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  * periodic_next_shadow - return "next" pointer on shadow list
  41  * @periodic: host pointer to qh/itd/sitd
  42  * @tag: hardware tag for type of this record
  43  */
  44 static union ehci_shadow *
  45 periodic_next_shadow(struct ehci_hcd *ehci, union ehci_shadow *periodic,
  46                 __hc32 tag)
  47 {
  48         switch (hc32_to_cpu(ehci, tag)) {
  49         case Q_TYPE_QH:
  50                 return &periodic->qh->qh_next;
  51         case Q_TYPE_FSTN:
  52                 return &periodic->fstn->fstn_next;
  53         case Q_TYPE_ITD:
  54                 return &periodic->itd->itd_next;
  55         // case Q_TYPE_SITD:
  56         default:
  57                 return &periodic->sitd->sitd_next;
  58         }
  59 }
  60
  61 static __hc32 *
  62 shadow_next_periodic(struct ehci_hcd *ehci, union ehci_shadow *periodic,
  63                 __hc32 tag)
  64 {
  65         switch (hc32_to_cpu(ehci, tag)) {
  66         /* our ehci_shadow.qh is actually software part */
  67         case Q_TYPE_QH:
  68                 return &periodic->qh->hw->hw_next;
  69         /* others are hw parts */
  70         default:
  71                 return periodic->hw_next;
  72         }
  73 }
  74
  75 /* caller must hold ehci->lock */
  76 static void periodic_unlink (struct ehci_hcd *ehci, unsigned frame, void *ptr)
  77 {
  78         union ehci_shadow       *prev_p = &ehci->pshadow[frame];
  79         __hc32                  *hw_p = &ehci->periodic[frame];
  80         union ehci_shadow       here = *prev_p;
  81
  82         /* find predecessor of "ptr"; hw and shadow lists are in sync */
  83         while (here.ptr && here.ptr != ptr) {
  84                 prev_p = periodic_next_shadow(ehci, prev_p,
  85                                 Q_NEXT_TYPE(ehci, *hw_p));
  86                 hw_p = shadow_next_periodic(ehci, &here,
  87                                 Q_NEXT_TYPE(ehci, *hw_p));
  88                 here = *prev_p;
  89         }
  90         /* an interrupt entry (at list end) could have been shared */
  91         if (!here.ptr)
  92                 return;
  93
  94         /* update shadow and hardware lists ... the old "next" pointers
  95          * from ptr may still be in use, the caller updates them.
  96          */
  97         *prev_p = *periodic_next_shadow(ehci, &here,
  98                         Q_NEXT_TYPE(ehci, *hw_p));
  99
 100         if (!ehci->use_dummy_qh ||
 101             *shadow_next_periodic(ehci, &here, Q_NEXT_TYPE(ehci, *hw_p))
 102                         != EHCI_LIST_END(ehci))
 103                 *hw_p = *shadow_next_periodic(ehci, &here,
 104                                 Q_NEXT_TYPE(ehci, *hw_p));
 105         else
 106                 *hw_p = ehci->dummy->qh_dma;
 107 }
 108
 109 /* how many of the uframe's 125 usecs are allocated? */
 110 static unsigned short
 111 periodic_usecs (struct ehci_hcd *ehci, unsigned frame, unsigned uframe)
 112 {
 113         __hc32                  *hw_p = &ehci->periodic [frame];
 114         union ehci_shadow       *q = &ehci->pshadow [frame];
 115         unsigned                usecs = 0;
 116         struct ehci_qh_hw       *hw;
 117
 118         while (q->ptr) {
 119                 switch (hc32_to_cpu(ehci, Q_NEXT_TYPE(ehci, *hw_p))) {
 120                 case Q_TYPE_QH:
 121                         hw = q->qh->hw;
 122                         /* is it in the S-mask? */
 123                         if (hw->hw_info2 & cpu_to_hc32(ehci, 1 << uframe))
 124                                 usecs += q->qh->usecs;
 125                         /* ... or C-mask? */
 126                         if (hw->hw_info2 & cpu_to_hc32(ehci,
 127                                         1 << (8 + uframe)))
 128                                 usecs += q->qh->c_usecs;
 129                         hw_p = &hw->hw_next;
 130                         q = &q->qh->qh_next;
 131                         break;
 132                 // case Q_TYPE_FSTN:
 133                 default:
 134                         /* for "save place" FSTNs, count the relevant INTR
 135                          * bandwidth from the previous frame
 136                          */
 137                         if (q->fstn->hw_prev != EHCI_LIST_END(ehci)) {
 138                                 ehci_dbg (ehci, "ignoring FSTN cost ...\n");
 139                         }
 140                         hw_p = &q->fstn->hw_next;
 141                         q = &q->fstn->fstn_next;
 142                         break;
 143                 case Q_TYPE_ITD:
 144                         if (q->itd->hw_transaction[uframe])
 145                                 usecs += q->itd->stream->usecs;
 146                         hw_p = &q->itd->hw_next;
 147                         q = &q->itd->itd_next;
 148                         break;
 149                 case Q_TYPE_SITD:
 150                         /* is it in the S-mask?  (count SPLIT, DATA) */
 151                         if (q->sitd->hw_uframe & cpu_to_hc32(ehci,
 152                                         1 << uframe)) {
 153                                 if (q->sitd->hw_fullspeed_ep &
 154                                                 cpu_to_hc32(ehci, 1<<31))
 155                                         usecs += q->sitd->stream->usecs;
 156                                 else    /* worst case for OUT start-split */
 157                                         usecs += HS_USECS_ISO (188);
 158                         }
 159
 160                         /* ... C-mask?  (count CSPLIT, DATA) */
 161                         if (q->sitd->hw_uframe &
 162                                         cpu_to_hc32(ehci, 1 << (8 + uframe))) {
 163                                 /* worst case for IN complete-split */
 164                                 usecs += q->sitd->stream->c_usecs;
 165                         }
 166
 167                         hw_p = &q->sitd->hw_next;
 168                         q = &q->sitd->sitd_next;
 169                         break;
 170                 }
 171         }
 172 #ifdef  DEBUG
 173         if (usecs > ehci->uframe_periodic_max)
 174                 ehci_err (ehci, "uframe %d sched overrun: %d usecs\n",
 175                         frame * 8 + uframe, usecs);
 176 #endif
 177         return usecs;
 178 }
 179
 180 /*-------------------------------------------------------------------------*/
 181
 182 static int same_tt (struct usb_device *dev1, struct usb_device *dev2)
 183 {
 184         if (!dev1->tt || !dev2->tt)
 185                 return 0;
 186         if (dev1->tt != dev2->tt)
 187                 return 0;
 188         if (dev1->tt->multi)
 189                 return dev1->ttport == dev2->ttport;
 190         else
 191                 return 1;
 192 }
 193
 194 #ifdef CONFIG_USB_EHCI_TT_NEWSCHED
 195
 196 /* Which uframe does the low/fullspeed transfer start in?
 197  *
 198  * The parameter is the mask of ssplits in "H-frame" terms
 199  * and this returns the transfer start uframe in "B-frame" terms,
 200  * which allows both to match, e.g. a ssplit in "H-frame" uframe 0
 201  * will cause a transfer in "B-frame" uframe 0.  "B-frames" lag
 202  * "H-frames" by 1 uframe.  See the EHCI spec sec 4.5 and figure 4.7.
 203  */
 204 static inline unsigned char tt_start_uframe(struct ehci_hcd *ehci, __hc32 mask)
 205 {
 206         unsigned char smask = QH_SMASK & hc32_to_cpu(ehci, mask);
 207         if (!smask) {
 208                 ehci_err(ehci, "invalid empty smask!\n");
 209                 /* uframe 7 can't have bw so this will indicate failure */
 210                 return 7;
 211         }
 212         return ffs(smask) - 1;
 213 }
 214
 215 static const unsigned char
 216 max_tt_usecs[] = { 125, 125, 125, 125, 125, 125, 30, 0 };
 217
 218 /* carryover low/fullspeed bandwidth that crosses uframe boundries */
 219 static inline void carryover_tt_bandwidth(unsigned short tt_usecs[8])
 220 {
 221         int i;
 222         for (i=0; i<7; i++) {
 223                 if (max_tt_usecs[i] < tt_usecs[i]) {
 224                         tt_usecs[i+1] += tt_usecs[i] - max_tt_usecs[i];
 225                         tt_usecs[i] = max_tt_usecs[i];
 226                 }
 227         }
 228 }
 229
 230 /* How many of the tt's periodic downstream 1000 usecs are allocated?
 231  *
 232  * While this measures the bandwidth in terms of usecs/uframe,
 233  * the low/fullspeed bus has no notion of uframes, so any particular
 234  * low/fullspeed transfer can "carry over" from one uframe to the next,
 235  * since the TT just performs downstream transfers in sequence.
 236  *
 237  * For example two separate 100 usec transfers can start in the same uframe,
 238  * and the second one would "carry over" 75 usecs into the next uframe.
 239  */
 240 static void
 241 periodic_tt_usecs (
 242         struct ehci_hcd *ehci,
 243         struct usb_device *dev,
 244         unsigned frame,
 245         unsigned short tt_usecs[8]
 246 )
 247 {
 248         __hc32                  *hw_p = &ehci->periodic [frame];
 249         union ehci_shadow       *q = &ehci->pshadow [frame];
 250         unsigned char           uf;
 251
 252         memset(tt_usecs, 0, 16);
 253
 254         while (q->ptr) {
 255                 switch (hc32_to_cpu(ehci, Q_NEXT_TYPE(ehci, *hw_p))) {
 256                 case Q_TYPE_ITD:
 257                         hw_p = &q->itd->hw_next;
 258                         q = &q->itd->itd_next;
 259                         continue;
 260                 case Q_TYPE_QH:
 261                         if (same_tt(dev, q->qh->dev)) {
 262                                 uf = tt_start_uframe(ehci, q->qh->hw->hw_info2);
 263                                 tt_usecs[uf] += q->qh->tt_usecs;
 264                         }
 265                         hw_p = &q->qh->hw->hw_next;
 266                         q = &q->qh->qh_next;
 267                         continue;
 268                 case Q_TYPE_SITD:
 269                         if (same_tt(dev, q->sitd->urb->dev)) {
 270                                 uf = tt_start_uframe(ehci, q->sitd->hw_uframe);
 271                                 tt_usecs[uf] += q->sitd->stream->tt_usecs;
 272                         }
 273                         hw_p = &q->sitd->hw_next;
 274                         q = &q->sitd->sitd_next;
 275                         continue;
 276                 // case Q_TYPE_FSTN:
 277                 default:
 278                         ehci_dbg(ehci, "ignoring periodic frame %d FSTN\n",
 279                                         frame);
 280                         hw_p = &q->fstn->hw_next;
 281                         q = &q->fstn->fstn_next;
 282                 }
 283         }
 284
 285         carryover_tt_bandwidth(tt_usecs);
 286
 287         if (max_tt_usecs[7] < tt_usecs[7])
 288                 ehci_err(ehci, "frame %d tt sched overrun: %d usecs\n",
 289                         frame, tt_usecs[7] - max_tt_usecs[7]);
 290 }
 291
 292 /*
 293  * Return true if the device's tt's downstream bus is available for a
 294  * periodic transfer of the specified length (usecs), starting at the
 295  * specified frame/uframe.  Note that (as summarized in section 11.19
 296  * of the usb 2.0 spec) TTs can buffer multiple transactions for each
 297  * uframe.
