drivers/usb/host/ehci-sched.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (c) 2001-2004 by David Brownell
   4  * Copyright (c) 2003 Michal Sojka, for high-speed iso transfers
   5  */
   6
   7 /* this file is part of ehci-hcd.c */
   8
   9 /*-------------------------------------------------------------------------*/
  10
  11 /*
  12  * EHCI scheduled transaction support:  interrupt, iso, split iso
  13  * These are called "periodic" transactions in the EHCI spec.
  14  *
  15  * Note that for interrupt transfers, the QH/QTD manipulation is shared
  16  * with the "asynchronous" transaction support (control/bulk transfers).
  17  * The only real difference is in how interrupt transfers are scheduled.
  18  *
  19  * For ISO, we make an "iso_stream" head to serve the same role as a QH.
  20  * It keeps track of every ITD (or SITD) that's linked, and holds enough
  21  * pre-calculated schedule data to make appending to the queue be quick.
  22  */
  23
  24 static int ehci_get_frame(struct usb_hcd *hcd);
  25
  26 /*
  27  * periodic_next_shadow - return "next" pointer on shadow list
  28  * @periodic: host pointer to qh/itd/sitd
  29  * @tag: hardware tag for type of this record
  30  */
  31 static union ehci_shadow *
  32 periodic_next_shadow(struct ehci_hcd *ehci, union ehci_shadow *periodic,
  33                 __hc32 tag)
  34 {
  35         switch (hc32_to_cpu(ehci, tag)) {
  36         case Q_TYPE_QH:
  37                 return &periodic->qh->qh_next;
  38         case Q_TYPE_FSTN:
  39                 return &periodic->fstn->fstn_next;
  40         case Q_TYPE_ITD:
  41                 return &periodic->itd->itd_next;
  42         /* case Q_TYPE_SITD: */
  43         default:
  44                 return &periodic->sitd->sitd_next;
  45         }
  46 }
  47
  48 static __hc32 *
  49 shadow_next_periodic(struct ehci_hcd *ehci, union ehci_shadow *periodic,
  50                 __hc32 tag)
  51 {
  52         switch (hc32_to_cpu(ehci, tag)) {
  53         /* our ehci_shadow.qh is actually software part */
  54         case Q_TYPE_QH:
  55                 return &periodic->qh->hw->hw_next;
  56         /* others are hw parts */
  57         default:
  58                 return periodic->hw_next;
  59         }
  60 }
  61
  62 /* caller must hold ehci->lock */
  63 static void periodic_unlink(struct ehci_hcd *ehci, unsigned frame, void *ptr)
  64 {
  65         union ehci_shadow       *prev_p = &ehci->pshadow[frame];
  66         __hc32                  *hw_p = &ehci->periodic[frame];
  67         union ehci_shadow       here = *prev_p;
  68
  69         /* find predecessor of "ptr"; hw and shadow lists are in sync */
  70         while (here.ptr && here.ptr != ptr) {
  71                 prev_p = periodic_next_shadow(ehci, prev_p,
  72                                 Q_NEXT_TYPE(ehci, *hw_p));
  73                 hw_p = shadow_next_periodic(ehci, &here,
  74                                 Q_NEXT_TYPE(ehci, *hw_p));
  75                 here = *prev_p;
  76         }
  77         /* an interrupt entry (at list end) could have been shared */
  78         if (!here.ptr)
  79                 return;
  80
  81         /* update shadow and hardware lists ... the old "next" pointers
  82          * from ptr may still be in use, the caller updates them.
  83          */
  84         *prev_p = *periodic_next_shadow(ehci, &here,
  85                         Q_NEXT_TYPE(ehci, *hw_p));
  86
  87         if (!ehci->use_dummy_qh ||
  88             *shadow_next_periodic(ehci, &here, Q_NEXT_TYPE(ehci, *hw_p))
  89                         != EHCI_LIST_END(ehci))
  90                 *hw_p = *shadow_next_periodic(ehci, &here,
  91                                 Q_NEXT_TYPE(ehci, *hw_p));
  92         else
  93                 *hw_p = cpu_to_hc32(ehci, ehci->dummy->qh_dma);
  94 }
  95
  96 /*-------------------------------------------------------------------------*/
  97
  98 /* Bandwidth and TT management */
  99
 100 /* Find the TT data structure for this device; create it if necessary */
 101 static struct ehci_tt *find_tt(struct usb_device *udev)
 102 {
 103         struct usb_tt           *utt = udev->tt;
 104         struct ehci_tt          *tt, **tt_index, **ptt;
 105         unsigned                port;
 106         bool                    allocated_index = false;
 107
 108         if (!utt)
 109                 return NULL;            /* Not below a TT */
 110
 111         /*
 112          * Find/create our data structure.
 113          * For hubs with a single TT, we get it directly.
 114          * For hubs with multiple TTs, there's an extra level of pointers.
 115          */
 116         tt_index = NULL;
 117         if (utt->multi) {
 118                 tt_index = utt->hcpriv;
 119                 if (!tt_index) {                /* Create the index array */
 120                         tt_index = kcalloc(utt->hub->maxchild,
 121                                            sizeof(*tt_index),
 122                                            GFP_ATOMIC);
 123                         if (!tt_index)
 124                                 return ERR_PTR(-ENOMEM);
 125                         utt->hcpriv = tt_index;
 126                         allocated_index = true;
 127                 }
 128                 port = udev->ttport - 1;
 129                 ptt = &tt_index[port];
 130         } else {
 131                 port = 0;
 132                 ptt = (struct ehci_tt **) &utt->hcpriv;
 133         }
 134
 135         tt = *ptt;
 136         if (!tt) {                              /* Create the ehci_tt */
 137                 struct ehci_hcd         *ehci =
 138                                 hcd_to_ehci(bus_to_hcd(udev->bus));
 139
 140                 tt = kzalloc(sizeof(*tt), GFP_ATOMIC);
 141                 if (!tt) {
 142                         if (allocated_index) {
 143                                 utt->hcpriv = NULL;
 144                                 kfree(tt_index);
 145                         }
 146                         return ERR_PTR(-ENOMEM);
 147                 }
 148                 list_add_tail(&tt->tt_list, &ehci->tt_list);
 149                 INIT_LIST_HEAD(&tt->ps_list);
 150                 tt->usb_tt = utt;
 151                 tt->tt_port = port;
 152                 *ptt = tt;
 153         }
 154
 155         return tt;
 156 }
 157
 158 /* Release the TT above udev, if it's not in use */
 159 static void drop_tt(struct usb_device *udev)
 160 {
 161         struct usb_tt           *utt = udev->tt;
 162         struct ehci_tt          *tt, **tt_index, **ptt;
 163         int                     cnt, i;
 164
 165         if (!utt || !utt->hcpriv)
 166                 return;         /* Not below a TT, or never allocated */
 167
 168         cnt = 0;
 169         if (utt->multi) {
 170                 tt_index = utt->hcpriv;
 171                 ptt = &tt_index[udev->ttport - 1];
 172
 173                 /* How many entries are left in tt_index? */
 174                 for (i = 0; i < utt->hub->maxchild; ++i)
 175                         cnt += !!tt_index[i];
 176         } else {
 177                 tt_index = NULL;
 178                 ptt = (struct ehci_tt **) &utt->hcpriv;
 179         }
 180
 181         tt = *ptt;
 182         if (!tt || !list_empty(&tt->ps_list))
 183                 return;         /* never allocated, or still in use */
 184
 185         list_del(&tt->tt_list);
 186         *ptt = NULL;
 187         kfree(tt);
 188         if (cnt == 1) {
 189                 utt->hcpriv = NULL;
 190                 kfree(tt_index);
 191         }
 192 }
 193
 194 static void bandwidth_dbg(struct ehci_hcd *ehci, int sign, char *type,
 195                 struct ehci_per_sched *ps)
 196 {
 197         dev_dbg(&ps->udev->dev,
 198                         "ep %02x: %s %s @ %u+%u (%u.%u+%u) [%u/%u us] mask %04x\n",
 199                         ps->ep->desc.bEndpointAddress,
 200                         (sign >= 0 ? "reserve" : "release"), type,
 201                         (ps->bw_phase << 3) + ps->phase_uf, ps->bw_uperiod,
 202                         ps->phase, ps->phase_uf, ps->period,
 203                         ps->usecs, ps->c_usecs, ps->cs_mask);
 204 }
 205
 206 static void reserve_release_intr_bandwidth(struct ehci_hcd *ehci,
 207                 struct ehci_qh *qh, int sign)
 208 {
 209         unsigned                start_uf;
 210         unsigned                i, j, m;
 211         int                     usecs = qh->ps.usecs;
 212         int                     c_usecs = qh->ps.c_usecs;
 213         int                     tt_usecs = qh->ps.tt_usecs;
 214         struct ehci_tt          *tt;
 215
 216         if (qh->ps.phase == NO_FRAME)   /* Bandwidth wasn't reserved */
 217                 return;
 218         start_uf = qh->ps.bw_phase << 3;
 219
 220         bandwidth_dbg(ehci, sign, "intr", &qh->ps);
 221
 222         if (sign < 0) {         /* Release bandwidth */
 223                 usecs = -usecs;
 224                 c_usecs = -c_usecs;
 225                 tt_usecs = -tt_usecs;
 226         }
 227
 228         /* Entire transaction (high speed) or start-split (full/low speed) */
 229         for (i = start_uf + qh->ps.phase_uf; i < EHCI_BANDWIDTH_SIZE;
 230                         i += qh->ps.bw_uperiod)
 231                 ehci->bandwidth[i] += usecs;
 232
 233         /* Complete-split (full/low speed) */
 234         if (qh->ps.c_usecs) {
 235                 /* NOTE: adjustments needed for FSTN */
 236                 for (i = start_uf; i < EHCI_BANDWIDTH_SIZE;
 237                                 i += qh->ps.bw_uperiod) {
 238                         for ((j = 2, m = 1 << (j+8)); j < 8; (++j, m <<= 1)) {
 239                                 if (qh->ps.cs_mask & m)
 240                                         ehci->bandwidth[i+j] += c_usecs;
 241                         }
 242                 }
 243         }
 244
 245         /* FS/LS bus bandwidth */
 246         if (tt_usecs) {
 247                 tt = find_tt(qh->ps.udev);
 248                 if (sign > 0)
 249                         list_add_tail(&qh->ps.ps_list, &tt->ps_list);
 250                 else
 251                         list_del(&qh->ps.ps_list);
 252
 253                 for (i = start_uf >> 3; i < EHCI_BANDWIDTH_FRAMES;
 254                                 i += qh->ps.bw_period)
 255                         tt->bandwidth[i] += tt_usecs;
 256         }
 257 }
 258
 259 /*-------------------------------------------------------------------------*/
 260
 261 static void compute_tt_budget(u8 budget_table[EHCI_BANDWIDTH_SIZE],
 262                 struct ehci_tt *tt)
 263 {
 264         struct ehci_per_sched   *ps;
 265         unsigned                uframe, uf, x;
 266         u8                      *budget_line;
 267
 268         if (!tt)
 269                 return;
 270         memset(budget_table, 0, EHCI_BANDWIDTH_SIZE);
 271
 272         /* Add up the contributions from all the endpoints using this TT */
 273         list_for_each_entry(ps, &tt->ps_list, ps_list) {
 274                 for (uframe = ps->bw_phase << 3; uframe < EHCI_BANDWIDTH_SIZE;
 275                                 uframe += ps->bw_uperiod) {
 276                         budget_line = &budget_table[uframe];
 277                         x = ps->tt_usecs;
 278
 279                         /* propagate the time forward */
 280                         for (uf = ps->phase_uf; uf < 8; ++uf) {
 281                                 x += budget_line[uf];
 282
 283                                 /* Each microframe lasts 125 us */
 284                                 if (x <= 125) {
 285                                         budget_line[uf] = x;
 286                                         break;
 287                                 }
 288                                 budget_line[uf] = 125;
 289                                 x -= 125;
 290                         }
 291                 }
 292         }
 293 }
 294
 295 static int __maybe_unused same_tt(struct usb_device *dev1,
 296                 struct usb_device *dev2)
 297 {
 298         if (!dev1->tt || !dev2->tt)
 299                 return 0;
 300         if (dev1->tt != dev2->tt)
 301                 return 0;
 302         if (dev1->tt->multi)
 303                 return dev1->ttport == dev2->ttport;
 304         else
 305                 return 1;
 306 }
 307
 308 #ifdef CONFIG_USB_EHCI_TT_NEWSCHED
 309
 310 /* Which uframe does the low/fullspeed transfer start in?
