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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 | ||
101 | #ifdef CONFIG_WATCHDOG_NOWAYOUT | |
102 | static int nowayout = 1; | |
103 | #else | |
104 | static int nowayout = 0; | |
105 | #endif | |
106 | ||
107 | module_param(nowayout, int, 0); | |
108 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)"); | |
109 | ||
110 | static void wdt_timer_ping(unsigned long); | |
111 | static struct timer_list timer; | |
112 | static unsigned long next_heartbeat; | |
113 | static unsigned long wdt_is_open; | |
114 | static char wdt_expect_close; | |
115 | ||
116 | /* | |
117 | * Whack the dog | |
118 | */ | |
119 | ||
120 | static void wdt_timer_ping(unsigned long data) | |
121 | { | |
122 | /* If we got a heartbeat pulse within the WDT_US_INTERVAL | |
123 | * we agree to ping the WDT | |
124 | */ | |
125 | if(time_before(jiffies, next_heartbeat)) | |
126 | { | |
127 | /* Ping the WDT by reading from wdt_start */ | |
128 | inb_p(wdt_start); | |
129 | /* Re-set the timer interval */ | |
130 | timer.expires = jiffies + WDT_INTERVAL; | |
131 | add_timer(&timer); | |
132 | } else { | |
133 | printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n"); | |
134 | } | |
135 | } | |
136 | ||
137 | /* | |
138 | * Utility routines | |
139 | */ | |
140 | ||
141 | static void wdt_startup(void) | |
142 | { | |
143 | next_heartbeat = jiffies + (timeout * HZ); | |
144 | ||
145 | /* Start the timer */ | |
146 | timer.expires = jiffies + WDT_INTERVAL; | |
147 | add_timer(&timer); | |
148 | printk(KERN_INFO PFX "Watchdog timer is now enabled.\n"); | |
149 | } | |
150 | ||
151 | static void wdt_turnoff(void) | |
152 | { | |
153 | /* Stop the timer */ | |
154 | del_timer(&timer); | |
155 | inb_p(wdt_stop); | |
156 | printk(KERN_INFO PFX "Watchdog timer is now disabled...\n"); | |
157 | } | |
158 | ||
159 | static void wdt_keepalive(void) | |
160 | { | |
161 | /* user land ping */ | |
162 | next_heartbeat = jiffies + (timeout * HZ); | |
163 | } | |
164 | ||
165 | /* | |
166 | * /dev/watchdog handling | |
167 | */ | |
168 | ||
169 | static ssize_t fop_write(struct file * file, const char __user * buf, size_t count, loff_t * ppos) | |
170 | { | |
171 | /* See if we got the magic character 'V' and reload the timer */ | |
172 | if(count) | |
173 | { | |
174 | if (!nowayout) | |
175 | { | |
176 | size_t ofs; | |
177 | ||
178 | /* note: just in case someone wrote the magic character | |
179 | * five months ago... */ | |
180 | wdt_expect_close = 0; | |
181 | ||
182 | /* scan to see whether or not we got the magic character */ | |
183 | for(ofs = 0; ofs != count; ofs++) | |
184 | { | |
185 | char c; | |
186 | if(get_user(c, buf+ofs)) | |
187 | return -EFAULT; | |
188 | if(c == 'V') | |
189 | wdt_expect_close = 42; | |
190 | } | |
191 | } | |
192 | ||
193 | /* Well, anyhow someone wrote to us, we should return that favour */ | |
194 | wdt_keepalive(); | |
195 | } | |
196 | return count; | |
197 | } | |
198 | ||
199 | static int fop_open(struct inode * inode, struct file * file) | |
200 | { | |
201 | nonseekable_open(inode, file); | |
202 | ||
203 | /* Just in case we're already talking to someone... */ | |
204 | if(test_and_set_bit(0, &wdt_is_open)) | |
205 | return -EBUSY; | |
206 | ||
207 | if (nowayout) | |
208 | __module_get(THIS_MODULE); | |
209 | ||
210 | /* Good, fire up the show */ | |
211 | wdt_startup(); | |
212 | return 0; | |
213 | } | |
214 | ||
215 | static int fop_close(struct inode * inode, struct file * file) | |
216 | { | |
217 | if(wdt_expect_close == 42) | |
218 | wdt_turnoff(); | |
219 | else { | |
220 | del_timer(&timer); | |
221 | printk(KERN_CRIT PFX "device file closed unexpectedly. Will not stop the WDT!\n"); | |
222 | } | |
223 | clear_bit(0, &wdt_is_open); | |
224 | wdt_expect_close = 0; | |
225 | return 0; | |
226 | } | |
227 | ||
228 | static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd, | |
229 | unsigned long arg) | |
230 | { | |
231 | void __user *argp = (void __user *)arg; | |
232 | int __user *p = argp; | |
233 | static struct watchdog_info ident= | |
234 | { | |
235 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, | |
236 | .firmware_version = 1, | |
237 | .identity = "SBC60xx", | |
238 | }; | |
239 | ||
240 | switch(cmd) | |
241 | { | |
242 | default: | |
243 | return -ENOIOCTLCMD; | |
244 | case WDIOC_GETSUPPORT: | |
245 | return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0; | |
246 | case WDIOC_GETSTATUS: | |
247 | case WDIOC_GETBOOTSTATUS: | |
248 | return put_user(0, p); | |
249 | case WDIOC_KEEPALIVE: | |
