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