Merge branch 'fb' into devel
[linux-2.6] / 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_tt_clear_buffer (urb->dev, urb->pipe);
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                 if ((token & QTD_STS_ACTIVE) == 0) {
337
338                         /* on STALL, error, and short reads this urb must
339                          * complete and all its qtds must be recycled.
340                          */
341                         if ((token & QTD_STS_HALT) != 0) {
342                                 stopped = 1;
343
344                         /* magic dummy for some short reads; qh won't advance.
345                          * that silicon quirk can kick in with this dummy too.
346                          *
347                          * other short reads won't stop the queue, including
348                          * control transfers (status stage handles that) or
349                          * most other single-qtd reads ... the queue stops if
350                          * URB_SHORT_NOT_OK was set so the driver submitting
351                          * the urbs could clean it up.
352                          */
353                         } else if (IS_SHORT_READ (token)
354                                         && !(qtd->hw_alt_next
355                                                 & EHCI_LIST_END(ehci))) {
356                                 stopped = 1;
357                                 goto halt;
358                         }
359
360                 /* stop scanning when we reach qtds the hc is using */
361                 } else if (likely (!stopped
362                                 && HC_IS_RUNNING (ehci_to_hcd(ehci)->state))) {
363                         break;
364
365                 /* scan the whole queue for unlinks whenever it stops */
366                 } else {
367                         stopped = 1;
368
369                         /* cancel everything if we halt, suspend, etc */
370                         if (!HC_IS_RUNNING(ehci_to_hcd(ehci)->state))
371                                 last_status = -ESHUTDOWN;
372
373                         /* this qtd is active; skip it unless a previous qtd
374                          * for its urb faulted, or its urb was canceled.
375                          */
376                         else if (last_status == -EINPROGRESS && !urb->unlinked)
377                                 continue;
378
379                         /* qh unlinked; token in overlay may be most current */
380                         if (state == QH_STATE_IDLE
381                                         && cpu_to_hc32(ehci, qtd->qtd_dma)
382                                                 == qh->hw_current)
383                                 token = hc32_to_cpu(ehci, qh->hw_token);
384
385                         /* force halt for unlinked or blocked qh, so we'll
386                          * patch the qh later and so that completions can't
387                          * activate it while we "know" it's stopped.
388                          */
389                         if ((halt & qh->hw_token) == 0) {
390 halt:
391                                 qh->hw_token |= halt;
392                                 wmb ();
393                         }
394                 }
395
396                 /* unless we already know the urb's status, collect qtd status
397                  * and update count of bytes transferred.  in common short read
398                  * cases with only one data qtd (including control transfers),
399                  * queue processing won't halt.  but with two or more qtds (for
400                  * example, with a 32 KB transfer), when the first qtd gets a
401                  * short read the second must be removed by hand.
402                  */
403                 if (last_status == -EINPROGRESS) {
404                         last_status = qtd_copy_status(ehci, urb,
405                                         qtd->length, token);
406                         if (last_status == -EREMOTEIO
407                                         && (qtd->hw_alt_next
408                                                 & EHCI_LIST_END(ehci)))
409                                 last_status = -EINPROGRESS;
410                 }
411
412                 /* if we're removing something not at the queue head,
413                  * patch the hardware queue pointer.
414                  */
415                 if (stopped && qtd->qtd_list.prev != &qh->qtd_list) {
416                         last = list_entry (qtd->qtd_list.prev,
417                                         struct ehci_qtd, qtd_list);
418                         last->hw_next = qtd->hw_next;
419                 }
420
421                 /* remove qtd; it's recycled after possible urb completion */
422                 list_del (&qtd->qtd_list);
423                 last = qtd;
424         }
425
426         /* last urb's completion might still need calling */
427         if (likely (last != NULL)) {
428                 ehci_urb_done(ehci, last->urb, last_status);
429                 count++;
430                 ehci_qtd_free (ehci, last);
431         }
432
433         /* restore original state; caller must unlink or relink */
434         qh->qh_state = state;
435
436         /* be sure the hardware's done with the qh before refreshing
437          * it after fault cleanup, or recovering from silicon wrongly
438          * overlaying the dummy qtd (which reduces DMA chatter).
439          */
440         if (stopped != 0 || qh->hw_qtd_next == EHCI_LIST_END(ehci)) {
441                 switch (state) {
442                 case QH_STATE_IDLE:
443                         qh_refresh(ehci, qh);
444                         break;
445                 case QH_STATE_LINKED:
446                         /* We won't refresh a QH that's linked (after the HC
447                          * stopped the queue).  That avoids a race:
448                          *  - HC reads first part of QH;
449                          *  - CPU updates that first part and the token;
450                          *  - HC reads rest of that QH, including token
451                          * Result:  HC gets an inconsistent image, and then
452                          * DMAs to/from the wrong memory (corrupting it).
453                          *
454                          * That should be rare for interrupt transfers,
455                          * except maybe high bandwidth ...
456                          */
457                         if ((cpu_to_hc32(ehci, QH_SMASK)
458                                         & qh->hw_info2) != 0) {
459                                 intr_deschedule (ehci, qh);
460                                 (void) qh_schedule (ehci, qh);
461                         } else
462                                 unlink_async (ehci, qh);
463                         break;
464                 /* otherwise, unlink already started */
465                 }
466         }
467
468         return count;
469 }
470
471 /*-------------------------------------------------------------------------*/
472
473 // high bandwidth multiplier, as encoded in highspeed endpoint descriptors
474 #define hb_mult(wMaxPacketSize) (1 + (((wMaxPacketSize) >> 11) & 0x03))
475 // ... and packet size, for any kind of endpoint descriptor
476 #define max_packet(wMaxPacketSize) ((wMaxPacketSize) & 0x07ff)
477
478 /*
479  * reverse of qh_urb_transaction:  free a list of TDs.
480  * used for cleanup after errors, before HC sees an URB's TDs.
481  */
482 static void qtd_list_free (
483         struct ehci_hcd         *ehci,
484         struct urb              *urb,
485         struct list_head        *qtd_list
486 ) {
487         struct list_head        *entry, *temp;
488
489         list_for_each_safe (entry, temp, qtd_list) {
490                 struct ehci_qtd *qtd;
491
492                 qtd = list_entry (entry, struct ehci_qtd, qtd_list);
493                 list_del (&qtd->qtd_list);
494                 ehci_qtd_free (ehci, qtd);
495         }
496 }
497
498 /*
499  * create a list of filled qtds for this URB; won't link into qh.
500  */
501 static struct list_head *
502 qh_urb_transaction (
503         struct ehci_hcd         *ehci,
504         struct urb              *urb,
505         struct list_head        *head,
506         gfp_t                   flags
507 ) {
508         struct ehci_qtd         *qtd, *qtd_prev;
509         dma_addr_t              buf;
510         int                     len, maxpacket;
511         int                     is_input;
512         u32                     token;
513
514         /*
515          * URBs map to sequences of QTDs:  one logical transaction
516          */
517         qtd = ehci_qtd_alloc (ehci, flags);
518         if (unlikely (!qtd))
519                 return NULL;
520         list_add_tail (&qtd->qtd_list, head);
521         qtd->urb = urb;
522
523         token = QTD_STS_ACTIVE;
524         token |= (EHCI_TUNE_CERR << 10);
525         /* for split transactions, SplitXState initialized to zero */
526
527         len = urb->transfer_buffer_length;
528         is_input = usb_pipein (urb->pipe);
529         if (usb_pipecontrol (urb->pipe)) {
530                 /* SETUP pid */
531                 qtd_fill(ehci, qtd, urb->setup_dma,
532                                 sizeof (struct usb_ctrlrequest),
533                                 token | (2 /* "setup" */ << 8), 8);
534
535                 /* ... and always at least one more pid */
536                 token ^= QTD_TOGGLE;
537                 qtd_prev = qtd;
538                 qtd = ehci_qtd_alloc (ehci, flags);
539                 if (unlikely (!qtd))
540                         goto cleanup;
541                 qtd->urb = urb;
542                 qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
543                 list_add_tail (&qtd->qtd_list, head);
544
545                 /* for zero length DATA stages, STATUS is always IN */
546                 if (len == 0)
547                         token |= (1 /* "in" */ << 8);
548         }
549
550         /*
551          * data transfer stage:  buffer setup
552          */
553         buf = urb->transfer_dma;
554
555         if (is_input)
556                 token |= (1 /* "in" */ << 8);
557         /* else it's already initted to "out" pid (0 << 8) */
558
559         maxpacket = max_packet(usb_maxpacket(urb->dev, urb->pipe, !is_input));
560
561         /*
562          * buffer gets wrapped in one or more qtds;
563          * last one may be "short" (including zero len)
564          * and may serve as a control status ack
565          */
566         for (;;) {
567                 int this_qtd_len;
568
569                 this_qtd_len = qtd_fill(ehci, qtd, buf, len, token, maxpacket);
570                 len -= this_qtd_len;
571                 buf += this_qtd_len;
572
573                 /*
574                  * short reads advance to a "magic" dummy instead of the next
575                  * qtd ... that forces the queue to stop, for manual cleanup.
576                  * (this will usually be overridden later.)
577                  */
578                 if (is_input)
579                         qtd->hw_alt_next = ehci->async->hw_alt_next;
580
581                 /* qh makes control packets use qtd toggle; maybe switch it */
582                 if ((maxpacket & (this_qtd_len + (maxpacket - 1))) == 0)
583                         token ^= QTD_TOGGLE;
584
585                 if (likely (len <= 0))
586                         break;
587
588                 qtd_prev = qtd;
589                 qtd = ehci_qtd_alloc (ehci, flags);
590                 if (unlikely (!qtd))
591                         goto cleanup;
592                 qtd->urb = urb;
593                 qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
594                 list_add_tail (&qtd->qtd_list, head);
595         }
596
597         /*
598          * unless the caller requires manual cleanup after short reads,
599          * have the alt_next mechanism keep the queue running after the
600          * last data qtd (the only one, for control and most other cases).
601          */
602         if (likely ((urb->transfer_flags & URB_SHORT_NOT_OK) == 0
603                                 || usb_pipecontrol (urb->pipe)))
604                 qtd->hw_alt_next = EHCI_LIST_END(ehci);
605
606         /*
607          * control requests may need a terminating data "status" ack;
608          * bulk ones may need a terminating short packet (zero length).
609          */
610         if (likely (urb->transfer_buffer_length != 0)) {
611                 int     one_more = 0;
612
613                 if (usb_pipecontrol (urb->pipe)) {
614                         one_more = 1;
615                         token ^= 0x0100;        /* "in" <--> "out"  */
616                         token |= QTD_TOGGLE;    /* force DATA1 */
617                 } else if (usb_pipebulk (urb->pipe)
618                                 && (urb->transfer_flags & URB_ZERO_PACKET)
619                                 && !(urb->transfer_buffer_length % maxpacket)) {
620                         one_more = 1;
621                 }
622                 if (one_more) {
623                         qtd_prev = qtd;
624                         qtd = ehci_qtd_alloc (ehci, flags);
625                         if (unlikely (!qtd))
626                                 goto cleanup;
627                         qtd->urb = urb;
628                         qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
629                         list_add_tail (&qtd->qtd_list, head);
630
631                         /* never any data in such packets */
632                         qtd_fill(ehci, qtd, 0, 0, token, 0);
633                 }
634         }
635
636         /* by default, enable interrupt on urb completion */
637         if (likely (!(urb->transfer_flags & URB_NO_INTERRUPT)))
638                 qtd->hw_token |= cpu_to_hc32(ehci, QTD_IOC);
639         return head;
640
641 cleanup:
642         qtd_list_free (ehci, urb, head);
643         return NULL;
644 }
645
646 /*-------------------------------------------------------------------------*/
647
648 // Would be best to create all qh's from config descriptors,
649 // when each interface/altsetting is established.  Unlink
650 // any previous qh and cancel its urbs first; endpoints are
651 // implicitly reset then (data toggle too).
652 // That'd mean updating how usbcore talks to HCDs. (2.7?)
653
654
655 /*
656  * Each QH holds a qtd list; a QH is used for everything except iso.
657  *
658  * For interrupt urbs, the scheduler must set the microframe scheduling
659  * mask(s) each time the QH gets scheduled.  For highspeed, that's
660  * just one microframe in the s-mask.  For split interrupt transactions
661  * there are additional complications: c-mask, maybe FSTNs.
662  */
663 static struct ehci_qh *
664 qh_make (
665         struct ehci_hcd         *ehci,
666         struct urb              *urb,
667         gfp_t                   flags
668 ) {
669         struct ehci_qh          *qh = ehci_qh_alloc (ehci, flags);
670         u32                     info1 = 0, info2 = 0;
671         int                     is_input, type;
672         int                     maxp = 0;
673         struct usb_tt           *tt = urb->dev->tt;
674
675         if (!qh)
676                 return qh;
677
678         /*
679          * init endpoint/device data for this QH
680          */
681         info1 |= usb_pipeendpoint (urb->pipe) << 8;
682         info1 |= usb_pipedevice (urb->pipe) << 0;
683
684         is_input = usb_pipein (urb->pipe);
685         type = usb_pipetype (urb->pipe);
686         maxp = usb_maxpacket (urb->dev, urb->pipe, !is_input);
687
688         /* 1024 byte maxpacket is a hardware ceiling.  High bandwidth
689          * acts like up to 3KB, but is built from smaller packets.
690          */
691         if (max_packet(maxp) > 1024) {
692                 ehci_dbg(ehci, "bogus qh maxpacket %d\n", max_packet(maxp));
693                 goto done;
694         }
695
696         /* Compute interrupt scheduling parameters just once, and save.
697          * - allowing for high bandwidth, how many nsec/uframe are used?
698          * - split transactions need a second CSPLIT uframe; same question
699          * - splits also need a schedule gap (for full/low speed I/O)
700          * - qh has a polling interval
701          *
702          * For control/bulk requests, the HC or TT handles these.
703          */
704         if (type == PIPE_INTERRUPT) {
705                 qh->usecs = NS_TO_US(usb_calc_bus_time(USB_SPEED_HIGH,
706                                 is_input, 0,
707                                 hb_mult(maxp) * max_packet(maxp)));
708                 qh->start = NO_FRAME;
709
710                 if (urb->dev->speed == USB_SPEED_HIGH) {
711                         qh->c_usecs = 0;
712                         qh->gap_uf = 0;
713
714                         qh->period = urb->interval >> 3;
715                         if (qh->period == 0 && urb->interval != 1) {
716                                 /* NOTE interval 2 or 4 uframes could work.
717                                  * But interval 1 scheduling is simpler, and
718                                  * includes high bandwidth.
719                                  */
720                                 dbg ("intr period %d uframes, NYET!",
721                                                 urb->interval);
722                                 goto done;
723                         }
724                 } else {
725                         int             think_time;
726
727                         /* gap is f(FS/LS transfer times) */
728                         qh->gap_uf = 1 + usb_calc_bus_time (urb->dev->speed,
729                                         is_input, 0, maxp) / (125 * 1000);
730
731                         /* FIXME this just approximates SPLIT/CSPLIT times */
732                         if (is_input) {         // SPLIT, gap, CSPLIT+DATA
733                                 qh->c_usecs = qh->usecs + HS_USECS (0);
734                                 qh->usecs = HS_USECS (1);
735                         } else {                // SPLIT+DATA, gap, CSPLIT
736                                 qh->usecs += HS_USECS (1);
737                                 qh->c_usecs = HS_USECS (0);
738                         }
739
740                         think_time = tt ? tt->think_time : 0;
741                         qh->tt_usecs = NS_TO_US (think_time +
742                                         usb_calc_bus_time (urb->dev->speed,
743                                         is_input, 0, max_packet (maxp)));
744                         qh->period = urb->interval;
745                 }
746         }
747
748         /* support for tt scheduling, and access to toggles */
749         qh->dev = urb->dev;
750
751         /* using TT? */
752         switch (urb->dev->speed) {
753         case USB_SPEED_LOW:
754                 info1 |= (1 << 12);     /* EPS "low" */
755                 /* FALL THROUGH */
756
757         case USB_SPEED_FULL:
758                 /* EPS 0 means "full" */
759                 if (type != PIPE_INTERRUPT)
760                         info1 |= (EHCI_TUNE_RL_TT << 28);
761                 if (type == PIPE_CONTROL) {
762                         info1 |= (1 << 27);     /* for TT */
763                         info1 |= 1 << 14;       /* toggle from qtd */
764                 }
765                 info1 |= maxp << 16;
766
767                 info2 |= (EHCI_TUNE_MULT_TT << 30);
768
769                 /* Some Freescale processors have an erratum in which the
770                  * port number in the queue head was 0..N-1 instead of 1..N.
771                  */
772                 if (ehci_has_fsl_portno_bug(ehci))
773                         info2 |= (urb->dev->ttport-1) << 23;
774                 else
775                         info2 |= urb->dev->ttport << 23;
776
777                 /* set the address of the TT; for TDI's integrated
778                  * root hub tt, leave it zeroed.
779                  */
780                 if (tt && tt->hub != ehci_to_hcd(ehci)->self.root_hub)
781                         info2 |= tt->hub->devnum << 16;
782
783                 /* NOTE:  if (PIPE_INTERRUPT) { scheduler sets c-mask } */
784
785                 break;
786
787         case USB_SPEED_HIGH:            /* no TT involved */
788                 info1 |= (2 << 12);     /* EPS "high" */
789                 if (type == PIPE_CONTROL) {
790                         info1 |= (EHCI_TUNE_RL_HS << 28);
791                         info1 |= 64 << 16;      /* usb2 fixed maxpacket */
792                         info1 |= 1 << 14;       /* toggle from qtd */
793                         info2 |= (EHCI_TUNE_MULT_HS << 30);
794                 } else if (type == PIPE_BULK) {
795                         info1 |= (EHCI_TUNE_RL_HS << 28);
796                         /* The USB spec says that high speed bulk endpoints
797                          * always use 512 byte maxpacket.  But some device
798                          * vendors decided to ignore that, and MSFT is happy
799                          * to help them do so.  So now people expect to use
800                          * such nonconformant devices with Linux too; sigh.
801                          */
802                         info1 |= max_packet(maxp) << 16;
803                         info2 |= (EHCI_TUNE_MULT_HS << 30);
804                 } else {                /* PIPE_INTERRUPT */
805                         info1 |= max_packet (maxp) << 16;
806                         info2 |= hb_mult (maxp) << 30;
807                 }
808                 break;
809         default:
810                 dbg ("bogus dev %p speed %d", urb->dev, urb->dev->speed);
811 done:
812                 qh_put (qh);
813                 return NULL;
814         }
815
816         /* NOTE:  if (PIPE_INTERRUPT) { scheduler sets s-mask } */
817
818         /* init as live, toggle clear, advance to dummy */
819         qh->qh_state = QH_STATE_IDLE;
820         qh->hw_info1 = cpu_to_hc32(ehci, info1);
821         qh->hw_info2 = cpu_to_hc32(ehci, info2);
822         usb_settoggle (urb->dev, usb_pipeendpoint (urb->pipe), !is_input, 1);
823         qh_refresh (ehci, qh);
824         return qh;
825 }
826
827 /*-------------------------------------------------------------------------*/
828
829 /* move qh (and its qtds) onto async queue; maybe enable queue.  */
830
831 static void qh_link_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
832 {
833         __hc32          dma = QH_NEXT(ehci, qh->qh_dma);
834         struct ehci_qh  *head;
835
836         /* (re)start the async schedule? */
837         head = ehci->async;
838         timer_action_done (ehci, TIMER_ASYNC_OFF);
839         if (!head->qh_next.qh) {
840                 u32     cmd = ehci_readl(ehci, &ehci->regs->command);
841
842                 if (!(cmd & CMD_ASE)) {
843                         /* in case a clear of CMD_ASE didn't take yet */
844                         (void)handshake(ehci, &ehci->regs->status,
845                                         STS_ASS, 0, 150);
846                         cmd |= CMD_ASE | CMD_RUN;
847                         ehci_writel(ehci, cmd, &ehci->regs->command);
848                         ehci_to_hcd(ehci)->state = HC_STATE_RUNNING;
849                         /* posted write need not be known to HC yet ... */
850                 }
851         }
852
853         /* clear halt and/or toggle; and maybe recover from silicon quirk */
854         if (qh->qh_state == QH_STATE_IDLE)
855                 qh_refresh (ehci, qh);
856
857         /* splice right after start */
858         qh->qh_next = head->qh_next;
859         qh->hw_next = head->hw_next;
860         wmb ();
861
862         head->qh_next.qh = qh;
863         head->hw_next = dma;
864
865         qh->qh_state = QH_STATE_LINKED;
866         /* qtd completions reported later by interrupt */
867 }
868
869 /*-------------------------------------------------------------------------*/
870
871 /*
872  * For control/bulk/interrupt, return QH with these TDs appended.
873  * Allocates and initializes the QH if necessary.
874  * Returns null if it can't allocate a QH it needs to.
875  * If the QH has TDs (urbs) already, that's great.
876  */
877 static struct ehci_qh *qh_append_tds (
878         struct ehci_hcd         *ehci,
879         struct urb              *urb,
880         struct list_head        *qtd_list,
881         int                     epnum,
882         void                    **ptr
883 )
884 {
885         struct ehci_qh          *qh = NULL;
886         __hc32                  qh_addr_mask = cpu_to_hc32(ehci, 0x7f);
887
888         qh = (struct ehci_qh *) *ptr;
889         if (unlikely (qh == NULL)) {
890                 /* can't sleep here, we have ehci->lock... */
891                 qh = qh_make (ehci, urb, GFP_ATOMIC);
892                 *ptr = qh;
893         }
894         if (likely (qh != NULL)) {
895                 struct ehci_qtd *qtd;
896
897                 if (unlikely (list_empty (qtd_list)))
898                         qtd = NULL;
899                 else
900                         qtd = list_entry (qtd_list->next, struct ehci_qtd,
901                                         qtd_list);
902
903                 /* control qh may need patching ... */
904                 if (unlikely (epnum == 0)) {
905
906                         /* usb_reset_device() briefly reverts to address 0 */
907                         if (usb_pipedevice (urb->pipe) == 0)
908                                 qh->hw_info1 &= ~qh_addr_mask;
909                 }
910
911                 /* just one way to queue requests: swap with the dummy qtd.
912                  * only hc or qh_refresh() ever modify the overlay.
913                  */
914                 if (likely (qtd != NULL)) {
915                         struct ehci_qtd         *dummy;
916                         dma_addr_t              dma;
917                         __hc32                  token;
918
919                         /* to avoid racing the HC, use the dummy td instead of
920                          * the first td of our list (becomes new dummy).  both
921                          * tds stay deactivated until we're done, when the
922                          * HC is allowed to fetch the old dummy (4.10.2).
923                          */
924                         token = qtd->hw_token;
925                         qtd->hw_token = HALT_BIT(ehci);
926                         wmb ();
927                         dummy = qh->dummy;
928
929                         dma = dummy->qtd_dma;
930                         *dummy = *qtd;
931                         dummy->qtd_dma = dma;
932
933                         list_del (&qtd->qtd_list);
934                         list_add (&dummy->qtd_list, qtd_list);
935                         __list_splice (qtd_list, qh->qtd_list.prev);
936
937                         ehci_qtd_init(ehci, qtd, qtd->qtd_dma);
938                         qh->dummy = qtd;
939
940                         /* hc must see the new dummy at list end */
941                         dma = qtd->qtd_dma;
942                         qtd = list_entry (qh->qtd_list.prev,
943                                         struct ehci_qtd, qtd_list);
944                         qtd->hw_next = QTD_NEXT(ehci, dma);
945
946                         /* let the hc process these next qtds */
947                         wmb ();
948                         dummy->hw_token = token;
949
950                         urb->hcpriv = qh_get (qh);
951                 }
952         }
953         return qh;
954 }
955
956 /*-------------------------------------------------------------------------*/
957
958 static int
959 submit_async (
960         struct ehci_hcd         *ehci,
961         struct urb              *urb,
962         struct list_head        *qtd_list,
963         gfp_t                   mem_flags
964 ) {
965         struct ehci_qtd         *qtd;
966         int                     epnum;
967         unsigned long           flags;
968         struct ehci_qh          *qh = NULL;
969         int                     rc;
970
971         qtd = list_entry (qtd_list->next, struct ehci_qtd, qtd_list);
972         epnum = urb->ep->desc.bEndpointAddress;
973
974 #ifdef EHCI_URB_TRACE
975         ehci_dbg (ehci,
976                 "%s %s urb %p ep%d%s len %d, qtd %p [qh %p]\n",
977                 __func__, urb->dev->devpath, urb,
978                 epnum & 0x0f, (epnum & USB_DIR_IN) ? "in" : "out",
979                 urb->transfer_buffer_length,
980                 qtd, urb->ep->hcpriv);
981 #endif
982
983         spin_lock_irqsave (&ehci->lock, flags);
984         if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE,
985                                &ehci_to_hcd(ehci)->flags))) {
986                 rc = -ESHUTDOWN;
987                 goto done;
988         }
989         rc = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
990         if (unlikely(rc))
991                 goto done;
992
993         qh = qh_append_tds(ehci, urb, qtd_list, epnum, &urb->ep->hcpriv);
994         if (unlikely(qh == NULL)) {
995                 usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
996                 rc = -ENOMEM;
997                 goto done;
998         }
999
1000         /* Control/bulk operations through TTs don't need scheduling,
1001          * the HC and TT handle it when the TT has a buffer ready.
1002          */
1003         if (likely (qh->qh_state == QH_STATE_IDLE))
1004                 qh_link_async (ehci, qh_get (qh));
1005  done:
1006         spin_unlock_irqrestore (&ehci->lock, flags);
1007         if (unlikely (qh == NULL))
1008                 qtd_list_free (ehci, urb, qtd_list);
1009         return rc;
1010 }
1011
1012 /*-------------------------------------------------------------------------*/
1013
1014 /* the async qh for the qtds being reclaimed are now unlinked from the HC */
1015
1016 static void end_unlink_async (struct ehci_hcd *ehci)
1017 {
1018         struct ehci_qh          *qh = ehci->reclaim;
1019         struct ehci_qh          *next;
1020
1021         iaa_watchdog_done(ehci);
1022
1023         // qh->hw_next = cpu_to_hc32(qh->qh_dma);
1024         qh->qh_state = QH_STATE_IDLE;
1025         qh->qh_next.qh = NULL;
1026         qh_put (qh);                    // refcount from reclaim
1027
1028         /* other unlink(s) may be pending (in QH_STATE_UNLINK_WAIT) */
1029         next = qh->reclaim;
1030         ehci->reclaim = next;
1031         qh->reclaim = NULL;
1032
1033         qh_completions (ehci, qh);
1034
1035         if (!list_empty (&qh->qtd_list)
1036                         && HC_IS_RUNNING (ehci_to_hcd(ehci)->state))
1037                 qh_link_async (ehci, qh);
1038         else {
1039                 qh_put (qh);            // refcount from async list
1040
1041                 /* it's not free to turn the async schedule on/off; leave it
1042                  * active but idle for a while once it empties.
1043                  */
1044                 if (HC_IS_RUNNING (ehci_to_hcd(ehci)->state)
1045                                 && ehci->async->qh_next.qh == NULL)
1046                         timer_action (ehci, TIMER_ASYNC_OFF);
1047         }
1048
1049         if (next) {
1050                 ehci->reclaim = NULL;
1051                 start_unlink_async (ehci, next);
1052         }
1053 }
1054
1055 /* makes sure the async qh will become idle */
1056 /* caller must own ehci->lock */
1057
1058 static void start_unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
1059 {
1060         int             cmd = ehci_readl(ehci, &ehci->regs->command);
1061         struct ehci_qh  *prev;
1062
1063 #ifdef DEBUG
1064         assert_spin_locked(&ehci->lock);
1065         if (ehci->reclaim
1066                         || (qh->qh_state != QH_STATE_LINKED
1067                                 && qh->qh_state != QH_STATE_UNLINK_WAIT)
1068                         )
1069                 BUG ();
1070 #endif
1071
1072         /* stop async schedule right now? */
1073         if (unlikely (qh == ehci->async)) {
1074                 /* can't get here without STS_ASS set */
1075                 if (ehci_to_hcd(ehci)->state != HC_STATE_HALT
1076                                 && !ehci->reclaim) {
1077                         /* ... and CMD_IAAD clear */
1078                         ehci_writel(ehci, cmd & ~CMD_ASE,
1079                                     &ehci->regs->command);
1080                         wmb ();
1081                         // handshake later, if we need to
1082                         timer_action_done (ehci, TIMER_ASYNC_OFF);
1083                 }
1084                 return;
1085         }
1086
1087         qh->qh_state = QH_STATE_UNLINK;
1088         ehci->reclaim = qh = qh_get (qh);
1089
1090         prev = ehci->async;
1091         while (prev->qh_next.qh != qh)
1092                 prev = prev->qh_next.qh;
1093
1094         prev->hw_next = qh->hw_next;
1095         prev->qh_next = qh->qh_next;
1096         wmb ();
1097
1098         if (unlikely (ehci_to_hcd(ehci)->state == HC_STATE_HALT)) {
1099                 /* if (unlikely (qh->reclaim != 0))
1100                  *      this will recurse, probably not much
1101                  */
1102                 end_unlink_async (ehci);
1103                 return;
1104         }
1105
1106         cmd |= CMD_IAAD;
1107         ehci_writel(ehci, cmd, &ehci->regs->command);
1108         (void)ehci_readl(ehci, &ehci->regs->command);
1109         iaa_watchdog_start(ehci);
1110 }
1111
1112 /*-------------------------------------------------------------------------*/
1113
1114 static void scan_async (struct ehci_hcd *ehci)
1115 {
1116         struct ehci_qh          *qh;
1117         enum ehci_timer_action  action = TIMER_IO_WATCHDOG;
1118
1119         if (!++(ehci->stamp))
1120                 ehci->stamp++;
1121         timer_action_done (ehci, TIMER_ASYNC_SHRINK);
1122 rescan:
1123         qh = ehci->async->qh_next.qh;
1124         if (likely (qh != NULL)) {
1125                 do {
1126                         /* clean any finished work for this qh */
1127                         if (!list_empty (&qh->qtd_list)
1128                                         && qh->stamp != ehci->stamp) {
1129                                 int temp;
1130
1131                                 /* unlinks could happen here; completion
1132                                  * reporting drops the lock.  rescan using
1133                                  * the latest schedule, but don't rescan
1134                                  * qhs we already finished (no looping).
1135                                  */
1136                                 qh = qh_get (qh);
1137                                 qh->stamp = ehci->stamp;
1138                                 temp = qh_completions (ehci, qh);
1139                                 qh_put (qh);
1140                                 if (temp != 0) {
1141                                         goto rescan;
1142                                 }
1143                         }
1144
1145                         /* unlink idle entries, reducing HC PCI usage as well
1146                          * as HCD schedule-scanning costs.  delay for any qh
1147                          * we just scanned, there's a not-unusual case that it
1148                          * doesn't stay idle for long.
1149                          * (plus, avoids some kind of re-activation race.)
1150                          */
1151                         if (list_empty (&qh->qtd_list)) {
1152                                 if (qh->stamp == ehci->stamp)
1153                                         action = TIMER_ASYNC_SHRINK;
1154                                 else if (!ehci->reclaim
1155                                             && qh->qh_state == QH_STATE_LINKED)
1156                                         start_unlink_async (ehci, qh);
1157                         }
1158
1159                         qh = qh->qh_next.qh;
1160                 } while (qh);
1161         }
1162         if (action == TIMER_ASYNC_SHRINK)
1163                 timer_action (ehci, TIMER_ASYNC_SHRINK);
1164 }