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@redhat.com>, All Rights Reserved.
15  *				http://www.redhat.com
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@redhat.com>
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 
41 #include <asm/io.h>
42 #include <asm/uaccess.h>
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, "Watchdog timeout in seconds. 1<= timeout <=255, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
61 
62 static int nowayout = WATCHDOG_NOWAYOUT;
63 module_param(nowayout, int, 0);
64 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
65 
66 /*
67  *	Kernel methods.
68  */
69 
70 #define WDT_EFER (wdt_io+0)   /* Extended Function Enable Registers */
71 #define WDT_EFIR (wdt_io+0)   /* Extended Function Index Register (same as EFER) */
72 #define WDT_EFDR (WDT_EFIR+1) /* Extended Function Data Register */
73 
74 static void
75 w83627hf_select_wd_register(void)
76 {
77 	unsigned char c;
78 	outb_p(0x87, WDT_EFER); /* Enter extended function mode */
79 	outb_p(0x87, WDT_EFER); /* Again according to manual */
80 
81 	outb(0x20, WDT_EFER);	/* check chip version	*/
82 	c = inb(WDT_EFDR);
83 	if (c == 0x82) {	/* W83627THF		*/
84 		outb_p(0x2b, WDT_EFER); /* select GPIO3 */
85 		c = ((inb_p(WDT_EFDR) & 0xf7) | 0x04); /* select WDT0 */
86 		outb_p(0x2b, WDT_EFER);
87 		outb_p(c, WDT_EFDR);	/* set GPIO3 to WDT0 */
88 	}
89 
90 	outb_p(0x07, WDT_EFER); /* point to logical device number reg */
91 	outb_p(0x08, WDT_EFDR); /* select logical device 8 (GPIO2) */
92 	outb_p(0x30, WDT_EFER); /* select CR30 */
93 	outb_p(0x01, WDT_EFDR); /* set bit 0 to activate GPIO2 */
94 }
95 
96 static void
97 w83627hf_unselect_wd_register(void)
98 {
99 	outb_p(0xAA, WDT_EFER); /* Leave extended function mode */
100 }
101 
102 /* tyan motherboards seem to set F5 to 0x4C ?
103  * So explicitly init to appropriate value. */
104 static void
105 w83627hf_init(void)
106 {
107 	unsigned char t;
108 
109 	w83627hf_select_wd_register();
110 
111 	outb_p(0xF6, WDT_EFER); /* Select CRF6 */
112 	t=inb_p(WDT_EFDR);      /* read CRF6 */
113 	if (t != 0) {
114 		printk (KERN_INFO PFX "Watchdog already running. Resetting timeout to %d sec\n", timeout);
115 		outb_p(timeout, WDT_EFDR);    /* Write back to CRF6 */
116 	}
117 
118 	outb_p(0xF5, WDT_EFER); /* Select CRF5 */
119 	t=inb_p(WDT_EFDR);      /* read CRF5 */
120 	t&=~0x0C;               /* set second mode & disable keyboard turning off watchdog */
121 	outb_p(t, WDT_EFDR);    /* Write back to CRF5 */
122 
123 	outb_p(0xF7, WDT_EFER); /* Select CRF7 */
124 	t=inb_p(WDT_EFDR);      /* read CRF7 */
125 	t&=~0xC0;               /* disable keyboard & mouse turning off watchdog */
126 	outb_p(t, WDT_EFDR);    /* Write back to CRF7 */
127 
128 	w83627hf_unselect_wd_register();
129 }
130 
131 static void
132 wdt_ctrl(int timeout)
133 {
134 	spin_lock(&io_lock);
135 
136 	w83627hf_select_wd_register();
137 
138 	outb_p(0xF6, WDT_EFER);    /* Select CRF6 */
139 	outb_p(timeout, WDT_EFDR); /* Write Timeout counter to CRF6 */
140 
141 	w83627hf_unselect_wd_register();
142 
143 	spin_unlock(&io_lock);
144 }
145 
146 static int
147 wdt_ping(void)
148 {
149 	wdt_ctrl(timeout);
150 	return 0;
151 }
152 
153 static int
154 wdt_disable(void)
155 {
156 	wdt_ctrl(0);
157 	return 0;
158 }
159 
160 static int
161 wdt_set_heartbeat(int t)
162 {
163 	if ((t < 1) || (t > 255))
164 		return -EINVAL;
165 
166 	timeout = t;
167 	return 0;
168 }
169 
170 static ssize_t
171 wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
172 {
173 	if (count) {
174 		if (!nowayout) {
175 			size_t i;
176 
177 			expect_close = 0;
178 
179 			for (i = 0; i != count; i++) {
180 				char c;
181 				if (get_user(c, buf+i))
182 					return -EFAULT;
183 				if (c == 'V')
184 					expect_close = 42;
185 			}
186 		}
187 		wdt_ping();
188 	}
189 	return count;
190 }
191 
192 static int
193 wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
194 	  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 | WDIOF_MAGICCLOSE,
201 		.firmware_version = 1,
202 		.identity = "W83627HF WDT",
203 	};
204 
205 	switch (cmd) {
206 	case WDIOC_GETSUPPORT:
207 	  if (copy_to_user(argp, &ident, sizeof(ident)))
208 	    return -EFAULT;
209 	  break;
210 
211 	case WDIOC_GETSTATUS:
212 	case WDIOC_GETBOOTSTATUS:
213 	  return put_user(0, p);
214 
215 	case WDIOC_KEEPALIVE:
216 	  wdt_ping();
217 	  break;
218 
219 	case WDIOC_SETTIMEOUT:
220 	  if (get_user(new_timeout, p))
221 		  return -EFAULT;
222 	  if (wdt_set_heartbeat(new_timeout))
223 		  return -EINVAL;
224 	  wdt_ping();
225 	  /* Fall */
226 
227 	case WDIOC_GETTIMEOUT:
228 	  return put_user(timeout, p);
229 
230 	case WDIOC_SETOPTIONS:
231 	{
232 	  int options, retval = -EINVAL;
233 
234 	  if (get_user(options, p))
235 	    return -EFAULT;
236 
237 	  if (options & WDIOS_DISABLECARD) {
238 	    wdt_disable();
239 	    retval = 0;
240 	  }
241 
242 	  if (options & WDIOS_ENABLECARD) {
243 	    wdt_ping();
244 	    retval = 0;
245 	  }
246 
247 	  return retval;
248 	}
249 
250 	default:
251 	  return -ENOTTY;
252 	}
253 	return 0;
254 }
255 
256 static int
257 wdt_open(struct inode *inode, struct file *file)
258 {
259 	if (test_and_set_bit(0, &wdt_is_open))
260 		return -EBUSY;
261 	/*
262 	 *	Activate
263 	 */
264 
265 	wdt_ping();
266 	return nonseekable_open(inode, file);
267 }
268 
269 static int
270 wdt_close(struct inode *inode, struct file *file)
271 {
272 	if (expect_close == 42) {
273 		wdt_disable();
274 	} else {
275 		printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
276 		wdt_ping();
277 	}
278 	expect_close = 0;
279 	clear_bit(0, &wdt_is_open);
280 	return 0;
281 }
282 
283 /*
284  *	Notifier for system down
285  */
286 
287 static int
288 wdt_notify_sys(struct notifier_block *this, unsigned long code,
289 	void *unused)
290 {
291 	if (code == SYS_DOWN || code == SYS_HALT) {
292 		/* Turn the WDT off */
293 		wdt_disable();
294 	}
295 	return NOTIFY_DONE;
296 }
297 
298 /*
299  *	Kernel Interfaces
300  */
301 
302 static const struct file_operations wdt_fops = {
303 	.owner		= THIS_MODULE,
304 	.llseek		= no_llseek,
305 	.write		= wdt_write,
306 	.ioctl		= wdt_ioctl,
307 	.open		= wdt_open,
308 	.release	= wdt_close,
309 };
310 
311 static struct miscdevice wdt_miscdev = {
312 	.minor = WATCHDOG_MINOR,
313 	.name = "watchdog",
314 	.fops = &wdt_fops,
315 };
316 
317 /*
318  *	The WDT needs to learn about soft shutdowns in order to
319  *	turn the timebomb registers off.
320  */
321 
322 static struct notifier_block wdt_notifier = {
323 	.notifier_call = wdt_notify_sys,
324 };
325 
326 static int __init
327 wdt_init(void)
328 {
329 	int ret;
330 
331 	printk(KERN_INFO "WDT driver for the Winbond(TM) W83627HF/THF/HG Super I/O chip initialising.\n");
332 
333 	if (wdt_set_heartbeat(timeout)) {
334 		wdt_set_heartbeat(WATCHDOG_TIMEOUT);
335 		printk (KERN_INFO PFX "timeout value must be 1<=timeout<=255, using %d\n",
336 			WATCHDOG_TIMEOUT);
337 	}
338 
339 	if (!request_region(wdt_io, 1, WATCHDOG_NAME)) {
340 		printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
341 			wdt_io);
342 		ret = -EIO;
343 		goto out;
344 	}
345 
346 	w83627hf_init();
347 
348 	ret = register_reboot_notifier(&wdt_notifier);
349 	if (ret != 0) {
350 		printk (KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
351 			ret);
352 		goto unreg_regions;
353 	}
354 
355 	ret = misc_register(&wdt_miscdev);
356 	if (ret != 0) {
357 		printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
358 			WATCHDOG_MINOR, ret);
359 		goto unreg_reboot;
360 	}
361 
362 	printk (KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
363 		timeout, nowayout);
364 
365 out:
366 	return ret;
367 unreg_reboot:
368 	unregister_reboot_notifier(&wdt_notifier);
369 unreg_regions:
370 	release_region(wdt_io, 1);
371 	goto out;
372 }
373 
374 static void __exit
375 wdt_exit(void)
376 {
377 	misc_deregister(&wdt_miscdev);
378 	unregister_reboot_notifier(&wdt_notifier);
379 	release_region(wdt_io,1);
380 }
381 
382 module_init(wdt_init);
383 module_exit(wdt_exit);
384 
385 MODULE_LICENSE("GPL");
386 MODULE_AUTHOR("P�draig Brady <P@draigBrady.com>");
387 MODULE_DESCRIPTION("w83627hf/thf WDT driver");
388 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
389