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         unsigned                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 (unsigned mem_flags)
 638 {
 639         struct ehci_iso_stream *stream;
 640
 641         stream = kcalloc(1, 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
 704                 addr = dev->ttport << 24;
 705                 if (!ehci_is_TDI(ehci)
 706                                 || (dev->tt->hub !=
 707                                         ehci_to_hcd(ehci)->self.root_hub))
 708                         addr |= dev->tt->hub->devnum << 16;
 709                 addr |= epnum << 8;
 710                 addr |= dev->devnum;
 711                 stream->usecs = HS_USECS_ISO (maxp);
 712                 if (is_input) {
 713                         u32     tmp;
 714
 715                         addr |= 1 << 31;
 716                         stream->c_usecs = stream->usecs;
 717                         stream->usecs = HS_USECS_ISO (1);
 718                         stream->raw_mask = 1;
 719
 720                         /* pessimistic c-mask */
 721                         tmp = usb_calc_bus_time (USB_SPEED_FULL, 1, 0, maxp)
 722                                         / (125 * 1000);
 723                         stream->raw_mask |= 3 << (tmp + 9);
 724                 } else
 725                         stream->raw_mask = smask_out [maxp / 188];
 726                 bandwidth = stream->usecs + stream->c_usecs;
 727                 bandwidth /= 1 << (interval + 2);
 728
 729                 /* stream->splits gets created from raw_mask later */
 730                 stream->address = cpu_to_le32 (addr);
 731         }
 732         stream->bandwidth = bandwidth;
 733
 734         stream->udev = dev;
 735
 736         stream->bEndpointAddress = is_input | epnum;
 737         stream->interval = interval;
 738         stream->maxp = maxp;
 739 }
 740
 741 static void
 742 iso_stream_put(struct ehci_hcd *ehci, struct ehci_iso_stream *stream)
 743 {
 744         stream->refcount--;
 745
 746         /* free whenever just a dev->ep reference remains.
 747          * not like a QH -- no persistent state (toggle, halt)
 748          */
 749         if (stream->refcount == 1) {
 750                 int             is_in;
 751
 752                 // BUG_ON (!list_empty(&stream->td_list));
 753
 754                 while (!list_empty (&stream->free_list)) {
 755                         struct list_head        *entry;
 756
 757                         entry = stream->free_list.next;
 758                         list_del (entry);
 759
 760                         /* knows about ITD vs SITD */
 761                         if (stream->highspeed) {
 762                                 struct ehci_itd         *itd;
 763
 764                                 itd = list_entry (entry, struct ehci_itd,
 765                                                 itd_list);
 766                                 dma_pool_free (ehci->itd_pool, itd,
 767                                                 itd->itd_dma);
 768                         } else {
 769                                 struct ehci_sitd        *sitd;
 770
 771                                 sitd = list_entry (entry, struct ehci_sitd,
 772                                                 sitd_list);
 773                                 dma_pool_free (ehci->sitd_pool, sitd,
 774                                                 sitd->sitd_dma);
 775                         }
 776                 }
 777
 778                 is_in = (stream->bEndpointAddress & USB_DIR_IN) ? 0x10 : 0;
 779                 stream->bEndpointAddress &= 0x0f;
 780                 stream->ep->hcpriv = NULL;
 781
 782                 if (stream->rescheduled) {
 783                         ehci_info (ehci, "ep%d%s-iso rescheduled "
 784                                 "%lu times in %lu seconds\n",
 785                                 stream->bEndpointAddress, is_in ? "in" : "out",
 786                                 stream->rescheduled,
 787                                 ((jiffies - stream->start)/HZ)
 788                                 );
 789                 }
 790
 791                 kfree(stream);
 792         }
 793 }
 794
 795 static inline struct ehci_iso_stream *
 796 iso_stream_get (struct ehci_iso_stream *stream)
 797 {
 798         if (likely (stream != NULL))
 799                 stream->refcount++;
 800         return stream;
 801 }
 802
 803 static struct ehci_iso_stream *
 804 iso_stream_find (struct ehci_hcd *ehci, struct urb *urb)
 805 {
 806         unsigned                epnum;
 807         struct ehci_iso_stream  *stream;
 808         struct usb_host_endpoint *ep;
 809         unsigned long           flags;
 810
 811         epnum = usb_pipeendpoint (urb->pipe);
 812         if (usb_pipein(urb->pipe))
 813                 ep = urb->dev->ep_in[epnum];
 814         else
 815                 ep = urb->dev->ep_out[epnum];
 816
 817         spin_lock_irqsave (&ehci->lock, flags);
 818         stream = ep->hcpriv;
 819
 820         if (unlikely (stream == NULL)) {
 821                 stream = iso_stream_alloc(GFP_ATOMIC);
 822                 if (likely (stream != NULL)) {
 823                         /* dev->ep owns the initial refcount */
 824                         ep->hcpriv = stream;
 825                         stream->ep = ep;
 826                         iso_stream_init(ehci, stream, urb->dev, urb->pipe,
 827                                         urb->interval);
 828                 }
 829
 830         /* if dev->ep [epnum] is a QH, info1.maxpacket is nonzero */
 831         } else if (unlikely (stream->hw_info1 != 0)) {
 832                 ehci_dbg (ehci, "dev %s ep%d%s, not iso??\n",
 833                         urb->dev->devpath, epnum,
 834                         usb_pipein(urb->pipe) ? "in" : "out");
 835                 stream = NULL;
 836         }
 837
 838         /* caller guarantees an eventual matching iso_stream_put */
 839         stream = iso_stream_get (stream);
 840
 841         spin_unlock_irqrestore (&ehci->lock, flags);
 842         return stream;
 843 }
 844
 845 /*-------------------------------------------------------------------------*/
 846
 847 /* ehci_iso_sched ops can be ITD-only or SITD-only */
 848
 849 static struct ehci_iso_sched *
 850 iso_sched_alloc (unsigned packets, unsigned mem_flags)
 851 {
 852         struct ehci_iso_sched   *iso_sched;
 853         int                     size = sizeof *iso_sched;
 854
 855         size += packets * sizeof (struct ehci_iso_packet);
 856         iso_sched = kmalloc (size, mem_flags);
 857         if (likely (iso_sched != NULL)) {
 858                 memset(iso_sched, 0, size);
 859                 INIT_LIST_HEAD (&iso_sched->td_list);
 860         }
 861         return iso_sched;
 862 }
 863
 864 static inline void
 865 itd_sched_init (
 866         struct ehci_iso_sched   *iso_sched,
 867         struct ehci_iso_stream  *stream,
 868         struct urb              *urb
 869 )
 870 {
 871         unsigned        i;
 872         dma_addr_t      dma = urb->transfer_dma;
 873
 874         /* how many uframes are needed for these transfers */
 875         iso_sched->span = urb->number_of_packets * stream->interval;
 876
 877         /* figure out per-uframe itd fields that we'll need later
 878          * when we fit new itds into the schedule.
