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 	} else if (c == 0x88) {	/* W83627EHF */
93 		outb_p(0x2d, WDT_EFER); /* select GPIO5 */
94 		c = inb_p(WDT_EFDR) & ~0x01; /* PIN77 -> WDT0# */
95 		outb_p(0x2d, WDT_EFER);
96 		outb_p(c, WDT_EFDR); /* set GPIO5 to WDT0 */
97 	}
98 
99 	outb_p(0x07, WDT_EFER); /* point to logical device number reg */
100 	outb_p(0x08, WDT_EFDR); /* select logical device 8 (GPIO2) */
101 	outb_p(0x30, WDT_EFER); /* select CR30 */
102 	outb_p(0x01, WDT_EFDR); /* set bit 0 to activate GPIO2 */
103 }
104 
105 static void w83627hf_unselect_wd_register(void)
106 {
107 	outb_p(0xAA, WDT_EFER); /* Leave extended function mode */
108 }
109 
110 /* tyan motherboards seem to set F5 to 0x4C ?
111  * So explicitly init to appropriate value. */
112 
113 static void w83627hf_init(void)
114 {
115 	unsigned char t;
116 
117 	w83627hf_select_wd_register();
118 
119 	outb_p(0xF6, WDT_EFER); /* Select CRF6 */
120 	t = inb_p(WDT_EFDR);      /* read CRF6 */
121 	if (t != 0) {
122 		printk(KERN_INFO PFX
123 		     "Watchdog already running. Resetting timeout to %d sec\n",
124 								timeout);
125 		outb_p(timeout, WDT_EFDR);    /* Write back to CRF6 */
126 	}
127 
128 	outb_p(0xF5, WDT_EFER); /* Select CRF5 */
129 	t = inb_p(WDT_EFDR);      /* read CRF5 */
130 	t &= ~0x0C;               /* set second mode & disable keyboard
131 				    turning off watchdog */
132 	outb_p(t, WDT_EFDR);    /* Write back to CRF5 */
133 
134 	outb_p(0xF7, WDT_EFER); /* Select CRF7 */
135 	t = inb_p(WDT_EFDR);      /* read CRF7 */
136 	t &= ~0xC0;               /* disable keyboard & mouse turning off
137 				    watchdog */
138 	outb_p(t, WDT_EFDR);    /* Write back to CRF7 */
139 
140 	w83627hf_unselect_wd_register();
141 }
142 
143 static void wdt_ctrl(int timeout)
144 {
145 	spin_lock(&io_lock);
146 
147 	w83627hf_select_wd_register();
148 
149 	outb_p(0xF6, WDT_EFER);    /* Select CRF6 */
150 	outb_p(timeout, WDT_EFDR); /* Write Timeout counter to CRF6 */
151 
152 	w83627hf_unselect_wd_register();
153 
154 	spin_unlock(&io_lock);
155 }
156 
157 static int wdt_ping(void)
158 {
159 	wdt_ctrl(timeout);
160 	return 0;
161 }
162 
163 static int wdt_disable(void)
164 {
165 	wdt_ctrl(0);
166 	return 0;
167 }
168 
169 static int wdt_set_heartbeat(int t)
170 {
171 	if (t < 1 || t > 255)
172 		return -EINVAL;
173 	timeout = t;
174 	return 0;
175 }
176 
177 static ssize_t wdt_write(struct file *file, const char __user *buf,
178 						size_t count, loff_t *ppos)
179 {
180 	if (count) {
181 		if (!nowayout) {
182 			size_t i;
183 
184 			expect_close = 0;
185 
186 			for (i = 0; i != count; i++) {
187 				char c;
188 				if (get_user(c, buf + i))
189 					return -EFAULT;
190 				if (c == 'V')
191 					expect_close = 42;
192 			}
193 		}
194 		wdt_ping();
195 	}
196 	return count;
197 }
198 
199 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
200 {
201 	void __user *argp = (void __user *)arg;
202 	int __user *p = argp;
203 	int new_timeout;
204 	static struct watchdog_info ident = {
205 		.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
206 							WDIOF_MAGICCLOSE,
207 		.firmware_version = 1,
208 		.identity = "W83627HF WDT",
209 	};
210 
211 	switch (cmd) {
212 	case WDIOC_GETSUPPORT:
213 		if (copy_to_user(argp, &ident, sizeof(ident)))
214 			return -EFAULT;
215 		break;
216 	case WDIOC_GETSTATUS:
217 	case WDIOC_GETBOOTSTATUS:
218 		return put_user(0, p);
219 	case WDIOC_SETOPTIONS:
220 	{
221 		int options, retval = -EINVAL;
222 
223 		if (get_user(options, p))
224 			return -EFAULT;
225 		if (options & WDIOS_DISABLECARD) {
226 			wdt_disable();
227 			retval = 0;
228 		}
229 		if (options & WDIOS_ENABLECARD) {
230 			wdt_ping();
231 			retval = 0;
232 		}
233 		return retval;
234 	}
235 	case WDIOC_KEEPALIVE:
236 		wdt_ping();
237 		break;
238 	case WDIOC_SETTIMEOUT:
239 		if (get_user(new_timeout, p))
240 			return -EFAULT;
241 		if (wdt_set_heartbeat(new_timeout))
242 			return -EINVAL;
243 		wdt_ping();
244 		/* Fall */
245 	case WDIOC_GETTIMEOUT:
246 		return put_user(timeout, p);
247 	default:
248 		return -ENOTTY;
249 	}
250 	return 0;
251 }
252 
253 static int wdt_open(struct inode *inode, struct file *file)
254 {
255 	if (test_and_set_bit(0, &wdt_is_open))
256 		return -EBUSY;
257 	/*
258 	 *	Activate
259 	 */
260 
261 	wdt_ping();
262 	return nonseekable_open(inode, file);
263 }
264 
265 static int wdt_close(struct inode *inode, struct file *file)
266 {
267 	if (expect_close == 42)
268 		wdt_disable();
269 	else {
270 		printk(KERN_CRIT PFX
271 			"Unexpected close, not stopping watchdog!\n");
272 		wdt_ping();
273 	}
274 	expect_close = 0;
275 	clear_bit(0, &wdt_is_open);
276 	return 0;
277 }
278 
279 /*
280  *	Notifier for system down
281  */
282 
283 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
284 	void *unused)
285 {
286 	if (code == SYS_DOWN || code == SYS_HALT)
287 		wdt_disable();	/* Turn the WDT off */
288 
289 	return NOTIFY_DONE;
290 }
291 
292 /*
293  *	Kernel Interfaces
294  */
295 
296 static const struct file_operations wdt_fops = {
297 	.owner		= THIS_MODULE,
298 	.llseek		= no_llseek,
299 	.write		= wdt_write,
300 	.unlocked_ioctl	= wdt_ioctl,
301 	.open		= wdt_open,
302 	.release	= wdt_close,
303 };
304 
305 static struct miscdevice wdt_miscdev = {
306 	.minor = WATCHDOG_MINOR,
307 	.name = "watchdog",
308 	.fops = &wdt_fops,
309 };
310 
311 /*
312  *	The WDT needs to learn about soft shutdowns in order to
313  *	turn the timebomb registers off.
314  */
315 
316 static struct notifier_block wdt_notifier = {
317 	.notifier_call = wdt_notify_sys,
318 };
319 
320 static int __init wdt_init(void)
321 {
322 	int ret;
323 
324 	printk(KERN_INFO "WDT driver for the Winbond(TM) W83627HF/THF/HG Super I/O chip initialising.\n");
325 
326 	if (wdt_set_heartbeat(timeout)) {
327 		wdt_set_heartbeat(WATCHDOG_TIMEOUT);
328 		printk(KERN_INFO PFX
329 		     "timeout value must be 1 <= timeout <= 255, using %d\n",
330 				WATCHDOG_TIMEOUT);
331 	}
332 
333 	if (!request_region(wdt_io, 1, WATCHDOG_NAME)) {
334 		printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
335 			wdt_io);
336 		ret = -EIO;
337 		goto out;
338 	}
339 
340 	w83627hf_init();
341 
342 	ret = register_reboot_notifier(&wdt_notifier);
343 	if (ret != 0) {
344 		printk(KERN_ERR PFX
345 			"cannot register reboot notifier (err=%d)\n", ret);
346 		goto unreg_regions;
347 	}
348 
349 	ret = misc_register(&wdt_miscdev);
350 	if (ret != 0) {
351 		printk(KERN_ERR PFX
352 			"cannot register miscdev on minor=%d (err=%d)\n",
353 							WATCHDOG_MINOR, ret);
354 		goto unreg_reboot;
355 	}
356 
357 	printk(KERN_INFO PFX
358 			"initialized. timeout=%d sec (nowayout=%d)\n",
359 							timeout, nowayout);
360 
361 out:
362 	return ret;
363 unreg_reboot:
364 	unregister_reboot_notifier(&wdt_notifier);
365 unreg_regions:
366 	release_region(wdt_io, 1);
367 	goto out;
368 }
369 
370 static void __exit wdt_exit(void)
371 {
372 	misc_deregister(&wdt_miscdev);
373 	unregister_reboot_notifier(&wdt_notifier);
374 	release_region(wdt_io, 1);
375 }
376 
377 module_init(wdt_init);
378 module_exit(wdt_exit);
379 
380 MODULE_LICENSE("GPL");
381 MODULE_AUTHOR("P�draig Brady <P@draigBrady.com>");
382 MODULE_DESCRIPTION("w83627hf/thf WDT driver");
383 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
384