 311  *
 312  * The parameter is the mask of ssplits in "H-frame" terms
 313  * and this returns the transfer start uframe in "B-frame" terms,
 314  * which allows both to match, e.g. a ssplit in "H-frame" uframe 0
 315  * will cause a transfer in "B-frame" uframe 0.  "B-frames" lag
 316  * "H-frames" by 1 uframe.  See the EHCI spec sec 4.5 and figure 4.7.
 317  */
 318 static inline unsigned char tt_start_uframe(struct ehci_hcd *ehci, __hc32 mask)
 319 {
 320         unsigned char smask = hc32_to_cpu(ehci, mask) & QH_SMASK;
 321
 322         if (!smask) {
 323                 ehci_err(ehci, "invalid empty smask!\n");
 324                 /* uframe 7 can't have bw so this will indicate failure */
 325                 return 7;
 326         }
 327         return ffs(smask) - 1;
 328 }
 329
 330 static const unsigned char
 331 max_tt_usecs[] = { 125, 125, 125, 125, 125, 125, 30, 0 };
 332
 333 /* carryover low/fullspeed bandwidth that crosses uframe boundries */
 334 static inline void carryover_tt_bandwidth(unsigned short tt_usecs[8])
 335 {
 336         int i;
 337
 338         for (i = 0; i < 7; i++) {
 339                 if (max_tt_usecs[i] < tt_usecs[i]) {
 340                         tt_usecs[i+1] += tt_usecs[i] - max_tt_usecs[i];
 341                         tt_usecs[i] = max_tt_usecs[i];
 342                 }
 343         }
 344 }
 345
 346 /*
 347  * Return true if the device's tt's downstream bus is available for a
 348  * periodic transfer of the specified length (usecs), starting at the
 349  * specified frame/uframe.  Note that (as summarized in section 11.19
 350  * of the usb 2.0 spec) TTs can buffer multiple transactions for each
 351  * uframe.
 352  *
 353  * The uframe parameter is when the fullspeed/lowspeed transfer
 354  * should be executed in "B-frame" terms, which is the same as the
 355  * highspeed ssplit's uframe (which is in "H-frame" terms).  For example
 356  * a ssplit in "H-frame" 0 causes a transfer in "B-frame" 0.
 357  * See the EHCI spec sec 4.5 and fig 4.7.
 358  *
 359  * This checks if the full/lowspeed bus, at the specified starting uframe,
 360  * has the specified bandwidth available, according to rules listed
 361  * in USB 2.0 spec section 11.18.1 fig 11-60.
 362  *
 363  * This does not check if the transfer would exceed the max ssplit
 364  * limit of 16, specified in USB 2.0 spec section 11.18.4 requirement #4,
 365  * since proper scheduling limits ssplits to less than 16 per uframe.
 366  */
 367 static int tt_available(
 368         struct ehci_hcd         *ehci,
 369         struct ehci_per_sched   *ps,
 370         struct ehci_tt          *tt,
 371         unsigned                frame,
 372         unsigned                uframe
 373 )
 374 {
 375         unsigned                period = ps->bw_period;
 376         unsigned                usecs = ps->tt_usecs;
 377
 378         if ((period == 0) || (uframe >= 7))     /* error */
 379                 return 0;
 380
 381         for (frame &= period - 1; frame < EHCI_BANDWIDTH_FRAMES;
 382                         frame += period) {
 383                 unsigned        i, uf;
 384                 unsigned short  tt_usecs[8];
 385
 386                 if (tt->bandwidth[frame] + usecs > 900)
 387                         return 0;
 388
 389                 uf = frame << 3;
 390                 for (i = 0; i < 8; (++i, ++uf))
 391                         tt_usecs[i] = ehci->tt_budget[uf];
 392
 393                 if (max_tt_usecs[uframe] <= tt_usecs[uframe])
 394                         return 0;
 395
 396                 /* special case for isoc transfers larger than 125us:
 397                  * the first and each subsequent fully used uframe
 398                  * must be empty, so as to not illegally delay
 399                  * already scheduled transactions
 400                  */
 401                 if (usecs > 125) {
 402                         int ufs = (usecs / 125);
 403
 404                         for (i = uframe; i < (uframe + ufs) && i < 8; i++)
 405                                 if (tt_usecs[i] > 0)
 406                                         return 0;
 407                 }
 408
 409                 tt_usecs[uframe] += usecs;
 410
 411                 carryover_tt_bandwidth(tt_usecs);
 412
 413                 /* fail if the carryover pushed bw past the last uframe's limit */
 414                 if (max_tt_usecs[7] < tt_usecs[7])
 415                         return 0;
 416         }
 417
 418         return 1;
 419 }
 420
 421 #else
 422
 423 /* return true iff the device's transaction translator is available
 424  * for a periodic transfer starting at the specified frame, using
 425  * all the uframes in the mask.
 426  */
 427 static int tt_no_collision(
 428         struct ehci_hcd         *ehci,
 429         unsigned                period,
 430         struct usb_device       *dev,
 431         unsigned                frame,
 432         u32                     uf_mask
 433 )
 434 {
 435         if (period == 0)        /* error */
 436                 return 0;
 437
 438         /* note bandwidth wastage:  split never follows csplit
 439          * (different dev or endpoint) until the next uframe.
 440          * calling convention doesn't make that distinction.
 441          */
 442         for (; frame < ehci->periodic_size; frame += period) {
 443                 union ehci_shadow       here;
 444                 __hc32                  type;
 445                 struct ehci_qh_hw       *hw;
 446
 447                 here = ehci->pshadow[frame];
 448                 type = Q_NEXT_TYPE(ehci, ehci->periodic[frame]);
 449                 while (here.ptr) {
 450                         switch (hc32_to_cpu(ehci, type)) {
 451                         case Q_TYPE_ITD:
 452                                 type = Q_NEXT_TYPE(ehci, here.itd->hw_next);
 453                                 here = here.itd->itd_next;
 454                                 continue;
 455                         case Q_TYPE_QH:
 456                                 hw = here.qh->hw;
 457                                 if (same_tt(dev, here.qh->ps.udev)) {
 458                                         u32             mask;
 459
 460                                         mask = hc32_to_cpu(ehci,
 461                                                         hw->hw_info2);
 462                                         /* "knows" no gap is needed */
 463                                         mask |= mask >> 8;
 464                                         if (mask & uf_mask)
 465                                                 break;
 466                                 }
 467                                 type = Q_NEXT_TYPE(ehci, hw->hw_next);
 468                                 here = here.qh->qh_next;
 469                                 continue;
 470                         case Q_TYPE_SITD:
 471                                 if (same_tt(dev, here.sitd->urb->dev)) {
 472                                         u16             mask;
 473
 474                                         mask = hc32_to_cpu(ehci, here.sitd
 475                                                                 ->hw_uframe);
 476                                         /* FIXME assumes no gap for IN! */
 477                                         mask |= mask >> 8;
 478                                         if (mask & uf_mask)
 479                                                 break;
 480                                 }
 481                                 type = Q_NEXT_TYPE(ehci, here.sitd->hw_next);
 482                                 here = here.sitd->sitd_next;
 483                                 continue;
 484                         /* case Q_TYPE_FSTN: */
 485                         default:
 486                                 ehci_dbg(ehci,
 487                                         "periodic frame %d bogus type %d\n",
 488                                         frame, type);
 489                         }
 490
 491                         /* collision or error */
 492                         return 0;
 493                 }
 494         }
 495
 496         /* no collision */
 497         return 1;
 498 }
 499
 500 #endif /* CONFIG_USB_EHCI_TT_NEWSCHED */
 501
 502 /*-------------------------------------------------------------------------*/
 503
 504 static void enable_periodic(struct ehci_hcd *ehci)
 505 {
 506         if (ehci->periodic_count++)
 507                 return;
 508
 509         /* Stop waiting to turn off the periodic schedule */
 510         ehci->enabled_hrtimer_events &= ~BIT(EHCI_HRTIMER_DISABLE_PERIODIC);
 511
 512         /* Don't start the schedule until PSS is 0 */
 513         ehci_poll_PSS(ehci);
 514         turn_on_io_watchdog(ehci);
 515 }
 516
 517 static void disable_periodic(struct ehci_hcd *ehci)
 518 {
 519         if (--ehci->periodic_count)
 520                 return;
 521
 522         /* Don't turn off the schedule until PSS is 1 */
 523         ehci_poll_PSS(ehci);
 524 }
 525
 526 /*-------------------------------------------------------------------------*/
 527
 528 /* periodic schedule slots have iso tds (normal or split) first, then a
 529  * sparse tree for active interrupt transfers.
 530  *
 531  * this just links in a qh; caller guarantees uframe masks are set right.
 532  * no FSTN support (yet; ehci 0.96+)
 533  */
 534 static void qh_link_periodic(struct ehci_hcd *ehci, struct ehci_qh *qh)
 535 {
 536         unsigned        i;
 537         unsigned        period = qh->ps.period;
 538
 539         dev_dbg(&qh->ps.udev->dev,
 540                 "link qh%d-%04x/%p start %d [%d/%d us]\n",
 541                 period, hc32_to_cpup(ehci, &qh->hw->hw_info2)
 542                         & (QH_CMASK | QH_SMASK),
 543                 qh, qh->ps.phase, qh->ps.usecs, qh->ps.c_usecs);
 544
 545         /* high bandwidth, or otherwise every microframe */
 546         if (period == 0)
 547                 period = 1;
 548
 549         for (i = qh->ps.phase; i < ehci->periodic_size; i += period) {
 550                 union ehci_shadow       *prev = &ehci->pshadow[i];
 551                 __hc32                  *hw_p = &ehci->periodic[i];
 552                 union ehci_shadow       here = *prev;
 553                 __hc32                  type = 0;
 554
 555                 /* skip the iso nodes at list head */
 556                 while (here.ptr) {
 557                         type = Q_NEXT_TYPE(ehci, *hw_p);
 558                         if (type == cpu_to_hc32(ehci, Q_TYPE_QH))
 559                                 break;
 560                         prev = periodic_next_shadow(ehci, prev, type);
 561                         hw_p = shadow_next_periodic(ehci, &here, type);
 562                         here = *prev;
 563                 }
 564
 565                 /* sorting each branch by period (slow-->fast)
 566                  * enables sharing interior tree nodes
 567                  */
 568                 while (here.ptr && qh != here.qh) {
 569                         if (qh->ps.period > here.qh->ps.period)
 570                                 break;
 571                         prev = &here.qh->qh_next;
 572                         hw_p = &here.qh->hw->hw_next;
 573                         here = *prev;
 574                 }
 575                 /* link in this qh, unless some earlier pass did that */
 576                 if (qh != here.qh) {
 577                         qh->qh_next = here;
 578                         if (here.qh)
 579                                 qh->hw->hw_next = *hw_p;
 580                         wmb();
 581                         prev->qh = qh;
 582                         *hw_p = QH_NEXT(ehci, qh->qh_dma);
 583                 }
 584         }
 585         qh->qh_state = QH_STATE_LINKED;
 586         qh->xacterrs = 0;
 587         qh->unlink_reason = 0;
 588
 589         /* update per-qh bandwidth for debugfs */
 590         ehci_to_hcd(ehci)->self.bandwidth_allocated += qh->ps.bw_period
 591                 ? ((qh->ps.usecs + qh->ps.c_usecs) / qh->ps.bw_period)
 592                 : (qh->ps.usecs * 8);
 593
 594         list_add(&qh->intr_node, &ehci->intr_qh_list);
 595
 596         /* maybe enable periodic schedule processing */
 597         ++ehci->intr_count;
 598         enable_periodic(ehci);
 599 }
 600
 601 static void qh_unlink_periodic(struct ehci_hcd *ehci, struct ehci_qh *qh)
 602 {
 603         unsigned        i;
 604         unsigned        period;
 605
 606         /*
 607          * If qh is for a low/full-speed device, simply unlinking it
 608          * could interfere with an ongoing split transaction.  To unlink
 609          * it safely would require setting the QH_INACTIVATE bit and
 610          * waiting at least one frame, as described in EHCI 4.12.2.5.
 611          *
 612          * We won't bother with any of this.  Instead, we assume that the
 613          * only reason for unlinking an interrupt QH while the current URB
 614          * is still active is to dequeue all the URBs (flush the whole
 615          * endpoint queue).
 616          *
 617          * If rebalancing the periodic schedule is ever implemented, this
 618          * approach will no longer be valid.
 619          */
 620
 621         /* high bandwidth, or otherwise part of every microframe */
 622         period = qh->ps.period ? : 1;
 623
 624         for (i = qh->ps.phase; i < ehci->periodic_size; i += period)
 625                 periodic_unlink(ehci, i, qh);
 626
 627         /* update per-qh bandwidth for debugfs */
 628         ehci_to_hcd(ehci)->self.bandwidth_allocated -= qh->ps.bw_period
 629                 ? ((qh->ps.usecs + qh->ps.c_usecs) / qh->ps.bw_period)
 630                 : (qh->ps.usecs * 8);
 631
 632         dev_dbg(&qh->ps.udev->dev,
 633                 "unlink qh%d-%04x/%p start %d [%d/%d us]\n",
 634                 qh->ps.period,
 635                 hc32_to_cpup(ehci, &qh->hw->hw_info2) & (QH_CMASK | QH_SMASK),
 636                 qh, qh->ps.phase, qh->ps.usecs, qh->ps.c_usecs);
 637
 638         /* qh->qh_next still "live" to HC */
 639         qh->qh_state = QH_STATE_UNLINK;
 640         qh->qh_next.ptr = NULL;
 641
 642         if (ehci->qh_scan_next == qh)
 643                 ehci->qh_scan_next = list_entry(qh->intr_node.next,
 644                                 struct ehci_qh, intr_node);
 645         list_del(&qh->intr_node);
 646 }
 647
 648 static void cancel_unlink_wait_intr(struct ehci_hcd *ehci, struct ehci_qh *qh)
 649 {
 650         if (qh->qh_state != QH_STATE_LINKED ||
 651                         list_empty(&qh->unlink_node))
 652                 return;
 653
 654         list_del_init(&qh->unlink_node);
 655
 656         /*
 657          * TODO: disable the event of EHCI_HRTIMER_START_UNLINK_INTR for
 658          * avoiding unnecessary CPU wakeup
 659          */
 660 }
 661
 662 static void start_unlink_intr(struct ehci_hcd *ehci, struct ehci_qh *qh)
 663 {
 664         /* If the QH isn't linked then there's nothing we can do. */
 665         if (qh->qh_state != QH_STATE_LINKED)
 666                 return;
 667
 668         /* if the qh is waiting for unlink, cancel it now */
 669         cancel_unlink_wait_intr(ehci, qh);
 670
 671         qh_unlink_periodic(ehci, qh);
 672
 673         /* Make sure the unlinks are visible before starting the timer */
 674         wmb();
 675
 676         /*
 677          * The EHCI spec doesn't say how long it takes the controller to
 678          * stop accessing an unlinked interrupt QH.  The timer delay is
 679          * 9 uframes; presumably that will be long enough.
 680          */
 681         qh->unlink_cycle = ehci->intr_unlink_cycle;
 682
 683         /* New entries go at the end of the intr_unlink list */
 684         list_add_tail(&qh->unlink_node, &ehci->intr_unlink);
 685
 686         if (ehci->intr_unlinking)
 687                 ;       /* Avoid recursive calls */
 688         else if (ehci->rh_state < EHCI_RH_RUNNING)
 689                 ehci_handle_intr_unlinks(ehci);
 690         else if (ehci->intr_unlink.next == &qh->unlink_node) {
 691                 ehci_enable_event(ehci, EHCI_HRTIMER_UNLINK_INTR, true);
 692                 ++ehci->intr_unlink_cycle;
 693         }
 694 }
 695
 696 /*
 697  * It is common only one intr URB is scheduled on one qh, and
 698  * given complete() is run in tasklet context, introduce a bit
 699  * delay to avoid unlink qh too early.
 700  */
 701 static void start_unlink_intr_wait(struct ehci_hcd *ehci,
 702                                    struct ehci_qh *qh)
 703 {
 704         qh->unlink_cycle = ehci->intr_unlink_wait_cycle;
 705
 706         /* New entries go at the end of the intr_unlink_wait list */
 707         list_add_tail(&qh->unlink_node, &ehci->intr_unlink_wait);
 708
 709         if (ehci->rh_state < EHCI_RH_RUNNING)
 710                 ehci_handle_start_intr_unlinks(ehci);
 711         else if (ehci->intr_unlink_wait.next == &qh->unlink_node) {
 712                 ehci_enable_event(ehci, EHCI_HRTIMER_START_UNLINK_INTR, true);
 713                 ++ehci->intr_unlink_wait_cycle;
 714         }
 715 }
 716
 717 static void end_unlink_intr(struct ehci_hcd *ehci, struct ehci_qh *qh)
 718 {
 719         struct ehci_qh_hw       *hw = qh->hw;
 720         int                     rc;
 721
 722         qh->qh_state = QH_STATE_IDLE;
 723         hw->hw_next = EHCI_LIST_END(ehci);
 724
 725         if (!list_empty(&qh->qtd_list))
 726                 qh_completions(ehci, qh);
 727
 728         /* reschedule QH iff another request is queued */
 729         if (!list_empty(&qh->qtd_list) && ehci->rh_state == EHCI_RH_RUNNING) {
 730                 rc = qh_schedule(ehci, qh);
 731                 if (rc == 0) {
 732                         qh_refresh(ehci, qh);
 733                         qh_link_periodic(ehci, qh);
 734                 }
 735
 736                 /* An error here likely indicates handshake failure
 737                  * or no space left in the schedule.  Neither fault
 738                  * should happen often ...
 739                  *
 740                  * FIXME kill the now-dysfunctional queued urbs
 741                  */
 742                 else {
 743                         ehci_err(ehci, "can't reschedule qh %p, err %d\n",
 744                                         qh, rc);
 745                 }
 746         }
 747
 748         /* maybe turn off periodic schedule */
 749         --ehci->intr_count;
 750         disable_periodic(ehci);
 751 }
 752
 753 /*-------------------------------------------------------------------------*/
 754
 755 static int check_period(
 756         struct ehci_hcd *ehci,
 757         unsigned        frame,
 758         unsigned        uframe,
 759         unsigned        uperiod,
 760         unsigned        usecs
 761 ) {
 762         /* complete split running into next frame?
 763          * given FSTN support, we could sometimes check...
 764          */
 765         if (uframe >= 8)
 766                 return 0;
 767
 768         /* convert "usecs we need" to "max already claimed" */
 769         usecs = ehci->uframe_periodic_max - usecs;
 770
 771         for (uframe += frame << 3; uframe < EHCI_BANDWIDTH_SIZE;
 772                         uframe += uperiod) {
 773                 if (ehci->bandwidth[uframe] > usecs)
 774                         return 0;
 775         }
 776
 777         /* success! */
 778         return 1;
 779 }
 780
 781 static int check_intr_schedule(
 782         struct ehci_hcd         *ehci,
 783         unsigned                frame,
 784         unsigned                uframe,
 785         struct ehci_qh          *qh,
 786         unsigned                *c_maskp,
 787         struct ehci_tt          *tt
 788 )
 789 {
 790         int             retval = -ENOSPC;
 791         u8              mask = 0;
 792
 793         if (qh->ps.c_usecs && uframe >= 6)      /* FSTN territory? */
 794                 goto done;
 795
 796         if (!check_period(ehci, frame, uframe, qh->ps.bw_uperiod, qh->ps.usecs))
 797                 goto done;
 798         if (!qh->ps.c_usecs) {
 799                 retval = 0;
 800                 *c_maskp = 0;
 801                 goto done;
 802         }
 803
 804 #ifdef CONFIG_USB_EHCI_TT_NEWSCHED
 805         if (tt_available(ehci, &qh->ps, tt, frame, uframe)) {
 806                 unsigned i;
 807
 808                 /* TODO : this may need FSTN for SSPLIT in uframe 5. */
 809                 for (i = uframe+2; i < 8 && i <= uframe+4; i++)
 810                         if (!check_period(ehci, frame, i,
 811                                         qh->ps.bw_uperiod, qh->ps.c_usecs))
 812                                 goto done;
 813                         else
 814                                 mask |= 1 << i;
 815
 816                 retval = 0;
 817
 818                 *c_maskp = mask;
 819         }
 820 #else
 821         /* Make sure this tt's buffer is also available for CSPLITs.
 822          * We pessimize a bit; probably the typical full speed case
 823          * doesn't need the second CSPLIT.
 824          *
 825          * NOTE:  both SPLIT and CSPLIT could be checked in just
 826          * one smart pass...
 827          */
 828         mask = 0x03 << (uframe + qh->gap_uf);
 829         *c_maskp = mask;
 830
 831         mask |= 1 << uframe;
 832         if (tt_no_collision(ehci, qh->ps.bw_period, qh->ps.udev, frame, mask)) {
 833                 if (!check_period(ehci, frame, uframe + qh->gap_uf + 1,
 834                                 qh->ps.bw_uperiod, qh->ps.c_usecs))
 835                         goto done;
 836                 if (!check_period(ehci, frame, uframe + qh->gap_uf,
 837                                 qh->ps.bw_uperiod, qh->ps.c_usecs))
 838                         goto done;
 839                 retval = 0;
 840         }
 841 #endif
 842 done:
 843         return retval;
 844 }
 845
 846 /* "first fit" scheduling policy used the first time through,
 847  * or when the previous schedule slot can't be re-used.
 848  */
 849 static int qh_schedule(struct ehci_hcd *ehci, struct ehci_qh *qh)
 850 {
 851         int             status = 0;
 852         unsigned        uframe;
 853         unsigned        c_mask;
 854         struct ehci_qh_hw       *hw = qh->hw;
 855         struct ehci_tt          *tt;
 856
 857         hw->hw_next = EHCI_LIST_END(ehci);
 858
 859         /* reuse the previous schedule slots, if we can */
 860         if (qh->ps.phase != NO_FRAME) {
 861                 ehci_dbg(ehci, "reused qh %p schedule\n", qh);
 862                 return 0;
 863         }
 864
 865         uframe = 0;
 866         c_mask = 0;
 867         tt = find_tt(qh->ps.udev);
 868         if (IS_ERR(tt)) {
 869                 status = PTR_ERR(tt);
 870                 goto done;
 871         }
 872         compute_tt_budget(ehci->tt_budget, tt);
 873
 874         /* else scan the schedule to find a group of slots such that all
 875          * uframes have enough periodic bandwidth available.
 876          */
 877         /* "normal" case, uframing flexible except with splits */
 878         if (qh->ps.bw_period) {
 879                 int             i;
 880                 unsigned        frame;
 881
 882                 for (i = qh->ps.bw_period; i > 0; --i) {
 883                         frame = ++ehci->random_frame & (qh->ps.bw_period - 1);
 884                         for (uframe = 0; uframe < 8; uframe++) {
 885                                 status = check_intr_schedule(ehci,
 886                                                 frame, uframe, qh, &c_mask, tt);
 887                                 if (status == 0)
 888                                         goto got_it;
 889                         }
 890                 }
 891
 892         /* qh->ps.bw_period == 0 means every uframe */
 893         } else {
 894                 status = check_intr_schedule(ehci, 0, 0, qh, &c_mask, tt);
 895         }
 896         if (status)
 897                 goto done;
 898
 899  got_it:
 900         qh->ps.phase = (qh->ps.period ? ehci->random_frame &
 901                         (qh->ps.period - 1) : 0);
 902         qh->ps.bw_phase = qh->ps.phase & (qh->ps.bw_period - 1);
 903         qh->ps.phase_uf = uframe;
 904         qh->ps.cs_mask = qh->ps.period ?
