git.oblomov.eu Git - linux-2.6/blob - drivers/usb/host/ehci-sched.c

   1 /*
   2  * Copyright (c) 2001-2004 by David Brownell
   3  * Copyright (c) 2003 Michal Sojka, for high-speed iso transfers
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by the
   7  * Free Software Foundation; either version 2 of the License, or (at your
   8  * option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  12  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software Foundation,
  17  * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  */
  19
  20 /* this file is part of ehci-hcd.c */
  21
  22 /*-------------------------------------------------------------------------*/
  23
  24 /*
  25  * EHCI scheduled transaction support:  interrupt, iso, split iso
  26  * These are called "periodic" transactions in the EHCI spec.
  27  *
  28  * Note that for interrupt transfers, the QH/QTD manipulation is shared
  29  * with the "asynchronous" transaction support (control/bulk transfers).
  30  * The only real difference is in how interrupt transfers are scheduled.
  31  *
  32  * For ISO, we make an "iso_stream" head to serve the same role as a QH.
  33  * It keeps track of every ITD (or SITD) that's linked, and holds enough
  34  * pre-calculated schedule data to make appending to the queue be quick.
  35  */
  36
  37 static int ehci_get_frame (struct usb_hcd *hcd);
  38
  39 /*-------------------------------------------------------------------------*/
  40
  41 /*
  42  * periodic_next_shadow - return "next" pointer on shadow list
  43  * @periodic: host pointer to qh/itd/sitd
  44  * @tag: hardware tag for type of this record
  45  */
  46 static union ehci_shadow *
  47 periodic_next_shadow (union ehci_shadow *periodic, __le32 tag)
  48 {
  49         switch (tag) {
  50         case Q_TYPE_QH:
  51                 return &periodic->qh->qh_next;
  52         case Q_TYPE_FSTN:
  53                 return &periodic->fstn->fstn_next;
  54         case Q_TYPE_ITD:
  55                 return &periodic->itd->itd_next;
  56         // case Q_TYPE_SITD:
  57         default:
  58                 return &periodic->sitd->sitd_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         __le32                  *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 (prev_p, Q_NEXT_TYPE (*hw_p));
  72                 hw_p = here.hw_next;
  73                 here = *prev_p;
  74         }
  75         /* an interrupt entry (at list end) could have been shared */
  76         if (!here.ptr)
  77                 return;
  78
  79         /* update shadow and hardware lists ... the old "next" pointers
  80          * from ptr may still be in use, the caller updates them.
  81          */
  82         *prev_p = *periodic_next_shadow (&here, Q_NEXT_TYPE (*hw_p));
  83         *hw_p = *here.hw_next;
  84 }
  85
  86 /* how many of the uframe's 125 usecs are allocated? */
  87 static unsigned short
  88 periodic_usecs (struct ehci_hcd *ehci, unsigned frame, unsigned uframe)
  89 {
  90         __le32                  *hw_p = &ehci->periodic [frame];
  91         union ehci_shadow       *q = &ehci->pshadow [frame];
  92         unsigned                usecs = 0;
  93
  94         while (q->ptr) {
  95                 switch (Q_NEXT_TYPE (*hw_p)) {
  96                 case Q_TYPE_QH:
  97                         /* is it in the S-mask? */
  98                         if (q->qh->hw_info2 & cpu_to_le32 (1 << uframe))
  99                                 usecs += q->qh->usecs;
 100                         /* ... or C-mask? */
 101                         if (q->qh->hw_info2 & cpu_to_le32 (1 << (8 + uframe)))
 102                                 usecs += q->qh->c_usecs;
 103                         hw_p = &q->qh->hw_next;
 104                         q = &q->qh->qh_next;
 105                         break;
 106                 // case Q_TYPE_FSTN:
 107                 default:
 108                         /* for "save place" FSTNs, count the relevant INTR
 109                          * bandwidth from the previous frame
 110                          */
 111                         if (q->fstn->hw_prev != EHCI_LIST_END) {
 112                                 ehci_dbg (ehci, "ignoring FSTN cost ...\n");
 113                         }
 114                         hw_p = &q->fstn->hw_next;
 115                         q = &q->fstn->fstn_next;
 116                         break;
 117                 case Q_TYPE_ITD:
 118                         usecs += q->itd->usecs [uframe];
 119                         hw_p = &q->itd->hw_next;
 120                         q = &q->itd->itd_next;
 121                         break;
 122                 case Q_TYPE_SITD:
 123                         /* is it in the S-mask?  (count SPLIT, DATA) */
 124                         if (q->sitd->hw_uframe & cpu_to_le32 (1 << uframe)) {
 125                                 if (q->sitd->hw_fullspeed_ep &
 126                                                 __constant_cpu_to_le32 (1<<31))
 127                                         usecs += q->sitd->stream->usecs;
 128                                 else    /* worst case for OUT start-split */
 129                                         usecs += HS_USECS_ISO (188);
 130                         }
 131
 132                         /* ... C-mask?  (count CSPLIT, DATA) */
 133                         if (q->sitd->hw_uframe &
 134                                         cpu_to_le32 (1 << (8 + uframe))) {
 135                                 /* worst case for IN complete-split */
 136                                 usecs += q->sitd->stream->c_usecs;
 137                         }
 138
 139                         hw_p = &q->sitd->hw_next;
 140                         q = &q->sitd->sitd_next;
 141                         break;
 142                 }
 143         }
 144 #ifdef  DEBUG
 145         if (usecs > 100)
 146                 ehci_err (ehci, "uframe %d sched overrun: %d usecs\n",
 147                         frame * 8 + uframe, usecs);
 148 #endif
 149         return usecs;
 150 }
 151
 152 /*-------------------------------------------------------------------------*/
 153
 154 static int same_tt (struct usb_device *dev1, struct usb_device *dev2)
 155 {
 156         if (!dev1->tt || !dev2->tt)
 157                 return 0;
 158         if (dev1->tt != dev2->tt)
 159                 return 0;
 160         if (dev1->tt->multi)
 161                 return dev1->ttport == dev2->ttport;
 162         else
 163                 return 1;
 164 }
 165
 166 /* return true iff the device's transaction translator is available
 167  * for a periodic transfer starting at the specified frame, using
 168  * all the uframes in the mask.
 169  */
 170 static int tt_no_collision (
 171         struct ehci_hcd         *ehci,
 172         unsigned                period,
 173         struct usb_device       *dev,
 174         unsigned                frame,
 175         u32                     uf_mask
 176 )
 177 {
 178         if (period == 0)        /* error */
 179                 return 0;
 180
 181         /* note bandwidth wastage:  split never follows csplit
 182          * (different dev or endpoint) until the next uframe.
 183          * calling convention doesn't make that distinction.
 184          */
 185         for (; frame < ehci->periodic_size; frame += period) {
 186                 union ehci_shadow       here;
 187                 __le32                  type;
 188
 189                 here = ehci->pshadow [frame];
 190                 type = Q_NEXT_TYPE (ehci->periodic [frame]);
 191                 while (here.ptr) {
 192                         switch (type) {
 193                         case Q_TYPE_ITD:
 194                                 type = Q_NEXT_TYPE (here.itd->hw_next);
 195                                 here = here.itd->itd_next;
 196                                 continue;
 197                         case Q_TYPE_QH:
 198                                 if (same_tt (dev, here.qh->dev)) {
 199                                         u32             mask;
 200
 201                                         mask = le32_to_cpu (here.qh->hw_info2);
 202                                         /* "knows" no gap is needed */
 203                                         mask |= mask >> 8;
 204                                         if (mask & uf_mask)
 205                                                 break;
 206                                 }
 207                                 type = Q_NEXT_TYPE (here.qh->hw_next);
 208                                 here = here.qh->qh_next;
 209                                 continue;
 210                         case Q_TYPE_SITD:
 211                                 if (same_tt (dev, here.sitd->urb->dev)) {
 212                                         u16             mask;
 213
 214                                         mask = le32_to_cpu (here.sitd
 215                                                                 ->hw_uframe);
 216                                         /* FIXME assumes no gap for IN! */
 217                                         mask |= mask >> 8;
 218                                         if (mask & uf_mask)
 219                                                 break;
 220                                 }
 221                                 type = Q_NEXT_TYPE (here.sitd->hw_next);
 222                                 here = here.sitd->sitd_next;
 223                                 continue;
 224                         // case Q_TYPE_FSTN:
 225                         default:
 226                                 ehci_dbg (ehci,
 227                                         "periodic frame %d bogus type %d\n",
 228                                         frame, type);
 229                         }
 230
 231                         /* collision or error */
 232                         return 0;
 233                 }
 234         }
 235
 236         /* no collision */
 237         return 1;
 238 }
 239
 240 /*-------------------------------------------------------------------------*/
 241
 242 static int enable_periodic (struct ehci_hcd *ehci)
 243 {
 244         u32     cmd;
 245         int     status;
 246
 247         /* did clearing PSE did take effect yet?
 248          * takes effect only at frame boundaries...
 249          */
 250         status = handshake (&ehci->regs->status, STS_PSS, 0, 9 * 125);
 251         if (status != 0) {
 252                 ehci_to_hcd(ehci)->state = HC_STATE_HALT;
 253                 return status;
 254         }
 255
 256         cmd = readl (&ehci->regs->command) | CMD_PSE;
 257         writel (cmd, &ehci->regs->command);
 258         /* posted write ... PSS happens later */
 259         ehci_to_hcd(ehci)->state = HC_STATE_RUNNING;
 260
 261         /* make sure ehci_work scans these */
 262         ehci->next_uframe = readl (&ehci->regs->frame_index)
 263                                 % (ehci->periodic_size << 3);
 264         return 0;
 265 }
 266
 267 static int disable_periodic (struct ehci_hcd *ehci)
 268 {
 269         u32     cmd;
 270         int     status;
 271
 272         /* did setting PSE not take effect yet?
