Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx
[linux-2.6] / drivers / usb / host / ehci-sched.c
1 /*
2  * Copyright (c) 2001-2004 by David Brownell
3  * Copyright (c) 2003 Michal Sojka, for high-speed iso transfers
4  *
5  * This program is free software; you can redistribute it and/or modify it
6  * under the terms of the GNU General Public License as published by the
7  * Free Software Foundation; either version 2 of the License, or (at your
8  * option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful, but
11  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
12  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
13  * for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software Foundation,
17  * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18  */
19
20 /* this file is part of ehci-hcd.c */
21
22 /*-------------------------------------------------------------------------*/
23
24 /*
25  * EHCI scheduled transaction support:  interrupt, iso, split iso
26  * These are called "periodic" transactions in the EHCI spec.
27  *
28  * Note that for interrupt transfers, the QH/QTD manipulation is shared
29  * with the "asynchronous" transaction support (control/bulk transfers).
30  * The only real difference is in how interrupt transfers are scheduled.
31  *
32  * For ISO, we make an "iso_stream" head to serve the same role as a QH.
33  * It keeps track of every ITD (or SITD) that's linked, and holds enough
34  * pre-calculated schedule data to make appending to the queue be quick.
35  */
36
37 static int ehci_get_frame (struct usb_hcd *hcd);
38
39 /*-------------------------------------------------------------------------*/
40
41 /*
42  * periodic_next_shadow - return "next" pointer on shadow list
43  * @periodic: host pointer to qh/itd/sitd
44  * @tag: hardware tag for type of this record
45  */
46 static union ehci_shadow *
47 periodic_next_shadow(struct ehci_hcd *ehci, union ehci_shadow *periodic,
48                 __hc32 tag)
49 {
50         switch (hc32_to_cpu(ehci, tag)) {
51         case Q_TYPE_QH:
52                 return &periodic->qh->qh_next;
53         case Q_TYPE_FSTN:
54                 return &periodic->fstn->fstn_next;
55         case Q_TYPE_ITD:
56                 return &periodic->itd->itd_next;
57         // case Q_TYPE_SITD:
58         default:
59                 return &periodic->sitd->sitd_next;
60         }
61 }
62
63 /* caller must hold ehci->lock */
64 static void periodic_unlink (struct ehci_hcd *ehci, unsigned frame, void *ptr)
65 {
66         union ehci_shadow       *prev_p = &ehci->pshadow[frame];
67         __hc32                  *hw_p = &ehci->periodic[frame];
68         union ehci_shadow       here = *prev_p;
69
70         /* find predecessor of "ptr"; hw and shadow lists are in sync */
71         while (here.ptr && here.ptr != ptr) {
72                 prev_p = periodic_next_shadow(ehci, prev_p,
73                                 Q_NEXT_TYPE(ehci, *hw_p));
74                 hw_p = here.hw_next;
75                 here = *prev_p;
76         }
77         /* an interrupt entry (at list end) could have been shared */
78         if (!here.ptr)
79                 return;
80
81         /* update shadow and hardware lists ... the old "next" pointers
82          * from ptr may still be in use, the caller updates them.
83          */
84         *prev_p = *periodic_next_shadow(ehci, &here,
85                         Q_NEXT_TYPE(ehci, *hw_p));
86         *hw_p = *here.hw_next;
87 }
88
89 /* how many of the uframe's 125 usecs are allocated? */
90 static unsigned short
91 periodic_usecs (struct ehci_hcd *ehci, unsigned frame, unsigned uframe)
92 {
93         __hc32                  *hw_p = &ehci->periodic [frame];
94         union ehci_shadow       *q = &ehci->pshadow [frame];
95         unsigned                usecs = 0;
96
97         while (q->ptr) {
98                 switch (hc32_to_cpu(ehci, Q_NEXT_TYPE(ehci, *hw_p))) {
99                 case Q_TYPE_QH:
100                         /* is it in the S-mask? */
101                         if (q->qh->hw_info2 & cpu_to_hc32(ehci, 1 << uframe))
102                                 usecs += q->qh->usecs;
103                         /* ... or C-mask? */
104                         if (q->qh->hw_info2 & cpu_to_hc32(ehci,
105                                         1 << (8 + uframe)))
106                                 usecs += q->qh->c_usecs;
107                         hw_p = &q->qh->hw_next;
108                         q = &q->qh->qh_next;
109                         break;
110                 // case Q_TYPE_FSTN:
111                 default:
112                         /* for "save place" FSTNs, count the relevant INTR
113                          * bandwidth from the previous frame
114                          */
115                         if (q->fstn->hw_prev != EHCI_LIST_END(ehci)) {
116                                 ehci_dbg (ehci, "ignoring FSTN cost ...\n");
117                         }
118                         hw_p = &q->fstn->hw_next;
119                         q = &q->fstn->fstn_next;
120                         break;
121                 case Q_TYPE_ITD:
122                         if (q->itd->hw_transaction[uframe])
123                                 usecs += q->itd->stream->usecs;
124                         hw_p = &q->itd->hw_next;
125                         q = &q->itd->itd_next;
126                         break;
127                 case Q_TYPE_SITD:
128                         /* is it in the S-mask?  (count SPLIT, DATA) */
129                         if (q->sitd->hw_uframe & cpu_to_hc32(ehci,
130                                         1 << uframe)) {
131                                 if (q->sitd->hw_fullspeed_ep &
132                                                 cpu_to_hc32(ehci, 1<<31))
133                                         usecs += q->sitd->stream->usecs;
134                                 else    /* worst case for OUT start-split */
135                                         usecs += HS_USECS_ISO (188);
136                         }
137
138                         /* ... C-mask?  (count CSPLIT, DATA) */
139                         if (q->sitd->hw_uframe &
140                                         cpu_to_hc32(ehci, 1 << (8 + uframe))) {
141                                 /* worst case for IN complete-split */
142                                 usecs += q->sitd->stream->c_usecs;
143                         }
144
145                         hw_p = &q->sitd->hw_next;
146                         q = &q->sitd->sitd_next;
147                         break;
148                 }
149         }
150 #ifdef  DEBUG
151         if (usecs > 100)
152                 ehci_err (ehci, "uframe %d sched overrun: %d usecs\n",
153                         frame * 8 + uframe, usecs);
154 #endif
155         return usecs;
156 }
157
158 /*-------------------------------------------------------------------------*/
159
160 static int same_tt (struct usb_device *dev1, struct usb_device *dev2)
161 {
162         if (!dev1->tt || !dev2->tt)
163                 return 0;
164         if (dev1->tt != dev2->tt)
165                 return 0;
166         if (dev1->tt->multi)
167                 return dev1->ttport == dev2->ttport;
168         else
169                 return 1;
170 }
171
172 #ifdef CONFIG_USB_EHCI_TT_NEWSCHED
173
174 /* Which uframe does the low/fullspeed transfer start in?
175  *
176  * The parameter is the mask of ssplits in "H-frame" terms
177  * and this returns the transfer start uframe in "B-frame" terms,
178  * which allows both to match, e.g. a ssplit in "H-frame" uframe 0
179  * will cause a transfer in "B-frame" uframe 0.  "B-frames" lag
180  * "H-frames" by 1 uframe.  See the EHCI spec sec 4.5 and figure 4.7.
181  */
182 static inline unsigned char tt_start_uframe(struct ehci_hcd *ehci, __hc32 mask)
183 {
184         unsigned char smask = QH_SMASK & hc32_to_cpu(ehci, mask);
185         if (!smask) {
186                 ehci_err(ehci, "invalid empty smask!\n");
187                 /* uframe 7 can't have bw so this will indicate failure */
188                 return 7;
189         }
190         return ffs(smask) - 1;
191 }
192
193 static const unsigned char
194 max_tt_usecs[] = { 125, 125, 125, 125, 125, 125, 30, 0 };
195
196 /* carryover low/fullspeed bandwidth that crosses uframe boundries */
197 static inline void carryover_tt_bandwidth(unsigned short tt_usecs[8])
198 {
199         int i;
200         for (i=0; i<7; i++) {
201                 if (max_tt_usecs[i] < tt_usecs[i]) {
202                         tt_usecs[i+1] += tt_usecs[i] - max_tt_usecs[i];
203                         tt_usecs[i] = max_tt_usecs[i];
204                 }
205         }
206 }
207
208 /* How many of the tt's periodic downstream 1000 usecs are allocated?
209  *
210  * While this measures the bandwidth in terms of usecs/uframe,
211  * the low/fullspeed bus has no notion of uframes, so any particular
212  * low/fullspeed transfer can "carry over" from one uframe to the next,
213  * since the TT just performs downstream transfers in sequence.
214  *
215  * For example two separate 100 usec transfers can start in the same uframe,
216  * and the second one would "carry over" 75 usecs into the next uframe.
217  */
218 static void
219 periodic_tt_usecs (
220         struct ehci_hcd *ehci,
221         struct usb_device *dev,
222         unsigned frame,
223         unsigned short tt_usecs[8]
224 )
225 {
226         __hc32                  *hw_p = &ehci->periodic [frame];
227         union ehci_shadow       *q = &ehci->pshadow [frame];
228         unsigned char           uf;
229
230         memset(tt_usecs, 0, 16);
231
232         while (q->ptr) {
233                 switch (hc32_to_cpu(ehci, Q_NEXT_TYPE(ehci, *hw_p))) {
234                 case Q_TYPE_ITD:
235                         hw_p = &q->itd->hw_next;
236                         q = &q->itd->itd_next;
237                         continue;
238                 case Q_TYPE_QH:
239                         if (same_tt(dev, q->qh->dev)) {
240                                 uf = tt_start_uframe(ehci, q->qh->hw_info2);
241                                 tt_usecs[uf] += q->qh->tt_usecs;
242                         }
243                         hw_p = &q->qh->hw_next;
244                         q = &q->qh->qh_next;
245                         continue;
246                 case Q_TYPE_SITD:
247                         if (same_tt(dev, q->sitd->urb->dev)) {
248                                 uf = tt_start_uframe(ehci, q->sitd->hw_uframe);
249                                 tt_usecs[uf] += q->sitd->stream->tt_usecs;
250                         }
251                         hw_p = &q->sitd->hw_next;
252                         q = &q->sitd->sitd_next;
253                         continue;
254                 // case Q_TYPE_FSTN:
255                 default:
256                         ehci_dbg(ehci, "ignoring periodic frame %d FSTN\n",
257                                         frame);
258                         hw_p = &q->fstn->hw_next;
259                         q = &q->fstn->fstn_next;
260                 }
261         }
262
263         carryover_tt_bandwidth(tt_usecs);
264
265         if (max_tt_usecs[7] < tt_usecs[7])
266                 ehci_err(ehci, "frame %d tt sched overrun: %d usecs\n",
267                         frame, tt_usecs[7] - max_tt_usecs[7]);
268 }
269
270 /*
271  * Return true if the device's tt's downstream bus is available for a
272  * periodic transfer of the specified length (usecs), starting at the
273  * specified frame/uframe.  Note that (as summarized in section 11.19
274  * of the usb 2.0 spec) TTs can buffer multiple transactions for each
275  * uframe.