 905                         (c_mask << 8) | (1 << uframe) :
 906                         QH_SMASK;
 907
 908         /* reset S-frame and (maybe) C-frame masks */
 909         hw->hw_info2 &= cpu_to_hc32(ehci, ~(QH_CMASK | QH_SMASK));
 910         hw->hw_info2 |= cpu_to_hc32(ehci, qh->ps.cs_mask);
 911         reserve_release_intr_bandwidth(ehci, qh, 1);
 912
 913 done:
 914         return status;
 915 }
 916
 917 static int intr_submit(
 918         struct ehci_hcd         *ehci,
 919         struct urb              *urb,
 920         struct list_head        *qtd_list,
 921         gfp_t                   mem_flags
 922 ) {
 923         unsigned                epnum;
 924         unsigned long           flags;
 925         struct ehci_qh          *qh;
 926         int                     status;
 927         struct list_head        empty;
 928
 929         /* get endpoint and transfer/schedule data */
 930         epnum = urb->ep->desc.bEndpointAddress;
 931
 932         spin_lock_irqsave(&ehci->lock, flags);
 933
 934         if (unlikely(!HCD_HW_ACCESSIBLE(ehci_to_hcd(ehci)))) {
 935                 status = -ESHUTDOWN;
 936                 goto done_not_linked;
 937         }
 938         status = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
 939         if (unlikely(status))
 940                 goto done_not_linked;
 941
 942         /* get qh and force any scheduling errors */
 943         INIT_LIST_HEAD(&empty);
 944         qh = qh_append_tds(ehci, urb, &empty, epnum, &urb->ep->hcpriv);
 945         if (qh == NULL) {
 946                 status = -ENOMEM;
 947                 goto done;
 948         }
 949         if (qh->qh_state == QH_STATE_IDLE) {
 950                 status = qh_schedule(ehci, qh);
 951                 if (status)
 952                         goto done;
 953         }
 954
 955         /* then queue the urb's tds to the qh */
 956         qh = qh_append_tds(ehci, urb, qtd_list, epnum, &urb->ep->hcpriv);
 957         BUG_ON(qh == NULL);
 958
 959         /* stuff into the periodic schedule */
 960         if (qh->qh_state == QH_STATE_IDLE) {
 961                 qh_refresh(ehci, qh);
 962                 qh_link_periodic(ehci, qh);
 963         } else {
 964                 /* cancel unlink wait for the qh */
 965                 cancel_unlink_wait_intr(ehci, qh);
 966         }
 967
 968         /* ... update usbfs periodic stats */
 969         ehci_to_hcd(ehci)->self.bandwidth_int_reqs++;
 970
 971 done:
 972         if (unlikely(status))
 973                 usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
 974 done_not_linked:
 975         spin_unlock_irqrestore(&ehci->lock, flags);
 976         if (status)
 977                 qtd_list_free(ehci, urb, qtd_list);
 978
 979         return status;
 980 }
 981
 982 static void scan_intr(struct ehci_hcd *ehci)
 983 {
 984         struct ehci_qh          *qh;
 985
 986         list_for_each_entry_safe(qh, ehci->qh_scan_next, &ehci->intr_qh_list,
 987                         intr_node) {
 988
 989                 /* clean any finished work for this qh */
 990                 if (!list_empty(&qh->qtd_list)) {
 991                         int temp;
 992
 993                         /*
 994                          * Unlinks could happen here; completion reporting
 995                          * drops the lock.  That's why ehci->qh_scan_next
 996                          * always holds the next qh to scan; if the next qh
 997                          * gets unlinked then ehci->qh_scan_next is adjusted
 998                          * in qh_unlink_periodic().
 999                          */
1000                         temp = qh_completions(ehci, qh);
1001                         if (unlikely(temp))
1002                                 start_unlink_intr(ehci, qh);
1003                         else if (unlikely(list_empty(&qh->qtd_list) &&
1004                                         qh->qh_state == QH_STATE_LINKED))
1005                                 start_unlink_intr_wait(ehci, qh);
1006                 }
1007         }
1008 }
1009
1010 /*-------------------------------------------------------------------------*/
1011
1012 /* ehci_iso_stream ops work with both ITD and SITD */
1013
1014 static struct ehci_iso_stream *
1015 iso_stream_alloc(gfp_t mem_flags)
1016 {
1017         struct ehci_iso_stream *stream;
1018
1019         stream = kzalloc(sizeof(*stream), mem_flags);
1020         if (likely(stream != NULL)) {
1021                 INIT_LIST_HEAD(&stream->td_list);
1022                 INIT_LIST_HEAD(&stream->free_list);
1023                 stream->next_uframe = NO_FRAME;
1024                 stream->ps.phase = NO_FRAME;
1025         }
1026         return stream;
1027 }
1028
1029 static void
1030 iso_stream_init(
1031         struct ehci_hcd         *ehci,
1032         struct ehci_iso_stream  *stream,
1033         struct urb              *urb
1034 )
1035 {
1036         static const u8 smask_out[] = { 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f };
1037
1038         struct usb_device       *dev = urb->dev;
1039         u32                     buf1;
1040         unsigned                epnum, maxp;
1041         int                     is_input;
1042         unsigned                tmp;
1043
1044         /*
1045          * this might be a "high bandwidth" highspeed endpoint,
1046          * as encoded in the ep descriptor's wMaxPacket field
1047          */
1048         epnum = usb_pipeendpoint(urb->pipe);
1049         is_input = usb_pipein(urb->pipe) ? USB_DIR_IN : 0;
1050         maxp = usb_endpoint_maxp(&urb->ep->desc);
1051         buf1 = is_input ? 1 << 11 : 0;
1052
1053         /* knows about ITD vs SITD */
1054         if (dev->speed == USB_SPEED_HIGH) {
1055                 unsigned multi = usb_endpoint_maxp_mult(&urb->ep->desc);
1056
1057                 stream->highspeed = 1;
1058
1059                 buf1 |= maxp;
1060                 maxp *= multi;
1061
1062                 stream->buf0 = cpu_to_hc32(ehci, (epnum << 8) | dev->devnum);
1063                 stream->buf1 = cpu_to_hc32(ehci, buf1);
1064                 stream->buf2 = cpu_to_hc32(ehci, multi);
1065
1066                 /* usbfs wants to report the average usecs per frame tied up
1067                  * when transfers on this endpoint are scheduled ...
1068                  */
1069                 stream->ps.usecs = HS_USECS_ISO(maxp);
1070
1071                 /* period for bandwidth allocation */
1072                 tmp = min_t(unsigned, EHCI_BANDWIDTH_SIZE,
1073                                 1 << (urb->ep->desc.bInterval - 1));
1074
1075                 /* Allow urb->interval to override */
1076                 stream->ps.bw_uperiod = min_t(unsigned, tmp, urb->interval);
1077
1078                 stream->uperiod = urb->interval;
1079                 stream->ps.period = urb->interval >> 3;
1080                 stream->bandwidth = stream->ps.usecs * 8 /
1081                                 stream->ps.bw_uperiod;
1082
1083         } else {
1084                 u32             addr;
1085                 int             think_time;
1086                 int             hs_transfers;
1087
1088                 addr = dev->ttport << 24;
1089                 if (!ehci_is_TDI(ehci)
1090                                 || (dev->tt->hub !=
1091                                         ehci_to_hcd(ehci)->self.root_hub))
1092                         addr |= dev->tt->hub->devnum << 16;
1093                 addr |= epnum << 8;
1094                 addr |= dev->devnum;
1095                 stream->ps.usecs = HS_USECS_ISO(maxp);
1096                 think_time = dev->tt->think_time;
1097                 stream->ps.tt_usecs = NS_TO_US(think_time + usb_calc_bus_time(
1098                                 dev->speed, is_input, 1, maxp));
1099                 hs_transfers = max(1u, (maxp + 187) / 188);
1100                 if (is_input) {
1101                         u32     tmp;
1102
1103                         addr |= 1 << 31;
1104                         stream->ps.c_usecs = stream->ps.usecs;
1105                         stream->ps.usecs = HS_USECS_ISO(1);
1106                         stream->ps.cs_mask = 1;
1107
1108                         /* c-mask as specified in USB 2.0 11.18.4 3.c */
1109                         tmp = (1 << (hs_transfers + 2)) - 1;
1110                         stream->ps.cs_mask |= tmp << (8 + 2);
1111                 } else
1112                         stream->ps.cs_mask = smask_out[hs_transfers - 1];
1113
1114                 /* period for bandwidth allocation */
1115                 tmp = min_t(unsigned, EHCI_BANDWIDTH_FRAMES,
1116                                 1 << (urb->ep->desc.bInterval - 1));
1117
1118                 /* Allow urb->interval to override */
1119                 stream->ps.bw_period = min_t(unsigned, tmp, urb->interval);
1120                 stream->ps.bw_uperiod = stream->ps.bw_period << 3;
1121
1122                 stream->ps.period = urb->interval;
1123                 stream->uperiod = urb->interval << 3;
1124                 stream->bandwidth = (stream->ps.usecs + stream->ps.c_usecs) /
1125                                 stream->ps.bw_period;
1126
1127                 /* stream->splits gets created from cs_mask later */
1128                 stream->address = cpu_to_hc32(ehci, addr);
1129         }
1130
1131         stream->ps.udev = dev;
1132         stream->ps.ep = urb->ep;
1133
1134         stream->bEndpointAddress = is_input | epnum;
1135         stream->maxp = maxp;
1136 }
1137
1138 static struct ehci_iso_stream *
1139 iso_stream_find(struct ehci_hcd *ehci, struct urb *urb)
1140 {
1141         unsigned                epnum;
1142         struct ehci_iso_stream  *stream;
1143         struct usb_host_endpoint *ep;
1144         unsigned long           flags;
1145
1146         epnum = usb_pipeendpoint (urb->pipe);
1147         if (usb_pipein(urb->pipe))
1148                 ep = urb->dev->ep_in[epnum];
1149         else
1150                 ep = urb->dev->ep_out[epnum];
1151
1152         spin_lock_irqsave(&ehci->lock, flags);
1153         stream = ep->hcpriv;
1154
1155         if (unlikely(stream == NULL)) {
1156                 stream = iso_stream_alloc(GFP_ATOMIC);
1157                 if (likely(stream != NULL)) {
1158                         ep->hcpriv = stream;
1159                         iso_stream_init(ehci, stream, urb);
1160                 }
1161
1162         /* if dev->ep [epnum] is a QH, hw is set */
1163         } else if (unlikely(stream->hw != NULL)) {
1164                 ehci_dbg(ehci, "dev %s ep%d%s, not iso??\n",
1165                         urb->dev->devpath, epnum,
1166                         usb_pipein(urb->pipe) ? "in" : "out");
1167                 stream = NULL;
1168         }
1169
1170         spin_unlock_irqrestore(&ehci->lock, flags);
1171         return stream;
1172 }
1173
1174 /*-------------------------------------------------------------------------*/
1175
1176 /* ehci_iso_sched ops can be ITD-only or SITD-only */
1177
1178 static struct ehci_iso_sched *
1179 iso_sched_alloc(unsigned packets, gfp_t mem_flags)
1180 {
1181         struct ehci_iso_sched   *iso_sched;
1182         int                     size = sizeof(*iso_sched);
1183
1184         size += packets * sizeof(struct ehci_iso_packet);
1185         iso_sched = kzalloc(size, mem_flags);
1186         if (likely(iso_sched != NULL))
1187                 INIT_LIST_HEAD(&iso_sched->td_list);
1188
1189         return iso_sched;
1190 }
1191
1192 static inline void
1193 itd_sched_init(
1194         struct ehci_hcd         *ehci,
1195         struct ehci_iso_sched   *iso_sched,
1196         struct ehci_iso_stream  *stream,
1197         struct urb              *urb
1198 )
1199 {
1200         unsigned        i;
1201         dma_addr_t      dma = urb->transfer_dma;
1202
1203         /* how many uframes are needed for these transfers */
1204         iso_sched->span = urb->number_of_packets * stream->uperiod;
1205
1206         /* figure out per-uframe itd fields that we'll need later
1207          * when we fit new itds into the schedule.
1208          */
1209         for (i = 0; i < urb->number_of_packets; i++) {
1210                 struct ehci_iso_packet  *uframe = &iso_sched->packet[i];
1211                 unsigned                length;
1212                 dma_addr_t              buf;
1213                 u32                     trans;
1214
1215                 length = urb->iso_frame_desc[i].length;
1216                 buf = dma + urb->iso_frame_desc[i].offset;
1217
1218                 trans = EHCI_ISOC_ACTIVE;
1219                 trans |= buf & 0x0fff;
1220                 if (unlikely(((i + 1) == urb->number_of_packets))
1221                                 && !(urb->transfer_flags & URB_NO_INTERRUPT))
1222                         trans |= EHCI_ITD_IOC;
1223                 trans |= length << 16;
1224                 uframe->transaction = cpu_to_hc32(ehci, trans);
1225
1226                 /* might need to cross a buffer page within a uframe */
1227                 uframe->bufp = (buf & ~(u64)0x0fff);
1228                 buf += length;
1229                 if (unlikely((uframe->bufp != (buf & ~(u64)0x0fff))))
1230                         uframe->cross = 1;
1231         }
1232 }
1233
1234 static void
1235 iso_sched_free(
1236         struct ehci_iso_stream  *stream,
1237         struct ehci_iso_sched   *iso_sched
1238 )
1239 {
1240         if (!iso_sched)
1241                 return;
1242         /* caller must hold ehci->lock! */
1243         list_splice(&iso_sched->td_list, &stream->free_list);
1244         kfree(iso_sched);
1245 }
1246
1247 static int
1248 itd_urb_transaction(
1249         struct ehci_iso_stream  *stream,
1250         struct ehci_hcd         *ehci,
1251         struct urb              *urb,
1252         gfp_t                   mem_flags
1253 )
1254 {
1255         struct ehci_itd         *itd;
1256         dma_addr_t              itd_dma;
1257         int                     i;
1258         unsigned                num_itds;
1259         struct ehci_iso_sched   *sched;
1260         unsigned long           flags;
1261
1262         sched = iso_sched_alloc(urb->number_of_packets, mem_flags);
1263         if (unlikely(sched == NULL))
1264                 return -ENOMEM;
1265
1266         itd_sched_init(ehci, sched, stream, urb);
1267
1268         if (urb->interval < 8)
1269                 num_itds = 1 + (sched->span + 7) / 8;
1270         else
1271                 num_itds = urb->number_of_packets;
1272
1273         /* allocate/init ITDs */
1274         spin_lock_irqsave(&ehci->lock, flags);
1275         for (i = 0; i < num_itds; i++) {
1276
1277                 /*
1278                  * Use iTDs from the free list, but not iTDs that may
1279                  * still be in use by the hardware.
1280                  */
1281                 if (likely(!list_empty(&stream->free_list))) {
1282                         itd = list_first_entry(&stream->free_list,
1283                                         struct ehci_itd, itd_list);
1284                         if (itd->frame == ehci->now_frame)
1285                                 goto alloc_itd;
1286                         list_del(&itd->itd_list);
1287                         itd_dma = itd->itd_dma;
1288                 } else {
1289  alloc_itd:
1290                         spin_unlock_irqrestore(&ehci->lock, flags);
1291                         itd = dma_pool_alloc(ehci->itd_pool, mem_flags,
1292                                         &itd_dma);
1293                         spin_lock_irqsave(&ehci->lock, flags);
1294                         if (!itd) {
1295                                 iso_sched_free(stream, sched);
1296                                 spin_unlock_irqrestore(&ehci->lock, flags);
1297                                 return -ENOMEM;
1298                         }
1299                 }
1300
1301                 memset(itd, 0, sizeof(*itd));
1302                 itd->itd_dma = itd_dma;
1303                 itd->frame = NO_FRAME;
1304                 list_add(&itd->itd_list, &sched->td_list);
1305         }
1306         spin_unlock_irqrestore(&ehci->lock, flags);
1307
1308         /* temporarily store schedule info in hcpriv */
1309         urb->hcpriv = sched;
1310         urb->error_count = 0;
1311         return 0;
1312 }
1313
1314 /*-------------------------------------------------------------------------*/
1315
1316 static void reserve_release_iso_bandwidth(struct ehci_hcd *ehci,
1317                 struct ehci_iso_stream *stream, int sign)
1318 {
1319         unsigned                uframe;
1320         unsigned                i, j;
1321         unsigned                s_mask, c_mask, m;
1322         int                     usecs = stream->ps.usecs;
1323         int                     c_usecs = stream->ps.c_usecs;
1324         int                     tt_usecs = stream->ps.tt_usecs;
1325         struct ehci_tt          *tt;
1326
1327         if (stream->ps.phase == NO_FRAME)       /* Bandwidth wasn't reserved */
1328                 return;
1329         uframe = stream->ps.bw_phase << 3;
1330
1331         bandwidth_dbg(ehci, sign, "iso", &stream->ps);
1332
1333         if (sign < 0) {         /* Release bandwidth */
1334                 usecs = -usecs;
1335                 c_usecs = -c_usecs;
1336                 tt_usecs = -tt_usecs;
1337         }
1338
1339         if (!stream->splits) {          /* High speed */
1340                 for (i = uframe + stream->ps.phase_uf; i < EHCI_BANDWIDTH_SIZE;
1341                                 i += stream->ps.bw_uperiod)
1342                         ehci->bandwidth[i] += usecs;
1343
1344         } else {                        /* Full speed */
1345                 s_mask = stream->ps.cs_mask;
1346                 c_mask = s_mask >> 8;
1347
1348                 /* NOTE: adjustment needed for frame overflow */
1349                 for (i = uframe; i < EHCI_BANDWIDTH_SIZE;
1350                                 i += stream->ps.bw_uperiod) {
1351                         for ((j = stream->ps.phase_uf, m = 1 << j); j < 8;
1352                                         (++j, m <<= 1)) {
1353                                 if (s_mask & m)
1354                                         ehci->bandwidth[i+j] += usecs;
1355                                 else if (c_mask & m)
1356                                         ehci->bandwidth[i+j] += c_usecs;
1357                         }
1358                 }
1359
1360                 tt = find_tt(stream->ps.udev);
1361                 if (sign > 0)
1362                         list_add_tail(&stream->ps.ps_list, &tt->ps_list);
1363                 else
1364                         list_del(&stream->ps.ps_list);
1365
1366                 for (i = uframe >> 3; i < EHCI_BANDWIDTH_FRAMES;
1367                                 i += stream->ps.bw_period)
1368                         tt->bandwidth[i] += tt_usecs;
1369         }
1370 }
1371
1372 static inline int
1373 itd_slot_ok(
1374         struct ehci_hcd         *ehci,
1375         struct ehci_iso_stream  *stream,
1376         unsigned                uframe
1377 )
1378 {
1379         unsigned                usecs;
1380
1381         /* convert "usecs we need" to "max already claimed" */
1382         usecs = ehci->uframe_periodic_max - stream->ps.usecs;
1383
1384         for (uframe &= stream->ps.bw_uperiod - 1; uframe < EHCI_BANDWIDTH_SIZE;
1385                         uframe += stream->ps.bw_uperiod) {
1386                 if (ehci->bandwidth[uframe] > usecs)
1387                         return 0;
1388         }
1389         return 1;
1390 }
1391
1392 static inline int
1393 sitd_slot_ok(
1394         struct ehci_hcd         *ehci,
1395         struct ehci_iso_stream  *stream,
1396         unsigned                uframe,
1397         struct ehci_iso_sched   *sched,
1398         struct ehci_tt          *tt
1399 )
1400 {
1401         unsigned                mask, tmp;
1402         unsigned                frame, uf;
1403
1404         mask = stream->ps.cs_mask << (uframe & 7);
1405
1406         /* for OUT, don't wrap SSPLIT into H-microframe 7 */
1407         if (((stream->ps.cs_mask & 0xff) << (uframe & 7)) >= (1 << 7))
1408                 return 0;
1409
1410         /* for IN, don't wrap CSPLIT into the next frame */
1411         if (mask & ~0xffff)
1412                 return 0;
1413
1414         /* check bandwidth */
1415         uframe &= stream->ps.bw_uperiod - 1;
1416         frame = uframe >> 3;
1417
1418 #ifdef CONFIG_USB_EHCI_TT_NEWSCHED
1419         /* The tt's fullspeed bus bandwidth must be available.
1420          * tt_available scheduling guarantees 10+% for control/bulk.
1421          */
1422         uf = uframe & 7;
1423         if (!tt_available(ehci, &stream->ps, tt, frame, uf))
1424                 return 0;
1425 #else
1426         /* tt must be idle for start(s), any gap, and csplit.
1427          * assume scheduling slop leaves 10+% for control/bulk.
1428          */
1429         if (!tt_no_collision(ehci, stream->ps.bw_period,
1430                         stream->ps.udev, frame, mask))
1431                 return 0;
1432 #endif
1433
1434         do {
1435                 unsigned        max_used;
1436                 unsigned        i;
1437
1438                 /* check starts (OUT uses more than one) */
1439                 uf = uframe;
1440                 max_used = ehci->uframe_periodic_max - stream->ps.usecs;
1441                 for (tmp = stream->ps.cs_mask & 0xff; tmp; tmp >>= 1, uf++) {
1442                         if (ehci->bandwidth[uf] > max_used)
1443                                 return 0;
1444                 }
1445
1446                 /* for IN, check CSPLIT */
1447                 if (stream->ps.c_usecs) {
1448                         max_used = ehci->uframe_periodic_max -
1449                                         stream->ps.c_usecs;
1450                         uf = uframe & ~7;
1451                         tmp = 1 << (2+8);
1452                         for (i = (uframe & 7) + 2; i < 8; (++i, tmp <<= 1)) {
1453                                 if ((stream->ps.cs_mask & tmp) == 0)
1454                                         continue;
1455                                 if (ehci->bandwidth[uf+i] > max_used)
1456                                         return 0;
1457                         }
1458                 }
1459
1460                 uframe += stream->ps.bw_uperiod;
1461         } while (uframe < EHCI_BANDWIDTH_SIZE);
1462
1463         stream->ps.cs_mask <<= uframe & 7;
1464         stream->splits = cpu_to_hc32(ehci, stream->ps.cs_mask);
1465         return 1;
1466 }
1467
1468 /*
1469  * This scheduler plans almost as far into the future as it has actual
1470  * periodic schedule slots.  (Affected by TUNE_FLS, which defaults to
1471  * "as small as possible" to be cache-friendlier.)  That limits the size
1472  * transfers you can stream reliably; avoid more than 64 msec per urb.
1473  * Also avoid queue depths of less than ehci's worst irq latency (affected
1474  * by the per-urb URB_NO_INTERRUPT hint, the log2_irq_thresh module parameter,
1475  * and other factors); or more than about 230 msec total (for portability,
1476  * given EHCI_TUNE_FLS and the slop).  Or, write a smarter scheduler!
1477  */
1478
1479 static int
1480 iso_stream_schedule(
1481         struct ehci_hcd         *ehci,
1482         struct urb              *urb,
1483         struct ehci_iso_stream  *stream
1484 )
1485 {
1486         u32                     now, base, next, start, period, span, now2;
1487         u32                     wrap = 0, skip = 0;
1488         int                     status = 0;
1489         unsigned                mod = ehci->periodic_size << 3;
1490         struct ehci_iso_sched   *sched = urb->hcpriv;
1491         bool                    empty = list_empty(&stream->td_list);
1492         bool                    new_stream = false;
1493
1494         period = stream->uperiod;
1495         span = sched->span;
1496         if (!stream->highspeed)
1497                 span <<= 3;
1498
1499         /* Start a new isochronous stream? */
1500         if (unlikely(empty && !hcd_periodic_completion_in_progress(
1501                         ehci_to_hcd(ehci), urb->ep))) {
1502
1503                 /* Schedule the endpoint */
1504                 if (stream->ps.phase == NO_FRAME) {
1505                         int             done = 0;
1506                         struct ehci_tt  *tt = find_tt(stream->ps.udev);
1507
1508                         if (IS_ERR(tt)) {
1509                                 status = PTR_ERR(tt);
1510                                 goto fail;
1511                         }
1512                         compute_tt_budget(ehci->tt_budget, tt);
1513
1514                         start = ((-(++ehci->random_frame)) << 3) & (period - 1);
1515
1516                         /* find a uframe slot with enough bandwidth.
1517                          * Early uframes are more precious because full-speed
1518                          * iso IN transfers can't use late uframes,
1519                          * and therefore they should be allocated last.
1520                          */
1521                         next = start;
1522                         start += period;
1523                         do {
1524                                 start--;
1525                                 /* check schedule: enough space? */
1526                                 if (stream->highspeed) {
1527                                         if (itd_slot_ok(ehci, stream, start))
1528                                                 done = 1;
1529                                 } else {
1530                                         if ((start % 8) >= 6)
1531                                                 continue;
1532                                         if (sitd_slot_ok(ehci, stream, start,
1533                                                         sched, tt))
1534                                                 done = 1;
1535                                 }
1536                         } while (start > next && !done);
1537
1538                         /* no room in the schedule */
1539                         if (!done) {
1540                                 ehci_dbg(ehci, "iso sched full %p", urb);
1541                                 status = -ENOSPC;
1542                                 goto fail;
1543                         }
1544                         stream->ps.phase = (start >> 3) &
1545                                         (stream->ps.period - 1);
1546                         stream->ps.bw_phase = stream->ps.phase &
1547                                         (stream->ps.bw_period - 1);
1548                         stream->ps.phase_uf = start & 7;
1549                         reserve_release_iso_bandwidth(ehci, stream, 1);
1550                 }
1551
1552                 /* New stream is already scheduled; use the upcoming slot */
1553                 else {
1554                         start = (stream->ps.phase << 3) + stream->ps.phase_uf;
1555                 }
1556
1557                 stream->next_uframe = start;
1558                 new_stream = true;
1559         }
1560
1561         now = ehci_read_frame_index(ehci) & (mod - 1);
1562
1563         /* Take the isochronous scheduling threshold into account */
1564         if (ehci->i_thresh)
1565                 next = now + ehci->i_thresh;    /* uframe cache */
1566         else
1567                 next = (now + 2 + 7) & ~0x07;   /* full frame cache */
1568
1569         /* If needed, initialize last_iso_frame so that this URB will be seen */
1570         if (ehci->isoc_count == 0)
1571                 ehci->last_iso_frame = now >> 3;
1572
1573         /*
1574          * Use ehci->last_iso_frame as the base.  There can't be any
1575          * TDs scheduled for earlier than that.