 879          */
 880         for (i = 0; i < urb->number_of_packets; i++) {
 881                 struct ehci_iso_packet  *uframe = &iso_sched->packet [i];
 882                 unsigned                length;
 883                 dma_addr_t              buf;
 884                 u32                     trans;
 885
 886                 length = urb->iso_frame_desc [i].length;
 887                 buf = dma + urb->iso_frame_desc [i].offset;
 888
 889                 trans = EHCI_ISOC_ACTIVE;
 890                 trans |= buf & 0x0fff;
 891                 if (unlikely (((i + 1) == urb->number_of_packets))
 892                                 && !(urb->transfer_flags & URB_NO_INTERRUPT))
 893                         trans |= EHCI_ITD_IOC;
 894                 trans |= length << 16;
 895                 uframe->transaction = cpu_to_le32 (trans);
 896
 897                 /* might need to cross a buffer page within a uframe */
 898                 uframe->bufp = (buf & ~(u64)0x0fff);
 899                 buf += length;
 900                 if (unlikely ((uframe->bufp != (buf & ~(u64)0x0fff))))
 901                         uframe->cross = 1;
 902         }
 903 }
 904
 905 static void
 906 iso_sched_free (
 907         struct ehci_iso_stream  *stream,
 908         struct ehci_iso_sched   *iso_sched
 909 )
 910 {
 911         if (!iso_sched)
 912                 return;
 913         // caller must hold ehci->lock!
 914         list_splice (&iso_sched->td_list, &stream->free_list);
 915         kfree (iso_sched);
 916 }
 917
 918 static int
 919 itd_urb_transaction (
 920         struct ehci_iso_stream  *stream,
 921         struct ehci_hcd         *ehci,
 922         struct urb              *urb,
 923         unsigned                mem_flags
 924 )
 925 {
 926         struct ehci_itd         *itd;
 927         dma_addr_t              itd_dma;
 928         int                     i;
 929         unsigned                num_itds;
 930         struct ehci_iso_sched   *sched;
 931         unsigned long           flags;
 932
 933         sched = iso_sched_alloc (urb->number_of_packets, mem_flags);
 934         if (unlikely (sched == NULL))
 935                 return -ENOMEM;
 936
 937         itd_sched_init (sched, stream, urb);
 938
 939         if (urb->interval < 8)
 940                 num_itds = 1 + (sched->span + 7) / 8;
 941         else
 942                 num_itds = urb->number_of_packets;
 943
 944         /* allocate/init ITDs */
 945         spin_lock_irqsave (&ehci->lock, flags);
 946         for (i = 0; i < num_itds; i++) {
 947
 948                 /* free_list.next might be cache-hot ... but maybe
 949                  * the HC caches it too. avoid that issue for now.
 950                  */
 951
 952                 /* prefer previously-allocated itds */
 953                 if (likely (!list_empty(&stream->free_list))) {
 954                         itd = list_entry (stream->free_list.prev,
 955                                          struct ehci_itd, itd_list);
 956                         list_del (&itd->itd_list);
 957                         itd_dma = itd->itd_dma;
 958                 } else
 959                         itd = NULL;
 960
 961                 if (!itd) {
 962                         spin_unlock_irqrestore (&ehci->lock, flags);
 963                         itd = dma_pool_alloc (ehci->itd_pool, mem_flags,
 964                                         &itd_dma);
 965                         spin_lock_irqsave (&ehci->lock, flags);
 966                 }
 967
 968                 if (unlikely (NULL == itd)) {
 969                         iso_sched_free (stream, sched);
 970                         spin_unlock_irqrestore (&ehci->lock, flags);
 971                         return -ENOMEM;
 972                 }
 973                 memset (itd, 0, sizeof *itd);
 974                 itd->itd_dma = itd_dma;
 975                 list_add (&itd->itd_list, &sched->td_list);
 976         }
 977         spin_unlock_irqrestore (&ehci->lock, flags);
 978
 979         /* temporarily store schedule info in hcpriv */
 980         urb->hcpriv = sched;
 981         urb->error_count = 0;
 982         return 0;
 983 }
 984
 985 /*-------------------------------------------------------------------------*/
 986
 987 static inline int
 988 itd_slot_ok (
 989         struct ehci_hcd         *ehci,
 990         u32                     mod,
 991         u32                     uframe,
 992         u8                      usecs,
 993         u32                     period
 994 )
 995 {
 996         uframe %= period;
 997         do {
 998                 /* can't commit more than 80% periodic == 100 usec */
 999                 if (periodic_usecs (ehci, uframe >> 3, uframe & 0x7)
1000                                 > (100 - usecs))
1001                         return 0;
1002
1003                 /* we know urb->interval is 2^N uframes */
1004                 uframe += period;
1005         } while (uframe < mod);
1006         return 1;
1007 }
1008
1009 static inline int
1010 sitd_slot_ok (
1011         struct ehci_hcd         *ehci,
1012         u32                     mod,
1013         struct ehci_iso_stream  *stream,
1014         u32                     uframe,
1015         struct ehci_iso_sched   *sched,
1016         u32                     period_uframes
1017 )
1018 {
1019         u32                     mask, tmp;
1020         u32                     frame, uf;
1021
1022         mask = stream->raw_mask << (uframe & 7);
1023
1024         /* for IN, don't wrap CSPLIT into the next frame */
1025         if (mask & ~0xffff)
1026                 return 0;
1027
1028         /* this multi-pass logic is simple, but performance may
1029          * suffer when the schedule data isn't cached.
1030          */
1031
1032         /* check bandwidth */
1033         uframe %= period_uframes;
1034         do {
1035                 u32             max_used;
1036
1037                 frame = uframe >> 3;
1038                 uf = uframe & 7;
1039
1040                 /* tt must be idle for start(s), any gap, and csplit.
1041                  * assume scheduling slop leaves 10+% for control/bulk.