 273          * takes effect only at frame boundaries...
 274          */
 275         status = handshake (&ehci->regs->status, STS_PSS, STS_PSS, 9 * 125);
 276         if (status != 0) {
 277                 ehci_to_hcd(ehci)->state = HC_STATE_HALT;
 278                 return status;
 279         }
 280
 281         cmd = readl (&ehci->regs->command) & ~CMD_PSE;
 282         writel (cmd, &ehci->regs->command);
 283         /* posted write ... */
 284
 285         ehci->next_uframe = -1;
 286         return 0;
 287 }
 288
 289 /*-------------------------------------------------------------------------*/
 290
 291 /* periodic schedule slots have iso tds (normal or split) first, then a
 292  * sparse tree for active interrupt transfers.
 293  *
 294  * this just links in a qh; caller guarantees uframe masks are set right.
 295  * no FSTN support (yet; ehci 0.96+)
 296  */
 297 static int qh_link_periodic (struct ehci_hcd *ehci, struct ehci_qh *qh)
 298 {
 299         unsigned        i;
 300         unsigned        period = qh->period;
 301
 302         dev_dbg (&qh->dev->dev,
 303                 "link qh%d-%04x/%p start %d [%d/%d us]\n",
 304                 period, le32_to_cpup (&qh->hw_info2) & (QH_CMASK | QH_SMASK),
 305                 qh, qh->start, qh->usecs, qh->c_usecs);
 306
 307         /* high bandwidth, or otherwise every microframe */
 308         if (period == 0)
 309                 period = 1;
 310
 311         for (i = qh->start; i < ehci->periodic_size; i += period) {
 312                 union ehci_shadow       *prev = &ehci->pshadow [i];
 313                 __le32                  *hw_p = &ehci->periodic [i];
 314                 union ehci_shadow       here = *prev;
 315                 __le32                  type = 0;
 316
 317                 /* skip the iso nodes at list head */
 318                 while (here.ptr) {
 319                         type = Q_NEXT_TYPE (*hw_p);
 320                         if (type == Q_TYPE_QH)
 321                                 break;
 322                         prev = periodic_next_shadow (prev, type);
 323                         hw_p = &here.qh->hw_next;
 324                         here = *prev;
 325                 }
 326
 327                 /* sorting each branch by period (slow-->fast)
 328                  * enables sharing interior tree nodes
 329                  */
 330                 while (here.ptr && qh != here.qh) {
 331                         if (qh->period > here.qh->period)
 332                                 break;
 333                         prev = &here.qh->qh_next;
 334                         hw_p = &here.qh->hw_next;
 335                         here = *prev;
 336                 }
 337                 /* link in this qh, unless some earlier pass did that */
 338                 if (qh != here.qh) {
 339                         qh->qh_next = here;
 340                         if (here.qh)
 341                                 qh->hw_next = *hw_p;
 342                         wmb ();
 343                         prev->qh = qh;
 344                         *hw_p = QH_NEXT (qh->qh_dma);
 345                 }
 346         }
 347         qh->qh_state = QH_STATE_LINKED;
 348         qh_get (qh);
 349
 350         /* update per-qh bandwidth for usbfs */
 351         ehci_to_hcd(ehci)->self.bandwidth_allocated += qh->period
 352                 ? ((qh->usecs + qh->c_usecs) / qh->period)
 353                 : (qh->usecs * 8);
 354
 355         /* maybe enable periodic schedule processing */
 356         if (!ehci->periodic_sched++)
 357                 return enable_periodic (ehci);
 358
 359         return 0;
 360 }
 361
 362 static void qh_unlink_periodic (struct ehci_hcd *ehci, struct ehci_qh *qh)
 363 {
 364         unsigned        i;
 365         unsigned        period;
 366
 367         // FIXME:
 368         // IF this isn't high speed
 369         //   and this qh is active in the current uframe
 370         //   (and overlay token SplitXstate is false?)
 371         // THEN
 372         //   qh->hw_info1 |= __constant_cpu_to_le32 (1 << 7 /* "ignore" */);
 373
 374         /* high bandwidth, or otherwise part of every microframe */
 375         if ((period = qh->period) == 0)
 376                 period = 1;
 377
 378         for (i = qh->start; i < ehci->periodic_size; i += period)
 379                 periodic_unlink (ehci, i, qh);
 380
 381         /* update per-qh bandwidth for usbfs */
 382         ehci_to_hcd(ehci)->self.bandwidth_allocated -= qh->period
 383                 ? ((qh->usecs + qh->c_usecs) / qh->period)
 384                 : (qh->usecs * 8);
 385
 386         dev_dbg (&qh->dev->dev,
 387                 "unlink qh%d-%04x/%p start %d [%d/%d us]\n",
 388                 qh->period,
 389                 le32_to_cpup (&qh->hw_info2) & (QH_CMASK | QH_SMASK),
 390                 qh, qh->start, qh->usecs, qh->c_usecs);
 391
 392         /* qh->qh_next still "live" to HC */
 393         qh->qh_state = QH_STATE_UNLINK;
 394         qh->qh_next.ptr = NULL;
 395         qh_put (qh);
 396
 397         /* maybe turn off periodic schedule */
 398         ehci->periodic_sched--;
 399         if (!ehci->periodic_sched)
 400                 (void) disable_periodic (ehci);
 401 }
 402
 403 static void intr_deschedule (struct ehci_hcd *ehci, struct ehci_qh *qh)
 404 {
 405         unsigned        wait;
 406
 407         qh_unlink_periodic (ehci, qh);
 408
 409         /* simple/paranoid:  always delay, expecting the HC needs to read
 410          * qh->hw_next or finish a writeback after SPLIT/CSPLIT ... and
 411          * expect khubd to clean up after any CSPLITs we won't issue.
 412          * active high speed queues may need bigger delays...
 413          */
 414         if (list_empty (&qh->qtd_list)
 415                         || (__constant_cpu_to_le32 (QH_CMASK)
 416                                         & qh->hw_info2) != 0)
 417                 wait = 2;
 418         else
 419                 wait = 55;      /* worst case: 3 * 1024 */
 420
 421         udelay (wait);
 422         qh->qh_state = QH_STATE_IDLE;
 423         qh->hw_next = EHCI_LIST_END;
 424         wmb ();
 425 }
 426
 427 /*-------------------------------------------------------------------------*/
 428
 429 static int check_period (
 430         struct ehci_hcd *ehci,
 431         unsigned        frame,
 432         unsigned        uframe,
 433         unsigned        period,
 434         unsigned        usecs
 435 ) {
 436         int             claimed;
 437
 438         /* complete split running into next frame?
 439          * given FSTN support, we could sometimes check...
 440          */
 441         if (uframe >= 8)
 442                 return 0;
 443
 444         /*
 445          * 80% periodic == 100 usec/uframe available
 446          * convert "usecs we need" to "max already claimed"
 447          */
 448         usecs = 100 - usecs;
 449
 450         /* we "know" 2 and 4 uframe intervals were rejected; so
 451          * for period 0, check _every_ microframe in the schedule.
 452          */
 453         if (unlikely (period == 0)) {
 454                 do {
 455                         for (uframe = 0; uframe < 7; uframe++) {
 456                                 claimed = periodic_usecs (ehci, frame, uframe);
 457                                 if (claimed > usecs)
 458                                         return 0;
 459                         }
 460                 } while ((frame += 1) < ehci->periodic_size);
 461
 462         /* just check the specified uframe, at that period */
 463         } else {
 464                 do {
 465                         claimed = periodic_usecs (ehci, frame, uframe);
 466                         if (claimed > usecs)
 467                                 return 0;
 468                 } while ((frame += period) < ehci->periodic_size);
 469         }
 470
 471         // success!
 472         return 1;
 473 }
 474
 475 static int check_intr_schedule (
 476         struct ehci_hcd         *ehci,
 477         unsigned                frame,
 478         unsigned                uframe,
 479         const struct ehci_qh    *qh,
 480         __le32                  *c_maskp
 481 )
 482 {
 483         int             retval = -ENOSPC;
 484         u8              mask;
 485
 486         if (qh->c_usecs && uframe >= 6)         /* FSTN territory? */
 487                 goto done;
 488
 489         if (!check_period (ehci, frame, uframe, qh->period, qh->usecs))
 490                 goto done;
 491         if (!qh->c_usecs) {
 492                 retval = 0;
 493                 *c_maskp = 0;
 494                 goto done;
 495         }
 496
 497         /* Make sure this tt's buffer is also available for CSPLITs.
 498          * We pessimize a bit; probably the typical full speed case
 499          * doesn't need the second CSPLIT.
 500          *
 501          * NOTE:  both SPLIT and CSPLIT could be checked in just
 502          * one smart pass...
 503          */
 504         mask = 0x03 << (uframe + qh->gap_uf);
 505         *c_maskp = cpu_to_le32 (mask << 8);
 506
 507         mask |= 1 << uframe;
 508         if (tt_no_collision (ehci, qh->period, qh->dev, frame, mask)) {
 509                 if (!check_period (ehci, frame, uframe + qh->gap_uf + 1,
 510                                         qh->period, qh->c_usecs))
 511                         goto done;
 512                 if (!check_period (ehci, frame, uframe + qh->gap_uf,
 513                                         qh->period, qh->c_usecs))
 514                         goto done;
 515                 retval = 0;
 516         }
 517 done:
 518         return retval;
 519 }
 520
 521 /* "first fit" scheduling policy used the first time through,
 522  * or when the previous schedule slot can't be re-used.
