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/dhg 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 || c == 0xa0) {	/* W83627EHF / W83627DHG */
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 	t |= 0x02;		  /* enable the WDTO# output low pulse
133 				    to the KBRST# pin (PIN60) */
134 	outb_p(t, WDT_EFDR);    /* Write back to CRF5 */
135 
136 	outb_p(0xF7, WDT_EFER); /* Select CRF7 */
137 	t = inb_p(WDT_EFDR);      /* read CRF7 */
138 	t &= ~0xC0;               /* disable keyboard & mouse turning off
139 				    watchdog */
140 	outb_p(t, WDT_EFDR);    /* Write back to CRF7 */
141 
142 	w83627hf_unselect_wd_register();
143 }
144 
145 static void wdt_ctrl(int timeout)
146 {
147 	spin_lock(&io_lock);
148 
149 	w83627hf_select_wd_register();
150 
151 	outb_p(0xF6, WDT_EFER);    /* Select CRF6 */
152 	outb_p(timeout, WDT_EFDR); /* Write Timeout counter to CRF6 */
153 
154 	w83627hf_unselect_wd_register();
155 
156 	spin_unlock(&io_lock);
157 }
158 
159 static int wdt_ping(void)
160 {
161 	wdt_ctrl(timeout);
162 	return 0;
163 }
164 
165 static int wdt_disable(void)
166 {
167 	wdt_ctrl(0);
168 	return 0;
169 }
170 
171 static int wdt_set_heartbeat(int t)
172 {
173 	if (t < 1 || t > 255)
174 		return -EINVAL;
175 	timeout = t;
176 	return 0;
177 }
178 
179 static ssize_t wdt_write(struct file *file, const char __user *buf,
180 						size_t count, loff_t *ppos)
181 {
182 	if (count) {
183 		if (!nowayout) {
184 			size_t i;
185 
186 			expect_close = 0;
187 
188 			for (i = 0; i != count; i++) {
189 				char c;
190 				if (get_user(c, buf + i))
191 					return -EFAULT;
192 				if (c == 'V')
193 					expect_close = 42;
194 			}
195 		}
196 		wdt_ping();
197 	}
198 	return count;
199 }
200 
201 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
202 {
203 	void __user *argp = (void __user *)arg;
204 	int __user *p = argp;
205 	int new_timeout;
206 	static const struct watchdog_info ident = {
207 		.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
208 							WDIOF_MAGICCLOSE,
209 		.firmware_version = 1,
210 		.identity = "W83627HF WDT",
211 	};
212 
213 	switch (cmd) {
214 	case WDIOC_GETSUPPORT:
215 		if (copy_to_user(argp, &ident, sizeof(ident)))
216 			return -EFAULT;
217 		break;
218 	case WDIOC_GETSTATUS:
219 	case WDIOC_GETBOOTSTATUS:
220 		return put_user(0, p);
221 	case WDIOC_SETOPTIONS:
222 	{
223 		int options, retval = -EINVAL;
224 
225 		if (get_user(options, p))
226 			return -EFAULT;
227 		if (options & WDIOS_DISABLECARD) {
228 			wdt_disable();
229 			retval = 0;
230 		}
231 		if (options & WDIOS_ENABLECARD) {
232 			wdt_ping();
233 			retval = 0;
234 		}
235 		return retval;
236 	}
237 	case WDIOC_KEEPALIVE:
238 		wdt_ping();
239 		break;
240 	case WDIOC_SETTIMEOUT:
241 		if (get_user(new_timeout, p))
242 			return -EFAULT;
243 		if (wdt_set_heartbeat(new_timeout))
244 			return -EINVAL;
245 		wdt_ping();
246 		/* Fall */
247 	case WDIOC_GETTIMEOUT:
248 		return put_user(timeout, p);
249 	default:
250 		return -ENOTTY;
251 	}
252 	return 0;
253 }
254 
255 static int wdt_open(struct inode *inode, struct file *file)
256 {