276  *
277  * The uframe parameter is when the fullspeed/lowspeed transfer
278  * should be executed in "B-frame" terms, which is the same as the
279  * highspeed ssplit's uframe (which is in "H-frame" terms).  For example
280  * a ssplit in "H-frame" 0 causes a transfer in "B-frame" 0.
281  * See the EHCI spec sec 4.5 and fig 4.7.
282  *
283  * This checks if the full/lowspeed bus, at the specified starting uframe,
284  * has the specified bandwidth available, according to rules listed
285  * in USB 2.0 spec section 11.18.1 fig 11-60.
286  *
287  * This does not check if the transfer would exceed the max ssplit
288  * limit of 16, specified in USB 2.0 spec section 11.18.4 requirement #4,
289  * since proper scheduling limits ssplits to less than 16 per uframe.
290  */
291 static int tt_available (
292         struct ehci_hcd         *ehci,
293         unsigned                period,
294         struct usb_device       *dev,
295         unsigned                frame,
296         unsigned                uframe,
297         u16                     usecs
298 )
299 {
300         if ((period == 0) || (uframe >= 7))     /* error */
301                 return 0;
302
303         for (; frame < ehci->periodic_size; frame += period) {
304                 unsigned short tt_usecs[8];
305
306                 periodic_tt_usecs (ehci, dev, frame, tt_usecs);
307
308                 ehci_vdbg(ehci, "tt frame %d check %d usecs start uframe %d in"
309                         " schedule %d/%d/%d/%d/%d/%d/%d/%d\n",
310                         frame, usecs, uframe,
311                         tt_usecs[0], tt_usecs[1], tt_usecs[2], tt_usecs[3],
312                         tt_usecs[4], tt_usecs[5], tt_usecs[6], tt_usecs[7]);
313
314                 if (max_tt_usecs[uframe] <= tt_usecs[uframe]) {
315                         ehci_vdbg(ehci, "frame %d uframe %d fully scheduled\n",
316                                 frame, uframe);
317                         return 0;
318                 }
319
320                 /* special case for isoc transfers larger than 125us:
321                  * the first and each subsequent fully used uframe
322                  * must be empty, so as to not illegally delay
323                  * already scheduled transactions
324                  */
325                 if (125 < usecs) {
326                         int ufs = (usecs / 125) - 1;
327                         int i;
328                         for (i = uframe; i < (uframe + ufs) && i < 8; i++)
329                                 if (0 < tt_usecs[i]) {
330                                         ehci_vdbg(ehci,
331                                                 "multi-uframe xfer can't fit "
332                                                 "in frame %d uframe %d\n",
333                                                 frame, i);
334                                         return 0;
335                                 }
336                 }
337
338                 tt_usecs[uframe] += usecs;
339
340                 carryover_tt_bandwidth(tt_usecs);
341
342                 /* fail if the carryover pushed bw past the last uframe's limit */
343                 if (max_tt_usecs[7] < tt_usecs[7]) {
344                         ehci_vdbg(ehci,
345                                 "tt unavailable usecs %d frame %d uframe %d\n",
346                                 usecs, frame, uframe);
347                         return 0;
348                 }
349         }
350
351         return 1;
352 }
353
354 #else
355
356 /* return true iff the device's transaction translator is available
357  * for a periodic transfer starting at the specified frame, using
358  * all the uframes in the mask.
359  */
360 static int tt_no_collision (
361         struct ehci_hcd         *ehci,
362         unsigned                period,
363         struct usb_device       *dev,
364         unsigned                frame,
365         u32                     uf_mask
366 )
367 {
368         if (period == 0)        /* error */
369                 return 0;
370
371         /* note bandwidth wastage:  split never follows csplit
372          * (different dev or endpoint) until the next uframe.
373          * calling convention doesn't make that distinction.
374          */
375         for (; frame < ehci->periodic_size; frame += period) {
376                 union ehci_shadow       here;
377                 __hc32                  type;
378
379                 here = ehci->pshadow [frame];
380                 type = Q_NEXT_TYPE(ehci, ehci->periodic [frame]);
381                 while (here.ptr) {
382                         switch (hc32_to_cpu(ehci, type)) {
383                         case Q_TYPE_ITD:
384                                 type = Q_NEXT_TYPE(ehci, here.itd->hw_next);
385                                 here = here.itd->itd_next;
386                                 continue;
387                         case Q_TYPE_QH:
388                                 if (same_tt (dev, here.qh->dev)) {
389                                         u32             mask;
390
391                                         mask = hc32_to_cpu(ehci,
392                                                         here.qh->hw_info2);
393                                         /* "knows" no gap is needed */
394                                         mask |= mask >> 8;
395                                         if (mask & uf_mask)
396                                                 break;
397                                 }
398                                 type = Q_NEXT_TYPE(ehci, here.qh->hw_next);
399                                 here = here.qh->qh_next;
400                                 continue;
401                         case Q_TYPE_SITD:
402                                 if (same_tt (dev, here.sitd->urb->dev)) {
403                                         u16             mask;
404
405                                         mask = hc32_to_cpu(ehci, here.sitd
406                                                                 ->hw_uframe);
407                                         /* FIXME assumes no gap for IN! */
408                                         mask |= mask >> 8;
409                                         if (mask & uf_mask)
410                                                 break;
411                                 }
412                                 type = Q_NEXT_TYPE(ehci, here.sitd->hw_next);
413                                 here = here.sitd->sitd_next;
414                                 continue;
415                         // case Q_TYPE_FSTN:
416                         default:
417                                 ehci_dbg (ehci,
418                                         "periodic frame %d bogus type %d\n",
419                                         frame, type);
420                         }
421
422                         /* collision or error */
423                         return 0;
424                 }
425         }
426
427         /* no collision */
428         return 1;
429 }
430
431 #endif /* CONFIG_USB_EHCI_TT_NEWSCHED */
432
433 /*-------------------------------------------------------------------------*/
434
435 static int enable_periodic (struct ehci_hcd *ehci)
436 {
437         u32     cmd;
438         int     status;
439
440         if (ehci->periodic_sched++)
441                 return 0;
442
443         /* did clearing PSE did take effect yet?
444          * takes effect only at frame boundaries...
445          */
446         status = handshake_on_error_set_halt(ehci, &ehci->regs->status,
447                                              STS_PSS, 0, 9 * 125);
448         if (status)
449                 return status;
450
451         cmd = ehci_readl(ehci, &ehci->regs->command) | CMD_PSE;
452         ehci_writel(ehci, cmd, &ehci->regs->command);
453         /* posted write ... PSS happens later */
454         ehci_to_hcd(ehci)->state = HC_STATE_RUNNING;
455
456         /* make sure ehci_work scans these */
457         ehci->next_uframe = ehci_readl(ehci, &ehci->regs->frame_index)
458                 % (ehci->periodic_size << 3);
459         return 0;
460 }
461
462 static int disable_periodic (struct ehci_hcd *ehci)
463 {
464         u32     cmd;
465         int     status;
466
467         if (--ehci->periodic_sched)
468                 return 0;
469
470         /* did setting PSE not take effect yet?
471          * takes effect only at frame boundaries...
472          */
473         status = handshake_on_error_set_halt(ehci, &ehci->regs->status,
474                                              STS_PSS, STS_PSS, 9 * 125);
475         if (status)
476                 return status;
477
478         cmd = ehci_readl(ehci, &ehci->regs->command) & ~CMD_PSE;
479         ehci_writel(ehci, cmd, &ehci->regs->command);
480         /* posted write ... */
481
482         ehci->next_uframe = -1;
483         return 0;
484 }
485
486 /*-------------------------------------------------------------------------*/
487
488 /* periodic schedule slots have iso tds (normal or split) first, then a
489  * sparse tree for active interrupt transfers.
490  *
491  * this just links in a qh; caller guarantees uframe masks are set right.
492  * no FSTN support (yet; ehci 0.96+)
493  */
494 static int qh_link_periodic (struct ehci_hcd *ehci, struct ehci_qh *qh)
495 {
496         unsigned        i;
497         unsigned        period = qh->period;
498
499         dev_dbg (&qh->dev->dev,
500                 "link qh%d-%04x/%p start %d [%d/%d us]\n",
501                 period, hc32_to_cpup(ehci, &qh->hw_info2) & (QH_CMASK | QH_SMASK),
502                 qh, qh->start, qh->usecs, qh->c_usecs);
503
504         /* high bandwidth, or otherwise every microframe */
505         if (period == 0)
506                 period = 1;
507
508         for (i = qh->start; i < ehci->periodic_size; i += period) {
509                 union ehci_shadow       *prev = &ehci->pshadow[i];
510                 __hc32                  *hw_p = &ehci->periodic[i];
511                 union ehci_shadow       here = *prev;
512                 __hc32                  type = 0;
513
514                 /* skip the iso nodes at list head */
515                 while (here.ptr) {
516                         type = Q_NEXT_TYPE(ehci, *hw_p);
517                         if (type == cpu_to_hc32(ehci, Q_TYPE_QH))
518                                 break;
519                         prev = periodic_next_shadow(ehci, prev, type);
520                         hw_p = &here.qh->hw_next;
521                         here = *prev;
522                 }
523
524                 /* sorting each branch by period (slow-->fast)
525                  * enables sharing interior tree nodes
526                  */
527                 while (here.ptr && qh != here.qh) {
528                         if (qh->period > here.qh->period)
529                                 break;
530                         prev = &here.qh->qh_next;
531                         hw_p = &here.qh->hw_next;
532                         here = *prev;
533                 }
534                 /* link in this qh, unless some earlier pass did that */
535                 if (qh != here.qh) {
536                         qh->qh_next = here;
537                         if (here.qh)
538                                 qh->hw_next = *hw_p;
539                         wmb ();
540                         prev->qh = qh;
541                         *hw_p = QH_NEXT (ehci, qh->qh_dma);
542                 }
543         }
544         qh->qh_state = QH_STATE_LINKED;
545         qh_get (qh);
546
547         /* update per-qh bandwidth for usbfs */
548         ehci_to_hcd(ehci)->self.bandwidth_allocated += qh->period
549                 ? ((qh->usecs + qh->c_usecs) / qh->period)
550                 : (qh->usecs * 8);
551
552         /* maybe enable periodic schedule processing */
553         return enable_periodic(ehci);
554 }
555
556 static int qh_unlink_periodic(struct ehci_hcd *ehci, struct ehci_qh *qh)
557 {
558         unsigned        i;
559         unsigned        period;
560
561         // FIXME:
562         // IF this isn't high speed
563         //   and this qh is active in the current uframe
564         //   (and overlay token SplitXstate is false?)
