xref: /freebsd/sys/dev/wbwd/wbwd.c (revision 2e3f49888ec8851bafb22011533217487764fdb0)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2011 Sandvine Incorporated ULC.
5  * Copyright (c) 2012 iXsystems, Inc.
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 /*
30  * Support for Winbond watchdog.
31  *
32  * With minor abstractions it might be possible to add support for other
33  * different Winbond Super I/O chips as well.  Winbond seems to have four
34  * different types of chips, four different ways to get into extended config
35  * mode.
36  *
37  * Note: there is no serialization between the debugging sysctl handlers and
38  * the watchdog functions and possibly others poking the registers at the same
39  * time.  For that at least possibly interfering sysctls are hidden by default.
40  */
41 
42 #include <sys/param.h>
43 #include <sys/kernel.h>
44 #include <sys/systm.h>
45 #include <sys/bus.h>
46 #include <sys/eventhandler.h>
47 #include <sys/module.h>
48 #include <sys/sbuf.h>
49 #include <sys/sysctl.h>
50 #include <sys/watchdog.h>
51 
52 #include <dev/superio/superio.h>
53 
54 #include <machine/bus.h>
55 #include <machine/resource.h>
56 
57 /*
58  * Global registers.
59  */
60 #define	WB_DEVICE_ID_REG	0x20	/* Device ID */
61 #define	WB_DEVICE_REV_REG	0x21	/* Device revision */
62 #define	WB_CR26			0x26	/* Bit6: HEFRAS (base port selector) */
63 
64 /* LDN selection. */
65 #define	WB_LDN_REG		0x07
66 #define	WB_LDN_REG_LDN8		0x08	/* GPIO 2, Watchdog */
67 
68 /*
69  * LDN8 (GPIO 2, Watchdog) specific registers and options.
70  */
71 /* CR30: LDN8 activation control. */
72 #define	WB_LDN8_CR30		0x30
73 #define	WB_LDN8_CR30_ACTIVE	0x01	/* 1: LD active */
74 
75 /* CRF5: Watchdog scale, P20. Mapped to reg_1. */
76 #define	WB_LDN8_CRF5		0xF5
77 #define	WB_LDN8_CRF5_SCALE	0x08	/* 0: 1s, 1: 60s */
78 #define	WB_LDN8_CRF5_KEYB_P20	0x04	/* 1: keyb P20 forces timeout */
79 #define	WB_LDN8_CRF5_KBRST	0x02	/* 1: timeout causes pin60 kbd reset */
80 
81 /* CRF6: Watchdog Timeout (0 == off). Mapped to reg_timeout. */
82 #define	WB_LDN8_CRF6		0xF6
83 
84 /* CRF7: Watchdog mouse, keyb, force, .. Mapped to reg_2. */
85 #define	WB_LDN8_CRF7		0xF7
86 #define	WB_LDN8_CRF7_MOUSE	0x80	/* 1: mouse irq resets wd timer */
87 #define	WB_LDN8_CRF7_KEYB	0x40	/* 1: keyb irq resets wd timer */
88 #define	WB_LDN8_CRF7_FORCE	0x20	/* 1: force timeout (self-clear) */
89 #define	WB_LDN8_CRF7_TS		0x10	/* 0: counting, 1: fired */
90 #define	WB_LDN8_CRF7_IRQS	0x0f	/* irq source for watchdog, 2 == SMI */
91 
92 enum chips { w83627hf, w83627s, w83697hf, w83697ug, w83637hf, w83627thf,
93 	     w83687thf, w83627ehf, w83627dhg, w83627uhg, w83667hg,
94 	     w83627dhg_p, w83667hg_b, nct6775, nct6776, nct6779, nct6791,
95 	     nct6792, nct6793, nct6795, nct6102 };
96 
97 struct wb_softc {
98 	device_t		dev;
99 	eventhandler_tag	ev_tag;
100 	enum chips		chip;
101 	uint8_t			ctl_reg;
102 	uint8_t			time_reg;
103 	uint8_t			csr_reg;
104 	int			debug_verbose;
105 
106 	/*
107 	 * Special feature to let the watchdog fire at a different
108 	 * timeout as set by watchdog(4) but still use that API to
109 	 * re-load it periodically.
110 	 */
111 	unsigned int		timeout_override;
112 
113 	/*
114 	 * Space to save current state temporary and for sysctls.
