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=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
104
105 static void wdt_timer_ping(unsigned long);
106 static DEFINE_TIMER(timer, wdt_timer_ping, 0, 0);
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 mod_timer(&timer, jiffies + WDT_INTERVAL);
126 } else {
127 printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n");
128 }
129 }
130
131 /*
132 * Utility routines
133 */
134
135 static void wdt_startup(void)
136 {
137 next_heartbeat = jiffies + (timeout * HZ);
138
139 /* Start the timer */
140 mod_timer(&timer, jiffies + WDT_INTERVAL);
141 printk(KERN_INFO PFX "Watchdog timer is now enabled.\n");
142 }
143
144 static void wdt_turnoff(void)
145 {
146 /* Stop the timer */
147 del_timer(&timer);
148 inb_p(wdt_stop);
149 printk(KERN_INFO PFX "Watchdog timer is now disabled...\n");
150 }
151
152 static void wdt_keepalive(void)
153 {
154 /* user land ping */
155 next_heartbeat = jiffies + (timeout * HZ);
156 }
157
158 /*
159 * /dev/watchdog handling
160 */
161
162 static ssize_t fop_write(struct file * file, const char __user * buf, size_t count, loff_t * ppos)
163 {
164 /* See if we got the magic character 'V' and reload the timer */
165 if(count)
166 {
167 if (!nowayout)
168 {
169 size_t ofs;
170
171 /* note: just in case someone wrote the magic character
172 * five months ago... */
173 wdt_expect_close = 0;
174
175 /* scan to see whether or not we got the magic character */
176 for(ofs = 0; ofs != count; ofs++)
177 {
178 char c;
179 if(get_user(c, buf+ofs))
180 return -EFAULT;
181 if(c == 'V')
182 wdt_expect_close = 42;
183 }
184 }
185
186 /* Well, anyhow someone wrote to us, we should return that favour */
187 wdt_keepalive();
188 }
189 return count;
190 }
191
192 static int fop_open(struct inode * inode, struct file * file)
193 {
194 /* Just in case we're already talking to someone... */
195 if(test_and_set_bit(0, &wdt_is_open))
196 return -EBUSY;
197
198 if (nowayout)
199 __module_get(THIS_MODULE);
200
201 /* Good, fire up the show */
202 wdt_startup();
203 return nonseekable_open(inode, file);
204 }
205
206 static int fop_close(struct inode * inode, struct file * file)
207 {
208 if(wdt_expect_close == 42)
209 wdt_turnoff();
210 else {
211 del_timer(&timer);
212 printk(KERN_CRIT PFX "device file closed unexpectedly. Will not stop the WDT!\n");
213 }
214 clear_bit(0, &wdt_is_open);
215 wdt_expect_close = 0;
216 return 0;
217 }
218
219 static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
220 unsigned long arg)
221 {
222 void __user *argp = (void __user *)arg;
223 int __user *p = argp;
224 static struct watchdog_info ident=
225 {
226 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
227 .firmware_version = 1,
228 .identity = "SBC60xx",
229 };
230
231 switch(cmd)
232 {
233 default:
234 return -ENOTTY;
235 case WDIOC_GETSUPPORT:
236 return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0;
237 case WDIOC_GETSTATUS:
238 case WDIOC_GETBOOTSTATUS:
239 return put_user(0, p);
240 case WDIOC_KEEPALIVE:
241 wdt_keepalive();
242 return 0;
243 case WDIOC_SETOPTIONS:
244 {
245 int new_options, retval = -EINVAL;
246
247 if(get_user(new_options, p))
248 return -EFAULT;
249
250 if(new_options & WDIOS_DISABLECARD) {
251 wdt_turnoff();
252 retval = 0;
253 }
254
255 if(new_options & WDIOS_ENABLECARD) {
