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Commit | Line | Data |
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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 | |
c1cfd1a2 AC |
26 | * changed watchdog_info to correctly reflect what |
27 | * the driver offers | |
28 | * added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS, | |
29 | * WDIOC_SETTIMEOUT, | |
1da177e4 LT |
30 | * WDIOC_GETTIMEOUT, and WDIOC_SETOPTIONS ioctls |
31 | * 09/8 - 2003 [wim@iguana.be] cleanup of trailing spaces | |
32 | * added extra printk's for startup problems | |
33 | * use module_param | |
c1cfd1a2 AC |
34 | * made timeout (the emulated heartbeat) a |
35 | * module_param | |
1da177e4 LT |
36 | * made the keepalive ping an internal subroutine |
37 | * | |
38 | * This WDT driver is different from most other Linux WDT | |
39 | * drivers in that the driver will ping the watchdog by itself, | |
40 | * because this particular WDT has a very short timeout (1.6 | |
41 | * seconds) and it would be insane to count on any userspace | |
42 | * daemon always getting scheduled within that time frame. | |
43 | */ | |
44 | ||
27c766aa JP |
45 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
46 | ||
1da177e4 LT |
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> | |
c1cfd1a2 AC |
59 | #include <linux/io.h> |
60 | #include <linux/uaccess.h> | |
1da177e4 LT |
61 | |
62 | #define OUR_NAME "w83877f_wdt" | |
1da177e4 LT |
63 | |
64 | #define ENABLE_W83877F_PORT 0x3F0 | |
65 | #define ENABLE_W83877F 0x87 | |
66 | #define DISABLE_W83877F 0xAA | |
67 | #define WDT_PING 0x443 | |
68 | #define WDT_REGISTER 0x14 | |
69 | #define WDT_ENABLE 0x9C | |
70 | #define WDT_DISABLE 0x8C | |
71 | ||
72 | /* | |
73 | * The W83877F seems to be fixed at 1.6s timeout (at least on the | |
74 | * EMACS PC-104 board I'm using). If we reset the watchdog every | |
75 | * ~250ms we should be safe. */ | |
76 | ||
77 | #define WDT_INTERVAL (HZ/4+1) | |
78 | ||
79 | /* | |
80 | * We must not require too good response from the userspace daemon. | |
81 | * Here we require the userspace daemon to send us a heartbeat | |
82 | * char to /dev/watchdog every 30 seconds. | |
83 | */ | |
84 | ||
85 | #define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */ | |
c1cfd1a2 AC |
86 | /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */ |
87 | static int timeout = WATCHDOG_TIMEOUT; | |
1da177e4 | 88 | module_param(timeout, int, 0); |
c1cfd1a2 AC |
89 | MODULE_PARM_DESC(timeout, |
90 | "Watchdog timeout in seconds. (1<=timeout<=3600, default=" | |
91 | __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); | |
1da177e4 LT |
92 | |
93 | ||
86a1e189 WVS |
94 | static bool nowayout = WATCHDOG_NOWAYOUT; |
95 | module_param(nowayout, bool, 0); | |
c1cfd1a2 AC |
96 | MODULE_PARM_DESC(nowayout, |
97 | "Watchdog cannot be stopped once started (default=" | |
98 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
1da177e4 LT |
99 | |
100 | static void wdt_timer_ping(unsigned long); | |
82eb7c50 | 101 | static DEFINE_TIMER(timer, wdt_timer_ping, 0, 0); |
1da177e4 LT |
102 | static unsigned long next_heartbeat; |
103 | static unsigned long wdt_is_open; | |
104 | static char wdt_expect_close; | |
c7dfd0cc | 105 | static DEFINE_SPINLOCK(wdt_spinlock); |
