1 /*
2 * 60xx Single Board Computer Watchdog Timer driver for Linux 2.2.x
3 *
4 * Based on acquirewdt.c by Alan Cox.
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 *
11 * The author does NOT admit liability nor provide warranty for
12 * any of this software. This material is provided "AS-IS" in
13 * the hope that it may be useful for others.
14 *
15 * (c) Copyright 2000 Jakob Oestergaard <jakob@unthought.net>
16 *
17 * 12/4 - 2000 [Initial revision]
18 * 25/4 - 2000 Added /dev/watchdog support
19 * 09/5 - 2001 [smj@oro.net] fixed fop_write to "return 1" on success
20 * 12/4 - 2002 [rob@osinvestor.com] eliminate fop_read
21 * fix possible wdt_is_open race
22 * add CONFIG_WATCHDOG_NOWAYOUT support
23 * remove lock_kernel/unlock_kernel pairs
24 * added KERN_* to printk's
25 * got rid of extraneous comments
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 * use module_param
31 * made timeout (the emulated heartbeat) a module_param
32 * made the keepalive ping an internal subroutine
33 * made wdt_stop and wdt_start module params
34 * added extra printk's for startup problems
35 * added MODULE_AUTHOR and MODULE_DESCRIPTION info
36 *
37 *
38 * This WDT driver is different from the other Linux WDT
39 * drivers in the following ways:
40 * *) The driver will ping the watchdog by itself, because this
41 * particular WDT has a very short timeout (one second) and it
42 * would be insane to count on any userspace daemon always
43 * getting scheduled within that time frame.
44 *
45 */
46
47 #include <linux/module.h>
48 #include <linux/moduleparam.h>
49 #include <linux/types.h>
50 #include <linux/timer.h>
51 #include <linux/jiffies.h>
52 #include <linux/miscdevice.h>
53 #include <linux/watchdog.h>
54 #include <linux/fs.h>
55 #include <linux/ioport.h>
56 #include <linux/notifier.h>
57 #include <linux/reboot.h>
58 #include <linux/init.h>
59
60 #include <asm/io.h>
61 #include <asm/uaccess.h>
62 #include <asm/system.h>
63
64 #define OUR_NAME "sbc60xxwdt"
65 #define PFX OUR_NAME ": "
66
67 /*
68 * You must set these - The driver cannot probe for the settings
69 */
70
71 static int wdt_stop = 0x45;
72 module_param(wdt_stop, int, 0);
73 MODULE_PARM_DESC(wdt_stop, "SBC60xx WDT 'stop' io port (default 0x45)");
74
75 static int wdt_start = 0x443;
76 module_param(wdt_start, int, 0);
77 MODULE_PARM_DESC(wdt_start, "SBC60xx WDT 'start' io port (default 0x443)");
78
79 /*
80 * The 60xx board can use watchdog timeout values from one second
81 * to several minutes. The default is one second, so if we reset
82 * the watchdog every ~250ms we should be safe.
83 */
84
85 #define WDT_INTERVAL (HZ/4+1)
86
87 /*
88 * We must not require too good response from the userspace daemon.
89 * Here we require the userspace daemon to send us a heartbeat
90 * char to /dev/watchdog every 30 seconds.
91 * If the daemon pulses us every 25 seconds, we can still afford
92 * a 5 second scheduling delay on the (high priority) daemon. That
93 * should be sufficient for a box under any load.
