xref: /openbmc/linux/drivers/usb/host/ohci-dbg.c (revision fb574682)
1 // SPDX-License-Identifier: GPL-1.0+
2 /*
3  * OHCI HCD (Host Controller Driver) for USB.
4  *
5  * (C) Copyright 1999 Roman Weissgaerber <weissg@vienna.at>
6  * (C) Copyright 2000-2002 David Brownell <dbrownell@users.sourceforge.net>
7  *
8  * This file is licenced under the GPL.
9  */
10 
11 /*-------------------------------------------------------------------------*/
12 
13 #define edstring(ed_type) ({ char *temp; \
14 	switch (ed_type) { \
15 	case PIPE_CONTROL:	temp = "ctrl"; break; \
16 	case PIPE_BULK:		temp = "bulk"; break; \
17 	case PIPE_INTERRUPT:	temp = "intr"; break; \
18 	default:		temp = "isoc"; break; \
19 	} temp;})
20 #define pipestring(pipe) edstring(usb_pipetype(pipe))
21 
22 
23 #define ohci_dbg_sw(ohci, next, size, format, arg...) \
24 	do { \
25 	if (next != NULL) { \
26 		unsigned s_len; \
27 		s_len = scnprintf (*next, *size, format, ## arg ); \
28 		*size -= s_len; *next += s_len; \
29 	} else \
30 		ohci_dbg(ohci,format, ## arg ); \
31 	} while (0);
32 
33 /* Version for use where "next" is the address of a local variable */
34 #define ohci_dbg_nosw(ohci, next, size, format, arg...) \
35 	do { \
36 		unsigned s_len; \
37 		s_len = scnprintf(*next, *size, format, ## arg); \
38 		*size -= s_len; *next += s_len; \
39 	} while (0);
40 
41 
42 static void ohci_dump_intr_mask (
43 	struct ohci_hcd *ohci,
44 	char *label,
45 	u32 mask,
46 	char **next,
47 	unsigned *size)
48 {
49 	ohci_dbg_sw (ohci, next, size, "%s 0x%08x%s%s%s%s%s%s%s%s%s\n",
50 		label,
51 		mask,
52 		(mask & OHCI_INTR_MIE) ? " MIE" : "",
53 		(mask & OHCI_INTR_OC) ? " OC" : "",
54 		(mask & OHCI_INTR_RHSC) ? " RHSC" : "",
55 		(mask & OHCI_INTR_FNO) ? " FNO" : "",
56 		(mask & OHCI_INTR_UE) ? " UE" : "",
57 		(mask & OHCI_INTR_RD) ? " RD" : "",
58 		(mask & OHCI_INTR_SF) ? " SF" : "",
59 		(mask & OHCI_INTR_WDH) ? " WDH" : "",
60 		(mask & OHCI_INTR_SO) ? " SO" : ""
61 		);
62 }
63 
64 static void maybe_print_eds (
65 	struct ohci_hcd *ohci,
66 	char *label,
67 	u32 value,
68 	char **next,
69 	unsigned *size)
70 {
71 	if (value)
72 		ohci_dbg_sw (ohci, next, size, "%s %08x\n", label, value);
73 }
74 
75 static char *hcfs2string (int state)
76 {
77 	switch (state) {
78 		case OHCI_USB_RESET:	return "reset";
79 		case OHCI_USB_RESUME:	return "resume";
80 		case OHCI_USB_OPER:	return "operational";
81 		case OHCI_USB_SUSPEND:	return "suspend";
82 	}
83 	return "?";
84 }
85 
86 static const char *rh_state_string(struct ohci_hcd *ohci)
87 {
88 	switch (ohci->rh_state) {
89 	case OHCI_RH_HALTED:
90 		return "halted";
91 	case OHCI_RH_SUSPENDED:
92 		return "suspended";
93 	case OHCI_RH_RUNNING:
94 		return "running";
95 	}
96 	return "?";
97 }
98 
99 // dump control and status registers
