summaryrefslogtreecommitdiff
path: root/drivers/usb/host/ohci-dbg.c
blob: d3ee1f52aaab2dc42864fb1e3464fa1b8ff4fa4b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
// SPDX-License-Identifier: GPL-1.0+
/*
 * OHCI HCD (Host Controller Driver) for USB.
 *
 * (C) Copyright 1999 Roman Weissgaerber <weissg@vienna.at>
 * (C) Copyright 2000-2002 David Brownell <dbrownell@users.sourceforge.net>
 *
 * This file is licenced under the GPL.
 */

/*-------------------------------------------------------------------------*/

#define edstring(ed_type) ({ char *temp; \
	switch (ed_type) { \
	case PIPE_CONTROL:	temp = "ctrl"; break; \
	case PIPE_BULK:		temp = "bulk"; break; \
	case PIPE_INTERRUPT:	temp = "intr"; break; \
	default:		temp = "isoc"; break; \
	} temp;})
#define pipestring(pipe) edstring(usb_pipetype(pipe))


#define ohci_dbg_sw(ohci, next, size, format, arg...) \
	do { \
	if (next != NULL) { \
		unsigned s_len; \
		s_len = scnprintf (*next, *size, format, ## arg ); \
		*size -= s_len; *next += s_len; \
	} else \
		ohci_dbg(ohci,format, ## arg ); \
	} while (0);

/* Version for use where "next" is the address of a local variable */
#define ohci_dbg_nosw(ohci, next, size, format, arg...) \
	do { \
		unsigned s_len; \
		s_len = scnprintf(*next, *size, format, ## arg); \
		*size -= s_len; *next += s_len; \
	} while (0);


static void ohci_dump_intr_mask (
	struct ohci_hcd *ohci,
	char *label,
	u32 mask,
	char **next,
	unsigned *size)
{
	ohci_dbg_sw (ohci, next, size, "%s 0x%08x%s%s%s%s%s%s%s%s%s\n",
		label,
		mask,
		(mask & OHCI_INTR_MIE) ? " MIE" : "",
		(mask & OHCI_INTR_OC) ? " OC" : "",
		(mask & OHCI_INTR_RHSC) ? " RHSC" : "",
		(mask & OHCI_INTR_FNO) ? " FNO" : "",
		(mask & OHCI_INTR_UE) ? " UE" : "",
		(mask & OHCI_INTR_RD) ? " RD" : "",
		(mask & OHCI_INTR_SF) ? " SF" : "",
		(mask & OHCI_INTR_WDH) ? " WDH" : "",
		(mask & OHCI_INTR_SO) ? " SO" : ""
		);
}

static void maybe_print_eds (
	struct ohci_hcd *ohci,
	char *label,
	u32 value,
	char **next,
	unsigned *size)
{
	if (value)
		ohci_dbg_sw (ohci, next, size, "%s %08x\n", label, value);
}

static char *hcfs2string (int state)
{
	switch (state) {
		case OHCI_USB_RESET:	return "reset";
		case OHCI_USB_RESUME:	return "resume";
		case OHCI_USB_OPER:	return "operational";
		case OHCI_USB_SUSPEND:	return "suspend";
	}
	return "?";
}

static const char *rh_state_string(struct ohci_hcd *ohci)
{
	switch (ohci->rh_state) {
	case OHCI_RH_HALTED:
		return "halted";
	case OHCI_RH_SUSPENDED:
		return "suspended";
	case OHCI_RH_RUNNING:
		return "running";
	}
	return "?";
}

