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 /* You must set this - there is no sane way to probe for this board. */
48 static int wdt_io = 0x2E;
49 module_param(wdt_io, int, 0);
50 MODULE_PARM_DESC(wdt_io, "w83627hf/thf WDT io port (default 0x2E)");
51 
52 static int timeout;			/* in seconds */
53 module_param(timeout, int, 0);
54 MODULE_PARM_DESC(timeout,
55 		"Watchdog timeout in seconds. 1 <= timeout <= 255, default="
56 				__MODULE_STRING(WATCHDOG_TIMEOUT) ".");
57 
58 static bool nowayout = WATCHDOG_NOWAYOUT;
59 module_param(nowayout, bool, 0);
60 MODULE_PARM_DESC(nowayout,
61 		"Watchdog cannot be stopped once started (default="
62 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
63 
64 /*
65  *	Kernel methods.
66  */
67 
68 #define WDT_EFER (wdt_io+0)   /* Extended Function Enable Registers */
69 #define WDT_EFIR (wdt_io+0)   /* Extended Function Index Register
70 							(same as EFER) */
71 #define WDT_EFDR (WDT_EFIR+1) /* Extended Function Data Register */
72 
73 #define W83627HF_LD_WDT		0x08
74 
75 static void superio_outb(int reg, int val)
76 {
77 	outb(reg, WDT_EFER);
78 	outb(val, WDT_EFDR);
79 }
80 
81 static inline int superio_inb(int reg)
82 {
83 	outb(reg, WDT_EFER);
84 	return inb(WDT_EFDR);
85 }
86 
87 static int superio_enter(void)
88 {
89 	if (!request_muxed_region(wdt_io, 2, WATCHDOG_NAME))
90 		return -EBUSY;
91 
92 	outb_p(0x87, WDT_EFER); /* Enter extended function mode */
93 	outb_p(0x87, WDT_EFER); /* Again according to manual */
94 
95 	return 0;
96 }
97 
98 static void superio_select(int ld)
99 {
100 	superio_outb(0x07, ld);
101 }
102 
103 static void superio_exit(void)
104 {
105 	outb_p(0xAA, WDT_EFER); /* Leave extended function mode */
106 	release_region(wdt_io, 2);
107 }
108 
109 /* tyan motherboards seem to set F5 to 0x4C ?
110  * So explicitly init to appropriate value. */
111 
112 static int w83627hf_init(struct watchdog_device *wdog)
113 {
114 	int ret;
115 	unsigned char t;
116 
117 	ret = superio_enter();
118 	if (ret)
119 		return ret;
120 
121 	superio_select(W83627HF_LD_WDT);
122 	t = superio_inb(0x20);	/* check chip version	*/
123 	if (t == 0x82) {	/* W83627THF		*/
124 		t = (superio_inb(0x2b) & 0xf7);
125 		superio_outb(0x2b, t | 0x04); /* set GPIO3 to WDT0 */
126 	} else if (t == 0x88 || t == 0xa0) {	/* W83627EHF / W83627DHG */
127 		t = superio_inb(0x2d);
128 		superio_outb(0x2d, t & ~0x01);	/* set GPIO5 to WDT0 */
129 	}
130 
131 	/* set CR30 bit 0 to activate GPIO2 */
132 	t = superio_inb(0x30);
133 	if (!(t & 0x01))
134 		superio_outb(0x30, t | 0x01);
135 
136 	t = superio_inb(0xF6);
137 	if (t != 0) {
138 		pr_info("Watchdog already running. Resetting timeout to %d sec\n",
139 			wdog->timeout);
140 		superio_outb(0xF6, wdog->timeout);
141 	}
142 
143 	/* set second mode & disable keyboard turning off watchdog */
144 	t = superio_inb(0xF5) & ~0x0C;
145 	/* enable the WDTO# output low pulse to the KBRST# pin */
146 	t |= 0x02;
147 	superio_outb(0xF5, t);
148 
149 	/* disable keyboard & mouse turning off watchdog */
150 	t = superio_inb(0xF7) & ~0xC0;
151 	superio_outb(0xF7, t);
152 
153 	superio_exit();
154 
155 	return 0;
156 }
157 
158 static int wdt_set_time(unsigned int timeout)