100 static void
101 ohci_dump_status (struct ohci_hcd *controller, char **next, unsigned *size)
102 {
103 	struct ohci_regs __iomem *regs = controller->regs;
104 	u32			temp;
105 
106 	temp = ohci_readl (controller, &regs->revision) & 0xff;
107 	ohci_dbg_sw (controller, next, size,
108 		"OHCI %d.%d, %s legacy support registers, rh state %s\n",
109 		0x03 & (temp >> 4), (temp & 0x0f),
110 		(temp & 0x0100) ? "with" : "NO",
111 		rh_state_string(controller));
112 
113 	temp = ohci_readl (controller, &regs->control);
114 	ohci_dbg_sw (controller, next, size,
115 		"control 0x%03x%s%s%s HCFS=%s%s%s%s%s CBSR=%d\n",
116 		temp,
117 		(temp & OHCI_CTRL_RWE) ? " RWE" : "",
118 		(temp & OHCI_CTRL_RWC) ? " RWC" : "",
119 		(temp & OHCI_CTRL_IR) ? " IR" : "",
120 		hcfs2string (temp & OHCI_CTRL_HCFS),
121 		(temp & OHCI_CTRL_BLE) ? " BLE" : "",
122 		(temp & OHCI_CTRL_CLE) ? " CLE" : "",
123 		(temp & OHCI_CTRL_IE) ? " IE" : "",
124 		(temp & OHCI_CTRL_PLE) ? " PLE" : "",
125 		temp & OHCI_CTRL_CBSR
126 		);
127 
128 	temp = ohci_readl (controller, &regs->cmdstatus);
129 	ohci_dbg_sw (controller, next, size,
130 		"cmdstatus 0x%05x SOC=%d%s%s%s%s\n", temp,
131 		(temp & OHCI_SOC) >> 16,
132 		(temp & OHCI_OCR) ? " OCR" : "",
133 		(temp & OHCI_BLF) ? " BLF" : "",
134 		(temp & OHCI_CLF) ? " CLF" : "",
135 		(temp & OHCI_HCR) ? " HCR" : ""
136 		);
137 
138 	ohci_dump_intr_mask (controller, "intrstatus",
139 			ohci_readl (controller, &regs->intrstatus),
140 			next, size);
141 	ohci_dump_intr_mask (controller, "intrenable",
142 			ohci_readl (controller, &regs->intrenable),
143 			next, size);
144 	// intrdisable always same as intrenable
145 
146 	maybe_print_eds (controller, "ed_periodcurrent",
147 			ohci_readl (controller, &regs->ed_periodcurrent),
148 			next, size);
149 
150 	maybe_print_eds (controller, "ed_controlhead",
151 			ohci_readl (controller, &regs->ed_controlhead),
152 			next, size);
153 	maybe_print_eds (controller, "ed_controlcurrent",
154 			ohci_readl (controller, &regs->ed_controlcurrent),
155 			next, size);
156 
157 	maybe_print_eds (controller, "ed_bulkhead",
158 			ohci_readl (controller, &regs->ed_bulkhead),
159 			next, size);
160 	maybe_print_eds (controller, "ed_bulkcurrent",
161 			ohci_readl (controller, &regs->ed_bulkcurrent),
162 			next, size);
163 
164 	maybe_print_eds (controller, "donehead",
165 			ohci_readl (controller, &regs->donehead), next, size);
166 }
167 
168 #define dbg_port_sw(hc,num,value,next,size) \
169 	ohci_dbg_sw (hc, next, size, \
170 		"roothub.portstatus [%d] " \
171 		"0x%08x%s%s%s%s%s%s%s%s%s%s%s%s\n", \
172 		num, temp, \
173 		(temp & RH_PS_PRSC) ? " PRSC" : "", \
174 		(temp & RH_PS_OCIC) ? " OCIC" : "", \
175 		(temp & RH_PS_PSSC) ? " PSSC" : "", \