565         // THEN
566         //   qh->hw_info1 |= __constant_cpu_to_hc32(1 << 7 /* "ignore" */);
567
568         /* high bandwidth, or otherwise part of every microframe */
569         if ((period = qh->period) == 0)
570                 period = 1;
571
572         for (i = qh->start; i < ehci->periodic_size; i += period)
573                 periodic_unlink (ehci, i, qh);
574
575         /* update per-qh bandwidth for usbfs */
576         ehci_to_hcd(ehci)->self.bandwidth_allocated -= qh->period
577                 ? ((qh->usecs + qh->c_usecs) / qh->period)
578                 : (qh->usecs * 8);
579
580         dev_dbg (&qh->dev->dev,
581                 "unlink qh%d-%04x/%p start %d [%d/%d us]\n",
582                 qh->period,
583                 hc32_to_cpup(ehci, &qh->hw_info2) & (QH_CMASK | QH_SMASK),
584                 qh, qh->start, qh->usecs, qh->c_usecs);
585
586         /* qh->qh_next still "live" to HC */
587         qh->qh_state = QH_STATE_UNLINK;
588         qh->qh_next.ptr = NULL;
589         qh_put (qh);
590
591         /* maybe turn off periodic schedule */
592         return disable_periodic(ehci);
593 }
594
595 static void intr_deschedule (struct ehci_hcd *ehci, struct ehci_qh *qh)
596 {
597         unsigned        wait;
598
599         qh_unlink_periodic (ehci, qh);
600
601         /* simple/paranoid:  always delay, expecting the HC needs to read
602          * qh->hw_next or finish a writeback after SPLIT/CSPLIT ... and
603          * expect khubd to clean up after any CSPLITs we won't issue.
604          * active high speed queues may need bigger delays...
605          */
606         if (list_empty (&qh->qtd_list)
607                         || (cpu_to_hc32(ehci, QH_CMASK)
608                                         & qh->hw_info2) != 0)
609                 wait = 2;
610         else
611                 wait = 55;      /* worst case: 3 * 1024 */
612
613         udelay (wait);
614         qh->qh_state = QH_STATE_IDLE;
615         qh->hw_next = EHCI_LIST_END(ehci);
616         wmb ();
617 }
618
619 /*-------------------------------------------------------------------------*/
620
621 static int check_period (
622         struct ehci_hcd *ehci,
623         unsigned        frame,
624         unsigned        uframe,
625         unsigned        period,
626         unsigned        usecs
627 ) {
628         int             claimed;
629
630         /* complete split running into next frame?
631          * given FSTN support, we could sometimes check...
632          */
633         if (uframe >= 8)
634                 return 0;
635
636         /*
637          * 80% periodic == 100 usec/uframe available
638          * convert "usecs we need" to "max already claimed"
639          */
640         usecs = 100 - usecs;
641
642         /* we "know" 2 and 4 uframe intervals were rejected; so
643          * for period 0, check _every_ microframe in the schedule.
644          */
645         if (unlikely (period == 0)) {
646                 do {
647                         for (uframe = 0; uframe < 7; uframe++) {
648                                 claimed = periodic_usecs (ehci, frame, uframe);
649                                 if (claimed > usecs)
650                                         return 0;
651                         }
652                 } while ((frame += 1) < ehci->periodic_size);
653
654         /* just check the specified uframe, at that period */
655         } else {
656                 do {
657                         claimed = periodic_usecs (ehci, frame, uframe);
658                         if (claimed > usecs)
659                                 return 0;
660                 } while ((frame += period) < ehci->periodic_size);
661         }
662
663         // success!
664         return 1;
665 }
666
667 static int check_intr_schedule (
668         struct ehci_hcd         *ehci,
669         unsigned                frame,
670         unsigned                uframe,
671         const struct ehci_qh    *qh,
672         __hc32                  *c_maskp
673 )
674 {
675         int             retval = -ENOSPC;
676         u8              mask = 0;
677
678         if (qh->c_usecs && uframe >= 6)         /* FSTN territory? */
679                 goto done;
680
681         if (!check_period (ehci, frame, uframe, qh->period, qh->usecs))
682                 goto done;
683         if (!qh->c_usecs) {
684                 retval = 0;
685                 *c_maskp = 0;
686                 goto done;
687         }
688
689 #ifdef CONFIG_USB_EHCI_TT_NEWSCHED
690         if (tt_available (ehci, qh->period, qh->dev, frame, uframe,
691                                 qh->tt_usecs)) {
692                 unsigned i;
693
694                 /* TODO : this may need FSTN for SSPLIT in uframe 5. */
695                 for (i=uframe+1; i<8 && i<uframe+4; i++)
696                         if (!check_period (ehci, frame, i,
697                                                 qh->period, qh->c_usecs))
698                                 goto done;
699                         else
700                                 mask |= 1 << i;
701
702                 retval = 0;
703
704                 *c_maskp = cpu_to_hc32(ehci, mask << 8);
705         }
706 #else
707         /* Make sure this tt's buffer is also available for CSPLITs.
708          * We pessimize a bit; probably the typical full speed case
709          * doesn't need the second CSPLIT.
710          *
711          * NOTE:  both SPLIT and CSPLIT could be checked in just
712          * one smart pass...
713          */
714         mask = 0x03 << (uframe + qh->gap_uf);
715         *c_maskp = cpu_to_hc32(ehci, mask << 8);
716
717         mask |= 1 << uframe;
718         if (tt_no_collision (ehci, qh->period, qh->dev, frame, mask)) {
719                 if (!check_period (ehci, frame, uframe + qh->gap_uf + 1,
720                                         qh->period, qh->c_usecs))
721                         goto done;
722                 if (!check_period (ehci, frame, uframe + qh->gap_uf,
723                                         qh->period, qh->c_usecs))
724                         goto done;
725                 retval = 0;
726         }
727 #endif
728 done:
729         return retval;
730 }
731
732 /* "first fit" scheduling policy used the first time through,
733  * or when the previous schedule slot can't be re-used.
734  */
735 static int qh_schedule(struct ehci_hcd *ehci, struct ehci_qh *qh)
736 {
737         int             status;
738         unsigned        uframe;
739         __hc32          c_mask;
740         unsigned        frame;          /* 0..(qh->period - 1), or NO_FRAME */
741
742         qh_refresh(ehci, qh);
743         qh->hw_next = EHCI_LIST_END(ehci);
744         frame = qh->start;
745
746         /* reuse the previous schedule slots, if we can */
747         if (frame < qh->period) {
748                 uframe = ffs(hc32_to_cpup(ehci, &qh->hw_info2) & QH_SMASK);
749                 status = check_intr_schedule (ehci, frame, --uframe,
750                                 qh, &c_mask);
751         } else {
752                 uframe = 0;
753                 c_mask = 0;
754                 status = -ENOSPC;
755         }
756
757         /* else scan the schedule to find a group of slots such that all
758          * uframes have enough periodic bandwidth available.
759          */
760         if (status) {
761                 /* "normal" case, uframing flexible except with splits */
762                 if (qh->period) {
763                         frame = qh->period - 1;
764                         do {
765                                 for (uframe = 0; uframe < 8; uframe++) {
766                                         status = check_intr_schedule (ehci,
767                                                         frame, uframe, qh,
768                                                         &c_mask);
769                                         if (status == 0)
770                                                 break;
771                                 }
772                         } while (status && frame--);
773
774                 /* qh->period == 0 means every uframe */
775                 } else {
776                         frame = 0;
777                         status = check_intr_schedule (ehci, 0, 0, qh, &c_mask);
778                 }
779                 if (status)
780                         goto done;
781                 qh->start = frame;
782
783                 /* reset S-frame and (maybe) C-frame masks */
784                 qh->hw_info2 &= cpu_to_hc32(ehci, ~(QH_CMASK | QH_SMASK));
785                 qh->hw_info2 |= qh->period
786                         ? cpu_to_hc32(ehci, 1 << uframe)
787                         : cpu_to_hc32(ehci, QH_SMASK);
788                 qh->hw_info2 |= c_mask;
789         } else
790                 ehci_dbg (ehci, "reused qh %p schedule\n", qh);
791
792         /* stuff into the periodic schedule */
793         status = qh_link_periodic (ehci, qh);
794 done:
795         return status;
796 }
797
798 static int intr_submit (
799         struct ehci_hcd         *ehci,
800         struct urb              *urb,
801         struct list_head        *qtd_list,
802         gfp_t                   mem_flags
803 ) {
804         unsigned                epnum;
805         unsigned long           flags;
806         struct ehci_qh          *qh;
807         int                     status;
808         struct list_head        empty;
809
810         /* get endpoint and transfer/schedule data */
811         epnum = urb->ep->desc.bEndpointAddress;
812
813         spin_lock_irqsave (&ehci->lock, flags);
814
815         if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE,
816                         &ehci_to_hcd(ehci)->flags))) {
817                 status = -ESHUTDOWN;
818                 goto done_not_linked;
819         }
820         status = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
821         if (unlikely(status))
822                 goto done_not_linked;
823
824         /* get qh and force any scheduling errors */
825         INIT_LIST_HEAD (&empty);
826         qh = qh_append_tds(ehci, urb, &empty, epnum, &urb->ep->hcpriv);
827         if (qh == NULL) {
828                 status = -ENOMEM;
829                 goto done;
830         }
831         if (qh->qh_state == QH_STATE_IDLE) {
832                 if ((status = qh_schedule (ehci, qh)) != 0)
833                         goto done;
834         }
835
836         /* then queue the urb's tds to the qh */
837         qh = qh_append_tds(ehci, urb, qtd_list, epnum, &urb->ep->hcpriv);
838         BUG_ON (qh == NULL);
839
840         /* ... update usbfs periodic stats */
841         ehci_to_hcd(ehci)->self.bandwidth_int_reqs++;
842
843 done:
844         if (unlikely(status))
845                 usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
846 done_not_linked:
847         spin_unlock_irqrestore (&ehci->lock, flags);
848         if (status)
849                 qtd_list_free (ehci, urb, qtd_list);
850
851         return status;
852 }
853
854 /*-------------------------------------------------------------------------*/
855
856 /* ehci_iso_stream ops work with both ITD and SITD */
857
858 static struct ehci_iso_stream *
859 iso_stream_alloc (gfp_t mem_flags)
860 {
861         struct ehci_iso_stream *stream;
862
863         stream = kzalloc(sizeof *stream, mem_flags);
864         if (likely (stream != NULL)) {
865                 INIT_LIST_HEAD(&stream->td_list);
866                 INIT_LIST_HEAD(&stream->free_list);
867                 stream->next_uframe = -1;
868                 stream->refcount = 1;
869         }
870         return stream;
871 }
872
873 static void
874 iso_stream_init (
875         struct ehci_hcd         *ehci,
876         struct ehci_iso_stream  *stream,
877         struct usb_device       *dev,
878         int                     pipe,
879         unsigned                interval
880 )
881 {
882         static const u8 smask_out [] = { 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f };
883
884         u32                     buf1;
885         unsigned                epnum, maxp;
886         int                     is_input;
887         long                    bandwidth;
888
889         /*
890          * this might be a "high bandwidth" highspeed endpoint,
891          * as encoded in the ep descriptor's wMaxPacket field
892          */
893         epnum = usb_pipeendpoint (pipe);
894         is_input = usb_pipein (pipe) ? USB_DIR_IN : 0;
895         maxp = usb_maxpacket(dev, pipe, !is_input);
896         if (is_input) {
897                 buf1 = (1 << 11);
898         } else {
899                 buf1 = 0;
900         }
901
902         /* knows about ITD vs SITD */
903         if (dev->speed == USB_SPEED_HIGH) {
904                 unsigned multi = hb_mult(maxp);
905
906                 stream->highspeed = 1;
907
908                 maxp = max_packet(maxp);
909                 buf1 |= maxp;
910                 maxp *= multi;
911
912                 stream->buf0 = cpu_to_hc32(ehci, (epnum << 8) | dev->devnum);
913                 stream->buf1 = cpu_to_hc32(ehci, buf1);
914                 stream->buf2 = cpu_to_hc32(ehci, multi);
915
916                 /* usbfs wants to report the average usecs per frame tied up
917                  * when transfers on this endpoint are scheduled ...
918                  */
919                 stream->usecs = HS_USECS_ISO (maxp);
920                 bandwidth = stream->usecs * 8;
921                 bandwidth /= interval;
922
923         } else {
924                 u32             addr;
925                 int             think_time;
926                 int             hs_transfers;
927
928                 addr = dev->ttport << 24;
929                 if (!ehci_is_TDI(ehci)
930                                 || (dev->tt->hub !=
931                                         ehci_to_hcd(ehci)->self.root_hub))
932                         addr |= dev->tt->hub->devnum << 16;
933                 addr |= epnum << 8;
934                 addr |= dev->devnum;
935                 stream->usecs = HS_USECS_ISO (maxp);
936                 think_time = dev->tt ? dev->tt->think_time : 0;
937                 stream->tt_usecs = NS_TO_US (think_time + usb_calc_bus_time (
938                                 dev->speed, is_input, 1, maxp));
939                 hs_transfers = max (1u, (maxp + 187) / 188);
940                 if (is_input) {
941                         u32     tmp;
942
943                         addr |= 1 << 31;
944                         stream->c_usecs = stream->usecs;
945                         stream->usecs = HS_USECS_ISO (1);
946                         stream->raw_mask = 1;
947
948                         /* c-mask as specified in USB 2.0 11.18.4 3.c */
949                         tmp = (1 << (hs_transfers + 2)) - 1;
950                         stream->raw_mask |= tmp << (8 + 2);
951                 } else
952                         stream->raw_mask = smask_out [hs_transfers - 1];
953                 bandwidth = stream->usecs + stream->c_usecs;
954                 bandwidth /= interval << 3;
955
956                 /* stream->splits gets created from raw_mask later */
957                 stream->address = cpu_to_hc32(ehci, addr);
958         }
959         stream->bandwidth = bandwidth;
960
961         stream->udev = dev;
962
963         stream->bEndpointAddress = is_input | epnum;
964         stream->interval = interval;
965         stream->maxp = maxp;
966 }
967
968 static void
969 iso_stream_put(struct ehci_hcd *ehci, struct ehci_iso_stream *stream)
970 {
971         stream->refcount--;
972
973         /* free whenever just a dev->ep reference remains.
974          * not like a QH -- no persistent state (toggle, halt)
975          */
976         if (stream->refcount == 1) {
977                 int             is_in;
978
979                 // BUG_ON (!list_empty(&stream->td_list));
980
981                 while (!list_empty (&stream->free_list)) {
982                         struct list_head        *entry;
983
984                         entry = stream->free_list.next;
985                         list_del (entry);
986
987                         /* knows about ITD vs SITD */
988                         if (stream->highspeed) {
989                                 struct ehci_itd         *itd;
990
991                                 itd = list_entry (entry, struct ehci_itd,
992                                                 itd_list);
993                                 dma_pool_free (ehci->itd_pool, itd,
994                                                 itd->itd_dma);
995                         } else {
996                                 struct ehci_sitd        *sitd;
997
998                                 sitd = list_entry (entry, struct ehci_sitd,
999                                                 sitd_list);
1000                                 dma_pool_free (ehci->sitd_pool, sitd,
1001                                                 sitd->sitd_dma);
1002                         }
1003                 }
1004
1005                 is_in = (stream->bEndpointAddress & USB_DIR_IN) ? 0x10 : 0;
1006                 stream->bEndpointAddress &= 0x0f;
1007                 if (stream->ep)
1008                         stream->ep->hcpriv = NULL;
1009
1010                 if (stream->rescheduled) {
1011                         ehci_info (ehci, "ep%d%s-iso rescheduled "
1012                                 "%lu times in %lu seconds\n",
1013                                 stream->bEndpointAddress, is_in ? "in" : "out",
1014                                 stream->rescheduled,
1015                                 ((jiffies - stream->start)/HZ)
1016                                 );
1017                 }
1018
1019                 kfree(stream);
1020         }
1021 }
1022
1023 static inline struct ehci_iso_stream *
1024 iso_stream_get (struct ehci_iso_stream *stream)
1025 {
1026         if (likely (stream != NULL))
1027                 stream->refcount++;
1028         return stream;
1029 }
1030
1031 static struct ehci_iso_stream *
1032 iso_stream_find (struct ehci_hcd *ehci, struct urb *urb)
1033 {
1034         unsigned                epnum;
1035         struct ehci_iso_stream  *stream;
1036         struct usb_host_endpoint *ep;
1037         unsigned long           flags;
1038
1039         epnum = usb_pipeendpoint (urb->pipe);
1040         if (usb_pipein(urb->pipe))
1041                 ep = urb->dev->ep_in[epnum];
1042         else
1043                 ep = urb->dev->ep_out[epnum];
1044
1045         spin_lock_irqsave (&ehci->lock, flags);
1046         stream = ep->hcpriv;
1047
1048         if (unlikely (stream == NULL)) {
1049                 stream = iso_stream_alloc(GFP_ATOMIC);
1050                 if (likely (stream != NULL)) {
1051                         /* dev->ep owns the initial refcount */
1052                         ep->hcpriv = stream;
1053                         stream->ep = ep;
1054                         iso_stream_init(ehci, stream, urb->dev, urb->pipe,
1055                                         urb->interval);
1056                 }
1057
1058         /* if dev->ep [epnum] is a QH, info1.maxpacket is nonzero */
1059         } else if (unlikely (stream->hw_info1 != 0)) {
1060                 ehci_dbg (ehci, "dev %s ep%d%s, not iso??\n",
1061                         urb->dev->devpath, epnum,
1062                         usb_pipein(urb->pipe) ? "in" : "out");
1063                 stream = NULL;
1064         }
1065
1066         /* caller guarantees an eventual matching iso_stream_put */
1067         stream = iso_stream_get (stream);
1068
1069         spin_unlock_irqrestore (&ehci->lock, flags);
1070         return stream;
1071 }
1072
1073 /*-------------------------------------------------------------------------*/
1074
1075 /* ehci_iso_sched ops can be ITD-only or SITD-only */
1076
1077 static struct ehci_iso_sched *
1078 iso_sched_alloc (unsigned packets, gfp_t mem_flags)
1079 {
1080         struct ehci_iso_sched   *iso_sched;
1081         int                     size = sizeof *iso_sched;
1082
1083         size += packets * sizeof (struct ehci_iso_packet);
1084         iso_sched = kzalloc(size, mem_flags);
1085         if (likely (iso_sched != NULL)) {
1086                 INIT_LIST_HEAD (&iso_sched->td_list);
1087         }
1088         return iso_sched;
1089 }
1090
1091 static inline void
1092 itd_sched_init(
1093         struct ehci_hcd         *ehci,
1094         struct ehci_iso_sched   *iso_sched,
1095         struct ehci_iso_stream  *stream,
1096         struct urb              *urb
1097 )
1098 {
1099         unsigned        i;
1100         dma_addr_t      dma = urb->transfer_dma;
1101
1102         /* how many uframes are needed for these transfers */
1103         iso_sched->span = urb->number_of_packets * stream->interval;
1104
1105         /* figure out per-uframe itd fields that we'll need later
1106          * when we fit new itds into the schedule.
1107          */
1108         for (i = 0; i < urb->number_of_packets; i++) {
1109                 struct ehci_iso_packet  *uframe = &iso_sched->packet [i];
1110                 unsigned                length;
1111                 dma_addr_t              buf;
1112                 u32                     trans;
1113
1114                 length = urb->iso_frame_desc [i].length;
1115                 buf = dma + urb->iso_frame_desc [i].offset;
1116
1117                 trans = EHCI_ISOC_ACTIVE;
1118                 trans |= buf & 0x0fff;
1119                 if (unlikely (((i + 1) == urb->number_of_packets))
1120                                 && !(urb->transfer_flags & URB_NO_INTERRUPT))
1121                         trans |= EHCI_ITD_IOC;
1122                 trans |= length << 16;
1123                 uframe->transaction = cpu_to_hc32(ehci, trans);
1124
1125                 /* might need to cross a buffer page within a uframe */
1126                 uframe->bufp = (buf & ~(u64)0x0fff);
1127                 buf += length;
1128                 if (unlikely ((uframe->bufp != (buf & ~(u64)0x0fff))))
1129                         uframe->cross = 1;
1130         }
1131 }
1132
1133 static void
1134 iso_sched_free (
1135         struct ehci_iso_stream  *stream,
1136         struct ehci_iso_sched   *iso_sched
1137 )
1138 {
1139         if (!iso_sched)
1140                 return;
1141         // caller must hold ehci->lock!
1142         list_splice (&iso_sched->td_list, &stream->free_list);
1143         kfree (iso_sched);
1144 }
1145
1146 static int
1147 itd_urb_transaction (
1148         struct ehci_iso_stream  *stream,
1149         struct ehci_hcd         *ehci,
1150         struct urb              *urb,
1151         gfp_t                   mem_flags
1152 )
1153 {
1154         struct ehci_itd         *itd;
1155         dma_addr_t              itd_dma;
1156         int                     i;
1157         unsigned                num_itds;
1158         struct ehci_iso_sched   *sched;
1159         unsigned long           flags;
1160
1161         sched = iso_sched_alloc (urb->number_of_packets, mem_flags);
1162         if (unlikely (sched == NULL))
1163                 return -ENOMEM;
1164
1165         itd_sched_init(ehci, sched, stream, urb);
1166
1167         if (urb->interval < 8)
1168                 num_itds = 1 + (sched->span + 7) / 8;
1169         else
1170                 num_itds = urb->number_of_packets;
1171
1172         /* allocate/init ITDs */
1173         spin_lock_irqsave (&ehci->lock, flags);
1174         for (i = 0; i < num_itds; i++) {
1175
1176                 /* free_list.next might be cache-hot ... but maybe
1177                  * the HC caches it too. avoid that issue for now.
1178                  */
1179
1180                 /* prefer previously-allocated itds */
1181                 if (likely (!list_empty(&stream->free_list))) {
1182                         itd = list_entry (stream->free_list.prev,
1183                                         struct ehci_itd, itd_list);
1184                         list_del (&itd->itd_list);
1185                         itd_dma = itd->itd_dma;
1186                 } else {
1187                         spin_unlock_irqrestore (&ehci->lock, flags);
1188                         itd = dma_pool_alloc (ehci->itd_pool, mem_flags,
1189                                         &itd_dma);
1190                         spin_lock_irqsave (&ehci->lock, flags);
1191                         if (!itd) {
1192                                 iso_sched_free(stream, sched);
1193                                 spin_unlock_irqrestore(&ehci->lock, flags);
1194                                 return -ENOMEM;
1195                         }
1196                 }
1197
1198                 memset (itd, 0, sizeof *itd);
1199                 itd->itd_dma = itd_dma;
1200                 list_add (&itd->itd_list, &sched->td_list);
1201         }
1202         spin_unlock_irqrestore (&ehci->lock, flags);
1203
1204         /* temporarily store schedule info in hcpriv */
1205         urb->hcpriv = sched;
1206         urb->error_count = 0;
1207         return 0;
1208 }
1209
1210 /*-------------------------------------------------------------------------*/
1211
1212 static inline int
1213 itd_slot_ok (
1214         struct ehci_hcd         *ehci,
1215         u32                     mod,
1216         u32                     uframe,
1217         u8                      usecs,
1218         u32                     period
1219 )
1220 {
1221         uframe %= period;
1222         do {
1223                 /* can't commit more than 80% periodic == 100 usec */
1224                 if (periodic_usecs (ehci, uframe >> 3, uframe & 0x7)
1225                                 > (100 - usecs))
1226                         return 0;
1227
1228                 /* we know urb->interval is 2^N uframes */
1229                 uframe += period;
1230         } while (uframe < mod);
1231         return 1;
1232 }
1233
1234 static inline int
1235 sitd_slot_ok (
1236         struct ehci_hcd         *ehci,
1237         u32                     mod,
1238         struct ehci_iso_stream  *stream,
1239         u32                     uframe,
1240         struct ehci_iso_sched   *sched,
1241         u32                     period_uframes
1242 )
1243 {
1244         u32                     mask, tmp;
1245         u32                     frame, uf;
1246
1247         mask = stream->raw_mask << (uframe & 7);
1248
1249         /* for IN, don't wrap CSPLIT into the next frame */
1250         if (mask & ~0xffff)
1251                 return 0;
1252
1253         /* this multi-pass logic is simple, but performance may
1254          * suffer when the schedule data isn't cached.
1255          */
1256
1257         /* check bandwidth */
1258         uframe %= period_uframes;
1259         do {
1260                 u32             max_used;
1261
1262                 frame = uframe >> 3;
1263                 uf = uframe & 7;
1264
1265 #ifdef CONFIG_USB_EHCI_TT_NEWSCHED
1266                 /* The tt's fullspeed bus bandwidth must be available.
1267                  * tt_available scheduling guarantees 10+% for control/bulk.
1268                  */
1269                 if (!tt_available (ehci, period_uframes << 3,
1270                                 stream->udev, frame, uf, stream->tt_usecs))
1271                         return 0;
1272 #else
1273                 /* tt must be idle for start(s), any gap, and csplit.
1274                  * assume scheduling slop leaves 10+% for control/bulk.
1275                  */
1276                 if (!tt_no_collision (ehci, period_uframes << 3,
1277                                 stream->udev, frame, mask))
1278                         return 0;
1279 #endif
1280
1281                 /* check starts (OUT uses more than one) */
1282                 max_used = 100 - stream->usecs;
1283                 for (tmp = stream->raw_mask & 0xff; tmp; tmp >>= 1, uf++) {
1284                         if (periodic_usecs (ehci, frame, uf) > max_used)
1285                                 return 0;
1286                 }
1287
1288                 /* for IN, check CSPLIT */
1289                 if (stream->c_usecs) {
1290                         uf = uframe & 7;
1291                         max_used = 100 - stream->c_usecs;
1292                         do {
1293                                 tmp = 1 << uf;
1294                                 tmp <<= 8;
1295                                 if ((stream->raw_mask & tmp) == 0)
1296                                         continue;
1297                                 if (periodic_usecs (ehci, frame, uf)
1298                                                 > max_used)
1299                                         return 0;
1300                         } while (++uf < 8);
1301                 }
1302
1303                 /* we know urb->interval is 2^N uframes */
1304                 uframe += period_uframes;
1305         } while (uframe < mod);
1306
1307         stream->splits = cpu_to_hc32(ehci, stream->raw_mask << (uframe & 7));
1308         return 1;
1309 }
1310
1311 /*
1312  * This scheduler plans almost as far into the future as it has actual
1313  * periodic schedule slots.  (Affected by TUNE_FLS, which defaults to
1314  * "as small as possible" to be cache-friendlier.)  That limits the size
1315  * transfers you can stream reliably; avoid more than 64 msec per urb.
1316  * Also avoid queue depths of less than ehci's worst irq latency (affected
1317  * by the per-urb URB_NO_INTERRUPT hint, the log2_irq_thresh module parameter,
1318  * and other factors); or more than about 230 msec total (for portability,
1319  * given EHCI_TUNE_FLS and the slop).  Or, write a smarter scheduler!
1320  */
1321
1322 #define SCHEDULE_SLOP   10      /* frames */
1323
1324 static int
1325 iso_stream_schedule (
1326         struct ehci_hcd         *ehci,
1327         struct urb              *urb,
1328         struct ehci_iso_stream  *stream
1329 )
1330 {
1331         u32                     now, start, max, period;
1332         int                     status;
1333         unsigned                mod = ehci->periodic_size << 3;
1334         struct ehci_iso_sched   *sched = urb->hcpriv;
1335
1336         if (sched->span > (mod - 8 * SCHEDULE_SLOP)) {
1337                 ehci_dbg (ehci, "iso request %p too long\n", urb);
1338                 status = -EFBIG;
1339                 goto fail;
1340         }
1341
1342         if ((stream->depth + sched->span) > mod) {
1343                 ehci_dbg (ehci, "request %p would overflow (%d+%d>%d)\n",
1344                         urb, stream->depth, sched->span, mod);
1345                 status = -EFBIG;
1346                 goto fail;
1347         }
1348
1349         now = ehci_readl(ehci, &ehci->regs->frame_index) % mod;
1350
1351         /* when's the last uframe this urb could start? */
1352         max = now + mod;
1353
1354         /* Typical case: reuse current schedule, stream is still active.
1355          * Hopefully there are no gaps from the host falling behind
1356          * (irq delays etc), but if there are we'll take the next
1357          * slot in the schedule, implicitly assuming URB_ISO_ASAP.
1358          */
1359         if (likely (!list_empty (&stream->td_list))) {
1360                 start = stream->next_uframe;
1361                 if (start < now)
1362                         start += mod;
1363
1364                 /* Fell behind (by up to twice the slop amount)? */
1365                 if (start >= max - 2 * 8 * SCHEDULE_SLOP)
1366                         start += stream->interval * DIV_ROUND_UP(
1367                                         max - start, stream->interval) - mod;
1368
1369                 /* Tried to schedule too far into the future? */
1370                 if (unlikely((start + sched->span) >= max)) {
1371                         status = -EFBIG;
1372                         goto fail;
1373                 }
1374                 goto ready;
1375         }
1376
1377         /* need to schedule; when's the next (u)frame we could start?
1378          * this is bigger than ehci->i_thresh allows; scheduling itself
1379          * isn't free, the slop should handle reasonably slow cpus.  it
1380          * can also help high bandwidth if the dma and irq loads don't
1381          * jump until after the queue is primed.
1382          */
1383         start = SCHEDULE_SLOP * 8 + (now & ~0x07);
1384         start %= mod;
1385         stream->next_uframe = start;
1386
1387         /* NOTE:  assumes URB_ISO_ASAP, to limit complexity/bugs */
1388
1389         period = urb->interval;
1390         if (!stream->highspeed)
1391                 period <<= 3;
1392
1393         /* find a uframe slot with enough bandwidth */
1394         for (; start < (stream->next_uframe + period); start++) {
1395                 int             enough_space;
1396
1397                 /* check schedule: enough space? */
1398                 if (stream->highspeed)
1399                         enough_space = itd_slot_ok (ehci, mod, start,
1400                                         stream->usecs, period);
1401                 else {
1402                         if ((start % 8) >= 6)
1403                                 continue;
1404                         enough_space = sitd_slot_ok (ehci, mod, stream,
1405                                         start, sched, period);
1406                 }
1407
1408                 /* schedule it here if there's enough bandwidth */
1409                 if (enough_space) {
1410                         stream->next_uframe = start % mod;
1411                         goto ready;
1412                 }
1413         }
1414
1415         /* no room in the schedule */
1416         ehci_dbg (ehci, "iso %ssched full %p (now %d max %d)\n",
1417                 list_empty (&stream->td_list) ? "" : "re",
1418                 urb, now, max);
1419         status = -ENOSPC;
1420
1421 fail:
1422         iso_sched_free (stream, sched);
1423         urb->hcpriv = NULL;
1424         return status;
1425
1426 ready:
1427         /* report high speed start in uframes; full speed, in frames */
1428         urb->start_frame = stream->next_uframe;
1429         if (!stream->highspeed)
1430                 urb->start_frame >>= 3;
1431         return 0;
1432 }
1433
1434 /*-------------------------------------------------------------------------*/
1435
1436 static inline void
1437 itd_init(struct ehci_hcd *ehci, struct ehci_iso_stream *stream,
1438                 struct ehci_itd *itd)
1439 {
1440         int i;
1441
1442         /* it's been recently zeroed */
1443         itd->hw_next = EHCI_LIST_END(ehci);
1444         itd->hw_bufp [0] = stream->buf0;
1445         itd->hw_bufp [1] = stream->buf1;
1446         itd->hw_bufp [2] = stream->buf2;
1447
1448         for (i = 0; i < 8; i++)
1449                 itd->index[i] = -1;
1450
1451         /* All other fields are filled when scheduling */
1452 }
1453
1454 static inline void
1455 itd_patch(
1456         struct ehci_hcd         *ehci,
1457         struct ehci_itd         *itd,
1458         struct ehci_iso_sched   *iso_sched,
1459         unsigned                index,
1460         u16                     uframe
1461 )
1462 {
1463         struct ehci_iso_packet  *uf = &iso_sched->packet [index];
1464         unsigned                pg = itd->pg;
1465
1466         // BUG_ON (pg == 6 && uf->cross);
1467
1468         uframe &= 0x07;
1469         itd->index [uframe] = index;
1470
1471         itd->hw_transaction[uframe] = uf->transaction;
1472         itd->hw_transaction[uframe] |= cpu_to_hc32(ehci, pg << 12);
1473         itd->hw_bufp[pg] |= cpu_to_hc32(ehci, uf->bufp & ~(u32)0);
1474         itd->hw_bufp_hi[pg] |= cpu_to_hc32(ehci, (u32)(uf->bufp >> 32));
1475
1476         /* iso_frame_desc[].offset must be strictly increasing */
1477         if (unlikely (uf->cross)) {
1478                 u64     bufp = uf->bufp + 4096;
1479
1480                 itd->pg = ++pg;
1481                 itd->hw_bufp[pg] |= cpu_to_hc32(ehci, bufp & ~(u32)0);
1482                 itd->hw_bufp_hi[pg] |= cpu_to_hc32(ehci, (u32)(bufp >> 32));
1483         }
1484 }
1485
1486 static inline void
1487 itd_link (struct ehci_hcd *ehci, unsigned frame, struct ehci_itd *itd)
1488 {
1489         /* always prepend ITD/SITD ... only QH tree is order-sensitive */
1490         itd->itd_next = ehci->pshadow [frame];
1491         itd->hw_next = ehci->periodic [frame];
1492         ehci->pshadow [frame].itd = itd;
1493         itd->frame = frame;
1494         wmb ();
1495         ehci->periodic[frame] = cpu_to_hc32(ehci, itd->itd_dma | Q_TYPE_ITD);
1496 }
1497
1498 /* fit urb's itds into the selected schedule slot; activate as needed */
1499 static int
1500 itd_link_urb (
1501         struct ehci_hcd         *ehci,
1502         struct urb              *urb,
1503         unsigned                mod,
1504         struct ehci_iso_stream  *stream
1505 )
1506 {
1507         int                     packet;
1508         unsigned                next_uframe, uframe, frame;
1509         struct ehci_iso_sched   *iso_sched = urb->hcpriv;
1510         struct ehci_itd         *itd;
1511
1512         next_uframe = stream->next_uframe % mod;
1513
1514         if (unlikely (list_empty(&stream->td_list))) {
1515                 ehci_to_hcd(ehci)->self.bandwidth_allocated
1516                                 += stream->bandwidth;
1517                 ehci_vdbg (ehci,
1518                         "schedule devp %s ep%d%s-iso period %d start %d.%d\n",
1519                         urb->dev->devpath, stream->bEndpointAddress & 0x0f,
1520                         (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out",
1521                         urb->interval,
1522                         next_uframe >> 3, next_uframe & 0x7);
1523                 stream->start = jiffies;
1524         }
1525         ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs++;
1526
1527         /* fill iTDs uframe by uframe */
1528         for (packet = 0, itd = NULL; packet < urb->number_of_packets; ) {
1529                 if (itd == NULL) {
1530                         /* ASSERT:  we have all necessary itds */
1531                         // BUG_ON (list_empty (&iso_sched->td_list));
1532
1533                         /* ASSERT:  no itds for this endpoint in this uframe */
1534
1535                         itd = list_entry (iso_sched->td_list.next,
1536                                         struct ehci_itd, itd_list);
1537                         list_move_tail (&itd->itd_list, &stream->td_list);
1538                         itd->stream = iso_stream_get (stream);
1539                         itd->urb = usb_get_urb (urb);
1540                         itd_init (ehci, stream, itd);
1541                 }
1542
1543                 uframe = next_uframe & 0x07;
1544                 frame = next_uframe >> 3;
1545
1546                 itd_patch(ehci, itd, iso_sched, packet, uframe);
1547
1548                 next_uframe += stream->interval;
1549                 stream->depth += stream->interval;
1550                 next_uframe %= mod;
1551                 packet++;
1552
1553                 /* link completed itds into the schedule */
1554                 if (((next_uframe >> 3) != frame)
1555                                 || packet == urb->number_of_packets) {
1556                         itd_link (ehci, frame % ehci->periodic_size, itd);
1557                         itd = NULL;
1558                 }
1559         }
1560         stream->next_uframe = next_uframe;
1561
1562         /* don't need that schedule data any more */
1563         iso_sched_free (stream, iso_sched);
1564         urb->hcpriv = NULL;
1565
1566         timer_action (ehci, TIMER_IO_WATCHDOG);
1567         return enable_periodic(ehci);
1568 }
1569
1570 #define ISO_ERRS (EHCI_ISOC_BUF_ERR | EHCI_ISOC_BABBLE | EHCI_ISOC_XACTERR)
1571
1572 /* Process and recycle a completed ITD.  Return true iff its urb completed,
1573  * and hence its completion callback probably added things to the hardware
1574  * schedule.
1575  *
1576  * Note that we carefully avoid recycling this descriptor until after any
1577  * completion callback runs, so that it won't be reused quickly.  That is,
1578  * assuming (a) no more than two urbs per frame on this endpoint, and also
1579  * (b) only this endpoint's completions submit URBs.  It seems some silicon
1580  * corrupts things if you reuse completed descriptors very quickly...
1581  */
1582 static unsigned
1583 itd_complete (
1584         struct ehci_hcd *ehci,
1585         struct ehci_itd *itd
1586 ) {
1587         struct urb                              *urb = itd->urb;
1588         struct usb_iso_packet_descriptor        *desc;
1589         u32                                     t;
1590         unsigned                                uframe;
1591         int                                     urb_index = -1;
1592         struct ehci_iso_stream                  *stream = itd->stream;
1593         struct usb_device                       *dev;
1594         unsigned                                retval = false;
1595
1596         /* for each uframe with a packet */
1597         for (uframe = 0; uframe < 8; uframe++) {
1598                 if (likely (itd->index[uframe] == -1))
1599                         continue;
1600                 urb_index = itd->index[uframe];
1601                 desc = &urb->iso_frame_desc [urb_index];
1602
1603                 t = hc32_to_cpup(ehci, &itd->hw_transaction [uframe]);
1604                 itd->hw_transaction [uframe] = 0;
1605                 stream->depth -= stream->interval;
1606
1607                 /* report transfer status */
1608                 if (unlikely (t & ISO_ERRS)) {
1609                         urb->error_count++;
1610                         if (t & EHCI_ISOC_BUF_ERR)
1611                                 desc->status = usb_pipein (urb->pipe)
1612                                         ? -ENOSR  /* hc couldn't read */
1613                                         : -ECOMM; /* hc couldn't write */
1614                         else if (t & EHCI_ISOC_BABBLE)
1615                                 desc->status = -EOVERFLOW;
1616                         else /* (t & EHCI_ISOC_XACTERR) */
1617                                 desc->status = -EPROTO;
1618
1619                         /* HC need not update length with this error */
1620                         if (!(t & EHCI_ISOC_BABBLE))
1621                                 desc->actual_length = EHCI_ITD_LENGTH (t);
1622                 } else if (likely ((t & EHCI_ISOC_ACTIVE) == 0)) {
1623                         desc->status = 0;
1624                         desc->actual_length = EHCI_ITD_LENGTH (t);
1625                 } else {
1626                         /* URB was too late */
1627                         desc->status = -EXDEV;
1628                 }
1629         }
1630
1631         /* handle completion now? */
1632         if (likely ((urb_index + 1) != urb->number_of_packets))
1633                 goto done;
1634
1635         /* ASSERT: it's really the last itd for this urb
1636         list_for_each_entry (itd, &stream->td_list, itd_list)
1637                 BUG_ON (itd->urb == urb);
1638          */
1639
1640         /* give urb back to the driver; completion often (re)submits */
1641         dev = urb->dev;
1642         ehci_urb_done(ehci, urb, 0);
1643         retval = true;
1644         urb = NULL;
1645         (void) disable_periodic(ehci);
1646         ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs--;
1647
1648         if (unlikely (list_empty (&stream->td_list))) {
1649                 ehci_to_hcd(ehci)->self.bandwidth_allocated
1650                                 -= stream->bandwidth;
1651                 ehci_vdbg (ehci,
1652                         "deschedule devp %s ep%d%s-iso\n",
1653                         dev->devpath, stream->bEndpointAddress & 0x0f,
1654                         (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out");
1655         }
1656         iso_stream_put (ehci, stream);
1657
1658 done:
1659         usb_put_urb(urb);
1660         itd->urb = NULL;
1661         if (ehci->clock_frame != itd->frame || itd->index[7] != -1) {
1662                 /* OK to recycle this ITD now. */
1663                 itd->stream = NULL;
1664                 list_move(&itd->itd_list, &stream->free_list);
1665                 iso_stream_put(ehci, stream);
1666         } else {
1667                 /* HW might remember this ITD, so we can't recycle it yet.
1668                  * Move it to a safe place until a new frame starts.
1669                  */
1670                 list_move(&itd->itd_list, &ehci->cached_itd_list);
1671                 if (stream->refcount == 2) {
1672                         /* If iso_stream_put() were called here, stream
1673                          * would be freed.  Instead, just prevent reuse.
1674                          */
1675                         stream->ep->hcpriv = NULL;
1676                         stream->ep = NULL;
1677                 }
1678         }
1679         return retval;
1680 }
1681
1682 /*-------------------------------------------------------------------------*/
1683
1684 static int itd_submit (struct ehci_hcd *ehci, struct urb *urb,
1685         gfp_t mem_flags)
1686 {
1687         int                     status = -EINVAL;
1688         unsigned long           flags;
1689         struct ehci_iso_stream  *stream;
1690
1691         /* Get iso_stream head */
1692         stream = iso_stream_find (ehci, urb);
1693         if (unlikely (stream == NULL)) {
1694                 ehci_dbg (ehci, "can't get iso stream\n");
1695                 return -ENOMEM;
1696         }
1697         if (unlikely (urb->interval != stream->interval)) {
1698                 ehci_dbg (ehci, "can't change iso interval %d --> %d\n",
1699                         stream->interval, urb->interval);
1700                 goto done;
1701         }
1702
1703 #ifdef EHCI_URB_TRACE
1704         ehci_dbg (ehci,
1705                 "%s %s urb %p ep%d%s len %d, %d pkts %d uframes [%p]\n",
1706                 __func__, urb->dev->devpath, urb,
1707                 usb_pipeendpoint (urb->pipe),
1708                 usb_pipein (urb->pipe) ? "in" : "out",
1709                 urb->transfer_buffer_length,
1710                 urb->number_of_packets, urb->interval,
1711                 stream);
1712 #endif
1713
1714         /* allocate ITDs w/o locking anything */
1715         status = itd_urb_transaction (stream, ehci, urb, mem_flags);
1716         if (unlikely (status < 0)) {
1717                 ehci_dbg (ehci, "can't init itds\n");
1718                 goto done;
1719         }
1720
1721         /* schedule ... need to lock */
1722         spin_lock_irqsave (&ehci->lock, flags);
1723         if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE,
1724                                &ehci_to_hcd(ehci)->flags))) {
1725                 status = -ESHUTDOWN;
1726                 goto done_not_linked;
1727         }
1728         status = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
1729         if (unlikely(status))
1730                 goto done_not_linked;
1731         status = iso_stream_schedule(ehci, urb, stream);
1732         if (likely (status == 0))
1733                 itd_link_urb (ehci, urb, ehci->periodic_size << 3, stream);
1734         else
1735                 usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
1736 done_not_linked:
1737         spin_unlock_irqrestore (&ehci->lock, flags);
1738
1739 done:
1740         if (unlikely (status < 0))
1741                 iso_stream_put (ehci, stream);
1742         return status;
1743 }
1744
1745 /*-------------------------------------------------------------------------*/
1746
1747 /*
1748  * "Split ISO TDs" ... used for USB 1.1 devices going through the
1749  * TTs in USB 2.0 hubs.  These need microframe scheduling.
1750  */
1751
1752 static inline void
1753 sitd_sched_init(
1754         struct ehci_hcd         *ehci,
1755         struct ehci_iso_sched   *iso_sched,
1756         struct ehci_iso_stream  *stream,
1757         struct urb              *urb
1758 )
1759 {
1760         unsigned        i;
1761         dma_addr_t      dma = urb->transfer_dma;
1762
1763         /* how many frames are needed for these transfers */
1764         iso_sched->span = urb->number_of_packets * stream->interval;
1765
1766         /* figure out per-frame sitd fields that we'll need later
1767          * when we fit new sitds into the schedule.
1768          */
1769         for (i = 0; i < urb->number_of_packets; i++) {
1770                 struct ehci_iso_packet  *packet = &iso_sched->packet [i];
1771                 unsigned                length;
1772                 dma_addr_t              buf;
1773                 u32                     trans;
1774
1775                 length = urb->iso_frame_desc [i].length & 0x03ff;
1776                 buf = dma + urb->iso_frame_desc [i].offset;
1777
1778                 trans = SITD_STS_ACTIVE;
1779                 if (((i + 1) == urb->number_of_packets)
1780                                 && !(urb->transfer_flags & URB_NO_INTERRUPT))
1781                         trans |= SITD_IOC;
1782                 trans |= length << 16;
1783                 packet->transaction = cpu_to_hc32(ehci, trans);
1784
1785                 /* might need to cross a buffer page within a td */
1786                 packet->bufp = buf;
1787                 packet->buf1 = (buf + length) & ~0x0fff;
1788                 if (packet->buf1 != (buf & ~(u64)0x0fff))
1789                         packet->cross = 1;
1790
1791                 /* OUT uses multiple start-splits */
1792                 if (stream->bEndpointAddress & USB_DIR_IN)
1793                         continue;
1794                 length = (length + 187) / 188;
1795                 if (length > 1) /* BEGIN vs ALL */
1796                         length |= 1 << 3;
1797                 packet->buf1 |= length;
1798         }
1799 }
1800
1801 static int
1802 sitd_urb_transaction (
1803         struct ehci_iso_stream  *stream,
1804         struct ehci_hcd         *ehci,
1805         struct urb              *urb,
1806         gfp_t                   mem_flags
1807 )
1808 {
1809         struct ehci_sitd        *sitd;
1810         dma_addr_t              sitd_dma;
1811         int                     i;
1812         struct ehci_iso_sched   *iso_sched;
1813         unsigned long           flags;
1814
1815         iso_sched = iso_sched_alloc (urb->number_of_packets, mem_flags);
1816         if (iso_sched == NULL)
1817                 return -ENOMEM;
1818
1819         sitd_sched_init(ehci, iso_sched, stream, urb);
1820
1821         /* allocate/init sITDs */
1822         spin_lock_irqsave (&ehci->lock, flags);
1823         for (i = 0; i < urb->number_of_packets; i++) {
1824
1825                 /* NOTE:  for now, we don't try to handle wraparound cases
1826                  * for IN (using sitd->hw_backpointer, like a FSTN), which
1827                  * means we never need two sitds for full speed packets.
1828                  */
1829
1830                 /* free_list.next might be cache-hot ... but maybe
1831                  * the HC caches it too. avoid that issue for now.
1832                  */
1833
1834                 /* prefer previously-allocated sitds */
1835                 if (!list_empty(&stream->free_list)) {
1836                         sitd = list_entry (stream->free_list.prev,
1837                                          struct ehci_sitd, sitd_list);
1838                         list_del (&sitd->sitd_list);
1839                         sitd_dma = sitd->sitd_dma;
1840                 } else {
1841                         spin_unlock_irqrestore (&ehci->lock, flags);
1842                         sitd = dma_pool_alloc (ehci->sitd_pool, mem_flags,
1843                                         &sitd_dma);
1844                         spin_lock_irqsave (&ehci->lock, flags);
1845                         if (!sitd) {
1846                                 iso_sched_free(stream, iso_sched);
1847                                 spin_unlock_irqrestore(&ehci->lock, flags);
1848                                 return -ENOMEM;
1849                         }
1850                 }
1851
1852                 memset (sitd, 0, sizeof *sitd);
1853                 sitd->sitd_dma = sitd_dma;
1854                 list_add (&sitd->sitd_list, &iso_sched->td_list);
1855         }
1856
1857         /* temporarily store schedule info in hcpriv */
1858         urb->hcpriv = iso_sched;
1859         urb->error_count = 0;
1860
1861         spin_unlock_irqrestore (&ehci->lock, flags);
1862         return 0;
1863 }
1864
1865 /*-------------------------------------------------------------------------*/
1866
1867 static inline void
1868 sitd_patch(
1869         struct ehci_hcd         *ehci,
1870         struct ehci_iso_stream  *stream,
1871         struct ehci_sitd        *sitd,
1872         struct ehci_iso_sched   *iso_sched,
1873         unsigned                index
1874 )
1875 {
1876         struct ehci_iso_packet  *uf = &iso_sched->packet [index];
1877         u64                     bufp = uf->bufp;
1878
1879         sitd->hw_next = EHCI_LIST_END(ehci);
1880         sitd->hw_fullspeed_ep = stream->address;
1881         sitd->hw_uframe = stream->splits;
1882         sitd->hw_results = uf->transaction;
1883         sitd->hw_backpointer = EHCI_LIST_END(ehci);
1884
1885         bufp = uf->bufp;
1886         sitd->hw_buf[0] = cpu_to_hc32(ehci, bufp);
1887         sitd->hw_buf_hi[0] = cpu_to_hc32(ehci, bufp >> 32);
1888
1889         sitd->hw_buf[1] = cpu_to_hc32(ehci, uf->buf1);
1890         if (uf->cross)
1891                 bufp += 4096;
1892         sitd->hw_buf_hi[1] = cpu_to_hc32(ehci, bufp >> 32);
1893         sitd->index = index;
1894 }
1895
1896 static inline void
1897 sitd_link (struct ehci_hcd *ehci, unsigned frame, struct ehci_sitd *sitd)
1898 {
1899         /* note: sitd ordering could matter (CSPLIT then SSPLIT) */
1900         sitd->sitd_next = ehci->pshadow [frame];
1901         sitd->hw_next = ehci->periodic [frame];
1902         ehci->pshadow [frame].sitd = sitd;
1903         sitd->frame = frame;
1904         wmb ();
1905         ehci->periodic[frame] = cpu_to_hc32(ehci, sitd->sitd_dma | Q_TYPE_SITD);
1906 }
1907
1908 /* fit urb's sitds into the selected schedule slot; activate as needed */
1909 static int
1910 sitd_link_urb (
1911         struct ehci_hcd         *ehci,
1912         struct urb              *urb,
1913         unsigned                mod,
1914         struct ehci_iso_stream  *stream
1915 )
1916 {
1917         int                     packet;
1918         unsigned                next_uframe;
1919         struct ehci_iso_sched   *sched = urb->hcpriv;
1920         struct ehci_sitd        *sitd;
1921
1922         next_uframe = stream->next_uframe;
1923
1924         if (list_empty(&stream->td_list)) {
1925                 /* usbfs ignores TT bandwidth */
1926                 ehci_to_hcd(ehci)->self.bandwidth_allocated
1927                                 += stream->bandwidth;
1928                 ehci_vdbg (ehci,
1929                         "sched devp %s ep%d%s-iso [%d] %dms/%04x\n",
1930                         urb->dev->devpath, stream->bEndpointAddress & 0x0f,
1931                         (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out",
1932                         (next_uframe >> 3) % ehci->periodic_size,
1933                         stream->interval, hc32_to_cpu(ehci, stream->splits));
1934                 stream->start = jiffies;
1935         }
1936         ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs++;
1937
1938         /* fill sITDs frame by frame */
1939         for (packet = 0, sitd = NULL;
1940                         packet < urb->number_of_packets;
1941                         packet++) {
1942
1943                 /* ASSERT:  we have all necessary sitds */
1944                 BUG_ON (list_empty (&sched->td_list));
1945
1946                 /* ASSERT:  no itds for this endpoint in this frame */
1947
1948                 sitd = list_entry (sched->td_list.next,
1949                                 struct ehci_sitd, sitd_list);
1950                 list_move_tail (&sitd->sitd_list, &stream->td_list);
1951                 sitd->stream = iso_stream_get (stream);
1952                 sitd->urb = usb_get_urb (urb);
1953
1954                 sitd_patch(ehci, stream, sitd, sched, packet);
1955                 sitd_link (ehci, (next_uframe >> 3) % ehci->periodic_size,
1956                                 sitd);
1957
1958                 next_uframe += stream->interval << 3;
1959                 stream->depth += stream->interval << 3;
1960         }
1961         stream->next_uframe = next_uframe % mod;
1962
1963         /* don't need that schedule data any more */
1964         iso_sched_free (stream, sched);
1965         urb->hcpriv = NULL;
1966
1967         timer_action (ehci, TIMER_IO_WATCHDOG);
1968         return enable_periodic(ehci);
1969 }
1970
1971 /*-------------------------------------------------------------------------*/
1972
1973 #define SITD_ERRS (SITD_STS_ERR | SITD_STS_DBE | SITD_STS_BABBLE \
1974                                 | SITD_STS_XACT | SITD_STS_MMF)
1975
1976 /* Process and recycle a completed SITD.  Return true iff its urb completed,
1977  * and hence its completion callback probably added things to the hardware
1978  * schedule.
1979  *
1980  * Note that we carefully avoid recycling this descriptor until after any
1981  * completion callback runs, so that it won't be reused quickly.  That is,
1982  * assuming (a) no more than two urbs per frame on this endpoint, and also
1983  * (b) only this endpoint's completions submit URBs.  It seems some silicon
1984  * corrupts things if you reuse completed descriptors very quickly...
1985  */
1986 static unsigned
1987 sitd_complete (
1988         struct ehci_hcd         *ehci,
1989         struct ehci_sitd        *sitd
1990 ) {
1991         struct urb                              *urb = sitd->urb;
1992         struct usb_iso_packet_descriptor        *desc;
1993         u32                                     t;
1994         int                                     urb_index = -1;
1995         struct ehci_iso_stream                  *stream = sitd->stream;
1996         struct usb_device                       *dev;
1997         unsigned                                retval = false;
1998
1999         urb_index = sitd->index;
2000         desc = &urb->iso_frame_desc [urb_index];
2001         t = hc32_to_cpup(ehci, &sitd->hw_results);
2002
2003         /* report transfer status */
2004         if (t & SITD_ERRS) {
2005                 urb->error_count++;
2006                 if (t & SITD_STS_DBE)
2007                         desc->status = usb_pipein (urb->pipe)
2008                                 ? -ENOSR  /* hc couldn't read */
2009                                 : -ECOMM; /* hc couldn't write */
2010                 else if (t & SITD_STS_BABBLE)
2011                         desc->status = -EOVERFLOW;
2012                 else /* XACT, MMF, etc */
2013                         desc->status = -EPROTO;
2014         } else {
2015                 desc->status = 0;
2016                 desc->actual_length = desc->length - SITD_LENGTH (t);
2017         }
2018         stream->depth -= stream->interval << 3;
2019
2020         /* handle completion now? */
2021         if ((urb_index + 1) != urb->number_of_packets)
2022                 goto done;
2023
2024         /* ASSERT: it's really the last sitd for this urb
2025         list_for_each_entry (sitd, &stream->td_list, sitd_list)
2026                 BUG_ON (sitd->urb == urb);
2027          */
2028
2029         /* give urb back to the driver; completion often (re)submits */
2030         dev = urb->dev;
2031         ehci_urb_done(ehci, urb, 0);
2032         retval = true;
2033         urb = NULL;
2034         (void) disable_periodic(ehci);
2035         ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs--;
2036
2037         if (list_empty (&stream->td_list)) {
2038                 ehci_to_hcd(ehci)->self.bandwidth_allocated
2039                                 -= stream->bandwidth;
2040                 ehci_vdbg (ehci,
2041                         "deschedule devp %s ep%d%s-iso\n",
2042                         dev->devpath, stream->bEndpointAddress & 0x0f,
2043                         (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out");
2044         }
2045         iso_stream_put (ehci, stream);
2046         /* OK to recycle this SITD now that its completion callback ran. */
2047 done:
2048         usb_put_urb(urb);
2049         sitd->urb = NULL;
2050         sitd->stream = NULL;
2051         list_move(&sitd->sitd_list, &stream->free_list);
2052         iso_stream_put(ehci, stream);
2053
2054         return retval;
2055 }
2056
2057
2058 static int sitd_submit (struct ehci_hcd *ehci, struct urb *urb,
2059         gfp_t mem_flags)
2060 {
2061         int                     status = -EINVAL;
2062         unsigned long           flags;
2063         struct ehci_iso_stream  *stream;
2064
2065         /* Get iso_stream head */
2066         stream = iso_stream_find (ehci, urb);
2067         if (stream == NULL) {
2068                 ehci_dbg (ehci, "can't get iso stream\n");
2069                 return -ENOMEM;
2070         }
2071         if (urb->interval != stream->interval) {
2072                 ehci_dbg (ehci, "can't change iso interval %d --> %d\n",
2073                         stream->interval, urb->interval);
2074                 goto done;
2075         }
2076
2077 #ifdef EHCI_URB_TRACE
2078         ehci_dbg (ehci,
2079                 "submit %p dev%s ep%d%s-iso len %d\n",
2080                 urb, urb->dev->devpath,
2081                 usb_pipeendpoint (urb->pipe),
2082                 usb_pipein (urb->pipe) ? "in" : "out",
2083                 urb->transfer_buffer_length);
2084 #endif
2085
2086         /* allocate SITDs */
2087         status = sitd_urb_transaction (stream, ehci, urb, mem_flags);
2088         if (status < 0) {
2089                 ehci_dbg (ehci, "can't init sitds\n");
2090                 goto done;
2091         }
2092
2093         /* schedule ... need to lock */
2094         spin_lock_irqsave (&ehci->lock, flags);
2095         if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE,
2096                                &ehci_to_hcd(ehci)->flags))) {
2097                 status = -ESHUTDOWN;
2098                 goto done_not_linked;
2099         }
2100         status = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
2101         if (unlikely(status))
2102                 goto done_not_linked;
2103         status = iso_stream_schedule(ehci, urb, stream);
2104         if (status == 0)
2105                 sitd_link_urb (ehci, urb, ehci->periodic_size << 3, stream);
2106         else
2107                 usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
2108 done_not_linked:
2109         spin_unlock_irqrestore (&ehci->lock, flags);
2110
2111 done:
2112         if (status < 0)
2113                 iso_stream_put (ehci, stream);
2114         return status;
2115 }
2116
2117 /*-------------------------------------------------------------------------*/
2118
2119 static void free_cached_itd_list(struct ehci_hcd *ehci)
2120 {
2121         struct ehci_itd *itd, *n;
2122
2123         list_for_each_entry_safe(itd, n, &ehci->cached_itd_list, itd_list) {
2124                 struct ehci_iso_stream  *stream = itd->stream;
2125                 itd->stream = NULL;
2126                 list_move(&itd->itd_list, &stream->free_list);
2127                 iso_stream_put(ehci, stream);
2128         }
2129 }
2130
2131 /*-------------------------------------------------------------------------*/
2132
2133 static void
2134 scan_periodic (struct ehci_hcd *ehci)
2135 {
2136         unsigned        now_uframe, frame, clock, clock_frame, mod;
2137         unsigned        modified;
2138
2139         mod = ehci->periodic_size << 3;
2140
2141         /*
2142          * When running, scan from last scan point up to "now"
2143          * else clean up by scanning everything that's left.
2144          * Touches as few pages as possible:  cache-friendly.
2145          */
2146         now_uframe = ehci->next_uframe;
2147         if (HC_IS_RUNNING(ehci_to_hcd(ehci)->state)) {
2148                 clock = ehci_readl(ehci, &ehci->regs->frame_index);
2149                 clock_frame = (clock >> 3) % ehci->periodic_size;
2150         } else  {
2151                 clock = now_uframe + mod - 1;
2152                 clock_frame = -1;
2153         }
2154         if (ehci->clock_frame != clock_frame) {
2155                 free_cached_itd_list(ehci);
2156                 ehci->clock_frame = clock_frame;
2157         }
2158         clock %= mod;
2159         clock_frame = clock >> 3;
2160
2161         for (;;) {
2162                 union ehci_shadow       q, *q_p;
2163                 __hc32                  type, *hw_p;
2164                 unsigned                incomplete = false;
2165
2166                 frame = now_uframe >> 3;
2167
2168 restart:
2169                 /* scan each element in frame's queue for completions */
2170                 q_p = &ehci->pshadow [frame];
2171                 hw_p = &ehci->periodic [frame];
2172                 q.ptr = q_p->ptr;
2173                 type = Q_NEXT_TYPE(ehci, *hw_p);
2174                 modified = 0;
2175
2176                 while (q.ptr != NULL) {
2177                         unsigned                uf;
2178                         union ehci_shadow       temp;
2179                         int                     live;
2180
2181                         live = HC_IS_RUNNING (ehci_to_hcd(ehci)->state);
2182                         switch (hc32_to_cpu(ehci, type)) {
2183                         case Q_TYPE_QH:
2184                                 /* handle any completions */
2185                                 temp.qh = qh_get (q.qh);
2186                                 type = Q_NEXT_TYPE(ehci, q.qh->hw_next);
2187                                 q = q.qh->qh_next;
2188                                 modified = qh_completions (ehci, temp.qh);
2189                                 if (unlikely (list_empty (&temp.qh->qtd_list)))
2190                                         intr_deschedule (ehci, temp.qh);
2191                                 qh_put (temp.qh);
2192                                 break;
2193                         case Q_TYPE_FSTN:
2194                                 /* for "save place" FSTNs, look at QH entries
2195                                  * in the previous frame for completions.
2196                                  */
2197                                 if (q.fstn->hw_prev != EHCI_LIST_END(ehci)) {
2198                                         dbg ("ignoring completions from FSTNs");
2199                                 }
2200                                 type = Q_NEXT_TYPE(ehci, q.fstn->hw_next);
2201                                 q = q.fstn->fstn_next;
2202                                 break;
2203                         case Q_TYPE_ITD:
2204                                 /* If this ITD is still active, leave it for
2205                                  * later processing ... check the next entry.
2206                                  * No need to check for activity unless the
2207                                  * frame is current.
2208                                  */
2209                                 if (frame == clock_frame && live) {
2210                                         rmb();
2211                                         for (uf = 0; uf < 8; uf++) {
2212                                                 if (q.itd->hw_transaction[uf] &
2213                                                             ITD_ACTIVE(ehci))
2214                                                         break;
2215                                         }
2216                                         if (uf < 8) {
2217                                                 incomplete = true;
2218                                                 q_p = &q.itd->itd_next;
2219                                                 hw_p = &q.itd->hw_next;
2220                                                 type = Q_NEXT_TYPE(ehci,
2221                                                         q.itd->hw_next);
2222                                                 q = *q_p;
2223                                                 break;
2224                                         }
2225                                 }
2226
2227                                 /* Take finished ITDs out of the schedule
2228                                  * and process them:  recycle, maybe report
2229                                  * URB completion.  HC won't cache the
2230                                  * pointer for much longer, if at all.
2231                                  */
2232                                 *q_p = q.itd->itd_next;
2233                                 *hw_p = q.itd->hw_next;
2234                                 type = Q_NEXT_TYPE(ehci, q.itd->hw_next);
2235                                 wmb();
2236                                 modified = itd_complete (ehci, q.itd);
2237                                 q = *q_p;
2238                                 break;
2239                         case Q_TYPE_SITD:
2240                                 /* If this SITD is still active, leave it for
2241                                  * later processing ... check the next entry.
2242                                  * No need to check for activity unless the
2243                                  * frame is current.
2244                                  */
2245                                 if (frame == clock_frame && live &&
2246                                                 (q.sitd->hw_results &
2247                                                         SITD_ACTIVE(ehci))) {
2248                                         incomplete = true;
2249                                         q_p = &q.sitd->sitd_next;
2250                                         hw_p = &q.sitd->hw_next;
2251                                         type = Q_NEXT_TYPE(ehci,
2252                                                         q.sitd->hw_next);
2253                                         q = *q_p;
2254                                         break;
2255                                 }
2256
2257                                 /* Take finished SITDs out of the schedule
2258                                  * and process them:  recycle, maybe report
2259                                  * URB completion.
2260                                  */
2261                                 *q_p = q.sitd->sitd_next;
2262                                 *hw_p = q.sitd->hw_next;
2263                                 type = Q_NEXT_TYPE(ehci, q.sitd->hw_next);
2264                                 wmb();
2265                                 modified = sitd_complete (ehci, q.sitd);
2266                                 q = *q_p;
2267                                 break;
2268                         default:
2269                                 dbg ("corrupt type %d frame %d shadow %p",
2270                                         type, frame, q.ptr);
2271                                 // BUG ();
2272                                 q.ptr = NULL;
2273                         }
2274
2275                         /* assume completion callbacks modify the queue */
2276                         if (unlikely (modified)) {
2277                                 if (likely(ehci->periodic_sched > 0))
2278                                         goto restart;
2279                                 /* short-circuit this scan */
2280                                 now_uframe = clock;
2281                                 break;
2282                         }
2283                 }
2284
2285                 /* If we can tell we caught up to the hardware, stop now.
2286                  * We can't advance our scan without collecting the ISO
2287                  * transfers that are still pending in this frame.
2288                  */
2289                 if (incomplete && HC_IS_RUNNING(ehci_to_hcd(ehci)->state)) {
2290                         ehci->next_uframe = now_uframe;
2291                         break;
2292                 }
2293
2294                 // FIXME:  this assumes we won't get lapped when
2295                 // latencies climb; that should be rare, but...
2296                 // detect it, and just go all the way around.
2297                 // FLR might help detect this case, so long as latencies
2298                 // don't exceed periodic_size msec (default 1.024 sec).
2299
2300                 // FIXME:  likewise assumes HC doesn't halt mid-scan
2301
2302                 if (now_uframe == clock) {
2303                         unsigned        now;
2304
2305                         if (!HC_IS_RUNNING (ehci_to_hcd(ehci)->state)
2306                                         || ehci->periodic_sched == 0)
2307                                 break;
2308                         ehci->next_uframe = now_uframe;
2309                         now = ehci_readl(ehci, &ehci->regs->frame_index) % mod;
2310                         if (now_uframe == now)
2311                                 break;
2312
2313                         /* rescan the rest of this frame, then ... */
2314                         clock = now;
2315                         clock_frame = clock >> 3;
2316                         if (ehci->clock_frame != clock_frame) {
2317                                 free_cached_itd_list(ehci);
2318                                 ehci->clock_frame = clock_frame;
2319                         }
2320                 } else {
2321                         now_uframe++;
2322                         now_uframe %= mod;
2323                 }
2324         }
2325 }