Merge branches 'release', 'button-sysfs', 'misc', 'mismatch', 'randconfig' and 'toshi...
[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                 if (likely(status == -EINPROGRESS))
246                         status = 0;
247                 COUNT(ehci->stats.complete);
248         }
249
250 #ifdef EHCI_URB_TRACE
251         ehci_dbg (ehci,
252                 "%s %s urb %p ep%d%s status %d len %d/%d\n",
253                 __FUNCTION__, urb->dev->devpath, urb,
254                 usb_pipeendpoint (urb->pipe),
255                 usb_pipein (urb->pipe) ? "in" : "out",
256                 status,
257                 urb->actual_length, urb->transfer_buffer_length);
258 #endif
259
260         /* complete() can reenter this HCD */
261         usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
262         spin_unlock (&ehci->lock);
263         usb_hcd_giveback_urb(ehci_to_hcd(ehci), urb, status);
264         spin_lock (&ehci->lock);
265 }
266
267 static void start_unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh);
268 static void unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh);
269
270 static void intr_deschedule (struct ehci_hcd *ehci, struct ehci_qh *qh);
271 static int qh_schedule (struct ehci_hcd *ehci, struct ehci_qh *qh);
272
273 /*
274  * Process and free completed qtds for a qh, returning URBs to drivers.
275  * Chases up to qh->hw_current.  Returns number of completions called,
276  * indicating how much "real" work we did.
277  */
278 static unsigned
279 qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
280 {
281         struct ehci_qtd         *last = NULL, *end = qh->dummy;
282         struct list_head        *entry, *tmp;
283         int                     last_status = -EINPROGRESS;
284         int                     stopped;
285         unsigned                count = 0;
286         int                     do_status = 0;
287         u8                      state;
288         u32                     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                 int             qtd_status;
313
314                 qtd = list_entry (entry, struct ehci_qtd, qtd_list);
315                 urb = qtd->urb;
316
317                 /* clean up any state from previous QTD ...*/
318                 if (last) {
319                         if (likely (last->urb != urb)) {
320                                 ehci_urb_done(ehci, last->urb, last_status);
321                                 count++;
322                                 last_status = -EINPROGRESS;
323                         }
324                         ehci_qtd_free (ehci, last);
325                         last = NULL;
326                 }
327
328                 /* ignore urbs submitted during completions we reported */
329                 if (qtd == end)
330                         break;
331
332                 /* hardware copies qtd out of qh overlay */
333                 rmb ();
334                 token = hc32_to_cpu(ehci, qtd->hw_token);
335
336                 /* always clean up qtds the hc de-activated */
337                 if ((token & QTD_STS_ACTIVE) == 0) {
338
339                         if ((token & QTD_STS_HALT) != 0) {
340                                 stopped = 1;
341
342                         /* magic dummy for some short reads; qh won't advance.
343                          * that silicon quirk can kick in with this dummy too.
344                          */
345                         } else if (IS_SHORT_READ (token)
346                                         && !(qtd->hw_alt_next
347                                                 & EHCI_LIST_END(ehci))) {
348                                 stopped = 1;
349                                 goto halt;
350                         }
351
352                 /* stop scanning when we reach qtds the hc is using */
353                 } else if (likely (!stopped
354                                 && HC_IS_RUNNING (ehci_to_hcd(ehci)->state))) {
355                         break;
356
357                 } else {
358                         stopped = 1;
359
360                         if (unlikely (!HC_IS_RUNNING (ehci_to_hcd(ehci)->state)))
361                                 last_status = -ESHUTDOWN;
362
363                         /* ignore active urbs unless some previous qtd
364                          * for the urb faulted (including short read) or
365                          * its urb was canceled.  we may patch qh or qtds.
366                          */
367                         if (likely(last_status == -EINPROGRESS &&
368                                         !urb->unlinked))
369                                 continue;
370
371                         /* issue status after short control reads */
372                         if (unlikely (do_status != 0)
373                                         && QTD_PID (token) == 0 /* OUT */) {
374                                 do_status = 0;
375                                 continue;
376                         }
377
378                         /* token in overlay may be most current */
379                         if (state == QH_STATE_IDLE
380                                         && cpu_to_hc32(ehci, qtd->qtd_dma)
381                                                 == qh->hw_current)
382                                 token = hc32_to_cpu(ehci, qh->hw_token);
383
384                         /* force halt for unlinked or blocked qh, so we'll
385                          * patch the qh later and so that completions can't
386                          * activate it while we "know" it's stopped.
