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1da177e4 LT |
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 | ||
4bfdf378 | 88 | static int nowayout = WATCHDOG_NOWAYOUT; |
1da177e4 LT |
89 | module_param(nowayout, int, 0); |
90 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)"); | |
91 | ||
92 | static void wdt_timer_ping(unsigned long); | |
93 | static struct timer_list timer; | |
94 | static unsigned long next_heartbeat; | |
95 | static unsigned long wdt_is_open; | |
96 | static char wdt_expect_close; | |
97 | static spinlock_t 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 | timer.expires = jiffies + WDT_INTERVAL; | |
118 | add_timer(&timer); | |
119 | ||
120 | spin_unlock(&wdt_spinlock); | |
121 | ||
122 | } else { | |
123 | printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n"); | |
124 | } | |
125 | } | |
126 | ||
127 | /* | |
128 | * Utility routines | |
129 | */ | |
130 | ||
131 | static void wdt_change(int writeval) | |
132 | { | |
133 | unsigned long flags; | |
134 | spin_lock_irqsave(&wdt_spinlock, flags); | |
135 | ||
136 | /* buy some time */ | |
137 | inb_p(WDT_PING); | |
138 | ||
139 | /* make W83877F available */ | |
140 | outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT); | |
141 | outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT); | |
142 | ||
143 | /* enable watchdog */ | |
144 | outb_p(WDT_REGISTER, ENABLE_W83877F_PORT); | |
145 | outb_p(writeval, ENABLE_W83877F_PORT+1); | |
146 | ||
147 | /* lock the W8387FF away */ | |
148 | outb_p(DISABLE_W83877F, ENABLE_W83877F_PORT); | |
149 | ||
150 | spin_unlock_irqrestore(&wdt_spinlock, flags); | |
151 | } | |
152 | ||
153 | static void wdt_startup(void) | |
154 | { | |
155 | next_heartbeat = jiffies + (timeout * HZ); | |
156 | ||
157 | /* Start the timer */ | |
158 | timer.expires = jiffies + WDT_INTERVAL; | |
159 | add_timer(&timer); | |
160 | ||
161 | wdt_change(WDT_ENABLE); | |
162 | ||
163 | printk(KERN_INFO PFX "Watchdog timer is now enabled.\n"); | |
164 | } | |
165 | ||
166 | static void wdt_turnoff(void) | |
167 | { | |
168 | /* Stop the timer */ | |
169 | del_timer(&timer); | |
170 | ||
171 | wdt_change(WDT_DISABLE); | |
172 | ||
173 | printk(KERN_INFO PFX "Watchdog timer is now disabled...\n"); | |
174 | } | |
175 | ||
176 | static void wdt_keepalive(void) | |
177 | { | |
178 | /* user land ping */ | |
179 | next_heartbeat = jiffies + (timeout * HZ); | |
180 | } | |
181 | ||
182 | /* | |
183 | * /dev/watchdog handling | |
184 | */ | |
185 | ||
186 | static ssize_t fop_write(struct file * file, const char __user * buf, size_t count, loff_t * ppos) | |
187 | { | |
188 | /* See if we got the magic character 'V' and reload the timer */ | |
189 | if(count) | |
190 | { | |
191 | if (!nowayout) | |
192 | { | |
193 | size_t ofs; | |
194 | ||
195 | /* note: just in case someone wrote the magic character | |
196 | * five months ago... */ | |
197 | wdt_expect_close = 0; | |
198 | ||
199 | /* scan to see whether or not we got the magic character */ | |
200 | for(ofs = 0; ofs != count; ofs++) | |
201 | { | |
202 | char c; | |
203 | if (get_user(c, buf + ofs)) | |
204 | return -EFAULT; | |
205 | if (c == 'V') | |
206 | wdt_expect_close = 42; | |
207 | } | |
208 | } | |
209 | ||
210 | /* someone wrote to us, we should restart timer */ | |
211 | wdt_keepalive(); | |
212 | } | |
213 | return count; | |
214 | } | |
215 | ||
216 | static int fop_open(struct inode * inode, struct file * file) | |
217 | { | |
218 | /* Just in case we're already talking to someone... */ | |
219 | if(test_and_set_bit(0, &wdt_is_open)) | |
220 | return -EBUSY; | |
221 | ||
222 | /* Good, fire up the show */ | |
223 | wdt_startup(); | |
224 | return nonseekable_open(inode, file); | |
225 | } | |
226 | ||
227 | static int fop_close(struct inode * inode, struct file * file) | |
228 | { | |
229 | if(wdt_expect_close == 42) | |
230 | wdt_turnoff(); | |
231 | else { | |
232 | del_timer(&timer); | |
233 | printk(KERN_CRIT PFX "device file closed unexpectedly. Will not stop the WDT!\n"); | |
234 | } | |
235 | clear_bit(0, &wdt_is_open); | |
236 | wdt_expect_close = 0; | |
237 | return 0; | |
238 | } | |
239 | ||
240 | static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd, | |
241 | unsigned long arg) | |
242 | { | |
243 | void __user *argp = (void __user *)arg; | |
244 | int __user *p = argp; | |
245 | static struct watchdog_info ident= | |
246 | { | |
247 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, | |
248 | .firmware_version = 1, | |
249 | .identity = "W83877F", | |
250 | }; | |
251 | ||
252 | switch(cmd) | |
253 | { | |
254 | default: | |