1576          */
1577         base = ehci->last_iso_frame << 3;
1578         next = (next - base) & (mod - 1);
1579         start = (stream->next_uframe - base) & (mod - 1);
1580
1581         if (unlikely(new_stream))
1582                 goto do_ASAP;
1583
1584         /*
1585          * Typical case: reuse current schedule, stream may still be active.
1586          * Hopefully there are no gaps from the host falling behind
1587          * (irq delays etc).  If there are, the behavior depends on
1588          * whether URB_ISO_ASAP is set.
1589          */
1590         now2 = (now - base) & (mod - 1);
1591
1592         /* Is the schedule about to wrap around? */
1593         if (unlikely(!empty && start < period)) {
1594                 ehci_dbg(ehci, "request %p would overflow (%u-%u < %u mod %u)\n",
1595                                 urb, stream->next_uframe, base, period, mod);
1596                 status = -EFBIG;
1597                 goto fail;
1598         }
1599
1600         /* Is the next packet scheduled after the base time? */
1601         if (likely(!empty || start <= now2 + period)) {
1602
1603                 /* URB_ISO_ASAP: make sure that start >= next */
1604                 if (unlikely(start < next &&
1605                                 (urb->transfer_flags & URB_ISO_ASAP)))
1606                         goto do_ASAP;
1607
1608                 /* Otherwise use start, if it's not in the past */
1609                 if (likely(start >= now2))
1610                         goto use_start;
1611
1612         /* Otherwise we got an underrun while the queue was empty */
1613         } else {
1614                 if (urb->transfer_flags & URB_ISO_ASAP)
1615                         goto do_ASAP;
1616                 wrap = mod;
1617                 now2 += mod;
1618         }
1619
1620         /* How many uframes and packets do we need to skip? */
1621         skip = (now2 - start + period - 1) & -period;
1622         if (skip >= span) {             /* Entirely in the past? */
1623                 ehci_dbg(ehci, "iso underrun %p (%u+%u < %u) [%u]\n",
1624                                 urb, start + base, span - period, now2 + base,
1625                                 base);
1626
1627                 /* Try to keep the last TD intact for scanning later */
1628                 skip = span - period;
1629
1630                 /* Will it come before the current scan position? */
1631                 if (empty) {
1632                         skip = span;    /* Skip the entire URB */
1633                         status = 1;     /* and give it back immediately */
1634                         iso_sched_free(stream, sched);
1635                         sched = NULL;
1636                 }
1637         }
1638         urb->error_count = skip / period;
1639         if (sched)
1640                 sched->first_packet = urb->error_count;
1641         goto use_start;
1642
1643  do_ASAP:
1644         /* Use the first slot after "next" */
1645         start = next + ((start - next) & (period - 1));
1646
1647  use_start:
1648         /* Tried to schedule too far into the future? */
1649         if (unlikely(start + span - period >= mod + wrap)) {
1650                 ehci_dbg(ehci, "request %p would overflow (%u+%u >= %u)\n",
1651                                 urb, start, span - period, mod + wrap);
1652                 status = -EFBIG;
1653                 goto fail;
1654         }
1655
1656         start += base;
1657         stream->next_uframe = (start + skip) & (mod - 1);
1658
1659         /* report high speed start in uframes; full speed, in frames */
1660         urb->start_frame = start & (mod - 1);
1661         if (!stream->highspeed)
1662                 urb->start_frame >>= 3;
1663         return status;
1664
1665  fail:
1666         iso_sched_free(stream, sched);
1667         urb->hcpriv = NULL;
1668         return status;
1669 }
1670
1671 /*-------------------------------------------------------------------------*/
1672
1673 static inline void
1674 itd_init(struct ehci_hcd *ehci, struct ehci_iso_stream *stream,
1675                 struct ehci_itd *itd)
1676 {
1677         int i;
1678
1679         /* it's been recently zeroed */
1680         itd->hw_next = EHCI_LIST_END(ehci);
1681         itd->hw_bufp[0] = stream->buf0;
1682         itd->hw_bufp[1] = stream->buf1;
1683         itd->hw_bufp[2] = stream->buf2;
1684
1685         for (i = 0; i < 8; i++)
1686                 itd->index[i] = -1;
1687
1688         /* All other fields are filled when scheduling */
1689 }
1690
1691 static inline void
1692 itd_patch(
1693         struct ehci_hcd         *ehci,
1694         struct ehci_itd         *itd,
1695         struct ehci_iso_sched   *iso_sched,
1696         unsigned                index,
1697         u16                     uframe
1698 )
1699 {
1700         struct ehci_iso_packet  *uf = &iso_sched->packet[index];
1701         unsigned                pg = itd->pg;
1702
1703         /* BUG_ON(pg == 6 && uf->cross); */
1704
1705         uframe &= 0x07;
1706         itd->index[uframe] = index;
1707
1708         itd->hw_transaction[uframe] = uf->transaction;
1709         itd->hw_transaction[uframe] |= cpu_to_hc32(ehci, pg << 12);
1710         itd->hw_bufp[pg] |= cpu_to_hc32(ehci, uf->bufp & ~(u32)0);
1711         itd->hw_bufp_hi[pg] |= cpu_to_hc32(ehci, (u32)(uf->bufp >> 32));
1712
1713         /* iso_frame_desc[].offset must be strictly increasing */
1714         if (unlikely(uf->cross)) {
1715                 u64     bufp = uf->bufp + 4096;
1716
1717                 itd->pg = ++pg;
1718                 itd->hw_bufp[pg] |= cpu_to_hc32(ehci, bufp & ~(u32)0);
1719                 itd->hw_bufp_hi[pg] |= cpu_to_hc32(ehci, (u32)(bufp >> 32));
1720         }
1721 }
1722
1723 static inline void
1724 itd_link(struct ehci_hcd *ehci, unsigned frame, struct ehci_itd *itd)
1725 {
1726         union ehci_shadow       *prev = &ehci->pshadow[frame];
1727         __hc32                  *hw_p = &ehci->periodic[frame];
1728         union ehci_shadow       here = *prev;
1729         __hc32                  type = 0;
1730
1731         /* skip any iso nodes which might belong to previous microframes */
1732         while (here.ptr) {
1733                 type = Q_NEXT_TYPE(ehci, *hw_p);
1734                 if (type == cpu_to_hc32(ehci, Q_TYPE_QH))
1735                         break;
1736                 prev = periodic_next_shadow(ehci, prev, type);
1737                 hw_p = shadow_next_periodic(ehci, &here, type);
1738                 here = *prev;
1739         }
1740
1741         itd->itd_next = here;
1742         itd->hw_next = *hw_p;
1743         prev->itd = itd;
1744         itd->frame = frame;
1745         wmb();
1746         *hw_p = cpu_to_hc32(ehci, itd->itd_dma | Q_TYPE_ITD);
1747 }
1748
1749 /* fit urb's itds into the selected schedule slot; activate as needed */
1750 static void itd_link_urb(
1751         struct ehci_hcd         *ehci,
1752         struct urb              *urb,
1753         unsigned                mod,
1754         struct ehci_iso_stream  *stream
1755 )
1756 {
1757         int                     packet;
1758         unsigned                next_uframe, uframe, frame;
1759         struct ehci_iso_sched   *iso_sched = urb->hcpriv;
1760         struct ehci_itd         *itd;
1761
1762         next_uframe = stream->next_uframe & (mod - 1);
1763
1764         if (unlikely(list_empty(&stream->td_list)))
1765                 ehci_to_hcd(ehci)->self.bandwidth_allocated
1766                                 += stream->bandwidth;
1767
1768         if (ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs == 0) {
1769                 if (ehci->amd_pll_fix == 1)
1770                         usb_amd_quirk_pll_disable();
1771         }
1772
1773         ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs++;
1774
1775         /* fill iTDs uframe by uframe */
1776         for (packet = iso_sched->first_packet, itd = NULL;
1777                         packet < urb->number_of_packets;) {
1778                 if (itd == NULL) {
1779                         /* ASSERT:  we have all necessary itds */
1780                         /* BUG_ON(list_empty(&iso_sched->td_list)); */
1781
1782                         /* ASSERT:  no itds for this endpoint in this uframe */
1783
1784                         itd = list_entry(iso_sched->td_list.next,
1785                                         struct ehci_itd, itd_list);
1786                         list_move_tail(&itd->itd_list, &stream->td_list);
1787                         itd->stream = stream;
1788                         itd->urb = urb;
1789                         itd_init(ehci, stream, itd);
1790                 }
1791
1792                 uframe = next_uframe & 0x07;
1793                 frame = next_uframe >> 3;
1794
1795                 itd_patch(ehci, itd, iso_sched, packet, uframe);
1796
1797                 next_uframe += stream->uperiod;
1798                 next_uframe &= mod - 1;
1799                 packet++;
1800
1801                 /* link completed itds into the schedule */
1802                 if (((next_uframe >> 3) != frame)
1803                                 || packet == urb->number_of_packets) {
1804                         itd_link(ehci, frame & (ehci->periodic_size - 1), itd);
1805                         itd = NULL;
1806                 }
1807         }
1808         stream->next_uframe = next_uframe;
1809
1810         /* don't need that schedule data any more */
1811         iso_sched_free(stream, iso_sched);
1812         urb->hcpriv = stream;
1813
1814         ++ehci->isoc_count;
1815         enable_periodic(ehci);
1816 }
1817
1818 #define ISO_ERRS (EHCI_ISOC_BUF_ERR | EHCI_ISOC_BABBLE | EHCI_ISOC_XACTERR)
1819
1820 /* Process and recycle a completed ITD.  Return true iff its urb completed,
1821  * and hence its completion callback probably added things to the hardware
1822  * schedule.
1823  *
1824  * Note that we carefully avoid recycling this descriptor until after any
1825  * completion callback runs, so that it won't be reused quickly.  That is,
1826  * assuming (a) no more than two urbs per frame on this endpoint, and also
1827  * (b) only this endpoint's completions submit URBs.  It seems some silicon
1828  * corrupts things if you reuse completed descriptors very quickly...