387                          */
388                         if ((halt & qh->hw_token) == 0) {
389 halt:
390                                 qh->hw_token |= halt;
391                                 wmb ();
392                         }
393                 }
394
395                 /* remove it from the queue */
396                 qtd_status = qtd_copy_status(ehci, urb, qtd->length, token);
397                 if (unlikely(qtd_status == -EREMOTEIO)) {
398                         do_status = (!urb->unlinked &&
399                                         usb_pipecontrol(urb->pipe));
400                         qtd_status = 0;
401                 }
402                 if (likely(last_status == -EINPROGRESS))
403                         last_status = qtd_status;
404
405                 if (stopped && qtd->qtd_list.prev != &qh->qtd_list) {
406                         last = list_entry (qtd->qtd_list.prev,
407                                         struct ehci_qtd, qtd_list);
408                         last->hw_next = qtd->hw_next;
409                 }
410                 list_del (&qtd->qtd_list);
411                 last = qtd;
412         }
413
414         /* last urb's completion might still need calling */
415         if (likely (last != NULL)) {
416                 ehci_urb_done(ehci, last->urb, last_status);
417                 count++;
418                 ehci_qtd_free (ehci, last);
419         }
420
421         /* restore original state; caller must unlink or relink */
422         qh->qh_state = state;
423
424         /* be sure the hardware's done with the qh before refreshing
425          * it after fault cleanup, or recovering from silicon wrongly
426          * overlaying the dummy qtd (which reduces DMA chatter).
427          */
428         if (stopped != 0 || qh->hw_qtd_next == EHCI_LIST_END(ehci)) {
429                 switch (state) {
430                 case QH_STATE_IDLE:
431                         qh_refresh(ehci, qh);
432                         break;
433                 case QH_STATE_LINKED:
434                         /* should be rare for periodic transfers,
435                          * except maybe high bandwidth ...
436                          */
437                         if ((cpu_to_hc32(ehci, QH_SMASK)
438                                         & qh->hw_info2) != 0) {
439                                 intr_deschedule (ehci, qh);
440                                 (void) qh_schedule (ehci, qh);
441                         } else
442                                 unlink_async (ehci, qh);
443                         break;
444                 /* otherwise, unlink already started */
445                 }
446         }
447
448         return count;
449 }
450
451 /*-------------------------------------------------------------------------*/
452
453 // high bandwidth multiplier, as encoded in highspeed endpoint descriptors
454 #define hb_mult(wMaxPacketSize) (1 + (((wMaxPacketSize) >> 11) & 0x03))
455 // ... and packet size, for any kind of endpoint descriptor
456 #define max_packet(wMaxPacketSize) ((wMaxPacketSize) & 0x07ff)
457
458 /*
459  * reverse of qh_urb_transaction:  free a list of TDs.
460  * used for cleanup after errors, before HC sees an URB's TDs.
461  */
462 static void qtd_list_free (
463         struct ehci_hcd         *ehci,
464         struct urb              *urb,
465         struct list_head        *qtd_list
466 ) {
467         struct list_head        *entry, *temp;
468
469         list_for_each_safe (entry, temp, qtd_list) {
470                 struct ehci_qtd *qtd;
471
472                 qtd = list_entry (entry, struct ehci_qtd, qtd_list);
473                 list_del (&qtd->qtd_list);
474                 ehci_qtd_free (ehci, qtd);
475         }
476 }
477
478 /*
479  * create a list of filled qtds for this URB; won't link into qh.
480  */
481 static struct list_head *
482 qh_urb_transaction (
483         struct ehci_hcd         *ehci,
484         struct urb              *urb,
485         struct list_head        *head,
486         gfp_t                   flags
487 ) {
488         struct ehci_qtd         *qtd, *qtd_prev;
489         dma_addr_t              buf;
490         int                     len, maxpacket;
491         int                     is_input;
492         u32                     token;
493
494         /*
495          * URBs map to sequences of QTDs:  one logical transaction
496          */
497         qtd = ehci_qtd_alloc (ehci, flags);
498         if (unlikely (!qtd))
499                 return NULL;
500         list_add_tail (&qtd->qtd_list, head);
501         qtd->urb = urb;
502
503         token = QTD_STS_ACTIVE;
504         token |= (EHCI_TUNE_CERR << 10);
505         /* for split transactions, SplitXState initialized to zero */
506
507         len = urb->transfer_buffer_length;
508         is_input = usb_pipein (urb->pipe);
509         if (usb_pipecontrol (urb->pipe)) {
510                 /* SETUP pid */
511                 qtd_fill(ehci, qtd, urb->setup_dma,
512                                 sizeof (struct usb_ctrlrequest),
513                                 token | (2 /* "setup" */ << 8), 8);
514
515                 /* ... and always at least one more pid */
516                 token ^= QTD_TOGGLE;
517                 qtd_prev = qtd;
518                 qtd = ehci_qtd_alloc (ehci, flags);
519                 if (unlikely (!qtd))
520                         goto cleanup;
521                 qtd->urb = urb;
522                 qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
523                 list_add_tail (&qtd->qtd_list, head);
524
525                 /* for zero length DATA stages, STATUS is always IN */
526                 if (len == 0)
527                         token |= (1 /* "in" */ << 8);
528         }
529
530         /*
531          * data transfer stage:  buffer setup
532          */
533         buf = urb->transfer_dma;
534
535         if (is_input)
536                 token |= (1 /* "in" */ << 8);
537         /* else it's already initted to "out" pid (0 << 8) */
538
539         maxpacket = max_packet(usb_maxpacket(urb->dev, urb->pipe, !is_input));
540
541         /*
542          * buffer gets wrapped in one or more qtds;
543          * last one may be "short" (including zero len)
544          * and may serve as a control status ack
545          */
546         for (;;) {
547                 int this_qtd_len;
548
549                 this_qtd_len = qtd_fill(ehci, qtd, buf, len, token, maxpacket);
550                 len -= this_qtd_len;
551                 buf += this_qtd_len;
552                 if (is_input)
553                         qtd->hw_alt_next = ehci->async->hw_alt_next;
554
555                 /* qh makes control packets use qtd toggle; maybe switch it */
556                 if ((maxpacket & (this_qtd_len + (maxpacket - 1))) == 0)
557                         token ^= QTD_TOGGLE;
558
559                 if (likely (len <= 0))
560                         break;
561
562                 qtd_prev = qtd;
563                 qtd = ehci_qtd_alloc (ehci, flags);
564                 if (unlikely (!qtd))
565                         goto cleanup;
566                 qtd->urb = urb;
567                 qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
568                 list_add_tail (&qtd->qtd_list, head);
569         }
570
571         /* unless the bulk/interrupt caller wants a chance to clean
572          * up after short reads, hc should advance qh past this urb
573          */
574         if (likely ((urb->transfer_flags & URB_SHORT_NOT_OK) == 0
575                                 || usb_pipecontrol (urb->pipe)))
576                 qtd->hw_alt_next = EHCI_LIST_END(ehci);
577
578         /*
579          * control requests may need a terminating data "status" ack;
580          * bulk ones may need a terminating short packet (zero length).
581          */
582         if (likely (urb->transfer_buffer_length != 0)) {
583                 int     one_more = 0;
584
585                 if (usb_pipecontrol (urb->pipe)) {
586                         one_more = 1;
587                         token ^= 0x0100;        /* "in" <--> "out"  */
588                         token |= QTD_TOGGLE;    /* force DATA1 */
589                 } else if (usb_pipebulk (urb->pipe)
590                                 && (urb->transfer_flags & URB_ZERO_PACKET)
591                                 && !(urb->transfer_buffer_length % maxpacket)) {
592                         one_more = 1;
593                 }
594                 if (one_more) {
595                         qtd_prev = qtd;
596                         qtd = ehci_qtd_alloc (ehci, flags);
597                         if (unlikely (!qtd))
598                                 goto cleanup;
599                         qtd->urb = urb;
600                         qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
601                         list_add_tail (&qtd->qtd_list, head);
602
603                         /* never any data in such packets */
604                         qtd_fill(ehci, qtd, 0, 0, token, 0);
605                 }
606         }
607
608         /* by default, enable interrupt on urb completion */
609         if (likely (!(urb->transfer_flags & URB_NO_INTERRUPT)))
610                 qtd->hw_token |= cpu_to_hc32(ehci, QTD_IOC);
611         return head;
612
613 cleanup:
614         qtd_list_free (ehci, urb, head);
615         return NULL;
616 }
617
618 /*-------------------------------------------------------------------------*/
619
620 // Would be best to create all qh's from config descriptors,
621 // when each interface/altsetting is established.  Unlink
622 // any previous qh and cancel its urbs first; endpoints are
623 // implicitly reset then (data toggle too).
624 // That'd mean updating how usbcore talks to HCDs. (2.7?)
625
626
627 /*
628  * Each QH holds a qtd list; a QH is used for everything except iso.
629  *
630  * For interrupt urbs, the scheduler must set the microframe scheduling
631  * mask(s) each time the QH gets scheduled.  For highspeed, that's
632  * just one microframe in the s-mask.  For split interrupt transactions
633  * there are additional complications: c-mask, maybe FSTNs.
634  */
635 static struct ehci_qh *
636 qh_make (
637         struct ehci_hcd         *ehci,
638         struct urb              *urb,
639         gfp_t                   flags
640 ) {
641         struct ehci_qh          *qh = ehci_qh_alloc (ehci, flags);
642         u32                     info1 = 0, info2 = 0;
643         int                     is_input, type;
644         int                     maxp = 0;
645         struct usb_tt           *tt = urb->dev->tt;
646
647         if (!qh)
648                 return qh;
649
650         /*
651          * init endpoint/device data for this QH
652          */
653         info1 |= usb_pipeendpoint (urb->pipe) << 8;
654         info1 |= usb_pipedevice (urb->pipe) << 0;
655
656         is_input = usb_pipein (urb->pipe);
657         type = usb_pipetype (urb->pipe);
658         maxp = usb_maxpacket (urb->dev, urb->pipe, !is_input);
659
660         /* Compute interrupt scheduling parameters just once, and save.
661          * - allowing for high bandwidth, how many nsec/uframe are used?
662          * - split transactions need a second CSPLIT uframe; same question
663          * - splits also need a schedule gap (for full/low speed I/O)
664          * - qh has a polling interval
665          *
666          * For control/bulk requests, the HC or TT handles these.
667          */
668         if (type == PIPE_INTERRUPT) {
669                 qh->usecs = NS_TO_US(usb_calc_bus_time(USB_SPEED_HIGH,
670                                 is_input, 0,
671                                 hb_mult(maxp) * max_packet(maxp)));
672                 qh->start = NO_FRAME;
673
674                 if (urb->dev->speed == USB_SPEED_HIGH) {
675                         qh->c_usecs = 0;
676                         qh->gap_uf = 0;
677
678                         qh->period = urb->interval >> 3;
679                         if (qh->period == 0 && urb->interval != 1) {
680                                 /* NOTE interval 2 or 4 uframes could work.
681                                  * But interval 1 scheduling is simpler, and
682                                  * includes high bandwidth.
683                                  */
684                                 dbg ("intr period %d uframes, NYET!",
685                                                 urb->interval);
686                                 goto done;
687                         }
688                 } else {
689                         int             think_time;
690
691                         /* gap is f(FS/LS transfer times) */
692                         qh->gap_uf = 1 + usb_calc_bus_time (urb->dev->speed,
693                                         is_input, 0, maxp) / (125 * 1000);
694
695                         /* FIXME this just approximates SPLIT/CSPLIT times */
696                         if (is_input) {         // SPLIT, gap, CSPLIT+DATA
697                                 qh->c_usecs = qh->usecs + HS_USECS (0);
698                                 qh->usecs = HS_USECS (1);
699                         } else {                // SPLIT+DATA, gap, CSPLIT
700                                 qh->usecs += HS_USECS (1);
701                                 qh->c_usecs = HS_USECS (0);
702                         }
703
704                         think_time = tt ? tt->think_time : 0;
705                         qh->tt_usecs = NS_TO_US (think_time +
706                                         usb_calc_bus_time (urb->dev->speed,
707                                         is_input, 0, max_packet (maxp)));
708                         qh->period = urb->interval;
709                 }
710         }
711
712         /* support for tt scheduling, and access to toggles */
713         qh->dev = urb->dev;
714
715         /* using TT? */
716         switch (urb->dev->speed) {
717         case USB_SPEED_LOW:
718                 info1 |= (1 << 12);     /* EPS "low" */
719                 /* FALL THROUGH */
720
721         case USB_SPEED_FULL:
722                 /* EPS 0 means "full" */
723                 if (type != PIPE_INTERRUPT)
724                         info1 |= (EHCI_TUNE_RL_TT << 28);
725                 if (type == PIPE_CONTROL) {
726                         info1 |= (1 << 27);     /* for TT */
727                         info1 |= 1 << 14;       /* toggle from qtd */
728                 }
729                 info1 |= maxp << 16;
730
731                 info2 |= (EHCI_TUNE_MULT_TT << 30);
732
733                 /* Some Freescale processors have an erratum in which the
734                  * port number in the queue head was 0..N-1 instead of 1..N.
735                  */
736                 if (ehci_has_fsl_portno_bug(ehci))
737                         info2 |= (urb->dev->ttport-1) << 23;
738                 else
739                         info2 |= urb->dev->ttport << 23;
740
741                 /* set the address of the TT; for TDI's integrated
742                  * root hub tt, leave it zeroed.
743                  */
744                 if (tt && tt->hub != ehci_to_hcd(ehci)->self.root_hub)
745                         info2 |= tt->hub->devnum << 16;
746
747                 /* NOTE:  if (PIPE_INTERRUPT) { scheduler sets c-mask } */
748
749                 break;
750
751         case USB_SPEED_HIGH:            /* no TT involved */
752                 info1 |= (2 << 12);     /* EPS "high" */
753                 if (type == PIPE_CONTROL) {
754                         info1 |= (EHCI_TUNE_RL_HS << 28);
755                         info1 |= 64 << 16;      /* usb2 fixed maxpacket */
756                         info1 |= 1 << 14;       /* toggle from qtd */
757                         info2 |= (EHCI_TUNE_MULT_HS << 30);
758                 } else if (type == PIPE_BULK) {
759                         info1 |= (EHCI_TUNE_RL_HS << 28);
760                         info1 |= 512 << 16;     /* usb2 fixed maxpacket */
761                         info2 |= (EHCI_TUNE_MULT_HS << 30);
762                 } else {                /* PIPE_INTERRUPT */
763                         info1 |= max_packet (maxp) << 16;
764                         info2 |= hb_mult (maxp) << 30;
765                 }
766                 break;
767         default:
768                 dbg ("bogus dev %p speed %d", urb->dev, urb->dev->speed);
769 done:
770                 qh_put (qh);
771                 return NULL;
772         }
773
774         /* NOTE:  if (PIPE_INTERRUPT) { scheduler sets s-mask } */
775
776         /* init as live, toggle clear, advance to dummy */
777         qh->qh_state = QH_STATE_IDLE;
778         qh->hw_info1 = cpu_to_hc32(ehci, info1);
779         qh->hw_info2 = cpu_to_hc32(ehci, info2);
780         usb_settoggle (urb->dev, usb_pipeendpoint (urb->pipe), !is_input, 1);
781         qh_refresh (ehci, qh);
782         return qh;
783 }
784
785 /*-------------------------------------------------------------------------*/
786
787 /* move qh (and its qtds) onto async queue; maybe enable queue.  */
788
789 static void qh_link_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
790 {
791         __hc32          dma = QH_NEXT(ehci, qh->qh_dma);
792         struct ehci_qh  *head;
793
794         /* (re)start the async schedule? */
795         head = ehci->async;
796         timer_action_done (ehci, TIMER_ASYNC_OFF);
797         if (!head->qh_next.qh) {
798                 u32     cmd = ehci_readl(ehci, &ehci->regs->command);
799
800                 if (!(cmd & CMD_ASE)) {
801                         /* in case a clear of CMD_ASE didn't take yet */
802                         (void)handshake(ehci, &ehci->regs->status,
803                                         STS_ASS, 0, 150);
804                         cmd |= CMD_ASE | CMD_RUN;
805                         ehci_writel(ehci, cmd, &ehci->regs->command);
806                         ehci_to_hcd(ehci)->state = HC_STATE_RUNNING;
807                         /* posted write need not be known to HC yet ... */
808                 }
809         }
810
811         /* clear halt and/or toggle; and maybe recover from silicon quirk */
812         if (qh->qh_state == QH_STATE_IDLE)
813                 qh_refresh (ehci, qh);
814
815         /* splice right after start */
816         qh->qh_next = head->qh_next;
817         qh->hw_next = head->hw_next;
818         wmb ();
819
820         head->qh_next.qh = qh;
821         head->hw_next = dma;
822
823         qh->qh_state = QH_STATE_LINKED;
824         /* qtd completions reported later by interrupt */
825 }
826
827 /*-------------------------------------------------------------------------*/
828
829 /*
830  * For control/bulk/interrupt, return QH with these TDs appended.
831  * Allocates and initializes the QH if necessary.
832  * Returns null if it can't allocate a QH it needs to.
833  * If the QH has TDs (urbs) already, that's great.
834  */
835 static struct ehci_qh *qh_append_tds (
836         struct ehci_hcd         *ehci,
837         struct urb              *urb,
838         struct list_head        *qtd_list,
839         int                     epnum,
840         void                    **ptr
841 )
842 {
843         struct ehci_qh          *qh = NULL;
844         u32                     qh_addr_mask = cpu_to_hc32(ehci, 0x7f);
845
846         qh = (struct ehci_qh *) *ptr;
847         if (unlikely (qh == NULL)) {
848                 /* can't sleep here, we have ehci->lock... */
849                 qh = qh_make (ehci, urb, GFP_ATOMIC);
850                 *ptr = qh;
851         }
852         if (likely (qh != NULL)) {
853                 struct ehci_qtd *qtd;
854
855                 if (unlikely (list_empty (qtd_list)))
856                         qtd = NULL;
857                 else
858                         qtd = list_entry (qtd_list->next, struct ehci_qtd,
859                                         qtd_list);
860
861                 /* control qh may need patching ... */
862                 if (unlikely (epnum == 0)) {
863
864                         /* usb_reset_device() briefly reverts to address 0 */
865                         if (usb_pipedevice (urb->pipe) == 0)
866                                 qh->hw_info1 &= ~qh_addr_mask;
867                 }
868
869                 /* just one way to queue requests: swap with the dummy qtd.
870                  * only hc or qh_refresh() ever modify the overlay.
871                  */
872                 if (likely (qtd != NULL)) {
873                         struct ehci_qtd         *dummy;
874                         dma_addr_t              dma;
875                         __hc32                  token;
876
877                         /* to avoid racing the HC, use the dummy td instead of
878                          * the first td of our list (becomes new dummy).  both
879                          * tds stay deactivated until we're done, when the
880                          * HC is allowed to fetch the old dummy (4.10.2).
881                          */
882                         token = qtd->hw_token;
883                         qtd->hw_token = HALT_BIT(ehci);
884                         wmb ();
885                         dummy = qh->dummy;
886
887                         dma = dummy->qtd_dma;
888                         *dummy = *qtd;
889                         dummy->qtd_dma = dma;
890
891                         list_del (&qtd->qtd_list);
892                         list_add (&dummy->qtd_list, qtd_list);
893                         __list_splice (qtd_list, qh->qtd_list.prev);
894
895                         ehci_qtd_init(ehci, qtd, qtd->qtd_dma);
896                         qh->dummy = qtd;
897
898                         /* hc must see the new dummy at list end */
899                         dma = qtd->qtd_dma;
900                         qtd = list_entry (qh->qtd_list.prev,
901                                         struct ehci_qtd, qtd_list);
902                         qtd->hw_next = QTD_NEXT(ehci, dma);
903
904                         /* let the hc process these next qtds */
905                         wmb ();
906                         dummy->hw_token = token;
907
908                         urb->hcpriv = qh_get (qh);
909                 }
910         }
911         return qh;
912 }
913
914 /*-------------------------------------------------------------------------*/
915
916 static int
917 submit_async (
918         struct ehci_hcd         *ehci,
919         struct urb              *urb,
920         struct list_head        *qtd_list,
921         gfp_t                   mem_flags
922 ) {
923         struct ehci_qtd         *qtd;
924         int                     epnum;
925         unsigned long           flags;
926         struct ehci_qh          *qh = NULL;
927         int                     rc;
928
929         qtd = list_entry (qtd_list->next, struct ehci_qtd, qtd_list);
930         epnum = urb->ep->desc.bEndpointAddress;
931
932 #ifdef EHCI_URB_TRACE
933         ehci_dbg (ehci,
934                 "%s %s urb %p ep%d%s len %d, qtd %p [qh %p]\n",
935                 __FUNCTION__, urb->dev->devpath, urb,
936                 epnum & 0x0f, (epnum & USB_DIR_IN) ? "in" : "out",
937                 urb->transfer_buffer_length,
938                 qtd, urb->ep->hcpriv);
939 #endif
940
941         spin_lock_irqsave (&ehci->lock, flags);
942         if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE,
943                                &ehci_to_hcd(ehci)->flags))) {
944                 rc = -ESHUTDOWN;
945                 goto done;
946         }
947         rc = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
948         if (unlikely(rc))
949                 goto done;
950
951         qh = qh_append_tds(ehci, urb, qtd_list, epnum, &urb->ep->hcpriv);
952         if (unlikely(qh == NULL)) {
953                 usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
954                 rc = -ENOMEM;
955                 goto done;
956         }
957
958         /* Control/bulk operations through TTs don't need scheduling,
959          * the HC and TT handle it when the TT has a buffer ready.
960          */
961         if (likely (qh->qh_state == QH_STATE_IDLE))
962                 qh_link_async (ehci, qh_get (qh));
963  done:
964         spin_unlock_irqrestore (&ehci->lock, flags);
965         if (unlikely (qh == NULL))
966                 qtd_list_free (ehci, urb, qtd_list);
967         return rc;
968 }
969
970 /*-------------------------------------------------------------------------*/
971
972 /* the async qh for the qtds being reclaimed are now unlinked from the HC */
973
974 static void end_unlink_async (struct ehci_hcd *ehci)
975 {
976         struct ehci_qh          *qh = ehci->reclaim;
977         struct ehci_qh          *next;
978
979         iaa_watchdog_done(ehci);
980
981         // qh->hw_next = cpu_to_hc32(qh->qh_dma);
982         qh->qh_state = QH_STATE_IDLE;
983         qh->qh_next.qh = NULL;
984         qh_put (qh);                    // refcount from reclaim
985
986         /* other unlink(s) may be pending (in QH_STATE_UNLINK_WAIT) */
987         next = qh->reclaim;
988         ehci->reclaim = next;
989         qh->reclaim = NULL;
990
991         qh_completions (ehci, qh);
992
993         if (!list_empty (&qh->qtd_list)
994                         && HC_IS_RUNNING (ehci_to_hcd(ehci)->state))
995                 qh_link_async (ehci, qh);
996         else {
997                 qh_put (qh);            // refcount from async list
998
999                 /* it's not free to turn the async schedule on/off; leave it
1000                  * active but idle for a while once it empties.
1001                  */
1002                 if (HC_IS_RUNNING (ehci_to_hcd(ehci)->state)
1003                                 && ehci->async->qh_next.qh == NULL)
1004                         timer_action (ehci, TIMER_ASYNC_OFF);
1005         }
1006
1007         if (next) {
1008                 ehci->reclaim = NULL;
1009                 start_unlink_async (ehci, next);
1010         }
1011 }
1012
1013 /* makes sure the async qh will become idle */
1014 /* caller must own ehci->lock */
1015
1016 static void start_unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
1017 {
1018         int             cmd = ehci_readl(ehci, &ehci->regs->command);
1019         struct ehci_qh  *prev;
1020
1021 #ifdef DEBUG
1022         assert_spin_locked(&ehci->lock);
1023         if (ehci->reclaim
1024                         || (qh->qh_state != QH_STATE_LINKED
1025                                 && qh->qh_state != QH_STATE_UNLINK_WAIT)
1026                         )
1027                 BUG ();
1028 #endif
1029
1030         /* stop async schedule right now? */
1031         if (unlikely (qh == ehci->async)) {
1032                 /* can't get here without STS_ASS set */
1033                 if (ehci_to_hcd(ehci)->state != HC_STATE_HALT
1034                                 && !ehci->reclaim) {
1035                         /* ... and CMD_IAAD clear */
1036                         ehci_writel(ehci, cmd & ~CMD_ASE,
1037                                     &ehci->regs->command);
1038                         wmb ();
1039                         // handshake later, if we need to
1040                         timer_action_done (ehci, TIMER_ASYNC_OFF);
1041                 }
1042                 return;
1043         }
1044
1045         qh->qh_state = QH_STATE_UNLINK;
1046         ehci->reclaim = qh = qh_get (qh);
1047
1048         prev = ehci->async;
1049         while (prev->qh_next.qh != qh)
1050                 prev = prev->qh_next.qh;
1051
1052         prev->hw_next = qh->hw_next;
1053         prev->qh_next = qh->qh_next;
1054         wmb ();
1055
1056         if (unlikely (ehci_to_hcd(ehci)->state == HC_STATE_HALT)) {
1057                 /* if (unlikely (qh->reclaim != 0))
1058                  *      this will recurse, probably not much
1059                  */
1060                 end_unlink_async (ehci);
1061                 return;
1062         }
1063
1064         cmd |= CMD_IAAD;
1065         ehci_writel(ehci, cmd, &ehci->regs->command);
1066         (void)ehci_readl(ehci, &ehci->regs->command);
1067         iaa_watchdog_start(ehci);
1068 }
1069
1070 /*-------------------------------------------------------------------------*/
1071
1072 static void scan_async (struct ehci_hcd *ehci)
1073 {
1074         struct ehci_qh          *qh;
1075         enum ehci_timer_action  action = TIMER_IO_WATCHDOG;
1076
1077         if (!++(ehci->stamp))
1078                 ehci->stamp++;
1079         timer_action_done (ehci, TIMER_ASYNC_SHRINK);
1080 rescan:
1081         qh = ehci->async->qh_next.qh;
1082         if (likely (qh != NULL)) {
1083                 do {
1084                         /* clean any finished work for this qh */
1085                         if (!list_empty (&qh->qtd_list)
1086                                         && qh->stamp != ehci->stamp) {
1087                                 int temp;
1088
1089                                 /* unlinks could happen here; completion
1090                                  * reporting drops the lock.  rescan using
1091                                  * the latest schedule, but don't rescan
1092                                  * qhs we already finished (no looping).
1093                                  */
1094                                 qh = qh_get (qh);
1095                                 qh->stamp = ehci->stamp;
1096                                 temp = qh_completions (ehci, qh);
1097                                 qh_put (qh);
1098                                 if (temp != 0) {
1099                                         goto rescan;
1100                                 }
1101                         }
1102
1103                         /* unlink idle entries, reducing HC PCI usage as well
1104                          * as HCD schedule-scanning costs.  delay for any qh
1105                          * we just scanned, there's a not-unusual case that it
1106                          * doesn't stay idle for long.
1107                          * (plus, avoids some kind of re-activation race.)
1108                          */
1109                         if (list_empty (&qh->qtd_list)) {
1110                                 if (qh->stamp == ehci->stamp)
1111                                         action = TIMER_ASYNC_SHRINK;
1112                                 else if (!ehci->reclaim
1113                                             && qh->qh_state == QH_STATE_LINKED)
1114                                         start_unlink_async (ehci, qh);
1115                         }
1116
1117                         qh = qh->qh_next.qh;
1118                 } while (qh);
1119         }
1120         if (action == TIMER_ASYNC_SHRINK)
1121                 timer_action (ehci, TIMER_ASYNC_SHRINK);
1122 }