255 | return -ENOIOCTLCMD; | |
256 | case WDIOC_GETSUPPORT: | |
257 | return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0; | |
258 | case WDIOC_GETSTATUS: | |
259 | case WDIOC_GETBOOTSTATUS: | |
260 | return put_user(0, p); | |
261 | case WDIOC_KEEPALIVE: | |
262 | wdt_keepalive(); | |
263 | return 0; | |
264 | case WDIOC_SETOPTIONS: | |
265 | { | |
266 | int new_options, retval = -EINVAL; | |
267 | ||
268 | if(get_user(new_options, p)) | |
269 | return -EFAULT; | |
270 | ||
271 | if(new_options & WDIOS_DISABLECARD) { | |
272 | wdt_turnoff(); | |
273 | retval = 0; | |
274 | } | |
275 | ||
276 | if(new_options & WDIOS_ENABLECARD) { | |
277 | wdt_startup(); | |
278 | retval = 0; | |
279 | } | |
280 | ||
281 | return retval; | |
282 | } | |
283 | case WDIOC_SETTIMEOUT: | |
284 | { | |
285 | int new_timeout; | |
286 | ||
287 | if(get_user(new_timeout, p)) | |
288 | return -EFAULT; | |
289 | ||
290 | if(new_timeout < 1 || new_timeout > 3600) /* arbitrary upper limit */ | |
291 | return -EINVAL; | |
292 | ||
293 | timeout = new_timeout; | |
294 | wdt_keepalive(); | |
295 | /* Fall through */ | |
296 | } | |
297 | case WDIOC_GETTIMEOUT: | |
298 | return put_user(timeout, p); | |
299 | } | |
300 | } | |
301 | ||
302 | static struct file_operations wdt_fops = { | |
303 | .owner = THIS_MODULE, | |
304 | .llseek = no_llseek, | |
305 | .write = fop_write, | |
306 | .open = fop_open, | |
307 | .release = fop_close, | |
308 | .ioctl = fop_ioctl, | |
309 | }; | |
310 | ||
311 | static struct miscdevice wdt_miscdev = { | |
312 | .minor = WATCHDOG_MINOR, | |
313 | .name = "watchdog", | |
314 | .fops = &wdt_fops, | |
315 | }; | |
316 | ||
317 | /* | |
318 | * Notifier for system down | |
319 | */ | |
320 | ||
321 | static int wdt_notify_sys(struct notifier_block *this, unsigned long code, | |
322 | void *unused) | |
323 | { | |
324 | if(code==SYS_DOWN || code==SYS_HALT) | |
325 | wdt_turnoff(); | |
326 | return NOTIFY_DONE; | |
327 | } | |
328 | ||
329 | /* | |
330 | * The WDT needs to learn about soft shutdowns in order to | |
331 | * turn the timebomb registers off. | |
332 | */ | |
333 | ||
334 | static struct notifier_block wdt_notifier= | |
335 | { | |
336 | .notifier_call = wdt_notify_sys, | |
337 | }; | |
338 | ||
339 | static void __exit w83877f_wdt_unload(void) | |
340 | { | |
341 | wdt_turnoff(); | |
342 | ||
343 | /* Deregister */ | |
344 | misc_deregister(&wdt_miscdev); | |
345 | ||
346 | unregister_reboot_notifier(&wdt_notifier); | |
347 | release_region(WDT_PING,1); | |
348 | release_region(ENABLE_W83877F_PORT,2); | |
349 | } | |
350 | ||
351 | static int __init w83877f_wdt_init(void) | |
352 | { | |
353 | int rc = -EBUSY; | |
354 | ||
355 | spin_lock_init(&wdt_spinlock); | |
356 | ||
357 | if(timeout < 1 || timeout > 3600) /* arbitrary upper limit */ | |
358 | { | |
359 | timeout = WATCHDOG_TIMEOUT; | |
360 | printk(KERN_INFO PFX "timeout value must be 1<=x<=3600, using %d\n", | |
361 | timeout); | |
362 | } | |
363 | ||
364 | if (!request_region(ENABLE_W83877F_PORT, 2, "W83877F WDT")) | |
365 | { | |
366 | printk(KERN_ERR PFX "I/O address 0x%04x already in use\n", | |
367 | ENABLE_W83877F_PORT); | |
368 | rc = -EIO; | |
369 | goto err_out; | |
370 | } | |
371 | ||
372 | if (!request_region(WDT_PING, 1, "W8387FF WDT")) | |
373 | { | |
374 | printk(KERN_ERR PFX "I/O address 0x%04x already in use\n", | |
375 | WDT_PING); | |
376 | rc = -EIO; | |
377 | goto err_out_region1; | |
378 | } | |
379 | ||
380 | init_timer(&timer); | |
381 | timer.function = wdt_timer_ping; | |
382 | timer.data = 0; | |
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_region2; | |
390 | } | |
391 | ||
392 | rc = register_reboot_notifier(&wdt_notifier); | |
393 | if (rc) | |
394 | { | |
395 | printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", | |
396 | rc); | |
397 | goto err_out_miscdev; | |
398 | } | |
399 | ||
400 | printk(KERN_INFO PFX "WDT driver for W83877F initialised. timeout=%d sec (nowayout=%d)\n", | |
401 | timeout, nowayout); | |
402 | ||
403 | return 0; | |
404 | ||
405 | err_out_miscdev: | |
406 | misc_deregister(&wdt_miscdev); | |
407 | err_out_region2: | |
408 | release_region(WDT_PING,1); | |
409 | err_out_region1: | |
410 | release_region(ENABLE_W83877F_PORT,2); | |
411 | err_out: | |
412 | return rc; | |
413 | } | |
414 | ||
415 | module_init(w83877f_wdt_init); | |
416 | module_exit(w83877f_wdt_unload); | |
417 | ||
418 | MODULE_AUTHOR("Scott and Bill Jennings"); | |
419 | MODULE_DESCRIPTION("Driver for watchdog timer in w83877f chip"); | |
420 | MODULE_LICENSE("GPL"); | |
421 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |