xref: /freebsd/sys/dev/wbwd/wbwd.c (revision 7ec2f6bce5d28e6662c29e63f6ab6b7ef57d98b2)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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/cdefs.h>
43 __FBSDID("$FreeBSD$");
44 
45 #include <sys/param.h>
46 #include <sys/kernel.h>
47 #include <sys/systm.h>
48 #include <sys/bus.h>
49 #include <sys/eventhandler.h>
50 #include <sys/module.h>
51 #include <sys/sbuf.h>
52 #include <sys/sysctl.h>
53 #include <sys/watchdog.h>
54 
55 #include <dev/superio/superio.h>
56 
57 #include <machine/bus.h>
58 #include <machine/resource.h>
59 
60 /*
61  * Global registers.
62  */
63 #define	WB_DEVICE_ID_REG	0x20	/* Device ID */
64 #define	WB_DEVICE_REV_REG	0x21	/* Device revision */
65 #define	WB_CR26			0x26	/* Bit6: HEFRAS (base port selector) */
66 
67 /* LDN selection. */
68 #define	WB_LDN_REG		0x07
69 #define	WB_LDN_REG_LDN8		0x08	/* GPIO 2, Watchdog */
70 
71 /*
72  * LDN8 (GPIO 2, Watchdog) specific registers and options.
73  */
74 /* CR30: LDN8 activation control. */
75 #define	WB_LDN8_CR30		0x30
76 #define	WB_LDN8_CR30_ACTIVE	0x01	/* 1: LD active */
77 
78 /* CRF5: Watchdog scale, P20. Mapped to reg_1. */
79 #define	WB_LDN8_CRF5		0xF5
80 #define	WB_LDN8_CRF5_SCALE	0x08	/* 0: 1s, 1: 60s */
81 #define	WB_LDN8_CRF5_KEYB_P20	0x04	/* 1: keyb P20 forces timeout */
82 #define	WB_LDN8_CRF5_KBRST	0x02	/* 1: timeout causes pin60 kbd reset */
83 
84 /* CRF6: Watchdog Timeout (0 == off). Mapped to reg_timeout. */
85 #define	WB_LDN8_CRF6		0xF6
86 
87 /* CRF7: Watchdog mouse, keyb, force, .. Mapped to reg_2. */
88 #define	WB_LDN8_CRF7		0xF7
89 #define	WB_LDN8_CRF7_MOUSE	0x80	/* 1: mouse irq resets wd timer */
90 #define	WB_LDN8_CRF7_KEYB	0x40	/* 1: keyb irq resets wd timer */
91 #define	WB_LDN8_CRF7_FORCE	0x20	/* 1: force timeout (self-clear) */
92 #define	WB_LDN8_CRF7_TS		0x10	/* 0: counting, 1: fired */
93 #define	WB_LDN8_CRF7_IRQS	0x0f	/* irq source for watchdog, 2 == SMI */
94 
95 enum chips { w83627hf, w83627s, w83697hf, w83697ug, w83637hf, w83627thf,
96 	     w83687thf, w83627ehf, w83627dhg, w83627uhg, w83667hg,
97 	     w83627dhg_p, w83667hg_b, nct6775, nct6776, nct6779, nct6791,
98 	     nct6792, nct6793, nct6795, nct6102 };
99 
100 struct wb_softc {
101 	device_t		dev;
102 	eventhandler_tag	ev_tag;
103 	enum chips		chip;
104 	uint8_t			ctl_reg;
105 	uint8_t			time_reg;
106 	uint8_t			csr_reg;
107 	int			debug_verbose;
108 
109 	/*
110 	 * Special feature to let the watchdog fire at a different
111 	 * timeout as set by watchdog(4) but still use that API to
112 	 * re-load it periodically.
113 	 */
114 	unsigned int		timeout_override;
115 
116 	/*
117 	 * Space to save current state temporary and for sysctls.
118 	 * We want to know the timeout value and usually need two
119 	 * additional registers for options. Do not name them by
120 	 * register as these might be different by chip.
121 	 */
122 	uint8_t			reg_timeout;
123 	uint8_t			reg_1;
124 	uint8_t			reg_2;
125 };
126 
127 struct winbond_vendor_device_id {
128 	uint8_t			device_id;
129 	enum chips		chip;
130 	const char *		descr;
131 } wb_devs[] = {
132 	{
133 		.device_id	= 0x52,
134 		.chip		= w83627hf,
135 		.descr		= "Winbond 83627HF/F/HG/G",
136 	},
137 	{
138 		.device_id	= 0x59,
139 		.chip		= w83627s,
140 		.descr		= "Winbond 83627S",
141 	},
142 	{
143 		.device_id	= 0x60,
144 		.chip		= w83697hf,
145 		.descr		= "Winbond 83697HF",
146 	},
147 	{
148 		.device_id	= 0x68,
149 		.chip		= w83697ug,
150 		.descr		= "Winbond 83697UG",
151 	},
152 	{
153 		.device_id	= 0x70,
154 		.chip		= w83637hf,
155 		.descr		= "Winbond 83637HF",
156 	},
157 	{
158 		.device_id	= 0x82,
159 		.chip		= w83627thf,
160 		.descr		= "Winbond 83627THF",
161 	},
162 	{
163 		.device_id	= 0x85,
164 		.chip		= w83687thf,
165 		.descr		= "Winbond 83687THF",
166 	},
167 	{
168 		.device_id	= 0x88,
169 		.chip		= w83627ehf,
170 		.descr		= "Winbond 83627EHF",
171 	},
172 	{
173 		.device_id	= 0xa0,
174 		.chip		= w83627dhg,
175 		.descr		= "Winbond 83627DHG",
176 	},
177 	{
178 		.device_id	= 0xa2,
179 		.chip		= w83627uhg,
180 		.descr		= "Winbond 83627UHG",
181 	},
182 	{
183 		.device_id	= 0xa5,
184 		.chip		= w83667hg,
185 		.descr		= "Winbond 83667HG",
186 	},
187 	{
188 		.device_id	= 0xb0,
189 		.chip		= w83627dhg_p,
190 		.descr		= "Winbond 83627DHG-P",
191 	},
192 	{
193 		.device_id	= 0xb3,
194 		.chip		= w83667hg_b,
195 		.descr		= "Winbond 83667HG-B",
196 	},
197 	{
198 		.device_id	= 0xb4,
199 		.chip		= nct6775,
200 		.descr		= "Nuvoton NCT6775",
201 	},
202 	{
203 		.device_id	= 0xc3,
204 		.chip		= nct6776,
205 		.descr		= "Nuvoton NCT6776",
206 	},
207 	{
208 		.device_id	= 0xc4,
209 		.chip		= nct6102,
210 		.descr		= "Nuvoton NCT6102",
211 	},
212 	{
213 		.device_id	= 0xc5,
214 		.chip		= nct6779,
215 		.descr		= "Nuvoton NCT6779",
216 	},
217 	{
218 		.device_id	= 0xc8,
219 		.chip		= nct6791,
220 		.descr		= "Nuvoton NCT6791",
221 	},
222 	{
223 		.device_id	= 0xc9,
224 		.chip		= nct6792,
225 		.descr		= "Nuvoton NCT6792",
226 	},
227 	{
228 		.device_id	= 0xd1,
229 		.chip		= nct6793,
230 		.descr		= "Nuvoton NCT6793",
231 	},
232 	{
233 		.device_id	= 0xd3,
234 		.chip		= nct6795,
235 		.descr		= "Nuvoton NCT6795",
236 	},
237 };
238 
239 /*
240  * Return the watchdog related registers as we last read them.  This will
241  * usually not give the current timeout or state on whether the watchdog
242  * fired.
243  */
244 static int
245 sysctl_wb_debug(SYSCTL_HANDLER_ARGS)
246 {
247 	struct wb_softc *sc;
248 	struct sbuf sb;
249 	int error;
250 
251 	sc = arg1;
252 
253 	sbuf_new_for_sysctl(&sb, NULL, 64, req);
254 
255 	sbuf_printf(&sb, "LDN8 (GPIO2, Watchdog): ");
256 	sbuf_printf(&sb, "CR%02X 0x%02x ", sc->ctl_reg, sc->reg_1);
257 	sbuf_printf(&sb, "CR%02X 0x%02x ", sc->time_reg, sc->reg_timeout);
258 	sbuf_printf(&sb, "CR%02X 0x%02x", sc->csr_reg, sc->reg_2);
259 
260 	error = sbuf_finish(&sb);
261 	sbuf_delete(&sb);
262 	return (error);
263 }
264 
265 /*
266  * Read the current values before returning them.  Given this might poke
267  * the registers the same time as the watchdog, this sysctl handler should
268  * be marked CTLFLAG_SKIP to not show up by default.
269  */
270 static int
271 sysctl_wb_debug_current(SYSCTL_HANDLER_ARGS)
272 {
273 	struct wb_softc *sc;
274 
275 	sc = arg1;
276 
277 	sc->reg_1 = superio_read(sc->dev, sc->ctl_reg);
278 	sc->reg_timeout = superio_read(sc->dev, sc->time_reg);
279 	sc->reg_2 = superio_read(sc->dev, sc->csr_reg);
280 
281 	return (sysctl_wb_debug(oidp, arg1, arg2, req));
282 }
283 
284 /*
285  * Sysctl handlers to force a watchdog timeout or to test the NMI functionality
286  * works as expetced.
287  * For testing we could set a test_nmi flag in the softc that, in case of NMI, a
288  * callback function from trap.c could check whether we fired and not report the
289  * timeout but clear the flag for the sysctl again.  This is interesting given a
290  * lot of boards have jumpers to change the action on watchdog timeout or
291  * disable the watchdog completely.
292  * XXX-BZ notyet: currently no general infrastructure exists to do this.
293  */
294 static int
295 sysctl_wb_force_test_nmi(SYSCTL_HANDLER_ARGS)
296 {
297 	struct wb_softc *sc;
298 	int error, test, val;
299 
300 	sc = arg1;
301 	test = arg2;
302 
303 #ifdef notyet
304 	val = sc->test_nmi;
305 #else
306 	val = 0;
307 #endif
308 	error = sysctl_handle_int(oidp, &val, 0, req);
309         if (error || !req->newptr)
310                 return (error);
311 
312 #ifdef notyet
313 	/* Manually clear the test for a value of 0 and do nothing else. */
314 	if (test && val == 0) {
315 		sc->test_nmi = 0;
316 		return (0);
317 	}
318 
319 	/*
320 	 * If we are testing the NMI functionality, set the flag before
321 	 * forcing the timeout.
322 	 */
323 	if (test)
324 		sc->test_nmi = 1;
325 #endif
326 
327 	/* Force watchdog to fire. */
328 	sc->reg_2 = superio_read(sc->dev, sc->csr_reg);
329 	sc->reg_2 |= WB_LDN8_CRF7_FORCE;
330 	superio_write(sc->dev, sc->csr_reg, sc->reg_2);
331 
332 	return (0);
333 }
334 
335 /*
336  * Print current watchdog state.
337  *
338  * Note: it is the responsibility of the caller to update the registers
339  * upfront.
340  */
341 static void
342 wb_print_state(struct wb_softc *sc, const char *msg)
343 {
344 
345 	device_printf(sc->dev, "%s%sWatchdog %sabled. %s"
346 	    "Scaling by %ds, timer at %d (%s=%ds%s). "
347 	    "CR%02X 0x%02x CR%02X 0x%02x\n",
348 	    (msg != NULL) ? msg : "", (msg != NULL) ? ": " : "",
349 	    (sc->reg_timeout > 0x00) ? "en" : "dis",
350 	    (sc->reg_2 & WB_LDN8_CRF7_TS) ? "Watchdog fired. " : "",
351 	    (sc->reg_1 & WB_LDN8_CRF5_SCALE) ? 60 : 1,
352 	    sc->reg_timeout,
353 	    (sc->reg_timeout > 0x00) ? "<" : "",
354 	    sc->reg_timeout * ((sc->reg_1 & WB_LDN8_CRF5_SCALE) ? 60 : 1),
355 	    (sc->reg_timeout > 0x00) ? " left" : "",
356 	    sc->ctl_reg, sc->reg_1, sc->csr_reg, sc->reg_2);
357 }
358 
359 /*
360  * (Re)load the watchdog counter depending on timeout.  A timeout of 0 will
361  * disable the watchdog.
362  */
363 static int
364 wb_set_watchdog(struct wb_softc *sc, unsigned int timeout)
365 {
366 
367 	if (timeout != 0) {
368 		/*
369 		 * In case an override is set, let it override.  It may lead
370 		 * to strange results as we do not check the input of the sysctl.
371 		 */
372 		if (sc->timeout_override > 0)
373 			timeout = sc->timeout_override;
374 
375 		/* Make sure we support the requested timeout. */
376 		if (timeout > 255 * 60)
377 			return (EINVAL);
378 	}
379 
380 	if (sc->debug_verbose)
381 		wb_print_state(sc, "Before watchdog counter (re)load");
382 
383 	if (timeout == 0) {
384 		/* Disable watchdog. */
385 		sc->reg_timeout = 0;
386 		superio_write(sc->dev, sc->time_reg, sc->reg_timeout);
387 
388 	} else {
389 		/* Read current scaling factor. */
390 		sc->reg_1 = superio_read(sc->dev, sc->ctl_reg);
391 
392 		if (timeout > 255) {
393 			/* Set scaling factor to 60s. */
394 			sc->reg_1 |= WB_LDN8_CRF5_SCALE;
395 			sc->reg_timeout = (timeout / 60);
396 			if (timeout % 60)
397 				sc->reg_timeout++;
398 		} else {
399 			/* Set scaling factor to 1s. */
400 			sc->reg_1 &= ~WB_LDN8_CRF5_SCALE;
401 			sc->reg_timeout = timeout;
402 		}
403 
404 		/* In case we fired before we need to clear to fire again. */
405 		sc->reg_2 = superio_read(sc->dev, sc->csr_reg);
406 		if (sc->reg_2 & WB_LDN8_CRF7_TS) {
407 			sc->reg_2 &= ~WB_LDN8_CRF7_TS;
408 			superio_write(sc->dev, sc->csr_reg, sc->reg_2);
409 		}
410 
411 		/* Write back scaling factor. */
412 		superio_write(sc->dev, sc->ctl_reg, sc->reg_1);
413 
414 		/* Set timer and arm/reset the watchdog. */
415 		superio_write(sc->dev, sc->time_reg, sc->reg_timeout);
416 	}
417 
418 	if (sc->debug_verbose)
419 		wb_print_state(sc, "After watchdog counter (re)load");
420 	return (0);
421 }
422 
423 /*
424  * watchdog(9) EVENTHANDLER function implementation to (re)load the counter
425  * with the given timeout or disable the watchdog.
426  */
427 static void
428 wb_watchdog_fn(void *private, u_int cmd, int *error)
429 {
430 	struct wb_softc *sc;
431 	unsigned int timeout;
432 	int e;
433 
434 	sc = private;
435 	KASSERT(sc != NULL, ("%s: watchdog handler function called without "
436 	    "softc.", __func__));
437 
438 	cmd &= WD_INTERVAL;
439 	if (cmd > 0 && cmd <= 63) {
440 		/* Reset (and arm) watchdog. */
441 		timeout = ((uint64_t)1 << cmd) / 1000000000;
442 		if (timeout == 0)
443 			timeout = 1;
444 		e = wb_set_watchdog(sc, timeout);
445 		if (e == 0) {
446 			if (error != NULL)
447 				*error = 0;
448 		} else {
449 			/* On error, try to make sure the WD is disabled. */
450 			wb_set_watchdog(sc, 0);
451 		}
452 
453 	} else {
454 		/* Disable watchdog. */
455 		e = wb_set_watchdog(sc, 0);
456 		if (e != 0 && cmd == 0 && error != NULL) {
457 			/* Failed to disable watchdog. */
458 			*error = EOPNOTSUPP;
459 		}
460 	}
461 }
462 
463 static int
464 wb_probe(device_t dev)
465 {
466 	char buf[128];
467 	struct wb_softc *sc;
468 	int j;
469 	uint8_t devid;
470 	uint8_t revid;
471 
472 	if (superio_vendor(dev) != SUPERIO_VENDOR_NUVOTON)
473 		return (ENXIO);
474 	if (superio_get_type(dev) != SUPERIO_DEV_WDT)
475 		return (ENXIO);
476 
477 	sc = device_get_softc(dev);
478 	devid = superio_devid(dev) >> 8;
479 	revid = superio_revid(dev);
480 	for (j = 0; j < nitems(wb_devs); j++) {
481 		if (wb_devs[j].device_id == devid) {
482 			sc->chip = wb_devs[j].chip;
483 			snprintf(buf, sizeof(buf),
484 			    "%s (0x%02x/0x%02x) Watchdog Timer",
485 			    wb_devs[j].descr, devid, revid);
486 			device_set_desc_copy(dev, buf);
487 			return (BUS_PROBE_SPECIFIC);
488 		}
489 	}
490 	if (bootverbose) {
491 		device_printf(dev,
492 		    "unrecognized chip: devid 0x%02x, revid 0x%02x\n",
493 		    devid, revid);
494 	}
495 	return (ENXIO);
496 }
497 
498 static int
499 wb_attach(device_t dev)
500 {
501 	struct wb_softc *sc;
502 	struct sysctl_ctx_list *sctx;
503 	struct sysctl_oid *soid;
504 	unsigned long timeout;
505 	uint8_t t;
506 
507 	sc = device_get_softc(dev);
508 	sc->dev = dev;
509 
510 	/* Make sure WDT is enabled. */
511 	superio_dev_enable(dev, WB_LDN8_CR30_ACTIVE);
512 
513 	switch (sc->chip) {
514 	case w83697hf:
515 	case w83697ug:
516 		sc->ctl_reg = 0xf3;
517 		sc->time_reg = 0xf4;
518 		sc->csr_reg = 0xf7;
519 		break;
520 	case nct6102:
521 		sc->ctl_reg = 0xf0;
522 		sc->time_reg = 0xf1;
523 		sc->csr_reg = 0xf2;
524 		break;
525 	default:
526 		sc->ctl_reg = 0xf5;
527 		sc->time_reg = 0xf6;
528 		sc->csr_reg = 0xf7;
529 		break;
530 	}
531 
532 	switch (sc->chip) {
533 	case w83627hf:
534 	case w83627s:
535 		t = superio_read(dev, 0x2B) & ~0x10;
536 		superio_write(dev, 0x2B, t); /* set GPIO24 to WDT0 */
537 		break;
538 	case w83697hf:
539 		/* Set pin 119 to WDTO# mode (= CR29, WDT0) */
540 		t = superio_read(dev, 0x29) & ~0x60;
541 		t |= 0x20;
542 		superio_write(dev, 0x29, t);
543 		break;
544 	case w83697ug:
545 		/* Set pin 118 to WDTO# mode */
546 		t = superio_read(dev, 0x2b) & ~0x04;
547 		superio_write(dev, 0x2b, t);
548 		break;
549 	case w83627thf:
550 		t = (superio_read(dev, 0x2B) & ~0x08) | 0x04;
551 		superio_write(dev, 0x2B, t); /* set GPIO3 to WDT0 */
552 		break;
553 	case w83627dhg:
554 	case w83627dhg_p:
555 		t = superio_read(dev, 0x2D) & ~0x01; /* PIN77 -> WDT0# */
556 		superio_write(dev, 0x2D, t); /* set GPIO5 to WDT0 */
557 		t = superio_read(dev, sc->ctl_reg);
558 		t |= 0x02;	/* enable the WDTO# output low pulse
559 				 * to the KBRST# pin */
560 		superio_write(dev, sc->ctl_reg, t);
561 		break;
562 	case w83637hf:
563 		break;
564 	case w83687thf:
565 		t = superio_read(dev, 0x2C) & ~0x80; /* PIN47 -> WDT0# */
566 		superio_write(dev, 0x2C, t);
567 		break;
568 	case w83627ehf:
569 	case w83627uhg:
570 	case w83667hg:
571 	case w83667hg_b:
572 	case nct6775:
573 	case nct6776:
574 	case nct6779:
575 	case nct6791:
576 	case nct6792:
577 	case nct6793:
578 	case nct6795:
579 	case nct6102:
580 		/*
581 		 * These chips have a fixed WDTO# output pin (W83627UHG),
582 		 * or support more than one WDTO# output pin.
583 		 * Don't touch its configuration, and hope the BIOS
584 		 * does the right thing.
585 		 */
586 		t = superio_read(dev, sc->ctl_reg);
587 		t |= 0x02;	/* enable the WDTO# output low pulse
588 				 * to the KBRST# pin */
589 		superio_write(dev, sc->ctl_reg, t);
590 		break;
591 	default:
592 		break;
593 	}
594 
595 	/* Read the current watchdog configuration. */
596 	sc->reg_1 = superio_read(dev, sc->ctl_reg);
597 	sc->reg_timeout = superio_read(dev, sc->time_reg);
598 	sc->reg_2 = superio_read(dev, sc->csr_reg);
599 
600 	/* Print current state if bootverbose or watchdog already enabled. */
601 	if (bootverbose || (sc->reg_timeout > 0x00))
602 		wb_print_state(sc, "Before watchdog attach");
603 
604 	sc->reg_1 &= ~WB_LDN8_CRF5_KEYB_P20;
605 	sc->reg_1 |= WB_LDN8_CRF5_KBRST;
606 	superio_write(dev, sc->ctl_reg, sc->reg_1);
607 
608 	/*
609 	 * Clear a previous watchdog timeout event (if still set).
610 	 * Disable timer reset on mouse interrupts.  Leave reset on keyboard,
611 	 * since one of my boards is getting stuck in reboot without it.
612 	 */
613 	sc->reg_2 &= ~(WB_LDN8_CRF7_MOUSE|WB_LDN8_CRF7_TS);
614 	superio_write(dev, sc->csr_reg, sc->reg_2);
615 
616 	/* Read global timeout override tunable, Add per device sysctls. */
617 	if (TUNABLE_ULONG_FETCH("hw.wbwd.timeout_override", &timeout)) {
618 		if (timeout > 0)
619 			sc->timeout_override = timeout;
620 	}
621 	sctx = device_get_sysctl_ctx(dev);
622 	soid = device_get_sysctl_tree(dev);
623         SYSCTL_ADD_UINT(sctx, SYSCTL_CHILDREN(soid), OID_AUTO,
624 	    "timeout_override", CTLFLAG_RW, &sc->timeout_override, 0,
625             "Timeout in seconds overriding default watchdog timeout");
626         SYSCTL_ADD_INT(sctx, SYSCTL_CHILDREN(soid), OID_AUTO,
627 	    "debug_verbose", CTLFLAG_RW, &sc->debug_verbose, 0,
628             "Enables extra debugging information");
629         SYSCTL_ADD_PROC(sctx, SYSCTL_CHILDREN(soid), OID_AUTO, "debug",
630 	    CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_NEEDGIANT, sc, 0,
631 	    sysctl_wb_debug, "A",
632             "Selected register information from last change by driver");
633         SYSCTL_ADD_PROC(sctx, SYSCTL_CHILDREN(soid), OID_AUTO, "debug_current",
634 	    CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP | CTLFLAG_NEEDGIANT,
635 	    sc, 0, sysctl_wb_debug_current, "A",
636 	     "Selected register information (may interfere)");
637 	SYSCTL_ADD_PROC(sctx, SYSCTL_CHILDREN(soid), OID_AUTO, "force_timeout",
638 	    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SKIP | CTLFLAG_NEEDGIANT, sc, 0,
639 	    sysctl_wb_force_test_nmi, "I", "Enable to force watchdog to fire.");
640 
641 	/* Register watchdog. */
642 	sc->ev_tag = EVENTHANDLER_REGISTER(watchdog_list, wb_watchdog_fn, sc,
643 	    0);
644 
645 	if (bootverbose)
646 		wb_print_state(sc, "After watchdog attach");
647 
648 	return (0);
649 }
650 
651 static int
652 wb_detach(device_t dev)
653 {
654 	struct wb_softc *sc;
655 
656 	sc = device_get_softc(dev);
657 
658 	/* Unregister and stop the watchdog if running. */
659 	if (sc->ev_tag)
660 		EVENTHANDLER_DEREGISTER(watchdog_list, sc->ev_tag);
661 	wb_set_watchdog(sc, 0);
662 
663 	/* Bus subroutines take care of sysctls already. */
664 
665 	return (0);
666 }
667 
668 static device_method_t wb_methods[] = {
669 	/* Device interface */
670 	DEVMETHOD(device_probe,		wb_probe),
671 	DEVMETHOD(device_attach,	wb_attach),
672 	DEVMETHOD(device_detach,	wb_detach),
673 
674 	DEVMETHOD_END
675 };
676 
677 static driver_t wb_driver = {
678 	"wbwd",
679 	wb_methods,
680 	sizeof(struct wb_softc)
681 };
682 
683 static devclass_t wb_devclass;
684 
685 DRIVER_MODULE(wb, superio, wb_driver, wb_devclass, NULL, NULL);
686 MODULE_DEPEND(wb, superio, 1, 1, 1);
687 MODULE_VERSION(wb, 1);
688