 523  */
 524 static int qh_schedule (struct ehci_hcd *ehci, struct ehci_qh *qh)
 525 {
 526         int             status;
 527         unsigned        uframe;
 528         __le32          c_mask;
 529         unsigned        frame;          /* 0..(qh->period - 1), or NO_FRAME */
 530
 531         qh_refresh(ehci, qh);
 532         qh->hw_next = EHCI_LIST_END;
 533         frame = qh->start;
 534
 535         /* reuse the previous schedule slots, if we can */
 536         if (frame < qh->period) {
 537                 uframe = ffs (le32_to_cpup (&qh->hw_info2) & QH_SMASK);
 538                 status = check_intr_schedule (ehci, frame, --uframe,
 539                                 qh, &c_mask);
 540         } else {
 541                 uframe = 0;
 542                 c_mask = 0;
 543                 status = -ENOSPC;
 544         }
 545
 546         /* else scan the schedule to find a group of slots such that all
 547          * uframes have enough periodic bandwidth available.
 548          */
 549         if (status) {
 550                 /* "normal" case, uframing flexible except with splits */
 551                 if (qh->period) {
 552                         frame = qh->period - 1;
 553                         do {
 554                                 for (uframe = 0; uframe < 8; uframe++) {
 555                                         status = check_intr_schedule (ehci,
 556                                                         frame, uframe, qh,
 557                                                         &c_mask);
 558                                         if (status == 0)
 559                                                 break;
 560                                 }
 561                         } while (status && frame--);
 562
 563                 /* qh->period == 0 means every uframe */
 564                 } else {
 565                         frame = 0;
 566                         status = check_intr_schedule (ehci, 0, 0, qh, &c_mask);
 567                 }
 568                 if (status)
 569                         goto done;
 570                 qh->start = frame;
 571
 572                 /* reset S-frame and (maybe) C-frame masks */
 573                 qh->hw_info2 &= __constant_cpu_to_le32(~(QH_CMASK | QH_SMASK));
 574                 qh->hw_info2 |= qh->period
 575                         ? cpu_to_le32 (1 << uframe)
 576                         : __constant_cpu_to_le32 (QH_SMASK);
 577                 qh->hw_info2 |= c_mask;
 578         } else
 579                 ehci_dbg (ehci, "reused qh %p schedule\n", qh);
 580
 581         /* stuff into the periodic schedule */
 582         status = qh_link_periodic (ehci, qh);
 583 done:
 584         return status;
 585 }
 586
 587 static int intr_submit (
 588         struct ehci_hcd         *ehci,
 589         struct usb_host_endpoint *ep,
 590         struct urb              *urb,
 591         struct list_head        *qtd_list,
 592         gfp_t                   mem_flags
 593 ) {
 594         unsigned                epnum;
 595         unsigned long           flags;
 596         struct ehci_qh          *qh;
 597         int                     status = 0;
 598         struct list_head        empty;
 599
 600         /* get endpoint and transfer/schedule data */
 601         epnum = ep->desc.bEndpointAddress;
 602
 603         spin_lock_irqsave (&ehci->lock, flags);
 604
 605         /* get qh and force any scheduling errors */
 606         INIT_LIST_HEAD (&empty);
 607         qh = qh_append_tds (ehci, urb, &empty, epnum, &ep->hcpriv);
 608         if (qh == NULL) {
 609                 status = -ENOMEM;
 610                 goto done;
 611         }
 612         if (qh->qh_state == QH_STATE_IDLE) {
 613                 if ((status = qh_schedule (ehci, qh)) != 0)
 614                         goto done;
 615         }
 616
 617         /* then queue the urb's tds to the qh */
 618         qh = qh_append_tds (ehci, urb, qtd_list, epnum, &ep->hcpriv);
 619         BUG_ON (qh == NULL);
 620
 621         /* ... update usbfs periodic stats */
 622         ehci_to_hcd(ehci)->self.bandwidth_int_reqs++;
 623
 624 done:
 625         spin_unlock_irqrestore (&ehci->lock, flags);
 626         if (status)
 627                 qtd_list_free (ehci, urb, qtd_list);
 628
 629         return status;
 630 }
 631
 632 /*-------------------------------------------------------------------------*/
 633
 634 /* ehci_iso_stream ops work with both ITD and SITD */
 635
 636 static struct ehci_iso_stream *
 637 iso_stream_alloc (gfp_t mem_flags)
 638 {
 639         struct ehci_iso_stream *stream;
 640
 641         stream = kzalloc(sizeof *stream, mem_flags);
 642         if (likely (stream != NULL)) {
 643                 INIT_LIST_HEAD(&stream->td_list);
 644                 INIT_LIST_HEAD(&stream->free_list);
 645                 stream->next_uframe = -1;
 646                 stream->refcount = 1;
 647         }
 648         return stream;
 649 }
 650
 651 static void
 652 iso_stream_init (
 653         struct ehci_hcd         *ehci,
 654         struct ehci_iso_stream  *stream,
 655         struct usb_device       *dev,
 656         int                     pipe,
 657         unsigned                interval
 658 )
 659 {
 660         static const u8 smask_out [] = { 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f };
 661
 662         u32                     buf1;
 663         unsigned                epnum, maxp;
 664         int                     is_input;
 665         long                    bandwidth;
 666
 667         /*
 668          * this might be a "high bandwidth" highspeed endpoint,
 669          * as encoded in the ep descriptor's wMaxPacket field
 670          */
 671         epnum = usb_pipeendpoint (pipe);
 672         is_input = usb_pipein (pipe) ? USB_DIR_IN : 0;
 673         maxp = usb_maxpacket(dev, pipe, !is_input);
 674         if (is_input) {
 675                 buf1 = (1 << 11);
 676         } else {
 677                 buf1 = 0;
 678         }
 679
 680         /* knows about ITD vs SITD */
 681         if (dev->speed == USB_SPEED_HIGH) {
 682                 unsigned multi = hb_mult(maxp);
 683
 684                 stream->highspeed = 1;
 685
 686                 maxp = max_packet(maxp);
 687                 buf1 |= maxp;
 688                 maxp *= multi;
 689
 690                 stream->buf0 = cpu_to_le32 ((epnum << 8) | dev->devnum);
 691                 stream->buf1 = cpu_to_le32 (buf1);
 692                 stream->buf2 = cpu_to_le32 (multi);
 693
 694                 /* usbfs wants to report the average usecs per frame tied up
 695                  * when transfers on this endpoint are scheduled ...
 696                  */
 697                 stream->usecs = HS_USECS_ISO (maxp);
 698                 bandwidth = stream->usecs * 8;
 699                 bandwidth /= 1 << (interval - 1);
 700
 701         } else {
 702                 u32             addr;
 703                 int             think_time;
 704
 705                 addr = dev->ttport << 24;
 706                 if (!ehci_is_TDI(ehci)
 707                                 || (dev->tt->hub !=
 708                                         ehci_to_hcd(ehci)->self.root_hub))
 709                         addr |= dev->tt->hub->devnum << 16;
 710                 addr |= epnum << 8;
 711                 addr |= dev->devnum;
 712                 stream->usecs = HS_USECS_ISO (maxp);
 713                 think_time = dev->tt ? dev->tt->think_time : 0;
 714                 stream->tt_usecs = NS_TO_US (think_time + usb_calc_bus_time (
 715                                 dev->speed, is_input, 1, maxp));
 716                 if (is_input) {
 717                         u32     tmp;
 718
 719                         addr |= 1 << 31;
 720                         stream->c_usecs = stream->usecs;
 721                         stream->usecs = HS_USECS_ISO (1);
 722                         stream->raw_mask = 1;
 723
 724                         /* pessimistic c-mask */
 725                         tmp = usb_calc_bus_time (USB_SPEED_FULL, 1, 0, maxp)
 726                                         / (125 * 1000);
 727                         stream->raw_mask |= 3 << (tmp + 9);
 728                 } else
 729                         stream->raw_mask = smask_out [maxp / 188];
 730                 bandwidth = stream->usecs + stream->c_usecs;
 731                 bandwidth /= 1 << (interval + 2);
 732
 733                 /* stream->splits gets created from raw_mask later */
 734                 stream->address = cpu_to_le32 (addr);
 735         }
 736         stream->bandwidth = bandwidth;
 737
 738         stream->udev = dev;
 739
 740         stream->bEndpointAddress = is_input | epnum;
 741         stream->interval = interval;
 742         stream->maxp = maxp;
 743 }
 744
 745 static void
 746 iso_stream_put(struct ehci_hcd *ehci, struct ehci_iso_stream *stream)
 747 {
 748         stream->refcount--;
 749
 750         /* free whenever just a dev->ep reference remains.
 751          * not like a QH -- no persistent state (toggle, halt)
 752          */
 753         if (stream->refcount == 1) {
 754                 int             is_in;
 755
 756                 // BUG_ON (!list_empty(&stream->td_list));
 757
 758                 while (!list_empty (&stream->free_list)) {
 759                         struct list_head        *entry;
 760
 761                         entry = stream->free_list.next;
 762                         list_del (entry);
 763
 764                         /* knows about ITD vs SITD */
 765                         if (stream->highspeed) {
 766                                 struct ehci_itd         *itd;
 767
 768                                 itd = list_entry (entry, struct ehci_itd,
 769                                                 itd_list);
 770                                 dma_pool_free (ehci->itd_pool, itd,
 771                                                 itd->itd_dma);
 772                         } else {
 773                                 struct ehci_sitd        *sitd;
 774
 775                                 sitd = list_entry (entry, struct ehci_sitd,
 776                                                 sitd_list);
 777                                 dma_pool_free (ehci->sitd_pool, sitd,
 778                                                 sitd->sitd_dma);
 779                         }
 780                 }
 781
 782                 is_in = (stream->bEndpointAddress & USB_DIR_IN) ? 0x10 : 0;
 783                 stream->bEndpointAddress &= 0x0f;
 784                 stream->ep->hcpriv = NULL;
 785
 786                 if (stream->rescheduled) {
 787                         ehci_info (ehci, "ep%d%s-iso rescheduled "
 788                                 "%lu times in %lu seconds\n",
 789                                 stream->bEndpointAddress, is_in ? "in" : "out",
 790                                 stream->rescheduled,
 791                                 ((jiffies - stream->start)/HZ)
 792                                 );
 793                 }
 794
 795                 kfree(stream);
 796         }
 797 }
 798
 799 static inline struct ehci_iso_stream *
 800 iso_stream_get (struct ehci_iso_stream *stream)
 801 {
 802         if (likely (stream != NULL))
 803                 stream->refcount++;
 804         return stream;
 805 }
 806
 807 static struct ehci_iso_stream *
 808 iso_stream_find (struct ehci_hcd *ehci, struct urb *urb)
 809 {
 810         unsigned                epnum;
 811         struct ehci_iso_stream  *stream;
 812         struct usb_host_endpoint *ep;
 813         unsigned long           flags;
 814
 815         epnum = usb_pipeendpoint (urb->pipe);
 816         if (usb_pipein(urb->pipe))
 817                 ep = urb->dev->ep_in[epnum];
 818         else
 819                 ep = urb->dev->ep_out[epnum];
 820
 821         spin_lock_irqsave (&ehci->lock, flags);
 822         stream = ep->hcpriv;
 823
 824         if (unlikely (stream == NULL)) {
 825                 stream = iso_stream_alloc(GFP_ATOMIC);
 826                 if (likely (stream != NULL)) {
 827                         /* dev->ep owns the initial refcount */
 828                         ep->hcpriv = stream;
 829                         stream->ep = ep;
 830                         iso_stream_init(ehci, stream, urb->dev, urb->pipe,
 831                                         urb->interval);
 832                 }
 833
 834         /* if dev->ep [epnum] is a QH, info1.maxpacket is nonzero */
 835         } else if (unlikely (stream->hw_info1 != 0)) {
 836                 ehci_dbg (ehci, "dev %s ep%d%s, not iso??\n",
 837                         urb->dev->devpath, epnum,
 838                         usb_pipein(urb->pipe) ? "in" : "out");
 839                 stream = NULL;
 840         }
 841
 842         /* caller guarantees an eventual matching iso_stream_put */
 843         stream = iso_stream_get (stream);
 844
 845         spin_unlock_irqrestore (&ehci->lock, flags);
 846         return stream;
 847 }
 848
 849 /*-------------------------------------------------------------------------*/
 850
 851 /* ehci_iso_sched ops can be ITD-only or SITD-only */
 852
 853 static struct ehci_iso_sched *
 854 iso_sched_alloc (unsigned packets, gfp_t mem_flags)
 855 {
 856         struct ehci_iso_sched   *iso_sched;
 857         int                     size = sizeof *iso_sched;
 858
 859         size += packets * sizeof (struct ehci_iso_packet);
 860         iso_sched = kmalloc (size, mem_flags);
 861         if (likely (iso_sched != NULL)) {
 862                 memset(iso_sched, 0, size);
 863                 INIT_LIST_HEAD (&iso_sched->td_list);
 864         }
 865         return iso_sched;
 866 }
 867
 868 static inline void
 869 itd_sched_init (
 870         struct ehci_iso_sched   *iso_sched,
 871         struct ehci_iso_stream  *stream,
 872         struct urb              *urb
 873 )
 874 {
 875         unsigned        i;
 876         dma_addr_t      dma = urb->transfer_dma;
 877
 878         /* how many uframes are needed for these transfers */
 879         iso_sched->span = urb->number_of_packets * stream->interval;
 880
 881         /* figure out per-uframe itd fields that we'll need later
 882          * when we fit new itds into the schedule.
 883          */
 884         for (i = 0; i < urb->number_of_packets; i++) {
 885                 struct ehci_iso_packet  *uframe = &iso_sched->packet [i];
 886                 unsigned                length;
 887                 dma_addr_t              buf;
 888                 u32                     trans;
 889
 890                 length = urb->iso_frame_desc [i].length;
 891                 buf = dma + urb->iso_frame_desc [i].offset;
 892
 893                 trans = EHCI_ISOC_ACTIVE;
 894                 trans |= buf & 0x0fff;
 895                 if (unlikely (((i + 1) == urb->number_of_packets))
 896                                 && !(urb->transfer_flags & URB_NO_INTERRUPT))
 897                         trans |= EHCI_ITD_IOC;
 898                 trans |= length << 16;
 899                 uframe->transaction = cpu_to_le32 (trans);
 900
 901                 /* might need to cross a buffer page within a uframe */
 902                 uframe->bufp = (buf & ~(u64)0x0fff);
 903                 buf += length;
 904                 if (unlikely ((uframe->bufp != (buf & ~(u64)0x0fff))))
 905                         uframe->cross = 1;
 906         }
 907 }
 908
 909 static void
 910 iso_sched_free (
 911         struct ehci_iso_stream  *stream,
 912         struct ehci_iso_sched   *iso_sched
 913 )
 914 {
 915         if (!iso_sched)
 916                 return;
 917         // caller must hold ehci->lock!
 918         list_splice (&iso_sched->td_list, &stream->free_list);
 919         kfree (iso_sched);
 920 }
 921
 922 static int
 923 itd_urb_transaction (
 924         struct ehci_iso_stream  *stream,
 925         struct ehci_hcd         *ehci,
 926         struct urb              *urb,
 927         gfp_t                   mem_flags
 928 )
 929 {
 930         struct ehci_itd         *itd;
 931         dma_addr_t              itd_dma;
 932         int                     i;
 933         unsigned                num_itds;
 934         struct ehci_iso_sched   *sched;
 935         unsigned long           flags;
 936
 937         sched = iso_sched_alloc (urb->number_of_packets, mem_flags);
 938         if (unlikely (sched == NULL))
 939                 return -ENOMEM;
 940
 941         itd_sched_init (sched, stream, urb);
 942
 943         if (urb->interval < 8)
 944                 num_itds = 1 + (sched->span + 7) / 8;
 945         else
 946                 num_itds = urb->number_of_packets;
 947
 948         /* allocate/init ITDs */
 949         spin_lock_irqsave (&ehci->lock, flags);
 950         for (i = 0; i < num_itds; i++) {
 951
 952                 /* free_list.next might be cache-hot ... but maybe
 953                  * the HC caches it too. avoid that issue for now.
 954                  */
 955
 956                 /* prefer previously-allocated itds */
 957                 if (likely (!list_empty(&stream->free_list))) {
 958                         itd = list_entry (stream->free_list.prev,
 959                                          struct ehci_itd, itd_list);
 960                         list_del (&itd->itd_list);
 961                         itd_dma = itd->itd_dma;
 962                 } else
 963                         itd = NULL;
 964
 965                 if (!itd) {
 966                         spin_unlock_irqrestore (&ehci->lock, flags);
 967                         itd = dma_pool_alloc (ehci->itd_pool, mem_flags,
 968                                         &itd_dma);
 969                         spin_lock_irqsave (&ehci->lock, flags);
 970                 }
 971
 972                 if (unlikely (NULL == itd)) {
 973                         iso_sched_free (stream, sched);
 974                         spin_unlock_irqrestore (&ehci->lock, flags);
 975                         return -ENOMEM;
 976                 }
 977                 memset (itd, 0, sizeof *itd);
 978                 itd->itd_dma = itd_dma;
 979                 list_add (&itd->itd_list, &sched->td_list);
 980         }
 981         spin_unlock_irqrestore (&ehci->lock, flags);
 982
 983         /* temporarily store schedule info in hcpriv */
 984         urb->hcpriv = sched;
 985         urb->error_count = 0;
 986         return 0;
 987 }
 988
 989 /*-------------------------------------------------------------------------*/
 990
 991 static inline int
 992 itd_slot_ok (
 993         struct ehci_hcd         *ehci,
 994         u32                     mod,
 995         u32                     uframe,
 996         u8                      usecs,
 997         u32                     period
 998 )
 999 {
1000         uframe %= period;
1001         do {
1002                 /* can't commit more than 80% periodic == 100 usec */
1003                 if (periodic_usecs (ehci, uframe >> 3, uframe & 0x7)
1004                                 > (100 - usecs))
1005                         return 0;
1006
1007                 /* we know urb->interval is 2^N uframes */
1008                 uframe += period;
1009         } while (uframe < mod);
1010         return 1;
1011 }
1012
1013 static inline int
1014 sitd_slot_ok (
1015         struct ehci_hcd         *ehci,
1016         u32                     mod,
1017         struct ehci_iso_stream  *stream,
1018         u32                     uframe,
1019         struct ehci_iso_sched   *sched,
1020         u32                     period_uframes
1021 )
1022 {
1023         u32                     mask, tmp;
1024         u32                     frame, uf;
1025
1026         mask = stream->raw_mask << (uframe & 7);
1027
1028         /* for IN, don't wrap CSPLIT into the next frame */
1029         if (mask & ~0xffff)
1030                 return 0;
1031
1032         /* this multi-pass logic is simple, but performance may
1033          * suffer when the schedule data isn't cached.