257 	if (test_and_set_bit(0, &wdt_is_open))
258 		return -EBUSY;
259 	/*
260 	 *	Activate
261 	 */
262 
263 	wdt_ping();
264 	return nonseekable_open(inode, file);
265 }
266 
267 static int wdt_close(struct inode *inode, struct file *file)
268 {
269 	if (expect_close == 42)
270 		wdt_disable();
271 	else {
272 		printk(KERN_CRIT PFX
273 			"Unexpected close, not stopping watchdog!\n");
274 		wdt_ping();
275 	}
276 	expect_close = 0;
277 	clear_bit(0, &wdt_is_open);
278 	return 0;
279 }
280 
281 /*
282  *	Notifier for system down
283  */
284 
285 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
286 	void *unused)
287 {
288 	if (code == SYS_DOWN || code == SYS_HALT)
289 		wdt_disable();	/* Turn the WDT off */
290 
291 	return NOTIFY_DONE;
292 }
293 
294 /*
295  *	Kernel Interfaces
296  */
297 
298 static const struct file_operations wdt_fops = {
299 	.owner		= THIS_MODULE,
300 	.llseek		= no_llseek,
301 	.write		= wdt_write,
302 	.unlocked_ioctl	= wdt_ioctl,
303 	.open		= wdt_open,
304 	.release	= wdt_close,
305 };
306 
307 static struct miscdevice wdt_miscdev = {
308 	.minor = WATCHDOG_MINOR,
309 	.name = "watchdog",
310 	.fops = &wdt_fops,
311 };
312 
313 /*
314  *	The WDT needs to learn about soft shutdowns in order to
315  *	turn the timebomb registers off.
316  */
317 
318 static struct notifier_block wdt_notifier = {
319 	.notifier_call = wdt_notify_sys,
320 };
321 
322 static int __init wdt_init(void)
323 {
324 	int ret;
325 
326 	printk(KERN_INFO "WDT driver for the Winbond(TM) W83627HF/THF/HG/DHG Super I/O chip initialising.\n");
327 
328 	if (wdt_set_heartbeat(timeout)) {
329 		wdt_set_heartbeat(WATCHDOG_TIMEOUT);
330 		printk(KERN_INFO PFX
331 		     "timeout value must be 1 <= timeout <= 255, using %d\n",
332 				WATCHDOG_TIMEOUT);
333 	}
334 
335 	if (!request_region(wdt_io, 1, WATCHDOG_NAME)) {
336 		printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
337 			wdt_io);
338 		ret = -EIO;
339 		goto out;
340 	}
341 
342 	w83627hf_init();
343 
344 	ret = register_reboot_notifier(&wdt_notifier);
345 	if (ret != 0) {
346 		printk(KERN_ERR PFX
347 			"cannot register reboot notifier (err=%d)\n", ret);
348 		goto unreg_regions;
349 	}
350 
351 	ret = misc_register(&wdt_miscdev);
352 	if (ret != 0) {
353 		printk(KERN_ERR PFX
354 			"cannot register miscdev on minor=%d (err=%d)\n",
355 							WATCHDOG_MINOR, ret);
356 		goto unreg_reboot;
357 	}
358 
359 	printk(KERN_INFO PFX
360 			"initialized. timeout=%d sec (nowayout=%d)\n",
361 							timeout, nowayout);
362 
363 out:
364 	return ret;
365 unreg_reboot:
366 	unregister_reboot_notifier(&wdt_notifier);
367 unreg_regions:
368 	release_region(wdt_io, 1);
369 	goto out;
370 }
371 
372 static void __exit wdt_exit(void)
373 {
374 	misc_deregister(&wdt_miscdev);
375 	unregister_reboot_notifier(&wdt_notifier);
376 	release_region(wdt_io, 1);
377 }
378 
379 module_init(wdt_init);
380 module_exit(wdt_exit);
381 
382 MODULE_LICENSE("GPL");
383 MODULE_AUTHOR("P�draig Brady <P@draigBrady.com>");
384 MODULE_DESCRIPTION("w83627hf/thf WDT driver");
385 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
386