1042                  */
1043                 if (!tt_no_collision (ehci, period_uframes << 3,
1044                                 stream->udev, frame, mask))
1045                         return 0;
1046
1047                 /* check starts (OUT uses more than one) */
1048                 max_used = 100 - stream->usecs;
1049                 for (tmp = stream->raw_mask & 0xff; tmp; tmp >>= 1, uf++) {
1050                         if (periodic_usecs (ehci, frame, uf) > max_used)
1051                                 return 0;
1052                 }
1053
1054                 /* for IN, check CSPLIT */
1055                 if (stream->c_usecs) {
1056                         max_used = 100 - stream->c_usecs;
1057                         do {
1058                                 tmp = 1 << uf;
1059                                 tmp <<= 8;
1060                                 if ((stream->raw_mask & tmp) == 0)
1061                                         continue;
1062                                 if (periodic_usecs (ehci, frame, uf)
1063                                                 > max_used)
1064                                         return 0;
1065                         } while (++uf < 8);
1066                 }
1067
1068                 /* we know urb->interval is 2^N uframes */
1069                 uframe += period_uframes;
1070         } while (uframe < mod);
1071
1072         stream->splits = cpu_to_le32(stream->raw_mask << (uframe & 7));
1073         return 1;
1074 }
1075
1076 /*
1077  * This scheduler plans almost as far into the future as it has actual
1078  * periodic schedule slots.  (Affected by TUNE_FLS, which defaults to
1079  * "as small as possible" to be cache-friendlier.)  That limits the size
1080  * transfers you can stream reliably; avoid more than 64 msec per urb.
1081  * Also avoid queue depths of less than ehci's worst irq latency (affected
1082  * by the per-urb URB_NO_INTERRUPT hint, the log2_irq_thresh module parameter,
1083  * and other factors); or more than about 230 msec total (for portability,
1084  * given EHCI_TUNE_FLS and the slop).  Or, write a smarter scheduler!
1085  */
1086
1087 #define SCHEDULE_SLOP   10      /* frames */
1088
1089 static int
1090 iso_stream_schedule (
1091         struct ehci_hcd         *ehci,
1092         struct urb              *urb,
1093         struct ehci_iso_stream  *stream
1094 )
1095 {
1096         u32                     now, start, max, period;
1097         int                     status;
1098         unsigned                mod = ehci->periodic_size << 3;
1099         struct ehci_iso_sched   *sched = urb->hcpriv;
1100
1101         if (sched->span > (mod - 8 * SCHEDULE_SLOP)) {
1102                 ehci_dbg (ehci, "iso request %p too long\n", urb);
1103                 status = -EFBIG;
1104                 goto fail;
1105         }
1106
1107         if ((stream->depth + sched->span) > mod) {
1108                 ehci_dbg (ehci, "request %p would overflow (%d+%d>%d)\n",
1109                         urb, stream->depth, sched->span, mod);
1110                 status = -EFBIG;
1111                 goto fail;
1112         }
1113
1114         now = readl (&ehci->regs->frame_index) % mod;
1115
1116         /* when's the last uframe this urb could start? */
1117         max = now + mod;
1118
1119         /* typical case: reuse current schedule. stream is still active,
1120          * and no gaps from host falling behind (irq delays etc)
1121          */
1122         if (likely (!list_empty (&stream->td_list))) {
1123                 start = stream->next_uframe;
1124                 if (start < now)
1125                         start += mod;
1126                 if (likely ((start + sched->span) < max))
1127                         goto ready;
1128                 /* else fell behind; someday, try to reschedule */
1129                 status = -EL2NSYNC;
1130                 goto fail;
1131         }
1132
1133         /* need to schedule; when's the next (u)frame we could start?
1134          * this is bigger than ehci->i_thresh allows; scheduling itself
1135          * isn't free, the slop should handle reasonably slow cpus.  it
1136          * can also help high bandwidth if the dma and irq loads don't
1137          * jump until after the queue is primed.
1138          */
1139         start = SCHEDULE_SLOP * 8 + (now & ~0x07);
1140         start %= mod;
1141         stream->next_uframe = start;
1142
1143         /* NOTE:  assumes URB_ISO_ASAP, to limit complexity/bugs */
1144
1145         period = urb->interval;
1146         if (!stream->highspeed)
1147                 period <<= 3;
1148
1149         /* find a uframe slot with enough bandwidth */
1150         for (; start < (stream->next_uframe + period); start++) {
1151                 int             enough_space;
1152
1153                 /* check schedule: enough space? */
1154                 if (stream->highspeed)
1155                         enough_space = itd_slot_ok (ehci, mod, start,
1156                                         stream->usecs, period);
1157                 else {
1158                         if ((start % 8) >= 6)
1159                                 continue;
1160                         enough_space = sitd_slot_ok (ehci, mod, stream,
1161                                         start, sched, period);
1162                 }
1163
1164                 /* schedule it here if there's enough bandwidth */
1165                 if (enough_space) {
1166                         stream->next_uframe = start % mod;
1167                         goto ready;
1168                 }
1169         }
1170
1171         /* no room in the schedule */
1172         ehci_dbg (ehci, "iso %ssched full %p (now %d max %d)\n",
1173                 list_empty (&stream->td_list) ? "" : "re",
1174                 urb, now, max);
1175         status = -ENOSPC;
1176
1177 fail:
1178         iso_sched_free (stream, sched);
1179         urb->hcpriv = NULL;
1180         return status;
1181
1182 ready:
1183         /* report high speed start in uframes; full speed, in frames */
1184         urb->start_frame = stream->next_uframe;
1185         if (!stream->highspeed)
1186                 urb->start_frame >>= 3;
1187         return 0;
1188 }
1189
1190 /*-------------------------------------------------------------------------*/
1191
1192 static inline void
1193 itd_init (struct ehci_iso_stream *stream, struct ehci_itd *itd)
1194 {
1195         int i;
1196
1197         /* it's been recently zeroed */
1198         itd->hw_next = EHCI_LIST_END;
1199         itd->hw_bufp [0] = stream->buf0;
1200         itd->hw_bufp [1] = stream->buf1;
1201         itd->hw_bufp [2] = stream->buf2;
1202
1203         for (i = 0; i < 8; i++)
1204                 itd->index[i] = -1;
1205
1206         /* All other fields are filled when scheduling */
1207 }
1208
1209 static inline void
1210 itd_patch (
1211         struct ehci_itd         *itd,
1212         struct ehci_iso_sched   *iso_sched,
1213         unsigned                index,
1214         u16                     uframe
1215 )
1216 {
1217         struct ehci_iso_packet  *uf = &iso_sched->packet [index];
1218         unsigned                pg = itd->pg;
1219
1220         // BUG_ON (pg == 6 && uf->cross);
1221
1222         uframe &= 0x07;
1223         itd->index [uframe] = index;
1224
1225         itd->hw_transaction [uframe] = uf->transaction;
1226         itd->hw_transaction [uframe] |= cpu_to_le32 (pg << 12);
1227         itd->hw_bufp [pg] |= cpu_to_le32 (uf->bufp & ~(u32)0);
1228         itd->hw_bufp_hi [pg] |= cpu_to_le32 ((u32)(uf->bufp >> 32));
1229
1230         /* iso_frame_desc[].offset must be strictly increasing */
1231         if (unlikely (uf->cross)) {
1232                 u64     bufp = uf->bufp + 4096;
1233                 itd->pg = ++pg;
1234                 itd->hw_bufp [pg] |= cpu_to_le32 (bufp & ~(u32)0);
1235                 itd->hw_bufp_hi [pg] |= cpu_to_le32 ((u32)(bufp >> 32));
1236         }
1237 }
1238
1239 static inline void
1240 itd_link (struct ehci_hcd *ehci, unsigned frame, struct ehci_itd *itd)
1241 {
1242         /* always prepend ITD/SITD ... only QH tree is order-sensitive */
1243         itd->itd_next = ehci->pshadow [frame];
1244         itd->hw_next = ehci->periodic [frame];
1245         ehci->pshadow [frame].itd = itd;
1246         itd->frame = frame;
1247         wmb ();
1248         ehci->periodic [frame] = cpu_to_le32 (itd->itd_dma) | Q_TYPE_ITD;
1249 }
1250
1251 /* fit urb's itds into the selected schedule slot; activate as needed */
1252 static int
1253 itd_link_urb (
1254         struct ehci_hcd         *ehci,
1255         struct urb              *urb,
1256         unsigned                mod,
1257         struct ehci_iso_stream  *stream
1258 )
1259 {
1260         int                     packet;
1261         unsigned                next_uframe, uframe, frame;
1262         struct ehci_iso_sched   *iso_sched = urb->hcpriv;
1263         struct ehci_itd         *itd;
1264
1265         next_uframe = stream->next_uframe % mod;
1266
1267         if (unlikely (list_empty(&stream->td_list))) {
1268                 ehci_to_hcd(ehci)->self.bandwidth_allocated
1269                                 += stream->bandwidth;
1270                 ehci_vdbg (ehci,
1271                         "schedule devp %s ep%d%s-iso period %d start %d.%d\n",
1272                         urb->dev->devpath, stream->bEndpointAddress & 0x0f,
1273                         (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out",
1274                         urb->interval,
1275                         next_uframe >> 3, next_uframe & 0x7);
1276                 stream->start = jiffies;
1277         }
1278         ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs++;
1279
1280         /* fill iTDs uframe by uframe */
1281         for (packet = 0, itd = NULL; packet < urb->number_of_packets; ) {
1282                 if (itd == NULL) {
1283                         /* ASSERT:  we have all necessary itds */
1284                         // BUG_ON (list_empty (&iso_sched->td_list));
1285
1286                         /* ASSERT:  no itds for this endpoint in this uframe */
1287
1288                         itd = list_entry (iso_sched->td_list.next,
1289                                         struct ehci_itd, itd_list);
1290                         list_move_tail (&itd->itd_list, &stream->td_list);
1291                         itd->stream = iso_stream_get (stream);
1292                         itd->urb = usb_get_urb (urb);
1293                         itd_init (stream, itd);
1294                 }
1295
1296                 uframe = next_uframe & 0x07;
1297                 frame = next_uframe >> 3;
1298
1299                 itd->usecs [uframe] = stream->usecs;
1300                 itd_patch (itd, iso_sched, packet, uframe);
1301
1302                 next_uframe += stream->interval;
1303                 stream->depth += stream->interval;
1304                 next_uframe %= mod;
1305                 packet++;
1306
1307                 /* link completed itds into the schedule */
1308                 if (((next_uframe >> 3) != frame)
1309                                 || packet == urb->number_of_packets) {
1310                         itd_link (ehci, frame % ehci->periodic_size, itd);
1311                         itd = NULL;
1312                 }
1313         }
1314         stream->next_uframe = next_uframe;
1315
1316         /* don't need that schedule data any more */
1317         iso_sched_free (stream, iso_sched);
1318         urb->hcpriv = NULL;
1319
1320         timer_action (ehci, TIMER_IO_WATCHDOG);
1321         if (unlikely (!ehci->periodic_sched++))
1322                 return enable_periodic (ehci);
1323         return 0;
1324 }
1325
1326 #define ISO_ERRS (EHCI_ISOC_BUF_ERR | EHCI_ISOC_BABBLE | EHCI_ISOC_XACTERR)
1327
1328 static unsigned
1329 itd_complete (
1330         struct ehci_hcd *ehci,
1331         struct ehci_itd *itd,
1332         struct pt_regs  *regs
1333 ) {
1334         struct urb                              *urb = itd->urb;
1335         struct usb_iso_packet_descriptor        *desc;
1336         u32                                     t;
1337         unsigned                                uframe;
1338         int                                     urb_index = -1;
1339         struct ehci_iso_stream                  *stream = itd->stream;
1340         struct usb_device                       *dev;
1341
1342         /* for each uframe with a packet */
1343         for (uframe = 0; uframe < 8; uframe++) {
1344                 if (likely (itd->index[uframe] == -1))
1345                         continue;
1346                 urb_index = itd->index[uframe];
1347                 desc = &urb->iso_frame_desc [urb_index];
1348
1349                 t = le32_to_cpup (&itd->hw_transaction [uframe]);
1350                 itd->hw_transaction [uframe] = 0;
1351                 stream->depth -= stream->interval;
1352
1353                 /* report transfer status */
1354                 if (unlikely (t & ISO_ERRS)) {
1355                         urb->error_count++;
1356                         if (t & EHCI_ISOC_BUF_ERR)
1357                                 desc->status = usb_pipein (urb->pipe)
1358                                         ? -ENOSR  /* hc couldn't read */
1359                                         : -ECOMM; /* hc couldn't write */
1360                         else if (t & EHCI_ISOC_BABBLE)
1361                                 desc->status = -EOVERFLOW;
1362                         else /* (t & EHCI_ISOC_XACTERR) */
1363                                 desc->status = -EPROTO;
1364
1365                         /* HC need not update length with this error */
1366                         if (!(t & EHCI_ISOC_BABBLE))
1367                                 desc->actual_length = EHCI_ITD_LENGTH (t);
1368                 } else if (likely ((t & EHCI_ISOC_ACTIVE) == 0)) {
1369                         desc->status = 0;
1370                         desc->actual_length = EHCI_ITD_LENGTH (t);
1371                 }
1372         }
1373
1374         usb_put_urb (urb);
1375         itd->urb = NULL;
1376         itd->stream = NULL;
1377         list_move (&itd->itd_list, &stream->free_list);
1378         iso_stream_put (ehci, stream);
1379
1380         /* handle completion now? */
1381         if (likely ((urb_index + 1) != urb->number_of_packets))
1382                 return 0;
1383
1384         /* ASSERT: it's really the last itd for this urb
1385         list_for_each_entry (itd, &stream->td_list, itd_list)
1386                 BUG_ON (itd->urb == urb);
1387          */
1388
1389         /* give urb back to the driver ... can be out-of-order */
1390         dev = usb_get_dev (urb->dev);
1391         ehci_urb_done (ehci, urb, regs);
1392         urb = NULL;
1393
1394         /* defer stopping schedule; completion can submit */
1395         ehci->periodic_sched--;
1396         if (unlikely (!ehci->periodic_sched))
1397                 (void) disable_periodic (ehci);
1398         ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs--;
1399
1400         if (unlikely (list_empty (&stream->td_list))) {
1401                 ehci_to_hcd(ehci)->self.bandwidth_allocated
1402                                 -= stream->bandwidth;
1403                 ehci_vdbg (ehci,
1404                         "deschedule devp %s ep%d%s-iso\n",
1405                         dev->devpath, stream->bEndpointAddress & 0x0f,
1406                         (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out");
1407         }
1408         iso_stream_put (ehci, stream);
1409         usb_put_dev (dev);
1410
1411         return 1;
1412 }
1413
1414 /*-------------------------------------------------------------------------*/
1415
1416 static int itd_submit (struct ehci_hcd *ehci, struct urb *urb,
1417         unsigned mem_flags)
1418 {
1419         int                     status = -EINVAL;
1420         unsigned long           flags;
1421         struct ehci_iso_stream  *stream;
1422
1423         /* Get iso_stream head */
1424         stream = iso_stream_find (ehci, urb);
1425         if (unlikely (stream == NULL)) {
1426                 ehci_dbg (ehci, "can't get iso stream\n");
1427                 return -ENOMEM;
1428         }
1429         if (unlikely (urb->interval != stream->interval)) {
1430                 ehci_dbg (ehci, "can't change iso interval %d --> %d\n",
1431                         stream->interval, urb->interval);
1432                 goto done;
1433         }
1434
1435 #ifdef EHCI_URB_TRACE
1436         ehci_dbg (ehci,
1437                 "%s %s urb %p ep%d%s len %d, %d pkts %d uframes [%p]\n",
1438                 __FUNCTION__, urb->dev->devpath, urb,
1439                 usb_pipeendpoint (urb->pipe),
1440                 usb_pipein (urb->pipe) ? "in" : "out",
1441                 urb->transfer_buffer_length,
1442                 urb->number_of_packets, urb->interval,
1443                 stream);
1444 #endif
1445
1446         /* allocate ITDs w/o locking anything */
1447         status = itd_urb_transaction (stream, ehci, urb, mem_flags);
1448         if (unlikely (status < 0)) {
1449                 ehci_dbg (ehci, "can't init itds\n");
1450                 goto done;
1451         }
1452
1453         /* schedule ... need to lock */
1454         spin_lock_irqsave (&ehci->lock, flags);
1455         status = iso_stream_schedule (ehci, urb, stream);
1456         if (likely (status == 0))
1457                 itd_link_urb (ehci, urb, ehci->periodic_size << 3, stream);
1458         spin_unlock_irqrestore (&ehci->lock, flags);
1459
1460 done:
1461         if (unlikely (status < 0))
1462                 iso_stream_put (ehci, stream);
1463         return status;
1464 }
1465
1466 #ifdef CONFIG_USB_EHCI_SPLIT_ISO
1467
1468 /*-------------------------------------------------------------------------*/
1469
1470 /*
1471  * "Split ISO TDs" ... used for USB 1.1 devices going through the
1472  * TTs in USB 2.0 hubs.  These need microframe scheduling.
1473  */
1474
1475 static inline void
1476 sitd_sched_init (
1477         struct ehci_iso_sched   *iso_sched,
1478         struct ehci_iso_stream  *stream,
1479         struct urb              *urb
1480 )
1481 {
1482         unsigned        i;
1483         dma_addr_t      dma = urb->transfer_dma;
1484
1485         /* how many frames are needed for these transfers */
1486         iso_sched->span = urb->number_of_packets * stream->interval;
1487
1488         /* figure out per-frame sitd fields that we'll need later
1489          * when we fit new sitds into the schedule.