1da177e4 LT |
106 | |
107 | /* | |
108 | * Whack the dog | |
109 | */ | |
110 | ||
111 | static void wdt_timer_ping(unsigned long data) | |
112 | { | |
113 | /* If we got a heartbeat pulse within the WDT_US_INTERVAL | |
114 | * we agree to ping the WDT | |
115 | */ | |
c1cfd1a2 | 116 | if (time_before(jiffies, next_heartbeat)) { |
1da177e4 LT |
117 | /* Ping the WDT */ |
118 | spin_lock(&wdt_spinlock); | |
119 | ||
120 | /* Ping the WDT by reading from WDT_PING */ | |
121 | inb_p(WDT_PING); | |
122 | ||
123 | /* Re-set the timer interval */ | |
82eb7c50 | 124 | mod_timer(&timer, jiffies + WDT_INTERVAL); |
1da177e4 LT |
125 | |
126 | spin_unlock(&wdt_spinlock); | |
127 | ||
c1cfd1a2 | 128 | } else |
27c766aa | 129 | pr_warn("Heartbeat lost! Will not ping the watchdog\n"); |
1da177e4 LT |
130 | } |
131 | ||
132 | /* | |
133 | * Utility routines | |
134 | */ | |
135 | ||
136 | static void wdt_change(int writeval) | |
137 | { | |
138 | unsigned long flags; | |
139 | spin_lock_irqsave(&wdt_spinlock, flags); | |
140 | ||
141 | /* buy some time */ | |
142 | inb_p(WDT_PING); | |
143 | ||
144 | /* make W83877F available */ | |
145 | outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT); | |
146 | outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT); | |
147 | ||
148 | /* enable watchdog */ | |
149 | outb_p(WDT_REGISTER, ENABLE_W83877F_PORT); | |
150 | outb_p(writeval, ENABLE_W83877F_PORT+1); | |
151 | ||
152 | /* lock the W8387FF away */ | |
153 | outb_p(DISABLE_W83877F, ENABLE_W83877F_PORT); | |
154 | ||
155 | spin_unlock_irqrestore(&wdt_spinlock, flags); | |
156 | } | |
157 | ||
158 | static void wdt_startup(void) | |
159 | { | |
160 | next_heartbeat = jiffies + (timeout * HZ); | |
161 | ||
162 | /* Start the timer */ | |
82eb7c50 | 163 | mod_timer(&timer, jiffies + WDT_INTERVAL); |
1da177e4 LT |
164 | |
165 | wdt_change(WDT_ENABLE); | |
166 | ||
27c766aa | 167 | pr_info("Watchdog timer is now enabled\n"); |
1da177e4 LT |
168 | } |
169 | ||
170 | static void wdt_turnoff(void) | |
171 | { | |
172 | /* Stop the timer */ | |
173 | del_timer(&timer); | |
174 | ||
175 | wdt_change(WDT_DISABLE); | |
176 | ||
27c766aa | 177 | pr_info("Watchdog timer is now disabled...\n"); |
1da177e4 LT |
178 | } |
179 | ||
180 | static void wdt_keepalive(void) | |
181 | { | |
182 | /* user land ping */ | |
183 | next_heartbeat = jiffies + (timeout * HZ); | |
184 | } | |
185 | ||
186 | /* | |
187 | * /dev/watchdog handling | |
188 | */ | |
189 | ||
c1cfd1a2 AC |
190 | static ssize_t fop_write(struct file *file, const char __user *buf, |
191 | size_t count, loff_t *ppos) | |
1da177e4 LT |
192 | { |
193 | /* See if we got the magic character 'V' and reload the timer */ | |
c1cfd1a2 AC |
194 | if (count) { |
195 | if (!nowayout) { | |
1da177e4 LT |
196 | size_t ofs; |
197 | ||
c1cfd1a2 AC |
198 | /* note: just in case someone wrote the magic |
199 | character five months ago... */ | |
1da177e4 LT |
200 | wdt_expect_close = 0; |
201 | ||
c1cfd1a2 AC |
202 | /* scan to see whether or not we got the |
203 | magic character */ | |
204 | for (ofs = 0; ofs != count; ofs++) { | |
1da177e4 LT |
205 | char c; |
206 | if (get_user(c, buf + ofs)) | |
207 | return -EFAULT; | |
208 | if (c == 'V') | |
209 | wdt_expect_close = 42; | |