1829  */
1830 static bool itd_complete(struct ehci_hcd *ehci, struct ehci_itd *itd)
1831 {
1832         struct urb                              *urb = itd->urb;
1833         struct usb_iso_packet_descriptor        *desc;
1834         u32                                     t;
1835         unsigned                                uframe;
1836         int                                     urb_index = -1;
1837         struct ehci_iso_stream                  *stream = itd->stream;
1838         bool                                    retval = false;
1839
1840         /* for each uframe with a packet */
1841         for (uframe = 0; uframe < 8; uframe++) {
1842                 if (likely(itd->index[uframe] == -1))
1843                         continue;
1844                 urb_index = itd->index[uframe];
1845                 desc = &urb->iso_frame_desc[urb_index];
1846
1847                 t = hc32_to_cpup(ehci, &itd->hw_transaction[uframe]);
1848                 itd->hw_transaction[uframe] = 0;
1849
1850                 /* report transfer status */
1851                 if (unlikely(t & ISO_ERRS)) {
1852                         urb->error_count++;
1853                         if (t & EHCI_ISOC_BUF_ERR)
1854                                 desc->status = usb_pipein(urb->pipe)
1855                                         ? -ENOSR  /* hc couldn't read */
1856                                         : -ECOMM; /* hc couldn't write */
1857                         else if (t & EHCI_ISOC_BABBLE)
1858                                 desc->status = -EOVERFLOW;
1859                         else /* (t & EHCI_ISOC_XACTERR) */
1860                                 desc->status = -EPROTO;
1861
1862                         /* HC need not update length with this error */
1863                         if (!(t & EHCI_ISOC_BABBLE)) {
1864                                 desc->actual_length = EHCI_ITD_LENGTH(t);
1865                                 urb->actual_length += desc->actual_length;
1866                         }
1867                 } else if (likely((t & EHCI_ISOC_ACTIVE) == 0)) {
1868                         desc->status = 0;
1869                         desc->actual_length = EHCI_ITD_LENGTH(t);
1870                         urb->actual_length += desc->actual_length;
1871                 } else {
1872                         /* URB was too late */
1873                         urb->error_count++;
1874                 }
1875         }
1876
1877         /* handle completion now? */
1878         if (likely((urb_index + 1) != urb->number_of_packets))
1879                 goto done;
1880
1881         /*
1882          * ASSERT: it's really the last itd for this urb
1883          * list_for_each_entry (itd, &stream->td_list, itd_list)
1884          *       BUG_ON(itd->urb == urb);
1885          */
1886
1887         /* give urb back to the driver; completion often (re)submits */
1888         ehci_urb_done(ehci, urb, 0);
1889         retval = true;
1890         urb = NULL;
1891
1892         --ehci->isoc_count;
1893         disable_periodic(ehci);
1894
1895         ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs--;
1896         if (ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs == 0) {
1897                 if (ehci->amd_pll_fix == 1)
1898                         usb_amd_quirk_pll_enable();
1899         }
1900
1901         if (unlikely(list_is_singular(&stream->td_list)))
1902                 ehci_to_hcd(ehci)->self.bandwidth_allocated
1903                                 -= stream->bandwidth;
1904
1905 done:
1906         itd->urb = NULL;
1907
1908         /* Add to the end of the free list for later reuse */
1909         list_move_tail(&itd->itd_list, &stream->free_list);
1910
1911         /* Recycle the iTDs when the pipeline is empty (ep no longer in use) */
1912         if (list_empty(&stream->td_list)) {
1913                 list_splice_tail_init(&stream->free_list,
1914                                 &ehci->cached_itd_list);
1915                 start_free_itds(ehci);
1916         }
1917
1918         return retval;
1919 }
1920
1921 /*-------------------------------------------------------------------------*/
1922
1923 static int itd_submit(struct ehci_hcd *ehci, struct urb *urb,
1924         gfp_t mem_flags)
1925 {
1926         int                     status = -EINVAL;
1927         unsigned long           flags;
1928         struct ehci_iso_stream  *stream;
1929
1930         /* Get iso_stream head */
1931         stream = iso_stream_find(ehci, urb);
1932         if (unlikely(stream == NULL)) {
1933                 ehci_dbg(ehci, "can't get iso stream\n");
1934                 return -ENOMEM;
1935         }
1936         if (unlikely(urb->interval != stream->uperiod)) {
1937                 ehci_dbg(ehci, "can't change iso interval %d --> %d\n",
1938                         stream->uperiod, urb->interval);
1939                 goto done;
1940         }
1941
1942 #ifdef EHCI_URB_TRACE
1943         ehci_dbg(ehci,
1944                 "%s %s urb %p ep%d%s len %d, %d pkts %d uframes [%p]\n",
1945                 __func__, urb->dev->devpath, urb,
1946                 usb_pipeendpoint(urb->pipe),
1947                 usb_pipein(urb->pipe) ? "in" : "out",
1948                 urb->transfer_buffer_length,
1949                 urb->number_of_packets, urb->interval,
1950                 stream);
1951 #endif
1952
1953         /* allocate ITDs w/o locking anything */
1954         status = itd_urb_transaction(stream, ehci, urb, mem_flags);
1955         if (unlikely(status < 0)) {
1956                 ehci_dbg(ehci, "can't init itds\n");
1957                 goto done;
1958         }
1959
1960         /* schedule ... need to lock */
1961         spin_lock_irqsave(&ehci->lock, flags);
1962         if (unlikely(!HCD_HW_ACCESSIBLE(ehci_to_hcd(ehci)))) {
1963                 status = -ESHUTDOWN;
1964                 goto done_not_linked;
1965         }
1966         status = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
1967         if (unlikely(status))
1968                 goto done_not_linked;
1969         status = iso_stream_schedule(ehci, urb, stream);
1970         if (likely(status == 0)) {
1971                 itd_link_urb(ehci, urb, ehci->periodic_size << 3, stream);
1972         } else if (status > 0) {
1973                 status = 0;
1974                 ehci_urb_done(ehci, urb, 0);
1975         } else {
1976                 usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
1977         }
1978  done_not_linked:
1979         spin_unlock_irqrestore(&ehci->lock, flags);
1980  done:
1981         return status;
1982 }
1983
1984 /*-------------------------------------------------------------------------*/
1985
1986 /*
1987  * "Split ISO TDs" ... used for USB 1.1 devices going through the
1988  * TTs in USB 2.0 hubs.  These need microframe scheduling.
1989  */
1990
1991 static inline void
1992 sitd_sched_init(
1993         struct ehci_hcd         *ehci,
1994         struct ehci_iso_sched   *iso_sched,
1995         struct ehci_iso_stream  *stream,
1996         struct urb              *urb
1997 )
1998 {
1999         unsigned        i;
2000         dma_addr_t      dma = urb->transfer_dma;
2001
2002         /* how many frames are needed for these transfers */
2003         iso_sched->span = urb->number_of_packets * stream->ps.period;
2004
2005         /* figure out per-frame sitd fields that we'll need later
2006          * when we fit new sitds into the schedule.
2007          */
2008         for (i = 0; i < urb->number_of_packets; i++) {
2009                 struct ehci_iso_packet  *packet = &iso_sched->packet[i];
2010                 unsigned                length;
2011                 dma_addr_t              buf;
2012                 u32                     trans;
2013
2014                 length = urb->iso_frame_desc[i].length & 0x03ff;
2015                 buf = dma + urb->iso_frame_desc[i].offset;
2016
2017                 trans = SITD_STS_ACTIVE;
2018                 if (((i + 1) == urb->number_of_packets)
2019                                 && !(urb->transfer_flags & URB_NO_INTERRUPT))
2020                         trans |= SITD_IOC;
2021                 trans |= length << 16;
2022                 packet->transaction = cpu_to_hc32(ehci, trans);
2023
2024                 /* might need to cross a buffer page within a td */
2025                 packet->bufp = buf;
2026                 packet->buf1 = (buf + length) & ~0x0fff;
2027                 if (packet->buf1 != (buf & ~(u64)0x0fff))
2028                         packet->cross = 1;
2029
2030                 /* OUT uses multiple start-splits */
2031                 if (stream->bEndpointAddress & USB_DIR_IN)
2032                         continue;
2033                 length = (length + 187) / 188;
2034                 if (length > 1) /* BEGIN vs ALL */
2035                         length |= 1 << 3;
2036                 packet->buf1 |= length;
2037         }
2038 }
2039
2040 static int
2041 sitd_urb_transaction(
2042         struct ehci_iso_stream  *stream,
2043         struct ehci_hcd         *ehci,
2044         struct urb              *urb,
2045         gfp_t                   mem_flags
2046 )
2047 {
2048         struct ehci_sitd        *sitd;
2049         dma_addr_t              sitd_dma;
2050         int                     i;
2051         struct ehci_iso_sched   *iso_sched;
2052         unsigned long           flags;
2053
2054         iso_sched = iso_sched_alloc(urb->number_of_packets, mem_flags);
2055         if (iso_sched == NULL)
2056                 return -ENOMEM;
2057
2058         sitd_sched_init(ehci, iso_sched, stream, urb);
2059
2060         /* allocate/init sITDs */
2061         spin_lock_irqsave(&ehci->lock, flags);
2062         for (i = 0; i < urb->number_of_packets; i++) {
2063
2064                 /* NOTE:  for now, we don't try to handle wraparound cases
2065                  * for IN (using sitd->hw_backpointer, like a FSTN), which
2066                  * means we never need two sitds for full speed packets.
2067                  */
2068
2069                 /*
2070                  * Use siTDs from the free list, but not siTDs that may
2071                  * still be in use by the hardware.
2072                  */
2073                 if (likely(!list_empty(&stream->free_list))) {
2074                         sitd = list_first_entry(&stream->free_list,
2075                                          struct ehci_sitd, sitd_list);
2076                         if (sitd->frame == ehci->now_frame)
2077                                 goto alloc_sitd;
2078                         list_del(&sitd->sitd_list);
2079                         sitd_dma = sitd->sitd_dma;
2080                 } else {
2081  alloc_sitd:
2082                         spin_unlock_irqrestore(&ehci->lock, flags);
2083                         sitd = dma_pool_alloc(ehci->sitd_pool, mem_flags,
2084                                         &sitd_dma);
2085                         spin_lock_irqsave(&ehci->lock, flags);
2086                         if (!sitd) {
2087                                 iso_sched_free(stream, iso_sched);
2088                                 spin_unlock_irqrestore(&ehci->lock, flags);
2089                                 return -ENOMEM;
2090                         }
2091                 }
2092
2093                 memset(sitd, 0, sizeof(*sitd));
2094                 sitd->sitd_dma = sitd_dma;
2095                 sitd->frame = NO_FRAME;
2096                 list_add(&sitd->sitd_list, &iso_sched->td_list);
2097         }
2098
2099         /* temporarily store schedule info in hcpriv */
2100         urb->hcpriv = iso_sched;
2101         urb->error_count = 0;
2102
2103         spin_unlock_irqrestore(&ehci->lock, flags);
2104         return 0;
2105 }
2106
2107 /*-------------------------------------------------------------------------*/
2108
2109 static inline void
2110 sitd_patch(
2111         struct ehci_hcd         *ehci,
2112         struct ehci_iso_stream  *stream,
2113         struct ehci_sitd        *sitd,
2114         struct ehci_iso_sched   *iso_sched,
2115         unsigned                index
2116 )
2117 {
2118         struct ehci_iso_packet  *uf = &iso_sched->packet[index];
2119         u64                     bufp;
2120
2121         sitd->hw_next = EHCI_LIST_END(ehci);
2122         sitd->hw_fullspeed_ep = stream->address;
2123         sitd->hw_uframe = stream->splits;
2124         sitd->hw_results = uf->transaction;
2125         sitd->hw_backpointer = EHCI_LIST_END(ehci);
2126
2127         bufp = uf->bufp;
2128         sitd->hw_buf[0] = cpu_to_hc32(ehci, bufp);
2129         sitd->hw_buf_hi[0] = cpu_to_hc32(ehci, bufp >> 32);
2130
2131         sitd->hw_buf[1] = cpu_to_hc32(ehci, uf->buf1);
2132         if (uf->cross)
2133                 bufp += 4096;
2134         sitd->hw_buf_hi[1] = cpu_to_hc32(ehci, bufp >> 32);
2135         sitd->index = index;
2136 }
2137
2138 static inline void
2139 sitd_link(struct ehci_hcd *ehci, unsigned frame, struct ehci_sitd *sitd)
2140 {
2141         /* note: sitd ordering could matter (CSPLIT then SSPLIT) */
2142         sitd->sitd_next = ehci->pshadow[frame];
2143         sitd->hw_next = ehci->periodic[frame];
2144         ehci->pshadow[frame].sitd = sitd;
2145         sitd->frame = frame;
2146         wmb();
2147         ehci->periodic[frame] = cpu_to_hc32(ehci, sitd->sitd_dma | Q_TYPE_SITD);
2148 }
2149
2150 /* fit urb's sitds into the selected schedule slot; activate as needed */
2151 static void sitd_link_urb(
2152         struct ehci_hcd         *ehci,
2153         struct urb              *urb,
2154         unsigned                mod,
2155         struct ehci_iso_stream  *stream
2156 )
2157 {
2158         int                     packet;
2159         unsigned                next_uframe;
2160         struct ehci_iso_sched   *sched = urb->hcpriv;
2161         struct ehci_sitd        *sitd;
2162
2163         next_uframe = stream->next_uframe;
2164
2165         if (list_empty(&stream->td_list))
2166                 /* usbfs ignores TT bandwidth */
2167                 ehci_to_hcd(ehci)->self.bandwidth_allocated
2168                                 += stream->bandwidth;
2169
2170         if (ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs == 0) {
2171                 if (ehci->amd_pll_fix == 1)
2172                         usb_amd_quirk_pll_disable();
2173         }
2174
2175         ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs++;
2176
2177         /* fill sITDs frame by frame */
2178         for (packet = sched->first_packet, sitd = NULL;
2179                         packet < urb->number_of_packets;
2180                         packet++) {
2181
2182                 /* ASSERT:  we have all necessary sitds */
2183                 BUG_ON(list_empty(&sched->td_list));
2184
2185                 /* ASSERT:  no itds for this endpoint in this frame */
2186
2187                 sitd = list_entry(sched->td_list.next,
2188                                 struct ehci_sitd, sitd_list);
2189                 list_move_tail(&sitd->sitd_list, &stream->td_list);
2190                 sitd->stream = stream;
2191                 sitd->urb = urb;
2192
2193                 sitd_patch(ehci, stream, sitd, sched, packet);
2194                 sitd_link(ehci, (next_uframe >> 3) & (ehci->periodic_size - 1),
2195                                 sitd);
2196
2197                 next_uframe += stream->uperiod;
2198         }
2199         stream->next_uframe = next_uframe & (mod - 1);
2200
2201         /* don't need that schedule data any more */
2202         iso_sched_free(stream, sched);
2203         urb->hcpriv = stream;
2204
2205         ++ehci->isoc_count;
2206         enable_periodic(ehci);
2207 }
2208
2209 /*-------------------------------------------------------------------------*/
2210
2211 #define SITD_ERRS (SITD_STS_ERR | SITD_STS_DBE | SITD_STS_BABBLE \
2212                                 | SITD_STS_XACT | SITD_STS_MMF)
2213
2214 /* Process and recycle a completed SITD.  Return true iff its urb completed,
2215  * and hence its completion callback probably added things to the hardware
2216  * schedule.
2217  *
2218  * Note that we carefully avoid recycling this descriptor until after any
2219  * completion callback runs, so that it won't be reused quickly.  That is,
2220  * assuming (a) no more than two urbs per frame on this endpoint, and also
2221  * (b) only this endpoint's completions submit URBs.  It seems some silicon
2222  * corrupts things if you reuse completed descriptors very quickly...
2223  */
2224 static bool sitd_complete(struct ehci_hcd *ehci, struct ehci_sitd *sitd)
2225 {
2226         struct urb                              *urb = sitd->urb;
2227         struct usb_iso_packet_descriptor        *desc;
2228         u32                                     t;
2229         int                                     urb_index;
2230         struct ehci_iso_stream                  *stream = sitd->stream;
2231         bool                                    retval = false;
2232
2233         urb_index = sitd->index;
2234         desc = &urb->iso_frame_desc[urb_index];
2235         t = hc32_to_cpup(ehci, &sitd->hw_results);
2236
2237         /* report transfer status */
2238         if (unlikely(t & SITD_ERRS)) {
2239                 urb->error_count++;
2240                 if (t & SITD_STS_DBE)
2241                         desc->status = usb_pipein(urb->pipe)
2242                                 ? -ENOSR  /* hc couldn't read */
2243                                 : -ECOMM; /* hc couldn't write */
2244                 else if (t & SITD_STS_BABBLE)
2245                         desc->status = -EOVERFLOW;
2246                 else /* XACT, MMF, etc */
2247                         desc->status = -EPROTO;
2248         } else if (unlikely(t & SITD_STS_ACTIVE)) {
2249                 /* URB was too late */
2250                 urb->error_count++;
2251         } else {
2252                 desc->status = 0;
2253                 desc->actual_length = desc->length - SITD_LENGTH(t);
2254                 urb->actual_length += desc->actual_length;
2255         }
2256
2257         /* handle completion now? */
2258         if ((urb_index + 1) != urb->number_of_packets)
2259                 goto done;
2260
2261         /*
2262          * ASSERT: it's really the last sitd for this urb
2263          * list_for_each_entry (sitd, &stream->td_list, sitd_list)
2264          *       BUG_ON(sitd->urb == urb);
2265          */
2266
2267         /* give urb back to the driver; completion often (re)submits */
2268         ehci_urb_done(ehci, urb, 0);
2269         retval = true;
2270         urb = NULL;
2271
2272         --ehci->isoc_count;
2273         disable_periodic(ehci);
2274
2275         ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs--;
2276         if (ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs == 0) {
2277                 if (ehci->amd_pll_fix == 1)
2278                         usb_amd_quirk_pll_enable();
2279         }
2280
2281         if (list_is_singular(&stream->td_list))
2282                 ehci_to_hcd(ehci)->self.bandwidth_allocated
2283                                 -= stream->bandwidth;
2284
2285 done:
2286         sitd->urb = NULL;
2287
2288         /* Add to the end of the free list for later reuse */
2289         list_move_tail(&sitd->sitd_list, &stream->free_list);
2290
2291         /* Recycle the siTDs when the pipeline is empty (ep no longer in use) */
2292         if (list_empty(&stream->td_list)) {
2293                 list_splice_tail_init(&stream->free_list,
2294                                 &ehci->cached_sitd_list);
2295                 start_free_itds(ehci);
2296         }
2297
2298         return retval;
2299 }
2300
2301
2302 static int sitd_submit(struct ehci_hcd *ehci, struct urb *urb,
2303         gfp_t mem_flags)
2304 {
2305         int                     status = -EINVAL;
2306         unsigned long           flags;
2307         struct ehci_iso_stream  *stream;
2308
2309         /* Get iso_stream head */
2310         stream = iso_stream_find(ehci, urb);
2311         if (stream == NULL) {
2312                 ehci_dbg(ehci, "can't get iso stream\n");
2313                 return -ENOMEM;
2314         }
2315         if (urb->interval != stream->ps.period) {
2316                 ehci_dbg(ehci, "can't change iso interval %d --> %d\n",
2317                         stream->ps.period, urb->interval);
2318                 goto done;
2319         }
2320
2321 #ifdef EHCI_URB_TRACE
2322         ehci_dbg(ehci,
2323                 "submit %p dev%s ep%d%s-iso len %d\n",
2324                 urb, urb->dev->devpath,
2325                 usb_pipeendpoint(urb->pipe),
2326                 usb_pipein(urb->pipe) ? "in" : "out",
2327                 urb->transfer_buffer_length);
2328 #endif
2329
2330         /* allocate SITDs */
2331         status = sitd_urb_transaction(stream, ehci, urb, mem_flags);
2332         if (status < 0) {
2333                 ehci_dbg(ehci, "can't init sitds\n");
2334                 goto done;
2335         }
2336
2337         /* schedule ... need to lock */
2338         spin_lock_irqsave(&ehci->lock, flags);
2339         if (unlikely(!HCD_HW_ACCESSIBLE(ehci_to_hcd(ehci)))) {
2340                 status = -ESHUTDOWN;
2341                 goto done_not_linked;
2342         }
2343         status = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
2344         if (unlikely(status))
2345                 goto done_not_linked;
2346         status = iso_stream_schedule(ehci, urb, stream);
2347         if (likely(status == 0)) {
2348                 sitd_link_urb(ehci, urb, ehci->periodic_size << 3, stream);
2349         } else if (status > 0) {
2350                 status = 0;
2351                 ehci_urb_done(ehci, urb, 0);
2352         } else {
2353                 usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
2354         }
2355  done_not_linked:
2356         spin_unlock_irqrestore(&ehci->lock, flags);
2357  done:
2358         return status;
2359 }
2360
2361 /*-------------------------------------------------------------------------*/
2362
2363 static void scan_isoc(struct ehci_hcd *ehci)
2364 {
2365         unsigned                uf, now_frame, frame;
2366         unsigned                fmask = ehci->periodic_size - 1;
2367         bool                    modified, live;
2368         union ehci_shadow       q, *q_p;
2369         __hc32                  type, *hw_p;
2370
2371         /*
2372          * When running, scan from last scan point up to "now"
2373          * else clean up by scanning everything that's left.
2374          * Touches as few pages as possible:  cache-friendly.
2375          */
2376         if (ehci->rh_state >= EHCI_RH_RUNNING) {
2377                 uf = ehci_read_frame_index(ehci);
2378                 now_frame = (uf >> 3) & fmask;
2379                 live = true;
2380         } else  {
2381                 now_frame = (ehci->last_iso_frame - 1) & fmask;
2382                 live = false;
2383         }
2384         ehci->now_frame = now_frame;
2385
2386         frame = ehci->last_iso_frame;
2387
2388 restart:
2389         /* Scan each element in frame's queue for completions */
2390         q_p = &ehci->pshadow[frame];
2391         hw_p = &ehci->periodic[frame];
2392         q.ptr = q_p->ptr;
2393         type = Q_NEXT_TYPE(ehci, *hw_p);
2394         modified = false;
2395
2396         while (q.ptr != NULL) {
2397                 switch (hc32_to_cpu(ehci, type)) {
2398                 case Q_TYPE_ITD:
2399                         /*
2400                          * If this ITD is still active, leave it for
2401                          * later processing ... check the next entry.
2402                          * No need to check for activity unless the
2403                          * frame is current.
2404                          */
2405                         if (frame == now_frame && live) {
2406                                 rmb();
2407                                 for (uf = 0; uf < 8; uf++) {
2408                                         if (q.itd->hw_transaction[uf] &
2409                                                         ITD_ACTIVE(ehci))
2410                                                 break;
2411                                 }
2412                                 if (uf < 8) {
2413                                         q_p = &q.itd->itd_next;
2414                                         hw_p = &q.itd->hw_next;
2415                                         type = Q_NEXT_TYPE(ehci,
2416                                                         q.itd->hw_next);
2417                                         q = *q_p;
2418                                         break;
2419                                 }
2420                         }
2421
2422                         /*
2423                          * Take finished ITDs out of the schedule
2424                          * and process them:  recycle, maybe report
2425                          * URB completion.  HC won't cache the
2426                          * pointer for much longer, if at all.
2427                          */
2428                         *q_p = q.itd->itd_next;
2429                         if (!ehci->use_dummy_qh ||
2430                                         q.itd->hw_next != EHCI_LIST_END(ehci))
2431                                 *hw_p = q.itd->hw_next;
2432                         else
2433                                 *hw_p = cpu_to_hc32(ehci, ehci->dummy->qh_dma);
2434                         type = Q_NEXT_TYPE(ehci, q.itd->hw_next);
2435                         wmb();
2436                         modified = itd_complete(ehci, q.itd);
2437                         q = *q_p;
2438                         break;
2439                 case Q_TYPE_SITD:
2440                         /*
2441                          * If this SITD is still active, leave it for
2442                          * later processing ... check the next entry.
2443                          * No need to check for activity unless the
2444                          * frame is current.
2445                          */
2446                         if (((frame == now_frame) ||
2447                                         (((frame + 1) & fmask) == now_frame))
2448                                 && live
2449                                 && (q.sitd->hw_results & SITD_ACTIVE(ehci))) {
2450
2451                                 q_p = &q.sitd->sitd_next;
2452                                 hw_p = &q.sitd->hw_next;
2453                                 type = Q_NEXT_TYPE(ehci, q.sitd->hw_next);
2454                                 q = *q_p;
2455                                 break;
2456                         }
2457
2458                         /*
2459                          * Take finished SITDs out of the schedule
2460                          * and process them:  recycle, maybe report
2461                          * URB completion.
2462                          */
2463                         *q_p = q.sitd->sitd_next;
2464                         if (!ehci->use_dummy_qh ||
2465                                         q.sitd->hw_next != EHCI_LIST_END(ehci))
2466                                 *hw_p = q.sitd->hw_next;
2467                         else
2468                                 *hw_p = cpu_to_hc32(ehci, ehci->dummy->qh_dma);
2469                         type = Q_NEXT_TYPE(ehci, q.sitd->hw_next);
2470                         wmb();
2471                         modified = sitd_complete(ehci, q.sitd);
2472                         q = *q_p;
2473                         break;
2474                 default:
2475                         ehci_dbg(ehci, "corrupt type %d frame %d shadow %p\n",
2476                                         type, frame, q.ptr);
2477                         /* BUG(); */
2478                         /* FALL THROUGH */
2479                 case Q_TYPE_QH:
2480                 case Q_TYPE_FSTN:
2481                         /* End of the iTDs and siTDs */
2482                         q.ptr = NULL;
2483                         break;
2484                 }
2485
2486                 /* Assume completion callbacks modify the queue */
2487                 if (unlikely(modified && ehci->isoc_count > 0))
2488                         goto restart;
2489         }
2490
2491         /* Stop when we have reached the current frame */
2492         if (frame == now_frame)
2493                 return;
2494
2495         /* The last frame may still have active siTDs */
2496         ehci->last_iso_frame = frame;
2497         frame = (frame + 1) & fmask;
2498
2499         goto restart;
2500 }