1 /*
2  *	w83627hf/thf WDT driver
3  *
4  *	(c) Copyright 2013 Guenter Roeck
5  *		converted to watchdog infrastructure
6  *
7  *	(c) Copyright 2007 Vlad Drukker <vlad@storewiz.com>
8  *		added support for W83627THF.
9  *
10  *	(c) Copyright 2003,2007 Pádraig Brady <P@draigBrady.com>
11  *
12  *	Based on advantechwdt.c which is based on wdt.c.
13  *	Original copyright messages:
14  *
15  *	(c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
16  *
17  *	(c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
18  *						All Rights Reserved.
19  *
20  *	This program is free software; you can redistribute it and/or
21  *	modify it under the terms of the GNU General Public License
22  *	as published by the Free Software Foundation; either version
23  *	2 of the License, or (at your option) any later version.
24  *
25  *	Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
26  *	warranty for any of this software. This material is provided
27  *	"AS-IS" and at no charge.
28  *
29  *	(c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>
30  */
31 
32 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
33 
34 #include <linux/module.h>
35 #include <linux/moduleparam.h>
36 #include <linux/types.h>
37 #include <linux/watchdog.h>
38 #include <linux/ioport.h>
39 #include <linux/notifier.h>
40 #include <linux/reboot.h>
41 #include <linux/init.h>
42 #include <linux/io.h>
43 
44 #define WATCHDOG_NAME "w83627hf/thf/hg/dhg WDT"
45 #define WATCHDOG_TIMEOUT 60		/* 60 sec default timeout */
46 
47 static int wdt_io;
48 static int cr_wdt_timeout;	/* WDT timeout register */
49 static int cr_wdt_control;	/* WDT control register */
50 
51 enum chips { w83627hf, w83627s, w83697hf, w83697ug, w83637hf, w83627thf,
52 	     w83687thf, w83627ehf, w83627dhg, w83627uhg, w83667hg, w83627dhg_p,
53 	     w83667hg_b, nct6775, nct6776, nct6779, nct6791, nct6792 };
54 
55 static int timeout;			/* in seconds */
56 module_param(timeout, int, 0);
57 MODULE_PARM_DESC(timeout,
58 		"Watchdog timeout in seconds. 1 <= timeout <= 255, default="
59 				__MODULE_STRING(WATCHDOG_TIMEOUT) ".");
60 
61 static bool nowayout = WATCHDOG_NOWAYOUT;
62 module_param(nowayout, bool, 0);
63 MODULE_PARM_DESC(nowayout,
64 		"Watchdog cannot be stopped once started (default="
65 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
66 
67 static int early_disable;
68 module_param(early_disable, int, 0);
69 MODULE_PARM_DESC(early_disable, "Disable watchdog at boot time (default=0)");
70 
71 /*
72  *	Kernel methods.
73  */
74 
75 #define WDT_EFER (wdt_io+0)   /* Extended Function Enable Registers */
76 #define WDT_EFIR (wdt_io+0)   /* Extended Function Index Register
77 							(same as EFER) */
78 #define WDT_EFDR (WDT_EFIR+1) /* Extended Function Data Register */
79 
80 #define W83627HF_LD_WDT		0x08
81 
82 #define W83627HF_ID		0x52
83 #define W83627S_ID		0x59
84 #define W83697HF_ID		0x60
85 #define W83697UG_ID		0x68
86 #define W83637HF_ID		0x70
87 #define W83627THF_ID		0x82
88 #define W83687THF_ID		0x85
89 #define W83627EHF_ID		0x88
90 #define W83627DHG_ID		0xa0
91 #define W83627UHG_ID		0xa2
92 #define W83667HG_ID		0xa5
93 #define W83627DHG_P_ID		0xb0
94 #define W83667HG_B_ID		0xb3
95 #define NCT6775_ID		0xb4
96 #define NCT6776_ID		0xc3
97 #define NCT6779_ID		0xc5
98 #define NCT6791_ID		0xc8
99 #define NCT6792_ID		0xc9
100 
101 #define W83627HF_WDT_TIMEOUT	0xf6
102 #define W83697HF_WDT_TIMEOUT	0xf4
103 
104 #define W83627HF_WDT_CONTROL	0xf5
105 #define W83697HF_WDT_CONTROL	0xf3
106 
107 static void superio_outb(int reg, int val)
108 {
109 	outb(reg, WDT_EFER);
110 	outb(val, WDT_EFDR);
111 }
112 
113 static inline int superio_inb(int reg)
114 {
115 	outb(reg, WDT_EFER);
116 	return inb(WDT_EFDR);
117 }
118 
119 static int superio_enter(void)
120 {
121 	if (!request_muxed_region(wdt_io, 2, WATCHDOG_NAME))
122 		return -EBUSY;
123 
124 	outb_p(0x87, WDT_EFER); /* Enter extended function mode */
125 	outb_p(0x87, WDT_EFER); /* Again according to manual */
126 
127 	return 0;
128 }
129 
130 static void superio_select(int ld)
131 {
132 	superio_outb(0x07, ld);
133 }
134 
135 static void superio_exit(void)
136 {
137 	outb_p(0xAA, WDT_EFER); /* Leave extended function mode */
138 	release_region(wdt_io, 2);
139 }
140 
141 static int w83627hf_init(struct watchdog_device *wdog, enum chips chip)
142 {
143 	int ret;
144 	unsigned char t;
145 
146 	ret = superio_enter();
147 	if (ret)
148 		return ret;
149 
150 	superio_select(W83627HF_LD_WDT);
151 
152 	/* set CR30 bit 0 to activate GPIO2 */
153 	t = superio_inb(0x30);
154 	if (!(t & 0x01))
155 		superio_outb(0x30, t | 0x01);
156 
157 	switch (chip) {
158 	case w83627hf:
159 	case w83627s:
160 		t = superio_inb(0x2B) & ~0x10;
161 		superio_outb(0x2B, t); /* set GPIO24 to WDT0 */
162 		break;
163 	case w83697hf:
164 		/* Set pin 119 to WDTO# mode (= CR29, WDT0) */
165 		t = superio_inb(0x29) & ~0x60;
166 		t |= 0x20;
167 		superio_outb(0x29, t);
168 		break;
169 	case w83697ug:
170 		/* Set pin 118 to WDTO# mode */
171 		t = superio_inb(0x2b) & ~0x04;
172 		superio_outb(0x2b, t);
173 		break;
174 	case w83627thf:
175 		t = (superio_inb(0x2B) & ~0x08) | 0x04;
176 		superio_outb(0x2B, t); /* set GPIO3 to WDT0 */
177 		break;
178 	case w83627dhg:
179 	case w83627dhg_p:
180 		t = superio_inb(0x2D) & ~0x01; /* PIN77 -> WDT0# */
181 		superio_outb(0x2D, t); /* set GPIO5 to WDT0 */
182 		t = superio_inb(cr_wdt_control);
183 		t |= 0x02;	/* enable the WDTO# output low pulse
184 				 * to the KBRST# pin */
185 		superio_outb(cr_wdt_control, t);
186 		break;
187 	case w83637hf:
188 		break;
189 	case w83687thf:
190 		t = superio_inb(0x2C) & ~0x80; /* PIN47 -> WDT0# */
191 		superio_outb(0x2C, t);
192 		break;
193 	case w83627ehf:
194 	case w83627uhg:
195 	case w83667hg:
196 	case w83667hg_b:
197 	case nct6775:
198 	case nct6776:
199 	case nct6779:
200 	case nct6791:
201 	case nct6792:
202 		/*
203 		 * These chips have a fixed WDTO# output pin (W83627UHG),
204 		 * or support more than one WDTO# output pin.
205 		 * Don't touch its configuration, and hope the BIOS
206 		 * does the right thing.
207 		 */
208 		t = superio_inb(cr_wdt_control);
209 		t |= 0x02;	/* enable the WDTO# output low pulse
210 				 * to the KBRST# pin */
211 		superio_outb(cr_wdt_control, t);
212 		break;
213 	default:
214 		break;
215 	}
216 
217 	t = superio_inb(cr_wdt_timeout);
218 	if (t != 0) {
219 		if (early_disable) {
220 			pr_warn("Stopping previously enabled watchdog until userland kicks in\n");
221 			superio_outb(cr_wdt_timeout, 0);
222 		} else {
223 			pr_info("Watchdog already running. Resetting timeout to %d sec\n",
224 				wdog->timeout);
225 			superio_outb(cr_wdt_timeout, wdog->timeout);
226 		}
227 	}
228 
229 	/* set second mode & disable keyboard turning off watchdog */
230 	t = superio_inb(cr_wdt_control) & ~0x0C;
231 	superio_outb(cr_wdt_control, t);
232 
233 	/* reset trigger, disable keyboard & mouse turning off watchdog */
234 	t = superio_inb(0xF7) & ~0xD0;
235 	superio_outb(0xF7, t);
236 
237 	superio_exit();
238 
239 	return 0;
240 }
241 
242 static int wdt_set_time(unsigned int timeout)
243 {
244 	int ret;
245 
246 	ret = superio_enter();
247 	if (ret)
248 		return ret;
249 
250 	superio_select(W83627HF_LD_WDT);
251 	superio_outb(cr_wdt_timeout, timeout);
252 	superio_exit();
253 
254 	return 0;
255 }
256 
257 static int wdt_start(struct watchdog_device *wdog)
258 {
259 	return wdt_set_time(wdog->timeout);
260 }
261 
262 static int wdt_stop(struct watchdog_device *wdog)
263 {
264 	return wdt_set_time(0);
265 }
266 
267 static int wdt_set_timeout(struct watchdog_device *wdog, unsigned int timeout)
268 {
269 	wdog->timeout = timeout;
270 
271 	return 0;
272 }
273 
274 static unsigned int wdt_get_time(struct watchdog_device *wdog)
275 {
276 	unsigned int timeleft;
277 	int ret;
278 
279 	ret = superio_enter();
280 	if (ret)
281 		return 0;
282 
283 	superio_select(W83627HF_LD_WDT);
284 	timeleft = superio_inb(cr_wdt_timeout);
285 	superio_exit();
286 
287 	return timeleft;
288 }
289 
290 /*
291  *	Notifier for system down
292  */
293 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
294 	void *unused)
295 {
296 	if (code == SYS_DOWN || code == SYS_HALT)
297 		wdt_set_time(0);	/* Turn the WDT off */
298 
299 	return NOTIFY_DONE;
300 }
301 
302 /*
303  *	Kernel Interfaces
304  */
305 
306 static struct watchdog_info wdt_info = {
307 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
308 	.identity = "W83627HF Watchdog",
309 };
310 
311 static struct watchdog_ops wdt_ops = {
312 	.owner = THIS_MODULE,
313 	.start = wdt_start,
314 	.stop = wdt_stop,
315 	.set_timeout = wdt_set_timeout,
316 	.get_timeleft = wdt_get_time,
317 };
318 
319 static struct watchdog_device wdt_dev = {
320 	.info = &wdt_info,
321 	.ops = &wdt_ops,
322 	.timeout = WATCHDOG_TIMEOUT,
323 	.min_timeout = 1,
324 	.max_timeout = 255,
325 };
326 
327 /*
328  *	The WDT needs to learn about soft shutdowns in order to
329  *	turn the timebomb registers off.
330  */
331 
332 static struct notifier_block wdt_notifier = {
333 	.notifier_call = wdt_notify_sys,
334 };
335 
336 static int wdt_find(int addr)
337 {
338 	u8 val;
339 	int ret;
340 
341 	cr_wdt_timeout = W83627HF_WDT_TIMEOUT;
342 	cr_wdt_control = W83627HF_WDT_CONTROL;
343 
344 	ret = superio_enter();
345 	if (ret)
346 		return ret;
347 	superio_select(W83627HF_LD_WDT);
348 	val = superio_inb(0x20);
349 	switch (val) {
350 	case W83627HF_ID:
351 		ret = w83627hf;
352 		break;
353 	case W83627S_ID:
354 		ret = w83627s;
355 		break;
356 	case W83697HF_ID:
357 		ret = w83697hf;
358 		cr_wdt_timeout = W83697HF_WDT_TIMEOUT;
359 		cr_wdt_control = W83697HF_WDT_CONTROL;
360 		break;
361 	case W83697UG_ID:
362 		ret = w83697ug;
363 		cr_wdt_timeout = W83697HF_WDT_TIMEOUT;
364 		cr_wdt_control = W83697HF_WDT_CONTROL;
365 		break;
366 	case W83637HF_ID:
367 		ret = w83637hf;
368 		break;
369 	case W83627THF_ID:
370 		ret = w83627thf;
371 		break;
372 	case W83687THF_ID:
373 		ret = w83687thf;
374 		break;
375 	case W83627EHF_ID:
376 		ret = w83627ehf;
377 		break;
378 	case W83627DHG_ID:
379 		ret = w83627dhg;
380 		break;
381 	case W83627DHG_P_ID:
382 		ret = w83627dhg_p;
383 		break;
384 	case W83627UHG_ID:
385 		ret = w83627uhg;
386 		break;
387 	case W83667HG_ID:
388 		ret = w83667hg;
389 		break;
390 	case W83667HG_B_ID:
391 		ret = w83667hg_b;
392 		break;
393 	case NCT6775_ID:
394 		ret = nct6775;
395 		break;
396 	case NCT6776_ID:
397 		ret = nct6776;
398 		break;
399 	case NCT6779_ID:
400 		ret = nct6779;
401 		break;
402 	case NCT6791_ID:
403 		ret = nct6791;
404 		break;
405 	case NCT6792_ID:
406 		ret = nct6792;
407 		break;
408 	case 0xff:
409 		ret = -ENODEV;
410 		break;
411 	default:
412 		ret = -ENODEV;
413 		pr_err("Unsupported chip ID: 0x%02x\n", val);
414 		break;
415 	}
416 	superio_exit();
417 	return ret;
418 }
419 
420 static int __init wdt_init(void)
421 {
422 	int ret;
423 	int chip;
424 	const char * const chip_name[] = {
425 		"W83627HF",
426 		"W83627S",
427 		"W83697HF",
428 		"W83697UG",
429 		"W83637HF",
430 		"W83627THF",
431 		"W83687THF",
432 		"W83627EHF",
433 		"W83627DHG",
434 		"W83627UHG",
435 		"W83667HG",
436 		"W83667DHG-P",
437 		"W83667HG-B",
438 		"NCT6775",
439 		"NCT6776",
440 		"NCT6779",
441 		"NCT6791",
442 		"NCT6792",
443 	};
444 
445 	wdt_io = 0x2e;
446 	chip = wdt_find(0x2e);
447 	if (chip < 0) {
448 		wdt_io = 0x4e;
449 		chip = wdt_find(0x4e);
450 		if (chip < 0)
451 			return chip;
452 	}
453 
454 	pr_info("WDT driver for %s Super I/O chip initialising\n",
455 		chip_name[chip]);
456 
457 	watchdog_init_timeout(&wdt_dev, timeout, NULL);
458 	watchdog_set_nowayout(&wdt_dev, nowayout);
459 
460 	ret = w83627hf_init(&wdt_dev, chip);
461 	if (ret) {
462 		pr_err("failed to initialize watchdog (err=%d)\n", ret);
463 		return ret;
464 	}
465 
466 	ret = register_reboot_notifier(&wdt_notifier);
467 	if (ret != 0) {
468 		pr_err("cannot register reboot notifier (err=%d)\n", ret);
469 		return ret;
470 	}
471 
472 	ret = watchdog_register_device(&wdt_dev);
473 	if (ret)
474 		goto unreg_reboot;
475 
476 	pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
477 		wdt_dev.timeout, nowayout);
478 
479 	return ret;
480 
481 unreg_reboot:
482 	unregister_reboot_notifier(&wdt_notifier);
483 	return ret;
484 }
485 
486 static void __exit wdt_exit(void)
487 {
488 	watchdog_unregister_device(&wdt_dev);
489 	unregister_reboot_notifier(&wdt_notifier);
490 }
491 
492 module_init(wdt_init);
493 module_exit(wdt_exit);
494 
495 MODULE_LICENSE("GPL");
496 MODULE_AUTHOR("Pádraig  Brady <P@draigBrady.com>");
497 MODULE_DESCRIPTION("w83627hf/thf WDT driver");
498