1490          */
1491         for (i = 0; i < urb->number_of_packets; i++) {
1492                 struct ehci_iso_packet  *packet = &iso_sched->packet [i];
1493                 unsigned                length;
1494                 dma_addr_t              buf;
1495                 u32                     trans;
1496
1497                 length = urb->iso_frame_desc [i].length & 0x03ff;
1498                 buf = dma + urb->iso_frame_desc [i].offset;
1499
1500                 trans = SITD_STS_ACTIVE;
1501                 if (((i + 1) == urb->number_of_packets)
1502                                 && !(urb->transfer_flags & URB_NO_INTERRUPT))
1503                         trans |= SITD_IOC;
1504                 trans |= length << 16;
1505                 packet->transaction = cpu_to_le32 (trans);
1506
1507                 /* might need to cross a buffer page within a td */
1508                 packet->bufp = buf;
1509                 packet->buf1 = (buf + length) & ~0x0fff;
1510                 if (packet->buf1 != (buf & ~(u64)0x0fff))
1511                         packet->cross = 1;
1512
1513                 /* OUT uses multiple start-splits */
1514                 if (stream->bEndpointAddress & USB_DIR_IN)
1515                         continue;
1516                 length = (length + 187) / 188;
1517                 if (length > 1) /* BEGIN vs ALL */
1518                         length |= 1 << 3;
1519                 packet->buf1 |= length;
1520         }
1521 }
1522
1523 static int
1524 sitd_urb_transaction (
1525         struct ehci_iso_stream  *stream,
1526         struct ehci_hcd         *ehci,
1527         struct urb              *urb,
1528         unsigned                mem_flags
1529 )
1530 {
1531         struct ehci_sitd        *sitd;
1532         dma_addr_t              sitd_dma;
1533         int                     i;
1534         struct ehci_iso_sched   *iso_sched;
1535         unsigned long           flags;
1536
1537         iso_sched = iso_sched_alloc (urb->number_of_packets, mem_flags);
1538         if (iso_sched == NULL)
1539                 return -ENOMEM;
1540
1541         sitd_sched_init (iso_sched, stream, urb);
1542
1543         /* allocate/init sITDs */
1544         spin_lock_irqsave (&ehci->lock, flags);
1545         for (i = 0; i < urb->number_of_packets; i++) {
1546
1547                 /* NOTE:  for now, we don't try to handle wraparound cases
1548                  * for IN (using sitd->hw_backpointer, like a FSTN), which
1549                  * means we never need two sitds for full speed packets.
1550                  */
1551
1552                 /* free_list.next might be cache-hot ... but maybe
1553                  * the HC caches it too. avoid that issue for now.
1554                  */
1555
1556                 /* prefer previously-allocated sitds */
1557                 if (!list_empty(&stream->free_list)) {
1558                         sitd = list_entry (stream->free_list.prev,
1559                                          struct ehci_sitd, sitd_list);
1560                         list_del (&sitd->sitd_list);
1561                         sitd_dma = sitd->sitd_dma;
1562                 } else
1563                         sitd = NULL;
1564
1565                 if (!sitd) {
1566                         spin_unlock_irqrestore (&ehci->lock, flags);
1567                         sitd = dma_pool_alloc (ehci->sitd_pool, mem_flags,
1568                                         &sitd_dma);
1569                         spin_lock_irqsave (&ehci->lock, flags);
1570                 }
1571
1572                 if (!sitd) {
1573                         iso_sched_free (stream, iso_sched);
1574                         spin_unlock_irqrestore (&ehci->lock, flags);
1575                         return -ENOMEM;
1576                 }
1577                 memset (sitd, 0, sizeof *sitd);
1578                 sitd->sitd_dma = sitd_dma;
1579                 list_add (&sitd->sitd_list, &iso_sched->td_list);
1580         }
1581
1582         /* temporarily store schedule info in hcpriv */
1583         urb->hcpriv = iso_sched;
1584         urb->error_count = 0;
1585
1586         spin_unlock_irqrestore (&ehci->lock, flags);
1587         return 0;
1588 }
1589
1590 /*-------------------------------------------------------------------------*/
1591
1592 static inline void
1593 sitd_patch (
1594         struct ehci_iso_stream  *stream,
1595         struct ehci_sitd        *sitd,
1596         struct ehci_iso_sched   *iso_sched,
1597         unsigned                index
1598 )
1599 {
1600         struct ehci_iso_packet  *uf = &iso_sched->packet [index];
1601         u64                     bufp = uf->bufp;
1602
1603         sitd->hw_next = EHCI_LIST_END;
1604         sitd->hw_fullspeed_ep = stream->address;
1605         sitd->hw_uframe = stream->splits;
1606         sitd->hw_results = uf->transaction;
1607         sitd->hw_backpointer = EHCI_LIST_END;
1608
1609         bufp = uf->bufp;
1610         sitd->hw_buf [0] = cpu_to_le32 (bufp);
1611         sitd->hw_buf_hi [0] = cpu_to_le32 (bufp >> 32);
1612
1613         sitd->hw_buf [1] = cpu_to_le32 (uf->buf1);
1614         if (uf->cross)
1615                 bufp += 4096;
1616         sitd->hw_buf_hi [1] = cpu_to_le32 (bufp >> 32);
1617         sitd->index = index;
1618 }
1619
1620 static inline void
1621 sitd_link (struct ehci_hcd *ehci, unsigned frame, struct ehci_sitd *sitd)
1622 {
1623         /* note: sitd ordering could matter (CSPLIT then SSPLIT) */
1624         sitd->sitd_next = ehci->pshadow [frame];
1625         sitd->hw_next = ehci->periodic [frame];
1626         ehci->pshadow [frame].sitd = sitd;
1627         sitd->frame = frame;
1628         wmb ();
1629         ehci->periodic [frame] = cpu_to_le32 (sitd->sitd_dma) | Q_TYPE_SITD;
1630 }
1631
1632 /* fit urb's sitds into the selected schedule slot; activate as needed */
1633 static int
1634 sitd_link_urb (
1635         struct ehci_hcd         *ehci,
1636         struct urb              *urb,
1637         unsigned                mod,
1638         struct ehci_iso_stream  *stream
1639 )
1640 {
1641         int                     packet;
1642         unsigned                next_uframe;
1643         struct ehci_iso_sched   *sched = urb->hcpriv;
1644         struct ehci_sitd        *sitd;
1645
1646         next_uframe = stream->next_uframe;
1647
1648         if (list_empty(&stream->td_list)) {
1649                 /* usbfs ignores TT bandwidth */
1650                 ehci_to_hcd(ehci)->self.bandwidth_allocated
1651                                 += stream->bandwidth;
1652                 ehci_vdbg (ehci,
1653                         "sched devp %s ep%d%s-iso [%d] %dms/%04x\n",
1654                         urb->dev->devpath, stream->bEndpointAddress & 0x0f,
1655                         (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out",
1656                         (next_uframe >> 3) % ehci->periodic_size,
1657                         stream->interval, le32_to_cpu (stream->splits));
1658                 stream->start = jiffies;
1659         }
1660         ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs++;
1661
1662         /* fill sITDs frame by frame */
1663         for (packet = 0, sitd = NULL;
1664                         packet < urb->number_of_packets;
1665                         packet++) {
1666
