1 /*
2 * W83877F Computer Watchdog Timer driver
3 *
4 * Based on acquirewdt.c by Alan Cox,
5 * and sbc60xxwdt.c by Jakob Oestergaard <jakob@unthought.net>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * The authors do NOT admit liability nor provide warranty for
13 * any of this software. This material is provided "AS-IS" in
14 * the hope that it may be useful for others.
15 *
16 * (c) Copyright 2001 Scott Jennings <linuxdrivers@oro.net>
17 *
18 * 4/19 - 2001 [Initial revision]
19 * 9/27 - 2001 Added spinlocking
20 * 4/12 - 2002 [rob@osinvestor.com] Eliminate extra comments
21 * Eliminate fop_read
22 * Eliminate extra spin_unlock
23 * Added KERN_* tags to printks
24 * add CONFIG_WATCHDOG_NOWAYOUT support
25 * fix possible wdt_is_open race
26 * changed watchdog_info to correctly reflect what the driver offers
27 * added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS, WDIOC_SETTIMEOUT,
28 * WDIOC_GETTIMEOUT, and WDIOC_SETOPTIONS ioctls
29 * 09/8 - 2003 [wim@iguana.be] cleanup of trailing spaces
30 * added extra printk's for startup problems
31 * use module_param
32 * made timeout (the emulated heartbeat) a module_param
33 * made the keepalive ping an internal subroutine
34 *
35 * This WDT driver is different from most other Linux WDT
36 * drivers in that the driver will ping the watchdog by itself,
37 * because this particular WDT has a very short timeout (1.6
38 * seconds) and it would be insane to count on any userspace
39 * daemon always getting scheduled within that time frame.
40 */
41
42 #include <linux/module.h>
43 #include <linux/moduleparam.h>
44 #include <linux/types.h>
45 #include <linux/timer.h>
46 #include <linux/jiffies.h>
47 #include <linux/miscdevice.h>
48 #include <linux/watchdog.h>
49 #include <linux/fs.h>
50 #include <linux/ioport.h>
51 #include <linux/notifier.h>
52 #include <linux/reboot.h>
53 #include <linux/init.h>
54 #include <asm/io.h>
55 #include <asm/uaccess.h>
56 #include <asm/system.h>
57
58 #define OUR_NAME "w83877f_wdt"
59 #define PFX OUR_NAME ": "
60
61 #define ENABLE_W83877F_PORT 0x3F0
62 #define ENABLE_W83877F 0x87
63 #define DISABLE_W83877F 0xAA
64 #define WDT_PING 0x443
65 #define WDT_REGISTER 0x14
66 #define WDT_ENABLE 0x9C
67 #define WDT_DISABLE 0x8C
68
69 /*
70 * The W83877F seems to be fixed at 1.6s timeout (at least on the
71 * EMACS PC-104 board I'm using). If we reset the watchdog every
72 * ~250ms we should be safe. */
73
74 #define WDT_INTERVAL (HZ/4+1)
75
76 /*
77 * We must not require too good response from the userspace daemon.
78 * Here we require the userspace daemon to send us a heartbeat
79 * char to /dev/watchdog every 30 seconds.