250 | wdt_keepalive(); | |
251 | return 0; | |
252 | case WDIOC_SETOPTIONS: | |
253 | { | |
254 | int new_options, retval = -EINVAL; | |
255 | ||
256 | if(get_user(new_options, p)) | |
257 | return -EFAULT; | |
258 | ||
259 | if(new_options & WDIOS_DISABLECARD) { | |
260 | wdt_turnoff(); | |
261 | retval = 0; | |
262 | } | |
263 | ||
264 | if(new_options & WDIOS_ENABLECARD) { | |
265 | wdt_startup(); | |
266 | retval = 0; | |
267 | } | |
268 | ||
269 | return retval; | |
270 | } | |
271 | case WDIOC_SETTIMEOUT: | |
272 | { | |
273 | int new_timeout; | |
274 | ||
275 | if(get_user(new_timeout, p)) | |
276 | return -EFAULT; | |
277 | ||
278 | if(new_timeout < 1 || new_timeout > 3600) /* arbitrary upper limit */ | |
279 | return -EINVAL; | |
280 | ||
281 | timeout = new_timeout; | |
282 | wdt_keepalive(); | |
283 | /* Fall through */ | |
284 | } | |
285 | case WDIOC_GETTIMEOUT: | |
286 | return put_user(timeout, p); | |
287 | } | |
288 | } | |
289 | ||
290 | static struct file_operations wdt_fops = { | |
291 | .owner = THIS_MODULE, | |
292 | .llseek = no_llseek, | |
293 | .write = fop_write, | |
294 | .open = fop_open, | |
295 | .release = fop_close, | |
296 | .ioctl = fop_ioctl, | |
297 | }; | |
298 | ||
299 | static struct miscdevice wdt_miscdev = { | |
300 | .minor = WATCHDOG_MINOR, | |
301 | .name = "watchdog", | |
302 | .fops = &wdt_fops, | |
303 | }; | |
304 | ||
305 | /* | |
306 | * Notifier for system down | |
307 | */ | |
308 | ||
309 | static int wdt_notify_sys(struct notifier_block *this, unsigned long code, | |
310 | void *unused) | |
311 | { | |
312 | if(code==SYS_DOWN || code==SYS_HALT) | |
313 | wdt_turnoff(); | |
314 | return NOTIFY_DONE; | |
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 | { | |
324 | .notifier_call = wdt_notify_sys, | |
325 | }; | |
326 | ||
327 | static void __exit sbc60xxwdt_unload(void) | |
328 | { | |
329 | wdt_turnoff(); | |
330 | ||
331 | /* Deregister */ | |
332 | misc_deregister(&wdt_miscdev); | |
333 | ||
334 | unregister_reboot_notifier(&wdt_notifier); | |
335 | if ((wdt_stop != 0x45) && (wdt_stop != wdt_start)) | |
336 | release_region(wdt_stop,1); | |
337 | release_region(wdt_start,1); | |
338 | } | |
339 | ||
340 | static int __init sbc60xxwdt_init(void) | |
341 | { | |
342 | int rc = -EBUSY; | |
343 | ||
344 | if(timeout < 1 || timeout > 3600) /* arbitrary upper limit */ | |
345 | { | |
346 | timeout = WATCHDOG_TIMEOUT; | |
347 | printk(KERN_INFO PFX "timeout value must be 1<=x<=3600, using %d\n", | |
348 | timeout); | |
349 | } | |
350 | ||
351 | if (!request_region(wdt_start, 1, "SBC 60XX WDT")) | |
352 | { | |
353 | printk(KERN_ERR PFX "I/O address 0x%04x already in use\n", | |
354 | wdt_start); | |
355 | rc = -EIO; | |
356 | goto err_out; | |
357 | } | |
358 | ||
359 | /* We cannot reserve 0x45 - the kernel already has! */ | |
360 | if ((wdt_stop != 0x45) && (wdt_stop != wdt_start)) | |
361 | { | |
362 | if (!request_region(wdt_stop, 1, "SBC 60XX WDT")) | |
363 | { | |
364 | printk(KERN_ERR PFX "I/O address 0x%04x already in use\n", | |
365 | wdt_stop); | |
366 | rc = -EIO; | |
367 | goto err_out_region1; | |
368 | } | |
369 | } | |
370 | ||
371 | init_timer(&timer); | |
372 | timer.function = wdt_timer_ping; | |
373 | timer.data = 0; | |
374 | ||
375 | rc = misc_register(&wdt_miscdev); | |
376 | if (rc) | |
377 | { | |
378 | printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", | |
379 | wdt_miscdev.minor, rc); | |
380 | goto err_out_region2; | |
381 | } | |
382 | ||
383 | rc = register_reboot_notifier(&wdt_notifier); | |
384 | if (rc) | |
385 | { | |
386 | printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", | |
387 | rc); | |
388 | goto err_out_miscdev; | |
389 | } | |
390 | ||
391 | printk(KERN_INFO PFX "WDT driver for 60XX single board computer initialised. timeout=%d sec (nowayout=%d)\n", | |
392 | timeout, nowayout); | |
393 | ||
394 | return 0; | |
395 | ||
396 | err_out_miscdev: | |
397 | misc_deregister(&wdt_miscdev); | |
398 | err_out_region2: | |
399 | if ((wdt_stop != 0x45) && (wdt_stop != wdt_start)) | |
400 | release_region(wdt_stop,1); | |
401 | err_out_region1: | |
402 | release_region(wdt_start,1); | |
403 | err_out: | |
404 | return rc; | |
405 | } | |
406 | ||
407 | module_init(sbc60xxwdt_init); | |
408 | module_exit(sbc60xxwdt_unload); | |
409 | ||
410 | MODULE_AUTHOR("Jakob Oestergaard <jakob@unthought.net>"); | |
411 | MODULE_DESCRIPTION("60xx Single Board Computer Watchdog Timer driver"); | |
412 | MODULE_LICENSE("GPL"); | |
413 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |