer[i]) {
1361#ifndef CONFIG_DMA_NONCOHERENT
1362                        usb_free_coherent(stream->dev->udev, stream->urb_size,
1363                                stream->urb_buffer[i], stream->urb_dma[i]);
1364#else
1365                        kfree(stream->urb_buffer[i]);
1366#endif
1367                        stream->urb_buffer[i] = NULL;
1368                }
1369        }
1370
1371        stream->urb_size = 0;
1372}
1373
1374/*
1375 * Allocate transfer buffers. This function can be called with buffers
1376 * already allocated when resuming from suspend, in which case it will
1377 * return without touching the buffers.
1378 *
1379 * Limit the buffer size to UVC_MAX_PACKETS bulk/isochronous packets. If the
1380 * system is too low on memory try successively smaller numbers of packets
1381 * until allocation succeeds.
1382 *
1383 * Return the number of allocated packets on success or 0 when out of memory.
1384 */
1385static int uvc_alloc_urb_buffers(struct uvc_streaming *stream,
1386        unsigned int size, unsigned int psize, gfp_t gfp_flags)
1387{
1388        unsigned int npackets;
1389        unsigned int i;
1390
1391        /* Buffers are already allocated, bail out. */
1392        if (stream->urb_size)
1393                return stream->urb_size / psize;
1394
1395        /* Compute the number of packets. Bulk endpoints might transfer UVC
1396         * payloads across multiple URBs.
1397         */
1398        npackets = DIV_ROUND_UP(size, psize);
1399        if (npackets > UVC_MAX_PACKETS)
1400                npackets = UVC_MAX_PACKETS;
1401
1402        /* Retry allocations until one succeed. */
1403        for (; npackets > 1; npackets /= 2) {
1404                for (i = 0; i < UVC_URBS; ++i) {
1405                        stream->urb_size = psize * npackets;
1406#ifndef CONFIG_DMA_NONCOHERENT
1407                        stream->urb_buffer[i] = usb_alloc_coherent(
1408                                stream->dev->udev, stream->urb_size,
1409                                gfp_flags | __GFP_NOWARN, &stream->urb_dma[i]);
1410#else
1411                        stream->urb_buffer[i] =
1412                            kmalloc(stream->urb_size, gfp_flags | __GFP_NOWARN);
1413#endif
1414                        if (!stream->urb_buffer[i]) {
1415                                uvc_free_urb_buffers(stream);
1416                                break;
1417                        }
1418                }
1419
1420                if (i == UVC_URBS) {
1421                        uvc_trace(UVC_TRACE_VIDEO, "Allocated %u URB buffers "
1422                                "of %ux%u bytes each.\n", UVC_URBS, npackets,
1423                                psize);
1424                        return npackets;
1425                }
1426        }
1427
1428        uvc_trace(UVC_TRACE_VIDEO, "Failed to allocate URB buffers (%u bytes "
1429                "per packet).\n", psize);
1430        return 0;
1431}
1432
1433/*
1434 * Uninitialize isochronous/bulk URBs and free transfer buffers.
1435 */
1436static void uvc_uninit_video(struct uvc_streaming *stream, int free_buffers)
1437{
1438        struct urb *urb;
1439        unsigned int i;
1440
1441        uvc_video_stats_stop(stream);
1442
1443        for (i = 0; i < UVC_URBS; ++i) {
1444                urb = stream->urb[i];
1445                if (urb == NULL)
1446                        continue;
1447
1448                usb_kill_urb(urb);
1449                usb_free_urb(urb);
1450                stream->urb[i] = NULL;
1451        }
1452
1453        if (free_buffers)
1454                uvc_free_urb_buffers(stream);
1455}
1456
1457/*
1458 * Compute the maximum number of bytes per interval for an endpoint.
1459 */
1460static unsigned int uvc_endpoint_max_bpi(struct usb_device *dev,
1461                                         struct usb_host_endpoint *ep)
1462{
1463        u16 psize;
1464
1465        switch (dev->speed) {
1466        case USB_SPEED_SUPER:
1467                return le16_to_cpu(ep->ss_ep_comp.wBytesPerInterval);
1468        case USB_SPEED_HIGH:
1469                psize = usb_endpoint_maxp(&ep->desc);
1470                return (psize & 0x07ff) * (1 + ((psize >> 11) & 3));
1471        case USB_SPEED_WIRELESS:
1472                psize = usb_endpoint_maxp(&ep->desc);
1473                return psize;
1474        default:
1475                psize = usb_endpoint_maxp(&ep->desc);
1476                return psize & 0x07ff;
1477        }
1478}
1479
1480/*
1481 * Initialize isochronous URBs and allocate transfer buffers. The packet size
1482 * is given by the endpoint.
1483 */
1484static int uvc_init_video_isoc(struct uvc_streaming *stream,
1485        struct usb_host_endpoint *ep, gfp_t gfp_flags)
1486{
1487        struct urb *urb;
1488        unsigned int npackets, i, j;
1489        u16 psize;
1490        u32 size;
1491
1492        psize = uvc_endpoint_max_bpi(stream->dev->udev, ep);
1493        size = stream->ctrl.dwMaxVideoFrameSize;
1494
1495        npackets = uvc_alloc_urb_buffers(stream, size, psize, gfp_flags);
1496        if (npackets == 0)
1497                return -ENOMEM;
1498
1499        size = npackets * psize;
1500
1501        for (i = 0; i < UVC_URBS; ++i) {
1502                urb = usb_alloc_urb(npackets, gfp_flags);
1503                if (urb == NULL) {
1504                        uvc_uninit_video(stream, 1);
1505                        return -ENOMEM;
1506                }
1507
1508                urb->dev = stream->dev->udev;
1509                urb->context = stream;
1510                urb->pipe = usb_rcvisocpipe(stream->dev->udev,
1511                                ep->desc.bEndpointAddress);
1512#ifndef CONFIG_DMA_NONCOHERENT
1513                urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
1514                urb->transfer_dma = stream->urb_dma[i];
1515#else
1516                urb->transfer_flags = URB_ISO_ASAP;
1517#endif
1518                urb->interval = ep->desc.bInterval;
1519                urb->transfer_buffer = stream->urb_buffer[i];
1520                urb->complete = uvc_video_complete;
1521                urb->number_of_packets = npackets;
1522                urb->transfer_buffer_length = size;
1523
1524                for (j = 0; j < npackets; ++j) {
1525                        urb->iso_frame_desc[j].offset = j * psize;
1526                        urb->iso_frame_desc[j].length = psize;
1527                }
1528
1529                stream->urb[i] = urb;
1530        }
1531
1532        return 0;
1533}
1534
1535/*
1536 * Initialize bulk URBs and allocate transfer buffers. The packet size is
1537 * given by the endpoint.
1538 */
1539static int uvc_init_video_bulk(struct uvc_streaming *stream,
1540        struct usb_host_endpoint *ep, gfp_t gfp_flags)
1541{
1542        struct urb *urb;
1543        unsigned int npackets, pipe, i;
1544        u16 psize;
1545        u32 size;
1546
1547        psize = usb_endpoint_maxp(&ep->desc) & 0x7ff;
1548        size = stream->ctrl.dwMaxPayloadTransferSize;
1549        stream->bulk.max_payload_size = size;
1550
1551        npackets = uvc_alloc_urb_buffers(stream, size, psize, gfp_flags);
1552        if (npackets == 0)
1553                return -ENOMEM;
1554
1555        size = npackets * psize;
1556
1557        if (usb_endpoint_dir_in(&ep->desc))
1558                pipe = usb_rcvbulkpipe(stream->dev->udev,
1559                                       ep->desc.bEndpointAddress);
1560        else
1561                pipe = usb_sndbulkpipe(stream->dev->udev,
1562                                       ep->desc.bEndpointAddress);
1563
1564        if (stream->type == V4L2_BUF_TYPE_VIDEO_OUTPUT)
1565                size = 0;
1566
1567        for (i = 0; i < UVC_URBS; ++i) {
1568                urb = usb_alloc_urb(0, gfp_flags);
1569                if (urb == NULL) {
1570                        uvc_uninit_video(stream, 1);
1571                        return -ENOMEM;
1572                }
1573
1574                usb_fill_bulk_urb(urb, stream->dev->udev, pipe,
1575                        stream->urb_buffer[i], size, uvc_video_complete,
1576                        stream);
1577#ifndef CONFIG_DMA_NONCOHERENT
1578                urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1579                urb->transfer_dma = stream->urb_dma[i];
1580#endif
1581
1582                stream->urb[i] = urb;
1583        }
1584
1585        return 0;
1586}
1587
1588/*
1589 * Initialize isochronous/bulk URBs and allocate transfer buffers.
1590 */
1591static int uvc_init_video(struct uvc_streaming *stream, gfp_t gfp_flags)
1592{
1593        struct usb_interface *intf = stream->intf;
1594        struct usb_host_endpoint *ep;
1595        unsigned int i;
1596        int ret;
1597
1598        stream->sequence = -1;
1599        stream->last_fid = -1;
1600        stream->bulk.header_size = 0;
1601        stream->bulk.skip_payload = 0;
1602        stream->bulk.payload_size = 0;
1603
1604        uvc_video_stats_start(stream);
1605
1606        if (intf->num_altsetting > 1) {
1607                struct usb_host_endpoint *best_ep = NULL;
1608                unsigned int best_psize = UINT_MAX;
1609                unsigned int bandwidth;
1610                unsigned int uninitialized_var(altsetting);
1611                int intfnum = stream->intfnum;
1612
1613                /* Isochronous endpoint, select the alternate setting. */
1614                bandwidth = stream->ctrl.dwMaxPayloadTransferSize;
1615
1616                if (bandwidth == 0) {
1617                        uvc_trace(UVC_TRACE_VIDEO, "Device requested null "
1618                                "bandwidth, defaulting to lowest.\n");
1619                        bandwidth = 1;
1620                } else {
1621                        uvc_trace(UVC_TRACE_VIDEO, "Device requested %u "
1622                                "B/frame bandwidth.\n", bandwidth);
1623                }
1624
1625                for (i = 0; i < intf->num_altsetting; ++i) {
1626                        struct usb_host_interface *alts;
1627                        unsigned int psize;
1628
1629                        alts = &intf->altsetting[i];
1630                        ep = uvc_find_endpoint(alts,
1631                                stream->header.bEndpointAddress);
1632                        if (ep == NULL)
1633                                continue;
1634
1635                        /* Check if the bandwidth is high enough. */
1636                        psize = uvc_endpoint_max_bpi(stream->dev->udev, ep);
1637                        if (psize >= bandwidth && psize <= best_psize) {
1638                                altsetting = alts->desc.bAlternateSetting;
1639                                best_psize = psize;
1640                                best_ep = ep;
1641                        }
1642                }
1643
1644                if (best_ep == NULL) {
1645                        uvc_trace(UVC_TRACE_VIDEO, "No fast enough alt setting "
1646                                "for requested bandwidth.\n");
1647                        return -EIO;
1648                }
1649
1650                uvc_trace(UVC_TRACE_VIDEO, "Selecting alternate setting %u "
1651                        "(%u B/frame bandwidth).\n", altsetting, best_psize);
1652
1653                ret = usb_set_interface(stream->dev->udev, intfnum, altsetting);
1654                if (ret < 0)
1655                        return ret;
1656
1657                ret = uvc_init_video_isoc(stream, best_ep, gfp_flags);
1658        } else {
1659                /* Bulk endpoint, proceed to URB initialization. */
1660                ep = uvc_find_endpoint(&intf->altsetting[0],
1661                                stream->header.bEndpointAddress);
1662                if (ep == NULL)
1663                        return -EIO;
1664
1665                ret = uvc_init_video_bulk(stream, ep, gfp_flags);
1666        }
1667
1668        if (ret < 0)
1669                return ret;
1670
1671        /* Submit the URBs. */
1672        for (i = 0; i < UVC_URBS; ++i) {
1673                ret = usb_submit_urb(stream->urb[i], gfp_flags);
1674                if (ret < 0) {
1675                        uvc_printk(KERN_ERR, "Failed to submit URB %u "
1676                                        "(%d).\n", i, ret);
1677                        uvc_uninit_video(stream, 1);
1678                        return ret;
1679                }
1680        }
1681
1682        /* The Logitech C920 temporarily forgets that it should not be adjusting
1683         * Exposure Absolute during init so restore controls to stored values.
1684         */
1685        if (stream->dev->quirks & UVC_QUIRK_RESTORE_CTRLS_ON_INIT)
1686                uvc_ctrl_restore_values(stream->dev);
1687
1688        return 0;
1689}
1690
1691/* --------------------------------------------------------------------------
1692 * Suspend/resume
1693 */
1694
1695/*
1696 * Stop streaming without disabling the video queue.
1697 *
1698 * To let userspace applications resume without trouble, we must not touch the
1699 * video buffers in any way. We mark the device as frozen to make sure the URB
1700 * completion handler won't try to cancel the queue when we kill the URBs.
1701 */
1702int uvc_video_suspend(struct uvc_streaming *stream)
1703{
1704        if (!uvc_queue_streaming(&stream->queue))
1705                return 0;
1706
1707        stream->frozen = 1;
1708        uvc_uninit_video(stream, 0);
1709        usb_set_interface(stream->dev->udev, stream->intfnum, 0);
1710        return 0;
1711}
1712
1713/*
1714 * Reconfigure the video interface and restart streaming if it was enabled
1715 * before suspend.
1716 *
1717 * If an error occurs, disable the video queue. This will wake all pending
1718 * buffers, making sure userspace applications are notified of the problem
1719 * instead of waiting forever.
1720 */
1721int uvc_video_resume(struct uvc_streaming *stream, int reset)
1722{
1723        int ret;
1724
1725        /* If the bus has been reset on resume, set the alternate setting to 0.
1726         * This should be the default value, but some devices crash or otherwise
1727         * misbehave if they don't receive a SET_INTERFACE request before any
1728         * other video control request.
1729         */
1730        if (reset)
1731                usb_set_interface(stream->dev->udev, stream->intfnum, 0);
1732
1733        stream->frozen = 0;
1734
1735        uvc_video_clock_reset(stream);
1736
1737        ret = uvc_commit_video(stream, &stream->ctrl);
1738        if (ret < 0)
1739                return ret;
1740
1741        if (!uvc_queue_streaming(&stream->queue))
1742                return 0;
1743
1744        return uvc_init_video(stream, GFP_NOIO);
1745}
1746
1747/* ------------------------------------------------------------------------
1748 * Video device
1749 */
1750
1751/*
1752 * Initialize the UVC video device by switching to alternate setting 0 and
1753 * retrieve the default format.
1754 *
1755 * Some cameras (namely the Fuji Finepix) set the format and frame
1756 * indexes to zero. The UVC standard doesn't clearly make this a spec
1757 * violation, so try to silently fix the values if possible.
1758 *
1759 * This function is called before registering the device with V4L.
1760 */
1761int uvc_video_init(struct uvc_streaming *stream)
1762{
1763        struct uvc_streaming_control *probe = &stream->ctrl;
1764        struct uvc_format *format = NULL;
1765        struct uvc_frame *frame = NULL;
1766        unsigned int i;
1767        int ret;
1768
1769        if (stream->nformats == 0) {
1770                uvc_printk(KERN_INFO, "No supported video formats found.\n");
1771                return -EINVAL;
1772        }
1773
1774        atomic_set(&stream->active, 0);
1775
1776        /* Alternate setting 0 should be the default, yet the XBox Live Vision
1777         * Cam (and possibly other devices) crash or otherwise misbehave if
1778         * they don't receive a SET_INTERFACE request before any other video
1779         * control request.
1780         */
1781        usb_set_interface(stream->dev->udev, stream->intfnum, 0);
1782
1783        /* Set the streaming probe control with default streaming parameters
1784         * retrieved from the device. Webcams that don't suport GET_DEF
1785         * requests on the probe control will just keep their current streaming
1786         * parameters.
1787         */
1788        if (uvc_get_video_ctrl(stream, probe, 1, UVC_GET_DEF) == 0)
1789                uvc_set_video_ctrl(stream, probe, 1);
1790
1791        /* Initialize the streaming parameters with the probe control current
1792         * value. This makes sure SET_CUR requests on the streaming commit
1793         * control will always use values retrieved from a successful GET_CUR
1794         * request on the probe control, as required by the UVC specification.
1795         */
1796        ret = uvc_get_video_ctrl(stream, probe, 1, UVC_GET_CUR);
1797        if (ret < 0)
1798                return ret;
1799
1800        /* Check if the default format descriptor exists. Use the first
1801         * available format otherwise.
1802         */
1803        for (i = stream->nformats; i > 0; --i) {
1804                format = &stream->format[i-1];
1805                if (format->index == probe->bFormatIndex)
1806                        break;
1807        }
1808
1809        if (format->nframes == 0) {
1810                uvc_printk(KERN_INFO, "No frame descriptor found for the "
1811                        "default format.\n");
1812                return -EINVAL;
1813        }
1814
1815        /* Zero bFrameIndex might be correct. Stream-based formats (including
1816         * MPEG-2 TS and DV) do not support frames but have a dummy frame
1817         * descriptor with bFrameIndex set to zero. If the default frame
1818         * descriptor is not found, use the first available frame.
1819         */
1820        for (i = format->nframes; i > 0; --i) {
1821                frame = &format->frame[i-1];
1822                if (frame->bFrameIndex == probe->bFrameIndex)
1823                        break;
1824        }
1825
1826        probe->bFormatIndex = format->index;
1827        probe->bFrameIndex = frame->bFrameIndex;
1828
1829        stream->def_format = format;
1830        stream->cur_format = format;
1831        stream->cur_frame = frame;
1832
1833        /* Select the video decoding function */
1834        if (stream->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) {
1835                if (stream->dev->quirks & UVC_QUIRK_BUILTIN_ISIGHT)
1836                        stream->decode = uvc_video_decode_isight;
1837                else if (stream->intf->num_altsetting > 1)
1838                        stream->decode = uvc_video_decode_isoc;
1839                else
1840                        stream->decode = uvc_video_decode_bulk;
1841        } else {
1842                if (stream->intf->num_altsetting == 1)
1843                        stream->decode = uvc_video_encode_bulk;
1844                else {
1845                        uvc_printk(KERN_INFO, "Isochronous endpoints are not "
1846                                "supported for video output devices.\n");
1847                        return -EINVAL;
1848                }
1849        }
1850
1851        return 0;
1852}
1853
1854/*
1855 * Enable or disable the video stream.
1856 */
1857int uvc_video_enable(struct uvc_streaming *stream, int enable)
1858{
1859        int ret;
1860
1861        if (!enable) {
1862                uvc_uninit_video(stream, 1);
1863                if (stream->intf->num_altsetting > 1) {
1864                        usb_set_interface(stream->dev->udev,
1865                                          stream->intfnum, 0);
1866                } else {
1867                        /* UVC doesn't specify how to inform a bulk-based device
1868                         * when the video stream is stopped. Windows sends a
1869                         * CLEAR_FEATURE(HALT) request to the video streaming
1870                         * bulk endpoint, mimic the same behaviour.
1871                         */
1872                        unsigned int epnum = stream->header.bEndpointAddress
1873                                           & USB_ENDPOINT_NUMBER_MASK;
1874                        unsigned int dir = stream->header.bEndpointAddress
1875                                         & USB_ENDPOINT_DIR_MASK;
1876                        unsigned int pipe;
1877
1878                        pipe = usb_sndbulkpipe(stream->dev->udev, epnum) | dir;
1879                        usb_clear_halt(stream->dev->udev, pipe);
1880                }
1881
1882                uvc_video_clock_cleanup(stream);
1883                return 0;
1884        }
1885
1886        ret = uvc_video_clock_init(stream);
1887        if (ret < 0)
1888                return ret;
1889
1890        /* Commit the streaming parameters. */
1891        ret = uvc_commit_video(stream, &stream->ctrl);
1892        if (ret < 0)
1893                goto error_commit;
1894
1895        ret = uvc_init_video(stream, GFP_KERNEL);
1896        if (ret < 0)
1897                goto error_video;
1898
1899        return 0;
1900
1901error_video:
1902        usb_set_interface(stream->dev->udev, stream->intfnum, 0);
1903error_commit:
1904        uvc_video_clock_cleanup(stream);
1905
1906        return ret;
1907}
1908