1034          */
1035
1036         /* check bandwidth */
1037         uframe %= period_uframes;
1038         do {
1039                 u32             max_used;
1040
1041                 frame = uframe >> 3;
1042                 uf = uframe & 7;
1043
1044                 /* tt must be idle for start(s), any gap, and csplit.
1045                  * assume scheduling slop leaves 10+% for control/bulk.
1046                  */
1047                 if (!tt_no_collision (ehci, period_uframes << 3,
1048                                 stream->udev, frame, mask))
1049                         return 0;
1050
1051                 /* check starts (OUT uses more than one) */
1052                 max_used = 100 - stream->usecs;
1053                 for (tmp = stream->raw_mask & 0xff; tmp; tmp >>= 1, uf++) {
1054                         if (periodic_usecs (ehci, frame, uf) > max_used)
1055                                 return 0;
1056                 }
1057
1058                 /* for IN, check CSPLIT */
1059                 if (stream->c_usecs) {
1060                         max_used = 100 - stream->c_usecs;
1061                         do {
1062                                 tmp = 1 << uf;
1063                                 tmp <<= 8;
1064                                 if ((stream->raw_mask & tmp) == 0)
1065                                         continue;
1066                                 if (periodic_usecs (ehci, frame, uf)
1067                                                 > max_used)
1068                                         return 0;
1069                         } while (++uf < 8);
1070                 }
1071
1072                 /* we know urb->interval is 2^N uframes */
1073                 uframe += period_uframes;
1074         } while (uframe < mod);
1075
1076         stream->splits = cpu_to_le32(stream->raw_mask << (uframe & 7));
1077         return 1;
1078 }
1079
1080 /*
1081  * This scheduler plans almost as far into the future as it has actual
1082  * periodic schedule slots.  (Affected by TUNE_FLS, which defaults to
1083  * "as small as possible" to be cache-friendlier.)  That limits the size
1084  * transfers you can stream reliably; avoid more than 64 msec per urb.
1085  * Also avoid queue depths of less than ehci's worst irq latency (affected
1086  * by the per-urb URB_NO_INTERRUPT hint, the log2_irq_thresh module parameter,
1087  * and other factors); or more than about 230 msec total (for portability,
1088  * given EHCI_TUNE_FLS and the slop).  Or, write a smarter scheduler!
1089  */
1090
1091 #define SCHEDULE_SLOP   10      /* frames */
1092
1093 static int
1094 iso_stream_schedule (
1095         struct ehci_hcd         *ehci,
1096         struct urb              *urb,
1097         struct ehci_iso_stream  *stream
1098 )
1099 {
1100         u32                     now, start, max, period;
1101         int                     status;
1102         unsigned                mod = ehci->periodic_size << 3;
1103         struct ehci_iso_sched   *sched = urb->hcpriv;
1104
1105         if (sched->span > (mod - 8 * SCHEDULE_SLOP)) {
1106                 ehci_dbg (ehci, "iso request %p too long\n", urb);
1107                 status = -EFBIG;
1108                 goto fail;
1109         }
1110
1111         if ((stream->depth + sched->span) > mod) {
1112                 ehci_dbg (ehci, "request %p would overflow (%d+%d>%d)\n",
1113                         urb, stream->depth, sched->span, mod);
1114                 status = -EFBIG;
1115                 goto fail;
1116         }
1117
1118         now = readl (&ehci->regs->frame_index) % mod;
1119
1120         /* when's the last uframe this urb could start? */
1121         max = now + mod;
1122
1123         /* typical case: reuse current schedule. stream is still active,
1124          * and no gaps from host falling behind (irq delays etc)
1125          */
1126         if (likely (!list_empty (&stream->td_list))) {
1127                 start = stream->next_uframe;
1128                 if (start < now)
1129                         start += mod;
1130                 if (likely ((start + sched->span) < max))
1131                         goto ready;
1132                 /* else fell behind; someday, try to reschedule */
1133                 status = -EL2NSYNC;
1134                 goto fail;
1135         }
1136
1137         /* need to schedule; when's the next (u)frame we could start?
1138          * this is bigger than ehci->i_thresh allows; scheduling itself
1139          * isn't free, the slop should handle reasonably slow cpus.  it
1140          * can also help high bandwidth if the dma and irq loads don't
1141          * jump until after the queue is primed.
1142          */
1143         start = SCHEDULE_SLOP * 8 + (now & ~0x07);
1144         start %= mod;
1145         stream->next_uframe = start;
1146
1147         /* NOTE:  assumes URB_ISO_ASAP, to limit complexity/bugs */
1148
1149         period = urb->interval;
1150         if (!stream->highspeed)
1151                 period <<= 3;
1152
1153         /* find a uframe slot with enough bandwidth */
1154         for (; start < (stream->next_uframe + period); start++) {
1155                 int             enough_space;
1156
1157                 /* check schedule: enough space? */
1158                 if (stream->highspeed)
1159                         enough_space = itd_slot_ok (ehci, mod, start,
1160                                         stream->usecs, period);
1161                 else {
1162                         if ((start % 8) >= 6)
1163                                 continue;
1164                         enough_space = sitd_slot_ok (ehci, mod, stream,
1165                                         start, sched, period);
1166                 }
1167
1168                 /* schedule it here if there's enough bandwidth */
1169                 if (enough_space) {
1170                         stream->next_uframe = start % mod;
1171                         goto ready;
1172                 }
1173         }
1174
1175         /* no room in the schedule */
1176         ehci_dbg (ehci, "iso %ssched full %p (now %d max %d)\n",
1177                 list_empty (&stream->td_list) ? "" : "re",
1178                 urb, now, max);
1179         status = -ENOSPC;
1180
1181 fail:
1182         iso_sched_free (stream, sched);
1183         urb->hcpriv = NULL;
1184         return status;
1185
1186 ready:
1187         /* report high speed start in uframes; full speed, in frames */
1188         urb->start_frame = stream->next_uframe;
1189         if (!stream->highspeed)
1190                 urb->start_frame >>= 3;
1191         return 0;
1192 }
1193
1194 /*-------------------------------------------------------------------------*/
1195
1196 static inline void
1197 itd_init (struct ehci_iso_stream *stream, struct ehci_itd *itd)
1198 {
1199         int i;
1200
1201         /* it's been recently zeroed */
1202         itd->hw_next = EHCI_LIST_END;
1203         itd->hw_bufp [0] = stream->buf0;
1204         itd->hw_bufp [1] = stream->buf1;
1205         itd->hw_bufp [2] = stream->buf2;
1206
1207         for (i = 0; i < 8; i++)
1208                 itd->index[i] = -1;
1209
1210         /* All other fields are filled when scheduling */
1211 }
1212
1213 static inline void
1214 itd_patch (
1215         struct ehci_itd         *itd,
1216         struct ehci_iso_sched   *iso_sched,
1217         unsigned                index,
1218         u16                     uframe
1219 )
1220 {
1221         struct ehci_iso_packet  *uf = &iso_sched->packet [index];
1222         unsigned                pg = itd->pg;
1223
1224         // BUG_ON (pg == 6 && uf->cross);
1225
1226         uframe &= 0x07;
1227         itd->index [uframe] = index;
1228
1229         itd->hw_transaction [uframe] = uf->transaction;
1230         itd->hw_transaction [uframe] |= cpu_to_le32 (pg << 12);
1231         itd->hw_bufp [pg] |= cpu_to_le32 (uf->bufp & ~(u32)0);
1232         itd->hw_bufp_hi [pg] |= cpu_to_le32 ((u32)(uf->bufp >> 32));
1233
1234         /* iso_frame_desc[].offset must be strictly increasing */
1235         if (unlikely (uf->cross)) {
1236                 u64     bufp = uf->bufp + 4096;
1237                 itd->pg = ++pg;
1238                 itd->hw_bufp [pg] |= cpu_to_le32 (bufp & ~(u32)0);
1239                 itd->hw_bufp_hi [pg] |= cpu_to_le32 ((u32)(bufp >> 32));
1240         }
1241 }
1242
1243 static inline void
1244 itd_link (struct ehci_hcd *ehci, unsigned frame, struct ehci_itd *itd)
1245 {
1246         /* always prepend ITD/SITD ... only QH tree is order-sensitive */
1247         itd->itd_next = ehci->pshadow [frame];
1248         itd->hw_next = ehci->periodic [frame];
1249         ehci->pshadow [frame].itd = itd;
1250         itd->frame = frame;
1251         wmb ();
1252         ehci->periodic [frame] = cpu_to_le32 (itd->itd_dma) | Q_TYPE_ITD;
1253 }
1254
1255 /* fit urb's itds into the selected schedule slot; activate as needed */
1256 static int
1257 itd_link_urb (
1258         struct ehci_hcd         *ehci,
1259         struct urb              *urb,
1260         unsigned                mod,
1261         struct ehci_iso_stream  *stream
1262 )
1263 {
1264         int                     packet;
1265         unsigned                next_uframe, uframe, frame;
1266         struct ehci_iso_sched   *iso_sched = urb->hcpriv;
1267         struct ehci_itd         *itd;
1268
1269         next_uframe = stream->next_uframe % mod;
1270
1271         if (unlikely (list_empty(&stream->td_list))) {