210 | } | |
211 | } | |
212 | ||
213 | /* someone wrote to us, we should restart timer */ | |
214 | wdt_keepalive(); | |
215 | } | |
216 | return count; | |
217 | } | |
218 | ||
c1cfd1a2 | 219 | static int fop_open(struct inode *inode, struct file *file) |
1da177e4 LT |
220 | { |
221 | /* Just in case we're already talking to someone... */ | |
c1cfd1a2 | 222 | if (test_and_set_bit(0, &wdt_is_open)) |
1da177e4 LT |
223 | return -EBUSY; |
224 | ||
225 | /* Good, fire up the show */ | |
226 | wdt_startup(); | |
227 | return nonseekable_open(inode, file); | |
228 | } | |
229 | ||
c1cfd1a2 | 230 | static int fop_close(struct inode *inode, struct file *file) |
1da177e4 | 231 | { |
c1cfd1a2 | 232 | if (wdt_expect_close == 42) |
1da177e4 LT |
233 | wdt_turnoff(); |
234 | else { | |
235 | del_timer(&timer); | |
27c766aa | 236 | pr_crit("device file closed unexpectedly. Will not stop the WDT!\n"); |
1da177e4 LT |
237 | } |
238 | clear_bit(0, &wdt_is_open); | |
239 | wdt_expect_close = 0; | |
240 | return 0; | |
241 | } | |
242 | ||
c1cfd1a2 | 243 | static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
1da177e4 LT |
244 | { |
245 | void __user *argp = (void __user *)arg; | |
246 | int __user *p = argp; | |
c1cfd1a2 AC |
247 | static const struct watchdog_info ident = { |
248 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | |
249 | | WDIOF_MAGICCLOSE, | |
1da177e4 LT |
250 | .firmware_version = 1, |
251 | .identity = "W83877F", | |
252 | }; | |
253 | ||
c1cfd1a2 | 254 | switch (cmd) { |
c1cfd1a2 AC |
255 | case WDIOC_GETSUPPORT: |
256 | return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; | |
257 | case WDIOC_GETSTATUS: | |
258 | case WDIOC_GETBOOTSTATUS: | |
259 | return put_user(0, p); | |
c1cfd1a2 | 260 | case WDIOC_SETOPTIONS: |
1da177e4 | 261 | { |
c1cfd1a2 | 262 | int new_options, retval = -EINVAL; |
1da177e4 | 263 | |
c1cfd1a2 AC |
264 | if (get_user(new_options, p)) |
265 | return -EFAULT; | |
1da177e4 | 266 | |
c1cfd1a2 AC |
267 | if (new_options & WDIOS_DISABLECARD) { |
268 | wdt_turnoff(); | |
269 | retval = 0; | |
1da177e4 | 270 | } |
1da177e4 | 271 | |
c1cfd1a2 AC |
272 | if (new_options & WDIOS_ENABLECARD) { |
273 | wdt_startup(); | |
274 | retval = 0; | |
275 | } | |
1da177e4 | 276 | |
c1cfd1a2 AC |
277 | return retval; |
278 | } | |
0c06090c WVS |
279 | case WDIOC_KEEPALIVE: |
280 | wdt_keepalive(); | |
281 | return 0; | |
c1cfd1a2 AC |
282 | case WDIOC_SETTIMEOUT: |
283 | { | |
284 | int new_timeout; | |
1da177e4 | 285 | |
c1cfd1a2 AC |
286 | if (get_user(new_timeout, p)) |
287 | return -EFAULT; | |
288 | ||
289 | /* arbitrary upper limit */ | |
290 | if (new_timeout < 1 || new_timeout > 3600) | |
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); | |
0c06090c WVS |
299 | default: |
300 | return -ENOTTY; | |
1da177e4 LT |
301 | } |
302 | } | |
303 | ||
62322d25 | 304 | static const struct file_operations wdt_fops = { |
1da177e4 LT |
305 | .owner = THIS_MODULE, |
306 | .llseek = no_llseek, | |
307 | .write = fop_write, | |
308 | .open = fop_open, | |
309 | .release = fop_close, | |
c1cfd1a2 | 310 | .unlocked_ioctl = fop_ioctl, |
1da177e4 LT |
311 | }; |
312 | ||
313 | static struct miscdevice wdt_miscdev = { | |
314 | .minor = WATCHDOG_MINOR, | |