// dump control and status registers
static void
ohci_dump_status (struct ohci_hcd *controller, char **next, unsigned *size)
{
	struct ohci_regs __iomem *regs = controller->regs;
	u32			temp;

	temp = ohci_readl (controller, &regs->revision) & 0xff;
	ohci_dbg_sw (controller, next, size,
		"OHCI %d.%d, %s legacy support registers, rh state %s\n",
		0x03 & (temp >> 4), (temp & 0x0f),
		(temp & 0x0100) ? "with" : "NO",
		rh_state_string(controller));

	temp = ohci_readl (controller, &regs->control);
	ohci_dbg_sw (controller, next, size,
		"control 0x%03x%s%s%s HCFS=%s%s%s%s%s CBSR=%d\n",
		temp,
		(temp & OHCI_CTRL_RWE) ? " RWE" : "",
		(temp & OHCI_CTRL_RWC) ? " RWC" : "",
		(temp & OHCI_CTRL_IR) ? " IR" : "",
		hcfs2string (temp & OHCI_CTRL_HCFS),
		(temp & OHCI_CTRL_BLE) ? " BLE" : "",
		(temp & OHCI_CTRL_CLE) ? " CLE" : "",
		(temp & OHCI_CTRL_IE) ? " IE" : "",
		(temp & OHCI_CTRL_PLE) ? " PLE" : "",
		temp & OHCI_CTRL_CBSR
		);

	temp = ohci_readl (controller, &regs->cmdstatus);
	ohci_dbg_sw (controller, next, size,
		"cmdstatus 0x%05x SOC=%d%s%s%s%s\n", temp,
		(temp & OHCI_SOC) >> 16,
		(temp & OHCI_OCR) ? " OCR" : "",
		(temp & OHCI_BLF) ? " BLF" : "",
		(temp & OHCI_CLF) ? " CLF" : "",
		(temp & OHCI_HCR) ? " HCR" : ""
		);

	ohci_dump_intr_mask (controller, "intrstatus",
			ohci_readl (controller, &regs->intrstatus),
			next, size);
	ohci_dump_intr_mask (controller, "intrenable",
			ohci_readl (controller, &regs->intrenable),
			next, size);
	// intrdisable always same as intrenable

	maybe_print_eds (controller, "ed_periodcurrent",
			ohci_readl (controller, &regs->ed_periodcurrent),
			next, size);

	maybe_print_eds (controller, "ed_controlhead",
			ohci_readl (controller, &regs->ed_controlhead),
			next, size);
	maybe_print_eds (controller, "ed_controlcurrent",
			ohci_readl (controller, &regs->ed_controlcurrent),
			next, size);

	maybe_print_eds (controller, "ed_bulkhead",
			ohci_readl (controller, &regs->ed_bulkhead),
			next, size);
	maybe_print_eds (controller, "ed_bulkcurrent",
			ohci_readl (controller, &regs->ed_bulkcurrent),
			next, size);

	maybe_print_eds (controller, "donehead",
			ohci_readl (controller, &regs->donehead), next, size);
}

#define dbg_port_sw(hc,num,value,next,size) \
	ohci_dbg_sw (hc, next, size, \
		"roothub.portstatus [%d] " \
		"0x%08x%s%s%s%s%s%s%s%s%s%s%s%s\n", \
		num, temp, \
		(temp & RH_PS_PRSC) ? " PRSC" : "", \
		(temp & RH_PS_OCIC) ? " OCIC" : "", \
		(temp & RH_PS_PSSC) ? " PSSC" : "", \
		(temp & RH_PS_PESC) ? " PESC" : "", \
		(temp & RH_PS_CSC) ? " CSC" : "", \
		\
		(temp & RH_PS_LSDA) ? " LSDA" : "", \
		(temp & RH_PS_PPS) ? " PPS" : "", \
		(temp & RH_PS_PRS) ? " PRS" : "", \
		(temp & RH_PS_POCI) ? " POCI" : "", \
		(temp & RH_PS_PSS) ? " PSS" : "", \
		\
		(temp & RH_PS_PES) ? " PES" : "", \
		(temp & RH_PS_CCS) ? " CCS" : "" \
		);


static void
ohci_dump_roothub (
	struct ohci_hcd *controller,
	int verbose,
	char **next,
	unsigned *size)
{
	u32			temp, i;

	temp = roothub_a (controller);
	if (temp == ~(u32)0)
		return;