 298  *
 299  * The uframe parameter is when the fullspeed/lowspeed transfer
 300  * should be executed in "B-frame" terms, which is the same as the
 301  * highspeed ssplit's uframe (which is in "H-frame" terms).  For example
 302  * a ssplit in "H-frame" 0 causes a transfer in "B-frame" 0.
 303  * See the EHCI spec sec 4.5 and fig 4.7.
 304  *
 305  * This checks if the full/lowspeed bus, at the specified starting uframe,
 306  * has the specified bandwidth available, according to rules listed
 307  * in USB 2.0 spec section 11.18.1 fig 11-60.
 308  *
 309  * This does not check if the transfer would exceed the max ssplit
 310  * limit of 16, specified in USB 2.0 spec section 11.18.4 requirement #4,
 311  * since proper scheduling limits ssplits to less than 16 per uframe.
 312  */
 313 static int tt_available (
 314         struct ehci_hcd         *ehci,
 315         unsigned                period,
 316         struct usb_device       *dev,
 317         unsigned                frame,
 318         unsigned                uframe,
 319         u16                     usecs
 320 )
 321 {
 322         if ((period == 0) || (uframe >= 7))     /* error */
 323                 return 0;
 324
 325         for (; frame < ehci->periodic_size; frame += period) {
 326                 unsigned short tt_usecs[8];
 327
 328                 periodic_tt_usecs (ehci, dev, frame, tt_usecs);
 329
 330                 ehci_vdbg(ehci, "tt frame %d check %d usecs start uframe %d in"
 331                         " schedule %d/%d/%d/%d/%d/%d/%d/%d\n",
 332                         frame, usecs, uframe,
 333                         tt_usecs[0], tt_usecs[1], tt_usecs[2], tt_usecs[3],
 334                         tt_usecs[4], tt_usecs[5], tt_usecs[6], tt_usecs[7]);
 335
 336                 if (max_tt_usecs[uframe] <= tt_usecs[uframe]) {
 337                         ehci_vdbg(ehci, "frame %d uframe %d fully scheduled\n",
 338                                 frame, uframe);
 339                         return 0;
 340                 }
 341
 342                 /* special case for isoc transfers larger than 125us:
 343                  * the first and each subsequent fully used uframe
 344                  * must be empty, so as to not illegally delay
 345                  * already scheduled transactions
 346                  */
 347                 if (125 < usecs) {
 348                         int ufs = (usecs / 125);
 349                         int i;
 350                         for (i = uframe; i < (uframe + ufs) && i < 8; i++)
 351                                 if (0 < tt_usecs[i]) {
 352                                         ehci_vdbg(ehci,
 353                                                 "multi-uframe xfer can't fit "
 354                                                 "in frame %d uframe %d\n",
 355                                                 frame, i);
 356                                         return 0;
 357                                 }
 358                 }
 359
 360                 tt_usecs[uframe] += usecs;
 361
 362                 carryover_tt_bandwidth(tt_usecs);
 363
 364                 /* fail if the carryover pushed bw past the last uframe's limit */
 365                 if (max_tt_usecs[7] < tt_usecs[7]) {
 366                         ehci_vdbg(ehci,
 367                                 "tt unavailable usecs %d frame %d uframe %d\n",
 368                                 usecs, frame, uframe);
 369                         return 0;
 370                 }
 371         }
 372
 373         return 1;
 374 }
 375
 376 #else
 377
 378 /* return true iff the device's transaction translator is available
 379  * for a periodic transfer starting at the specified frame, using
 380  * all the uframes in the mask.
 381  */
 382 static int tt_no_collision (
 383         struct ehci_hcd         *ehci,
 384         unsigned                period,
 385         struct usb_device       *dev,
 386         unsigned                frame,
 387         u32                     uf_mask
 388 )
 389 {
 390         if (period == 0)        /* error */
 391                 return 0;
 392
 393         /* note bandwidth wastage:  split never follows csplit
 394          * (different dev or endpoint) until the next uframe.
 395          * calling convention doesn't make that distinction.
 396          */
 397         for (; frame < ehci->periodic_size; frame += period) {
 398                 union ehci_shadow       here;
 399                 __hc32                  type;
 400                 struct ehci_qh_hw       *hw;
 401
 402                 here = ehci->pshadow [frame];
 403                 type = Q_NEXT_TYPE(ehci, ehci->periodic [frame]);
 404                 while (here.ptr) {
 405                         switch (hc32_to_cpu(ehci, type)) {
 406                         case Q_TYPE_ITD:
 407                                 type = Q_NEXT_TYPE(ehci, here.itd->hw_next);
 408                                 here = here.itd->itd_next;
 409                                 continue;
 410                         case Q_TYPE_QH:
 411                                 hw = here.qh->hw;
 412                                 if (same_tt (dev, here.qh->dev)) {
 413                                         u32             mask;
 414
 415                                         mask = hc32_to_cpu(ehci,
 416                                                         hw->hw_info2);
 417                                         /* "knows" no gap is needed */
 418                                         mask |= mask >> 8;
 419                                         if (mask & uf_mask)
 420                                                 break;
 421                                 }
 422                                 type = Q_NEXT_TYPE(ehci, hw->hw_next);
 423                                 here = here.qh->qh_next;
 424                                 continue;
 425                         case Q_TYPE_SITD:
 426                                 if (same_tt (dev, here.sitd->urb->dev)) {
 427                                         u16             mask;
 428
 429                                         mask = hc32_to_cpu(ehci, here.sitd
 430                                                                 ->hw_uframe);
 431                                         /* FIXME assumes no gap for IN! */
 432                                         mask |= mask >> 8;
 433                                         if (mask & uf_mask)
 434                                                 break;
 435                                 }
 436                                 type = Q_NEXT_TYPE(ehci, here.sitd->hw_next);
 437                                 here = here.sitd->sitd_next;
 438                                 continue;
 439                         // case Q_TYPE_FSTN:
 440                         default:
 441                                 ehci_dbg (ehci,
 442                                         "periodic frame %d bogus type %d\n",
 443                                         frame, type);
 444                         }
 445
 446                         /* collision or error */
 447                         return 0;
 448                 }
 449         }
 450
 451         /* no collision */
 452         return 1;
 453 }
 454
 455 #endif /* CONFIG_USB_EHCI_TT_NEWSCHED */
 456
 457 /*-------------------------------------------------------------------------*/
 458
 459 static void enable_periodic(struct ehci_hcd *ehci)
 460 {
 461         if (ehci->periodic_count++)
 462                 return;
 463
 464         /* Stop waiting to turn off the periodic schedule */
 465         ehci->enabled_hrtimer_events &= ~BIT(EHCI_HRTIMER_DISABLE_PERIODIC);
 466
 467         /* Don't start the schedule until PSS is 0 */
 468         ehci_poll_PSS(ehci);
 469         turn_on_io_watchdog(ehci);
 470 }
 471
 472 static void disable_periodic(struct ehci_hcd *ehci)
 473 {
 474         if (--ehci->periodic_count)
 475                 return;
 476
 477         /* Don't turn off the schedule until PSS is 1 */
 478         ehci_poll_PSS(ehci);
 479 }
 480
 481 /*-------------------------------------------------------------------------*/
 482
 483 /* periodic schedule slots have iso tds (normal or split) first, then a
 484  * sparse tree for active interrupt transfers.
 485  *
 486  * this just links in a qh; caller guarantees uframe masks are set right.
 487  * no FSTN support (yet; ehci 0.96+)
 488  */
 489 static void qh_link_periodic(struct ehci_hcd *ehci, struct ehci_qh *qh)
 490 {
 491         unsigned        i;
 492         unsigned        period = qh->period;
 493
 494         dev_dbg (&qh->dev->dev,
 495                 "link qh%d-%04x/%p start %d [%d/%d us]\n",
 496                 period, hc32_to_cpup(ehci, &qh->hw->hw_info2)
 497                         & (QH_CMASK | QH_SMASK),
 498                 qh, qh->start, qh->usecs, qh->c_usecs);
 499
 500         /* high bandwidth, or otherwise every microframe */
 501         if (period == 0)
 502                 period = 1;
 503
 504         for (i = qh->start; i < ehci->periodic_size; i += period) {
 505                 union ehci_shadow       *prev = &ehci->pshadow[i];
 506                 __hc32                  *hw_p = &ehci->periodic[i];
 507                 union ehci_shadow       here = *prev;
 508                 __hc32                  type = 0;
 509
 510                 /* skip the iso nodes at list head */
 511                 while (here.ptr) {
 512                         type = Q_NEXT_TYPE(ehci, *hw_p);
 513                         if (type == cpu_to_hc32(ehci, Q_TYPE_QH))
 514                                 break;
 515                         prev = periodic_next_shadow(ehci, prev, type);
 516                         hw_p = shadow_next_periodic(ehci, &here, type);
 517                         here = *prev;
 518                 }
 519
 520                 /* sorting each branch by period (slow-->fast)
 521                  * enables sharing interior tree nodes
 522                  */
 523                 while (here.ptr && qh != here.qh) {
 524                         if (qh->period > here.qh->period)
 525                                 break;
 526                         prev = &here.qh->qh_next;
 527                         hw_p = &here.qh->hw->hw_next;
 528                         here = *prev;
 529                 }
 530                 /* link in this qh, unless some earlier pass did that */
 531                 if (qh != here.qh) {
 532                         qh->qh_next = here;
 533                         if (here.qh)
 534                                 qh->hw->hw_next = *hw_p;
 535                         wmb ();
 536                         prev->qh = qh;
 537                         *hw_p = QH_NEXT (ehci, qh->qh_dma);
 538                 }
 539         }
 540         qh->qh_state = QH_STATE_LINKED;
 541         qh->xacterrs = 0;
 542         qh->exception = 0;
 543
 544         /* update per-qh bandwidth for usbfs */
 545         ehci_to_hcd(ehci)->self.bandwidth_allocated += qh->period
 546                 ? ((qh->usecs + qh->c_usecs) / qh->period)
 547                 : (qh->usecs * 8);
 548
 549         list_add(&qh->intr_node, &ehci->intr_qh_list);
 550
 551         /* maybe enable periodic schedule processing */
 552         ++ehci->intr_count;
 553         enable_periodic(ehci);
 554 }
 555
 556 static void qh_unlink_periodic(struct ehci_hcd *ehci, struct ehci_qh *qh)
 557 {
 558         unsigned        i;
 559         unsigned        period;
 560
 561         /*
 562          * If qh is for a low/full-speed device, simply unlinking it
 563          * could interfere with an ongoing split transaction.  To unlink
 564          * it safely would require setting the QH_INACTIVATE bit and
 565          * waiting at least one frame, as described in EHCI 4.12.2.5.
 566          *
 567          * We won't bother with any of this.  Instead, we assume that the
 568          * only reason for unlinking an interrupt QH while the current URB
 569          * is still active is to dequeue all the URBs (flush the whole
 570          * endpoint queue).
 571          *
 572          * If rebalancing the periodic schedule is ever implemented, this
 573          * approach will no longer be valid.
 574          */
 575
 576         /* high bandwidth, or otherwise part of every microframe */
 577         if ((period = qh->period) == 0)
 578                 period = 1;
 579
 580         for (i = qh->start; i < ehci->periodic_size; i += period)
 581                 periodic_unlink (ehci, i, qh);
 582
 583         /* update per-qh bandwidth for usbfs */
 584         ehci_to_hcd(ehci)->self.bandwidth_allocated -= qh->period
 585                 ? ((qh->usecs + qh->c_usecs) / qh->period)
 586                 : (qh->usecs * 8);
 587
 588         dev_dbg (&qh->dev->dev,
 589                 "unlink qh%d-%04x/%p start %d [%d/%d us]\n",
 590                 qh->period,
 591                 hc32_to_cpup(ehci, &qh->hw->hw_info2) & (QH_CMASK | QH_SMASK),
 592                 qh, qh->start, qh->usecs, qh->c_usecs);
 593
 594         /* qh->qh_next still "live" to HC */
 595         qh->qh_state = QH_STATE_UNLINK;
 596         qh->qh_next.ptr = NULL;
 597
 598         if (ehci->qh_scan_next == qh)
 599                 ehci->qh_scan_next = list_entry(qh->intr_node.next,
 600                                 struct ehci_qh, intr_node);
 601         list_del(&qh->intr_node);
 602 }
 603
 604 static void start_unlink_intr(struct ehci_hcd *ehci, struct ehci_qh *qh)
 605 {
 606         /* If the QH isn't linked then there's nothing we can do. */
 607         if (qh->qh_state != QH_STATE_LINKED)
 608                 return;
 609
 610         qh_unlink_periodic (ehci, qh);
 611
 612         /* Make sure the unlinks are visible before starting the timer */
 613         wmb();
 614
 615         /*
 616          * The EHCI spec doesn't say how long it takes the controller to
 617          * stop accessing an unlinked interrupt QH.  The timer delay is
 618          * 9 uframes; presumably that will be long enough.
 619          */
 620         qh->unlink_cycle = ehci->intr_unlink_cycle;
 621
 622         /* New entries go at the end of the intr_unlink list */
 623         list_add_tail(&qh->unlink_node, &ehci->intr_unlink);
 624
 625         if (ehci->intr_unlinking)
 626                 ;       /* Avoid recursive calls */
 627         else if (ehci->rh_state < EHCI_RH_RUNNING)
 628                 ehci_handle_intr_unlinks(ehci);
 629         else if (ehci->intr_unlink.next == &qh->unlink_node) {
 630                 ehci_enable_event(ehci, EHCI_HRTIMER_UNLINK_INTR, true);
 631                 ++ehci->intr_unlink_cycle;
 632         }
 633 }
 634
 635 static void end_unlink_intr(struct ehci_hcd *ehci, struct ehci_qh *qh)
 636 {
 637         struct ehci_qh_hw       *hw = qh->hw;
 638         int                     rc;
 639
 640         qh->qh_state = QH_STATE_IDLE;
 641         hw->hw_next = EHCI_LIST_END(ehci);
 642
 643         if (!list_empty(&qh->qtd_list))
 644                 qh_completions(ehci, qh);
 645
 646         /* reschedule QH iff another request is queued */
 647         if (!list_empty(&qh->qtd_list) && ehci->rh_state == EHCI_RH_RUNNING) {
 648                 rc = qh_schedule(ehci, qh);
 649                 if (rc == 0) {
 650                         qh_refresh(ehci, qh);
 651                         qh_link_periodic(ehci, qh);
 652                 }
 653
 654                 /* An error here likely indicates handshake failure
 655                  * or no space left in the schedule.  Neither fault
 656                  * should happen often ...
 657                  *
 658                  * FIXME kill the now-dysfunctional queued urbs
 659                  */
 660                 else {
 661                         ehci_err(ehci, "can't reschedule qh %p, err %d\n",
 662                                         qh, rc);
 663                 }
 664         }
 665
 666         /* maybe turn off periodic schedule */
 667         --ehci->intr_count;
 668         disable_periodic(ehci);
 669 }
 670
 671 /*-------------------------------------------------------------------------*/
 672
 673 static int check_period (
 674         struct ehci_hcd *ehci,
 675         unsigned        frame,
 676         unsigned        uframe,
 677         unsigned        period,
 678         unsigned        usecs
 679 ) {
 680         int             claimed;
 681
 682         /* complete split running into next frame?
 683          * given FSTN support, we could sometimes check...
 684          */
 685         if (uframe >= 8)
 686                 return 0;
 687
 688         /* convert "usecs we need" to "max already claimed" */
 689         usecs = ehci->uframe_periodic_max - usecs;
 690
 691         /* we "know" 2 and 4 uframe intervals were rejected; so
 692          * for period 0, check _every_ microframe in the schedule.
 693          */
 694         if (unlikely (period == 0)) {
 695                 do {
 696                         for (uframe = 0; uframe < 7; uframe++) {
 697                                 claimed = periodic_usecs (ehci, frame, uframe);
 698                                 if (claimed > usecs)
 699                                         return 0;
 700                         }
 701                 } while ((frame += 1) < ehci->periodic_size);
 702
 703         /* just check the specified uframe, at that period */
 704         } else {
 705                 do {
 706                         claimed = periodic_usecs (ehci, frame, uframe);
 707                         if (claimed > usecs)
 708                                 return 0;
 709                 } while ((frame += period) < ehci->periodic_size);
 710         }
 711
 712         // success!
 713         return 1;
 714 }
 715
 716 static int check_intr_schedule (
 717         struct ehci_hcd         *ehci,
 718         unsigned                frame,
 719         unsigned                uframe,
 720         const struct ehci_qh    *qh,
 721         __hc32                  *c_maskp
 722 )
 723 {
 724         int             retval = -ENOSPC;
 725         u8              mask = 0;
 726
 727         if (qh->c_usecs && uframe >= 6)         /* FSTN territory? */
 728                 goto done;
 729
 730         if (!check_period (ehci, frame, uframe, qh->period, qh->usecs))
 731                 goto done;
 732         if (!qh->c_usecs) {
 733                 retval = 0;
 734                 *c_maskp = 0;
 735                 goto done;
 736         }
 737
 738 #ifdef CONFIG_USB_EHCI_TT_NEWSCHED
 739         if (tt_available (ehci, qh->period, qh->dev, frame, uframe,
 740                                 qh->tt_usecs)) {
 741                 unsigned i;
 742
 743                 /* TODO : this may need FSTN for SSPLIT in uframe 5. */
 744                 for (i=uframe+1; i<8 && i<uframe+4; i++)
 745                         if (!check_period (ehci, frame, i,
 746                                                 qh->period, qh->c_usecs))
 747                                 goto done;
 748                         else
 749                                 mask |= 1 << i;
 750
 751                 retval = 0;
 752
 753                 *c_maskp = cpu_to_hc32(ehci, mask << 8);
 754         }
 755 #else
 756         /* Make sure this tt's buffer is also available for CSPLITs.
 757          * We pessimize a bit; probably the typical full speed case
 758          * doesn't need the second CSPLIT.
 759          *
 760          * NOTE:  both SPLIT and CSPLIT could be checked in just
 761          * one smart pass...
 762          */
 763         mask = 0x03 << (uframe + qh->gap_uf);
 764         *c_maskp = cpu_to_hc32(ehci, mask << 8);
 765
 766         mask |= 1 << uframe;
 767         if (tt_no_collision (ehci, qh->period, qh->dev, frame, mask)) {
 768                 if (!check_period (ehci, frame, uframe + qh->gap_uf + 1,
 769                                         qh->period, qh->c_usecs))
 770                         goto done;
 771                 if (!check_period (ehci, frame, uframe + qh->gap_uf,
 772                                         qh->period, qh->c_usecs))
 773                         goto done;
 774                 retval = 0;
 775         }
 776 #endif
 777 done:
 778         return retval;
 779 }
 780
 781 /* "first fit" scheduling policy used the first time through,
 782  * or when the previous schedule slot can't be re-used.
 783  */
 784 static int qh_schedule(struct ehci_hcd *ehci, struct ehci_qh *qh)
 785 {
 786         int             status;
 787         unsigned        uframe;
 788         __hc32          c_mask;
 789         unsigned        frame;          /* 0..(qh->period - 1), or NO_FRAME */
 790         struct ehci_qh_hw       *hw = qh->hw;
 791
 792         hw->hw_next = EHCI_LIST_END(ehci);
 793         frame = qh->start;
 794
 795         /* reuse the previous schedule slots, if we can */
 796         if (frame < qh->period) {
 797                 uframe = ffs(hc32_to_cpup(ehci, &hw->hw_info2) & QH_SMASK);
 798                 status = check_intr_schedule (ehci, frame, --uframe,
 799                                 qh, &c_mask);
 800         } else {
 801                 uframe = 0;
 802                 c_mask = 0;
 803                 status = -ENOSPC;
 804         }
 805
 806         /* else scan the schedule to find a group of slots such that all
 807          * uframes have enough periodic bandwidth available.
 808          */
 809         if (status) {
 810                 /* "normal" case, uframing flexible except with splits */
 811                 if (qh->period) {
 812                         int             i;
 813
 814                         for (i = qh->period; status && i > 0; --i) {
 815                                 frame = ++ehci->random_frame % qh->period;
 816                                 for (uframe = 0; uframe < 8; uframe++) {
 817                                         status = check_intr_schedule (ehci,
 818                                                         frame, uframe, qh,
 819                                                         &c_mask);
 820                                         if (status == 0)
 821                                                 break;
 822                                 }
 823                         }
 824
 825                 /* qh->period == 0 means every uframe */
 826                 } else {
 827                         frame = 0;
 828                         status = check_intr_schedule (ehci, 0, 0, qh, &c_mask);
 829                 }
 830                 if (status)
 831                         goto done;
 832                 qh->start = frame;
 833
 834                 /* reset S-frame and (maybe) C-frame masks */
 835                 hw->hw_info2 &= cpu_to_hc32(ehci, ~(QH_CMASK | QH_SMASK));
 836                 hw->hw_info2 |= qh->period
 837                         ? cpu_to_hc32(ehci, 1 << uframe)
 838                         : cpu_to_hc32(ehci, QH_SMASK);
 839                 hw->hw_info2 |= c_mask;
 840         } else
 841                 ehci_dbg (ehci, "reused qh %p schedule\n", qh);
 842
 843 done:
 844         return status;
 845 }
 846
 847 static int intr_submit (
 848         struct ehci_hcd         *ehci,
 849         struct urb              *urb,
 850         struct list_head        *qtd_list,
 851         gfp_t                   mem_flags
 852 ) {
 853         unsigned                epnum;
 854         unsigned long           flags;
 855         struct ehci_qh          *qh;
 856         int                     status;
 857         struct list_head        empty;
 858
 859         /* get endpoint and transfer/schedule data */
 860         epnum = urb->ep->desc.bEndpointAddress;
 861
 862         spin_lock_irqsave (&ehci->lock, flags);
 863
 864         if (unlikely(!HCD_HW_ACCESSIBLE(ehci_to_hcd(ehci)))) {
 865                 status = -ESHUTDOWN;
 866                 goto done_not_linked;
 867         }
 868         status = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
 869         if (unlikely(status))
 870                 goto done_not_linked;
 871
 872         /* get qh and force any scheduling errors */
 873         INIT_LIST_HEAD (&empty);
 874         qh = qh_append_tds(ehci, urb, &empty, epnum, &urb->ep->hcpriv);
 875         if (qh == NULL) {
 876                 status = -ENOMEM;
 877                 goto done;
 878         }
 879         if (qh->qh_state == QH_STATE_IDLE) {
 880                 if ((status = qh_schedule (ehci, qh)) != 0)
 881                         goto done;
 882         }
 883
 884         /* then queue the urb's tds to the qh */
 885         qh = qh_append_tds(ehci, urb, qtd_list, epnum, &urb->ep->hcpriv);
 886         BUG_ON (qh == NULL);
 887
 888         /* stuff into the periodic schedule */
 889         if (qh->qh_state == QH_STATE_IDLE) {
 890                 qh_refresh(ehci, qh);
 891                 qh_link_periodic(ehci, qh);
 892         }
 893
 894         /* ... update usbfs periodic stats */
 895         ehci_to_hcd(ehci)->self.bandwidth_int_reqs++;
 896
 897 done:
 898         if (unlikely(status))
 899                 usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
 900 done_not_linked:
 901         spin_unlock_irqrestore (&ehci->lock, flags);
 902         if (status)
 903                 qtd_list_free (ehci, urb, qtd_list);
 904
 905         return status;
 906 }
 907
 908 static void scan_intr(struct ehci_hcd *ehci)
 909 {
 910         struct ehci_qh          *qh;
 911
 912         list_for_each_entry_safe(qh, ehci->qh_scan_next, &ehci->intr_qh_list,
 913                         intr_node) {
 914
 915                 /* clean any finished work for this qh */
 916                 if (!list_empty(&qh->qtd_list)) {
 917                         int temp;
 918
 919                         /*
 920                          * Unlinks could happen here; completion reporting
 921                          * drops the lock.  That's why ehci->qh_scan_next
 922                          * always holds the next qh to scan; if the next qh
 923                          * gets unlinked then ehci->qh_scan_next is adjusted
 924                          * in qh_unlink_periodic().
 925                          */
 926                         temp = qh_completions(ehci, qh);
 927                         if (unlikely(temp || (list_empty(&qh->qtd_list) &&
 928                                         qh->qh_state == QH_STATE_LINKED)))
 929                                 start_unlink_intr(ehci, qh);
 930                 }
 931         }
 932 }
 933
 934 /*-------------------------------------------------------------------------*/
 935
 936 /* ehci_iso_stream ops work with both ITD and SITD */
 937
 938 static struct ehci_iso_stream *
 939 iso_stream_alloc (gfp_t mem_flags)
 940 {
 941         struct ehci_iso_stream *stream;
 942
 943         stream = kzalloc(sizeof *stream, mem_flags);
 944         if (likely (stream != NULL)) {
 945                 INIT_LIST_HEAD(&stream->td_list);
 946                 INIT_LIST_HEAD(&stream->free_list);
 947                 stream->next_uframe = -1;
 948         }
 949         return stream;
 950 }
 951
 952 static void
 953 iso_stream_init (
 954         struct ehci_hcd         *ehci,
 955         struct ehci_iso_stream  *stream,
 956         struct usb_device       *dev,
 957         int                     pipe,
 958         unsigned                interval
 959 )
 960 {
 961         static const u8 smask_out [] = { 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f };
 962
 963         u32                     buf1;
 964         unsigned                epnum, maxp;
 965         int                     is_input;
 966         long                    bandwidth;
 967
 968         /*
 969          * this might be a "high bandwidth" highspeed endpoint,
 970          * as encoded in the ep descriptor's wMaxPacket field
 971          */
 972         epnum = usb_pipeendpoint (pipe);
 973         is_input = usb_pipein (pipe) ? USB_DIR_IN : 0;
 974         maxp = usb_maxpacket(dev, pipe, !is_input);
 975         if (is_input) {
 976                 buf1 = (1 << 11);
 977         } else {
 978                 buf1 = 0;
 979         }
 980
 981         /* knows about ITD vs SITD */
 982         if (dev->speed == USB_SPEED_HIGH) {
 983                 unsigned multi = hb_mult(maxp);
 984
 985                 stream->highspeed = 1;
 986
 987                 maxp = max_packet(maxp);
 988                 buf1 |= maxp;
 989                 maxp *= multi;
 990
 991                 stream->buf0 = cpu_to_hc32(ehci, (epnum << 8) | dev->devnum);
 992                 stream->buf1 = cpu_to_hc32(ehci, buf1);
 993                 stream->buf2 = cpu_to_hc32(ehci, multi);
 994
 995                 /* usbfs wants to report the average usecs per frame tied up
 996                  * when transfers on this endpoint are scheduled ...
 997                  */
 998                 stream->usecs = HS_USECS_ISO (maxp);
 999                 bandwidth = stream->usecs * 8;
1000                 bandwidth /= interval;
1001
1002         } else {
1003                 u32             addr;
1004                 int             think_time;
1005                 int             hs_transfers;
1006
1007                 addr = dev->ttport << 24;
1008                 if (!ehci_is_TDI(ehci)
1009                                 || (dev->tt->hub !=
1010                                         ehci_to_hcd(ehci)->self.root_hub))
1011                         addr |= dev->tt->hub->devnum << 16;
1012                 addr |= epnum << 8;
1013                 addr |= dev->devnum;
1014                 stream->usecs = HS_USECS_ISO (maxp);
1015                 think_time = dev->tt ? dev->tt->think_time : 0;
1016                 stream->tt_usecs = NS_TO_US (think_time + usb_calc_bus_time (
1017                                 dev->speed, is_input, 1, maxp));
1018                 hs_transfers = max (1u, (maxp + 187) / 188);
1019                 if (is_input) {
1020                         u32     tmp;
1021
1022                         addr |= 1 << 31;
1023                         stream->c_usecs = stream->usecs;
1024                         stream->usecs = HS_USECS_ISO (1);
1025                         stream->raw_mask = 1;
1026
1027                         /* c-mask as specified in USB 2.0 11.18.4 3.c */
1028                         tmp = (1 << (hs_transfers + 2)) - 1;
1029                         stream->raw_mask |= tmp << (8 + 2);
1030                 } else
1031                         stream->raw_mask = smask_out [hs_transfers - 1];
1032                 bandwidth = stream->usecs + stream->c_usecs;
1033                 bandwidth /= interval << 3;
1034
1035                 /* stream->splits gets created from raw_mask later */
1036                 stream->address = cpu_to_hc32(ehci, addr);
1037         }
1038         stream->bandwidth = bandwidth;
1039
1040         stream->udev = dev;
1041
1042         stream->bEndpointAddress = is_input | epnum;
1043         stream->interval = interval;
1044         stream->maxp = maxp;
1045 }
1046
1047 static struct ehci_iso_stream *
1048 iso_stream_find (struct ehci_hcd *ehci, struct urb *urb)
1049 {
1050         unsigned                epnum;
1051         struct ehci_iso_stream  *stream;
1052         struct usb_host_endpoint *ep;
1053         unsigned long           flags;
1054
1055         epnum = usb_pipeendpoint (urb->pipe);
1056         if (usb_pipein(urb->pipe))
1057                 ep = urb->dev->ep_in[epnum];
1058         else
1059                 ep = urb->dev->ep_out[epnum];
1060
1061         spin_lock_irqsave (&ehci->lock, flags);
1062         stream = ep->hcpriv;
1063
1064         if (unlikely (stream == NULL)) {
1065                 stream = iso_stream_alloc(GFP_ATOMIC);
1066                 if (likely (stream != NULL)) {
1067                         ep->hcpriv = stream;
1068                         stream->ep = ep;
1069                         iso_stream_init(ehci, stream, urb->dev, urb->pipe,
1070                                         urb->interval);
1071                 }
1072
1073         /* if dev->ep [epnum] is a QH, hw is set */
1074         } else if (unlikely (stream->hw != NULL)) {
1075                 ehci_dbg (ehci, "dev %s ep%d%s, not iso??\n",
1076                         urb->dev->devpath, epnum,
1077                         usb_pipein(urb->pipe) ? "in" : "out");
1078                 stream = NULL;
1079         }
1080
1081         spin_unlock_irqrestore (&ehci->lock, flags);
1082         return stream;
1083 }
1084
1085 /*-------------------------------------------------------------------------*/
1086
1087 /* ehci_iso_sched ops can be ITD-only or SITD-only */
1088
1089 static struct ehci_iso_sched *
1090 iso_sched_alloc (unsigned packets, gfp_t mem_flags)
1091 {
1092         struct ehci_iso_sched   *iso_sched;
1093         int                     size = sizeof *iso_sched;
1094
1095         size += packets * sizeof (struct ehci_iso_packet);
1096         iso_sched = kzalloc(size, mem_flags);
1097         if (likely (iso_sched != NULL)) {
1098                 INIT_LIST_HEAD (&iso_sched->td_list);
1099         }
1100         return iso_sched;
1101 }
1102
1103 static inline void
1104 itd_sched_init(
1105         struct ehci_hcd         *ehci,
1106         struct ehci_iso_sched   *iso_sched,
1107         struct ehci_iso_stream  *stream,
1108         struct urb              *urb
1109 )
1110 {
1111         unsigned        i;
1112         dma_addr_t      dma = urb->transfer_dma;
1113
1114         /* how many uframes are needed for these transfers */
1115         iso_sched->span = urb->number_of_packets * stream->interval;
1116
1117         /* figure out per-uframe itd fields that we'll need later
1118          * when we fit new itds into the schedule.
1119          */
1120         for (i = 0; i < urb->number_of_packets; i++) {
1121                 struct ehci_iso_packet  *uframe = &iso_sched->packet [i];
1122                 unsigned                length;
1123                 dma_addr_t              buf;
1124                 u32                     trans;
1125
1126                 length = urb->iso_frame_desc [i].length;
1127                 buf = dma + urb->iso_frame_desc [i].offset;
1128
1129                 trans = EHCI_ISOC_ACTIVE;
1130                 trans |= buf & 0x0fff;
1131                 if (unlikely (((i + 1) == urb->number_of_packets))
1132                                 && !(urb->transfer_flags & URB_NO_INTERRUPT))
1133                         trans |= EHCI_ITD_IOC;
1134                 trans |= length << 16;
1135                 uframe->transaction = cpu_to_hc32(ehci, trans);
1136
1137                 /* might need to cross a buffer page within a uframe */
1138                 uframe->bufp = (buf & ~(u64)0x0fff);
1139                 buf += length;
1140                 if (unlikely ((uframe->bufp != (buf & ~(u64)0x0fff))))
1141                         uframe->cross = 1;
1142         }
1143 }
1144
1145 static void
1146 iso_sched_free (
1147         struct ehci_iso_stream  *stream,
1148         struct ehci_iso_sched   *iso_sched
1149 )
1150 {
1151         if (!iso_sched)
1152                 return;
1153         // caller must hold ehci->lock!
1154         list_splice (&iso_sched->td_list, &stream->free_list);
1155         kfree (iso_sched);
1156 }
1157
1158 static int
1159 itd_urb_transaction (
1160         struct ehci_iso_stream  *stream,
1161         struct ehci_hcd         *ehci,
1162         struct urb              *urb,
1163         gfp_t                   mem_flags
1164 )
1165 {
1166         struct ehci_itd         *itd;
1167         dma_addr_t              itd_dma;
1168         int                     i;
1169         unsigned                num_itds;
1170         struct ehci_iso_sched   *sched;
1171         unsigned long           flags;
1172
1173         sched = iso_sched_alloc (urb->number_of_packets, mem_flags);
1174         if (unlikely (sched == NULL))
1175                 return -ENOMEM;
1176
1177         itd_sched_init(ehci, sched, stream, urb);
1178
1179         if (urb->interval < 8)
1180                 num_itds = 1 + (sched->span + 7) / 8;
1181         else
1182                 num_itds = urb->number_of_packets;
1183
1184         /* allocate/init ITDs */
1185         spin_lock_irqsave (&ehci->lock, flags);
1186         for (i = 0; i < num_itds; i++) {
1187
1188                 /*
1189                  * Use iTDs from the free list, but not iTDs that may
1190                  * still be in use by the hardware.
1191                  */
1192                 if (likely(!list_empty(&stream->free_list))) {
1193                         itd = list_first_entry(&stream->free_list,
1194                                         struct ehci_itd, itd_list);
1195                         if (itd->frame == ehci->now_frame)
1196                                 goto alloc_itd;
1197                         list_del (&itd->itd_list);
1198                         itd_dma = itd->itd_dma;
1199                 } else {
1200  alloc_itd:
1201                         spin_unlock_irqrestore (&ehci->lock, flags);
1202                         itd = dma_pool_alloc (ehci->itd_pool, mem_flags,
1203                                         &itd_dma);
1204                         spin_lock_irqsave (&ehci->lock, flags);
1205                         if (!itd) {
1206                                 iso_sched_free(stream, sched);
1207                                 spin_unlock_irqrestore(&ehci->lock, flags);
1208                                 return -ENOMEM;
1209                         }
1210                 }
1211
1212                 memset (itd, 0, sizeof *itd);
1213                 itd->itd_dma = itd_dma;
1214                 itd->frame = 9999;              /* an invalid value */
1215                 list_add (&itd->itd_list, &sched->td_list);
1216         }
1217         spin_unlock_irqrestore (&ehci->lock, flags);
1218
1219         /* temporarily store schedule info in hcpriv */
1220         urb->hcpriv = sched;
1221         urb->error_count = 0;
1222         return 0;
1223 }
1224
1225 /*-------------------------------------------------------------------------*/
1226
1227 static inline int
1228 itd_slot_ok (
1229         struct ehci_hcd         *ehci,
1230         u32                     mod,
1231         u32                     uframe,
1232         u8                      usecs,
1233         u32                     period
1234 )
1235 {
1236         uframe %= period;
1237         do {
1238                 /* can't commit more than uframe_periodic_max usec */
1239                 if (periodic_usecs (ehci, uframe >> 3, uframe & 0x7)
1240                                 > (ehci->uframe_periodic_max - usecs))
1241                         return 0;
1242
1243                 /* we know urb->interval is 2^N uframes */
1244                 uframe += period;
1245         } while (uframe < mod);
1246         return 1;
1247 }
1248
1249 static inline int
1250 sitd_slot_ok (
1251         struct ehci_hcd         *ehci,
1252         u32                     mod,
1253         struct ehci_iso_stream  *stream,
1254         u32                     uframe,
1255         struct ehci_iso_sched   *sched,
1256         u32                     period_uframes
1257 )
1258 {
1259         u32                     mask, tmp;
1260         u32                     frame, uf;
1261
1262         mask = stream->raw_mask << (uframe & 7);
1263
1264         /* for IN, don't wrap CSPLIT into the next frame */
1265         if (mask & ~0xffff)
1266                 return 0;
1267
1268         /* check bandwidth */
1269         uframe %= period_uframes;
1270         frame = uframe >> 3;
1271
1272 #ifdef CONFIG_USB_EHCI_TT_NEWSCHED
1273         /* The tt's fullspeed bus bandwidth must be available.
1274          * tt_available scheduling guarantees 10+% for control/bulk.
1275          */
1276         uf = uframe & 7;
1277         if (!tt_available(ehci, period_uframes >> 3,
1278                         stream->udev, frame, uf, stream->tt_usecs))
1279                 return 0;
1280 #else
1281         /* tt must be idle for start(s), any gap, and csplit.
1282          * assume scheduling slop leaves 10+% for control/bulk.
1283          */
1284         if (!tt_no_collision(ehci, period_uframes >> 3,
1285                         stream->udev, frame, mask))
1286                 return 0;
1287 #endif
1288
1289         /* this multi-pass logic is simple, but performance may
1290          * suffer when the schedule data isn't cached.
1291          */
1292         do {
1293                 u32             max_used;
1294
1295                 frame = uframe >> 3;
1296                 uf = uframe & 7;
1297
1298                 /* check starts (OUT uses more than one) */
1299                 max_used = ehci->uframe_periodic_max - stream->usecs;
1300                 for (tmp = stream->raw_mask & 0xff; tmp; tmp >>= 1, uf++) {
1301                         if (periodic_usecs (ehci, frame, uf) > max_used)
1302                                 return 0;
1303                 }
1304
1305                 /* for IN, check CSPLIT */
1306                 if (stream->c_usecs) {
1307                         uf = uframe & 7;
1308                         max_used = ehci->uframe_periodic_max - stream->c_usecs;
1309                         do {
1310                                 tmp = 1 << uf;
1311                                 tmp <<= 8;
1312                                 if ((stream->raw_mask & tmp) == 0)
1313                                         continue;
1314                                 if (periodic_usecs (ehci, frame, uf)
1315                                                 > max_used)
1316                                         return 0;
1317                         } while (++uf < 8);
1318                 }
1319
1320                 /* we know urb->interval is 2^N uframes */
1321                 uframe += period_uframes;
1322         } while (uframe < mod);
1323
1324         stream->splits = cpu_to_hc32(ehci, stream->raw_mask << (uframe & 7));
1325         return 1;
1326 }
1327
1328 /*
1329  * This scheduler plans almost as far into the future as it has actual
1330  * periodic schedule slots.  (Affected by TUNE_FLS, which defaults to
1331  * "as small as possible" to be cache-friendlier.)  That limits the size
1332  * transfers you can stream reliably; avoid more than 64 msec per urb.
1333  * Also avoid queue depths of less than ehci's worst irq latency (affected
1334  * by the per-urb URB_NO_INTERRUPT hint, the log2_irq_thresh module parameter,
1335  * and other factors); or more than about 230 msec total (for portability,
1336  * given EHCI_TUNE_FLS and the slop).  Or, write a smarter scheduler!
1337  */
1338
1339 #define SCHEDULING_DELAY        40      /* microframes */
1340
1341 static int
1342 iso_stream_schedule (
1343         struct ehci_hcd         *ehci,
1344         struct urb              *urb,
1345         struct ehci_iso_stream  *stream
1346 )
1347 {
1348         u32                     now, base, next, start, period, span;
1349         int                     status;
1350         unsigned                mod = ehci->periodic_size << 3;
1351         struct ehci_iso_sched   *sched = urb->hcpriv;
1352
1353         period = urb->interval;
1354         span = sched->span;
1355         if (!stream->highspeed) {
1356                 period <<= 3;
1357                 span <<= 3;
1358         }
1359
1360         now = ehci_read_frame_index(ehci) & (mod - 1);
1361
1362         /* Typical case: reuse current schedule, stream is still active.
1363          * Hopefully there are no gaps from the host falling behind
1364          * (irq delays etc).  If there are, the behavior depends on
1365          * whether URB_ISO_ASAP is set.
1366          */
1367         if (likely (!list_empty (&stream->td_list))) {
1368
1369                 /* Take the isochronous scheduling threshold into account */
1370                 if (ehci->i_thresh)
1371                         next = now + ehci->i_thresh;    /* uframe cache */
1372                 else
1373                         next = (now + 2 + 7) & ~0x07;   /* full frame cache */
1374
1375                 /*
1376                  * Use ehci->last_iso_frame as the base.  There can't be any
1377                  * TDs scheduled for earlier than that.
1378                  */
1379                 base = ehci->last_iso_frame << 3;
1380                 next = (next - base) & (mod - 1);
1381                 start = (stream->next_uframe - base) & (mod - 1);
1382
1383                 /* Is the schedule already full? */
1384                 if (unlikely(start < period)) {
1385                         ehci_dbg(ehci, "iso sched full %p (%u-%u < %u mod %u)\n",
1386                                         urb, stream->next_uframe, base,
1387                                         period, mod);
1388                         status = -ENOSPC;
1389                         goto fail;
1390                 }
1391
1392                 /* Behind the scheduling threshold? */
1393                 if (unlikely(start < next)) {
1394                         unsigned now2 = (now - base) & (mod - 1);
1395
1396                         /* USB_ISO_ASAP: Round up to the first available slot */
1397                         if (urb->transfer_flags & URB_ISO_ASAP)
1398                                 start += (next - start + period - 1) & -period;
1399
1400                         /*
1401                          * Not ASAP: Use the next slot in the stream,
1402                          * no matter what.
1403                          */
1404                         else if (start + span - period < now2) {
1405                                 ehci_dbg(ehci, "iso underrun %p (%u+%u < %u)\n",
1406                                                 urb, start + base,
1407                                                 span - period, now2 + base);
1408                         }
1409                 }
1410
1411                 start += base;
1412         }
1413
1414         /* need to schedule; when's the next (u)frame we could start?
1415          * this is bigger than ehci->i_thresh allows; scheduling itself
1416          * isn't free, the delay should handle reasonably slow cpus.  it
1417          * can also help high bandwidth if the dma and irq loads don't
1418          * jump until after the queue is primed.
1419          */
1420         else {
1421                 int done = 0;
1422
1423                 base = now & ~0x07;
1424                 start = base + SCHEDULING_DELAY;
1425
1426                 /* find a uframe slot with enough bandwidth.
1427                  * Early uframes are more precious because full-speed
1428                  * iso IN transfers can't use late uframes,
1429                  * and therefore they should be allocated last.
1430                  */
1431                 next = start;
1432                 start += period;
1433                 do {
1434                         start--;
1435                         /* check schedule: enough space? */
1436                         if (stream->highspeed) {
1437                                 if (itd_slot_ok(ehci, mod, start,
1438                                                 stream->usecs, period))
1439                                         done = 1;
1440                         } else {
1441                                 if ((start % 8) >= 6)
1442                                         continue;
1443                                 if (sitd_slot_ok(ehci, mod, stream,
1444                                                 start, sched, period))
1445                                         done = 1;
1446                         }
1447                 } while (start > next && !done);
1448
1449                 /* no room in the schedule */
1450                 if (!done) {
1451                         ehci_dbg(ehci, "iso sched full %p", urb);
1452                         status = -ENOSPC;
1453                         goto fail;
1454                 }
1455         }
1456
1457         /* Tried to schedule too far into the future? */
1458         if (unlikely(start - base + span - period >= mod)) {
1459                 ehci_dbg(ehci, "request %p would overflow (%u+%u >= %u)\n",
1460                                 urb, start - base, span - period, mod);
1461                 status = -EFBIG;
1462                 goto fail;
1463         }
1464
1465         stream->next_uframe = start & (mod - 1);
1466
1467         /* report high speed start in uframes; full speed, in frames */
1468         urb->start_frame = stream->next_uframe;
1469         if (!stream->highspeed)
1470                 urb->start_frame >>= 3;
1471
1472         /* Make sure scan_isoc() sees these */
1473         if (ehci->isoc_count == 0)
1474                 ehci->last_iso_frame = now >> 3;
1475         return 0;
1476
1477  fail:
1478         iso_sched_free(stream, sched);
1479         urb->hcpriv = NULL;
1480         return status;
1481 }
1482
1483 /*-------------------------------------------------------------------------*/
1484
1485 static inline void
1486 itd_init(struct ehci_hcd *ehci, struct ehci_iso_stream *stream,
1487                 struct ehci_itd *itd)
1488 {
1489         int i;
1490
1491         /* it's been recently zeroed */
1492         itd->hw_next = EHCI_LIST_END(ehci);
1493         itd->hw_bufp [0] = stream->buf0;
1494         itd->hw_bufp [1] = stream->buf1;
1495         itd->hw_bufp [2] = stream->buf2;
1496
1497         for (i = 0; i < 8; i++)
1498                 itd->index[i] = -1;
1499
1500         /* All other fields are filled when scheduling */
1501 }
1502
1503 static inline void
1504 itd_patch(
1505         struct ehci_hcd         *ehci,
1506         struct ehci_itd         *itd,
1507         struct ehci_iso_sched   *iso_sched,
1508         unsigned                index,
1509         u16                     uframe
1510 )
1511 {
1512         struct ehci_iso_packet  *uf = &iso_sched->packet [index];
1513         unsigned                pg = itd->pg;
1514
1515         // BUG_ON (pg == 6 && uf->cross);
1516
1517         uframe &= 0x07;
1518         itd->index [uframe] = index;
1519
1520         itd->hw_transaction[uframe] = uf->transaction;
1521         itd->hw_transaction[uframe] |= cpu_to_hc32(ehci, pg << 12);
1522         itd->hw_bufp[pg] |= cpu_to_hc32(ehci, uf->bufp & ~(u32)0);
1523         itd->hw_bufp_hi[pg] |= cpu_to_hc32(ehci, (u32)(uf->bufp >> 32));
1524
1525         /* iso_frame_desc[].offset must be strictly increasing */
1526         if (unlikely (uf->cross)) {
1527                 u64     bufp = uf->bufp + 4096;
1528
1529                 itd->pg = ++pg;
1530                 itd->hw_bufp[pg] |= cpu_to_hc32(ehci, bufp & ~(u32)0);
1531                 itd->hw_bufp_hi[pg] |= cpu_to_hc32(ehci, (u32)(bufp >> 32));
1532         }
1533 }
1534
1535 static inline void
1536 itd_link (struct ehci_hcd *ehci, unsigned frame, struct ehci_itd *itd)
1537 {
1538         union ehci_shadow       *prev = &ehci->pshadow[frame];
1539         __hc32                  *hw_p = &ehci->periodic[frame];
1540         union ehci_shadow       here = *prev;
1541         __hc32                  type = 0;
1542
1543         /* skip any iso nodes which might belong to previous microframes */
1544         while (here.ptr) {
1545                 type = Q_NEXT_TYPE(ehci, *hw_p);
1546                 if (type == cpu_to_hc32(ehci, Q_TYPE_QH))
1547                         break;
1548                 prev = periodic_next_shadow(ehci, prev, type);
1549                 hw_p = shadow_next_periodic(ehci, &here, type);
1550                 here = *prev;
1551         }
1552
1553         itd->itd_next = here;
1554         itd->hw_next = *hw_p;
1555         prev->itd = itd;
1556         itd->frame = frame;
1557         wmb ();
1558         *hw_p = cpu_to_hc32(ehci, itd->itd_dma | Q_TYPE_ITD);
1559 }
1560
1561 /* fit urb's itds into the selected schedule slot; activate as needed */
1562 static void itd_link_urb(
1563         struct ehci_hcd         *ehci,
1564         struct urb              *urb,
1565         unsigned                mod,
1566         struct ehci_iso_stream  *stream
1567 )
1568 {
1569         int                     packet;
1570         unsigned                next_uframe, uframe, frame;
1571         struct ehci_iso_sched   *iso_sched = urb->hcpriv;
1572         struct ehci_itd         *itd;
1573
1574         next_uframe = stream->next_uframe & (mod - 1);
1575
1576         if (unlikely (list_empty(&stream->td_list))) {
1577                 ehci_to_hcd(ehci)->self.bandwidth_allocated
1578                                 += stream->bandwidth;
1579                 ehci_vdbg (ehci,
1580                         "schedule devp %s ep%d%s-iso period %d start %d.%d\n",
1581                         urb->dev->devpath, stream->bEndpointAddress & 0x0f,
1582                         (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out",
1583                         urb->interval,
1584                         next_uframe >> 3, next_uframe & 0x7);
1585         }
1586
1587         if (ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs == 0) {
1588                 if (ehci->amd_pll_fix == 1)
1589                         usb_amd_quirk_pll_disable();
1590         }
1591
1592         ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs++;
1593
1594         /* fill iTDs uframe by uframe */
1595         for (packet = 0, itd = NULL; packet < urb->number_of_packets; ) {
1596                 if (itd == NULL) {
1597                         /* ASSERT:  we have all necessary itds */
1598                         // BUG_ON (list_empty (&iso_sched->td_list));
1599
1600                         /* ASSERT:  no itds for this endpoint in this uframe */
1601
1602                         itd = list_entry (iso_sched->td_list.next,
1603                                         struct ehci_itd, itd_list);
1604                         list_move_tail (&itd->itd_list, &stream->td_list);
1605                         itd->stream = stream;
1606                         itd->urb = urb;
1607                         itd_init (ehci, stream, itd);
1608                 }
1609
1610                 uframe = next_uframe & 0x07;
1611                 frame = next_uframe >> 3;
1612
1613                 itd_patch(ehci, itd, iso_sched, packet, uframe);
1614
1615                 next_uframe += stream->interval;
1616                 next_uframe &= mod - 1;
1617                 packet++;
1618
1619                 /* link completed itds into the schedule */
1620                 if (((next_uframe >> 3) != frame)
1621                                 || packet == urb->number_of_packets) {
1622                         itd_link(ehci, frame & (ehci->periodic_size - 1), itd);
1623                         itd = NULL;
1624                 }
1625         }
1626         stream->next_uframe = next_uframe;
1627
1628         /* don't need that schedule data any more */
1629         iso_sched_free (stream, iso_sched);
1630         urb->hcpriv = stream;
1631
1632         ++ehci->isoc_count;
1633         enable_periodic(ehci);
1634 }
1635
1636 #define ISO_ERRS (EHCI_ISOC_BUF_ERR | EHCI_ISOC_BABBLE | EHCI_ISOC_XACTERR)
1637
1638 /* Process and recycle a completed ITD.  Return true iff its urb completed,
1639  * and hence its completion callback probably added things to the hardware
1640  * schedule.
1641  *
1642  * Note that we carefully avoid recycling this descriptor until after any
1643  * completion callback runs, so that it won't be reused quickly.  That is,
1644  * assuming (a) no more than two urbs per frame on this endpoint, and also
1645  * (b) only this endpoint's completions submit URBs.  It seems some silicon
1646  * corrupts things if you reuse completed descriptors very quickly...
1647  */
1648 static bool itd_complete(struct ehci_hcd *ehci, struct ehci_itd *itd)
1649 {
1650         struct urb                              *urb = itd->urb;
1651         struct usb_iso_packet_descriptor        *desc;
1652         u32                                     t;
1653         unsigned                                uframe;
1654         int                                     urb_index = -1;
1655         struct ehci_iso_stream                  *stream = itd->stream;
1656         struct usb_device                       *dev;
1657         bool                                    retval = false;
1658
1659         /* for each uframe with a packet */
1660         for (uframe = 0; uframe < 8; uframe++) {
1661                 if (likely (itd->index[uframe] == -1))
1662                         continue;
1663                 urb_index = itd->index[uframe];
1664                 desc = &urb->iso_frame_desc [urb_index];
1665
1666                 t = hc32_to_cpup(ehci, &itd->hw_transaction [uframe]);
1667                 itd->hw_transaction [uframe] = 0;
1668
1669                 /* report transfer status */
1670                 if (unlikely (t & ISO_ERRS)) {
1671                         urb->error_count++;
1672                         if (t & EHCI_ISOC_BUF_ERR)
1673                                 desc->status = usb_pipein (urb->pipe)
1674                                         ? -ENOSR  /* hc couldn't read */
1675                                         : -ECOMM; /* hc couldn't write */
1676                         else if (t & EHCI_ISOC_BABBLE)
1677                                 desc->status = -EOVERFLOW;
1678                         else /* (t & EHCI_ISOC_XACTERR) */
1679                                 desc->status = -EPROTO;
1680
1681                         /* HC need not update length with this error */
1682                         if (!(t & EHCI_ISOC_BABBLE)) {
1683                                 desc->actual_length = EHCI_ITD_LENGTH(t);
1684                                 urb->actual_length += desc->actual_length;
1685                         }
1686                 } else if (likely ((t & EHCI_ISOC_ACTIVE) == 0)) {
1687                         desc->status = 0;
1688                         desc->actual_length = EHCI_ITD_LENGTH(t);
1689                         urb->actual_length += desc->actual_length;
1690                 } else {
1691                         /* URB was too late */
1692                         urb->error_count++;
1693                 }
1694         }
1695
1696         /* handle completion now? */
1697         if (likely ((urb_index + 1) != urb->number_of_packets))
1698                 goto done;
1699
1700         /* ASSERT: it's really the last itd for this urb
1701         list_for_each_entry (itd, &stream->td_list, itd_list)
1702                 BUG_ON (itd->urb == urb);
1703          */
1704
1705         /* give urb back to the driver; completion often (re)submits */
1706         dev = urb->dev;
1707         ehci_urb_done(ehci, urb, 0);
1708         retval = true;
1709         urb = NULL;
1710
1711         --ehci->isoc_count;
1712         disable_periodic(ehci);
1713
1714         ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs--;
1715         if (ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs == 0) {
1716                 if (ehci->amd_pll_fix == 1)
1717                         usb_amd_quirk_pll_enable();
1718         }
1719
1720         if (unlikely(list_is_singular(&stream->td_list))) {
1721                 ehci_to_hcd(ehci)->self.bandwidth_allocated
1722                                 -= stream->bandwidth;
1723                 ehci_vdbg (ehci,
1724                         "deschedule devp %s ep%d%s-iso\n",
1725                         dev->devpath, stream->bEndpointAddress & 0x0f,
1726                         (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out");
1727         }
1728
1729 done:
1730         itd->urb = NULL;
1731
1732         /* Add to the end of the free list for later reuse */
1733         list_move_tail(&itd->itd_list, &stream->free_list);
1734
1735         /* Recycle the iTDs when the pipeline is empty (ep no longer in use) */
1736         if (list_empty(&stream->td_list)) {
1737                 list_splice_tail_init(&stream->free_list,
1738                                 &ehci->cached_itd_list);
1739                 start_free_itds(ehci);
1740         }
1741
1742         return retval;
1743 }
1744
1745 /*-------------------------------------------------------------------------*/
1746
1747 static int itd_submit (struct ehci_hcd *ehci, struct urb *urb,
1748         gfp_t mem_flags)
1749 {
1750         int                     status = -EINVAL;
1751         unsigned long           flags;
1752         struct ehci_iso_stream  *stream;
1753
1754         /* Get iso_stream head */
1755         stream = iso_stream_find (ehci, urb);
1756         if (unlikely (stream == NULL)) {
1757                 ehci_dbg (ehci, "can't get iso stream\n");
1758                 return -ENOMEM;
1759         }
1760         if (unlikely (urb->interval != stream->interval)) {
1761                 ehci_dbg (ehci, "can't change iso interval %d --> %d\n",
1762                         stream->interval, urb->interval);
1763                 goto done;
1764         }
1765
1766 #ifdef EHCI_URB_TRACE
1767         ehci_dbg (ehci,
1768                 "%s %s urb %p ep%d%s len %d, %d pkts %d uframes [%p]\n",
1769                 __func__, urb->dev->devpath, urb,
1770                 usb_pipeendpoint (urb->pipe),
1771                 usb_pipein (urb->pipe) ? "in" : "out",
1772                 urb->transfer_buffer_length,
1773                 urb->number_of_packets, urb->interval,
1774                 stream);
1775 #endif
1776
1777         /* allocate ITDs w/o locking anything */
1778         status = itd_urb_transaction (stream, ehci, urb, mem_flags);
1779         if (unlikely (status < 0)) {
1780                 ehci_dbg (ehci, "can't init itds\n");
1781                 goto done;
1782         }
1783
1784         /* schedule ... need to lock */
1785         spin_lock_irqsave (&ehci->lock, flags);
1786         if (unlikely(!HCD_HW_ACCESSIBLE(ehci_to_hcd(ehci)))) {
1787                 status = -ESHUTDOWN;
1788                 goto done_not_linked;
1789         }
1790         status = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
1791         if (unlikely(status))
1792                 goto done_not_linked;
1793         status = iso_stream_schedule(ehci, urb, stream);
1794         if (likely (status == 0))
1795                 itd_link_urb (ehci, urb, ehci->periodic_size << 3, stream);
1796         else
1797                 usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
1798  done_not_linked:
1799         spin_unlock_irqrestore (&ehci->lock, flags);
1800  done:
1801         return status;
1802 }
1803
1804 /*-------------------------------------------------------------------------*/
1805
1806 /*
1807  * "Split ISO TDs" ... used for USB 1.1 devices going through the
1808  * TTs in USB 2.0 hubs.  These need microframe scheduling.
1809  */
1810
1811 static inline void
1812 sitd_sched_init(
1813         struct ehci_hcd         *ehci,
1814         struct ehci_iso_sched   *iso_sched,
1815         struct ehci_iso_stream  *stream,
1816         struct urb              *urb
1817 )
1818 {
1819         unsigned        i;
1820         dma_addr_t      dma = urb->transfer_dma;
1821
1822         /* how many frames are needed for these transfers */
1823         iso_sched->span = urb->number_of_packets * stream->interval;
1824
1825         /* figure out per-frame sitd fields that we'll need later
1826          * when we fit new sitds into the schedule.
1827          */
1828         for (i = 0; i < urb->number_of_packets; i++) {
1829                 struct ehci_iso_packet  *packet = &iso_sched->packet [i];
1830                 unsigned                length;
1831                 dma_addr_t              buf;
1832                 u32                     trans;
1833
1834                 length = urb->iso_frame_desc [i].length & 0x03ff;
1835                 buf = dma + urb->iso_frame_desc [i].offset;
1836
1837                 trans = SITD_STS_ACTIVE;
1838                 if (((i + 1) == urb->number_of_packets)
1839                                 && !(urb->transfer_flags & URB_NO_INTERRUPT))
1840                         trans |= SITD_IOC;
1841                 trans |= length << 16;
1842                 packet->transaction = cpu_to_hc32(ehci, trans);
1843
1844                 /* might need to cross a buffer page within a td */
1845                 packet->bufp = buf;
1846                 packet->buf1 = (buf + length) & ~0x0fff;
1847                 if (packet->buf1 != (buf & ~(u64)0x0fff))
1848                         packet->cross = 1;
1849
1850                 /* OUT uses multiple start-splits */
1851                 if (stream->bEndpointAddress & USB_DIR_IN)
1852                         continue;
1853                 length = (length + 187) / 188;
1854                 if (length > 1) /* BEGIN vs ALL */
1855                         length |= 1 << 3;
1856                 packet->buf1 |= length;
1857         }
1858 }
1859
1860 static int
1861 sitd_urb_transaction (
1862         struct ehci_iso_stream  *stream,
1863         struct ehci_hcd         *ehci,
1864         struct urb              *urb,
1865         gfp_t                   mem_flags
1866 )
1867 {
1868         struct ehci_sitd        *sitd;
1869         dma_addr_t              sitd_dma;
1870         int                     i;
1871         struct ehci_iso_sched   *iso_sched;
1872         unsigned long           flags;
1873
1874         iso_sched = iso_sched_alloc (urb->number_of_packets, mem_flags);
1875         if (iso_sched == NULL)
1876                 return -ENOMEM;
1877
1878         sitd_sched_init(ehci, iso_sched, stream, urb);
1879
1880         /* allocate/init sITDs */
1881         spin_lock_irqsave (&ehci->lock, flags);
1882         for (i = 0; i < urb->number_of_packets; i++) {
1883
1884                 /* NOTE:  for now, we don't try to handle wraparound cases
1885                  * for IN (using sitd->hw_backpointer, like a FSTN), which
1886                  * means we never need two sitds for full speed packets.
1887                  */
1888
1889                 /*
1890                  * Use siTDs from the free list, but not siTDs that may
1891                  * still be in use by the hardware.
1892                  */
1893                 if (likely(!list_empty(&stream->free_list))) {
1894                         sitd = list_first_entry(&stream->free_list,
1895                                          struct ehci_sitd, sitd_list);
1896                         if (sitd->frame == ehci->now_frame)
1897                                 goto alloc_sitd;
1898                         list_del (&sitd->sitd_list);
1899                         sitd_dma = sitd->sitd_dma;
1900                 } else {
1901  alloc_sitd:
1902                         spin_unlock_irqrestore (&ehci->lock, flags);
1903                         sitd = dma_pool_alloc (ehci->sitd_pool, mem_flags,
1904                                         &sitd_dma);
1905                         spin_lock_irqsave (&ehci->lock, flags);
1906                         if (!sitd) {
1907                                 iso_sched_free(stream, iso_sched);
1908                                 spin_unlock_irqrestore(&ehci->lock, flags);
1909                                 return -ENOMEM;
1910                         }
1911                 }
1912
1913                 memset (sitd, 0, sizeof *sitd);
1914                 sitd->sitd_dma = sitd_dma;
1915                 sitd->frame = 9999;             /* an invalid value */
1916                 list_add (&sitd->sitd_list, &iso_sched->td_list);
1917         }
1918
1919         /* temporarily store schedule info in hcpriv */
1920         urb->hcpriv = iso_sched;
1921         urb->error_count = 0;
1922
1923         spin_unlock_irqrestore (&ehci->lock, flags);
1924         return 0;
1925 }
1926
1927 /*-------------------------------------------------------------------------*/
1928
1929 static inline void
1930 sitd_patch(
1931         struct ehci_hcd         *ehci,
1932         struct ehci_iso_stream  *stream,
1933         struct ehci_sitd        *sitd,
1934         struct ehci_iso_sched   *iso_sched,
1935         unsigned                index
1936 )
1937 {
1938         struct ehci_iso_packet  *uf = &iso_sched->packet [index];
1939         u64                     bufp = uf->bufp;
1940
1941         sitd->hw_next = EHCI_LIST_END(ehci);
1942         sitd->hw_fullspeed_ep = stream->address;
1943         sitd->hw_uframe = stream->splits;
1944         sitd->hw_results = uf->transaction;
1945         sitd->hw_backpointer = EHCI_LIST_END(ehci);
1946
1947         bufp = uf->bufp;
1948         sitd->hw_buf[0] = cpu_to_hc32(ehci, bufp);
1949         sitd->hw_buf_hi[0] = cpu_to_hc32(ehci, bufp >> 32);
1950
1951         sitd->hw_buf[1] = cpu_to_hc32(ehci, uf->buf1);
1952         if (uf->cross)
1953                 bufp += 4096;
1954         sitd->hw_buf_hi[1] = cpu_to_hc32(ehci, bufp >> 32);
1955         sitd->index = index;
1956 }
1957
1958 static inline void
1959 sitd_link (struct ehci_hcd *ehci, unsigned frame, struct ehci_sitd *sitd)
1960 {
1961         /* note: sitd ordering could matter (CSPLIT then SSPLIT) */
1962         sitd->sitd_next = ehci->pshadow [frame];
1963         sitd->hw_next = ehci->periodic [frame];
1964         ehci->pshadow [frame].sitd = sitd;
1965         sitd->frame = frame;
1966         wmb ();
1967         ehci->periodic[frame] = cpu_to_hc32(ehci, sitd->sitd_dma | Q_TYPE_SITD);
1968 }
1969
1970 /* fit urb's sitds into the selected schedule slot; activate as needed */
1971 static void sitd_link_urb(
1972         struct ehci_hcd         *ehci,
1973         struct urb              *urb,
1974         unsigned                mod,
1975         struct ehci_iso_stream  *stream
1976 )
1977 {
1978         int                     packet;
1979         unsigned                next_uframe;
1980         struct ehci_iso_sched   *sched = urb->hcpriv;
1981         struct ehci_sitd        *sitd;
1982
1983         next_uframe = stream->next_uframe;
1984
1985         if (list_empty(&stream->td_list)) {
1986                 /* usbfs ignores TT bandwidth */
1987                 ehci_to_hcd(ehci)->self.bandwidth_allocated
1988                                 += stream->bandwidth;
1989                 ehci_vdbg (ehci,
1990                         "sched devp %s ep%d%s-iso [%d] %dms/%04x\n",
1991                         urb->dev->devpath, stream->bEndpointAddress & 0x0f,
1992                         (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out",
1993                         (next_uframe >> 3) & (ehci->periodic_size - 1),
1994                         stream->interval, hc32_to_cpu(ehci, stream->splits));
1995         }
1996
1997         if (ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs == 0) {
1998                 if (ehci->amd_pll_fix == 1)
1999                         usb_amd_quirk_pll_disable();
2000         }
2001
2002         ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs++;
2003
2004         /* fill sITDs frame by frame */
2005         for (packet = 0, sitd = NULL;
2006                         packet < urb->number_of_packets;
2007                         packet++) {
2008
2009                 /* ASSERT:  we have all necessary sitds */
2010                 BUG_ON (list_empty (&sched->td_list));
2011
2012                 /* ASSERT:  no itds for this endpoint in this frame */
2013
2014                 sitd = list_entry (sched->td_list.next,
2015                                 struct ehci_sitd, sitd_list);
2016                 list_move_tail (&sitd->sitd_list, &stream->td_list);
2017                 sitd->stream = stream;
2018                 sitd->urb = urb;
2019
2020                 sitd_patch(ehci, stream, sitd, sched, packet);
2021                 sitd_link(ehci, (next_uframe >> 3) & (ehci->periodic_size - 1),
2022                                 sitd);
2023
2024                 next_uframe += stream->interval << 3;
2025         }
2026         stream->next_uframe = next_uframe & (mod - 1);
2027
2028         /* don't need that schedule data any more */
2029         iso_sched_free (stream, sched);
2030         urb->hcpriv = stream;
2031
2032         ++ehci->isoc_count;
2033         enable_periodic(ehci);
2034 }
2035
2036 /*-------------------------------------------------------------------------*/
2037
2038 #define SITD_ERRS (SITD_STS_ERR | SITD_STS_DBE | SITD_STS_BABBLE \
2039                                 | SITD_STS_XACT | SITD_STS_MMF)
2040
2041 /* Process and recycle a completed SITD.  Return true iff its urb completed,
2042  * and hence its completion callback probably added things to the hardware
2043  * schedule.
2044  *
2045  * Note that we carefully avoid recycling this descriptor until after any
2046  * completion callback runs, so that it won't be reused quickly.  That is,
2047  * assuming (a) no more than two urbs per frame on this endpoint, and also
2048  * (b) only this endpoint's completions submit URBs.  It seems some silicon
2049  * corrupts things if you reuse completed descriptors very quickly...
2050  */
2051 static bool sitd_complete(struct ehci_hcd *ehci, struct ehci_sitd *sitd)
2052 {
2053         struct urb                              *urb = sitd->urb;
2054         struct usb_iso_packet_descriptor        *desc;
2055         u32                                     t;
2056         int                                     urb_index = -1;
2057         struct ehci_iso_stream                  *stream = sitd->stream;
2058         struct usb_device                       *dev;
2059         bool                                    retval = false;
2060
2061         urb_index = sitd->index;
2062         desc = &urb->iso_frame_desc [urb_index];
2063         t = hc32_to_cpup(ehci, &sitd->hw_results);
2064
2065         /* report transfer status */
2066         if (unlikely(t & SITD_ERRS)) {
2067                 urb->error_count++;
2068                 if (t & SITD_STS_DBE)
2069                         desc->status = usb_pipein (urb->pipe)
2070                                 ? -ENOSR  /* hc couldn't read */
2071                                 : -ECOMM; /* hc couldn't write */
2072                 else if (t & SITD_STS_BABBLE)
2073                         desc->status = -EOVERFLOW;
2074                 else /* XACT, MMF, etc */
2075                         desc->status = -EPROTO;
2076         } else if (unlikely(t & SITD_STS_ACTIVE)) {
2077                 /* URB was too late */
2078                 urb->error_count++;
2079         } else {
2080                 desc->status = 0;
2081                 desc->actual_length = desc->length - SITD_LENGTH(t);
2082                 urb->actual_length += desc->actual_length;
2083         }
2084
2085         /* handle completion now? */
2086         if ((urb_index + 1) != urb->number_of_packets)
2087                 goto done;
2088
2089         /* ASSERT: it's really the last sitd for this urb
2090         list_for_each_entry (sitd, &stream->td_list, sitd_list)
2091                 BUG_ON (sitd->urb == urb);
2092          */
2093
2094         /* give urb back to the driver; completion often (re)submits */
2095         dev = urb->dev;
2096         ehci_urb_done(ehci, urb, 0);
2097         retval = true;
2098         urb = NULL;
2099
2100         --ehci->isoc_count;
2101         disable_periodic(ehci);
2102
2103         ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs--;
2104         if (ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs == 0) {
2105                 if (ehci->amd_pll_fix == 1)
2106                         usb_amd_quirk_pll_enable();
2107         }
2108
2109         if (list_is_singular(&stream->td_list)) {
2110                 ehci_to_hcd(ehci)->self.bandwidth_allocated
2111                                 -= stream->bandwidth;
2112                 ehci_vdbg (ehci,
2113                         "deschedule devp %s ep%d%s-iso\n",
2114                         dev->devpath, stream->bEndpointAddress & 0x0f,
2115                         (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out");
2116         }
2117
2118 done:
2119         sitd->urb = NULL;
2120
2121         /* Add to the end of the free list for later reuse */
2122         list_move_tail(&sitd->sitd_list, &stream->free_list);
2123
2124         /* Recycle the siTDs when the pipeline is empty (ep no longer in use) */
2125         if (list_empty(&stream->td_list)) {
2126                 list_splice_tail_init(&stream->free_list,
2127                                 &ehci->cached_sitd_list);
2128                 start_free_itds(ehci);
2129         }
2130
2131         return retval;
2132 }
2133
2134
2135 static int sitd_submit (struct ehci_hcd *ehci, struct urb *urb,
2136         gfp_t mem_flags)
2137 {
2138         int                     status = -EINVAL;
2139         unsigned long           flags;
2140         struct ehci_iso_stream  *stream;
2141
2142         /* Get iso_stream head */
2143         stream = iso_stream_find (ehci, urb);
2144         if (stream == NULL) {
2145                 ehci_dbg (ehci, "can't get iso stream\n");
2146                 return -ENOMEM;
2147         }
2148         if (urb->interval != stream->interval) {
2149                 ehci_dbg (ehci, "can't change iso interval %d --> %d\n",
2150                         stream->interval, urb->interval);
2151                 goto done;
2152         }
2153
2154 #ifdef EHCI_URB_TRACE
2155         ehci_dbg (ehci,
2156                 "submit %p dev%s ep%d%s-iso len %d\n",
2157                 urb, urb->dev->devpath,
2158                 usb_pipeendpoint (urb->pipe),
2159                 usb_pipein (urb->pipe) ? "in" : "out",
2160                 urb->transfer_buffer_length);
2161 #endif
2162
2163         /* allocate SITDs */
2164         status = sitd_urb_transaction (stream, ehci, urb, mem_flags);
2165         if (status < 0) {
2166                 ehci_dbg (ehci, "can't init sitds\n");
2167                 goto done;
2168         }
2169
2170         /* schedule ... need to lock */
2171         spin_lock_irqsave (&ehci->lock, flags);
2172         if (unlikely(!HCD_HW_ACCESSIBLE(ehci_to_hcd(ehci)))) {
2173                 status = -ESHUTDOWN;
2174                 goto done_not_linked;
2175         }
2176         status = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
2177         if (unlikely(status))
2178                 goto done_not_linked;
2179         status = iso_stream_schedule(ehci, urb, stream);
2180         if (status == 0)
2181                 sitd_link_urb (ehci, urb, ehci->periodic_size << 3, stream);
2182         else
2183                 usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
2184  done_not_linked:
2185         spin_unlock_irqrestore (&ehci->lock, flags);
2186  done:
2187         return status;
2188 }
2189
2190 /*-------------------------------------------------------------------------*/
2191
2192 static void scan_isoc(struct ehci_hcd *ehci)
2193 {
2194         unsigned        uf, now_frame, frame;
2195         unsigned        fmask = ehci->periodic_size - 1;
2196         bool            modified, live;
2197
2198         /*
2199          * When running, scan from last scan point up to "now"
2200          * else clean up by scanning everything that's left.
2201          * Touches as few pages as possible:  cache-friendly.
2202          */
2203         if (ehci->rh_state >= EHCI_RH_RUNNING) {
2204                 uf = ehci_read_frame_index(ehci);
2205                 now_frame = (uf >> 3) & fmask;
2206                 live = true;
2207         } else  {
2208                 now_frame = (ehci->last_iso_frame - 1) & fmask;
2209                 live = false;
2210         }
2211         ehci->now_frame = now_frame;
2212
2213         frame = ehci->last_iso_frame;
2214         for (;;) {
2215                 union ehci_shadow       q, *q_p;
2216                 __hc32                  type, *hw_p;
2217
2218 restart:
2219                 /* scan each element in frame's queue for completions */
2220                 q_p = &ehci->pshadow [frame];
2221                 hw_p = &ehci->periodic [frame];
2222                 q.ptr = q_p->ptr;
2223                 type = Q_NEXT_TYPE(ehci, *hw_p);
2224                 modified = false;
2225
2226                 while (q.ptr != NULL) {
2227                         switch (hc32_to_cpu(ehci, type)) {
2228                         case Q_TYPE_ITD:
2229                                 /* If this ITD is still active, leave it for
2230                                  * later processing ... check the next entry.
2231                                  * No need to check for activity unless the
2232                                  * frame is current.
2233                                  */
2234                                 if (frame == now_frame && live) {
2235                                         rmb();
2236                                         for (uf = 0; uf < 8; uf++) {
2237                                                 if (q.itd->hw_transaction[uf] &
2238                                                             ITD_ACTIVE(ehci))
2239                                                         break;
2240                                         }
2241                                         if (uf < 8) {
2242                                                 q_p = &q.itd->itd_next;
2243                                                 hw_p = &q.itd->hw_next;
2244                                                 type = Q_NEXT_TYPE(ehci,
2245                                                         q.itd->hw_next);
2246                                                 q = *q_p;
2247                                                 break;
2248                                         }
2249                                 }
2250
2251                                 /* Take finished ITDs out of the schedule
2252                                  * and process them:  recycle, maybe report
2253                                  * URB completion.  HC won't cache the
2254                                  * pointer for much longer, if at all.
2255                                  */
2256                                 *q_p = q.itd->itd_next;
2257                                 if (!ehci->use_dummy_qh ||
2258                                     q.itd->hw_next != EHCI_LIST_END(ehci))
2259                                         *hw_p = q.itd->hw_next;
2260                                 else
2261                                         *hw_p = ehci->dummy->qh_dma;
2262                                 type = Q_NEXT_TYPE(ehci, q.itd->hw_next);
2263                                 wmb();
2264                                 modified = itd_complete (ehci, q.itd);
2265                                 q = *q_p;
2266                                 break;
2267                         case Q_TYPE_SITD:
2268                                 /* If this SITD is still active, leave it for
2269                                  * later processing ... check the next entry.
2270                                  * No need to check for activity unless the
2271                                  * frame is current.
2272                                  */
2273                                 if (((frame == now_frame) ||
2274                                      (((frame + 1) & fmask) == now_frame))
2275                                     && live
2276                                     && (q.sitd->hw_results &
2277                                         SITD_ACTIVE(ehci))) {
2278
2279                                         q_p = &q.sitd->sitd_next;
2280                                         hw_p = &q.sitd->hw_next;
2281                                         type = Q_NEXT_TYPE(ehci,
2282                                                         q.sitd->hw_next);
2283                                         q = *q_p;
2284                                         break;
2285                                 }
2286
2287                                 /* Take finished SITDs out of the schedule
2288                                  * and process them:  recycle, maybe report
2289                                  * URB completion.
2290                                  */
2291                                 *q_p = q.sitd->sitd_next;
2292                                 if (!ehci->use_dummy_qh ||
2293                                     q.sitd->hw_next != EHCI_LIST_END(ehci))
2294                                         *hw_p = q.sitd->hw_next;
2295                                 else
2296                                         *hw_p = ehci->dummy->qh_dma;
2297                                 type = Q_NEXT_TYPE(ehci, q.sitd->hw_next);
2298                                 wmb();
2299                                 modified = sitd_complete (ehci, q.sitd);
2300                                 q = *q_p;
2301                                 break;
2302                         default:
2303                                 ehci_dbg(ehci, "corrupt type %d frame %d shadow %p\n",
2304                                         type, frame, q.ptr);
2305                                 // BUG ();
2306                                 /* FALL THROUGH */
2307                         case Q_TYPE_QH:
2308                         case Q_TYPE_FSTN:
2309                                 /* End of the iTDs and siTDs */
2310                                 q.ptr = NULL;
2311                                 break;
2312                         }
2313
2314                         /* assume completion callbacks modify the queue */
2315                         if (unlikely(modified && ehci->isoc_count > 0))
2316                                 goto restart;
2317                 }
2318
2319                 /* Stop when we have reached the current frame */
2320                 if (frame == now_frame)
2321                         break;
2322
2323                 /* The last frame may still have active siTDs */
2324                 ehci->last_iso_frame = frame;
2325                 frame = (frame + 1) & fmask;
2326         }
2327 }