315 | .name = "watchdog", | |
316 | .fops = &wdt_fops, | |
317 | }; | |
318 | ||
319 | /* | |
320 | * Notifier for system down | |
321 | */ | |
322 | ||
323 | static int wdt_notify_sys(struct notifier_block *this, unsigned long code, | |
324 | void *unused) | |
325 | { | |
c1cfd1a2 | 326 | if (code == SYS_DOWN || code == SYS_HALT) |
1da177e4 LT |
327 | wdt_turnoff(); |
328 | return NOTIFY_DONE; | |
329 | } | |
330 | ||
331 | /* | |
332 | * The WDT needs to learn about soft shutdowns in order to | |
333 | * turn the timebomb registers off. | |
334 | */ | |
335 | ||
c1cfd1a2 | 336 | static struct notifier_block wdt_notifier = { |
1da177e4 LT |
337 | .notifier_call = wdt_notify_sys, |
338 | }; | |
339 | ||
340 | static void __exit w83877f_wdt_unload(void) | |
341 | { | |
342 | wdt_turnoff(); | |
343 | ||
344 | /* Deregister */ | |
345 | misc_deregister(&wdt_miscdev); | |
346 | ||
347 | unregister_reboot_notifier(&wdt_notifier); | |
c1cfd1a2 AC |
348 | release_region(WDT_PING, 1); |
349 | release_region(ENABLE_W83877F_PORT, 2); | |
1da177e4 LT |
350 | } |
351 | ||
352 | static int __init w83877f_wdt_init(void) | |
353 | { | |
354 | int rc = -EBUSY; | |
355 | ||
c1cfd1a2 | 356 | if (timeout < 1 || timeout > 3600) { /* arbitrary upper limit */ |
1da177e4 | 357 | timeout = WATCHDOG_TIMEOUT; |
27c766aa JP |
358 | pr_info("timeout value must be 1 <= x <= 3600, using %d\n", |
359 | timeout); | |
1da177e4 LT |
360 | } |
361 | ||
c1cfd1a2 | 362 | if (!request_region(ENABLE_W83877F_PORT, 2, "W83877F WDT")) { |
27c766aa JP |
363 | pr_err("I/O address 0x%04x already in use\n", |
364 | ENABLE_W83877F_PORT); | |
1da177e4 LT |
365 | rc = -EIO; |
366 | goto err_out; | |
367 | } | |
368 | ||
c1cfd1a2 | 369 | if (!request_region(WDT_PING, 1, "W8387FF WDT")) { |
27c766aa | 370 | pr_err("I/O address 0x%04x already in use\n", WDT_PING); |
1da177e4 LT |
371 | rc = -EIO; |
372 | goto err_out_region1; | |
373 | } | |
374 | ||
c6cb13ae | 375 | rc = register_reboot_notifier(&wdt_notifier); |
c1cfd1a2 | 376 | if (rc) { |
27c766aa | 377 | pr_err("cannot register reboot notifier (err=%d)\n", rc); |
1da177e4 LT |
378 | goto err_out_region2; |
379 | } | |
380 | ||
c6cb13ae | 381 | rc = misc_register(&wdt_miscdev); |
c1cfd1a2 | 382 | if (rc) { |
27c766aa JP |
383 | pr_err("cannot register miscdev on minor=%d (err=%d)\n", |
384 | wdt_miscdev.minor, rc); | |
c6cb13ae | 385 | goto err_out_reboot; |
1da177e4 LT |
386 | } |
387 | ||
27c766aa | 388 | pr_info("WDT driver for W83877F initialised. timeout=%d sec (nowayout=%d)\n", |
1da177e4 LT |
389 | timeout, nowayout); |
390 | ||
391 | return 0; | |
392 | ||
c6cb13ae WVS |
393 | err_out_reboot: |
394 | unregister_reboot_notifier(&wdt_notifier); | |
1da177e4 | 395 | err_out_region2: |
c1cfd1a2 | 396 | release_region(WDT_PING, 1); |
1da177e4 | 397 | err_out_region1: |
c1cfd1a2 | 398 | release_region(ENABLE_W83877F_PORT, 2); |
1da177e4 LT |
399 | err_out: |
400 | return rc; | |
401 | } | |
402 | ||
403 | module_init(w83877f_wdt_init); | |
404 | module_exit(w83877f_wdt_unload); | |
405 | ||
406 | MODULE_AUTHOR("Scott and Bill Jennings"); | |
407 | MODULE_DESCRIPTION("Driver for watchdog timer in w83877f chip"); | |
408 | MODULE_LICENSE("GPL"); | |
409 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |