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1da177e4 LT |
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 | ||
4bfdf378 | 101 | static int nowayout = WATCHDOG_NOWAYOUT; |
1da177e4 LT |
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); |