drivers/media/usb/uvc/uvc_video.c

   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
  33 static 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
  48 static 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
  72 int 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
  89 static 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
 158 static 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
 241 out:
 242         kfree(data);
 243         return ret;
 244 }
 245
 246 static 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
 292 int 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
 350 done:
 351         return ret;
 352 }
 353
 354 static 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
 364 static 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
 372 static void
 373 uvc_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
 479 static 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
 489 static 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
 506 static 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  */
 529 static 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 loosing 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  */
 600 void 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, v4l2_buf->timestamp.tv_usec,
 692                   x1, first->host_sof, first->dev_sof,
 693                   x2, last->host_sof, last->dev_sof, y1, y2);
 694
 695         /* Update the V4L2 buffer. */
 696         v4l2_buf->timestamp.tv_sec = ts.tv_sec;
 697         v4l2_buf->timestamp.tv_usec = ts.tv_nsec / NSEC_PER_USEC;
 698
 699 done:
 700         spin_unlock_irqrestore(&stream->clock.lock, flags);
 701 }
 702
 703 /* ------------------------------------------------------------------------
 704  * Stream statistics
 705  */
 706
 707 static void uvc_video_stats_decode(struct uvc_streaming *stream,
 708                 const __u8 *data, int len)
 709 {
 710         unsigned int header_size;
 711         bool has_pts = false;
 712         bool has_scr = false;
 713         u16 uninitialized_var(scr_sof);
 714         u32 uninitialized_var(scr_stc);
 715         u32 uninitialized_var(pts);
 716
 717         if (stream->stats.stream.nb_frames == 0 &&
 718             stream->stats.frame.nb_packets == 0)
 719                 ktime_get_ts(&stream->stats.stream.start_ts);
 720
 721         switch (data[1] & (UVC_STREAM_PTS | UVC_STREAM_SCR)) {
 722         case UVC_STREAM_PTS | UVC_STREAM_SCR:
 723                 header_size = 12;
 724                 has_pts = true;
 725                 has_scr = true;
 726                 break;
 727         case UVC_STREAM_PTS:
 728                 header_size = 6;
 729                 has_pts = true;
 730                 break;
 731         case UVC_STREAM_SCR:
 732                 header_size = 8;
 733                 has_scr = true;
 734                 break;
 735         default:
 736                 header_size = 2;
 737                 break;
 738         }
 739
 740         /* Check for invalid headers. */
 741         if (len < header_size || data[0] < header_size) {
 742                 stream->stats.frame.nb_invalid++;
 743                 return;
 744         }
 745
 746         /* Extract the timestamps. */
 747         if (has_pts)
 748                 pts = get_unaligned_le32(&data[2]);
 749
 750         if (has_scr) {
 751                 scr_stc = get_unaligned_le32(&data[header_size - 6]);
 752                 scr_sof = get_unaligned_le16(&data[header_size - 2]);
 753         }
 754
 755         /* Is PTS constant through the whole frame ? */
 756         if (has_pts && stream->stats.frame.nb_pts) {
 757                 if (stream->stats.frame.pts != pts) {
 758                         stream->stats.frame.nb_pts_diffs++;
 759                         stream->stats.frame.last_pts_diff =
 760                                 stream->stats.frame.nb_packets;
 761                 }
 762         }
 763
 764         if (has_pts) {
 765                 stream->stats.frame.nb_pts++;
 766                 stream->stats.frame.pts = pts;
 767         }
 768
 769         /* Do all frames have a PTS in their first non-empty packet, or before
 770          * their first empty packet ?
 771          */
 772         if (stream->stats.frame.size == 0) {
 773                 if (len > header_size)
 774                         stream->stats.frame.has_initial_pts = has_pts;
 775                 if (len == header_size && has_pts)
 776                         stream->stats.frame.has_early_pts = true;
 777         }
 778
 779         /* Do the SCR.STC and SCR.SOF fields vary through the frame ? */
 780         if (has_scr && stream->stats.frame.nb_scr) {
 781                 if (stream->stats.frame.scr_stc != scr_stc)
 782                         stream->stats.frame.nb_scr_diffs++;
 783         }
 784
 785         if (has_scr) {
 786                 /* Expand the SOF counter to 32 bits and store its value. */
 787                 if (stream->stats.stream.nb_frames > 0 ||
 788                     stream->stats.frame.nb_scr > 0)
 789                         stream->stats.stream.scr_sof_count +=
 790                                 (scr_sof - stream->stats.stream.scr_sof) % 2048;
 791                 stream->stats.stream.scr_sof = scr_sof;
 792
 793                 stream->stats.frame.nb_scr++;
 794                 stream->stats.frame.scr_stc = scr_stc;
 795                 stream->stats.frame.scr_sof = scr_sof;
 796
 797                 if (scr_sof < stream->stats.stream.min_sof)
 798                         stream->stats.stream.min_sof = scr_sof;
 799                 if (scr_sof > stream->stats.stream.max_sof)
 800                         stream->stats.stream.max_sof = scr_sof;
 801         }
 802
 803         /* Record the first non-empty packet number. */
 804         if (stream->stats.frame.size == 0 && len > header_size)
 805                 stream->stats.frame.first_data = stream->stats.frame.nb_packets;
 806
 807         /* Update the frame size. */
 808         stream->stats.frame.size += len - header_size;
 809
 810         /* Update the packets counters. */
 811         stream->stats.frame.nb_packets++;
 812         if (len > header_size)
 813                 stream->stats.frame.nb_empty++;
 814
 815         if (data[1] & UVC_STREAM_ERR)
 816                 stream->stats.frame.nb_errors++;
 817 }
 818
 819 static void uvc_video_stats_update(struct uvc_streaming *stream)
 820 {
 821         struct uvc_stats_frame *frame = &stream->stats.frame;
 822
 823         uvc_trace(UVC_TRACE_STATS, "frame %u stats: %u/%u/%u packets, "
 824                   "%u/%u/%u pts (%searly %sinitial), %u/%u scr, "
 825                   "last pts/stc/sof %u/%u/%u\n",
 826                   stream->sequence, frame->first_data,
 827                   frame->nb_packets - frame->nb_empty, frame->nb_packets,
 828                   frame->nb_pts_diffs, frame->last_pts_diff, frame->nb_pts,
 829                   frame->has_early_pts ? "" : "!",
 830                   frame->has_initial_pts ? "" : "!",
 831                   frame->nb_scr_diffs, frame->nb_scr,
 832                   frame->pts, frame->scr_stc, frame->scr_sof);
 833
 834         stream->stats.stream.nb_frames++;
 835         stream->stats.stream.nb_packets += stream->stats.frame.nb_packets;
 836         stream->stats.stream.nb_empty += stream->stats.frame.nb_empty;
 837         stream->stats.stream.nb_errors += stream->stats.frame.nb_errors;
 838         stream->stats.stream.nb_invalid += stream->stats.frame.nb_invalid;
 839
 840         if (frame->has_early_pts)
 841                 stream->stats.stream.nb_pts_early++;
 842         if (frame->has_initial_pts)
 843                 stream->stats.stream.nb_pts_initial++;
 844         if (frame->last_pts_diff <= frame->first_data)
 845                 stream->stats.stream.nb_pts_constant++;
 846         if (frame->nb_scr >= frame->nb_packets - frame->nb_empty)
 847                 stream->stats.stream.nb_scr_count_ok++;
 848         if (frame->nb_scr_diffs + 1 == frame->nb_scr)
 849                 stream->stats.stream.nb_scr_diffs_ok++;
 850
 851         memset(&stream->stats.frame, 0, sizeof(stream->stats.frame));
 852 }
 853
 854 size_t uvc_video_stats_dump(struct uvc_streaming *stream, char *buf,
 855                             size_t size)
 856 {
 857         unsigned int scr_sof_freq;
 858         unsigned int duration;
 859         struct timespec ts;
 860         size_t count = 0;
 861
 862         ts.tv_sec = stream->stats.stream.stop_ts.tv_sec
 863                   - stream->stats.stream.start_ts.tv_sec;
 864         ts.tv_nsec = stream->stats.stream.stop_ts.tv_nsec
 865                    - stream->stats.stream.start_ts.tv_nsec;
 866         if (ts.tv_nsec < 0) {
 867                 ts.tv_sec--;
 868                 ts.tv_nsec += 1000000000;
 869         }
 870
 871         /* Compute the SCR.SOF frequency estimate. At the nominal 1kHz SOF
 872          * frequency this will not overflow before more than 1h.
 873          */
 874         duration = ts.tv_sec * 1000 + ts.tv_nsec / 1000000;
 875         if (duration != 0)
 876                 scr_sof_freq = stream->stats.stream.scr_sof_count * 1000
 877                              / duration;
 878         else
 879                 scr_sof_freq = 0;
 880
 881         count += scnprintf(buf + count, size - count,
 882                            "frames:  %u\npackets: %u\nempty:   %u\n"
 883                            "errors:  %u\ninvalid: %u\n",
 884                            stream->stats.stream.nb_frames,
 885                            stream->stats.stream.nb_packets,
 886                            stream->stats.stream.nb_empty,
 887                            stream->stats.stream.nb_errors,
 888                            stream->stats.stream.nb_invalid);
 889         count += scnprintf(buf + count, size - count,
 890                            "pts: %u early, %u initial, %u ok\n",
 891                            stream->stats.stream.nb_pts_early,
 892                            stream->stats.stream.nb_pts_initial,
 893                            stream->stats.stream.nb_pts_constant);
 894         count += scnprintf(buf + count, size - count,
 895                            "scr: %u count ok, %u diff ok\n",
 896                            stream->stats.stream.nb_scr_count_ok,
 897                            stream->stats.stream.nb_scr_diffs_ok);
 898         count += scnprintf(buf + count, size - count,
 899                            "sof: %u <= sof <= %u, freq %u.%03u kHz\n",
 900                            stream->stats.stream.min_sof,
 901                            stream->stats.stream.max_sof,
 902                            scr_sof_freq / 1000, scr_sof_freq % 1000);
 903
 904         return count;
 905 }
 906
 907 static void uvc_video_stats_start(struct uvc_streaming *stream)
 908 {
 909         memset(&stream->stats, 0, sizeof(stream->stats));
 910         stream->stats.stream.min_sof = 2048;
 911 }
 912
 913 static void uvc_video_stats_stop(struct uvc_streaming *stream)
 914 {
 915         ktime_get_ts(&stream->stats.stream.stop_ts);
 916 }
 917
 918 /* ------------------------------------------------------------------------
 919  * Video codecs
 920  */
 921
 922 /* Video payload decoding is handled by uvc_video_decode_start(),
 923  * uvc_video_decode_data() and uvc_video_decode_end().
 924  *
 925  * uvc_video_decode_start is called with URB data at the start of a bulk or
 926  * isochronous payload. It processes header data and returns the header size
 927  * in bytes if successful. If an error occurs, it returns a negative error
 928  * code. The following error codes have special meanings.
 929  *
 930  * - EAGAIN informs the caller that the current video buffer should be marked
 931  *   as done, and that the function should be called again with the same data
 932  *   and a new video buffer. This is used when end of frame conditions can be
 933  *   reliably detected at the beginning of the next frame only.
 934  *
 935  * If an error other than -EAGAIN is returned, the caller will drop the current
 936  * payload. No call to uvc_video_decode_data and uvc_video_decode_end will be
 937  * made until the next payload. -ENODATA can be used to drop the current
 938  * payload if no other error code is appropriate.
 939  *
 940  * uvc_video_decode_data is called for every URB with URB data. It copies the
 941  * data to the video buffer.
 942  *
 943  * uvc_video_decode_end is called with header data at the end of a bulk or
 944  * isochronous payload. It performs any additional header data processing and
 945  * returns 0 or a negative error code if an error occurred. As header data have
 946  * already been processed by uvc_video_decode_start, this functions isn't
 947  * required to perform sanity checks a second time.
 948  *
 949  * For isochronous transfers where a payload is always transferred in a single
 950  * URB, the three functions will be called in a row.
 951  *
 952  * To let the decoder process header data and update its internal state even
 953  * when no video buffer is available, uvc_video_decode_start must be prepared
 954  * to be called with a NULL buf parameter. uvc_video_decode_data and
 955  * uvc_video_decode_end will never be called with a NULL buffer.
 956  */
 957 static int uvc_video_decode_start(struct uvc_streaming *stream,
 958                 struct uvc_buffer *buf, const __u8 *data, int len)
 959 {
 960         __u8 fid;
 961
 962         /* Sanity checks:
 963          * - packet must be at least 2 bytes long
 964          * - bHeaderLength value must be at least 2 bytes (see above)
 965          * - bHeaderLength value can't be larger than the packet size.
 966          */
 967         if (len < 2 || data[0] < 2 || data[0] > len) {
 968                 stream->stats.frame.nb_invalid++;
 969                 return -EINVAL;
 970         }
 971
 972         fid = data[1] & UVC_STREAM_FID;
 973
 974         /* Increase the sequence number regardless of any buffer states, so
 975          * that discontinuous sequence numbers always indicate lost frames.
 976          */
 977         if (stream->last_fid != fid) {
 978                 stream->sequence++;
 979                 if (stream->sequence)
 980                         uvc_video_stats_update(stream);
 981         }
 982
 983         uvc_video_clock_decode(stream, buf, data, len);
 984         uvc_video_stats_decode(stream, data, len);
 985
 986         /* Store the payload FID bit and return immediately when the buffer is
 987          * NULL.
 988          */
 989         if (buf == NULL) {
 990                 stream->last_fid = fid;
 991                 return -ENODATA;
 992         }
 993
 994         /* Mark the buffer as bad if the error bit is set. */
 995         if (data[1] & UVC_STREAM_ERR) {
 996                 uvc_trace(UVC_TRACE_FRAME, "Marking buffer as bad (error bit "
 997                           "set).\n");
 998                 buf->error = 1;
 999         }
1000
1001         /* Synchronize to the input stream by waiting for the FID bit to be
1002          * toggled when the the buffer state is not UVC_BUF_STATE_ACTIVE.
1003          * stream->last_fid is initialized to -1, so the first isochronous
1004          * frame will always be in sync.
1005          *
1006          * If the device doesn't toggle the FID bit, invert stream->last_fid
1007          * when the EOF bit is set to force synchronisation on the next packet.
1008          */
1009         if (buf->state != UVC_BUF_STATE_ACTIVE) {
1010                 struct timespec ts;
1011
1012                 if (fid == stream->last_fid) {
1013                         uvc_trace(UVC_TRACE_FRAME, "Dropping payload (out of "
1014                                 "sync).\n");
1015                         if ((stream->dev->quirks & UVC_QUIRK_STREAM_NO_FID) &&
1016                             (data[1] & UVC_STREAM_EOF))
1017                                 stream->last_fid ^= UVC_STREAM_FID;
1018                         return -ENODATA;
1019                 }
1020
1021                 uvc_video_get_ts(&ts);
1022
1023                 buf->buf.v4l2_buf.sequence = stream->sequence;
1024                 buf->buf.v4l2_buf.timestamp.tv_sec = ts.tv_sec;
1025                 buf->buf.v4l2_buf.timestamp.tv_usec =
1026                         ts.tv_nsec / NSEC_PER_USEC;
1027
1028                 /* TODO: Handle PTS and SCR. */
1029                 buf->state = UVC_BUF_STATE_ACTIVE;
1030         }
1031
1032         /* Mark the buffer as done if we're at the beginning of a new frame.
1033          * End of frame detection is better implemented by checking the EOF
1034          * bit (FID bit toggling is delayed by one frame compared to the EOF
1035          * bit), but some devices don't set the bit at end of frame (and the
1036          * last payload can be lost anyway). We thus must check if the FID has
1037          * been toggled.
1038          *
1039          * stream->last_fid is initialized to -1, so the first isochronous
1040          * frame will never trigger an end of frame detection.
1041          *
1042          * Empty buffers (bytesused == 0) don't trigger end of frame detection
1043          * as it doesn't make sense to return an empty buffer. This also
1044          * avoids detecting end of frame conditions at FID toggling if the
1045          * previous payload had the EOF bit set.
1046          */
1047         if (fid != stream->last_fid && buf->bytesused != 0) {
1048                 uvc_trace(UVC_TRACE_FRAME, "Frame complete (FID bit "
1049                                 "toggled).\n");
1050                 buf->state = UVC_BUF_STATE_READY;
1051                 buf->error = 1;
1052                 return -EAGAIN;
1053         }
1054
1055         stream->last_fid = fid;
1056
1057         return data[0];
1058 }
1059
1060 static void uvc_video_decode_data(struct uvc_streaming *stream,
1061                 struct uvc_buffer *buf, const __u8 *data, int len)
1062 {
1063         unsigned int maxlen, nbytes;
1064         void *mem;
1065
1066         if (len <= 0)
1067                 return;
1068
1069         /* Copy the video data to the buffer. */
1070         maxlen = buf->length - buf->bytesused;
1071         mem = buf->mem + buf->bytesused;
1072         nbytes = min((unsigned int)len, maxlen);
1073         memcpy(mem, data, nbytes);
1074         buf->bytesused += nbytes;
1075
1076         /* Complete the current frame if the buffer size was exceeded. */
1077         if (len > maxlen) {
1078                 uvc_trace(UVC_TRACE_FRAME, "Frame complete (overflow).\n");
1079                 buf->state = UVC_BUF_STATE_READY;
1080                 buf->error = 1;
1081         }
1082 }
1083
1084 static 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  */
1109 static 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
1118 static 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  * Completion handler for video URBs.
1143  */
1144 static void uvc_video_decode_isoc(struct urb *urb, struct uvc_streaming *stream,
1145         struct uvc_buffer *buf)
1146 {
1147         u8 *mem;
1148         int ret, i;
1149
1150         for (i = 0; i < urb->number_of_packets; ++i) {
1151                 if (urb->iso_frame_desc[i].status < 0) {
1152                         uvc_trace(UVC_TRACE_FRAME, "USB isochronous frame "
1153                                 "lost (%d).\n", urb->iso_frame_desc[i].status);
1154                         /* Mark the buffer as faulty. */
1155                         if (buf != NULL)
1156                                 buf->error = 1;
1157                         continue;
1158                 }
1159
1160                 /* Decode the payload header. */
1161                 mem = urb->transfer_buffer + urb->iso_frame_desc[i].offset;
1162                 do {
1163                         ret = uvc_video_decode_start(stream, buf, mem,
1164                                 urb->iso_frame_desc[i].actual_length);
1165                         if (ret == -EAGAIN)
1166                                 buf = uvc_queue_next_buffer(&stream->queue,
1167                                                             buf);
1168                 } while (ret == -EAGAIN);
1169
1170                 if (ret < 0)
1171                         continue;
1172
1173                 /* Decode the payload data. */
1174                 uvc_video_decode_data(stream, buf, mem + ret,
1175                         urb->iso_frame_desc[i].actual_length - ret);
1176
1177                 /* Process the header again. */
1178                 uvc_video_decode_end(stream, buf, mem,
1179                         urb->iso_frame_desc[i].actual_length);
1180
1181                 if (buf->state == UVC_BUF_STATE_READY) {
1182                         if (buf->length != buf->bytesused &&
1183                             !(stream->cur_format->flags &
1184                               UVC_FMT_FLAG_COMPRESSED))
1185                                 buf->error = 1;
1186
1187                         buf = uvc_queue_next_buffer(&stream->queue, buf);
1188                 }
1189         }
1190 }
1191
1192 static void uvc_video_decode_bulk(struct urb *urb, struct uvc_streaming *stream,
1193         struct uvc_buffer *buf)
1194 {
1195         u8 *mem;
1196         int len, ret;
1197
1198         /*
1199          * Ignore ZLPs if they're not part of a frame, otherwise process them
1200          * to trigger the end of payload detection.
1201          */
1202         if (urb->actual_length == 0 && stream->bulk.header_size == 0)
1203                 return;
1204
1205         mem = urb->transfer_buffer;
1206         len = urb->actual_length;
1207         stream->bulk.payload_size += len;
1208
1209         /* If the URB is the first of its payload, decode and save the
1210          * header.
1211          */
1212         if (stream->bulk.header_size == 0 && !stream->bulk.skip_payload) {
1213                 do {
1214                         ret = uvc_video_decode_start(stream, buf, mem, len);
1215                         if (ret == -EAGAIN)
1216                                 buf = uvc_queue_next_buffer(&stream->queue,
1217                                                             buf);
1218                 } while (ret == -EAGAIN);
1219
1220                 /* If an error occurred skip the rest of the payload. */
1221                 if (ret < 0 || buf == NULL) {
1222                         stream->bulk.skip_payload = 1;
1223                 } else {
1224                         memcpy(stream->bulk.header, mem, ret);
1225                         stream->bulk.header_size = ret;
1226
1227                         mem += ret;
1228                         len -= ret;
1229                 }
1230         }
1231
1232         /* The buffer queue might have been cancelled while a bulk transfer
1233          * was in progress, so we can reach here with buf equal to NULL. Make
1234          * sure buf is never dereferenced if NULL.
1235          */
1236
1237         /* Process video data. */
1238         if (!stream->bulk.skip_payload && buf != NULL)
1239                 uvc_video_decode_data(stream, buf, mem, len);
1240
1241         /* Detect the payload end by a URB smaller than the maximum size (or
1242          * a payload size equal to the maximum) and process the header again.
1243          */
1244         if (urb->actual_length < urb->transfer_buffer_length ||
1245             stream->bulk.payload_size >= stream->bulk.max_payload_size) {
1246                 if (!stream->bulk.skip_payload && buf != NULL) {
1247                         uvc_video_decode_end(stream, buf, stream->bulk.header,
1248                                 stream->bulk.payload_size);
1249                         if (buf->state == UVC_BUF_STATE_READY)
1250                                 buf = uvc_queue_next_buffer(&stream->queue,
1251                                                             buf);
1252                 }
1253
1254                 stream->bulk.header_size = 0;
1255                 stream->bulk.skip_payload = 0;
1256                 stream->bulk.payload_size = 0;
1257         }
1258 }
1259
1260 static void uvc_video_encode_bulk(struct urb *urb, struct uvc_streaming *stream,
1261         struct uvc_buffer *buf)
1262 {
1263         u8 *mem = urb->transfer_buffer;
1264         int len = stream->urb_size, ret;
1265
1266         if (buf == NULL) {
1267                 urb->transfer_buffer_length = 0;
1268                 return;
1269         }
1270
1271         /* If the URB is the first of its payload, add the header. */
1272         if (stream->bulk.header_size == 0) {
1273                 ret = uvc_video_encode_header(stream, buf, mem, len);
1274                 stream->bulk.header_size = ret;
1275                 stream->bulk.payload_size += ret;
1276                 mem += ret;
1277                 len -= ret;
1278         }
1279
1280         /* Process video data. */
1281         ret = uvc_video_encode_data(stream, buf, mem, len);
1282
1283         stream->bulk.payload_size += ret;
1284         len -= ret;
1285
1286         if (buf->bytesused == stream->queue.buf_used ||
1287             stream->bulk.payload_size == stream->bulk.max_payload_size) {
1288                 if (buf->bytesused == stream->queue.buf_used) {
1289                         stream->queue.buf_used = 0;
1290                         buf->state = UVC_BUF_STATE_READY;
1291                         buf->buf.v4l2_buf.sequence = ++stream->sequence;
1292                         uvc_queue_next_buffer(&stream->queue, buf);
1293                         stream->last_fid ^= UVC_STREAM_FID;
1294                 }
1295
1296                 stream->bulk.header_size = 0;
1297                 stream->bulk.payload_size = 0;
1298         }
1299
1300         urb->transfer_buffer_length = stream->urb_size - len;
1301 }
1302 /* ddl@rock-chips.com : uvc_video_complete is run in_interrupt(), so uvc decode operation delay run in tasklet for
1303 *    usb host reenable interrupt soon
1304 */
1305 static void uvc_video_complete_fun (struct urb *urb)
1306 {
1307         struct uvc_streaming *stream = urb->context;
1308         struct uvc_video_queue *queue = &stream->queue;
1309         struct uvc_buffer *buf = NULL;
1310         unsigned long flags;
1311         int ret;
1312         int i;
1313         atomic_t *urb_state=NULL;
1314
1315         switch (urb->status) {
1316         case 0:
1317                 break;
1318
1319         default:
1320                 uvc_printk(KERN_WARNING, "Non-zero status (%d) in video "
1321                         "completion handler.\n", urb->status);
1322
1323         case -ENOENT:           /* usb_kill_urb() called. */
1324                 if (stream->frozen)
1325                         return;
1326
1327         case -ECONNRESET:       /* usb_unlink_urb() called. */
1328         case -ESHUTDOWN:        /* The endpoint is being disabled. */
1329                 uvc_queue_cancel(queue, urb->status == -ESHUTDOWN);
1330                 return;
1331         }
1332
1333         for (i = 0; i < UVC_URBS; ++i) {
1334                 if (stream->urb[i] == urb) {
1335                         urb_state = &stream->urb_state[i];
1336                         break;
1337                 }
1338         }
1339
1340         if (urb_state == NULL) {
1341                 printk("urb(%p) cann't be finded in stream->urb(%p, %p, %p, %p, %p)\n",
1342                         urb,stream->urb[0],stream->urb[1],stream->urb[2],stream->urb[3],stream->urb[4]);
1343                 /* BUG(); */
1344                 uvc_queue_cancel(queue, urb->status == -ESHUTDOWN);
1345                 return;
1346         }
1347
1348         if (atomic_read(urb_state)==UrbDeactive) {
1349                 printk(KERN_DEBUG "urb is deactive, this urb complete cancel!");
1350                 uvc_queue_cancel(queue, urb->status == -ESHUTDOWN);
1351                 return;
1352         }
1353
1354         spin_lock_irqsave(&queue->irqlock, flags);
1355         if (!list_empty(&queue->irqqueue))
1356                 buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
1357                                        queue);
1358         spin_unlock_irqrestore(&queue->irqlock, flags);
1359
1360         stream->decode(urb, stream, buf);
1361
1362         if ((ret = usb_submit_urb(urb, GFP_ATOMIC)) < 0) {
1363                 uvc_printk(KERN_ERR, "Failed to resubmit video URB (%d).\n",
1364                         ret);
1365                 uvc_queue_cancel(queue, urb->status == -ESHUTDOWN);
1366                 return;
1367         }
1368 }
1369 static void uvc_video_complete_tasklet(unsigned long data)
1370 {
1371         struct urb *urb = (struct urb*)data;
1372
1373         uvc_video_complete_fun(urb);
1374
1375         return;
1376 }
1377 static void uvc_video_complete(struct urb *urb)
1378 {
1379         int i;
1380         struct uvc_streaming *stream = urb->context;
1381         struct tasklet_struct *tasklet = NULL;
1382         atomic_t *urb_state;
1383
1384         for (i = 0; i < UVC_URBS; ++i) {
1385                 if (stream->urb[i] == urb) {
1386                         tasklet = stream->tasklet[i];
1387                         urb_state = &stream->urb_state[i];
1388                         break;
1389                 }
1390         }
1391
1392         if ((tasklet != NULL)&&(atomic_read(urb_state)==UrbActive)) {
1393                 tasklet_hi_schedule(tasklet);
1394         } else {
1395                 uvc_video_complete_fun(urb);
1396         }
1397 }
1398
1399 /*
1400  * Free transfer buffers.
1401  */
1402 static void uvc_free_urb_buffers(struct uvc_streaming *stream)
1403 {
1404         unsigned int i;
1405
1406         for (i = 0; i < UVC_URBS; ++i) {
1407                 if (stream->urb_buffer[i]) {
1408 #ifndef CONFIG_DMA_NONCOHERENT
1409                         usb_free_coherent(stream->dev->udev, stream->urb_size,
1410                                 stream->urb_buffer[i], stream->urb_dma[i]);
1411 #else
1412                         kfree(stream->urb_buffer[i]);
1413 #endif
1414                         stream->urb_buffer[i] = NULL;
1415                 }
1416         }
1417
1418         stream->urb_size = 0;
1419 }
1420
1421 /*
1422  * Allocate transfer buffers. This function can be called with buffers
1423  * already allocated when resuming from suspend, in which case it will
1424  * return without touching the buffers.
1425  *
1426  * Limit the buffer size to UVC_MAX_PACKETS bulk/isochronous packets. If the
1427  * system is too low on memory try successively smaller numbers of packets
1428  * until allocation succeeds.
1429  *
1430  * Return the number of allocated packets on success or 0 when out of memory.
1431  */
1432 static int uvc_alloc_urb_buffers(struct uvc_streaming *stream,
1433         unsigned int size, unsigned int psize, gfp_t gfp_flags)
1434 {
1435         unsigned int npackets;
1436         unsigned int i;
1437
1438         /* Buffers are already allocated, bail out. */
1439         if (stream->urb_size)
1440                 return stream->urb_size / psize;
1441
1442         /* Compute the number of packets. Bulk endpoints might transfer UVC
1443          * payloads across multiple URBs.
1444          */
1445         npackets = DIV_ROUND_UP(size, psize);
1446         if (npackets > UVC_MAX_PACKETS)
1447                 npackets = UVC_MAX_PACKETS;
1448
1449         /* Retry allocations until one succeed. */
1450         for (; npackets > 1; npackets /= 2) {
1451                 for (i = 0; i < UVC_URBS; ++i) {
1452                         stream->urb_size = psize * npackets;
1453 #ifndef CONFIG_DMA_NONCOHERENT
1454                         stream->urb_buffer[i] = usb_alloc_coherent(
1455                                 stream->dev->udev, stream->urb_size,
1456                                 gfp_flags | __GFP_NOWARN, &stream->urb_dma[i]);
1457 #else
1458                         stream->urb_buffer[i] =
1459                             kmalloc(stream->urb_size, gfp_flags | __GFP_NOWARN);
1460 #endif
1461                         if (!stream->urb_buffer[i]) {
1462                                 uvc_free_urb_buffers(stream);
1463                                 break;
1464                         }
1465                 }
1466
1467                 if (i == UVC_URBS) {
1468                         uvc_trace(UVC_TRACE_VIDEO, "Allocated %u URB buffers "
1469                                 "of %ux%u bytes each.\n", UVC_URBS, npackets,
1470                                 psize);
1471                         return npackets;
1472                 }
1473         }
1474
1475         uvc_trace(UVC_TRACE_VIDEO, "Failed to allocate URB buffers (%u bytes "
1476                 "per packet).\n", psize);
1477         return 0;
1478 }
1479
1480 /*
1481  * Uninitialize isochronous/bulk URBs and free transfer buffers.
1482  */
1483 static void uvc_uninit_video(struct uvc_streaming *stream, int free_buffers)
1484 {
1485         struct urb *urb;
1486         unsigned int i;
1487
1488         uvc_video_stats_stop(stream);
1489
1490         for (i = 0; i < UVC_URBS; ++i) {
1491                 urb = stream->urb[i];
1492                 if (urb == NULL)
1493                         continue;
1494                 else
1495                         atomic_set(&stream->urb_state[i],UrbDeactive);
1496
1497                 if (stream->tasklet[i]) {
1498                         tasklet_kill(stream->tasklet[i]);
1499                         kfree(stream->tasklet[i]);
1500                         stream->tasklet[i] = NULL;
1501                 }
1502
1503                 usb_kill_urb(urb);
1504                 usb_free_urb(urb);
1505                 stream->urb[i] = NULL;
1506         }
1507
1508         if (free_buffers)
1509                 uvc_free_urb_buffers(stream);
1510 }
1511
1512 /*
1513  * Compute the maximum number of bytes per interval for an endpoint.
1514  */
1515 static unsigned int uvc_endpoint_max_bpi(struct usb_device *dev,
1516                                          struct usb_host_endpoint *ep)
1517 {
1518         u16 psize;
1519
1520         switch (dev->speed) {
1521         case USB_SPEED_SUPER:
1522                 return ep->ss_ep_comp.wBytesPerInterval;
1523         case USB_SPEED_HIGH:
1524                 psize = usb_endpoint_maxp(&ep->desc);
1525                 return (psize & 0x07ff) * (1 + ((psize >> 11) & 3));
1526         default:
1527                 psize = usb_endpoint_maxp(&ep->desc);
1528                 return psize & 0x07ff;
1529         }
1530 }
1531
1532 /*
1533  * Initialize isochronous URBs and allocate transfer buffers. The packet size
1534  * is given by the endpoint.
1535  */
1536 static int uvc_init_video_isoc(struct uvc_streaming *stream,
1537         struct usb_host_endpoint *ep, gfp_t gfp_flags)
1538 {
1539         struct urb *urb;
1540         unsigned int npackets, i, j;
1541         u16 psize;
1542         u32 size;
1543
1544         psize = uvc_endpoint_max_bpi(stream->dev->udev, ep);
1545         size = stream->ctrl.dwMaxVideoFrameSize;
1546
1547         npackets = uvc_alloc_urb_buffers(stream, size, psize, gfp_flags);
1548         if (npackets == 0)
1549                 return -ENOMEM;
1550
1551         size = npackets * psize;
1552
1553         for (i = 0; i < UVC_URBS; ++i) {
1554                 urb = usb_alloc_urb(npackets, gfp_flags);
1555                 if (urb == NULL) {
1556                         uvc_uninit_video(stream, 1);
1557                         return -ENOMEM;
1558                 }
1559
1560                 urb->dev = stream->dev->udev;
1561                 urb->context = stream;
1562                 urb->pipe = usb_rcvisocpipe(stream->dev->udev,
1563                                 ep->desc.bEndpointAddress);
1564 #ifndef CONFIG_DMA_NONCOHERENT
1565                 urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
1566                 urb->transfer_dma = stream->urb_dma[i];
1567 #else
1568                 urb->transfer_flags = URB_ISO_ASAP;
1569 #endif
1570                 urb->interval = ep->desc.bInterval;
1571                 urb->transfer_buffer = stream->urb_buffer[i];
1572                 urb->complete = uvc_video_complete;
1573                 urb->number_of_packets = npackets;
1574                 urb->transfer_buffer_length = size;
1575
1576                 for (j = 0; j < npackets; ++j) {
1577                         urb->iso_frame_desc[j].offset = j * psize;
1578                         urb->iso_frame_desc[j].length = psize;
1579                 }
1580
1581                 stream->urb[i] = urb;
1582                 /* ddl@rock-chips.com  */
1583                 atomic_set(&stream->urb_state[i],UrbActive);
1584                 stream->tasklet[i] = kmalloc(sizeof(struct tasklet_struct), GFP_KERNEL);
1585                 if (stream->tasklet[i] == NULL) {
1586                         uvc_printk(KERN_ERR, "device %s requested tasklet memory fail!\n",
1587                                 stream->dev->name);
1588                 } else {
1589                         tasklet_init(stream->tasklet[i], uvc_video_complete_tasklet, (unsigned long)urb);
1590                 }
1591         }
1592
1593         return 0;
1594 }
1595
1596 /*
1597  * Initialize bulk URBs and allocate transfer buffers. The packet size is
1598  * given by the endpoint.
1599  */
1600 static int uvc_init_video_bulk(struct uvc_streaming *stream,
1601         struct usb_host_endpoint *ep, gfp_t gfp_flags)
1602 {
1603         struct urb *urb;
1604         unsigned int npackets, pipe, i;
1605         u16 psize;
1606         u32 size;
1607
1608         psize = usb_endpoint_maxp(&ep->desc) & 0x7ff;
1609         size = stream->ctrl.dwMaxPayloadTransferSize;
1610         stream->bulk.max_payload_size = size;
1611
1612         npackets = uvc_alloc_urb_buffers(stream, size, psize, gfp_flags);
1613         if (npackets == 0)
1614                 return -ENOMEM;
1615
1616         size = npackets * psize;
1617
1618         if (usb_endpoint_dir_in(&ep->desc))
1619                 pipe = usb_rcvbulkpipe(stream->dev->udev,
1620                                        ep->desc.bEndpointAddress);
1621         else
1622                 pipe = usb_sndbulkpipe(stream->dev->udev,
1623                                        ep->desc.bEndpointAddress);
1624
1625         if (stream->type == V4L2_BUF_TYPE_VIDEO_OUTPUT)
1626                 size = 0;
1627
1628         for (i = 0; i < UVC_URBS; ++i) {
1629                 urb = usb_alloc_urb(0, gfp_flags);
1630                 if (urb == NULL) {
1631                         uvc_uninit_video(stream, 1);
1632                         return -ENOMEM;
1633                 }
1634
1635                 usb_fill_bulk_urb(urb, stream->dev->udev, pipe,
1636                         stream->urb_buffer[i], size, uvc_video_complete,
1637                         stream);
1638 #ifndef CONFIG_DMA_NONCOHERENT
1639                 urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1640                 urb->transfer_dma = stream->urb_dma[i];
1641 #endif
1642
1643                 stream->urb[i] = urb;
1644
1645                 /* ddl@rock-chips.com  */
1646                 stream->tasklet[i] = kmalloc(sizeof(struct tasklet_struct), GFP_KERNEL);
1647                 if (stream->tasklet[i] == NULL) {
1648                         uvc_printk(KERN_ERR, "device %s requested tasklet memory fail!\n",
1649                                 stream->dev->name);
1650                 } else {
1651                         tasklet_init(stream->tasklet[i], uvc_video_complete_tasklet, (unsigned long)urb);
1652                 }
1653         }
1654
1655         return 0;
1656 }
1657
1658 /*
1659  * Initialize isochronous/bulk URBs and allocate transfer buffers.
1660  */
1661 static int uvc_init_video(struct uvc_streaming *stream, gfp_t gfp_flags)
1662 {
1663         struct usb_interface *intf = stream->intf;
1664         struct usb_host_endpoint *ep;
1665         unsigned int i;
1666         int ret;
1667
1668         stream->sequence = -1;
1669         stream->last_fid = -1;
1670         stream->bulk.header_size = 0;
1671         stream->bulk.skip_payload = 0;
1672         stream->bulk.payload_size = 0;
1673
1674         uvc_video_stats_start(stream);
1675
1676         if (intf->num_altsetting > 1) {
1677                 struct usb_host_endpoint *best_ep = NULL;
1678                 unsigned int best_psize = UINT_MAX;
1679                 unsigned int bandwidth;
1680                 unsigned int uninitialized_var(altsetting);
1681                 int intfnum = stream->intfnum;
1682
1683                 /* Isochronous endpoint, select the alternate setting. */
1684                 bandwidth = stream->ctrl.dwMaxPayloadTransferSize;
1685
1686                 if (bandwidth == 0) {
1687                         uvc_trace(UVC_TRACE_VIDEO, "Device requested null "
1688                                 "bandwidth, defaulting to lowest.\n");
1689                         bandwidth = 1;
1690                 } else {
1691                         uvc_trace(UVC_TRACE_VIDEO, "Device requested %u "
1692                                 "B/frame bandwidth.\n", bandwidth);
1693                 }
1694
1695                 for (i = 0; i < intf->num_altsetting; ++i) {
1696                         struct usb_host_interface *alts;
1697                         unsigned int psize;
1698
1699                         alts = &intf->altsetting[i];
1700                         ep = uvc_find_endpoint(alts,
1701                                 stream->header.bEndpointAddress);
1702                         if (ep == NULL)
1703                                 continue;
1704
1705                         /* Check if the bandwidth is high enough. */
1706                         psize = uvc_endpoint_max_bpi(stream->dev->udev, ep);
1707                         if (psize >= bandwidth && psize <= best_psize) {
1708                                 altsetting = alts->desc.bAlternateSetting;
1709                                 best_psize = psize;
1710                                 best_ep = ep;
1711                         }
1712                 }
1713
1714                 if (best_ep == NULL) {
1715                         uvc_trace(UVC_TRACE_VIDEO, "No fast enough alt setting "
1716                                 "for requested bandwidth.\n");
1717                         return -EIO;
1718                 }
1719
1720                 uvc_trace(UVC_TRACE_VIDEO, "Selecting alternate setting %u "
1721                         "(%u B/frame bandwidth).\n", altsetting, best_psize);
1722
1723                 ret = usb_set_interface(stream->dev->udev, intfnum, altsetting);
1724                 if (ret < 0)
1725                         return ret;
1726
1727                 ret = uvc_init_video_isoc(stream, best_ep, gfp_flags);
1728         } else {
1729                 /* Bulk endpoint, proceed to URB initialization. */
1730                 ep = uvc_find_endpoint(&intf->altsetting[0],
1731                                 stream->header.bEndpointAddress);
1732                 if (ep == NULL)
1733                         return -EIO;
1734
1735                 ret = uvc_init_video_bulk(stream, ep, gfp_flags);
1736         }
1737
1738         if (ret < 0)
1739                 return ret;
1740
1741         /* Submit the URBs. */
1742         for (i = 0; i < UVC_URBS; ++i) {
1743                 ret = usb_submit_urb(stream->urb[i], gfp_flags);
1744                 if (ret < 0) {
1745                         uvc_printk(KERN_ERR, "Failed to submit URB %u "
1746                                         "(%d).\n", i, ret);
1747                         uvc_uninit_video(stream, 1);
1748                         return ret;
1749                 }
1750         }
1751
1752         return 0;
1753 }
1754
1755 /* --------------------------------------------------------------------------
1756  * Suspend/resume
1757  */
1758
1759 /*
1760  * Stop streaming without disabling the video queue.
1761  *
1762  * To let userspace applications resume without trouble, we must not touch the
1763  * video buffers in any way. We mark the device as frozen to make sure the URB
1764  * completion handler won't try to cancel the queue when we kill the URBs.
1765  */
1766 int uvc_video_suspend(struct uvc_streaming *stream)
1767 {
1768         if (!uvc_queue_streaming(&stream->queue))
1769                 return 0;
1770
1771         stream->frozen = 1;
1772         uvc_uninit_video(stream, 0);
1773         usb_set_interface(stream->dev->udev, stream->intfnum, 0);
1774         return 0;
1775 }
1776
1777 /*
1778  * Reconfigure the video interface and restart streaming if it was enabled
1779  * before suspend.
1780  *
1781  * If an error occurs, disable the video queue. This will wake all pending
1782  * buffers, making sure userspace applications are notified of the problem
1783  * instead of waiting forever.
1784  */
1785 int uvc_video_resume(struct uvc_streaming *stream, int reset)
1786 {
1787         int ret;
1788
1789         /* If the bus has been reset on resume, set the alternate setting to 0.
1790          * This should be the default value, but some devices crash or otherwise
1791          * misbehave if they don't receive a SET_INTERFACE request before any
1792          * other video control request.
1793          */
1794         if (reset)
1795                 usb_set_interface(stream->dev->udev, stream->intfnum, 0);
1796
1797         stream->frozen = 0;
1798
1799         uvc_video_clock_reset(stream);
1800
1801         ret = uvc_commit_video(stream, &stream->ctrl);
1802         if (ret < 0) {
1803                 uvc_queue_enable(&stream->queue, 0);
1804                 return ret;
1805         }
1806
1807         if (!uvc_queue_streaming(&stream->queue))
1808                 return 0;
1809
1810         ret = uvc_init_video(stream, GFP_NOIO);
1811         if (ret < 0)
1812                 uvc_queue_enable(&stream->queue, 0);
1813
1814         return ret;
1815 }
1816
1817 /* ------------------------------------------------------------------------
1818  * Video device
1819  */
1820
1821 /*
1822  * Initialize the UVC video device by switching to alternate setting 0 and
1823  * retrieve the default format.
1824  *
1825  * Some cameras (namely the Fuji Finepix) set the format and frame
1826  * indexes to zero. The UVC standard doesn't clearly make this a spec
1827  * violation, so try to silently fix the values if possible.
1828  *
1829  * This function is called before registering the device with V4L.
1830  */
1831 int uvc_video_init(struct uvc_streaming *stream)
1832 {
1833         struct uvc_streaming_control *probe = &stream->ctrl;
1834         struct uvc_format *format = NULL;
1835         struct uvc_frame *frame = NULL;
1836         unsigned int i;
1837         int ret;
1838
1839         if (stream->nformats == 0) {
1840                 uvc_printk(KERN_INFO, "No supported video formats found.\n");
1841                 return -EINVAL;
1842         }
1843
1844         atomic_set(&stream->active, 0);
1845
1846         /* Initialize the video buffers queue. */
1847         ret = uvc_queue_init(&stream->queue, stream->type, !uvc_no_drop_param);
1848         if (ret)
1849                 return ret;
1850
1851         /* Alternate setting 0 should be the default, yet the XBox Live Vision
1852          * Cam (and possibly other devices) crash or otherwise misbehave if
1853          * they don't receive a SET_INTERFACE request before any other video
1854          * control request.
1855          */
1856         usb_set_interface(stream->dev->udev, stream->intfnum, 0);
1857
1858         /* Set the streaming probe control with default streaming parameters
1859          * retrieved from the device. Webcams that don't suport GET_DEF
1860          * requests on the probe control will just keep their current streaming
1861          * parameters.
1862          */
1863         if (uvc_get_video_ctrl(stream, probe, 1, UVC_GET_DEF) == 0)
1864                 uvc_set_video_ctrl(stream, probe, 1);
1865
1866         /* Initialize the streaming parameters with the probe control current
1867          * value. This makes sure SET_CUR requests on the streaming commit
1868          * control will always use values retrieved from a successful GET_CUR
1869          * request on the probe control, as required by the UVC specification.
1870          */
1871         ret = uvc_get_video_ctrl(stream, probe, 1, UVC_GET_CUR);
1872         if (ret < 0)
1873                 return ret;
1874
1875         /* Check if the default format descriptor exists. Use the first
1876          * available format otherwise.
1877          */
1878         for (i = stream->nformats; i > 0; --i) {
1879                 format = &stream->format[i-1];
1880                 if (format->index == probe->bFormatIndex)
1881                         break;
1882         }
1883
1884         if (format->nframes == 0) {
1885                 uvc_printk(KERN_INFO, "No frame descriptor found for the "
1886                         "default format.\n");
1887                 return -EINVAL;
1888         }
1889
1890         /* Zero bFrameIndex might be correct. Stream-based formats (including
1891          * MPEG-2 TS and DV) do not support frames but have a dummy frame
1892          * descriptor with bFrameIndex set to zero. If the default frame
1893          * descriptor is not found, use the first available frame.
1894          */
1895         for (i = format->nframes; i > 0; --i) {
1896                 frame = &format->frame[i-1];
1897                 if (frame->bFrameIndex == probe->bFrameIndex)
1898                         break;
1899         }
1900
1901         probe->bFormatIndex = format->index;
1902         probe->bFrameIndex = frame->bFrameIndex;
1903
1904         stream->def_format = format;
1905         stream->cur_format = format;
1906         stream->cur_frame = frame;
1907
1908         /* Select the video decoding function */
1909         if (stream->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) {
1910                 if (stream->dev->quirks & UVC_QUIRK_BUILTIN_ISIGHT)
1911                         stream->decode = uvc_video_decode_isight;
1912                 else if (stream->intf->num_altsetting > 1)
1913                         stream->decode = uvc_video_decode_isoc;
1914                 else
1915                         stream->decode = uvc_video_decode_bulk;
1916         } else {
1917                 if (stream->intf->num_altsetting == 1)
1918                         stream->decode = uvc_video_encode_bulk;
1919                 else {
1920                         uvc_printk(KERN_INFO, "Isochronous endpoints are not "
1921                                 "supported for video output devices.\n");
1922                         return -EINVAL;
1923                 }
1924         }
1925
1926         return 0;
1927 }
1928
1929 /*
1930  * Enable or disable the video stream.
1931  */
1932 int uvc_video_enable(struct uvc_streaming *stream, int enable)
1933 {
1934         int ret;
1935
1936         if (!enable) {
1937                 uvc_uninit_video(stream, 1);
1938                 if (stream->intf->num_altsetting > 1) {
1939                         usb_set_interface(stream->dev->udev,
1940                                           stream->intfnum, 0);
1941                 } else {
1942                         /* UVC doesn't specify how to inform a bulk-based device
1943                          * when the video stream is stopped. Windows sends a
1944                          * CLEAR_FEATURE(HALT) request to the video streaming
1945                          * bulk endpoint, mimic the same behaviour.
1946                          */
1947                         unsigned int epnum = stream->header.bEndpointAddress
1948                                            & USB_ENDPOINT_NUMBER_MASK;
1949                         unsigned int dir = stream->header.bEndpointAddress
1950                                          & USB_ENDPOINT_DIR_MASK;
1951                         unsigned int pipe;
1952
1953                         pipe = usb_sndbulkpipe(stream->dev->udev, epnum) | dir;
1954                         usb_clear_halt(stream->dev->udev, pipe);
1955                 }
1956
1957                 uvc_queue_enable(&stream->queue, 0);
1958                 uvc_video_clock_cleanup(stream);
1959                 return 0;
1960         }
1961
1962         ret = uvc_video_clock_init(stream);
1963         if (ret < 0)
1964                 return ret;
1965
1966         ret = uvc_queue_enable(&stream->queue, 1);
1967         if (ret < 0)
1968                 goto error_queue;
1969
1970         /* Commit the streaming parameters. */
1971         ret = uvc_commit_video(stream, &stream->ctrl);
1972         if (ret < 0)
1973                 goto error_commit;
1974
1975         ret = uvc_init_video(stream, GFP_KERNEL);
1976         if (ret < 0)
1977                 goto error_video;
1978
1979         return 0;
1980
1981 error_video:
1982         usb_set_interface(stream->dev->udev, stream->intfnum, 0);
1983 error_commit:
1984         uvc_queue_enable(&stream->queue, 0);
1985 error_queue:
1986         uvc_video_clock_cleanup(stream);
1987
1988         return ret;
1989 }