80 */
81
82 #define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */
83 static int timeout = WATCHDOG_TIMEOUT; /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
84 module_param(timeout, int, 0);
85 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
86
87
88 static int nowayout = WATCHDOG_NOWAYOUT;
89 module_param(nowayout, int, 0);
90 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
91
92 static void wdt_timer_ping(unsigned long);
93 static DEFINE_TIMER(timer, wdt_timer_ping, 0, 0);
94 static unsigned long next_heartbeat;
95 static unsigned long wdt_is_open;
96 static char wdt_expect_close;
97 static DEFINE_SPINLOCK(wdt_spinlock);
98
99 /*
100 * Whack the dog
101 */
102
103 static void wdt_timer_ping(unsigned long data)
104 {
105 /* If we got a heartbeat pulse within the WDT_US_INTERVAL
106 * we agree to ping the WDT
107 */
108 if(time_before(jiffies, next_heartbeat))
109 {
110 /* Ping the WDT */
111 spin_lock(&wdt_spinlock);
112
113 /* Ping the WDT by reading from WDT_PING */
114 inb_p(WDT_PING);
115
116 /* Re-set the timer interval */
117 mod_timer(&timer, jiffies + WDT_INTERVAL);
118
119 spin_unlock(&wdt_spinlock);
120
121 } else {
122 printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n");
123 }
124 }
125
126 /*
127 * Utility routines
128 */
129
130 static void wdt_change(int writeval)
131 {
132 unsigned long flags;
133 spin_lock_irqsave(&wdt_spinlock, flags);
134
135 /* buy some time */
136 inb_p(WDT_PING);
137
138 /* make W83877F available */
139 outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT);
140 outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT);
141
142 /* enable watchdog */
143 outb_p(WDT_REGISTER, ENABLE_W83877F_PORT);
144 outb_p(writeval, ENABLE_W83877F_PORT+1);
145
146 /* lock the W8387FF away */
147 outb_p(DISABLE_W83877F, ENABLE_W83877F_PORT);
148
149 spin_unlock_irqrestore(&wdt_spinlock, flags);
150 }
151
152 static void wdt_startup(void)
153 {
154 next_heartbeat = jiffies + (timeout * HZ);
155
156 /* Start the timer */
157 mod_timer(&timer, jiffies + WDT_INTERVAL);
158
159 wdt_change(WDT_ENABLE);
160
161 printk(KERN_INFO PFX "Watchdog timer is now enabled.\n");
162 }
163
164 static void wdt_turnoff(void)
165 {
166 /* Stop the timer */
167 del_timer(&timer);
168
169 wdt_change(WDT_DISABLE);
170
171 printk(KERN_INFO PFX "Watchdog timer is now disabled...\n");
172 }
173
174 static void wdt_keepalive(void)
175 {
176 /* user land ping */
177 next_heartbeat = jiffies + (timeout * HZ);
178 }
179
180 /*
181 * /dev/watchdog handling
182 */
183
184 static ssize_t fop_write(struct file * file, const char __user * buf, size_t count, loff_t * ppos)
185 {
186 /* See if we got the magic character 'V' and reload the timer */
187 if(count)
188 {
189 if (!nowayout)
190 {
191 size_t ofs;
192
193 /* note: just in case someone wrote the magic character
194 * five months ago... */
195 wdt_expect_close = 0;
196
197 /* scan to see whether or not we got the magic character */
198 for(ofs = 0; ofs != count; ofs++)
199 {
200 char c;
201 if (get_user(c, buf + ofs))
202 return -EFAULT;
203 if (c == 'V')
204 wdt_expect_close = 42;
205 }
206 }
207
208 /* someone wrote to us, we should restart timer */
209 wdt_keepalive();
210 }
211 return count;
212 }
213
214 static int fop_open(struct inode * inode, struct file * file)
215 {
216 /* Just in case we're already talking to someone... */
217 if(test_and_set_bit(0, &wdt_is_open))
218 return -EBUSY;
219
220 /* Good, fire up the show */
221 wdt_startup();
222 return nonseekable_open(inode, file);
223 }
224
225 static int fop_close(struct inode * inode, struct file * file)
226 {
227 if(wdt_expect_close == 42)
228 wdt_turnoff();
229 else {
230 del_timer(&timer);
231 printk(KERN_CRIT PFX "device file closed unexpectedly. Will not stop the WDT!\n");
232 }
233 clear_bit(0, &wdt_is_open);
234 wdt_expect_close = 0;
235 return 0;
236 }
237
238 static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
239 unsigned long arg)
240 {
241 void __user *argp = (void __user *)arg;
242 int __user *p = argp;
243 static struct watchdog_info ident=
244 {
245 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
246 .firmware_version = 1,
247 .identity = "W83877F",
248 };
249
250 switch(cmd)
251 {
252 default:
253 return -ENOTTY;
254 case WDIOC_GETSUPPORT:
255 return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0;
256 case WDIOC_GETSTATUS:
257 case WDIOC_GETBOOTSTATUS:
258 return put_user(0, p);
259 case WDIOC_KEEPALIVE:
260 wdt_keepalive();
261 return 0;
262 case WDIOC_SETOPTIONS:
263 {
264 int new_options, retval = -EINVAL;
265
266 if(get_user(new_options, p))
267 return -EFAULT;
268
269 if(new_options & WDIOS_DISABLECARD) {
270 wdt_turnoff();
271 retval = 0;
272 }
273
274 if(new_options & WDIOS_ENABLECARD) {
275 wdt_startup();
276 retval = 0;
277 }
278
279 return retval;
280 }
281 case WDIOC_SETTIMEOUT:
282 {
283 int new_timeout;
284
285 if(get_user(new_timeout, p))
286 return -EFAULT;
287
288 if(new_timeout < 1 || new_timeout > 3600) /* arbitrary upper limit */
289 return -EINVAL;
290
291 timeout = new_timeout;
292 wdt_keepalive();
293 /* Fall through */
294 }
295 case WDIOC_GETTIMEOUT:
296 return put_user(timeout, p);
297 }
298 }
299
300 static const struct file_operations wdt_fops = {
301 .owner = THIS_MODULE,
302 .llseek = no_llseek,
303 .write = fop_write,
304 .open = fop_open,
305 .release = fop_close,
306 .ioctl = fop_ioctl,
307 };
308
309 static struct miscdevice wdt_miscdev = {
310 .minor = WATCHDOG_MINOR,
311 .name = "watchdog",
312 .fops = &wdt_fops,
313 };
314
315 /*
316 * Notifier for system down
317 */
318
319 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
320 void *unused)
321 {
322 if(code==SYS_DOWN || code==SYS_HALT)
323 wdt_turnoff();
324 return NOTIFY_DONE;
325 }
326
327 /*
328 * The WDT needs to learn about soft shutdowns in order to
329 * turn the timebomb registers off.
330 */
331
332 static struct notifier_block wdt_notifier=
333 {
334 .notifier_call = wdt_notify_sys,
335 };
336
337 static void __exit w83877f_wdt_unload(void)
338 {
339 wdt_turnoff();
340
341 /* Deregister */
342 misc_deregister(&wdt_miscdev);
343
344 unregister_reboot_notifier(&wdt_notifier);
345 release_region(WDT_PING,1);
346 release_region(ENABLE_W83877F_PORT,2);
347 }
348
349 static int __init w83877f_wdt_init(void)
350 {
351 int rc = -EBUSY;
352
353 if(timeout < 1 || timeout > 3600) /* arbitrary upper limit */
354 {
355 timeout = WATCHDOG_TIMEOUT;
356 printk(KERN_INFO PFX "timeout value must be 1<=x<=3600, using %d\n",
357 timeout);
358 }
359
360 if (!request_region(ENABLE_W83877F_PORT, 2, "W83877F WDT"))
361 {
362 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
363 ENABLE_W83877F_PORT);
364 rc = -EIO;
365 goto err_out;
366 }
367
368 if (!request_region(WDT_PING, 1, "W8387FF WDT"))
369 {
370 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
371 WDT_PING);
372 rc = -EIO;
373 goto err_out_region1;
374 }
375
376 rc = register_reboot_notifier(&wdt_notifier);
377 if (rc)
378 {
379 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
380 rc);
381 goto err_out_region2;
382 }
383
384 rc = misc_register(&wdt_miscdev);
385 if (rc)
386 {
387 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
388 wdt_miscdev.minor, rc);
389 goto err_out_reboot;
390 }
391
392 printk(KERN_INFO PFX "WDT driver for W83877F initialised. timeout=%d sec (nowayout=%d)\n",
393 timeout, nowayout);
394
395 return 0;
396
397 err_out_reboot:
398 unregister_reboot_notifier(&wdt_notifier);
399 err_out_region2:
400 release_region(WDT_PING,1);
401 err_out_region1:
402 release_region(ENABLE_W83877F_PORT,2);
403 err_out:
404 return rc;
405 }
406
407 module_init(w83877f_wdt_init);
408 module_exit(w83877f_wdt_unload);
409
410 MODULE_AUTHOR("Scott and Bill Jennings");
411 MODULE_DESCRIPTION("Driver for watchdog timer in w83877f chip");
412 MODULE_LICENSE("GPL");
413 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
414
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