1272                 ehci_to_hcd(ehci)->self.bandwidth_allocated
1273                                 += stream->bandwidth;
1274                 ehci_vdbg (ehci,
1275                         "schedule devp %s ep%d%s-iso period %d start %d.%d\n",
1276                         urb->dev->devpath, stream->bEndpointAddress & 0x0f,
1277                         (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out",
1278                         urb->interval,
1279                         next_uframe >> 3, next_uframe & 0x7);
1280                 stream->start = jiffies;
1281         }
1282         ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs++;
1283
1284         /* fill iTDs uframe by uframe */
1285         for (packet = 0, itd = NULL; packet < urb->number_of_packets; ) {
1286                 if (itd == NULL) {
1287                         /* ASSERT:  we have all necessary itds */
1288                         // BUG_ON (list_empty (&iso_sched->td_list));
1289
1290                         /* ASSERT:  no itds for this endpoint in this uframe */
1291
1292                         itd = list_entry (iso_sched->td_list.next,
1293                                         struct ehci_itd, itd_list);
1294                         list_move_tail (&itd->itd_list, &stream->td_list);
1295                         itd->stream = iso_stream_get (stream);
1296                         itd->urb = usb_get_urb (urb);
1297                         itd_init (stream, itd);
1298                 }
1299
1300                 uframe = next_uframe & 0x07;
1301                 frame = next_uframe >> 3;
1302
1303                 itd->usecs [uframe] = stream->usecs;
1304                 itd_patch (itd, iso_sched, packet, uframe);
1305
1306                 next_uframe += stream->interval;
1307                 stream->depth += stream->interval;
1308                 next_uframe %= mod;
1309                 packet++;
1310
1311                 /* link completed itds into the schedule */
1312                 if (((next_uframe >> 3) != frame)
1313                                 || packet == urb->number_of_packets) {
1314                         itd_link (ehci, frame % ehci->periodic_size, itd);
1315                         itd = NULL;
1316                 }
1317         }
1318         stream->next_uframe = next_uframe;
1319
1320         /* don't need that schedule data any more */
1321         iso_sched_free (stream, iso_sched);
1322         urb->hcpriv = NULL;
1323
1324         timer_action (ehci, TIMER_IO_WATCHDOG);
1325         if (unlikely (!ehci->periodic_sched++))
1326                 return enable_periodic (ehci);
1327         return 0;
1328 }
1329
1330 #define ISO_ERRS (EHCI_ISOC_BUF_ERR | EHCI_ISOC_BABBLE | EHCI_ISOC_XACTERR)
1331
1332 static unsigned
1333 itd_complete (
1334         struct ehci_hcd *ehci,
1335         struct ehci_itd *itd,
1336         struct pt_regs  *regs
1337 ) {
1338         struct urb                              *urb = itd->urb;
1339         struct usb_iso_packet_descriptor        *desc;
1340         u32                                     t;
1341         unsigned                                uframe;
1342         int                                     urb_index = -1;
1343         struct ehci_iso_stream                  *stream = itd->stream;
1344         struct usb_device                       *dev;
1345
1346         /* for each uframe with a packet */
1347         for (uframe = 0; uframe < 8; uframe++) {
1348                 if (likely (itd->index[uframe] == -1))
1349                         continue;
1350                 urb_index = itd->index[uframe];
1351                 desc = &urb->iso_frame_desc [urb_index];
1352
1353                 t = le32_to_cpup (&itd->hw_transaction [uframe]);
1354                 itd->hw_transaction [uframe] = 0;
1355                 stream->depth -= stream->interval;
1356
1357                 /* report transfer status */
1358                 if (unlikely (t & ISO_ERRS)) {
1359                         urb->error_count++;
1360                         if (t & EHCI_ISOC_BUF_ERR)
1361                                 desc->status = usb_pipein (urb->pipe)
1362                                         ? -ENOSR  /* hc couldn't read */
1363                                         : -ECOMM; /* hc couldn't write */
1364                         else if (t & EHCI_ISOC_BABBLE)
1365                                 desc->status = -EOVERFLOW;
1366                         else /* (t & EHCI_ISOC_XACTERR) */
1367                                 desc->status = -EPROTO;
1368
1369                         /* HC need not update length with this error */
1370                         if (!(t & EHCI_ISOC_BABBLE))
1371                                 desc->actual_length = EHCI_ITD_LENGTH (t);
1372                 } else if (likely ((t & EHCI_ISOC_ACTIVE) == 0)) {
1373                         desc->status = 0;
1374                         desc->actual_length = EHCI_ITD_LENGTH (t);
1375                 }
1376         }
1377
1378         usb_put_urb (urb);
1379         itd->urb = NULL;
1380         itd->stream = NULL;
1381         list_move (&itd->itd_list, &stream->free_list);
1382         iso_stream_put (ehci, stream);
1383
1384         /* handle completion now? */
1385         if (likely ((urb_index + 1) != urb->number_of_packets))
1386                 return 0;
1387
1388         /* ASSERT: it's really the last itd for this urb
1389         list_for_each_entry (itd, &stream->td_list, itd_list)
1390                 BUG_ON (itd->urb == urb);
1391          */
1392
1393         /* give urb back to the driver ... can be out-of-order */
1394         dev = usb_get_dev (urb->dev);
1395         ehci_urb_done (ehci, urb, regs);
1396         urb = NULL;
1397
1398         /* defer stopping schedule; completion can submit */
1399         ehci->periodic_sched--;
1400         if (unlikely (!ehci->periodic_sched))
1401                 (void) disable_periodic (ehci);
1402         ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs--;
1403
1404         if (unlikely (list_empty (&stream->td_list))) {
1405                 ehci_to_hcd(ehci)->self.bandwidth_allocated
1406                                 -= stream->bandwidth;
1407                 ehci_vdbg (ehci,
1408                         "deschedule devp %s ep%d%s-iso\n",
1409                         dev->devpath, stream->bEndpointAddress & 0x0f,
1410                         (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out");
1411         }
1412         iso_stream_put (ehci, stream);
1413         usb_put_dev (dev);
1414
1415         return 1;
1416 }
1417
1418 /*-------------------------------------------------------------------------*/
1419
1420 static int itd_submit (struct ehci_hcd *ehci, struct urb *urb,
1421         gfp_t mem_flags)
1422 {
1423         int                     status = -EINVAL;
1424         unsigned long           flags;
1425         struct ehci_iso_stream  *stream;
1426
1427         /* Get iso_stream head */
1428         stream = iso_stream_find (ehci, urb);
1429         if (unlikely (stream == NULL)) {
1430                 ehci_dbg (ehci, "can't get iso stream\n");
1431                 return -ENOMEM;
1432         }
1433         if (unlikely (urb->interval != stream->interval)) {
1434                 ehci_dbg (ehci, "can't change iso interval %d --> %d\n",
1435                         stream->interval, urb->interval);
1436                 goto done;
1437         }
1438
1439 #ifdef EHCI_URB_TRACE
1440         ehci_dbg (ehci,
1441                 "%s %s urb %p ep%d%s len %d, %d pkts %d uframes [%p]\n",
1442                 __FUNCTION__, urb->dev->devpath, urb,
1443                 usb_pipeendpoint (urb->pipe),
1444                 usb_pipein (urb->pipe) ? "in" : "out",
1445                 urb->transfer_buffer_length,
1446                 urb->number_of_packets, urb->interval,
1447                 stream);
1448 #endif
1449
1450         /* allocate ITDs w/o locking anything */
1451         status = itd_urb_transaction (stream, ehci, urb, mem_flags);
1452         if (unlikely (status < 0)) {
1453                 ehci_dbg (ehci, "can't init itds\n");
1454                 goto done;
1455         }
1456
1457         /* schedule ... need to lock */
1458         spin_lock_irqsave (&ehci->lock, flags);
1459         status = iso_stream_schedule (ehci, urb, stream);
1460         if (likely (status == 0))
1461                 itd_link_urb (ehci, urb, ehci->periodic_size << 3, stream);
1462         spin_unlock_irqrestore (&ehci->lock, flags);
1463
1464 done:
1465         if (unlikely (status < 0))
1466                 iso_stream_put (ehci, stream);
1467         return status;
1468 }
1469
1470 #ifdef CONFIG_USB_EHCI_SPLIT_ISO
1471
1472 /*-------------------------------------------------------------------------*/
1473
1474 /*
1475  * "Split ISO TDs" ... used for USB 1.1 devices going through the
1476  * TTs in USB 2.0 hubs.  These need microframe scheduling.
1477  */
1478
1479 static inline void
1480 sitd_sched_init (
1481         struct ehci_iso_sched   *iso_sched,
1482         struct ehci_iso_stream  *stream,
1483         struct urb              *urb
1484 )
1485 {
1486         unsigned        i;
1487         dma_addr_t      dma = urb->transfer_dma;
1488
1489         /* how many frames are needed for these transfers */
1490         iso_sched->span = urb->number_of_packets * stream->interval;
1491
1492         /* figure out per-frame sitd fields that we'll need later
1493          * when we fit new sitds into the schedule.
