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

   1 /*
   2  * Copyright (C) 2001-2004 by David Brownell
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License as published by the
   6  * Free Software Foundation; either version 2 of the License, or (at your
   7  * option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  11  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software Foundation,
  16  * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17  */
  18
  19 /* this file is part of ehci-hcd.c */
  20
  21 /*-------------------------------------------------------------------------*/
  22
  23 /*
  24  * EHCI hardware queue manipulation ... the core.  QH/QTD manipulation.
  25  *
  26  * Control, bulk, and interrupt traffic all use "qh" lists.  They list "qtd"
  27  * entries describing USB transactions, max 16-20kB/entry (with 4kB-aligned
  28  * buffers needed for the larger number).  We use one QH per endpoint, queue
  29  * multiple urbs (all three types) per endpoint.  URBs may need several qtds.
  30  *
  31  * ISO traffic uses "ISO TD" (itd, and sitd) records, and (along with
  32  * interrupts) needs careful scheduling.  Performance improvements can be
  33  * an ongoing challenge.  That's in "ehci-sched.c".
  34  *
  35  * USB 1.1 devices are handled (a) by "companion" OHCI or UHCI root hubs,
  36  * or otherwise through transaction translators (TTs) in USB 2.0 hubs using
  37  * (b) special fields in qh entries or (c) split iso entries.  TTs will
  38  * buffer low/full speed data so the host collects it at high speed.
  39  */
  40
  41 /*-------------------------------------------------------------------------*/
  42
  43 /* fill a qtd, returning how much of the buffer we were able to queue up */
  44
  45 static int
  46 qtd_fill(struct ehci_hcd *ehci, struct ehci_qtd *qtd, dma_addr_t buf,
  47                   size_t len, int token, int maxpacket)
  48 {
  49         int     i, count;
  50         u64     addr = buf;
  51
  52         /* one buffer entry per 4K ... first might be short or unaligned */
  53         qtd->hw_buf[0] = cpu_to_hc32(ehci, (u32)addr);
  54         qtd->hw_buf_hi[0] = cpu_to_hc32(ehci, (u32)(addr >> 32));
  55         count = 0x1000 - (buf & 0x0fff);        /* rest of that page */
  56         if (likely (len < count))               /* ... iff needed */
  57                 count = len;
  58         else {
  59                 buf +=  0x1000;
  60                 buf &= ~0x0fff;
  61
  62                 /* per-qtd limit: from 16K to 20K (best alignment) */
  63                 for (i = 1; count < len && i < 5; i++) {
  64                         addr = buf;
  65                         qtd->hw_buf[i] = cpu_to_hc32(ehci, (u32)addr);
  66                         qtd->hw_buf_hi[i] = cpu_to_hc32(ehci,
  67                                         (u32)(addr >> 32));
  68                         buf += 0x1000;
  69                         if ((count + 0x1000) < len)
  70                                 count += 0x1000;
  71                         else
  72                                 count = len;
  73                 }
  74
  75                 /* short packets may only terminate transfers */
  76                 if (count != len)
  77                         count -= (count % maxpacket);
  78         }
  79         qtd->hw_token = cpu_to_hc32(ehci, (count << 16) | token);
  80         qtd->length = count;
  81
  82         return count;
  83 }
  84
  85 /*-------------------------------------------------------------------------*/
  86
  87 static inline void
  88 qh_update (struct ehci_hcd *ehci, struct ehci_qh *qh, struct ehci_qtd *qtd)
  89 {
  90         /* writes to an active overlay are unsafe */
  91         BUG_ON(qh->qh_state != QH_STATE_IDLE);
  92
  93         qh->hw_qtd_next = QTD_NEXT(ehci, qtd->qtd_dma);
  94         qh->hw_alt_next = EHCI_LIST_END(ehci);
  95
  96         /* Except for control endpoints, we make hardware maintain data
  97          * toggle (like OHCI) ... here (re)initialize the toggle in the QH,
  98          * and set the pseudo-toggle in udev. Only usb_clear_halt() will
  99          * ever clear it.
 100          */
 101         if (!(qh->hw_info1 & cpu_to_hc32(ehci, 1 << 14))) {
 102                 unsigned        is_out, epnum;
 103
 104                 is_out = !(qtd->hw_token & cpu_to_hc32(ehci, 1 << 8));
 105                 epnum = (hc32_to_cpup(ehci, &qh->hw_info1) >> 8) & 0x0f;
 106                 if (unlikely (!usb_gettoggle (qh->dev, epnum, is_out))) {
 107                         qh->hw_token &= ~cpu_to_hc32(ehci, QTD_TOGGLE);
 108                         usb_settoggle (qh->dev, epnum, is_out, 1);
 109                 }
 110         }
 111
 112         /* HC must see latest qtd and qh data before we clear ACTIVE+HALT */
 113         wmb ();
 114         qh->hw_token &= cpu_to_hc32(ehci, QTD_TOGGLE | QTD_STS_PING);
 115 }
 116
 117 /* if it weren't for a common silicon quirk (writing the dummy into the qh
 118  * overlay, so qh->hw_token wrongly becomes inactive/halted), only fault
 119  * recovery (including urb dequeue) would need software changes to a QH...