1667                 /* ASSERT:  we have all necessary sitds */
1668                 BUG_ON (list_empty (&sched->td_list));
1669
1670                 /* ASSERT:  no itds for this endpoint in this frame */
1671
1672                 sitd = list_entry (sched->td_list.next,
1673                                 struct ehci_sitd, sitd_list);
1674                 list_move_tail (&sitd->sitd_list, &stream->td_list);
1675                 sitd->stream = iso_stream_get (stream);
1676                 sitd->urb = usb_get_urb (urb);
1677
1678                 sitd_patch (stream, sitd, sched, packet);
1679                 sitd_link (ehci, (next_uframe >> 3) % ehci->periodic_size,
1680                                 sitd);
1681
1682                 next_uframe += stream->interval << 3;
1683                 stream->depth += stream->interval << 3;
1684         }
1685         stream->next_uframe = next_uframe % mod;
1686
1687         /* don't need that schedule data any more */
1688         iso_sched_free (stream, sched);
1689         urb->hcpriv = NULL;
1690
1691         timer_action (ehci, TIMER_IO_WATCHDOG);
1692         if (!ehci->periodic_sched++)
1693                 return enable_periodic (ehci);
1694         return 0;
1695 }
1696
1697 /*-------------------------------------------------------------------------*/
1698
1699 #define SITD_ERRS (SITD_STS_ERR | SITD_STS_DBE | SITD_STS_BABBLE \
1700                                 | SITD_STS_XACT | SITD_STS_MMF)
1701
1702 static unsigned
1703 sitd_complete (
1704         struct ehci_hcd         *ehci,
1705         struct ehci_sitd        *sitd,
1706         struct pt_regs          *regs
1707 ) {
1708         struct urb                              *urb = sitd->urb;
1709         struct usb_iso_packet_descriptor        *desc;
1710         u32                                     t;
1711         int                                     urb_index = -1;
1712         struct ehci_iso_stream                  *stream = sitd->stream;
1713         struct usb_device                       *dev;
1714
1715         urb_index = sitd->index;
1716         desc = &urb->iso_frame_desc [urb_index];
1717         t = le32_to_cpup (&sitd->hw_results);
1718
1719         /* report transfer status */
1720         if (t & SITD_ERRS) {
1721                 urb->error_count++;
1722                 if (t & SITD_STS_DBE)
1723                         desc->status = usb_pipein (urb->pipe)
1724                                 ? -ENOSR  /* hc couldn't read */
1725                                 : -ECOMM; /* hc couldn't write */
1726                 else if (t & SITD_STS_BABBLE)
1727                         desc->status = -EOVERFLOW;
1728                 else /* XACT, MMF, etc */
1729                         desc->status = -EPROTO;
1730         } else {
1731                 desc->status = 0;
1732                 desc->actual_length = desc->length - SITD_LENGTH (t);
1733         }
1734
1735         usb_put_urb (urb);
1736         sitd->urb = NULL;
1737         sitd->stream = NULL;
1738         list_move (&sitd->sitd_list, &stream->free_list);
1739         stream->depth -= stream->interval << 3;
1740         iso_stream_put (ehci, stream);
1741
1742         /* handle completion now? */
1743         if ((urb_index + 1) != urb->number_of_packets)
1744                 return 0;
1745
1746         /* ASSERT: it's really the last sitd for this urb
1747         list_for_each_entry (sitd, &stream->td_list, sitd_list)
1748                 BUG_ON (sitd->urb == urb);
1749          */
1750
1751         /* give urb back to the driver */
1752         dev = usb_get_dev (urb->dev);
1753         ehci_urb_done (ehci, urb, regs);
1754         urb = NULL;
1755
1756         /* defer stopping schedule; completion can submit */
1757         ehci->periodic_sched--;
1758         if (!ehci->periodic_sched)
1759                 (void) disable_periodic (ehci);
1760         ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs--;
1761
1762         if (list_empty (&stream->td_list)) {
1763                 ehci_to_hcd(ehci)->self.bandwidth_allocated
1764                                 -= stream->bandwidth;
1765                 ehci_vdbg (ehci,
1766                         "deschedule devp %s ep%d%s-iso\n",
1767                         dev->devpath, stream->bEndpointAddress & 0x0f,
1768                         (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out");
1769         }
1770         iso_stream_put (ehci, stream);
1771         usb_put_dev (dev);
1772
1773         return 1;
1774 }
1775
1776
1777 static int sitd_submit (struct ehci_hcd *ehci, struct urb *urb,
1778         unsigned mem_flags)
1779 {
1780         int                     status = -EINVAL;
1781         unsigned long           flags;
1782         struct ehci_iso_stream  *stream;
1783
1784         /* Get iso_stream head */
1785         stream = iso_stream_find (ehci, urb);
1786         if (stream == NULL) {
1787                 ehci_dbg (ehci, "can't get iso stream\n");
1788                 return -ENOMEM;
1789         }
1790         if (urb->interval != stream->interval) {
1791                 ehci_dbg (ehci, "can't change iso interval %d --> %d\n",
1792                         stream->interval, urb->interval);
1793                 goto done;
1794         }
1795
1796 #ifdef EHCI_URB_TRACE
1797         ehci_dbg (ehci,
1798                 "submit %p dev%s ep%d%s-iso len %d\n",
1799                 urb, urb->dev->devpath,
1800                 usb_pipeendpoint (urb->pipe),
1801                 usb_pipein (urb->pipe) ? "in" : "out",
1802                 urb->transfer_buffer_length);
1803 #endif
1804
1805         /* allocate SITDs */
1806         status = sitd_urb_transaction (stream, ehci, urb, mem_flags);
1807         if (status < 0) {
1808                 ehci_dbg (ehci, "can't init sitds\n");
1809                 goto done;
1810         }
1811
1812         /* schedule ... need to lock */
1813         spin_lock_irqsave (&ehci->lock, flags);
1814         status = iso_stream_schedule (ehci, urb, stream);
1815         if (status == 0)
1816                 sitd_link_urb (ehci, urb, ehci->periodic_size << 3, stream);
1817         spin_unlock_irqrestore (&ehci->lock, flags);
1818
1819 done:
1820         if (status < 0)
1821                 iso_stream_put (ehci, stream);
1822         return status;
1823 }
1824
1825 #else
1826
1827 static inline int
1828 sitd_submit (struct ehci_hcd *ehci, struct urb *urb,
1829         unsigned mem_flags)
1830 {
1831         ehci_dbg (ehci, "split iso support is disabled\n");
1832         return -ENOSYS;
1833 }
1834
1835 static inline unsigned
1836 sitd_complete (
1837         struct ehci_hcd         *ehci,
1838         struct ehci_sitd        *sitd,
1839         struct pt_regs          *regs
1840 ) {
1841         ehci_err (ehci, "sitd_complete %p?\n", sitd);
1842         return 0;
1843 }
1844
1845 #endif /* USB_EHCI_SPLIT_ISO */
1846
1847 /*-------------------------------------------------------------------------*/
1848
1849 static void
1850 scan_periodic (struct ehci_hcd *ehci, struct pt_regs *regs)
1851 {
1852         unsigned        frame, clock, now_uframe, mod;
1853         unsigned        modified;
1854
1855         mod = ehci->periodic_size << 3;
1856
1857         /*
1858          * When running, scan from last scan point up to "now"
1859          * else clean up by scanning everything that's left.
1860          * Touches as few pages as possible:  cache-friendly.
1861          */
1862         now_uframe = ehci->next_uframe;
1863         if (HC_IS_RUNNING (ehci_to_hcd(ehci)->state))
1864                 clock = readl (&ehci->regs->frame_index);
1865         else
1866                 clock = now_uframe + mod - 1;
1867         clock %= mod;
1868
1869         for (;;) {
1870                 union ehci_shadow       q, *q_p;
1871                 __le32                  type, *hw_p;
1872                 unsigned                uframes;
1873
1874                 /* don't scan past the live uframe */
1875                 frame = now_uframe >> 3;
1876                 if (frame == (clock >> 3))
1877                         uframes = now_uframe & 0x07;
1878                 else {
1879                         /* safe to scan the whole frame at once */
1880                         now_uframe |= 0x07;
1881                         uframes = 8;
1882                 }
1883
1884 restart:
1885                 /* scan each element in frame's queue for completions */
1886                 q_p = &ehci->pshadow [frame];
1887                 hw_p = &ehci->periodic [frame];
1888                 q.ptr = q_p->ptr;
1889                 type = Q_NEXT_TYPE (*hw_p);
1890                 modified = 0;
1891
1892                 while (q.ptr != NULL) {
1893                         unsigned                uf;
1894                         union ehci_shadow       temp;
1895                         int                     live;
1896
1897                         live = HC_IS_RUNNING (ehci_to_hcd(ehci)->state);
1898                         switch (type) {
1899                         case Q_TYPE_QH:
1900                                 /* handle any completions */
1901                                 temp.qh = qh_get (q.qh);
1902                                 type = Q_NEXT_TYPE (q.qh->hw_next);
1903                                 q = q.qh->qh_next;
1904                                 modified = qh_completions (ehci, temp.qh, regs);
1905                                 if (unlikely (list_empty (&temp.qh->qtd_list)))
1906                                         intr_deschedule (ehci, temp.qh);
1907                                 qh_put (temp.qh);
1908                                 break;
1909                         case Q_TYPE_FSTN:
1910                                 /* for "save place" FSTNs, look at QH entries
1911                                  * in the previous frame for completions.
1912                                  */
1913                                 if (q.fstn->hw_prev != EHCI_LIST_END) {
1914                                         dbg ("ignoring completions from FSTNs");
1915                                 }
1916                                 type = Q_NEXT_TYPE (q.fstn->hw_next);
1917                                 q = q.fstn->fstn_next;
1918                                 break;
1919                         case Q_TYPE_ITD:
1920                                 /* skip itds for later in the frame */
1921                                 rmb ();
1922                                 for (uf = live ? uframes : 8; uf < 8; uf++) {
1923                                         if (0 == (q.itd->hw_transaction [uf]
1924                                                         & ITD_ACTIVE))
1925                                                 continue;
1926                                         q_p = &q.itd->itd_next;
1927                                         hw_p = &q.itd->hw_next;
1928                                         type = Q_NEXT_TYPE (q.itd->hw_next);
1929                                         q = *q_p;
1930                                         break;
1931                                 }
1932                                 if (uf != 8)
1933                                         break;
1934
1935                                 /* this one's ready ... HC won't cache the
1936                                  * pointer for much longer, if at all.
1937                                  */
1938                                 *q_p = q.itd->itd_next;
1939                                 *hw_p = q.itd->hw_next;
1940                                 type = Q_NEXT_TYPE (q.itd->hw_next);
1941                                 wmb();
1942                                 modified = itd_complete (ehci, q.itd, regs);
1943                                 q = *q_p;
1944                                 break;
1945                         case Q_TYPE_SITD:
1946                                 if ((q.sitd->hw_results & SITD_ACTIVE)
1947                                                 && live) {
1948                                         q_p = &q.sitd->sitd_next;
1949                                         hw_p = &q.sitd->hw_next;
1950                                         type = Q_NEXT_TYPE (q.sitd->hw_next);
1951                                         q = *q_p;
1952                                         break;
1953                                 }
1954                                 *q_p = q.sitd->sitd_next;
1955                                 *hw_p = q.sitd->hw_next;
1956                                 type = Q_NEXT_TYPE (q.sitd->hw_next);
1957                                 wmb();
1958                                 modified = sitd_complete (ehci, q.sitd, regs);
1959                                 q = *q_p;
1960                                 break;
1961                         default:
1962                                 dbg ("corrupt type %d frame %d shadow %p",
1963                                         type, frame, q.ptr);
1964                                 // BUG ();
1965                                 q.ptr = NULL;
1966                         }
1967
1968                         /* assume completion callbacks modify the queue */
1969                         if (unlikely (modified))
1970                                 goto restart;
1971                 }
1972
1973                 /* stop when we catch up to the HC */
1974
1975                 // FIXME:  this assumes we won't get lapped when
1976                 // latencies climb; that should be rare, but...
1977                 // detect it, and just go all the way around.
1978                 // FLR might help detect this case, so long as latencies
1979                 // don't exceed periodic_size msec (default 1.024 sec).
1980
1981                 // FIXME:  likewise assumes HC doesn't halt mid-scan
1982
1983                 if (now_uframe == clock) {
1984                         unsigned        now;
1985
1986                         if (!HC_IS_RUNNING (ehci_to_hcd(ehci)->state))
1987                                 break;
1988                         ehci->next_uframe = now_uframe;
1989                         now = readl (&ehci->regs->frame_index) % mod;
1990                         if (now_uframe == now)
1991                                 break;
1992
1993                         /* rescan the rest of this frame, then ... */
1994                         clock = now;
1995                 } else {
1996                         now_uframe++;
1997                         now_uframe %= mod;
1998                 }
1999         }
2000 }