176 		(temp & RH_PS_PESC) ? " PESC" : "", \
177 		(temp & RH_PS_CSC) ? " CSC" : "", \
178 		\
179 		(temp & RH_PS_LSDA) ? " LSDA" : "", \
180 		(temp & RH_PS_PPS) ? " PPS" : "", \
181 		(temp & RH_PS_PRS) ? " PRS" : "", \
182 		(temp & RH_PS_POCI) ? " POCI" : "", \
183 		(temp & RH_PS_PSS) ? " PSS" : "", \
184 		\
185 		(temp & RH_PS_PES) ? " PES" : "", \
186 		(temp & RH_PS_CCS) ? " CCS" : "" \
187 		);
188 
189 
190 static void
191 ohci_dump_roothub (
192 	struct ohci_hcd *controller,
193 	int verbose,
194 	char **next,
195 	unsigned *size)
196 {
197 	u32			temp, i;
198 
199 	temp = roothub_a (controller);
200 	if (temp == ~(u32)0)
201 		return;
202 
203 	if (verbose) {
204 		ohci_dbg_sw (controller, next, size,
205 			"roothub.a %08x POTPGT=%d%s%s%s%s%s NDP=%d(%d)\n", temp,
206 			((temp & RH_A_POTPGT) >> 24) & 0xff,
207 			(temp & RH_A_NOCP) ? " NOCP" : "",
208 			(temp & RH_A_OCPM) ? " OCPM" : "",
209 			(temp & RH_A_DT) ? " DT" : "",
210 			(temp & RH_A_NPS) ? " NPS" : "",
211 			(temp & RH_A_PSM) ? " PSM" : "",
212 			(temp & RH_A_NDP), controller->num_ports
213 			);
214 		temp = roothub_b (controller);
215 		ohci_dbg_sw (controller, next, size,
216 			"roothub.b %08x PPCM=%04x DR=%04x\n",
217 			temp,
218 			(temp & RH_B_PPCM) >> 16,
219 			(temp & RH_B_DR)
220 			);
221 		temp = roothub_status (controller);
222 		ohci_dbg_sw (controller, next, size,
223 			"roothub.status %08x%s%s%s%s%s%s\n",
224 			temp,
225 			(temp & RH_HS_CRWE) ? " CRWE" : "",
226 			(temp & RH_HS_OCIC) ? " OCIC" : "",
227 			(temp & RH_HS_LPSC) ? " LPSC" : "",
228 			(temp & RH_HS_DRWE) ? " DRWE" : "",
229 			(temp & RH_HS_OCI) ? " OCI" : "",
230 			(temp & RH_HS_LPS) ? " LPS" : ""
231 			);
232 	}
233 
234 	for (i = 0; i < controller->num_ports; i++) {
235 		temp = roothub_portstatus (controller, i);
236 		dbg_port_sw (controller, i, temp, next, size);
237 	}
238 }
239 
240 static void ohci_dump(struct ohci_hcd *controller)
241 {
242 	ohci_dbg (controller, "OHCI controller state\n");
243 
244 	// dumps some of the state we know about
245 	ohci_dump_status (controller, NULL, NULL);
246 	if (controller->hcca)
247 		ohci_dbg (controller,
248 			"hcca frame #%04x\n", ohci_frame_no(controller));
249 	ohci_dump_roothub (controller, 1, NULL, NULL);
250 }
251 
252 static const char data0 [] = "DATA0";
253 static const char data1 [] = "DATA1";
254 
255 static void ohci_dump_td (const struct ohci_hcd *ohci, const char *label,
256 		const struct td *td)
257 {
258 	u32	tmp = hc32_to_cpup (ohci, &td->hwINFO);
259 
260 	ohci_dbg (ohci, "%s td %p%s; urb %p index %d; hw next td %08x\n",
261 		label, td,
262 		(tmp & TD_DONE) ? " (DONE)" : "",
263 		td->urb, td->index,
264 		hc32_to_cpup (ohci, &td->hwNextTD));
265 	if ((tmp & TD_ISO) == 0) {
266 		const char	*toggle, *pid;
267 		u32	cbp, be;
268 
269 		switch (tmp & TD_T) {
270 		case TD_T_DATA0: toggle = data0; break;
271 		case TD_T_DATA1: toggle = data1; break;
272 		case TD_T_TOGGLE: toggle = "(CARRY)"; break;
273 		default: toggle = "(?)"; break;
274 		}
275 		switch (tmp & TD_DP) {
276 		case TD_DP_SETUP: pid = "SETUP"; break;
277 		case TD_DP_IN: pid = "IN"; break;
278 		case TD_DP_OUT: pid = "OUT"; break;
279 		default: pid = "(bad pid)"; break;
280 		}
281 		ohci_dbg (ohci, "     info %08x CC=%x %s DI=%d %s %s\n", tmp,
282 			TD_CC_GET(tmp), /* EC, */ toggle,
283 			(tmp & TD_DI) >> 21, pid,
284 			(tmp & TD_R) ? "R" : "");
285 		cbp = hc32_to_cpup (ohci, &td->hwCBP);
286 		be = hc32_to_cpup (ohci, &td->hwBE);
287 		ohci_dbg (ohci, "     cbp %08x be %08x (len %d)\n", cbp, be,
288 			cbp ? (be + 1 - cbp) : 0);
289 	} else {
290 		unsigned	i;
291 		ohci_dbg (ohci, "  info %08x CC=%x FC=%d DI=%d SF=%04x\n", tmp,
292 			TD_CC_GET(tmp),
293 			(tmp >> 24) & 0x07,
294 			(tmp & TD_DI) >> 21,
295 			tmp & 0x0000ffff);
296 		ohci_dbg (ohci, "  bp0 %08x be %08x\n",
297 			hc32_to_cpup (ohci, &td->hwCBP) & ~0x0fff,
298 			hc32_to_cpup (ohci, &td->hwBE));
299 		for (i = 0; i < MAXPSW; i++) {
300 			u16	psw = ohci_hwPSW (ohci, td, i);
301 			int	cc = (psw >> 12) & 0x0f;
302 			ohci_dbg (ohci, "    psw [%d] = %2x, CC=%x %s=%d\n", i,
303 				psw, cc,
304 				(cc >= 0x0e) ? "OFFSET" : "SIZE",
305 				psw & 0x0fff);
306 		}
307 	}
308 }
309 
310 /* caller MUST own hcd spinlock if verbose is set! */
311 static void __maybe_unused
312 ohci_dump_ed (const struct ohci_hcd *ohci, const char *label,
313 		const struct ed *ed, int verbose)
314 {
315 	u32	tmp = hc32_to_cpu (ohci, ed->hwINFO);
316 	char	*type = "";
317 
318 	ohci_dbg (ohci, "%s, ed %p state 0x%x type %s; next ed %08x\n",
319 		label,
320 		ed, ed->state, edstring (ed->type),
321 		hc32_to_cpup (ohci, &ed->hwNextED));
322 	switch (tmp & (ED_IN|ED_OUT)) {
323 	case ED_OUT: type = "-OUT"; break;
324 	case ED_IN: type = "-IN"; break;
325 	/* else from TDs ... control */
326 	}
327 	ohci_dbg (ohci,
328 		"  info %08x MAX=%d%s%s%s%s EP=%d%s DEV=%d\n", tmp,
329 		0x03ff & (tmp >> 16),
330 		(tmp & ED_DEQUEUE) ? " DQ" : "",
331 		(tmp & ED_ISO) ? " ISO" : "",
332 		(tmp & ED_SKIP) ? " SKIP" : "",
333 		(tmp & ED_LOWSPEED) ? " LOW" : "",
334 		0x000f & (tmp >> 7),
335 		type,
336 		0x007f & tmp);
337 	tmp = hc32_to_cpup (ohci, &ed->hwHeadP);
338 	ohci_dbg (ohci, "  tds: head %08x %s%s tail %08x%s\n",
339 		tmp,
340 		(tmp & ED_C) ? data1 : data0,
341 		(tmp & ED_H) ? " HALT" : "",
342 		hc32_to_cpup (ohci, &ed->hwTailP),
343 		verbose ? "" : " (not listing)");
344 	if (verbose) {
345 		struct list_head	*tmp;
346 
347 		/* use ed->td_list because HC concurrently modifies
348 		 * hwNextTD as it accumulates ed_donelist.