1494          */
1495         for (i = 0; i < urb->number_of_packets; i++) {
1496                 struct ehci_iso_packet  *packet = &iso_sched->packet [i];
1497                 unsigned                length;
1498                 dma_addr_t              buf;
1499                 u32                     trans;
1500
1501                 length = urb->iso_frame_desc [i].length & 0x03ff;
1502                 buf = dma + urb->iso_frame_desc [i].offset;
1503
1504                 trans = SITD_STS_ACTIVE;
1505                 if (((i + 1) == urb->number_of_packets)
1506                                 && !(urb->transfer_flags & URB_NO_INTERRUPT))
1507                         trans |= SITD_IOC;
1508                 trans |= length << 16;
1509                 packet->transaction = cpu_to_le32 (trans);
1510
1511                 /* might need to cross a buffer page within a td */
1512                 packet->bufp = buf;
1513                 packet->buf1 = (buf + length) & ~0x0fff;
1514                 if (packet->buf1 != (buf & ~(u64)0x0fff))
1515                         packet->cross = 1;
1516
1517                 /* OUT uses multiple start-splits */
1518                 if (stream->bEndpointAddress & USB_DIR_IN)
1519                         continue;
1520                 length = (length + 187) / 188;
1521                 if (length > 1) /* BEGIN vs ALL */
1522                         length |= 1 << 3;
1523                 packet->buf1 |= length;
1524         }
1525 }
1526
1527 static int
1528 sitd_urb_transaction (
1529         struct ehci_iso_stream  *stream,
1530         struct ehci_hcd         *ehci,
1531         struct urb              *urb,
1532         gfp_t                   mem_flags
1533 )
1534 {
1535         struct ehci_sitd        *sitd;
1536         dma_addr_t              sitd_dma;
1537         int                     i;
1538         struct ehci_iso_sched   *iso_sched;
1539         unsigned long           flags;
1540
1541         iso_sched = iso_sched_alloc (urb->number_of_packets, mem_flags);
1542         if (iso_sched == NULL)
1543                 return -ENOMEM;
1544
1545         sitd_sched_init (iso_sched, stream, urb);
1546
1547         /* allocate/init sITDs */
1548         spin_lock_irqsave (&ehci->lock, flags);
1549         for (i = 0; i < urb->number_of_packets; i++) {
1550
1551                 /* NOTE:  for now, we don't try to handle wraparound cases
1552                  * for IN (using sitd->hw_backpointer, like a FSTN), which
1553                  * means we never need two sitds for full speed packets.
1554                  */
1555
1556                 /* free_list.next might be cache-hot ... but maybe
1557                  * the HC caches it too. avoid that issue for now.
1558                  */
1559
1560                 /* prefer previously-allocated sitds */
1561                 if (!list_empty(&stream->free_list)) {
1562                         sitd = list_entry (stream->free_list.prev,
1563                                          struct ehci_sitd, sitd_list);
1564                         list_del (&sitd->sitd_list);
1565                         sitd_dma = sitd->sitd_dma;
1566                 } else
1567                         sitd = NULL;
1568
1569                 if (!sitd) {
1570                         spin_unlock_irqrestore (&ehci->lock, flags);
1571                         sitd = dma_pool_alloc (ehci->sitd_pool, mem_flags,
1572                                         &sitd_dma);
1573                         spin_lock_irqsave (&ehci->lock, flags);
1574                 }
1575
1576                 if (!sitd) {
1577                         iso_sched_free (stream, iso_sched);
1578                         spin_unlock_irqrestore (&ehci->lock, flags);
1579                         return -ENOMEM;
1580                 }
1581                 memset (sitd, 0, sizeof *sitd);
1582                 sitd->sitd_dma = sitd_dma;
1583                 list_add (&sitd->sitd_list, &iso_sched->td_list);
1584         }
1585
1586         /* temporarily store schedule info in hcpriv */
1587         urb->hcpriv = iso_sched;
1588         urb->error_count = 0;
1589
1590         spin_unlock_irqrestore (&ehci->lock, flags);
1591         return 0;
1592 }
1593
1594 /*-------------------------------------------------------------------------*/
1595
1596 static inline void
1597 sitd_patch (
1598         struct ehci_iso_stream  *stream,
1599         struct ehci_sitd        *sitd,
1600         struct ehci_iso_sched   *iso_sched,
1601         unsigned                index
1602 )
1603 {
1604         struct ehci_iso_packet  *uf = &iso_sched->packet [index];
1605         u64                     bufp = uf->bufp;
1606
1607         sitd->hw_next = EHCI_LIST_END;
1608         sitd->hw_fullspeed_ep = stream->address;
1609         sitd->hw_uframe = stream->splits;
1610         sitd->hw_results = uf->transaction;
1611         sitd->hw_backpointer = EHCI_LIST_END;
1612
1613         bufp = uf->bufp;
1614         sitd->hw_buf [0] = cpu_to_le32 (bufp);
1615         sitd->hw_buf_hi [0] = cpu_to_le32 (bufp >> 32);
1616
1617         sitd->hw_buf [1] = cpu_to_le32 (uf->buf1);
1618         if (uf->cross)
1619                 bufp += 4096;
1620         sitd->hw_buf_hi [1] = cpu_to_le32 (bufp >> 32);
1621         sitd->index = index;
1622 }
1623
1624 static inline void
1625 sitd_link (struct ehci_hcd *ehci, unsigned frame, struct ehci_sitd *sitd)
1626 {
1627         /* note: sitd ordering could matter (CSPLIT then SSPLIT) */
1628         sitd->sitd_next = ehci->pshadow [frame];
1629         sitd->hw_next = ehci->periodic [frame];
1630         ehci->pshadow [frame].sitd = sitd;
1631         sitd->frame = frame;
1632         wmb ();
1633         ehci->periodic [frame] = cpu_to_le32 (sitd->sitd_dma) | Q_TYPE_SITD;
1634 }
1635
1636 /* fit urb's sitds into the selected schedule slot; activate as needed */
1637 static int
1638 sitd_link_urb (
1639         struct ehci_hcd         *ehci,
1640         struct urb              *urb,
1641         unsigned                mod,
1642         struct ehci_iso_stream  *stream
1643 )
1644 {
1645         int                     packet;
1646         unsigned                next_uframe;
1647         struct ehci_iso_sched   *sched = urb->hcpriv;
1648         struct ehci_sitd        *sitd;
1649
1650         next_uframe = stream->next_uframe;
1651
1652         if (list_empty(&stream->td_list)) {
1653                 /* usbfs ignores TT bandwidth */
1654                 ehci_to_hcd(ehci)->self.bandwidth_allocated
1655                                 += stream->bandwidth;
1656                 ehci_vdbg (ehci,
1657                         "sched devp %s ep%d%s-iso [%d] %dms/%04x\n",
1658                         urb->dev->devpath, stream->bEndpointAddress & 0x0f,
1659                         (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out",
1660                         (next_uframe >> 3) % ehci->periodic_size,
1661                         stream->interval, le32_to_cpu (stream->splits));
1662                 stream->start = jiffies;
1663         }
1664         ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs++;
1665
1666         /* fill sITDs frame by frame */
1667         for (packet = 0, sitd = NULL;
1668                         packet < urb->number_of_packets;
1669                         packet++) {
1670
1671                 /* ASSERT:  we have all necessary sitds */
1672                 BUG_ON (list_empty (&sched->td_list));
1673
1674                 /* ASSERT:  no itds for this endpoint in this frame */
1675
1676                 sitd = list_entry (sched->td_list.next,
1677                                 struct ehci_sitd, sitd_list);
1678                 list_move_tail (&sitd->sitd_list, &stream->td_list);
1679                 sitd->stream = iso_stream_get (stream);
1680                 sitd->urb = usb_get_urb (urb);
1681
1682                 sitd_patch (stream, sitd, sched, packet);
1683                 sitd_link (ehci, (next_uframe >> 3) % ehci->periodic_size,
1684                                 sitd);
1685
1686                 next_uframe += stream->interval << 3;
1687                 stream->depth += stream->interval << 3;
1688         }
1689         stream->next_uframe = next_uframe % mod;
1690
1691         /* don't need that schedule data any more */
1692         iso_sched_free (stream, sched);
1693         urb->hcpriv = NULL;
1694
1695         timer_action (ehci, TIMER_IO_WATCHDOG);
1696         if (!ehci->periodic_sched++)
1697                 return enable_periodic (ehci);
1698         return 0;
1699 }
1700
1701 /*-------------------------------------------------------------------------*/
1702
1703 #define SITD_ERRS (SITD_STS_ERR | SITD_STS_DBE | SITD_STS_BABBLE \
1704                                 | SITD_STS_XACT | SITD_STS_MMF)
1705
1706 static unsigned
1707 sitd_complete (
1708         struct ehci_hcd         *ehci,
1709         struct ehci_sitd        *sitd,
1710         struct pt_regs          *regs
1711 ) {
1712         struct urb                              *urb = sitd->urb;
1713         struct usb_iso_packet_descriptor        *desc;
1714         u32                                     t;
1715         int                                     urb_index = -1;
1716         struct ehci_iso_stream                  *stream = sitd->stream;
1717         struct usb_device                       *dev;
1718
1719         urb_index = sitd->index;
1720         desc = &urb->iso_frame_desc [urb_index];
1721         t = le32_to_cpup (&sitd->hw_results);
1722
1723         /* report transfer status */
1724         if (t & SITD_ERRS) {
1725                 urb->error_count++;
1726                 if (t & SITD_STS_DBE)
1727                         desc->status = usb_pipein (urb->pipe)
1728                                 ? -ENOSR  /* hc couldn't read */
1729                                 : -ECOMM; /* hc couldn't write */
1730                 else if (t & SITD_STS_BABBLE)
1731                         desc->status = -EOVERFLOW;
1732                 else /* XACT, MMF, etc */
1733                         desc->status = -EPROTO;
1734         } else {
1735                 desc->status = 0;
1736                 desc->actual_length = desc->length - SITD_LENGTH (t);
1737         }
1738
1739         usb_put_urb (urb);
1740         sitd->urb = NULL;
1741         sitd->stream = NULL;
1742         list_move (&sitd->sitd_list, &stream->free_list);
1743         stream->depth -= stream->interval << 3;
1744         iso_stream_put (ehci, stream);
1745
1746         /* handle completion now? */
1747         if ((urb_index + 1) != urb->number_of_packets)
1748                 return 0;
1749
1750         /* ASSERT: it's really the last sitd for this urb
1751         list_for_each_entry (sitd, &stream->td_list, sitd_list)
1752                 BUG_ON (sitd->urb == urb);
1753          */
1754
1755         /* give urb back to the driver */
1756         dev = usb_get_dev (urb->dev);
1757         ehci_urb_done (ehci, urb, regs);
1758         urb = NULL;
1759
1760         /* defer stopping schedule; completion can submit */
1761         ehci->periodic_sched--;
1762         if (!ehci->periodic_sched)
1763                 (void) disable_periodic (ehci);
1764         ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs--;
1765
1766         if (list_empty (&stream->td_list)) {
1767                 ehci_to_hcd(ehci)->self.bandwidth_allocated
1768                                 -= stream->bandwidth;
1769                 ehci_vdbg (ehci,
1770                         "deschedule devp %s ep%d%s-iso\n",
1771                         dev->devpath, stream->bEndpointAddress & 0x0f,
1772                         (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out");
1773         }
1774         iso_stream_put (ehci, stream);
1775         usb_put_dev (dev);
1776
1777         return 1;
1778 }
1779
1780
1781 static int sitd_submit (struct ehci_hcd *ehci, struct urb *urb,
1782         gfp_t mem_flags)
1783 {
1784         int                     status = -EINVAL;
1785         unsigned long           flags;
1786         struct ehci_iso_stream  *stream;
1787
1788         /* Get iso_stream head */
1789         stream = iso_stream_find (ehci, urb);
1790         if (stream == NULL) {
1791                 ehci_dbg (ehci, "can't get iso stream\n");
1792                 return -ENOMEM;
1793         }
1794         if (urb->interval != stream->interval) {
1795                 ehci_dbg (ehci, "can't change iso interval %d --> %d\n",
1796                         stream->interval, urb->interval);
1797                 goto done;
1798         }
1799
1800 #ifdef EHCI_URB_TRACE
1801         ehci_dbg (ehci,
1802                 "submit %p dev%s ep%d%s-iso len %d\n",
1803                 urb, urb->dev->devpath,
1804                 usb_pipeendpoint (urb->pipe),
1805                 usb_pipein (urb->pipe) ? "in" : "out",
1806                 urb->transfer_buffer_length);
1807 #endif
1808
1809         /* allocate SITDs */
1810         status = sitd_urb_transaction (stream, ehci, urb, mem_flags);
1811         if (status < 0) {
1812                 ehci_dbg (ehci, "can't init sitds\n");
1813                 goto done;
1814         }
1815
1816         /* schedule ... need to lock */
1817         spin_lock_irqsave (&ehci->lock, flags);
1818         status = iso_stream_schedule (ehci, urb, stream);
1819         if (status == 0)
1820                 sitd_link_urb (ehci, urb, ehci->periodic_size << 3, stream);
1821         spin_unlock_irqrestore (&ehci->lock, flags);
1822
1823 done:
1824         if (status < 0)
1825                 iso_stream_put (ehci, stream);
1826         return status;
1827 }
1828
1829 #else
1830
1831 static inline int
1832 sitd_submit (struct ehci_hcd *ehci, struct urb *urb,
1833         unsigned mem_flags)
1834 {
1835         ehci_dbg (ehci, "split iso support is disabled\n");
1836         return -ENOSYS;
1837 }
1838
1839 static inline unsigned
1840 sitd_complete (
1841         struct ehci_hcd         *ehci,
1842         struct ehci_sitd        *sitd,
1843         struct pt_regs          *regs
1844 ) {
1845         ehci_err (ehci, "sitd_complete %p?\n", sitd);
1846         return 0;
1847 }
1848
1849 #endif /* USB_EHCI_SPLIT_ISO */
1850
1851 /*-------------------------------------------------------------------------*/
1852
1853 static void
1854 scan_periodic (struct ehci_hcd *ehci, struct pt_regs *regs)
1855 {
1856         unsigned        frame, clock, now_uframe, mod;
1857         unsigned        modified;
1858
1859         mod = ehci->periodic_size << 3;
1860
1861         /*
1862          * When running, scan from last scan point up to "now"
1863          * else clean up by scanning everything that's left.
1864          * Touches as few pages as possible:  cache-friendly.
1865          */
1866         now_uframe = ehci->next_uframe;
1867         if (HC_IS_RUNNING (ehci_to_hcd(ehci)->state))
1868                 clock = readl (&ehci->regs->frame_index);
1869         else
1870                 clock = now_uframe + mod - 1;
1871         clock %= mod;
1872
1873         for (;;) {
1874                 union ehci_shadow       q, *q_p;
1875                 __le32                  type, *hw_p;
1876                 unsigned                uframes;
1877
1878                 /* don't scan past the live uframe */
1879                 frame = now_uframe >> 3;
1880                 if (frame == (clock >> 3))
1881                         uframes = now_uframe & 0x07;
1882                 else {
1883                         /* safe to scan the whole frame at once */
1884                         now_uframe |= 0x07;
1885                         uframes = 8;
1886                 }
1887
1888 restart:
1889                 /* scan each element in frame's queue for completions */
1890                 q_p = &ehci->pshadow [frame];
1891                 hw_p = &ehci->periodic [frame];
1892                 q.ptr = q_p->ptr;
1893                 type = Q_NEXT_TYPE (*hw_p);
1894                 modified = 0;
1895
1896                 while (q.ptr != NULL) {
1897                         unsigned                uf;
1898                         union ehci_shadow       temp;
1899                         int                     live;
1900
1901                         live = HC_IS_RUNNING (ehci_to_hcd(ehci)->state);
1902                         switch (type) {
1903                         case Q_TYPE_QH:
1904                                 /* handle any completions */
1905                                 temp.qh = qh_get (q.qh);
1906                                 type = Q_NEXT_TYPE (q.qh->hw_next);
1907                                 q = q.qh->qh_next;
1908                                 modified = qh_completions (ehci, temp.qh, regs);
1909                                 if (unlikely (list_empty (&temp.qh->qtd_list)))
1910                                         intr_deschedule (ehci, temp.qh);
1911                                 qh_put (temp.qh);
1912                                 break;
1913                         case Q_TYPE_FSTN:
1914                                 /* for "save place" FSTNs, look at QH entries
1915                                  * in the previous frame for completions.
1916                                  */
1917                                 if (q.fstn->hw_prev != EHCI_LIST_END) {
1918                                         dbg ("ignoring completions from FSTNs");
1919                                 }
1920                                 type = Q_NEXT_TYPE (q.fstn->hw_next);
1921                                 q = q.fstn->fstn_next;
1922                                 break;
1923                         case Q_TYPE_ITD:
1924                                 /* skip itds for later in the frame */
1925                                 rmb ();
1926                                 for (uf = live ? uframes : 8; uf < 8; uf++) {
1927                                         if (0 == (q.itd->hw_transaction [uf]
1928                                                         & ITD_ACTIVE))
1929                                                 continue;
1930                                         q_p = &q.itd->itd_next;
1931                                         hw_p = &q.itd->hw_next;
1932                                         type = Q_NEXT_TYPE (q.itd->hw_next);
1933                                         q = *q_p;
1934                                         break;
1935                                 }
1936                                 if (uf != 8)
1937                                         break;
1938
1939                                 /* this one's ready ... HC won't cache the
1940                                  * pointer for much longer, if at all.
1941                                  */
1942                                 *q_p = q.itd->itd_next;
1943                                 *hw_p = q.itd->hw_next;
1944                                 type = Q_NEXT_TYPE (q.itd->hw_next);
1945                                 wmb();
1946                                 modified = itd_complete (ehci, q.itd, regs);
1947                                 q = *q_p;
1948                                 break;
1949                         case Q_TYPE_SITD:
1950                                 if ((q.sitd->hw_results & SITD_ACTIVE)
1951                                                 && live) {
1952                                         q_p = &q.sitd->sitd_next;
1953                                         hw_p = &q.sitd->hw_next;
1954                                         type = Q_NEXT_TYPE (q.sitd->hw_next);
1955                                         q = *q_p;
1956                                         break;
1957                                 }
1958                                 *q_p = q.sitd->sitd_next;
1959                                 *hw_p = q.sitd->hw_next;
1960                                 type = Q_NEXT_TYPE (q.sitd->hw_next);
1961                                 wmb();
1962                                 modified = sitd_complete (ehci, q.sitd, regs);
1963                                 q = *q_p;
1964                                 break;
1965                         default:
1966                                 dbg ("corrupt type %d frame %d shadow %p",
1967                                         type, frame, q.ptr);
1968                                 // BUG ();
1969                                 q.ptr = NULL;
1970                         }
1971
1972                         /* assume completion callbacks modify the queue */
1973                         if (unlikely (modified))
1974                                 goto restart;
1975                 }
1976
1977                 /* stop when we catch up to the HC */
1978
1979                 // FIXME:  this assumes we won't get lapped when
1980                 // latencies climb; that should be rare, but...
1981                 // detect it, and just go all the way around.
1982                 // FLR might help detect this case, so long as latencies
1983                 // don't exceed periodic_size msec (default 1.024 sec).
1984
1985                 // FIXME:  likewise assumes HC doesn't halt mid-scan
1986
1987                 if (now_uframe == clock) {
1988                         unsigned        now;
1989
1990                         if (!HC_IS_RUNNING (ehci_to_hcd(ehci)->state))
1991                                 break;
1992                         ehci->next_uframe = now_uframe;
1993                         now = readl (&ehci->regs->frame_index) % mod;
1994                         if (now_uframe == now)
1995                                 break;
1996
1997                         /* rescan the rest of this frame, then ... */
1998                         clock = now;
1999                 } else {
2000                         now_uframe++;
2001                         now_uframe %= mod;
2002                 }
2003         }
2004 }