	if (verbose) {
		ohci_dbg_sw (controller, next, size,
			"roothub.a %08x POTPGT=%d%s%s%s%s%s NDP=%d(%d)\n", temp,
			((temp & RH_A_POTPGT) >> 24) & 0xff,
			(temp & RH_A_NOCP) ? " NOCP" : "",
			(temp & RH_A_OCPM) ? " OCPM" : "",
			(temp & RH_A_DT) ? " DT" : "",
			(temp & RH_A_NPS) ? " NPS" : "",
			(temp & RH_A_PSM) ? " PSM" : "",
			(temp & RH_A_NDP), controller->num_ports
			);
		temp = roothub_b (controller);
		ohci_dbg_sw (controller, next, size,
			"roothub.b %08x PPCM=%04x DR=%04x\n",
			temp,
			(temp & RH_B_PPCM) >> 16,
			(temp & RH_B_DR)
			);
		temp = roothub_status (controller);
		ohci_dbg_sw (controller, next, size,
			"roothub.status %08x%s%s%s%s%s%s\n",
			temp,
			(temp & RH_HS_CRWE) ? " CRWE" : "",
			(temp & RH_HS_OCIC) ? " OCIC" : "",
			(temp & RH_HS_LPSC) ? " LPSC" : "",
			(temp & RH_HS_DRWE) ? " DRWE" : "",
			(temp & RH_HS_OCI) ? " OCI" : "",
			(temp & RH_HS_LPS) ? " LPS" : ""
			);
	}

	for (i = 0; i < controller->num_ports; i++) {
		temp = roothub_portstatus (controller, i);
		dbg_port_sw (controller, i, temp, next, size);
	}
}

static void ohci_dump(struct ohci_hcd *controller)
{
	ohci_dbg (controller, "OHCI controller state\n");

	// dumps some of the state we know about
	ohci_dump_status (controller, NULL, NULL);
	if (controller->hcca)
		ohci_dbg (controller,
			"hcca frame #%04x\n", ohci_frame_no(controller));
	ohci_dump_roothub (controller, 1, NULL, NULL);
}

static const char data0 [] = "DATA0";
static const char data1 [] = "DATA1";

static void ohci_dump_td (const struct ohci_hcd *ohci, const char *label,
		const struct td *td)
{
	u32	tmp = hc32_to_cpup (ohci, &td->hwINFO);

	ohci_dbg (ohci, "%s td %p%s; urb %p index %d; hw next td %08x\n",
		label, td,
		(tmp & TD_DONE) ? " (DONE)" : "",
		td->urb, td->index,
		hc32_to_cpup (ohci, &td->hwNextTD));
	if ((tmp & TD_ISO) == 0) {
		const char	*toggle, *pid;
		u32	cbp, be;

		switch (tmp & TD_T) {
		case TD_T_DATA0: toggle = data0; break;
		case TD_T_DATA1: toggle = data1; break;
		case TD_T_TOGGLE: toggle = "(CARRY)"; break;
		default: toggle = "(?)"; break;
		}
		switch (tmp & TD_DP) {
		case TD_DP_SETUP: pid = "SETUP"; break;
		case TD_DP_IN: pid = "IN"; break;
		case TD_DP_OUT: pid = "OUT"; break;
		default: pid = "(bad pid)"; break;
		}
		ohci_dbg (ohci, "     info %08x CC=%x %s DI=%d %s %s\n", tmp,
			TD_CC_GET(tmp), /* EC, */ toggle,
			(tmp & TD_DI) >> 21, pid,
			(tmp & TD_R) ? "R" : "");
		cbp = hc32_to_cpup (ohci, &td->hwCBP);
		be = hc32_to_cpup (ohci, &td->hwBE);
		ohci_dbg (ohci, "     cbp %08x be %08x (len %d)\n", cbp, be,
			cbp ? (be + 1 - cbp) : 0);
	} else {
		unsigned	i;
		ohci_dbg (ohci, "  info %08x CC=%x FC=%d DI=%d SF=%04x\n", tmp,
			TD_CC_GET(tmp),
			(tmp >> 24) & 0x07,
			(tmp & TD_DI) >> 21,
			tmp & 0x0000ffff);
		ohci_dbg (ohci, "  bp0 %08x be %08x\n",
			hc32_to_cpup (ohci, &td->hwCBP) & ~0x0fff,
			hc32_to_cpup (ohci, &td->hwBE));
		for (i = 0; i < MAXPSW; i++) {
			u16	psw = ohci_hwPSW (ohci, td, i);
			int	cc = (psw >> 12) & 0x0f;
			ohci_dbg (ohci, "    psw [%d] = %2x, CC=%x %s=%d\n", i,
				psw, cc,
				(cc >= 0x0e) ? "OFFSET" : "SIZE",
				psw & 0x0fff);
		}
	}
}

/* caller MUST own hcd spinlock if verbose is set! */
static void __maybe_unused
ohci_dump_ed (const struct ohci_hcd *ohci, const char *label,
		const struct ed *ed, int verbose)
{
	u32	tmp = hc32_to_cpu (ohci, ed->hwINFO);
	char	*type = "";

	ohci_dbg (ohci, "%s, ed %p state 0x%x type %s; next ed %08x\n",
		label,
		ed, ed->state, edstring (ed->type),
		hc32_to_cpup (ohci, &ed->hwNextED));
	switch (tmp & (ED_IN|ED_OUT)) {
	case ED_OUT: type = "-OUT"; break;
	case ED_IN: type = "-IN"; break;
	/* else from TDs ... control */
	}
	ohci_dbg (ohci,
		"  info %08x MAX=%d%s%s%s%s EP=%d%s DEV=%d\n", tmp,
		0x03ff & (tmp >> 16),
		(tmp & ED_DEQUEUE) ? " DQ" : "",
		(tmp & ED_ISO) ? " ISO" : "",
		(tmp & ED_SKIP) ? " SKIP" : "",
		(tmp & ED_LOWSPEED) ? " LOW" : "",
		0x000f & (tmp >> 7),
		type,
		0x007f & tmp);
	tmp = hc32_to_cpup (ohci, &ed->hwHeadP);
	ohci_dbg (ohci, "  tds: head %08x %s%s tail %08x%s\n",
		tmp,
		(tmp & ED_C) ? data1 : data0,
		(tmp & ED_H) ? " HALT" : "",
		hc32_to_cpup (ohci, &ed->hwTailP),
		verbose ? "" : " (not listing)");
	if (verbose) {
		struct list_head	*tmp;

		/* use ed->td_list because HC concurrently modifies
		 * hwNextTD as it accumulates ed_donelist.
		 */
		list_for_each (tmp, &ed->td_list) {
			struct td		*td;
			td = list_entry (tmp, struct td, td_list);
			ohci_dump_td (ohci, "  ->", td);
		}
	}
}

/*-------------------------------------------------------------------------*/

static int debug_async_open(struct inode *, struct file *);
static int debug_periodic_open(struct inode *, struct file *);
static int debug_registers_open(struct inode *, struct file *);
static int debug_async_open(struct inode *, struct file *);
static ssize_t debug_output(struct file*, char __user*, size_t, loff_t*);
static int debug_close(struct inode *, struct file *);

static const struct file_operations debug_async_fops = {
	.owner		= THIS_MODULE,
	.open		= debug_async_open,
	.read		= debug_output,
	.release	= debug_close,
	.llseek		= default_llseek,
};
static const struct file_operations debug_periodic_fops = {
	.owner		= THIS_MODULE,
	.open		= debug_periodic_open,
	.read		= debug_output,
	.release	= debug_close,
	.llseek		= default_llseek,
};
static const struct file_operations debug_registers_fops = {
	.owner		= THIS_MODULE,
	.open		= debug_registers_open,
	.read		= debug_output,
	.release	= debug_close,
	.llseek		= default_llseek,
};

static struct dentry *ohci_debug_root;

struct debug_buffer {
	ssize_t (*fill_func)(struct debug_buffer *);	/* fill method */
	struct ohci_hcd *ohci;
	struct mutex mutex;	/* protect filling of buffer */
	size_t count;		/* number of characters filled into buffer */
	char *page;
};

static ssize_t
show_list (struct ohci_hcd *ohci, char *buf, size_t count, struct ed *ed)
{
	unsigned		temp, size = count;

	if (!ed)
		return 0;

	/* print first --> last */
	while (ed->ed_prev)
		ed = ed->ed_prev;

	/* dump a snapshot of the bulk or control schedule */
	while (ed) {
		u32		info = hc32_to_cpu (ohci, ed->hwINFO);
		u32		headp = hc32_to_cpu (ohci, ed->hwHeadP);
		struct list_head *entry;
		struct td	*td;

		temp = scnprintf (buf, size,
			"ed/%p %cs dev%d ep%d%s max %d %08x%s%s %s",
			ed,
			(info & ED_LOWSPEED) ? 'l' : 'f',
			info & 0x7f,
			(info >> 7) & 0xf,
			(info & ED_IN) ? "in" : "out",
			0x03ff & (info >> 16),
			info,
			(info & ED_SKIP) ? " s" : "",
			(headp & ED_H) ? " H" : "",
			(headp & ED_C) ? data1 : data0);
		size -= temp;
		buf += temp;

		list_for_each (entry, &ed->td_list) {
			u32		cbp, be;

			td = list_entry (entry, struct td, td_list);
			info = hc32_to_cpup (ohci, &td->hwINFO);
			cbp = hc32_to_cpup (ohci, &td->hwCBP);
			be = hc32_to_cpup (ohci, &td->hwBE);
			temp = scnprintf (buf, size,
					"\n\ttd %p %s %d cc=%x urb %p (%08x)",
					td,
					({ char *pid;
					switch (info & TD_DP) {
					case TD_DP_SETUP: pid = "setup"; break;
					case TD_DP_IN: pid = "in"; break;
					case TD_DP_OUT: pid = "out"; break;
					default: pid = "(?)"; break;
					 } pid;}),
					cbp ? (be + 1 - cbp) : 0,
					TD_CC_GET (info), td->urb, info);
			size -= temp;
			buf += temp;
		}

		temp = scnprintf (buf, size, "\n");
		size -= temp;
		buf += temp;

		ed = ed->ed_next;
	}
	return count - size;
}

static ssize_t fill_async_buffer(struct debug_buffer *buf)
{
	struct ohci_hcd		*ohci;
	size_t			temp, size;
	unsigned long		flags;

	ohci = buf->ohci;
	size = PAGE_SIZE;

	/* display control and bulk lists together, for simplicity */
	spin_lock_irqsave (&ohci->lock, flags);
	temp = show_list(ohci, buf->page, size, ohci->ed_controltail);
	temp += show_list(ohci, buf->page + temp, size - temp,
			  ohci->ed_bulktail);
	spin_unlock_irqrestore (&ohci->lock, flags);

	return temp;
}

#define DBG_SCHED_LIMIT 64

static ssize_t fill_periodic_buffer(struct debug_buffer *buf)
{
	struct ohci_hcd		*ohci;
	struct ed		**seen, *ed;
	unsigned long		flags;
	unsigned		temp, size, seen_count;
	char			*next;
	unsigned		i;

	seen = kmalloc(DBG_SCHED_LIMIT * sizeof *seen, GFP_ATOMIC);
	if (!seen)
		return 0;
	seen_count = 0;

	ohci = buf->ohci;
	next = buf->page;
	size = PAGE_SIZE;

	temp = scnprintf (next, size, "size = %d\n", NUM_INTS);
	size -= temp;
	next += temp;

	/* dump a snapshot of the periodic schedule (and load) */
	spin_lock_irqsave (&ohci->lock, flags);
	for (i = 0; i < NUM_INTS; i++) {
		ed = ohci->periodic[i];
		if (!ed)
			continue;

		temp = scnprintf (next, size, "%2d [%3d]:", i, ohci->load [i]);
		size -= temp;
		next += temp;

		do {
			temp = scnprintf (next, size, " ed%d/%p",
				ed->interval, ed);
			size -= temp;
			next += temp;
			for (temp = 0; temp < seen_count; temp++) {
				if (seen [temp] == ed)
					break;
			}

			/* show more info the first time around */
			if (temp == seen_count) {
				u32	info = hc32_to_cpu (ohci, ed->hwINFO);
				struct list_head	*entry;
				unsigned		qlen = 0;

				/* qlen measured here in TDs, not urbs */
				list_for_each (entry, &ed->td_list)
					qlen++;

				temp = scnprintf (next, size,
					" (%cs dev%d ep%d%s-%s qlen %u"
					" max %d %08x%s%s)",
					(info & ED_LOWSPEED) ? 'l' : 'f',
					info & 0x7f,
					(info >> 7) & 0xf,
					(info & ED_IN) ? "in" : "out",
					(info & ED_ISO) ? "iso" : "int",
					qlen,
					0x03ff & (info >> 16),
					info,
					(info & ED_SKIP) ? " K" : "",
					(ed->hwHeadP &
						cpu_to_hc32(ohci, ED_H)) ?
							" H" : "");
				size -= temp;
				next += temp;

				if (seen_count < DBG_SCHED_LIMIT)
					seen [seen_count++] = ed;

				ed = ed->ed_next;

			} else {
				/* we've seen it and what's after */
				temp = 0;
				ed = NULL;
			}

		} while (ed);

		temp = scnprintf (next, size, "\n");
		size -= temp;
		next += temp;
	}
	spin_unlock_irqrestore (&ohci->lock, flags);
	kfree (seen);

	return PAGE_SIZE - size;
}
#undef DBG_SCHED_LIMIT

static ssize_t fill_registers_buffer(struct debug_buffer *buf)
{
	struct usb_hcd		*hcd;
	struct ohci_hcd		*ohci;
	struct ohci_regs __iomem *regs;
	unsigned long		flags;
	unsigned		temp, size;
	char			*next;
	u32			rdata;

	ohci = buf->ohci;
	hcd = ohci_to_hcd(ohci);
	regs = ohci->regs;
	next = buf->page;
	size = PAGE_SIZE;

	spin_lock_irqsave (&ohci->lock, flags);

	/* dump driver info, then registers in spec order */

	ohci_dbg_nosw(ohci, &next, &size,
		"bus %s, device %s\n"
		"%s\n"
		"%s\n",
		hcd->self.controller->bus->name,
		dev_name(hcd->self.controller),
		hcd->product_desc,
		hcd_name);

	if (!HCD_HW_ACCESSIBLE(hcd)) {
		size -= scnprintf (next, size,
			"SUSPENDED (no register access)\n");
		goto done;
	}

	ohci_dump_status(ohci, &next, &size);

	/* hcca */
	if (ohci->hcca)
		ohci_dbg_nosw(ohci, &next, &size,
			"hcca frame 0x%04x\n", ohci_frame_no(ohci));

	/* other registers mostly affect frame timings */
	rdata = ohci_readl (ohci, &regs->fminterval);
	temp = scnprintf (next, size,
			"fmintvl 0x%08x %sFSMPS=0x%04x FI=0x%04x\n",
			rdata, (rdata >> 31) ? "FIT " : "",
			(rdata >> 16) & 0xefff, rdata & 0xffff);
	size -= temp;
	next += temp;

	rdata = ohci_readl (ohci, &regs->fmremaining);
	temp = scnprintf (next, size, "fmremaining 0x%08x %sFR=0x%04x\n",
			rdata, (rdata >> 31) ? "FRT " : "",
			rdata & 0x3fff);
	size -= temp;
	next += temp;

	rdata = ohci_readl (ohci, &regs->periodicstart);
	temp = scnprintf (next, size, "periodicstart 0x%04x\n",
			rdata & 0x3fff);
	size -= temp;
	next += temp;

	rdata = ohci_readl (ohci, &regs->lsthresh);
	temp = scnprintf (next, size, "lsthresh 0x%04x\n",
			rdata & 0x3fff);
	size -= temp;
	next += temp;

	temp = scnprintf (next, size, "hub poll timer %s\n",
			HCD_POLL_RH(ohci_to_hcd(ohci)) ? "ON" : "off");
	size -= temp;
	next += temp;

	/* roothub */
	ohci_dump_roothub (ohci, 1, &next, &size);

done:
	spin_unlock_irqrestore (&ohci->lock, flags);

	return PAGE_SIZE - size;
}

static struct debug_buffer *alloc_buffer(struct ohci_hcd *ohci,
				ssize_t (*fill_func)(struct debug_buffer *))
{
	struct debug_buffer *buf;

	buf = kzalloc(sizeof(struct debug_buffer), GFP_KERNEL);

	if (buf) {
		buf->ohci = ohci;
		buf->fill_func = fill_func;
		mutex_init(&buf->mutex);
	}

	return buf;
}

static int fill_buffer(struct debug_buffer *buf)
{
	int ret = 0;

	if (!buf->page)
		buf->page = (char *)get_zeroed_page(GFP_KERNEL);

	if (!buf->page) {
		ret = -ENOMEM;
		goto out;
	}

	ret = buf->fill_func(buf);

	if (ret >= 0) {
		buf->count = ret;
		ret = 0;
	}

out:
	return ret;
}

static ssize_t debug_output(struct file *file, char __user *user_buf,
			size_t len, loff_t *offset)
{
	struct debug_buffer *buf = file->private_data;
	int ret = 0;

	mutex_lock(&buf->mutex);
	if (buf->count == 0) {
		ret = fill_buffer(buf);
		if (ret != 0) {
			mutex_unlock(&buf->mutex);
			goto out;
		}
	}
	mutex_unlock(&buf->mutex);

	ret = simple_read_from_buffer(user_buf, len, offset,
				      buf->page, buf->count);

out:
	return ret;

}

static int debug_close(struct inode *inode, struct file *file)
{
	struct debug_buffer *buf = file->private_data;

	if (buf) {
		if (buf->page)
			free_page((unsigned long)buf->page);
		kfree(buf);
	}

	return 0;
}
static int debug_async_open(struct inode *inode, struct file *file)
{
	file->private_data = alloc_buffer(inode->i_private, fill_async_buffer);

	return file->private_data ? 0 : -ENOMEM;
}

static int debug_periodic_open(struct inode *inode, struct file *file)
{
	file->private_data = alloc_buffer(inode->i_private,
					  fill_periodic_buffer);

	return file->private_data ? 0 : -ENOMEM;
}

static int debug_registers_open(struct inode *inode, struct file *file)
{
	file->private_data = alloc_buffer(inode->i_private,
					  fill_registers_buffer);

	return file->private_data ? 0 : -ENOMEM;
}
static inline void create_debug_files (struct ohci_hcd *ohci)
{
	struct usb_bus *bus = &ohci_to_hcd(ohci)->self;
	struct dentry *root;

	root = debugfs_create_dir(bus->bus_name, ohci_debug_root);
	ohci->debug_dir = root;

	debugfs_create_file("async", S_IRUGO, root, ohci, &debug_async_fops);
	debugfs_create_file("periodic", S_IRUGO, root, ohci,
			    &debug_periodic_fops);
	debugfs_create_file("registers", S_IRUGO, root, ohci,
			    &debug_registers_fops);

	ohci_dbg (ohci, "created debug files\n");
}

static inline void remove_debug_files (struct ohci_hcd *ohci)
{
	debugfs_remove_recursive(ohci->debug_dir);
}

/*-------------------------------------------------------------------------*/