 120  */
 121 static void
 122 qh_refresh (struct ehci_hcd *ehci, struct ehci_qh *qh)
 123 {
 124         struct ehci_qtd *qtd;
 125
 126         if (list_empty (&qh->qtd_list))
 127                 qtd = qh->dummy;
 128         else {
 129                 qtd = list_entry (qh->qtd_list.next,
 130                                 struct ehci_qtd, qtd_list);
 131                 /* first qtd may already be partially processed */
 132                 if (cpu_to_hc32(ehci, qtd->qtd_dma) == qh->hw_current)
 133                         qtd = NULL;
 134         }
 135
 136         if (qtd)
 137                 qh_update (ehci, qh, qtd);
 138 }
 139
 140 /*-------------------------------------------------------------------------*/
 141
 142 static int qtd_copy_status (
 143         struct ehci_hcd *ehci,
 144         struct urb *urb,
 145         size_t length,
 146         u32 token
 147 )
 148 {
 149         int     status = -EINPROGRESS;
 150
 151         /* count IN/OUT bytes, not SETUP (even short packets) */
 152         if (likely (QTD_PID (token) != 2))
 153                 urb->actual_length += length - QTD_LENGTH (token);
 154
 155         /* don't modify error codes */
 156         if (unlikely(urb->unlinked))
 157                 return status;
 158
 159         /* force cleanup after short read; not always an error */
 160         if (unlikely (IS_SHORT_READ (token)))
 161                 status = -EREMOTEIO;
 162
 163         /* serious "can't proceed" faults reported by the hardware */
 164         if (token & QTD_STS_HALT) {
 165                 if (token & QTD_STS_BABBLE) {
 166                         /* FIXME "must" disable babbling device's port too */
 167                         status = -EOVERFLOW;
 168                 } else if (token & QTD_STS_MMF) {
 169                         /* fs/ls interrupt xfer missed the complete-split */
 170                         status = -EPROTO;
 171                 } else if (token & QTD_STS_DBE) {
 172                         status = (QTD_PID (token) == 1) /* IN ? */
 173                                 ? -ENOSR  /* hc couldn't read data */
 174                                 : -ECOMM; /* hc couldn't write data */
 175                 } else if (token & QTD_STS_XACT) {
 176                         /* timeout, bad crc, wrong PID, etc; retried */
 177                         if (QTD_CERR (token))
 178                                 status = -EPIPE;
 179                         else {
 180                                 ehci_dbg (ehci, "devpath %s ep%d%s 3strikes\n",
 181                                         urb->dev->devpath,
 182                                         usb_pipeendpoint (urb->pipe),
 183                                         usb_pipein (urb->pipe) ? "in" : "out");
 184                                 status = -EPROTO;
 185                         }
 186                 /* CERR nonzero + no errors + halt --> stall */
 187                 } else if (QTD_CERR (token))
 188                         status = -EPIPE;
 189                 else    /* unknown */
 190                         status = -EPROTO;
 191
 192                 ehci_vdbg (ehci,
 193                         "dev%d ep%d%s qtd token %08x --> status %d\n",
 194                         usb_pipedevice (urb->pipe),
 195                         usb_pipeendpoint (urb->pipe),
 196                         usb_pipein (urb->pipe) ? "in" : "out",
 197                         token, status);
 198
 199                 /* if async CSPLIT failed, try cleaning out the TT buffer */
 200                 if (status != -EPIPE
 201                                 && urb->dev->tt
 202                                 && !usb_pipeint(urb->pipe)
 203                                 && ((token & QTD_STS_MMF) != 0
 204                                         || QTD_CERR(token) == 0)
 205                                 && (!ehci_is_TDI(ehci)
 206                                         || urb->dev->tt->hub !=
 207                                            ehci_to_hcd(ehci)->self.root_hub)) {
 208 #ifdef DEBUG
 209                         struct usb_device *tt = urb->dev->tt->hub;
 210                         dev_dbg (&tt->dev,
 211                                 "clear tt buffer port %d, a%d ep%d t%08x\n",
 212                                 urb->dev->ttport, urb->dev->devnum,
 213                                 usb_pipeendpoint (urb->pipe), token);
 214 #endif /* DEBUG */
 215                         /* REVISIT ARC-derived cores don't clear the root
 216                          * hub TT buffer in this way...
 217                          */
 218                         usb_hub_clear_tt_buffer(urb);
 219                 }
 220         }
 221
 222         return status;
 223 }
 224
 225 static void
 226 ehci_urb_done(struct ehci_hcd *ehci, struct urb *urb, int status)
 227 __releases(ehci->lock)
 228 __acquires(ehci->lock)
 229 {
 230         if (likely (urb->hcpriv != NULL)) {
 231                 struct ehci_qh  *qh = (struct ehci_qh *) urb->hcpriv;
 232
 233                 /* S-mask in a QH means it's an interrupt urb */
 234                 if ((qh->hw_info2 & cpu_to_hc32(ehci, QH_SMASK)) != 0) {
 235
 236                         /* ... update hc-wide periodic stats (for usbfs) */
 237                         ehci_to_hcd(ehci)->self.bandwidth_int_reqs--;
 238                 }
 239                 qh_put (qh);
 240         }
 241
 242         if (unlikely(urb->unlinked)) {
 243                 COUNT(ehci->stats.unlink);
 244         } else {
 245                 /* report non-error and short read status as zero */
 246                 if (status == -EINPROGRESS || status == -EREMOTEIO)
 247                         status = 0;
 248                 COUNT(ehci->stats.complete);
 249         }
 250
 251 #ifdef EHCI_URB_TRACE
 252         ehci_dbg (ehci,
 253                 "%s %s urb %p ep%d%s status %d len %d/%d\n",
 254                 __func__, urb->dev->devpath, urb,
 255                 usb_pipeendpoint (urb->pipe),
 256                 usb_pipein (urb->pipe) ? "in" : "out",
 257                 status,
 258                 urb->actual_length, urb->transfer_buffer_length);
 259 #endif
 260
 261         /* complete() can reenter this HCD */
 262         usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
 263         spin_unlock (&ehci->lock);
 264         usb_hcd_giveback_urb(ehci_to_hcd(ehci), urb, status);
 265         spin_lock (&ehci->lock);
 266 }
 267
 268 static void start_unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh);
 269 static void unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh);
 270
 271 static void intr_deschedule (struct ehci_hcd *ehci, struct ehci_qh *qh);
 272 static int qh_schedule (struct ehci_hcd *ehci, struct ehci_qh *qh);
 273
 274 /*
 275  * Process and free completed qtds for a qh, returning URBs to drivers.
 276  * Chases up to qh->hw_current.  Returns number of completions called,
 277  * indicating how much "real" work we did.
 278  */
 279 static unsigned
 280 qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
 281 {
 282         struct ehci_qtd         *last = NULL, *end = qh->dummy;
 283         struct list_head        *entry, *tmp;
 284         int                     last_status = -EINPROGRESS;
 285         int                     stopped;
 286         unsigned                count = 0;
 287         u8                      state;
 288         __le32                  halt = HALT_BIT(ehci);
 289
 290         if (unlikely (list_empty (&qh->qtd_list)))
 291                 return count;
 292
 293         /* completions (or tasks on other cpus) must never clobber HALT
 294          * till we've gone through and cleaned everything up, even when
 295          * they add urbs to this qh's queue or mark them for unlinking.
 296          *
 297          * NOTE:  unlinking expects to be done in queue order.
 298          */
 299         state = qh->qh_state;
 300         qh->qh_state = QH_STATE_COMPLETING;
 301         stopped = (state == QH_STATE_IDLE);
 302
 303         /* remove de-activated QTDs from front of queue.
 304          * after faults (including short reads), cleanup this urb
 305          * then let the queue advance.
 306          * if queue is stopped, handles unlinks.
 307          */
 308         list_for_each_safe (entry, tmp, &qh->qtd_list) {
 309                 struct ehci_qtd *qtd;
 310                 struct urb      *urb;
 311                 u32             token = 0;
 312
 313                 qtd = list_entry (entry, struct ehci_qtd, qtd_list);
 314                 urb = qtd->urb;
 315
 316                 /* clean up any state from previous QTD ...*/
 317                 if (last) {
 318                         if (likely (last->urb != urb)) {
 319                                 ehci_urb_done(ehci, last->urb, last_status);
 320                                 count++;
 321                                 last_status = -EINPROGRESS;
 322                         }
 323                         ehci_qtd_free (ehci, last);
 324                         last = NULL;
 325                 }
 326
 327                 /* ignore urbs submitted during completions we reported */
 328                 if (qtd == end)
 329                         break;
 330
 331                 /* hardware copies qtd out of qh overlay */
 332                 rmb ();
 333                 token = hc32_to_cpu(ehci, qtd->hw_token);
 334
 335                 /* always clean up qtds the hc de-activated */
 336  retry_xacterr:
 337                 if ((token & QTD_STS_ACTIVE) == 0) {
 338
 339                         /* on STALL, error, and short reads this urb must
 340                          * complete and all its qtds must be recycled.
 341                          */
 342                         if ((token & QTD_STS_HALT) != 0) {
 343
 344                                 /* retry transaction errors until we
 345                                  * reach the software xacterr limit
 346                                  */
 347                                 if ((token & QTD_STS_XACT) &&
 348                                                 QTD_CERR(token) == 0 &&
 349                                                 --qh->xacterrs > 0 &&
 350                                                 !urb->unlinked) {
 351                                         ehci_dbg(ehci,
 352         "detected XactErr len %zu/%zu retry %d\n",
 353         qtd->length - QTD_LENGTH(token), qtd->length,
 354         QH_XACTERR_MAX - qh->xacterrs);
 355
 356                                         /* reset the token in the qtd and the
 357                                          * qh overlay (which still contains
 358                                          * the qtd) so that we pick up from
 359                                          * where we left off
 360                                          */
 361                                         token &= ~QTD_STS_HALT;
 362                                         token |= QTD_STS_ACTIVE |
 363                                                         (EHCI_TUNE_CERR << 10);
 364                                         qtd->hw_token = cpu_to_hc32(ehci,
 365                                                         token);
 366                                         wmb();
 367                                         qh->hw_token = cpu_to_hc32(ehci, token);
 368                                         goto retry_xacterr;
 369                                 }
 370                                 stopped = 1;
 371
 372                         /* magic dummy for some short reads; qh won't advance.
 373                          * that silicon quirk can kick in with this dummy too.
 374                          *
 375                          * other short reads won't stop the queue, including
 376                          * control transfers (status stage handles that) or
 377                          * most other single-qtd reads ... the queue stops if
 378                          * URB_SHORT_NOT_OK was set so the driver submitting
 379                          * the urbs could clean it up.
 380                          */
 381                         } else if (IS_SHORT_READ (token)
 382                                         && !(qtd->hw_alt_next
 383                                                 & EHCI_LIST_END(ehci))) {
 384                                 stopped = 1;
 385                                 goto halt;
 386                         }
 387
 388                 /* stop scanning when we reach qtds the hc is using */
 389                 } else if (likely (!stopped
 390                                 && HC_IS_RUNNING (ehci_to_hcd(ehci)->state))) {
 391                         break;
 392
 393                 /* scan the whole queue for unlinks whenever it stops */
 394                 } else {
 395                         stopped = 1;
 396
 397                         /* cancel everything if we halt, suspend, etc */
 398                         if (!HC_IS_RUNNING(ehci_to_hcd(ehci)->state))
 399                                 last_status = -ESHUTDOWN;
 400
 401                         /* this qtd is active; skip it unless a previous qtd
 402                          * for its urb faulted, or its urb was canceled.
 403                          */
 404                         else if (last_status == -EINPROGRESS && !urb->unlinked)
 405                                 continue;
 406
 407                         /* qh unlinked; token in overlay may be most current */
 408                         if (state == QH_STATE_IDLE
 409                                         && cpu_to_hc32(ehci, qtd->qtd_dma)
 410                                                 == qh->hw_current)
 411                                 token = hc32_to_cpu(ehci, qh->hw_token);
 412
 413                         /* force halt for unlinked or blocked qh, so we'll
 414                          * patch the qh later and so that completions can't
 415                          * activate it while we "know" it's stopped.
 416                          */
 417                         if ((halt & qh->hw_token) == 0) {
 418 halt:
 419                                 qh->hw_token |= halt;
 420                                 wmb ();
 421                         }
 422                 }
 423
 424                 /* unless we already know the urb's status, collect qtd status
 425                  * and update count of bytes transferred.  in common short read
 426                  * cases with only one data qtd (including control transfers),
 427                  * queue processing won't halt.  but with two or more qtds (for
 428                  * example, with a 32 KB transfer), when the first qtd gets a
 429                  * short read the second must be removed by hand.
 430                  */
 431                 if (last_status == -EINPROGRESS) {
 432                         last_status = qtd_copy_status(ehci, urb,
 433                                         qtd->length, token);
 434                         if (last_status == -EREMOTEIO
 435                                         && (qtd->hw_alt_next
 436                                                 & EHCI_LIST_END(ehci)))
 437                                 last_status = -EINPROGRESS;
 438                 }
 439
 440                 /* if we're removing something not at the queue head,
 441                  * patch the hardware queue pointer.
 442                  */
 443                 if (stopped && qtd->qtd_list.prev != &qh->qtd_list) {
 444                         last = list_entry (qtd->qtd_list.prev,
 445                                         struct ehci_qtd, qtd_list);
 446                         last->hw_next = qtd->hw_next;
 447                 }
 448
 449                 /* remove qtd; it's recycled after possible urb completion */
 450                 list_del (&qtd->qtd_list);
 451                 last = qtd;
 452
 453                 /* reinit the xacterr counter for the next qtd */
 454                 qh->xacterrs = QH_XACTERR_MAX;
 455         }
 456
 457         /* last urb's completion might still need calling */
 458         if (likely (last != NULL)) {
 459                 ehci_urb_done(ehci, last->urb, last_status);
 460                 count++;
 461                 ehci_qtd_free (ehci, last);
 462         }
 463
 464         /* restore original state; caller must unlink or relink */
 465         qh->qh_state = state;
 466
 467         /* be sure the hardware's done with the qh before refreshing
 468          * it after fault cleanup, or recovering from silicon wrongly
 469          * overlaying the dummy qtd (which reduces DMA chatter).
 470          */
 471         if (stopped != 0 || qh->hw_qtd_next == EHCI_LIST_END(ehci)) {
 472                 switch (state) {
 473                 case QH_STATE_IDLE:
 474                         qh_refresh(ehci, qh);
 475                         break;
 476                 case QH_STATE_LINKED:
 477                         /* We won't refresh a QH that's linked (after the HC
 478                          * stopped the queue).  That avoids a race:
 479                          *  - HC reads first part of QH;
 480                          *  - CPU updates that first part and the token;
 481                          *  - HC reads rest of that QH, including token
 482                          * Result:  HC gets an inconsistent image, and then
 483                          * DMAs to/from the wrong memory (corrupting it).
 484                          *
 485                          * That should be rare for interrupt transfers,
 486                          * except maybe high bandwidth ...
 487                          */
 488                         if ((cpu_to_hc32(ehci, QH_SMASK)
 489                                         & qh->hw_info2) != 0) {
 490                                 intr_deschedule (ehci, qh);
 491                                 (void) qh_schedule (ehci, qh);
 492                         } else
 493                                 unlink_async (ehci, qh);
 494                         break;
 495                 /* otherwise, unlink already started */
 496                 }
 497         }
 498
 499         return count;
 500 }
 501
 502 /*-------------------------------------------------------------------------*/
 503
 504 // high bandwidth multiplier, as encoded in highspeed endpoint descriptors
 505 #define hb_mult(wMaxPacketSize) (1 + (((wMaxPacketSize) >> 11) & 0x03))
 506 // ... and packet size, for any kind of endpoint descriptor
 507 #define max_packet(wMaxPacketSize) ((wMaxPacketSize) & 0x07ff)
 508
 509 /*
 510  * reverse of qh_urb_transaction:  free a list of TDs.
 511  * used for cleanup after errors, before HC sees an URB's TDs.
 512  */
 513 static void qtd_list_free (
 514         struct ehci_hcd         *ehci,
 515         struct urb              *urb,
 516         struct list_head        *qtd_list
 517 ) {
 518         struct list_head        *entry, *temp;
 519
 520         list_for_each_safe (entry, temp, qtd_list) {
 521                 struct ehci_qtd *qtd;
 522
 523                 qtd = list_entry (entry, struct ehci_qtd, qtd_list);
 524                 list_del (&qtd->qtd_list);
 525                 ehci_qtd_free (ehci, qtd);
 526         }
 527 }
 528
 529 /*
 530  * create a list of filled qtds for this URB; won't link into qh.
 531  */
 532 static struct list_head *
 533 qh_urb_transaction (
 534         struct ehci_hcd         *ehci,
 535         struct urb              *urb,
 536         struct list_head        *head,
 537         gfp_t                   flags
 538 ) {
 539         struct ehci_qtd         *qtd, *qtd_prev;
 540         dma_addr_t              buf;
 541         int                     len, maxpacket;
 542         int                     is_input;
 543         u32                     token;
 544
 545         /*
 546          * URBs map to sequences of QTDs:  one logical transaction
 547          */
 548         qtd = ehci_qtd_alloc (ehci, flags);
 549         if (unlikely (!qtd))
 550                 return NULL;
 551         list_add_tail (&qtd->qtd_list, head);
 552         qtd->urb = urb;
 553
 554         token = QTD_STS_ACTIVE;
 555         token |= (EHCI_TUNE_CERR << 10);
 556         /* for split transactions, SplitXState initialized to zero */
 557
 558         len = urb->transfer_buffer_length;
 559         is_input = usb_pipein (urb->pipe);
 560         if (usb_pipecontrol (urb->pipe)) {
 561                 /* SETUP pid */
 562                 qtd_fill(ehci, qtd, urb->setup_dma,
 563                                 sizeof (struct usb_ctrlrequest),
 564                                 token | (2 /* "setup" */ << 8), 8);
 565
 566                 /* ... and always at least one more pid */
 567                 token ^= QTD_TOGGLE;
 568                 qtd_prev = qtd;
 569                 qtd = ehci_qtd_alloc (ehci, flags);
 570                 if (unlikely (!qtd))
 571                         goto cleanup;
 572                 qtd->urb = urb;
 573                 qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
 574                 list_add_tail (&qtd->qtd_list, head);
 575
 576                 /* for zero length DATA stages, STATUS is always IN */
 577                 if (len == 0)
 578                         token |= (1 /* "in" */ << 8);
 579         }
 580
 581         /*
 582          * data transfer stage:  buffer setup
 583          */
 584         buf = urb->transfer_dma;
 585
 586         if (is_input)
 587                 token |= (1 /* "in" */ << 8);
 588         /* else it's already initted to "out" pid (0 << 8) */
 589
 590         maxpacket = max_packet(usb_maxpacket(urb->dev, urb->pipe, !is_input));
 591
 592         /*
 593          * buffer gets wrapped in one or more qtds;
 594          * last one may be "short" (including zero len)
 595          * and may serve as a control status ack
 596          */
 597         for (;;) {
 598                 int this_qtd_len;
 599
 600                 this_qtd_len = qtd_fill(ehci, qtd, buf, len, token, maxpacket);
 601                 len -= this_qtd_len;
 602                 buf += this_qtd_len;
 603
 604                 /*
 605                  * short reads advance to a "magic" dummy instead of the next
 606                  * qtd ... that forces the queue to stop, for manual cleanup.
 607                  * (this will usually be overridden later.)
 608                  */
 609                 if (is_input)
 610                         qtd->hw_alt_next = ehci->async->hw_alt_next;
 611
 612                 /* qh makes control packets use qtd toggle; maybe switch it */
 613                 if ((maxpacket & (this_qtd_len + (maxpacket - 1))) == 0)
 614                         token ^= QTD_TOGGLE;
 615
 616                 if (likely (len <= 0))
 617                         break;
 618
 619                 qtd_prev = qtd;
 620                 qtd = ehci_qtd_alloc (ehci, flags);
 621                 if (unlikely (!qtd))
 622                         goto cleanup;
 623                 qtd->urb = urb;
 624                 qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
 625                 list_add_tail (&qtd->qtd_list, head);
 626         }
 627
 628         /*
 629          * unless the caller requires manual cleanup after short reads,
 630          * have the alt_next mechanism keep the queue running after the
 631          * last data qtd (the only one, for control and most other cases).
 632          */
 633         if (likely ((urb->transfer_flags & URB_SHORT_NOT_OK) == 0
 634                                 || usb_pipecontrol (urb->pipe)))
 635                 qtd->hw_alt_next = EHCI_LIST_END(ehci);
 636
 637         /*
 638          * control requests may need a terminating data "status" ack;
 639          * bulk ones may need a terminating short packet (zero length).
 640          */
 641         if (likely (urb->transfer_buffer_length != 0)) {
 642                 int     one_more = 0;
 643
 644                 if (usb_pipecontrol (urb->pipe)) {
 645                         one_more = 1;
 646                         token ^= 0x0100;        /* "in" <--> "out"  */
 647                         token |= QTD_TOGGLE;    /* force DATA1 */
 648                 } else if (usb_pipebulk (urb->pipe)
 649                                 && (urb->transfer_flags & URB_ZERO_PACKET)
 650                                 && !(urb->transfer_buffer_length % maxpacket)) {
 651                         one_more = 1;
 652                 }
 653                 if (one_more) {
 654                         qtd_prev = qtd;
 655                         qtd = ehci_qtd_alloc (ehci, flags);
 656                         if (unlikely (!qtd))
 657                                 goto cleanup;
 658                         qtd->urb = urb;
 659                         qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
 660                         list_add_tail (&qtd->qtd_list, head);
 661
 662                         /* never any data in such packets */
 663                         qtd_fill(ehci, qtd, 0, 0, token, 0);
 664                 }
 665         }
 666
 667         /* by default, enable interrupt on urb completion */
 668         if (likely (!(urb->transfer_flags & URB_NO_INTERRUPT)))
 669                 qtd->hw_token |= cpu_to_hc32(ehci, QTD_IOC);
 670         return head;
 671
 672 cleanup:
 673         qtd_list_free (ehci, urb, head);
 674         return NULL;
 675 }
 676
 677 /*-------------------------------------------------------------------------*/
 678
 679 // Would be best to create all qh's from config descriptors,
 680 // when each interface/altsetting is established.  Unlink
 681 // any previous qh and cancel its urbs first; endpoints are
 682 // implicitly reset then (data toggle too).
 683 // That'd mean updating how usbcore talks to HCDs. (2.7?)
 684
 685
 686 /*
 687  * Each QH holds a qtd list; a QH is used for everything except iso.
 688  *
 689  * For interrupt urbs, the scheduler must set the microframe scheduling
 690  * mask(s) each time the QH gets scheduled.  For highspeed, that's
 691  * just one microframe in the s-mask.  For split interrupt transactions
 692  * there are additional complications: c-mask, maybe FSTNs.
 693  */
 694 static struct ehci_qh *
 695 qh_make (
 696         struct ehci_hcd         *ehci,
 697         struct urb              *urb,
 698         gfp_t                   flags
 699 ) {
 700         struct ehci_qh          *qh = ehci_qh_alloc (ehci, flags);
 701         u32                     info1 = 0, info2 = 0;
 702         int                     is_input, type;
 703         int                     maxp = 0;
 704         struct usb_tt           *tt = urb->dev->tt;
 705
 706         if (!qh)
 707                 return qh;
 708
 709         /*
 710          * init endpoint/device data for this QH
 711          */
 712         info1 |= usb_pipeendpoint (urb->pipe) << 8;
 713         info1 |= usb_pipedevice (urb->pipe) << 0;
 714
 715         is_input = usb_pipein (urb->pipe);
 716         type = usb_pipetype (urb->pipe);
 717         maxp = usb_maxpacket (urb->dev, urb->pipe, !is_input);
 718
 719         /* 1024 byte maxpacket is a hardware ceiling.  High bandwidth
 720          * acts like up to 3KB, but is built from smaller packets.
 721          */
 722         if (max_packet(maxp) > 1024) {
 723                 ehci_dbg(ehci, "bogus qh maxpacket %d\n", max_packet(maxp));
 724                 goto done;
 725         }
 726
 727         /* Compute interrupt scheduling parameters just once, and save.
 728          * - allowing for high bandwidth, how many nsec/uframe are used?
 729          * - split transactions need a second CSPLIT uframe; same question
 730          * - splits also need a schedule gap (for full/low speed I/O)
 731          * - qh has a polling interval
 732          *
 733          * For control/bulk requests, the HC or TT handles these.
 734          */
 735         if (type == PIPE_INTERRUPT) {
 736                 qh->usecs = NS_TO_US(usb_calc_bus_time(USB_SPEED_HIGH,
 737                                 is_input, 0,
 738                                 hb_mult(maxp) * max_packet(maxp)));
 739                 qh->start = NO_FRAME;
 740
 741                 if (urb->dev->speed == USB_SPEED_HIGH) {
 742                         qh->c_usecs = 0;
 743                         qh->gap_uf = 0;
 744
 745                         qh->period = urb->interval >> 3;
 746                         if (qh->period == 0 && urb->interval != 1) {
 747                                 /* NOTE interval 2 or 4 uframes could work.
 748                                  * But interval 1 scheduling is simpler, and
 749                                  * includes high bandwidth.
 750                                  */
 751                                 dbg ("intr period %d uframes, NYET!",
 752                                                 urb->interval);
 753                                 goto done;
 754                         }
 755                 } else {
 756                         int             think_time;
 757
 758                         /* gap is f(FS/LS transfer times) */
 759                         qh->gap_uf = 1 + usb_calc_bus_time (urb->dev->speed,
 760                                         is_input, 0, maxp) / (125 * 1000);
 761
 762                         /* FIXME this just approximates SPLIT/CSPLIT times */
 763                         if (is_input) {         // SPLIT, gap, CSPLIT+DATA
 764                                 qh->c_usecs = qh->usecs + HS_USECS (0);
 765                                 qh->usecs = HS_USECS (1);
 766                         } else {                // SPLIT+DATA, gap, CSPLIT
 767                                 qh->usecs += HS_USECS (1);
 768                                 qh->c_usecs = HS_USECS (0);
 769                         }
 770
 771                         think_time = tt ? tt->think_time : 0;
 772                         qh->tt_usecs = NS_TO_US (think_time +
 773                                         usb_calc_bus_time (urb->dev->speed,
 774                                         is_input, 0, max_packet (maxp)));
 775                         qh->period = urb->interval;
 776                 }
 777         }
 778
 779         /* support for tt scheduling, and access to toggles */
 780         qh->dev = urb->dev;
 781
 782         /* using TT? */
 783         switch (urb->dev->speed) {
 784         case USB_SPEED_LOW:
 785                 info1 |= (1 << 12);     /* EPS "low" */
 786                 /* FALL THROUGH */
 787
 788         case USB_SPEED_FULL:
 789                 /* EPS 0 means "full" */
 790                 if (type != PIPE_INTERRUPT)
 791                         info1 |= (EHCI_TUNE_RL_TT << 28);
 792                 if (type == PIPE_CONTROL) {
 793                         info1 |= (1 << 27);     /* for TT */
 794                         info1 |= 1 << 14;       /* toggle from qtd */
 795                 }
 796                 info1 |= maxp << 16;
 797
 798                 info2 |= (EHCI_TUNE_MULT_TT << 30);
 799
 800                 /* Some Freescale processors have an erratum in which the
 801                  * port number in the queue head was 0..N-1 instead of 1..N.
 802                  */
 803                 if (ehci_has_fsl_portno_bug(ehci))
 804                         info2 |= (urb->dev->ttport-1) << 23;
 805                 else
 806                         info2 |= urb->dev->ttport << 23;
 807
 808                 /* set the address of the TT; for TDI's integrated
 809                  * root hub tt, leave it zeroed.
 810                  */
 811                 if (tt && tt->hub != ehci_to_hcd(ehci)->self.root_hub)
 812                         info2 |= tt->hub->devnum << 16;
 813
 814                 /* NOTE:  if (PIPE_INTERRUPT) { scheduler sets c-mask } */
 815
 816                 break;
 817
 818         case USB_SPEED_HIGH:            /* no TT involved */
 819                 info1 |= (2 << 12);     /* EPS "high" */
 820                 if (type == PIPE_CONTROL) {
 821                         info1 |= (EHCI_TUNE_RL_HS << 28);
 822                         info1 |= 64 << 16;      /* usb2 fixed maxpacket */
 823                         info1 |= 1 << 14;       /* toggle from qtd */
 824                         info2 |= (EHCI_TUNE_MULT_HS << 30);
 825                 } else if (type == PIPE_BULK) {
 826                         info1 |= (EHCI_TUNE_RL_HS << 28);
 827                         /* The USB spec says that high speed bulk endpoints
 828                          * always use 512 byte maxpacket.  But some device
 829                          * vendors decided to ignore that, and MSFT is happy
 830                          * to help them do so.  So now people expect to use
 831                          * such nonconformant devices with Linux too; sigh.
 832                          */
 833                         info1 |= max_packet(maxp) << 16;
 834                         info2 |= (EHCI_TUNE_MULT_HS << 30);
 835                 } else {                /* PIPE_INTERRUPT */
 836                         info1 |= max_packet (maxp) << 16;
 837                         info2 |= hb_mult (maxp) << 30;
 838                 }
 839                 break;
 840         default:
 841                 dbg ("bogus dev %p speed %d", urb->dev, urb->dev->speed);
 842 done:
 843                 qh_put (qh);
 844                 return NULL;
 845         }
 846
 847         /* NOTE:  if (PIPE_INTERRUPT) { scheduler sets s-mask } */
 848
 849         /* init as live, toggle clear, advance to dummy */
 850         qh->qh_state = QH_STATE_IDLE;
 851         qh->hw_info1 = cpu_to_hc32(ehci, info1);
 852         qh->hw_info2 = cpu_to_hc32(ehci, info2);
 853         usb_settoggle (urb->dev, usb_pipeendpoint (urb->pipe), !is_input, 1);
 854         qh_refresh (ehci, qh);
 855         return qh;
 856 }
 857
 858 /*-------------------------------------------------------------------------*/
 859
 860 /* move qh (and its qtds) onto async queue; maybe enable queue.  */
 861
 862 static void qh_link_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
 863 {
 864         __hc32          dma = QH_NEXT(ehci, qh->qh_dma);
 865         struct ehci_qh  *head;
 866
 867         /* (re)start the async schedule? */
 868         head = ehci->async;
 869         timer_action_done (ehci, TIMER_ASYNC_OFF);
 870         if (!head->qh_next.qh) {
 871                 u32     cmd = ehci_readl(ehci, &ehci->regs->command);
 872
 873                 if (!(cmd & CMD_ASE)) {
 874                         /* in case a clear of CMD_ASE didn't take yet */
 875                         (void)handshake(ehci, &ehci->regs->status,
 876                                         STS_ASS, 0, 150);
 877                         cmd |= CMD_ASE | CMD_RUN;
 878                         ehci_writel(ehci, cmd, &ehci->regs->command);
 879                         ehci_to_hcd(ehci)->state = HC_STATE_RUNNING;
 880                         /* posted write need not be known to HC yet ... */
 881                 }
 882         }
 883
 884         /* clear halt and/or toggle; and maybe recover from silicon quirk */
 885         if (qh->qh_state == QH_STATE_IDLE)
 886                 qh_refresh (ehci, qh);
 887
 888         /* splice right after start */
 889         qh->qh_next = head->qh_next;
 890         qh->hw_next = head->hw_next;
 891         wmb ();
 892
 893         head->qh_next.qh = qh;
 894         head->hw_next = dma;
 895
 896         qh->xacterrs = QH_XACTERR_MAX;
 897         qh->qh_state = QH_STATE_LINKED;
 898         /* qtd completions reported later by interrupt */
 899 }
 900
 901 /*-------------------------------------------------------------------------*/
 902
 903 /*
 904  * For control/bulk/interrupt, return QH with these TDs appended.
 905  * Allocates and initializes the QH if necessary.
 906  * Returns null if it can't allocate a QH it needs to.
 907  * If the QH has TDs (urbs) already, that's great.
 908  */
 909 static struct ehci_qh *qh_append_tds (
 910         struct ehci_hcd         *ehci,
 911         struct urb              *urb,
 912         struct list_head        *qtd_list,
 913         int                     epnum,
 914         void                    **ptr
 915 )
 916 {
 917         struct ehci_qh          *qh = NULL;
 918         __hc32                  qh_addr_mask = cpu_to_hc32(ehci, 0x7f);
 919
 920         qh = (struct ehci_qh *) *ptr;
 921         if (unlikely (qh == NULL)) {
 922                 /* can't sleep here, we have ehci->lock... */
 923                 qh = qh_make (ehci, urb, GFP_ATOMIC);
 924                 *ptr = qh;
 925         }
 926         if (likely (qh != NULL)) {
 927                 struct ehci_qtd *qtd;
 928
 929                 if (unlikely (list_empty (qtd_list)))
 930                         qtd = NULL;
 931                 else
 932                         qtd = list_entry (qtd_list->next, struct ehci_qtd,
 933                                         qtd_list);
 934
 935                 /* control qh may need patching ... */
 936                 if (unlikely (epnum == 0)) {
 937
 938                         /* usb_reset_device() briefly reverts to address 0 */
 939                         if (usb_pipedevice (urb->pipe) == 0)
 940                                 qh->hw_info1 &= ~qh_addr_mask;
 941                 }
 942
 943                 /* just one way to queue requests: swap with the dummy qtd.
 944                  * only hc or qh_refresh() ever modify the overlay.
 945                  */
 946                 if (likely (qtd != NULL)) {
 947                         struct ehci_qtd         *dummy;
 948                         dma_addr_t              dma;
 949                         __hc32                  token;
 950
 951                         /* to avoid racing the HC, use the dummy td instead of
 952                          * the first td of our list (becomes new dummy).  both
 953                          * tds stay deactivated until we're done, when the
 954                          * HC is allowed to fetch the old dummy (4.10.2).
 955                          */
 956                         token = qtd->hw_token;
 957                         qtd->hw_token = HALT_BIT(ehci);
 958                         wmb ();
 959                         dummy = qh->dummy;
 960
 961                         dma = dummy->qtd_dma;
 962                         *dummy = *qtd;
 963                         dummy->qtd_dma = dma;
 964
 965                         list_del (&qtd->qtd_list);
 966                         list_add (&dummy->qtd_list, qtd_list);
 967                         list_splice_tail(qtd_list, &qh->qtd_list);
 968
 969                         ehci_qtd_init(ehci, qtd, qtd->qtd_dma);
 970                         qh->dummy = qtd;
 971
 972                         /* hc must see the new dummy at list end */
 973                         dma = qtd->qtd_dma;
 974                         qtd = list_entry (qh->qtd_list.prev,
 975                                         struct ehci_qtd, qtd_list);
 976                         qtd->hw_next = QTD_NEXT(ehci, dma);
 977
 978                         /* let the hc process these next qtds */
 979                         wmb ();
 980                         dummy->hw_token = token;
 981
 982                         urb->hcpriv = qh_get (qh);
 983                 }
 984         }
 985         return qh;
 986 }
 987
 988 /*-------------------------------------------------------------------------*/
 989
 990 static int
 991 submit_async (
 992         struct ehci_hcd         *ehci,
 993         struct urb              *urb,
 994         struct list_head        *qtd_list,
 995         gfp_t                   mem_flags
 996 ) {
 997         struct ehci_qtd         *qtd;
 998         int                     epnum;
 999         unsigned long           flags;
1000         struct ehci_qh          *qh = NULL;
1001         int                     rc;
1002
1003         qtd = list_entry (qtd_list->next, struct ehci_qtd, qtd_list);
1004         epnum = urb->ep->desc.bEndpointAddress;
1005
1006 #ifdef EHCI_URB_TRACE
1007         ehci_dbg (ehci,
1008                 "%s %s urb %p ep%d%s len %d, qtd %p [qh %p]\n",
1009                 __func__, urb->dev->devpath, urb,
1010                 epnum & 0x0f, (epnum & USB_DIR_IN) ? "in" : "out",
1011                 urb->transfer_buffer_length,
1012                 qtd, urb->ep->hcpriv);
1013 #endif
1014
1015         spin_lock_irqsave (&ehci->lock, flags);
1016         if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE,
1017                                &ehci_to_hcd(ehci)->flags))) {
1018                 rc = -ESHUTDOWN;
1019                 goto done;
1020         }
1021         rc = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
1022         if (unlikely(rc))
1023                 goto done;
1024
1025         qh = qh_append_tds(ehci, urb, qtd_list, epnum, &urb->ep->hcpriv);
1026         if (unlikely(qh == NULL)) {
1027                 usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
1028                 rc = -ENOMEM;
1029                 goto done;
1030         }
1031
1032         /* Control/bulk operations through TTs don't need scheduling,
1033          * the HC and TT handle it when the TT has a buffer ready.
1034          */
1035         if (likely (qh->qh_state == QH_STATE_IDLE))
1036                 qh_link_async (ehci, qh_get (qh));
1037  done:
1038         spin_unlock_irqrestore (&ehci->lock, flags);
1039         if (unlikely (qh == NULL))
1040                 qtd_list_free (ehci, urb, qtd_list);
1041         return rc;
1042 }
1043
1044 /*-------------------------------------------------------------------------*/
1045
1046 /* the async qh for the qtds being reclaimed are now unlinked from the HC */
1047
1048 static void end_unlink_async (struct ehci_hcd *ehci)
1049 {
1050         struct ehci_qh          *qh = ehci->reclaim;
1051         struct ehci_qh          *next;
1052
1053         iaa_watchdog_done(ehci);
1054
1055         // qh->hw_next = cpu_to_hc32(qh->qh_dma);
1056         qh->qh_state = QH_STATE_IDLE;
1057         qh->qh_next.qh = NULL;
1058         qh_put (qh);                    // refcount from reclaim
1059
1060         /* other unlink(s) may be pending (in QH_STATE_UNLINK_WAIT) */
1061         next = qh->reclaim;
1062         ehci->reclaim = next;
1063         qh->reclaim = NULL;
1064
1065         qh_completions (ehci, qh);
1066
1067         if (!list_empty (&qh->qtd_list)
1068                         && HC_IS_RUNNING (ehci_to_hcd(ehci)->state))
1069                 qh_link_async (ehci, qh);
1070         else {
1071                 qh_put (qh);            // refcount from async list
1072
1073                 /* it's not free to turn the async schedule on/off; leave it
1074                  * active but idle for a while once it empties.
1075                  */
1076                 if (HC_IS_RUNNING (ehci_to_hcd(ehci)->state)
1077                                 && ehci->async->qh_next.qh == NULL)
1078                         timer_action (ehci, TIMER_ASYNC_OFF);
1079         }
1080
1081         if (next) {
1082                 ehci->reclaim = NULL;
1083                 start_unlink_async (ehci, next);
1084         }
1085 }
1086
1087 /* makes sure the async qh will become idle */
1088 /* caller must own ehci->lock */
1089
1090 static void start_unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
1091 {
1092         int             cmd = ehci_readl(ehci, &ehci->regs->command);
1093         struct ehci_qh  *prev;
1094
1095 #ifdef DEBUG
1096         assert_spin_locked(&ehci->lock);
1097         if (ehci->reclaim
1098                         || (qh->qh_state != QH_STATE_LINKED
1099                                 && qh->qh_state != QH_STATE_UNLINK_WAIT)
1100                         )
1101                 BUG ();
1102 #endif
1103
1104         /* stop async schedule right now? */
1105         if (unlikely (qh == ehci->async)) {
1106                 /* can't get here without STS_ASS set */
1107                 if (ehci_to_hcd(ehci)->state != HC_STATE_HALT
1108                                 && !ehci->reclaim) {
1109                         /* ... and CMD_IAAD clear */
1110                         ehci_writel(ehci, cmd & ~CMD_ASE,
1111                                     &ehci->regs->command);
1112                         wmb ();
1113                         // handshake later, if we need to
1114                         timer_action_done (ehci, TIMER_ASYNC_OFF);
1115                 }
1116                 return;
1117         }
1118
1119         qh->qh_state = QH_STATE_UNLINK;
1120         ehci->reclaim = qh = qh_get (qh);
1121
1122         prev = ehci->async;
1123         while (prev->qh_next.qh != qh)
1124                 prev = prev->qh_next.qh;
1125
1126         prev->hw_next = qh->hw_next;
1127         prev->qh_next = qh->qh_next;
1128         wmb ();
1129
1130         /* If the controller isn't running, we don't have to wait for it */
1131         if (unlikely(!HC_IS_RUNNING(ehci_to_hcd(ehci)->state))) {
1132                 /* if (unlikely (qh->reclaim != 0))
1133                  *      this will recurse, probably not much
1134                  */
1135                 end_unlink_async (ehci);
1136                 return;
1137         }
1138
1139         cmd |= CMD_IAAD;
1140         ehci_writel(ehci, cmd, &ehci->regs->command);
1141         (void)ehci_readl(ehci, &ehci->regs->command);
1142         iaa_watchdog_start(ehci);
1143 }
1144
1145 /*-------------------------------------------------------------------------*/
1146
1147 static void scan_async (struct ehci_hcd *ehci)
1148 {
1149         struct ehci_qh          *qh;
1150         enum ehci_timer_action  action = TIMER_IO_WATCHDOG;
1151
1152         ehci->stamp = ehci_readl(ehci, &ehci->regs->frame_index);
1153         timer_action_done (ehci, TIMER_ASYNC_SHRINK);
1154 rescan:
1155         qh = ehci->async->qh_next.qh;
1156         if (likely (qh != NULL)) {
1157                 do {
1158                         /* clean any finished work for this qh */
1159                         if (!list_empty (&qh->qtd_list)
1160                                         && qh->stamp != ehci->stamp) {
1161                                 int temp;
1162
1163                                 /* unlinks could happen here; completion
1164                                  * reporting drops the lock.  rescan using
1165                                  * the latest schedule, but don't rescan
1166                                  * qhs we already finished (no looping).
1167                                  */
1168                                 qh = qh_get (qh);
1169                                 qh->stamp = ehci->stamp;
1170                                 temp = qh_completions (ehci, qh);
1171                                 qh_put (qh);
1172                                 if (temp != 0) {
1173                                         goto rescan;
1174                                 }
1175                         }
1176
1177                         /* unlink idle entries, reducing DMA usage as well
1178                          * as HCD schedule-scanning costs.  delay for any qh
1179                          * we just scanned, there's a not-unusual case that it
1180                          * doesn't stay idle for long.
1181                          * (plus, avoids some kind of re-activation race.)
1182                          */
1183                         if (list_empty(&qh->qtd_list)
1184                                         && qh->qh_state == QH_STATE_LINKED) {
1185                                 if (!ehci->reclaim
1186                                         && ((ehci->stamp - qh->stamp) & 0x1fff)
1187                                                 >= (EHCI_SHRINK_FRAMES * 8))
1188                                         start_unlink_async(ehci, qh);
1189                                 else
1190                                         action = TIMER_ASYNC_SHRINK;
1191                         }
1192
1193                         qh = qh->qh_next.qh;
1194                 } while (qh);
1195         }
1196         if (action == TIMER_ASYNC_SHRINK)
1197                 timer_action (ehci, TIMER_ASYNC_SHRINK);
1198 }