159 {
160 	int ret;
161 
162 	ret = superio_enter();
163 	if (ret)
164 		return ret;
165 
166 	superio_select(W83627HF_LD_WDT);
167 	superio_outb(0xF6, timeout);
168 	superio_exit();
169 
170 	return 0;
171 }
172 
173 static int wdt_start(struct watchdog_device *wdog)
174 {
175 	return wdt_set_time(wdog->timeout);
176 }
177 
178 static int wdt_stop(struct watchdog_device *wdog)
179 {
180 	return wdt_set_time(0);
181 }
182 
183 static int wdt_set_timeout(struct watchdog_device *wdog, unsigned int timeout)
184 {
185 	wdog->timeout = timeout;
186 
187 	return 0;
188 }
189 
190 static unsigned int wdt_get_time(struct watchdog_device *wdog)
191 {
192 	unsigned int timeleft;
193 	int ret;
194 
195 	ret = superio_enter();
196 	if (ret)
197 		return 0;
198 
199 	superio_select(W83627HF_LD_WDT);
200 	timeleft = superio_inb(0xF6);
201 	superio_exit();
202 
203 	return timeleft;
204 }
205 
206 /*
207  *	Notifier for system down
208  */
209 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
210 	void *unused)
211 {
212 	if (code == SYS_DOWN || code == SYS_HALT)
213 		wdt_set_time(0);	/* Turn the WDT off */
214 
215 	return NOTIFY_DONE;
216 }
217 
218 /*
219  *	Kernel Interfaces
220  */
221 
222 static struct watchdog_info wdt_info = {
223 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
224 	.identity = "W83627HF Watchdog",
225 };
226 
227 static struct watchdog_ops wdt_ops = {
228 	.owner = THIS_MODULE,
229 	.start = wdt_start,
230 	.stop = wdt_stop,
231 	.set_timeout = wdt_set_timeout,
232 	.get_timeleft = wdt_get_time,
233 };
234 
235 static struct watchdog_device wdt_dev = {
236 	.info = &wdt_info,
237 	.ops = &wdt_ops,
238 	.timeout = WATCHDOG_TIMEOUT,
239 	.min_timeout = 1,
240 	.max_timeout = 255,
241 };
242 
243 /*
244  *	The WDT needs to learn about soft shutdowns in order to
245  *	turn the timebomb registers off.
246  */
247 
248 static struct notifier_block wdt_notifier = {
249 	.notifier_call = wdt_notify_sys,
250 };
251 
252 static int __init wdt_init(void)
253 {
254 	int ret;
255 
256 	pr_info("WDT driver for the Winbond(TM) W83627HF/THF/HG/DHG Super I/O chip initialising\n");
257 
258 	watchdog_init_timeout(&wdt_dev, timeout, NULL);
259 	watchdog_set_nowayout(&wdt_dev, nowayout);
260 
261 	ret = w83627hf_init(&wdt_dev);
262 	if (ret) {
263 		pr_err("failed to initialize watchdog (err=%d)\n", ret);
264 		return ret;
265 	}
266 
267 	ret = register_reboot_notifier(&wdt_notifier);
268 	if (ret != 0) {
269 		pr_err("cannot register reboot notifier (err=%d)\n", ret);
270 		return ret;
271 	}
272 
273 	ret = watchdog_register_device(&wdt_dev);
274 	if (ret)
275 		goto unreg_reboot;
276 
277 	pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
278 		wdt_dev.timeout, nowayout);
279 
280 	return ret;
281 
282 unreg_reboot:
283 	unregister_reboot_notifier(&wdt_notifier);
284 	return ret;
285 }
286 
287 static void __exit wdt_exit(void)
288 {
289 	watchdog_unregister_device(&wdt_dev);
290 	unregister_reboot_notifier(&wdt_notifier);
291 }
292 
293 module_init(wdt_init);
294 module_exit(wdt_exit);
295 
296 MODULE_LICENSE("GPL");
297 MODULE_AUTHOR("Pádraig  Brady <P@draigBrady.com>");
298 MODULE_DESCRIPTION("w83627hf/thf WDT driver");
299