115 	 * We want to know the timeout value and usually need two
116 	 * additional registers for options. Do not name them by
117 	 * register as these might be different by chip.
118 	 */
119 	uint8_t			reg_timeout;
120 	uint8_t			reg_1;
121 	uint8_t			reg_2;
122 };
123 
124 struct winbond_vendor_device_id {
125 	uint8_t			device_id;
126 	enum chips		chip;
127 	const char *		descr;
128 } wb_devs[] = {
129 	{
130 		.device_id	= 0x52,
131 		.chip		= w83627hf,
132 		.descr		= "Winbond 83627HF/F/HG/G",
133 	},
134 	{
135 		.device_id	= 0x59,
136 		.chip		= w83627s,
137 		.descr		= "Winbond 83627S",
138 	},
139 	{
140 		.device_id	= 0x60,
141 		.chip		= w83697hf,
142 		.descr		= "Winbond 83697HF",
143 	},
144 	{
145 		.device_id	= 0x68,
146 		.chip		= w83697ug,
147 		.descr		= "Winbond 83697UG",
148 	},
149 	{
150 		.device_id	= 0x70,
151 		.chip		= w83637hf,
152 		.descr		= "Winbond 83637HF",
153 	},
154 	{
155 		.device_id	= 0x82,
156 		.chip		= w83627thf,
157 		.descr		= "Winbond 83627THF",
158 	},
159 	{
160 		.device_id	= 0x85,
161 		.chip		= w83687thf,
162 		.descr		= "Winbond 83687THF",
163 	},
164 	{
165 		.device_id	= 0x88,
166 		.chip		= w83627ehf,
167 		.descr		= "Winbond 83627EHF",
168 	},
169 	{
170 		.device_id	= 0xa0,
171 		.chip		= w83627dhg,
172 		.descr		= "Winbond 83627DHG",
173 	},
174 	{
175 		.device_id	= 0xa2,
176 		.chip		= w83627uhg,
177 		.descr		= "Winbond 83627UHG",
178 	},
179 	{
180 		.device_id	= 0xa5,
181 		.chip		= w83667hg,
182 		.descr		= "Winbond 83667HG",
183 	},
184 	{
185 		.device_id	= 0xb0,
186 		.chip		= w83627dhg_p,
187 		.descr		= "Winbond 83627DHG-P",
188 	},
189 	{
190 		.device_id	= 0xb3,
191 		.chip		= w83667hg_b,
192 		.descr		= "Winbond 83667HG-B",
193 	},
194 	{
195 		.device_id	= 0xb4,
196 		.chip		= nct6775,
197 		.descr		= "Nuvoton NCT6775",
198 	},
199 	{
200 		.device_id	= 0xc3,
201 		.chip		= nct6776,
202 		.descr		= "Nuvoton NCT6776",
203 	},
204 	{
205 		.device_id	= 0xc4,
206 		.chip		= nct6102,
207 		.descr		= "Nuvoton NCT6102",
208 	},
209 	{
210 		.device_id	= 0xc5,
211 		.chip		= nct6779,
212 		.descr		= "Nuvoton NCT6779",
213 	},
214 	{
215 		.device_id	= 0xc8,
216 		.chip		= nct6791,
217 		.descr		= "Nuvoton NCT6791",
218 	},
219 	{
220 		.device_id	= 0xc9,
221 		.chip		= nct6792,
222 		.descr		= "Nuvoton NCT6792",
223 	},
224 	{
225 		.device_id	= 0xd1,
226 		.chip		= nct6793,
227 		.descr		= "Nuvoton NCT6793",
228 	},
229 	{
230 		.device_id	= 0xd3,
231 		.chip		= nct6795,
232 		.descr		= "Nuvoton NCT6795",
233 	},
234 };
235 
236 /*
237  * Return the watchdog related registers as we last read them.  This will
238  * usually not give the current timeout or state on whether the watchdog
239  * fired.
240  */
241 static int
242 sysctl_wb_debug(SYSCTL_HANDLER_ARGS)
243 {
244 	struct wb_softc *sc;
245 	struct sbuf sb;
246 	int error;
247 
248 	sc = arg1;
249 
250 	sbuf_new_for_sysctl(&sb, NULL, 64, req);
251 
252 	sbuf_printf(&sb, "LDN8 (GPIO2, Watchdog): ");
253 	sbuf_printf(&sb, "CR%02X 0x%02x ", sc->ctl_reg, sc->reg_1);
254 	sbuf_printf(&sb, "CR%02X 0x%02x ", sc->time_reg, sc->reg_timeout);
255 	sbuf_printf(&sb, "CR%02X 0x%02x", sc->csr_reg, sc->reg_2);
256 
257 	error = sbuf_finish(&sb);
258 	sbuf_delete(&sb);
259 	return (error);
260 }
261 
262 /*
263  * Read the current values before returning them.  Given this might poke
264  * the registers the same time as the watchdog, this sysctl handler should
265  * be marked CTLFLAG_SKIP to not show up by default.
266  */
267 static int
268 sysctl_wb_debug_current(SYSCTL_HANDLER_ARGS)
269 {
270 	struct wb_softc *sc;
271 
272 	sc = arg1;
273 
274 	sc->reg_1 = superio_read(sc->dev, sc->ctl_reg);
275 	sc->reg_timeout = superio_read(sc->dev, sc->time_reg);
276 	sc->reg_2 = superio_read(sc->dev, sc->csr_reg);
277 
278 	return (sysctl_wb_debug(oidp, arg1, arg2, req));
279 }
280 
281 /*
282  * Sysctl handlers to force a watchdog timeout or to test the NMI functionality
283  * works as expetced.
284  * For testing we could set a test_nmi flag in the softc that, in case of NMI, a
285  * callback function from trap.c could check whether we fired and not report the
286  * timeout but clear the flag for the sysctl again.  This is interesting given a
287  * lot of boards have jumpers to change the action on watchdog timeout or
288  * disable the watchdog completely.
289  * XXX-BZ notyet: currently no general infrastructure exists to do this.
290  */
291 static int
292 sysctl_wb_force_test_nmi(SYSCTL_HANDLER_ARGS)
293 {
294 	struct wb_softc *sc;
295 	int error, val;
296 
297 	sc = arg1;
298 
299 #ifdef notyet
300 	val = sc->test_nmi;
301 #else
302 	val = 0;
303 #endif
304 	error = sysctl_handle_int(oidp, &val, 0, req);
305         if (error || !req->newptr)
306                 return (error);
307 
308 #ifdef notyet
309 	int test = arg2;
310 
311 	/* Manually clear the test for a value of 0 and do nothing else. */
312 	if (test && val == 0) {
313 		sc->test_nmi = 0;
314 		return (0);
315 	}
316 
317 	/*
318 	 * If we are testing the NMI functionality, set the flag before
319 	 * forcing the timeout.
320 	 */
321 	if (test)
322 		sc->test_nmi = 1;
323 #endif
324 
325 	/* Force watchdog to fire. */
326 	sc->reg_2 = superio_read(sc->dev, sc->csr_reg);
327 	sc->reg_2 |= WB_LDN8_CRF7_FORCE;
328 	superio_write(sc->dev, sc->csr_reg, sc->reg_2);
329 
330 	return (0);
331 }
332 
333 /*
334  * Print current watchdog state.
335  *
336  * Note: it is the responsibility of the caller to update the registers
337  * upfront.
338  */
339 static void
340 wb_print_state(struct wb_softc *sc, const char *msg)
341 {
342 
343 	device_printf(sc->dev, "%s%sWatchdog %sabled. %s"
344 	    "Scaling by %ds, timer at %d (%s=%ds%s). "
345 	    "CR%02X 0x%02x CR%02X 0x%02x\n",
346 	    (msg != NULL) ? msg : "", (msg != NULL) ? ": " : "",
347 	    (sc->reg_timeout > 0x00) ? "en" : "dis",
348 	    (sc->reg_2 & WB_LDN8_CRF7_TS) ? "Watchdog fired. " : "",
349 	    (sc->reg_1 & WB_LDN8_CRF5_SCALE) ? 60 : 1,
350 	    sc->reg_timeout,
351 	    (sc->reg_timeout > 0x00) ? "<" : "",
352 	    sc->reg_timeout * ((sc->reg_1 & WB_LDN8_CRF5_SCALE) ? 60 : 1),
353 	    (sc->reg_timeout > 0x00) ? " left" : "",
354 	    sc->ctl_reg, sc->reg_1, sc->csr_reg, sc->reg_2);
355 }
356 
357 /*
358  * (Re)load the watchdog counter depending on timeout.  A timeout of 0 will
359  * disable the watchdog.
360  */
361 static int
362 wb_set_watchdog(struct wb_softc *sc, unsigned int timeout)
363 {
364 
365 	if (timeout != 0) {
366 		/*
367 		 * In case an override is set, let it override.  It may lead
368 		 * to strange results as we do not check the input of the sysctl.
369 		 */
370 		if (sc->timeout_override > 0)
371 			timeout = sc->timeout_override;
372 
373 		/* Make sure we support the requested timeout. */
374 		if (timeout > 255 * 60)
375 			return (EINVAL);
376 	}
377 
378 	if (sc->debug_verbose)
379 		wb_print_state(sc, "Before watchdog counter (re)load");
380 
381 	if (timeout == 0) {
382 		/* Disable watchdog. */
383 		sc->reg_timeout = 0;
384 		superio_write(sc->dev, sc->time_reg, sc->reg_timeout);
385 
386 	} else {
387 		/* Read current scaling factor. */
388 		sc->reg_1 = superio_read(sc->dev, sc->ctl_reg);
389 
390 		if (timeout > 255) {
391 			/* Set scaling factor to 60s. */
392 			sc->reg_1 |= WB_LDN8_CRF5_SCALE;
393 			sc->reg_timeout = (timeout / 60);
394 			if (timeout % 60)
395 				sc->reg_timeout++;
396 		} else {
397 			/* Set scaling factor to 1s. */
398 			sc->reg_1 &= ~WB_LDN8_CRF5_SCALE;
399 			sc->reg_timeout = timeout;
400 		}
401 
402 		/* In case we fired before we need to clear to fire again. */
403 		sc->reg_2 = superio_read(sc->dev, sc->csr_reg);
404 		if (sc->reg_2 & WB_LDN8_CRF7_TS) {
405 			sc->reg_2 &= ~WB_LDN8_CRF7_TS;
406 			superio_write(sc->dev, sc->csr_reg, sc->reg_2);
407 		}
408 
409 		/* Write back scaling factor. */
410 		superio_write(sc->dev, sc->ctl_reg, sc->reg_1);
411 
412 		/* Set timer and arm/reset the watchdog. */
413 		superio_write(sc->dev, sc->time_reg, sc->reg_timeout);
414 	}
415 
416 	if (sc->debug_verbose)
417 		wb_print_state(sc, "After watchdog counter (re)load");
418 	return (0);
419 }
420 
421 /*
422  * watchdog(9) EVENTHANDLER function implementation to (re)load the counter
423  * with the given timeout or disable the watchdog.
424  */
425 static void
426 wb_watchdog_fn(void *private, u_int cmd, int *error)
427 {
428 	struct wb_softc *sc;
429 	unsigned int timeout;
430 	int e;
431 
432 	sc = private;
433 	KASSERT(sc != NULL, ("%s: watchdog handler function called without "
434 	    "softc.", __func__));
435 
436 	cmd &= WD_INTERVAL;
437 	if (cmd > 0 && cmd <= 63) {
438 		/* Reset (and arm) watchdog. */
439 		timeout = ((uint64_t)1 << cmd) / 1000000000;
440 		if (timeout == 0)
441 			timeout = 1;
442 		e = wb_set_watchdog(sc, timeout);
443 		if (e == 0) {
444 			if (error != NULL)
445 				*error = 0;
446 		} else {
447 			/* On error, try to make sure the WD is disabled. */
448 			wb_set_watchdog(sc, 0);
449 		}
450 
451 	} else {
452 		/* Disable watchdog. */
453 		e = wb_set_watchdog(sc, 0);
454 		if (e != 0 && cmd == 0 && error != NULL) {
455 			/* Failed to disable watchdog. */
456 			*error = EOPNOTSUPP;
457 		}
458 	}
459 }
460 
461 static int
462 wb_probe(device_t dev)
463 {
464 	char buf[128];
465 	struct wb_softc *sc;
466 	int j;
467 	uint8_t devid;
468 	uint8_t revid;
469 
470 	if (superio_vendor(dev) != SUPERIO_VENDOR_NUVOTON)
471 		return (ENXIO);
472 	if (superio_get_type(dev) != SUPERIO_DEV_WDT)
473 		return (ENXIO);
474 
475 	sc = device_get_softc(dev);
476 	devid = superio_devid(dev) >> 8;
477 	revid = superio_revid(dev);
478 	for (j = 0; j < nitems(wb_devs); j++) {
479 		if (wb_devs[j].device_id == devid) {
480 			sc->chip = wb_devs[j].chip;
481 			snprintf(buf, sizeof(buf),
482 			    "%s (0x%02x/0x%02x) Watchdog Timer",
483 			    wb_devs[j].descr, devid, revid);
484 			device_set_desc_copy(dev, buf);
485 			return (BUS_PROBE_SPECIFIC);
486 		}
487 	}
488 	if (bootverbose) {
489 		device_printf(dev,
490 		    "unrecognized chip: devid 0x%02x, revid 0x%02x\n",
491 		    devid, revid);
492 	}
493 	return (ENXIO);
494 }
495 
496 static int
497 wb_attach(device_t dev)
498 {
499 	struct wb_softc *sc;
500 	struct sysctl_ctx_list *sctx;
501 	struct sysctl_oid *soid;
502 	unsigned long timeout;
503 	uint8_t t;
504 
505 	sc = device_get_softc(dev);
506 	sc->dev = dev;
507 
508 	/* Make sure WDT is enabled. */
509 	superio_dev_enable(dev, WB_LDN8_CR30_ACTIVE);
510 
511 	switch (sc->chip) {
512 	case w83697hf:
513 	case w83697ug:
514 		sc->ctl_reg = 0xf3;
515 		sc->time_reg = 0xf4;
516 		sc->csr_reg = 0xf7;
517 		break;
518 	case nct6102:
519 		sc->ctl_reg = 0xf0;
520 		sc->time_reg = 0xf1;
521 		sc->csr_reg = 0xf2;
522 		break;
523 	default:
524 		sc->ctl_reg = 0xf5;
525 		sc->time_reg = 0xf6;
526 		sc->csr_reg = 0xf7;
527 		break;
528 	}
529 
530 	switch (sc->chip) {
531 	case w83627hf:
532 	case w83627s:
533 		t = superio_read(dev, 0x2B) & ~0x10;
534 		superio_write(dev, 0x2B, t); /* set GPIO24 to WDT0 */
535 		break;
536 	case w83697hf:
537 		/* Set pin 119 to WDTO# mode (= CR29, WDT0) */
538 		t = superio_read(dev, 0x29) & ~0x60;
539 		t |= 0x20;
540 		superio_write(dev, 0x29, t);
541 		break;
542 	case w83697ug:
543 		/* Set pin 118 to WDTO# mode */
544 		t = superio_read(dev, 0x2b) & ~0x04;
545 		superio_write(dev, 0x2b, t);
546 		break;
547 	case w83627thf:
548 		t = (superio_read(dev, 0x2B) & ~0x08) | 0x04;
549 		superio_write(dev, 0x2B, t); /* set GPIO3 to WDT0 */
550 		break;
551 	case w83627dhg:
552 	case w83627dhg_p:
553 		t = superio_read(dev, 0x2D) & ~0x01; /* PIN77 -> WDT0# */
554 		superio_write(dev, 0x2D, t); /* set GPIO5 to WDT0 */
555 		t = superio_read(dev, sc->ctl_reg);
556 		t |= 0x02;	/* enable the WDTO# output low pulse
557 				 * to the KBRST# pin */
558 		superio_write(dev, sc->ctl_reg, t);
559 		break;
560 	case w83637hf:
561 		break;
562 	case w83687thf:
563 		t = superio_read(dev, 0x2C) & ~0x80; /* PIN47 -> WDT0# */
564 		superio_write(dev, 0x2C, t);
565 		break;
566 	case w83627ehf:
567 	case w83627uhg:
568 	case w83667hg:
569 	case w83667hg_b:
570 	case nct6775:
571 	case nct6776:
572 	case nct6779:
573 	case nct6791:
574 	case nct6792:
575 	case nct6793:
576 	case nct6795:
577 	case nct6102:
578 		/*
579 		 * These chips have a fixed WDTO# output pin (W83627UHG),
580 		 * or support more than one WDTO# output pin.
581 		 * Don't touch its configuration, and hope the BIOS
582 		 * does the right thing.
583 		 */
584 		t = superio_read(dev, sc->ctl_reg);
585 		t |= 0x02;	/* enable the WDTO# output low pulse
586 				 * to the KBRST# pin */
587 		superio_write(dev, sc->ctl_reg, t);
588 		break;
589 	default:
590 		break;
591 	}
592 
593 	/* Read the current watchdog configuration. */
594 	sc->reg_1 = superio_read(dev, sc->ctl_reg);
595 	sc->reg_timeout = superio_read(dev, sc->time_reg);
596 	sc->reg_2 = superio_read(dev, sc->csr_reg);
597 
598 	/* Print current state if bootverbose or watchdog already enabled. */
599 	if (bootverbose || (sc->reg_timeout > 0x00))
600 		wb_print_state(sc, "Before watchdog attach");
601 
602 	sc->reg_1 &= ~WB_LDN8_CRF5_KEYB_P20;
603 	sc->reg_1 |= WB_LDN8_CRF5_KBRST;
604 	superio_write(dev, sc->ctl_reg, sc->reg_1);
605 
606 	/*
607 	 * Clear a previous watchdog timeout event (if still set).
608 	 * Disable timer reset on mouse interrupts.  Leave reset on keyboard,
609 	 * since one of my boards is getting stuck in reboot without it.
610 	 */
611 	sc->reg_2 &= ~(WB_LDN8_CRF7_MOUSE|WB_LDN8_CRF7_TS);
612 	superio_write(dev, sc->csr_reg, sc->reg_2);
613 
614 	/* Read global timeout override tunable, Add per device sysctls. */
615 	if (TUNABLE_ULONG_FETCH("hw.wbwd.timeout_override", &timeout)) {
616 		if (timeout > 0)
617 			sc->timeout_override = timeout;
618 	}
619 	sctx = device_get_sysctl_ctx(dev);
620 	soid = device_get_sysctl_tree(dev);
621         SYSCTL_ADD_UINT(sctx, SYSCTL_CHILDREN(soid), OID_AUTO,
622 	    "timeout_override", CTLFLAG_RW, &sc->timeout_override, 0,
623             "Timeout in seconds overriding default watchdog timeout");
624         SYSCTL_ADD_INT(sctx, SYSCTL_CHILDREN(soid), OID_AUTO,
625 	    "debug_verbose", CTLFLAG_RW, &sc->debug_verbose, 0,
626             "Enables extra debugging information");
627         SYSCTL_ADD_PROC(sctx, SYSCTL_CHILDREN(soid), OID_AUTO, "debug",
628 	    CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, sc, 0,
629 	    sysctl_wb_debug, "A",
630             "Selected register information from last change by driver");
631         SYSCTL_ADD_PROC(sctx, SYSCTL_CHILDREN(soid), OID_AUTO, "debug_current",
632 	    CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP | CTLFLAG_MPSAFE,
633 	    sc, 0, sysctl_wb_debug_current, "A",
634 	     "Selected register information (may interfere)");
635 	SYSCTL_ADD_PROC(sctx, SYSCTL_CHILDREN(soid), OID_AUTO, "force_timeout",
636 	    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SKIP | CTLFLAG_MPSAFE, sc, 0,
637 	    sysctl_wb_force_test_nmi, "I", "Enable to force watchdog to fire.");
638 
639 	/* Register watchdog. */
640 	sc->ev_tag = EVENTHANDLER_REGISTER(watchdog_list, wb_watchdog_fn, sc,
641 	    0);
642 
643 	if (bootverbose)
644 		wb_print_state(sc, "After watchdog attach");
645 
646 	return (0);
647 }
648 
649 static int
650 wb_detach(device_t dev)
651 {
652 	struct wb_softc *sc;
653 
654 	sc = device_get_softc(dev);
655 
656 	/* Unregister and stop the watchdog if running. */
657 	if (sc->ev_tag)
658 		EVENTHANDLER_DEREGISTER(watchdog_list, sc->ev_tag);
659 	wb_set_watchdog(sc, 0);
660 
661 	/* Bus subroutines take care of sysctls already. */
662 
663 	return (0);
664 }
665 
666 static device_method_t wb_methods[] = {
667 	/* Device interface */
668 	DEVMETHOD(device_probe,		wb_probe),
669 	DEVMETHOD(device_attach,	wb_attach),
670 	DEVMETHOD(device_detach,	wb_detach),
671 
672 	DEVMETHOD_END
673 };
674 
675 static driver_t wb_driver = {
676 	"wbwd",
677 	wb_methods,
678 	sizeof(struct wb_softc)
679 };
680 
681 DRIVER_MODULE(wb, superio, wb_driver, NULL, NULL);
682 MODULE_DEPEND(wb, superio, 1, 1, 1);
683 MODULE_VERSION(wb, 1);
684