256 wdt_startup();
257 retval = 0;
258 }
259
260 return retval;
261 }
262 case WDIOC_SETTIMEOUT:
263 {
264 int new_timeout;
265
266 if(get_user(new_timeout, p))
267 return -EFAULT;
268
269 if(new_timeout < 1 || new_timeout > 3600) /* arbitrary upper limit */
270 return -EINVAL;
271
272 timeout = new_timeout;
273 wdt_keepalive();
274 /* Fall through */
275 }
276 case WDIOC_GETTIMEOUT:
277 return put_user(timeout, p);
278 }
279 }
280
281 static const struct file_operations wdt_fops = {
282 .owner = THIS_MODULE,
283 .llseek = no_llseek,
284 .write = fop_write,
285 .open = fop_open,
286 .release = fop_close,
287 .ioctl = fop_ioctl,
288 };
289
290 static struct miscdevice wdt_miscdev = {
291 .minor = WATCHDOG_MINOR,
292 .name = "watchdog",
293 .fops = &wdt_fops,
294 };
295
296 /*
297 * Notifier for system down
298 */
299
300 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
301 void *unused)
302 {
303 if(code==SYS_DOWN || code==SYS_HALT)
304 wdt_turnoff();
305 return NOTIFY_DONE;
306 }
307
308 /*
309 * The WDT needs to learn about soft shutdowns in order to
310 * turn the timebomb registers off.
311 */
312
313 static struct notifier_block wdt_notifier=
314 {
315 .notifier_call = wdt_notify_sys,
316 };
317
318 static void __exit sbc60xxwdt_unload(void)
319 {
320 wdt_turnoff();
321
322 /* Deregister */
323 misc_deregister(&wdt_miscdev);
324
325 unregister_reboot_notifier(&wdt_notifier);
326 if ((wdt_stop != 0x45) && (wdt_stop != wdt_start))
327 release_region(wdt_stop,1);
328 release_region(wdt_start,1);
329 }
330
331 static int __init sbc60xxwdt_init(void)
332 {
333 int rc = -EBUSY;
334
335 if(timeout < 1 || timeout > 3600) /* arbitrary upper limit */
336 {
337 timeout = WATCHDOG_TIMEOUT;
338 printk(KERN_INFO PFX "timeout value must be 1<=x<=3600, using %d\n",
339 timeout);
340 }
341
342 if (!request_region(wdt_start, 1, "SBC 60XX WDT"))
343 {
344 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
345 wdt_start);
346 rc = -EIO;
347 goto err_out;
348 }
349
350 /* We cannot reserve 0x45 - the kernel already has! */
351 if ((wdt_stop != 0x45) && (wdt_stop != wdt_start))
352 {
353 if (!request_region(wdt_stop, 1, "SBC 60XX WDT"))
354 {
355 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
356 wdt_stop);
357 rc = -EIO;
358 goto err_out_region1;
359 }
360 }
361
362 rc = register_reboot_notifier(&wdt_notifier);
363 if (rc)
364 {
365 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
366 rc);
367 goto err_out_region2;
368 }
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_reboot;
376 }
377
378 printk(KERN_INFO PFX "WDT driver for 60XX single board computer initialised. timeout=%d sec (nowayout=%d)\n",
379 timeout, nowayout);
380
381 return 0;
382
383 err_out_reboot:
384 unregister_reboot_notifier(&wdt_notifier);
385 err_out_region2:
386 if ((wdt_stop != 0x45) && (wdt_stop != wdt_start))
387 release_region(wdt_stop,1);
388 err_out_region1:
389 release_region(wdt_start,1);
390 err_out:
391 return rc;
392 }
393
394 module_init(sbc60xxwdt_init);
395 module_exit(sbc60xxwdt_unload);
396
397 MODULE_AUTHOR("Jakob Oestergaard <jakob@unthought.net>");
398 MODULE_DESCRIPTION("60xx Single Board Computer Watchdog Timer driver");
399 MODULE_LICENSE("GPL");
400 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
401
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