Merge branch 'agp-patches' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied...
[linux-2.6] / drivers / usb / host / ehci-q.c
1 /*
2  * Copyright (C) 2001-2004 by David Brownell
3  *
4  * This program is free software; you can redistribute it and/or modify it
5  * under the terms of the GNU General Public License as published by the
6  * Free Software Foundation; either version 2 of the License, or (at your
7  * option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful, but
10  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
11  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12  * for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software Foundation,
16  * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17  */
18
19 /* this file is part of ehci-hcd.c */
20
21 /*-------------------------------------------------------------------------*/
22
23 /*
24  * EHCI hardware queue manipulation ... the core.  QH/QTD manipulation.
25  *
26  * Control, bulk, and interrupt traffic all use "qh" lists.  They list "qtd"
27  * entries describing USB transactions, max 16-20kB/entry (with 4kB-aligned
28  * buffers needed for the larger number).  We use one QH per endpoint, queue
29  * multiple urbs (all three types) per endpoint.  URBs may need several qtds.
30  *
31  * ISO traffic uses "ISO TD" (itd, and sitd) records, and (along with
32  * interrupts) needs careful scheduling.  Performance improvements can be
33  * an ongoing challenge.  That's in "ehci-sched.c".
34  *
35  * USB 1.1 devices are handled (a) by "companion" OHCI or UHCI root hubs,
36  * or otherwise through transaction translators (TTs) in USB 2.0 hubs using
37  * (b) special fields in qh entries or (c) split iso entries.  TTs will
38  * buffer low/full speed data so the host collects it at high speed.
39  */
40
41 /*-------------------------------------------------------------------------*/
42
43 /* fill a qtd, returning how much of the buffer we were able to queue up */
44
45 static int
46 qtd_fill(struct ehci_hcd *ehci, struct ehci_qtd *qtd, dma_addr_t buf,
47                   size_t len, int token, int maxpacket)
48 {
49         int     i, count;
50         u64     addr = buf;
51
52         /* one buffer entry per 4K ... first might be short or unaligned */
53         qtd->hw_buf[0] = cpu_to_hc32(ehci, (u32)addr);
54         qtd->hw_buf_hi[0] = cpu_to_hc32(ehci, (u32)(addr >> 32));
55         count = 0x1000 - (buf & 0x0fff);        /* rest of that page */
56         if (likely (len < count))               /* ... iff needed */
57                 count = len;
58         else {
59                 buf +=  0x1000;
60                 buf &= ~0x0fff;
61
62                 /* per-qtd limit: from 16K to 20K (best alignment) */
63                 for (i = 1; count < len && i < 5; i++) {
64                         addr = buf;
65                         qtd->hw_buf[i] = cpu_to_hc32(ehci, (u32)addr);
66                         qtd->hw_buf_hi[i] = cpu_to_hc32(ehci,
67                                         (u32)(addr >> 32));
68                         buf += 0x1000;
69                         if ((count + 0x1000) < len)
70                                 count += 0x1000;
71                         else
72                                 count = len;
73                 }
74
75                 /* short packets may only terminate transfers */
76                 if (count != len)
77                         count -= (count % maxpacket);
78         }
79         qtd->hw_token = cpu_to_hc32(ehci, (count << 16) | token);
80         qtd->length = count;
81
82         return count;
83 }
84
85 /*-------------------------------------------------------------------------*/
86
87 static inline void
88 qh_update (struct ehci_hcd *ehci, struct ehci_qh *qh, struct ehci_qtd *qtd)
89 {
90         /* writes to an active overlay are unsafe */
91         BUG_ON(qh->qh_state != QH_STATE_IDLE);
92
93         qh->hw_qtd_next = QTD_NEXT(ehci, qtd->qtd_dma);
94         qh->hw_alt_next = EHCI_LIST_END(ehci);
95
96         /* Except for control endpoints, we make hardware maintain data
97          * toggle (like OHCI) ... here (re)initialize the toggle in the QH,
98          * and set the pseudo-toggle in udev. Only usb_clear_halt() will
99          * ever clear it.
100          */
101         if (!(qh->hw_info1 & cpu_to_hc32(ehci, 1 << 14))) {
102                 unsigned        is_out, epnum;
103
104                 is_out = !(qtd->hw_token & cpu_to_hc32(ehci, 1 << 8));
105                 epnum = (hc32_to_cpup(ehci, &qh->hw_info1) >> 8) & 0x0f;
106                 if (unlikely (!usb_gettoggle (qh->dev, epnum, is_out))) {
107                         qh->hw_token &= ~cpu_to_hc32(ehci, QTD_TOGGLE);
108                         usb_settoggle (qh->dev, epnum, is_out, 1);
109                 }
110         }
111
112         /* HC must see latest qtd and qh data before we clear ACTIVE+HALT */
113         wmb ();
114         qh->hw_token &= cpu_to_hc32(ehci, QTD_TOGGLE | QTD_STS_PING);
115 }
116
117 /* if it weren't for a common silicon quirk (writing the dummy into the qh
118  * overlay, so qh->hw_token wrongly becomes inactive/halted), only fault
119  * recovery (including urb dequeue) would need software changes to a QH...
120  */
121 static void
122 qh_refresh (struct ehci_hcd *ehci, struct ehci_qh *qh)
123 {
124         struct ehci_qtd *qtd;
125
126         if (list_empty (&qh->qtd_list))
127                 qtd = qh->dummy;
128         else {
129                 qtd = list_entry (qh->qtd_list.next,
130                                 struct ehci_qtd, qtd_list);
131                 /* first qtd may already be partially processed */
132                 if (cpu_to_hc32(ehci, qtd->qtd_dma) == qh->hw_current)
133                         qtd = NULL;
134         }
135
136         if (qtd)
137                 qh_update (ehci, qh, qtd);
138 }
139
140 /*-------------------------------------------------------------------------*/
141
142 static void qtd_copy_status (
143         struct ehci_hcd *ehci,
144         struct urb *urb,
145         size_t length,
146         u32 token
147 )
148 {
149         /* count IN/OUT bytes, not SETUP (even short packets) */
150         if (likely (QTD_PID (token) != 2))
151                 urb->actual_length += length - QTD_LENGTH (token);
152
153         /* don't modify error codes */
154         if (unlikely (urb->status != -EINPROGRESS))
155                 return;
156
157         /* force cleanup after short read; not always an error */
158         if (unlikely (IS_SHORT_READ (token)))
159                 urb->status = -EREMOTEIO;
160
161         /* serious "can't proceed" faults reported by the hardware */
162         if (token & QTD_STS_HALT) {
163                 if (token & QTD_STS_BABBLE) {
164                         /* FIXME "must" disable babbling device's port too */
165                         urb->status = -EOVERFLOW;
166                 } else if (token & QTD_STS_MMF) {
167                         /* fs/ls interrupt xfer missed the complete-split */
168                         urb->status = -EPROTO;
169                 } else if (token & QTD_STS_DBE) {
170                         urb->status = (QTD_PID (token) == 1) /* IN ? */
171                                 ? -ENOSR  /* hc couldn't read data */
172                                 : -ECOMM; /* hc couldn't write data */
173                 } else if (token & QTD_STS_XACT) {
174                         /* timeout, bad crc, wrong PID, etc; retried */
175                         if (QTD_CERR (token))
176                                 urb->status = -EPIPE;
177                         else {
178                                 ehci_dbg (ehci, "devpath %s ep%d%s 3strikes\n",
179                                         urb->dev->devpath,
180                                         usb_pipeendpoint (urb->pipe),
181                                         usb_pipein (urb->pipe) ? "in" : "out");
182                                 urb->status = -EPROTO;
183                         }
184                 /* CERR nonzero + no errors + halt --> stall */
185                 } else if (QTD_CERR (token))
186                         urb->status = -EPIPE;
187                 else    /* unknown */
188                         urb->status = -EPROTO;
189
190                 ehci_vdbg (ehci,
191                         "dev%d ep%d%s qtd token %08x --> status %d\n",
192                         usb_pipedevice (urb->pipe),
193                         usb_pipeendpoint (urb->pipe),
194                         usb_pipein (urb->pipe) ? "in" : "out",
195                         token, urb->status);
196
197                 /* if async CSPLIT failed, try cleaning out the TT buffer */
198                 if (urb->status != -EPIPE
199                                 && urb->dev->tt && !usb_pipeint (urb->pipe)
200                                 && ((token & QTD_STS_MMF) != 0
201                                         || QTD_CERR(token) == 0)
202                                 && (!ehci_is_TDI(ehci)
203                                         || urb->dev->tt->hub !=
204                                            ehci_to_hcd(ehci)->self.root_hub)) {
205 #ifdef DEBUG
206                         struct usb_device *tt = urb->dev->tt->hub;
207                         dev_dbg (&tt->dev,
208                                 "clear tt buffer port %d, a%d ep%d t%08x\n",
209                                 urb->dev->ttport, urb->dev->devnum,
210                                 usb_pipeendpoint (urb->pipe), token);
211 #endif /* DEBUG */
212                         usb_hub_tt_clear_buffer (urb->dev, urb->pipe);
213                 }
214         }
215 }
216
217 static void
218 ehci_urb_done (struct ehci_hcd *ehci, struct urb *urb)
219 __releases(ehci->lock)
220 __acquires(ehci->lock)
221 {
222         if (likely (urb->hcpriv != NULL)) {
223                 struct ehci_qh  *qh = (struct ehci_qh *) urb->hcpriv;
224
225                 /* S-mask in a QH means it's an interrupt urb */
226                 if ((qh->hw_info2 & cpu_to_hc32(ehci, QH_SMASK)) != 0) {
227
228                         /* ... update hc-wide periodic stats (for usbfs) */
229                         ehci_to_hcd(ehci)->self.bandwidth_int_reqs--;
230                 }
231                 qh_put (qh);
232         }
233
234         spin_lock (&urb->lock);
235         urb->hcpriv = NULL;
236         switch (urb->status) {
237         case -EINPROGRESS:              /* success */
238                 urb->status = 0;
239         default:                        /* fault */
240                 COUNT (ehci->stats.complete);
241                 break;
242         case -EREMOTEIO:                /* fault or normal */
243                 if (!(urb->transfer_flags & URB_SHORT_NOT_OK))
244                         urb->status = 0;
245                 COUNT (ehci->stats.complete);
246                 break;
247         case -ECONNRESET:               /* canceled */
248         case -ENOENT:
249                 COUNT (ehci->stats.unlink);
250                 break;
251         }
252         spin_unlock (&urb->lock);
253
254 #ifdef EHCI_URB_TRACE
255         ehci_dbg (ehci,
256                 "%s %s urb %p ep%d%s status %d len %d/%d\n",
257                 __FUNCTION__, urb->dev->devpath, urb,
258                 usb_pipeendpoint (urb->pipe),
259                 usb_pipein (urb->pipe) ? "in" : "out",
260                 urb->status,
261                 urb->actual_length, urb->transfer_buffer_length);
262 #endif
263
264         /* complete() can reenter this HCD */
265         spin_unlock (&ehci->lock);
266         usb_hcd_giveback_urb (ehci_to_hcd(ehci), urb);
267         spin_lock (&ehci->lock);
268 }
269
270 static void start_unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh);
271 static void unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh);
272
273 static void intr_deschedule (struct ehci_hcd *ehci, struct ehci_qh *qh);
274 static int qh_schedule (struct ehci_hcd *ehci, struct ehci_qh *qh);
275
276 /*
277  * Process and free completed qtds for a qh, returning URBs to drivers.
278  * Chases up to qh->hw_current.  Returns number of completions called,
279  * indicating how much "real" work we did.
280  */
281 static unsigned
282 qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
283 {
284         struct ehci_qtd         *last = NULL, *end = qh->dummy;
285         struct list_head        *entry, *tmp;
286         int                     stopped;
287         unsigned                count = 0;
288         int                     do_status = 0;
289         u8                      state;
290         u32                     halt = HALT_BIT(ehci);
291
292         if (unlikely (list_empty (&qh->qtd_list)))
293                 return count;
294
295         /* completions (or tasks on other cpus) must never clobber HALT
296          * till we've gone through and cleaned everything up, even when
297          * they add urbs to this qh's queue or mark them for unlinking.
298          *
299          * NOTE:  unlinking expects to be done in queue order.
300          */
301         state = qh->qh_state;
302         qh->qh_state = QH_STATE_COMPLETING;
303         stopped = (state == QH_STATE_IDLE);
304
305         /* remove de-activated QTDs from front of queue.
306          * after faults (including short reads), cleanup this urb
307          * then let the queue advance.
308          * if queue is stopped, handles unlinks.
309          */
310         list_for_each_safe (entry, tmp, &qh->qtd_list) {
311                 struct ehci_qtd *qtd;
312                 struct urb      *urb;
313                 u32             token = 0;
314
315                 qtd = list_entry (entry, struct ehci_qtd, qtd_list);
316                 urb = qtd->urb;
317
318                 /* clean up any state from previous QTD ...*/
319                 if (last) {
320                         if (likely (last->urb != urb)) {
321                                 ehci_urb_done (ehci, last->urb);
322                                 count++;
323                         }
324                         ehci_qtd_free (ehci, last);
325                         last = NULL;
326                 }
327
328                 /* ignore urbs submitted during completions we reported */
329                 if (qtd == end)
330                         break;
331
332                 /* hardware copies qtd out of qh overlay */
333                 rmb ();
334                 token = hc32_to_cpu(ehci, qtd->hw_token);
335
336                 /* always clean up qtds the hc de-activated */
337                 if ((token & QTD_STS_ACTIVE) == 0) {
338
339                         if ((token & QTD_STS_HALT) != 0) {
340                                 stopped = 1;
341
342                         /* magic dummy for some short reads; qh won't advance.
343                          * that silicon quirk can kick in with this dummy too.
344                          */
345                         } else if (IS_SHORT_READ (token)
346                                         && !(qtd->hw_alt_next
347                                                 & EHCI_LIST_END(ehci))) {
348                                 stopped = 1;
349                                 goto halt;
350                         }
351
352                 /* stop scanning when we reach qtds the hc is using */
353                 } else if (likely (!stopped
354                                 && HC_IS_RUNNING (ehci_to_hcd(ehci)->state))) {
355                         break;
356
357                 } else {
358                         stopped = 1;
359
360                         if (unlikely (!HC_IS_RUNNING (ehci_to_hcd(ehci)->state)))
361                                 urb->status = -ESHUTDOWN;
362
363                         /* ignore active urbs unless some previous qtd
364                          * for the urb faulted (including short read) or
365                          * its urb was canceled.  we may patch qh or qtds.
366                          */
367                         if (likely (urb->status == -EINPROGRESS))
368                                 continue;
369
370                         /* issue status after short control reads */
371                         if (unlikely (do_status != 0)
372                                         && QTD_PID (token) == 0 /* OUT */) {
373                                 do_status = 0;
374                                 continue;
375                         }
376
377                         /* token in overlay may be most current */
378                         if (state == QH_STATE_IDLE
379                                         && cpu_to_hc32(ehci, qtd->qtd_dma)
380                                                 == qh->hw_current)
381                                 token = hc32_to_cpu(ehci, qh->hw_token);
382
383                         /* force halt for unlinked or blocked qh, so we'll
384                          * patch the qh later and so that completions can't
385                          * activate it while we "know" it's stopped.
386                          */
387                         if ((halt & qh->hw_token) == 0) {
388 halt:
389                                 qh->hw_token |= halt;
390                                 wmb ();
391                         }
392                 }
393
394                 /* remove it from the queue */
395                 spin_lock (&urb->lock);
396                 qtd_copy_status (ehci, urb, qtd->length, token);
397                 do_status = (urb->status == -EREMOTEIO)
398                                 && usb_pipecontrol (urb->pipe);
399                 spin_unlock (&urb->lock);
400
401                 if (stopped && qtd->qtd_list.prev != &qh->qtd_list) {
402                         last = list_entry (qtd->qtd_list.prev,
403                                         struct ehci_qtd, qtd_list);
404                         last->hw_next = qtd->hw_next;
405                 }
406                 list_del (&qtd->qtd_list);
407                 last = qtd;
408         }
409
410         /* last urb's completion might still need calling */
411         if (likely (last != NULL)) {
412                 ehci_urb_done (ehci, last->urb);
413                 count++;
414                 ehci_qtd_free (ehci, last);
415         }
416
417         /* restore original state; caller must unlink or relink */
418         qh->qh_state = state;
419
420         /* be sure the hardware's done with the qh before refreshing
421          * it after fault cleanup, or recovering from silicon wrongly
422          * overlaying the dummy qtd (which reduces DMA chatter).
423          */
424         if (stopped != 0 || qh->hw_qtd_next == EHCI_LIST_END(ehci)) {
425                 switch (state) {
426                 case QH_STATE_IDLE:
427                         qh_refresh(ehci, qh);
428                         break;
429                 case QH_STATE_LINKED:
430                         /* should be rare for periodic transfers,
431                          * except maybe high bandwidth ...
432                          */
433                         if ((cpu_to_hc32(ehci, QH_SMASK)
434                                         & qh->hw_info2) != 0) {
435                                 intr_deschedule (ehci, qh);
436                                 (void) qh_schedule (ehci, qh);
437                         } else
438                                 unlink_async (ehci, qh);
439                         break;
440                 /* otherwise, unlink already started */
441                 }
442         }
443
444         return count;
445 }
446
447 /*-------------------------------------------------------------------------*/
448
449 // high bandwidth multiplier, as encoded in highspeed endpoint descriptors
450 #define hb_mult(wMaxPacketSize) (1 + (((wMaxPacketSize) >> 11) & 0x03))
451 // ... and packet size, for any kind of endpoint descriptor
452 #define max_packet(wMaxPacketSize) ((wMaxPacketSize) & 0x07ff)
453
454 /*
455  * reverse of qh_urb_transaction:  free a list of TDs.
456  * used for cleanup after errors, before HC sees an URB's TDs.
457  */
458 static void qtd_list_free (
459         struct ehci_hcd         *ehci,
460         struct urb              *urb,
461         struct list_head        *qtd_list
462 ) {
463         struct list_head        *entry, *temp;
464
465         list_for_each_safe (entry, temp, qtd_list) {
466                 struct ehci_qtd *qtd;
467
468                 qtd = list_entry (entry, struct ehci_qtd, qtd_list);
469                 list_del (&qtd->qtd_list);
470                 ehci_qtd_free (ehci, qtd);
471         }
472 }
473
474 /*
475  * create a list of filled qtds for this URB; won't link into qh.
476  */
477 static struct list_head *
478 qh_urb_transaction (
479         struct ehci_hcd         *ehci,
480         struct urb              *urb,
481         struct list_head        *head,
482         gfp_t                   flags
483 ) {
484         struct ehci_qtd         *qtd, *qtd_prev;
485         dma_addr_t              buf;
486         int                     len, maxpacket;
487         int                     is_input;
488         u32                     token;
489
490         /*
491          * URBs map to sequences of QTDs:  one logical transaction
492          */
493         qtd = ehci_qtd_alloc (ehci, flags);
494         if (unlikely (!qtd))
495                 return NULL;
496         list_add_tail (&qtd->qtd_list, head);
497         qtd->urb = urb;
498
499         token = QTD_STS_ACTIVE;
500         token |= (EHCI_TUNE_CERR << 10);
501         /* for split transactions, SplitXState initialized to zero */
502
503         len = urb->transfer_buffer_length;
504         is_input = usb_pipein (urb->pipe);
505         if (usb_pipecontrol (urb->pipe)) {
506                 /* SETUP pid */
507                 qtd_fill(ehci, qtd, urb->setup_dma,
508                                 sizeof (struct usb_ctrlrequest),
509                                 token | (2 /* "setup" */ << 8), 8);
510
511                 /* ... and always at least one more pid */
512                 token ^= QTD_TOGGLE;
513                 qtd_prev = qtd;
514                 qtd = ehci_qtd_alloc (ehci, flags);
515                 if (unlikely (!qtd))
516                         goto cleanup;
517                 qtd->urb = urb;
518                 qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
519                 list_add_tail (&qtd->qtd_list, head);
520
521                 /* for zero length DATA stages, STATUS is always IN */
522                 if (len == 0)
523                         token |= (1 /* "in" */ << 8);
524         }
525
526         /*
527          * data transfer stage:  buffer setup
528          */
529         buf = urb->transfer_dma;
530
531         if (is_input)
532                 token |= (1 /* "in" */ << 8);
533         /* else it's already initted to "out" pid (0 << 8) */
534
535         maxpacket = max_packet(usb_maxpacket(urb->dev, urb->pipe, !is_input));
536
537         /*
538          * buffer gets wrapped in one or more qtds;
539          * last one may be "short" (including zero len)
540          * and may serve as a control status ack
541          */
542         for (;;) {
543                 int this_qtd_len;
544
545                 this_qtd_len = qtd_fill(ehci, qtd, buf, len, token, maxpacket);
546                 len -= this_qtd_len;
547                 buf += this_qtd_len;
548                 if (is_input)
549                         qtd->hw_alt_next = ehci->async->hw_alt_next;
550
551                 /* qh makes control packets use qtd toggle; maybe switch it */
552                 if ((maxpacket & (this_qtd_len + (maxpacket - 1))) == 0)
553                         token ^= QTD_TOGGLE;
554
555                 if (likely (len <= 0))
556                         break;
557
558                 qtd_prev = qtd;
559                 qtd = ehci_qtd_alloc (ehci, flags);
560                 if (unlikely (!qtd))
561                         goto cleanup;
562                 qtd->urb = urb;
563                 qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
564                 list_add_tail (&qtd->qtd_list, head);
565         }
566
567         /* unless the bulk/interrupt caller wants a chance to clean
568          * up after short reads, hc should advance qh past this urb
569          */
570         if (likely ((urb->transfer_flags & URB_SHORT_NOT_OK) == 0
571                                 || usb_pipecontrol (urb->pipe)))
572                 qtd->hw_alt_next = EHCI_LIST_END(ehci);
573
574         /*
575          * control requests may need a terminating data "status" ack;
576          * bulk ones may need a terminating short packet (zero length).
577          */
578         if (likely (urb->transfer_buffer_length != 0)) {
579                 int     one_more = 0;
580
581                 if (usb_pipecontrol (urb->pipe)) {
582                         one_more = 1;
583                         token ^= 0x0100;        /* "in" <--> "out"  */
584                         token |= QTD_TOGGLE;    /* force DATA1 */
585                 } else if (usb_pipebulk (urb->pipe)
586                                 && (urb->transfer_flags & URB_ZERO_PACKET)
587                                 && !(urb->transfer_buffer_length % maxpacket)) {
588                         one_more = 1;
589                 }
590                 if (one_more) {
591                         qtd_prev = qtd;
592                         qtd = ehci_qtd_alloc (ehci, flags);
593                         if (unlikely (!qtd))
594                                 goto cleanup;
595                         qtd->urb = urb;
596                         qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
597                         list_add_tail (&qtd->qtd_list, head);
598
599                         /* never any data in such packets */
600                         qtd_fill(ehci, qtd, 0, 0, token, 0);
601                 }
602         }
603
604         /* by default, enable interrupt on urb completion */
605         if (likely (!(urb->transfer_flags & URB_NO_INTERRUPT)))
606                 qtd->hw_token |= cpu_to_hc32(ehci, QTD_IOC);
607         return head;
608
609 cleanup:
610         qtd_list_free (ehci, urb, head);
611         return NULL;
612 }
613
614 /*-------------------------------------------------------------------------*/
615
616 // Would be best to create all qh's from config descriptors,
617 // when each interface/altsetting is established.  Unlink
618 // any previous qh and cancel its urbs first; endpoints are
619 // implicitly reset then (data toggle too).
620 // That'd mean updating how usbcore talks to HCDs. (2.7?)
621
622
623 /*
624  * Each QH holds a qtd list; a QH is used for everything except iso.
625  *
626  * For interrupt urbs, the scheduler must set the microframe scheduling
627  * mask(s) each time the QH gets scheduled.  For highspeed, that's
628  * just one microframe in the s-mask.  For split interrupt transactions
629  * there are additional complications: c-mask, maybe FSTNs.
630  */
631 static struct ehci_qh *
632 qh_make (
633         struct ehci_hcd         *ehci,
634         struct urb              *urb,
635         gfp_t                   flags
636 ) {
637         struct ehci_qh          *qh = ehci_qh_alloc (ehci, flags);
638         u32                     info1 = 0, info2 = 0;
639         int                     is_input, type;
640         int                     maxp = 0;
641
642         if (!qh)
643                 return qh;
644
645         /*
646          * init endpoint/device data for this QH
647          */
648         info1 |= usb_pipeendpoint (urb->pipe) << 8;
649         info1 |= usb_pipedevice (urb->pipe) << 0;
650
651         is_input = usb_pipein (urb->pipe);
652         type = usb_pipetype (urb->pipe);
653         maxp = usb_maxpacket (urb->dev, urb->pipe, !is_input);
654
655         /* Compute interrupt scheduling parameters just once, and save.
656          * - allowing for high bandwidth, how many nsec/uframe are used?
657          * - split transactions need a second CSPLIT uframe; same question
658          * - splits also need a schedule gap (for full/low speed I/O)
659          * - qh has a polling interval
660          *
661          * For control/bulk requests, the HC or TT handles these.
662          */
663         if (type == PIPE_INTERRUPT) {
664                 qh->usecs = NS_TO_US (usb_calc_bus_time (USB_SPEED_HIGH, is_input, 0,
665                                 hb_mult (maxp) * max_packet (maxp)));
666                 qh->start = NO_FRAME;
667
668                 if (urb->dev->speed == USB_SPEED_HIGH) {
669                         qh->c_usecs = 0;
670                         qh->gap_uf = 0;
671
672                         qh->period = urb->interval >> 3;
673                         if (qh->period == 0 && urb->interval != 1) {
674                                 /* NOTE interval 2 or 4 uframes could work.
675                                  * But interval 1 scheduling is simpler, and
676                                  * includes high bandwidth.
677                                  */
678                                 dbg ("intr period %d uframes, NYET!",
679                                                 urb->interval);
680                                 goto done;
681                         }
682                 } else {
683                         struct usb_tt   *tt = urb->dev->tt;
684                         int             think_time;
685
686                         /* gap is f(FS/LS transfer times) */
687                         qh->gap_uf = 1 + usb_calc_bus_time (urb->dev->speed,
688                                         is_input, 0, maxp) / (125 * 1000);
689
690                         /* FIXME this just approximates SPLIT/CSPLIT times */
691                         if (is_input) {         // SPLIT, gap, CSPLIT+DATA
692                                 qh->c_usecs = qh->usecs + HS_USECS (0);
693                                 qh->usecs = HS_USECS (1);
694                         } else {                // SPLIT+DATA, gap, CSPLIT
695                                 qh->usecs += HS_USECS (1);
696                                 qh->c_usecs = HS_USECS (0);
697                         }
698
699                         think_time = tt ? tt->think_time : 0;
700                         qh->tt_usecs = NS_TO_US (think_time +
701                                         usb_calc_bus_time (urb->dev->speed,
702                                         is_input, 0, max_packet (maxp)));
703                         qh->period = urb->interval;
704                 }
705         }
706
707         /* support for tt scheduling, and access to toggles */
708         qh->dev = urb->dev;
709
710         /* using TT? */
711         switch (urb->dev->speed) {
712         case USB_SPEED_LOW:
713                 info1 |= (1 << 12);     /* EPS "low" */
714                 /* FALL THROUGH */
715
716         case USB_SPEED_FULL:
717                 /* EPS 0 means "full" */
718                 if (type != PIPE_INTERRUPT)
719                         info1 |= (EHCI_TUNE_RL_TT << 28);
720                 if (type == PIPE_CONTROL) {
721                         info1 |= (1 << 27);     /* for TT */
722                         info1 |= 1 << 14;       /* toggle from qtd */
723                 }
724                 info1 |= maxp << 16;
725
726                 info2 |= (EHCI_TUNE_MULT_TT << 30);
727
728                 /* Some Freescale processors have an erratum in which the
729                  * port number in the queue head was 0..N-1 instead of 1..N.
730                  */
731                 if (ehci_has_fsl_portno_bug(ehci))
732                         info2 |= (urb->dev->ttport-1) << 23;
733                 else
734                         info2 |= urb->dev->ttport << 23;
735
736                 /* set the address of the TT; for TDI's integrated
737                  * root hub tt, leave it zeroed.
738                  */
739                 if (!ehci_is_TDI(ehci)
740                                 || urb->dev->tt->hub !=
741                                         ehci_to_hcd(ehci)->self.root_hub)
742                         info2 |= urb->dev->tt->hub->devnum << 16;
743
744                 /* NOTE:  if (PIPE_INTERRUPT) { scheduler sets c-mask } */
745
746                 break;
747
748         case USB_SPEED_HIGH:            /* no TT involved */
749                 info1 |= (2 << 12);     /* EPS "high" */
750                 if (type == PIPE_CONTROL) {
751                         info1 |= (EHCI_TUNE_RL_HS << 28);
752                         info1 |= 64 << 16;      /* usb2 fixed maxpacket */
753                         info1 |= 1 << 14;       /* toggle from qtd */
754                         info2 |= (EHCI_TUNE_MULT_HS << 30);
755                 } else if (type == PIPE_BULK) {
756                         info1 |= (EHCI_TUNE_RL_HS << 28);
757                         info1 |= 512 << 16;     /* usb2 fixed maxpacket */
758                         info2 |= (EHCI_TUNE_MULT_HS << 30);
759                 } else {                /* PIPE_INTERRUPT */
760                         info1 |= max_packet (maxp) << 16;
761                         info2 |= hb_mult (maxp) << 30;
762                 }
763                 break;
764         default:
765                 dbg ("bogus dev %p speed %d", urb->dev, urb->dev->speed);
766 done:
767                 qh_put (qh);
768                 return NULL;
769         }
770
771         /* NOTE:  if (PIPE_INTERRUPT) { scheduler sets s-mask } */
772
773         /* init as live, toggle clear, advance to dummy */
774         qh->qh_state = QH_STATE_IDLE;
775         qh->hw_info1 = cpu_to_hc32(ehci, info1);
776         qh->hw_info2 = cpu_to_hc32(ehci, info2);
777         usb_settoggle (urb->dev, usb_pipeendpoint (urb->pipe), !is_input, 1);
778         qh_refresh (ehci, qh);
779         return qh;
780 }
781
782 /*-------------------------------------------------------------------------*/
783
784 /* move qh (and its qtds) onto async queue; maybe enable queue.  */
785
786 static void qh_link_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
787 {
788         __hc32          dma = QH_NEXT(ehci, qh->qh_dma);
789         struct ehci_qh  *head;
790
791         /* (re)start the async schedule? */
792         head = ehci->async;
793         timer_action_done (ehci, TIMER_ASYNC_OFF);
794         if (!head->qh_next.qh) {
795                 u32     cmd = ehci_readl(ehci, &ehci->regs->command);
796
797                 if (!(cmd & CMD_ASE)) {
798                         /* in case a clear of CMD_ASE didn't take yet */
799                         (void)handshake(ehci, &ehci->regs->status,
800                                         STS_ASS, 0, 150);
801                         cmd |= CMD_ASE | CMD_RUN;
802                         ehci_writel(ehci, cmd, &ehci->regs->command);
803                         ehci_to_hcd(ehci)->state = HC_STATE_RUNNING;
804                         /* posted write need not be known to HC yet ... */
805                 }
806         }
807
808         /* clear halt and/or toggle; and maybe recover from silicon quirk */
809         if (qh->qh_state == QH_STATE_IDLE)
810                 qh_refresh (ehci, qh);
811
812         /* splice right after start */
813         qh->qh_next = head->qh_next;
814         qh->hw_next = head->hw_next;
815         wmb ();
816
817         head->qh_next.qh = qh;
818         head->hw_next = dma;
819
820         qh->qh_state = QH_STATE_LINKED;
821         /* qtd completions reported later by interrupt */
822 }
823
824 /*-------------------------------------------------------------------------*/
825
826 /*
827  * For control/bulk/interrupt, return QH with these TDs appended.
828  * Allocates and initializes the QH if necessary.
829  * Returns null if it can't allocate a QH it needs to.
830  * If the QH has TDs (urbs) already, that's great.
831  */
832 static struct ehci_qh *qh_append_tds (
833         struct ehci_hcd         *ehci,
834         struct urb              *urb,
835         struct list_head        *qtd_list,
836         int                     epnum,
837         void                    **ptr
838 )
839 {
840         struct ehci_qh          *qh = NULL;
841         u32                     qh_addr_mask = cpu_to_hc32(ehci, 0x7f);
842
843         qh = (struct ehci_qh *) *ptr;
844         if (unlikely (qh == NULL)) {
845                 /* can't sleep here, we have ehci->lock... */
846                 qh = qh_make (ehci, urb, GFP_ATOMIC);
847                 *ptr = qh;
848         }
849         if (likely (qh != NULL)) {
850                 struct ehci_qtd *qtd;
851
852                 if (unlikely (list_empty (qtd_list)))
853                         qtd = NULL;
854                 else
855                         qtd = list_entry (qtd_list->next, struct ehci_qtd,
856                                         qtd_list);
857
858                 /* control qh may need patching ... */
859                 if (unlikely (epnum == 0)) {
860
861                         /* usb_reset_device() briefly reverts to address 0 */
862                         if (usb_pipedevice (urb->pipe) == 0)
863                                 qh->hw_info1 &= ~qh_addr_mask;
864                 }
865
866                 /* just one way to queue requests: swap with the dummy qtd.
867                  * only hc or qh_refresh() ever modify the overlay.
868                  */
869                 if (likely (qtd != NULL)) {
870                         struct ehci_qtd         *dummy;
871                         dma_addr_t              dma;
872                         __hc32                  token;
873
874                         /* to avoid racing the HC, use the dummy td instead of
875                          * the first td of our list (becomes new dummy).  both
876                          * tds stay deactivated until we're done, when the
877                          * HC is allowed to fetch the old dummy (4.10.2).
878                          */
879                         token = qtd->hw_token;
880                         qtd->hw_token = HALT_BIT(ehci);
881                         wmb ();
882                         dummy = qh->dummy;
883
884                         dma = dummy->qtd_dma;
885                         *dummy = *qtd;
886                         dummy->qtd_dma = dma;
887
888                         list_del (&qtd->qtd_list);
889                         list_add (&dummy->qtd_list, qtd_list);
890                         __list_splice (qtd_list, qh->qtd_list.prev);
891
892                         ehci_qtd_init(ehci, qtd, qtd->qtd_dma);
893                         qh->dummy = qtd;
894
895                         /* hc must see the new dummy at list end */
896                         dma = qtd->qtd_dma;
897                         qtd = list_entry (qh->qtd_list.prev,
898                                         struct ehci_qtd, qtd_list);
899                         qtd->hw_next = QTD_NEXT(ehci, dma);
900
901                         /* let the hc process these next qtds */
902                         wmb ();
903                         dummy->hw_token = token;
904
905                         urb->hcpriv = qh_get (qh);
906                 }
907         }
908         return qh;
909 }
910
911 /*-------------------------------------------------------------------------*/
912
913 static int
914 submit_async (
915         struct ehci_hcd         *ehci,
916         struct usb_host_endpoint *ep,
917         struct urb              *urb,
918         struct list_head        *qtd_list,
919         gfp_t                   mem_flags
920 ) {
921         struct ehci_qtd         *qtd;
922         int                     epnum;
923         unsigned long           flags;
924         struct ehci_qh          *qh = NULL;
925         int                     rc = 0;
926
927         qtd = list_entry (qtd_list->next, struct ehci_qtd, qtd_list);
928         epnum = ep->desc.bEndpointAddress;
929
930 #ifdef EHCI_URB_TRACE
931         ehci_dbg (ehci,
932                 "%s %s urb %p ep%d%s len %d, qtd %p [qh %p]\n",
933                 __FUNCTION__, urb->dev->devpath, urb,
934                 epnum & 0x0f, (epnum & USB_DIR_IN) ? "in" : "out",
935                 urb->transfer_buffer_length,
936                 qtd, ep->hcpriv);
937 #endif
938
939         spin_lock_irqsave (&ehci->lock, flags);
940         if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE,
941                                &ehci_to_hcd(ehci)->flags))) {
942                 rc = -ESHUTDOWN;
943                 goto done;
944         }
945
946         qh = qh_append_tds (ehci, urb, qtd_list, epnum, &ep->hcpriv);
947         if (unlikely(qh == NULL)) {
948                 rc = -ENOMEM;
949                 goto done;
950         }
951
952         /* Control/bulk operations through TTs don't need scheduling,
953          * the HC and TT handle it when the TT has a buffer ready.
954          */
955         if (likely (qh->qh_state == QH_STATE_IDLE))
956                 qh_link_async (ehci, qh_get (qh));
957  done:
958         spin_unlock_irqrestore (&ehci->lock, flags);
959         if (unlikely (qh == NULL))
960                 qtd_list_free (ehci, urb, qtd_list);
961         return rc;
962 }
963
964 /*-------------------------------------------------------------------------*/
965
966 /* the async qh for the qtds being reclaimed are now unlinked from the HC */
967
968 static void end_unlink_async (struct ehci_hcd *ehci)
969 {
970         struct ehci_qh          *qh = ehci->reclaim;
971         struct ehci_qh          *next;
972
973         timer_action_done (ehci, TIMER_IAA_WATCHDOG);
974
975         // qh->hw_next = cpu_to_hc32(qh->qh_dma);
976         qh->qh_state = QH_STATE_IDLE;
977         qh->qh_next.qh = NULL;
978         qh_put (qh);                    // refcount from reclaim
979
980         /* other unlink(s) may be pending (in QH_STATE_UNLINK_WAIT) */
981         next = qh->reclaim;
982         ehci->reclaim = next;
983         ehci->reclaim_ready = 0;
984         qh->reclaim = NULL;
985
986         qh_completions (ehci, qh);
987
988         if (!list_empty (&qh->qtd_list)
989                         && HC_IS_RUNNING (ehci_to_hcd(ehci)->state))
990                 qh_link_async (ehci, qh);
991         else {
992                 qh_put (qh);            // refcount from async list
993
994                 /* it's not free to turn the async schedule on/off; leave it
995                  * active but idle for a while once it empties.
996                  */
997                 if (HC_IS_RUNNING (ehci_to_hcd(ehci)->state)
998                                 && ehci->async->qh_next.qh == NULL)
999                         timer_action (ehci, TIMER_ASYNC_OFF);
1000         }
1001
1002         if (next) {
1003                 ehci->reclaim = NULL;
1004                 start_unlink_async (ehci, next);
1005         }
1006 }
1007
1008 /* makes sure the async qh will become idle */
1009 /* caller must own ehci->lock */
1010
1011 static void start_unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
1012 {
1013         int             cmd = ehci_readl(ehci, &ehci->regs->command);
1014         struct ehci_qh  *prev;
1015
1016 #ifdef DEBUG
1017         assert_spin_locked(&ehci->lock);
1018         if (ehci->reclaim
1019                         || (qh->qh_state != QH_STATE_LINKED
1020                                 && qh->qh_state != QH_STATE_UNLINK_WAIT)
1021                         )
1022                 BUG ();
1023 #endif
1024
1025         /* stop async schedule right now? */
1026         if (unlikely (qh == ehci->async)) {
1027                 /* can't get here without STS_ASS set */
1028                 if (ehci_to_hcd(ehci)->state != HC_STATE_HALT
1029                                 && !ehci->reclaim) {
1030                         /* ... and CMD_IAAD clear */
1031                         ehci_writel(ehci, cmd & ~CMD_ASE,
1032                                     &ehci->regs->command);
1033                         wmb ();
1034                         // handshake later, if we need to
1035                         timer_action_done (ehci, TIMER_ASYNC_OFF);
1036                 }
1037                 return;
1038         }
1039
1040         qh->qh_state = QH_STATE_UNLINK;
1041         ehci->reclaim = qh = qh_get (qh);
1042
1043         prev = ehci->async;
1044         while (prev->qh_next.qh != qh)
1045                 prev = prev->qh_next.qh;
1046
1047         prev->hw_next = qh->hw_next;
1048         prev->qh_next = qh->qh_next;
1049         wmb ();
1050
1051         if (unlikely (ehci_to_hcd(ehci)->state == HC_STATE_HALT)) {
1052                 /* if (unlikely (qh->reclaim != 0))
1053                  *      this will recurse, probably not much
1054                  */
1055                 end_unlink_async (ehci);
1056                 return;
1057         }
1058
1059         ehci->reclaim_ready = 0;
1060         cmd |= CMD_IAAD;
1061         ehci_writel(ehci, cmd, &ehci->regs->command);
1062         (void)ehci_readl(ehci, &ehci->regs->command);
1063         timer_action (ehci, TIMER_IAA_WATCHDOG);
1064 }
1065
1066 /*-------------------------------------------------------------------------*/
1067
1068 static void scan_async (struct ehci_hcd *ehci)
1069 {
1070         struct ehci_qh          *qh;
1071         enum ehci_timer_action  action = TIMER_IO_WATCHDOG;
1072
1073         if (!++(ehci->stamp))
1074                 ehci->stamp++;
1075         timer_action_done (ehci, TIMER_ASYNC_SHRINK);
1076 rescan:
1077         qh = ehci->async->qh_next.qh;
1078         if (likely (qh != NULL)) {
1079                 do {
1080                         /* clean any finished work for this qh */
1081                         if (!list_empty (&qh->qtd_list)
1082                                         && qh->stamp != ehci->stamp) {
1083                                 int temp;
1084
1085                                 /* unlinks could happen here; completion
1086                                  * reporting drops the lock.  rescan using
1087                                  * the latest schedule, but don't rescan
1088                                  * qhs we already finished (no looping).
1089                                  */
1090                                 qh = qh_get (qh);
1091                                 qh->stamp = ehci->stamp;
1092                                 temp = qh_completions (ehci, qh);
1093                                 qh_put (qh);
1094                                 if (temp != 0) {
1095                                         goto rescan;
1096                                 }
1097                         }
1098
1099                         /* unlink idle entries, reducing HC PCI usage as well
1100                          * as HCD schedule-scanning costs.  delay for any qh
1101                          * we just scanned, there's a not-unusual case that it
1102                          * doesn't stay idle for long.
1103                          * (plus, avoids some kind of re-activation race.)
1104                          */
1105                         if (list_empty (&qh->qtd_list)) {
1106                                 if (qh->stamp == ehci->stamp)
1107                                         action = TIMER_ASYNC_SHRINK;
1108                                 else if (!ehci->reclaim
1109                                             && qh->qh_state == QH_STATE_LINKED)
1110                                         start_unlink_async (ehci, qh);
1111                         }
1112
1113                         qh = qh->qh_next.qh;
1114                 } while (qh);
1115         }
1116         if (action == TIMER_ASYNC_SHRINK)
1117                 timer_action (ehci, TIMER_ASYNC_SHRINK);
1118 }