1 /*
2  *	w83627hf/thf WDT driver
3  *
4  *	(c) Copyright 2007 Vlad Drukker <vlad@storewiz.com>
5  *		added support for W83627THF.
6  *
7  *	(c) Copyright 2003,2007 P�draig Brady <P@draigBrady.com>
8  *
9  *	Based on advantechwdt.c which is based on wdt.c.
10  *	Original copyright messages:
11  *
12  *	(c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
13  *
14  *	(c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
15  *						All Rights Reserved.
16  *
17  *	This program is free software; you can redistribute it and/or
18  *	modify it under the terms of the GNU General Public License
19  *	as published by the Free Software Foundation; either version
20  *	2 of the License, or (at your option) any later version.
21  *
22  *	Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
23  *	warranty for any of this software. This material is provided
24  *	"AS-IS" and at no charge.
25  *
26  *	(c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>
27  */
28 
29 #include <linux/module.h>
30 #include <linux/moduleparam.h>
31 #include <linux/types.h>
32 #include <linux/miscdevice.h>
33 #include <linux/watchdog.h>
34 #include <linux/fs.h>
35 #include <linux/ioport.h>
36 #include <linux/notifier.h>
37 #include <linux/reboot.h>
38 #include <linux/init.h>
39 #include <linux/spinlock.h>
40 #include <linux/io.h>
41 #include <linux/uaccess.h>
42 
43 #include <asm/system.h>
44 
45 #define WATCHDOG_NAME "w83627hf/thf/hg WDT"
46 #define PFX WATCHDOG_NAME ": "
47 #define WATCHDOG_TIMEOUT 60		/* 60 sec default timeout */
48 
49 static unsigned long wdt_is_open;
50 static char expect_close;
51 static DEFINE_SPINLOCK(io_lock);
52 
53 /* You must set this - there is no sane way to probe for this board. */
54 static int wdt_io = 0x2E;
55 module_param(wdt_io, int, 0);
56 MODULE_PARM_DESC(wdt_io, "w83627hf/thf WDT io port (default 0x2E)");
57 
58 static int timeout = WATCHDOG_TIMEOUT;	/* in seconds */
59 module_param(timeout, int, 0);
60 MODULE_PARM_DESC(timeout,
61 		"Watchdog timeout in seconds. 1 <= timeout <= 255, default="
62 				__MODULE_STRING(WATCHDOG_TIMEOUT) ".");
63 
64 static int nowayout = WATCHDOG_NOWAYOUT;
65 module_param(nowayout, int, 0);
66 MODULE_PARM_DESC(nowayout,
67 		"Watchdog cannot be stopped once started (default="
68 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
69 
70 /*
71  *	Kernel methods.
72  */
73 
74 #define WDT_EFER (wdt_io+0)   /* Extended Function Enable Registers */
75 #define WDT_EFIR (wdt_io+0)   /* Extended Function Index Register
76 							(same as EFER) */
77 #define WDT_EFDR (WDT_EFIR+1) /* Extended Function Data Register */
78 
79 static void w83627hf_select_wd_register(void)
80 {
81 	unsigned char c;
82 	outb_p(0x87, WDT_EFER); /* Enter extended function mode */
83 	outb_p(0x87, WDT_EFER); /* Again according to manual */
84 
85 	outb(0x20, WDT_EFER);	/* check chip version	*/
86 	c = inb(WDT_EFDR);
87 	if (c == 0x82) {	/* W83627THF		*/
88 		outb_p(0x2b, WDT_EFER); /* select GPIO3 */
89 		c = ((inb_p(WDT_EFDR) & 0xf7) | 0x04); /* select WDT0 */
90 		outb_p(0x2b, WDT_EFER);
91 		outb_p(c, WDT_EFDR);	/* set GPIO3 to WDT0 */
92 	}
93 
94 	outb_p(0x07, WDT_EFER); /* point to logical device number reg */
95 	outb_p(0x08, WDT_EFDR); /* select logical device 8 (GPIO2) */
96 	outb_p(0x30, WDT_EFER); /* select CR30 */
97 	outb_p(0x01, WDT_EFDR); /* set bit 0 to activate GPIO2 */
98 }
99 
100 static void w83627hf_unselect_wd_register(void)
101 {
102 	outb_p(0xAA, WDT_EFER); /* Leave extended function mode */
103 }
104 
105 /* tyan motherboards seem to set F5 to 0x4C ?
106  * So explicitly init to appropriate value. */
107 
108 static void w83627hf_init(void)
109 {
110 	unsigned char t;
111 
112 	w83627hf_select_wd_register();
113 
114 	outb_p(0xF6, WDT_EFER); /* Select CRF6 */
115 	t = inb_p(WDT_EFDR);      /* read CRF6 */
116 	if (t != 0) {
117 		printk(KERN_INFO PFX
118 		     "Watchdog already running. Resetting timeout to %d sec\n",
119 								timeout);
120 		outb_p(timeout, WDT_EFDR);    /* Write back to CRF6 */
121 	}
122 
123 	outb_p(0xF5, WDT_EFER); /* Select CRF5 */
124 	t = inb_p(WDT_EFDR);      /* read CRF5 */
125 	t &= ~0x0C;               /* set second mode & disable keyboard
126 				    turning off watchdog */
127 	outb_p(t, WDT_EFDR);    /* Write back to CRF5 */
128 
129 	outb_p(0xF7, WDT_EFER); /* Select CRF7 */
130 	t = inb_p(WDT_EFDR);      /* read CRF7 */
131 	t &= ~0xC0;               /* disable keyboard & mouse turning off
132 				    watchdog */
133 	outb_p(t, WDT_EFDR);    /* Write back to CRF7 */
134 
135 	w83627hf_unselect_wd_register();
136 }
137 
138 static void wdt_ctrl(int timeout)
139 {
140 	spin_lock(&io_lock);
141 
142 	w83627hf_select_wd_register();
143 
144 	outb_p(0xF6, WDT_EFER);    /* Select CRF6 */
145 	outb_p(timeout, WDT_EFDR); /* Write Timeout counter to CRF6 */
146 
147 	w83627hf_unselect_wd_register();
148 
149 	spin_unlock(&io_lock);
150 }
151 
152 static int wdt_ping(void)
153 {
154 	wdt_ctrl(timeout);
155 	return 0;
156 }
157 
158 static int wdt_disable(void)
159 {
160 	wdt_ctrl(0);
161 	return 0;
162 }
163 
164 static int wdt_set_heartbeat(int t)
165 {
166 	if (t < 1 || t > 255)
167 		return -EINVAL;
168 	timeout = t;
169 	return 0;
170 }
171 
172 static ssize_t wdt_write(struct file *file, const char __user *buf,
173 						size_t count, loff_t *ppos)
174 {
175 	if (count) {
176 		if (!nowayout) {
177 			size_t i;
178 
179 			expect_close = 0;
180 
181 			for (i = 0; i != count; i++) {
182 				char c;
183 				if (get_user(c, buf + i))
184 					return -EFAULT;
185 				if (c == 'V')
186 					expect_close = 42;
187 			}
188 		}
189 		wdt_ping();
190 	}
191 	return count;
192 }
193 
194 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
195 {
196 	void __user *argp = (void __user *)arg;
197 	int __user *p = argp;
198 	int new_timeout;
199 	static struct watchdog_info ident = {
200 		.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
201 							WDIOF_MAGICCLOSE,
202 		.firmware_version = 1,
203 		.identity = "W83627HF WDT",
204 	};
205 
206 	switch (cmd) {
207 	case WDIOC_GETSUPPORT:
208 		if (copy_to_user(argp, &ident, sizeof(ident)))
209 			return -EFAULT;
210 		break;
211 	case WDIOC_GETSTATUS:
212 	case WDIOC_GETBOOTSTATUS:
213 		return put_user(0, p);
214 	case WDIOC_SETOPTIONS:
215 	{
216 		int options, retval = -EINVAL;
217 
218 		if (get_user(options, p))
219 			return -EFAULT;
220 		if (options & WDIOS_DISABLECARD) {
221 			wdt_disable();
222 			retval = 0;
223 		}
224 		if (options & WDIOS_ENABLECARD) {
225 			wdt_ping();
226 			retval = 0;
227 		}
228 		return retval;
229 	}
230 	case WDIOC_KEEPALIVE:
231 		wdt_ping();
232 		break;
233 	case WDIOC_SETTIMEOUT:
234 		if (get_user(new_timeout, p))
235 			return -EFAULT;
236 		if (wdt_set_heartbeat(new_timeout))
237 			return -EINVAL;
238 		wdt_ping();
239 		/* Fall */
240 	case WDIOC_GETTIMEOUT:
241 		return put_user(timeout, p);
242 	default:
243 		return -ENOTTY;
244 	}
245 	return 0;
246 }
247 
248 static int wdt_open(struct inode *inode, struct file *file)
249 {
250 	if (test_and_set_bit(0, &wdt_is_open))
251 		return -EBUSY;
252 	/*
253 	 *	Activate
254 	 */
255 
256 	wdt_ping();
257 	return nonseekable_open(inode, file);
258 }
259 
260 static int wdt_close(struct inode *inode, struct file *file)
261 {
262 	if (expect_close == 42)
263 		wdt_disable();
264 	else {
265 		printk(KERN_CRIT PFX
266 			"Unexpected close, not stopping watchdog!\n");
267 		wdt_ping();
268 	}
269 	expect_close = 0;
270 	clear_bit(0, &wdt_is_open);
271 	return 0;
272 }
273 
274 /*
275  *	Notifier for system down
276  */
277 
278 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
279 	void *unused)
280 {
281 	if (code == SYS_DOWN || code == SYS_HALT)
282 		wdt_disable();	/* Turn the WDT off */
283 
284 	return NOTIFY_DONE;
285 }
286 
287 /*
288  *	Kernel Interfaces
289  */
290 
291 static const struct file_operations wdt_fops = {
292 	.owner		= THIS_MODULE,
293 	.llseek		= no_llseek,
294 	.write		= wdt_write,
295 	.unlocked_ioctl	= wdt_ioctl,
296 	.open		= wdt_open,
297 	.release	= wdt_close,
298 };
299 
300 static struct miscdevice wdt_miscdev = {
301 	.minor = WATCHDOG_MINOR,
302 	.name = "watchdog",
303 	.fops = &wdt_fops,
304 };
305 
306 /*
307  *	The WDT needs to learn about soft shutdowns in order to
308  *	turn the timebomb registers off.
309  */
310 
311 static struct notifier_block wdt_notifier = {
312 	.notifier_call = wdt_notify_sys,
313 };
314 
315 static int __init wdt_init(void)
316 {
317 	int ret;
318 
319 	printk(KERN_INFO "WDT driver for the Winbond(TM) W83627HF/THF/HG Super I/O chip initialising.\n");
320 
321 	if (wdt_set_heartbeat(timeout)) {
322 		wdt_set_heartbeat(WATCHDOG_TIMEOUT);
323 		printk(KERN_INFO PFX
324 		     "timeout value must be 1 <= timeout <= 255, using %d\n",
325 				WATCHDOG_TIMEOUT);
326 	}
327 
328 	if (!request_region(wdt_io, 1, WATCHDOG_NAME)) {
329 		printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
330 			wdt_io);
331 		ret = -EIO;
332 		goto out;
333 	}
334 
335 	w83627hf_init();
336 
337 	ret = register_reboot_notifier(&wdt_notifier);
338 	if (ret != 0) {
339 		printk(KERN_ERR PFX
340 			"cannot register reboot notifier (err=%d)\n", ret);
341 		goto unreg_regions;
342 	}
343 
344 	ret = misc_register(&wdt_miscdev);
345 	if (ret != 0) {
346 		printk(KERN_ERR PFX
347 			"cannot register miscdev on minor=%d (err=%d)\n",
348 							WATCHDOG_MINOR, ret);
349 		goto unreg_reboot;
350 	}
351 
352 	printk(KERN_INFO PFX
353 			"initialized. timeout=%d sec (nowayout=%d)\n",
354 							timeout, nowayout);
355 
356 out:
357 	return ret;
358 unreg_reboot:
359 	unregister_reboot_notifier(&wdt_notifier);
360 unreg_regions:
361 	release_region(wdt_io, 1);
362 	goto out;
363 }
364 
365 static void __exit wdt_exit(void)
366 {
367 	misc_deregister(&wdt_miscdev);
368 	unregister_reboot_notifier(&wdt_notifier);
369 	release_region(wdt_io, 1);
370 }
371 
372 module_init(wdt_init);
373 module_exit(wdt_exit);
374 
375 MODULE_LICENSE("GPL");
376 MODULE_AUTHOR("P�draig Brady <P@draigBrady.com>");
377 MODULE_DESCRIPTION("w83627hf/thf WDT driver");
378 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
379