349 		 */
350 		list_for_each (tmp, &ed->td_list) {
351 			struct td		*td;
352 			td = list_entry (tmp, struct td, td_list);
353 			ohci_dump_td (ohci, "  ->", td);
354 		}
355 	}
356 }
357 
358 /*-------------------------------------------------------------------------*/
359 
360 static int debug_async_open(struct inode *, struct file *);
361 static int debug_periodic_open(struct inode *, struct file *);
362 static int debug_registers_open(struct inode *, struct file *);
363 static int debug_async_open(struct inode *, struct file *);
364 static ssize_t debug_output(struct file*, char __user*, size_t, loff_t*);
365 static int debug_close(struct inode *, struct file *);
366 
367 static const struct file_operations debug_async_fops = {
368 	.owner		= THIS_MODULE,
369 	.open		= debug_async_open,
370 	.read		= debug_output,
371 	.release	= debug_close,
372 	.llseek		= default_llseek,
373 };
374 static const struct file_operations debug_periodic_fops = {
375 	.owner		= THIS_MODULE,
376 	.open		= debug_periodic_open,
377 	.read		= debug_output,
378 	.release	= debug_close,
379 	.llseek		= default_llseek,
380 };
381 static const struct file_operations debug_registers_fops = {
382 	.owner		= THIS_MODULE,
383 	.open		= debug_registers_open,
384 	.read		= debug_output,
385 	.release	= debug_close,
386 	.llseek		= default_llseek,
387 };
388 
389 static struct dentry *ohci_debug_root;
390 
391 struct debug_buffer {
392 	ssize_t (*fill_func)(struct debug_buffer *);	/* fill method */
393 	struct ohci_hcd *ohci;
394 	struct mutex mutex;	/* protect filling of buffer */
395 	size_t count;		/* number of characters filled into buffer */
396 	char *page;
397 };
398 
399 static ssize_t
400 show_list (struct ohci_hcd *ohci, char *buf, size_t count, struct ed *ed)
401 {
402 	unsigned		temp, size = count;
403 
404 	if (!ed)
405 		return 0;
406 
407 	/* print first --> last */
408 	while (ed->ed_prev)
409 		ed = ed->ed_prev;
410 
411 	/* dump a snapshot of the bulk or control schedule */
412 	while (ed) {
413 		u32		info = hc32_to_cpu (ohci, ed->hwINFO);
414 		u32		headp = hc32_to_cpu (ohci, ed->hwHeadP);
415 		struct list_head *entry;
416 		struct td	*td;
417 
418 		temp = scnprintf (buf, size,
419 			"ed/%p %cs dev%d ep%d%s max %d %08x%s%s %s",
420 			ed,
421 			(info & ED_LOWSPEED) ? 'l' : 'f',
422 			info & 0x7f,
423 			(info >> 7) & 0xf,
424 			(info & ED_IN) ? "in" : "out",
425 			0x03ff & (info >> 16),
426 			info,
427 			(info & ED_SKIP) ? " s" : "",
428 			(headp & ED_H) ? " H" : "",
429 			(headp & ED_C) ? data1 : data0);
430 		size -= temp;
431 		buf += temp;
432 
433 		list_for_each (entry, &ed->td_list) {
434 			u32		cbp, be;
435 
436 			td = list_entry (entry, struct td, td_list);
437 			info = hc32_to_cpup (ohci, &td->hwINFO);
438 			cbp = hc32_to_cpup (ohci, &td->hwCBP);
439 			be = hc32_to_cpup (ohci, &td->hwBE);
440 			temp = scnprintf (buf, size,
441 					"\n\ttd %p %s %d cc=%x urb %p (%08x)",
442 					td,
443 					({ char *pid;
444 					switch (info & TD_DP) {
445 					case TD_DP_SETUP: pid = "setup"; break;
446 					case TD_DP_IN: pid = "in"; break;
447 					case TD_DP_OUT: pid = "out"; break;
448 					default: pid = "(?)"; break;
449 					 } pid;}),
450 					cbp ? (be + 1 - cbp) : 0,
451 					TD_CC_GET (info), td->urb, info);
452 			size -= temp;
453 			buf += temp;
454 		}
455 
456 		temp = scnprintf (buf, size, "\n");
457 		size -= temp;
458 		buf += temp;
459 
460 		ed = ed->ed_next;
461 	}
462 	return count - size;
463 }
464 
465 static ssize_t fill_async_buffer(struct debug_buffer *buf)
466 {
467 	struct ohci_hcd		*ohci;
468 	size_t			temp, size;
469 	unsigned long		flags;
470 
471 	ohci = buf->ohci;
472 	size = PAGE_SIZE;
473 
474 	/* display control and bulk lists together, for simplicity */
475 	spin_lock_irqsave (&ohci->lock, flags);
476 	temp = show_list(ohci, buf->page, size, ohci->ed_controltail);
477 	temp += show_list(ohci, buf->page + temp, size - temp,
478 			  ohci->ed_bulktail);
479 	spin_unlock_irqrestore (&ohci->lock, flags);
480 
481 	return temp;
482 }
483 
484 #define DBG_SCHED_LIMIT 64
485 
486 static ssize_t fill_periodic_buffer(struct debug_buffer *buf)
487 {
488 	struct ohci_hcd		*ohci;
489 	struct ed		**seen, *ed;
490 	unsigned long		flags;
491 	unsigned		temp, size, seen_count;
492 	char			*next;
493 	unsigned		i;
494 
495 	seen = kmalloc_array(DBG_SCHED_LIMIT, sizeof(*seen), GFP_ATOMIC);
496 	if (!seen)
497 		return 0;
498 	seen_count = 0;
499 
500 	ohci = buf->ohci;
501 	next = buf->page;
502 	size = PAGE_SIZE;
503 
504 	temp = scnprintf (next, size, "size = %d\n", NUM_INTS);
505 	size -= temp;
506 	next += temp;
507 
508 	/* dump a snapshot of the periodic schedule (and load) */
509 	spin_lock_irqsave (&ohci->lock, flags);
510 	for (i = 0; i < NUM_INTS; i++) {
511 		ed = ohci->periodic[i];
512 		if (!ed)
513 			continue;
514 
515 		temp = scnprintf (next, size, "%2d [%3d]:", i, ohci->load [i]);
516 		size -= temp;
517 		next += temp;
518 
519 		do {
520 			temp = scnprintf (next, size, " ed%d/%p",
521 				ed->interval, ed);
522 			size -= temp;
523 			next += temp;
524 			for (temp = 0; temp < seen_count; temp++) {
525 				if (seen [temp] == ed)
526 					break;
527 			}
528 
529 			/* show more info the first time around */
530 			if (temp == seen_count) {
531 				u32	info = hc32_to_cpu (ohci, ed->hwINFO);
532 				struct list_head	*entry;
533 				unsigned		qlen = 0;
534 
535 				/* qlen measured here in TDs, not urbs */
536 				list_for_each (entry, &ed->td_list)
537 					qlen++;
538 
539 				temp = scnprintf (next, size,
540 					" (%cs dev%d ep%d%s-%s qlen %u"
541 					" max %d %08x%s%s)",
542 					(info & ED_LOWSPEED) ? 'l' : 'f',
543 					info & 0x7f,
544 					(info >> 7) & 0xf,
545 					(info & ED_IN) ? "in" : "out",
546 					(info & ED_ISO) ? "iso" : "int",
547 					qlen,
548 					0x03ff & (info >> 16),
549 					info,
550 					(info & ED_SKIP) ? " K" : "",
551 					(ed->hwHeadP &
552 						cpu_to_hc32(ohci, ED_H)) ?
553 							" H" : "");
554 				size -= temp;
555 				next += temp;
556 
557 				if (seen_count < DBG_SCHED_LIMIT)
558 					seen [seen_count++] = ed;
559 
560 				ed = ed->ed_next;
561 
562 			} else {
563 				/* we've seen it and what's after */
564 				temp = 0;
565 				ed = NULL;
566 			}
567 
568 		} while (ed);
569 
570 		temp = scnprintf (next, size, "\n");
571 		size -= temp;
572 		next += temp;
573 	}
574 	spin_unlock_irqrestore (&ohci->lock, flags);
575 	kfree (seen);
576 
577 	return PAGE_SIZE - size;
578 }
579 #undef DBG_SCHED_LIMIT
580 
581 static ssize_t fill_registers_buffer(struct debug_buffer *buf)
582 {
583 	struct usb_hcd		*hcd;
584 	struct ohci_hcd		*ohci;
585 	struct ohci_regs __iomem *regs;
586 	unsigned long		flags;
587 	unsigned		temp, size;
588 	char			*next;
589 	u32			rdata;
590 
591 	ohci = buf->ohci;
592 	hcd = ohci_to_hcd(ohci);
593 	regs = ohci->regs;
594 	next = buf->page;
595 	size = PAGE_SIZE;
596 
597 	spin_lock_irqsave (&ohci->lock, flags);
598 
599 	/* dump driver info, then registers in spec order */
600 
601 	ohci_dbg_nosw(ohci, &next, &size,
602 		"bus %s, device %s\n"
603 		"%s\n"
604 		"%s\n",
605 		hcd->self.controller->bus->name,
606 		dev_name(hcd->self.controller),
607 		hcd->product_desc,
608 		hcd_name);
609 
610 	if (!HCD_HW_ACCESSIBLE(hcd)) {
611 		size -= scnprintf (next, size,
612 			"SUSPENDED (no register access)\n");
613 		goto done;
614 	}
615 
616 	ohci_dump_status(ohci, &next, &size);
617 
618 	/* hcca */
619 	if (ohci->hcca)
620 		ohci_dbg_nosw(ohci, &next, &size,
621 			"hcca frame 0x%04x\n", ohci_frame_no(ohci));
622 
623 	/* other registers mostly affect frame timings */
624 	rdata = ohci_readl (ohci, &regs->fminterval);
625 	temp = scnprintf (next, size,
626 			"fmintvl 0x%08x %sFSMPS=0x%04x FI=0x%04x\n",
627 			rdata, (rdata >> 31) ? "FIT " : "",
628 			(rdata >> 16) & 0xefff, rdata & 0xffff);
629 	size -= temp;
630 	next += temp;
631 
632 	rdata = ohci_readl (ohci, &regs->fmremaining);
633 	temp = scnprintf (next, size, "fmremaining 0x%08x %sFR=0x%04x\n",
634 			rdata, (rdata >> 31) ? "FRT " : "",
635 			rdata & 0x3fff);
636 	size -= temp;
637 	next += temp;
638 
639 	rdata = ohci_readl (ohci, &regs->periodicstart);
640 	temp = scnprintf (next, size, "periodicstart 0x%04x\n",
641 			rdata & 0x3fff);
642 	size -= temp;
643 	next += temp;
644 
645 	rdata = ohci_readl (ohci, &regs->lsthresh);
646 	temp = scnprintf (next, size, "lsthresh 0x%04x\n",
647 			rdata & 0x3fff);
648 	size -= temp;
649 	next += temp;
650 
651 	temp = scnprintf (next, size, "hub poll timer %s\n",
652 			HCD_POLL_RH(ohci_to_hcd(ohci)) ? "ON" : "off");
653 	size -= temp;
654 	next += temp;
655 
656 	/* roothub */
657 	ohci_dump_roothub (ohci, 1, &next, &size);
658 
659 done:
660 	spin_unlock_irqrestore (&ohci->lock, flags);
661 
662 	return PAGE_SIZE - size;
663 }
664 
665 static struct debug_buffer *alloc_buffer(struct ohci_hcd *ohci,
666 				ssize_t (*fill_func)(struct debug_buffer *))
667 {
668 	struct debug_buffer *buf;
669 
670 	buf = kzalloc(sizeof(struct debug_buffer), GFP_KERNEL);
671 
672 	if (buf) {
673 		buf->ohci = ohci;
674 		buf->fill_func = fill_func;
675 		mutex_init(&buf->mutex);
676 	}
677 
678 	return buf;
679 }
680 
681 static int fill_buffer(struct debug_buffer *buf)
682 {
683 	int ret = 0;
684 
685 	if (!buf->page)
686 		buf->page = (char *)get_zeroed_page(GFP_KERNEL);
687 
688 	if (!buf->page) {
689 		ret = -ENOMEM;
690 		goto out;
691 	}
692 
693 	ret = buf->fill_func(buf);
694 
695 	if (ret >= 0) {
696 		buf->count = ret;
697 		ret = 0;
698 	}
699 
700 out:
701 	return ret;
702 }
703 
704 static ssize_t debug_output(struct file *file, char __user *user_buf,
705 			size_t len, loff_t *offset)
706 {
707 	struct debug_buffer *buf = file->private_data;
708 	int ret = 0;
709 
710 	mutex_lock(&buf->mutex);
711 	if (buf->count == 0) {
712 		ret = fill_buffer(buf);
713 		if (ret != 0) {
714 			mutex_unlock(&buf->mutex);
715 			goto out;
716 		}
717 	}
718 	mutex_unlock(&buf->mutex);
719 
720 	ret = simple_read_from_buffer(user_buf, len, offset,
721 				      buf->page, buf->count);
722 
723 out:
724 	return ret;
725 
726 }
727 
728 static int debug_close(struct inode *inode, struct file *file)
729 {
730 	struct debug_buffer *buf = file->private_data;
731 
732 	if (buf) {
733 		if (buf->page)
734 			free_page((unsigned long)buf->page);
735 		kfree(buf);
736 	}
737 
738 	return 0;
739 }
740 static int debug_async_open(struct inode *inode, struct file *file)
741 {
742 	file->private_data = alloc_buffer(inode->i_private, fill_async_buffer);
743 
744 	return file->private_data ? 0 : -ENOMEM;
745 }
746 
747 static int debug_periodic_open(struct inode *inode, struct file *file)
748 {
749 	file->private_data = alloc_buffer(inode->i_private,
750 					  fill_periodic_buffer);
751 
752 	return file->private_data ? 0 : -ENOMEM;
753 }
754 
755 static int debug_registers_open(struct inode *inode, struct file *file)
756 {
757 	file->private_data = alloc_buffer(inode->i_private,
758 					  fill_registers_buffer);
759 
760 	return file->private_data ? 0 : -ENOMEM;
761 }
762 static inline void create_debug_files (struct ohci_hcd *ohci)
763 {
764 	struct usb_bus *bus = &ohci_to_hcd(ohci)->self;
765 	struct dentry *root;
766 
767 	root = debugfs_create_dir(bus->bus_name, ohci_debug_root);
768 	ohci->debug_dir = root;
769 
770 	debugfs_create_file("async", S_IRUGO, root, ohci, &debug_async_fops);
771 	debugfs_create_file("periodic", S_IRUGO, root, ohci,
772 			    &debug_periodic_fops);
773 	debugfs_create_file("registers", S_IRUGO, root, ohci,
774 			    &debug_registers_fops);
775 
776 	ohci_dbg (ohci, "created debug files\n");
777 }
778 
779 static inline void remove_debug_files (struct ohci_hcd *ohci)
780 {
781 	debugfs_remove_recursive(ohci->debug_dir);
782 }
783 
784 /*-------------------------------------------------------------------------*/
785 
786