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 };
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 
99 #define W83627HF_WDT_TIMEOUT	0xf6
100 #define W83697HF_WDT_TIMEOUT	0xf4
101 
102 #define W83627HF_WDT_CONTROL	0xf5
103 #define W83697HF_WDT_CONTROL	0xf3
104 
105 static void superio_outb(int reg, int val)
106 {
107 	outb(reg, WDT_EFER);
108 	outb(val, WDT_EFDR);
109 }
110 
111 static inline int superio_inb(int reg)
112 {
113 	outb(reg, WDT_EFER);
114 	return inb(WDT_EFDR);
115 }
116 
117 static int superio_enter(void)
118 {
119 	if (!request_muxed_region(wdt_io, 2, WATCHDOG_NAME))
120 		return -EBUSY;
121 
122 	outb_p(0x87, WDT_EFER); /* Enter extended function mode */
123 	outb_p(0x87, WDT_EFER); /* Again according to manual */
124 
125 	return 0;
126 }
127 
128 static void superio_select(int ld)
129 {
130 	superio_outb(0x07, ld);
131 }
132 
133 static void superio_exit(void)
134 {
135 	outb_p(0xAA, WDT_EFER); /* Leave extended function mode */
136 	release_region(wdt_io, 2);
137 }
138 
139 static int w83627hf_init(struct watchdog_device *wdog, enum chips chip)
140 {
141 	int ret;
142 	unsigned char t;
143 
144 	ret = superio_enter();
145 	if (ret)
146 		return ret;
147 
148 	superio_select(W83627HF_LD_WDT);
149 
150 	/* set CR30 bit 0 to activate GPIO2 */
151 	t = superio_inb(0x30);
152 	if (!(t & 0x01))
153 		superio_outb(0x30, t | 0x01);
154 
155 	switch (chip) {
156 	case w83627hf:
157 	case w83627s:
158 		t = superio_inb(0x2B) & ~0x10;
159 		superio_outb(0x2B, t); /* set GPIO24 to WDT0 */
160 		break;
161 	case w83697hf:
162 		/* Set pin 119 to WDTO# mode (= CR29, WDT0) */
163 		t = superio_inb(0x29) & ~0x60;
164 		t |= 0x20;
165 		superio_outb(0x29, t);
166 		break;
167 	case w83697ug:
168 		/* Set pin 118 to WDTO# mode */
169 		t = superio_inb(0x2b) & ~0x04;
170 		superio_outb(0x2b, t);
171 		break;
172 	case w83627thf:
173 		t = (superio_inb(0x2B) & ~0x08) | 0x04;
174 		superio_outb(0x2B, t); /* set GPIO3 to WDT0 */
175 		break;
176 	case w83627dhg:
177 	case w83627dhg_p:
178 		t = superio_inb(0x2D) & ~0x01; /* PIN77 -> WDT0# */
179 		superio_outb(0x2D, t); /* set GPIO5 to WDT0 */
180 		t = superio_inb(cr_wdt_control);
181 		t |= 0x02;	/* enable the WDTO# output low pulse
182 				 * to the KBRST# pin */
183 		superio_outb(cr_wdt_control, t);
184 		break;
185 	case w83637hf:
186 		break;
187 	case w83687thf:
188 		t = superio_inb(0x2C) & ~0x80; /* PIN47 -> WDT0# */
189 		superio_outb(0x2C, t);
190 		break;
191 	case w83627ehf:
192 	case w83627uhg:
193 	case w83667hg:
194 	case w83667hg_b:
195 	case nct6775:
196 	case nct6776:
197 	case nct6779:
198 		/*
199 		 * These chips have a fixed WDTO# output pin (W83627UHG),
200 		 * or support more than one WDTO# output pin.
201 		 * Don't touch its configuration, and hope the BIOS
202 		 * does the right thing.
203 		 */
204 		t = superio_inb(cr_wdt_control);
205 		t |= 0x02;	/* enable the WDTO# output low pulse
206 				 * to the KBRST# pin */
207 		superio_outb(cr_wdt_control, t);
208 		break;
209 	default:
210 		break;
211 	}
212 
213 	t = superio_inb(cr_wdt_timeout);
214 	if (t != 0) {
215 		if (early_disable) {
216 			pr_warn("Stopping previously enabled watchdog until userland kicks in\n");
217 			superio_outb(cr_wdt_timeout, 0);
218 		} else {
219 			pr_info("Watchdog already running. Resetting timeout to %d sec\n",
220 				wdog->timeout);
221 			superio_outb(cr_wdt_timeout, wdog->timeout);
222 		}
223 	}
224 
225 	/* set second mode & disable keyboard turning off watchdog */
226 	t = superio_inb(cr_wdt_control) & ~0x0C;
227 	superio_outb(cr_wdt_control, t);
228 
229 	/* reset trigger, disable keyboard & mouse turning off watchdog */
230 	t = superio_inb(0xF7) & ~0xD0;
231 	superio_outb(0xF7, t);
232 
233 	superio_exit();
234 
235 	return 0;
236 }
237 
238 static int wdt_set_time(unsigned int timeout)
239 {
240 	int ret;
241 
242 	ret = superio_enter();
243 	if (ret)
244 		return ret;
245 
246 	superio_select(W83627HF_LD_WDT);
247 	superio_outb(cr_wdt_timeout, timeout);
248 	superio_exit();
249 
250 	return 0;
251 }
252 
253 static int wdt_start(struct watchdog_device *wdog)
254 {
255 	return wdt_set_time(wdog->timeout);
256 }
257 
258 static int wdt_stop(struct watchdog_device *wdog)
259 {
260 	return wdt_set_time(0);
261 }
262 
263 static int wdt_set_timeout(struct watchdog_device *wdog, unsigned int timeout)
264 {
265 	wdog->timeout = timeout;
266 
267 	return 0;
268 }
269 
270 static unsigned int wdt_get_time(struct watchdog_device *wdog)
271 {
272 	unsigned int timeleft;
273 	int ret;
274 
275 	ret = superio_enter();
276 	if (ret)
277 		return 0;
278 
279 	superio_select(W83627HF_LD_WDT);
280 	timeleft = superio_inb(cr_wdt_timeout);
281 	superio_exit();
282 
283 	return timeleft;
284 }
285 
286 /*
287  *	Notifier for system down
288  */
289 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
290 	void *unused)
291 {
292 	if (code == SYS_DOWN || code == SYS_HALT)
293 		wdt_set_time(0);	/* Turn the WDT off */
294 
295 	return NOTIFY_DONE;
296 }
297 
298 /*
299  *	Kernel Interfaces
300  */
301 
302 static struct watchdog_info wdt_info = {
303 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
304 	.identity = "W83627HF Watchdog",
305 };
306 
307 static struct watchdog_ops wdt_ops = {
308 	.owner = THIS_MODULE,
309 	.start = wdt_start,
310 	.stop = wdt_stop,
311 	.set_timeout = wdt_set_timeout,
312 	.get_timeleft = wdt_get_time,
313 };
314 
315 static struct watchdog_device wdt_dev = {
316 	.info = &wdt_info,
317 	.ops = &wdt_ops,
318 	.timeout = WATCHDOG_TIMEOUT,
319 	.min_timeout = 1,
320 	.max_timeout = 255,
321 };
322 
323 /*
324  *	The WDT needs to learn about soft shutdowns in order to
325  *	turn the timebomb registers off.
326  */
327 
328 static struct notifier_block wdt_notifier = {
329 	.notifier_call = wdt_notify_sys,
330 };
331 
332 static int wdt_find(int addr)
333 {
334 	u8 val;
335 	int ret;
336 
337 	cr_wdt_timeout = W83627HF_WDT_TIMEOUT;
338 	cr_wdt_control = W83627HF_WDT_CONTROL;
339 
340 	ret = superio_enter();
341 	if (ret)
342 		return ret;
343 	superio_select(W83627HF_LD_WDT);
344 	val = superio_inb(0x20);
345 	switch (val) {
346 	case W83627HF_ID:
347 		ret = w83627hf;
348 		break;
349 	case W83627S_ID:
350 		ret = w83627s;
351 		break;
352 	case W83697HF_ID:
353 		ret = w83697hf;
354 		cr_wdt_timeout = W83697HF_WDT_TIMEOUT;
355 		cr_wdt_control = W83697HF_WDT_CONTROL;
356 		break;
357 	case W83697UG_ID:
358 		ret = w83697ug;
359 		cr_wdt_timeout = W83697HF_WDT_TIMEOUT;
360 		cr_wdt_control = W83697HF_WDT_CONTROL;
361 		break;
362 	case W83637HF_ID:
363 		ret = w83637hf;
364 		break;
365 	case W83627THF_ID:
366 		ret = w83627thf;
367 		break;
368 	case W83687THF_ID:
369 		ret = w83687thf;
370 		break;
371 	case W83627EHF_ID:
372 		ret = w83627ehf;
373 		break;
374 	case W83627DHG_ID:
375 		ret = w83627dhg;
376 		break;
377 	case W83627DHG_P_ID:
378 		ret = w83627dhg_p;
379 		break;
380 	case W83627UHG_ID:
381 		ret = w83627uhg;
382 		break;
383 	case W83667HG_ID:
384 		ret = w83667hg;
385 		break;
386 	case W83667HG_B_ID:
387 		ret = w83667hg_b;
388 		break;
389 	case NCT6775_ID:
390 		ret = nct6775;
391 		break;
392 	case NCT6776_ID:
393 		ret = nct6776;
394 		break;
395 	case NCT6779_ID:
396 		ret = nct6779;
397 		break;
398 	case 0xff:
399 		ret = -ENODEV;
400 		break;
401 	default:
402 		ret = -ENODEV;
403 		pr_err("Unsupported chip ID: 0x%02x\n", val);
404 		break;
405 	}
406 	superio_exit();
407 	return ret;
408 }
409 
410 static int __init wdt_init(void)
411 {
412 	int ret;
413 	int chip;
414 	const char * const chip_name[] = {
415 		"W83627HF",
416 		"W83627S",
417 		"W83697HF",
418 		"W83697UG",
419 		"W83637HF",
420 		"W83627THF",
421 		"W83687THF",
422 		"W83627EHF",
423 		"W83627DHG",
424 		"W83627UHG",
425 		"W83667HG",
426 		"W83667DHG-P",
427 		"W83667HG-B",
428 		"NCT6775",
429 		"NCT6776",
430 		"NCT6779",
431 	};
432 
433 	wdt_io = 0x2e;
434 	chip = wdt_find(0x2e);
435 	if (chip < 0) {
436 		wdt_io = 0x4e;
437 		chip = wdt_find(0x4e);
438 		if (chip < 0)
439 			return chip;
440 	}
441 
442 	pr_info("WDT driver for %s Super I/O chip initialising\n",
443 		chip_name[chip]);
444 
445 	watchdog_init_timeout(&wdt_dev, timeout, NULL);
446 	watchdog_set_nowayout(&wdt_dev, nowayout);
447 
448 	ret = w83627hf_init(&wdt_dev, chip);
449 	if (ret) {
450 		pr_err("failed to initialize watchdog (err=%d)\n", ret);
451 		return ret;
452 	}
453 
454 	ret = register_reboot_notifier(&wdt_notifier);
455 	if (ret != 0) {
456 		pr_err("cannot register reboot notifier (err=%d)\n", ret);
457 		return ret;
458 	}
459 
460 	ret = watchdog_register_device(&wdt_dev);
461 	if (ret)
462 		goto unreg_reboot;
463 
464 	pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
465 		wdt_dev.timeout, nowayout);
466 
467 	return ret;
468 
469 unreg_reboot:
470 	unregister_reboot_notifier(&wdt_notifier);
471 	return ret;
472 }
473 
474 static void __exit wdt_exit(void)
475 {
476 	watchdog_unregister_device(&wdt_dev);
477 	unregister_reboot_notifier(&wdt_notifier);
478 }
479 
480 module_init(wdt_init);
481 module_exit(wdt_exit);
482 
483 MODULE_LICENSE("GPL");
484 MODULE_AUTHOR("Pádraig  Brady <P@draigBrady.com>");
485 MODULE_DESCRIPTION("w83627hf/thf WDT driver");
486