94 */
95
96 #define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */
97 static int timeout = WATCHDOG_TIMEOUT; /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
98 module_param(timeout, int, 0);
99 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
100
101 static int nowayout = WATCHDOG_NOWAYOUT;
102 module_param(nowayout, int, 0);
103 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
104
105 static void wdt_timer_ping(unsigned long);
106 static struct timer_list timer;
107 static unsigned long next_heartbeat;
108 static unsigned long wdt_is_open;
109 static char wdt_expect_close;
110
111 /*
112 * Whack the dog
113 */
114
115 static void wdt_timer_ping(unsigned long data)
116 {
117 /* If we got a heartbeat pulse within the WDT_US_INTERVAL
118 * we agree to ping the WDT
119 */
120 if(time_before(jiffies, next_heartbeat))
121 {
122 /* Ping the WDT by reading from wdt_start */
123 inb_p(wdt_start);
124 /* Re-set the timer interval */
125 timer.expires = jiffies + WDT_INTERVAL;
126 add_timer(&timer);
127 } else {
128 printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n");
129 }
130 }
131
132 /*
133 * Utility routines
134 */
135
136 static void wdt_startup(void)
137 {
138 next_heartbeat = jiffies + (timeout * HZ);
139
140 /* Start the timer */
141 timer.expires = jiffies + WDT_INTERVAL;
142 add_timer(&timer);
143 printk(KERN_INFO PFX "Watchdog timer is now enabled.\n");
144 }
145
146 static void wdt_turnoff(void)
147 {
148 /* Stop the timer */
149 del_timer(&timer);
150 inb_p(wdt_stop);
151 printk(KERN_INFO PFX "Watchdog timer is now disabled...\n");
152 }
153
154 static void wdt_keepalive(void)
155 {
156 /* user land ping */
157 next_heartbeat = jiffies + (timeout * HZ);
158 }
159
160 /*
161 * /dev/watchdog handling
162 */
163
164 static ssize_t fop_write(struct file * file, const char __user * buf, size_t count, loff_t * ppos)
165 {
166 /* See if we got the magic character 'V' and reload the timer */
167 if(count)
168 {
169 if (!nowayout)
170 {
171 size_t ofs;
172
173 /* note: just in case someone wrote the magic character
174 * five months ago... */
175 wdt_expect_close = 0;
176
177 /* scan to see whether or not we got the magic character */
178 for(ofs = 0; ofs != count; ofs++)
179 {
180 char c;
181 if(get_user(c, buf+ofs))
182 return -EFAULT;
183 if(c == 'V')
184 wdt_expect_close = 42;
185 }
186 }
187
188 /* Well, anyhow someone wrote to us, we should return that favour */
189 wdt_keepalive();
190 }
191 return count;
192 }
193
194 static int fop_open(struct inode * inode, struct file * file)
195 {
196 nonseekable_open(inode, file);
197
198 /* Just in case we're already talking to someone... */
199 if(test_and_set_bit(0, &wdt_is_open))
200 return -EBUSY;
201
202 if (nowayout)
203 __module_get(THIS_MODULE);
204
205 /* Good, fire up the show */
206 wdt_startup();
207 return 0;
208 }
209
210 static int fop_close(struct inode * inode, struct file * file)
211 {
212 if(wdt_expect_close == 42)
213 wdt_turnoff();
214 else {
215 del_timer(&timer);
216 printk(KERN_CRIT PFX "device file closed unexpectedly. Will not stop the WDT!\n");
217 }
218 clear_bit(0, &wdt_is_open);
219 wdt_expect_close = 0;
220 return 0;
221 }
222
223 static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
224 unsigned long arg)
225 {
226 void __user *argp = (void __user *)arg;
227 int __user *p = argp;
228 static struct watchdog_info ident=
229 {
230 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
231 .firmware_version = 1,
232 .identity = "SBC60xx",
233 };
234
235 switch(cmd)
236 {
237 default:
238 return -ENOIOCTLCMD;
239 case WDIOC_GETSUPPORT:
240 return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0;
241 case WDIOC_GETSTATUS:
242 case WDIOC_GETBOOTSTATUS:
243 return put_user(0, p);
244 case WDIOC_KEEPALIVE:
245 wdt_keepalive();
246 return 0;
247 case WDIOC_SETOPTIONS:
248 {
249 int new_options, retval = -EINVAL;
250
251 if(get_user(new_options, p))
252 return -EFAULT;
253
254 if(new_options & WDIOS_DISABLECARD) {
255 wdt_turnoff();
256 retval = 0;
257 }
258
259 if(new_options & WDIOS_ENABLECARD) {
260 wdt_startup();
261 retval = 0;
262 }
263
264 return retval;
265 }
266 case WDIOC_SETTIMEOUT:
267 {
268 int new_timeout;
269
270 if(get_user(new_timeout, p))
271 return -EFAULT;
272
273 if(new_timeout < 1 || new_timeout > 3600) /* arbitrary upper limit */
274 return -EINVAL;
275
276 timeout = new_timeout;
277 wdt_keepalive();
278 /* Fall through */
279 }
280 case WDIOC_GETTIMEOUT:
281 return put_user(timeout, p);
282 }
283 }
284
285 static struct file_operations wdt_fops = {
286 .owner = THIS_MODULE,
287 .llseek = no_llseek,
288 .write = fop_write,
289 .open = fop_open,
290 .release = fop_close,
291 .ioctl = fop_ioctl,
292 };
293
294 static struct miscdevice wdt_miscdev = {
295 .minor = WATCHDOG_MINOR,
296 .name = "watchdog",
297 .fops = &wdt_fops,
298 };
299
300 /*
301 * Notifier for system down
302 */
303
304 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
305 void *unused)
306 {
307 if(code==SYS_DOWN || code==SYS_HALT)
308 wdt_turnoff();
309 return NOTIFY_DONE;
310 }
311
312 /*
313 * The WDT needs to learn about soft shutdowns in order to
314 * turn the timebomb registers off.
315 */
316
317 static struct notifier_block wdt_notifier=
318 {
319 .notifier_call = wdt_notify_sys,
320 };
321
322 static void __exit sbc60xxwdt_unload(void)
323 {
324 wdt_turnoff();
325
326 /* Deregister */
327 misc_deregister(&wdt_miscdev);
328
329 unregister_reboot_notifier(&wdt_notifier);
330 if ((wdt_stop != 0x45) && (wdt_stop != wdt_start))
331 release_region(wdt_stop,1);
332 release_region(wdt_start,1);
333 }
334
335 static int __init sbc60xxwdt_init(void)
336 {
337 int rc = -EBUSY;
338
339 if(timeout < 1 || timeout > 3600) /* arbitrary upper limit */
340 {
341 timeout = WATCHDOG_TIMEOUT;
342 printk(KERN_INFO PFX "timeout value must be 1<=x<=3600, using %d\n",
343 timeout);
344 }
345
346 if (!request_region(wdt_start, 1, "SBC 60XX WDT"))
347 {
348 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
349 wdt_start);
350 rc = -EIO;
351 goto err_out;
352 }
353
354 /* We cannot reserve 0x45 - the kernel already has! */
355 if ((wdt_stop != 0x45) && (wdt_stop != wdt_start))
356 {
357 if (!request_region(wdt_stop, 1, "SBC 60XX WDT"))
358 {
359 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
360 wdt_stop);
361 rc = -EIO;
362 goto err_out_region1;
363 }
364 }
365
366 init_timer(&timer);
367 timer.function = wdt_timer_ping;
368 timer.data = 0;
369
370 rc = misc_register(&wdt_miscdev);
371 if (rc)
372 {
373 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
374 wdt_miscdev.minor, rc);
375 goto err_out_region2;
376 }
377
378 rc = register_reboot_notifier(&wdt_notifier);
379 if (rc)
380 {
381 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
382 rc);
383 goto err_out_miscdev;
384 }
385
386 printk(KERN_INFO PFX "WDT driver for 60XX single board computer initialised. timeout=%d sec (nowayout=%d)\n",
387 timeout, nowayout);
388
389 return 0;
390
391 err_out_miscdev:
392 misc_deregister(&wdt_miscdev);
393 err_out_region2:
394 if ((wdt_stop != 0x45) && (wdt_stop != wdt_start))
395 release_region(wdt_stop,1);
396 err_out_region1:
397 release_region(wdt_start,1);
398 err_out:
399 return rc;
400 }
401
402 module_init(sbc60xxwdt_init);
403 module_exit(sbc60xxwdt_unload);
404
405 MODULE_AUTHOR("Jakob Oestergaard <jakob@unthought.net>");
406 MODULE_DESCRIPTION("60xx Single Board Computer Watchdog Timer driver");
407 MODULE_LICENSE("GPL");
408 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
409
This page was automatically generated by the
LXR engine.
Visit the LXR main site for more
information.