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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 |
27 | * the driver offers |
28 | * added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS, |
29 | * WDIOC_SETTIMEOUT, |
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 |
34 | * made timeout (the emulated heartbeat) a |
35 | * module_param |
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 | |
45 | #include <linux/module.h> |
46 | #include <linux/moduleparam.h> |
47 | #include <linux/types.h> |
48 | #include <linux/timer.h> |
49 | #include <linux/jiffies.h> |
50 | #include <linux/miscdevice.h> |
51 | #include <linux/watchdog.h> |
52 | #include <linux/fs.h> |
53 | #include <linux/ioport.h> |
54 | #include <linux/notifier.h> |
55 | #include <linux/reboot.h> |
56 | #include <linux/init.h> |
57 | #include <linux/io.h> |
58 | #include <linux/uaccess.h> |
59 | #include <asm/system.h> |
60 | |
61 | #define OUR_NAME "w83877f_wdt" |
62 | #define PFX OUR_NAME ": " |
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 */ |
86 | /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */ |
87 | static int timeout = WATCHDOG_TIMEOUT; |
88 | module_param(timeout, int, 0); |
89 | MODULE_PARM_DESC(timeout, |
90 | "Watchdog timeout in seconds. (1<=timeout<=3600, default=" |
91 | __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); |
92 | |
93 | |
94 | static int nowayout = WATCHDOG_NOWAYOUT; |
95 | module_param(nowayout, int, 0); |
96 | MODULE_PARM_DESC(nowayout, |
97 | "Watchdog cannot be stopped once started (default=" |
98 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
99 | |
100 | static void wdt_timer_ping(unsigned long); |
101 | static DEFINE_TIMER(timer, wdt_timer_ping, 0, 0); |
102 | static unsigned long next_heartbeat; |
103 | static unsigned long wdt_is_open; |
104 | static char wdt_expect_close; |
105 | static DEFINE_SPINLOCK(wdt_spinlock); |
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 | */ |
116 | if (time_before(jiffies, next_heartbeat)) { |
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 */ |
124 | mod_timer(&timer, jiffies + WDT_INTERVAL); |
125 | |
126 | spin_unlock(&wdt_spinlock); |
127 | |
128 | } else |
129 | printk(KERN_WARNING PFX |
130 | "Heartbeat lost! Will not ping the watchdog\n"); |
131 | } |
132 | |
133 | /* |
134 | * Utility routines |
135 | */ |
136 | |
137 | static void wdt_change(int writeval) |
138 | { |
139 | unsigned long flags; |
140 | spin_lock_irqsave(&wdt_spinlock, flags); |
141 | |
142 | /* buy some time */ |
143 | inb_p(WDT_PING); |
144 | |
145 | /* make W83877F available */ |
146 | outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT); |
147 | outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT); |
148 | |
149 | /* enable watchdog */ |
150 | outb_p(WDT_REGISTER, ENABLE_W83877F_PORT); |
151 | outb_p(writeval, ENABLE_W83877F_PORT+1); |
152 | |
153 | /* lock the W8387FF away */ |
154 | outb_p(DISABLE_W83877F, ENABLE_W83877F_PORT); |
155 | |
156 | spin_unlock_irqrestore(&wdt_spinlock, flags); |
157 | } |
158 | |
159 | static void wdt_startup(void) |
160 | { |
161 | next_heartbeat = jiffies + (timeout * HZ); |
162 | |
163 | /* Start the timer */ |
164 | mod_timer(&timer, jiffies + WDT_INTERVAL); |
165 | |
166 | wdt_change(WDT_ENABLE); |
167 | |
168 | printk(KERN_INFO PFX "Watchdog timer is now enabled.\n"); |
169 | } |
170 | |
171 | static void wdt_turnoff(void) |
172 | { |
173 | /* Stop the timer */ |
174 | del_timer(&timer); |
175 | |
176 | wdt_change(WDT_DISABLE); |
177 | |
178 | printk(KERN_INFO PFX "Watchdog timer is now disabled...\n"); |
179 | } |
180 | |
181 | static void wdt_keepalive(void) |
182 | { |
183 | /* user land ping */ |
184 | next_heartbeat = jiffies + (timeout * HZ); |
185 | } |
186 | |
187 | /* |
188 | * /dev/watchdog handling |
189 | */ |
190 | |
191 | static ssize_t fop_write(struct file *file, const char __user *buf, |
192 | size_t count, loff_t *ppos) |
193 | { |
194 | /* See if we got the magic character 'V' and reload the timer */ |
195 | if (count) { |
196 | if (!nowayout) { |
197 | size_t ofs; |
198 | |
199 | /* note: just in case someone wrote the magic |
200 | character five months ago... */ |
201 | wdt_expect_close = 0; |
202 | |
203 | /* scan to see whether or not we got the |
204 | magic character */ |
205 | for (ofs = 0; ofs != count; ofs++) { |
206 | char c; |
207 | if (get_user(c, buf + ofs)) |
208 | return -EFAULT; |
209 | if (c == 'V') |
210 | wdt_expect_close = 42; |
211 | } |
212 | } |
213 | |
214 | /* someone wrote to us, we should restart timer */ |
215 | wdt_keepalive(); |
216 | } |
217 | return count; |
218 | } |
219 | |
220 | static int fop_open(struct inode *inode, struct file *file) |
221 | { |
222 | /* Just in case we're already talking to someone... */ |
223 | if (test_and_set_bit(0, &wdt_is_open)) |
224 | return -EBUSY; |
225 | |
226 | /* Good, fire up the show */ |
227 | wdt_startup(); |
228 | return nonseekable_open(inode, file); |
229 | } |
230 | |
231 | static int fop_close(struct inode *inode, struct file *file) |
232 | { |
233 | if (wdt_expect_close == 42) |
234 | wdt_turnoff(); |
235 | else { |
236 | del_timer(&timer); |
237 | printk(KERN_CRIT PFX |
238 | "device file closed unexpectedly. Will not stop the WDT!\n"); |
239 | } |
240 | clear_bit(0, &wdt_is_open); |
241 | wdt_expect_close = 0; |
242 | return 0; |
243 | } |
244 | |
245 | static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
246 | { |
247 | void __user *argp = (void __user *)arg; |
248 | int __user *p = argp; |
249 | static const struct watchdog_info ident = { |
250 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
251 | | WDIOF_MAGICCLOSE, |
252 | .firmware_version = 1, |
253 | .identity = "W83877F", |
254 | }; |
255 | |
256 | switch (cmd) { |
257 | case WDIOC_GETSUPPORT: |
258 | return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; |
259 | case WDIOC_GETSTATUS: |
260 | case WDIOC_GETBOOTSTATUS: |
261 | return put_user(0, p); |
262 | case WDIOC_SETOPTIONS: |
263 | { |
264 | int new_options, retval = -EINVAL; |
265 | |
266 | if (get_user(new_options, p)) |
267 | return -EFAULT; |
268 | |
269 | if (new_options & WDIOS_DISABLECARD) { |
270 | wdt_turnoff(); |
271 | retval = 0; |
272 | } |
273 | |
274 | if (new_options & WDIOS_ENABLECARD) { |
275 | wdt_startup(); |
276 | retval = 0; |
277 | } |
278 | |
279 | return retval; |
280 | } |
281 | case WDIOC_KEEPALIVE: |
282 | wdt_keepalive(); |
283 | return 0; |
284 | case WDIOC_SETTIMEOUT: |
285 | { |
286 | int new_timeout; |
287 | |
288 | if (get_user(new_timeout, p)) |
289 | return -EFAULT; |
290 | |
291 | /* arbitrary upper limit */ |
292 | if (new_timeout < 1 || new_timeout > 3600) |
293 | return -EINVAL; |
294 | |
295 | timeout = new_timeout; |
296 | wdt_keepalive(); |
297 | /* Fall through */ |
298 | } |
299 | case WDIOC_GETTIMEOUT: |
300 | return put_user(timeout, p); |
301 | default: |
302 | return -ENOTTY; |
303 | } |
304 | } |
305 | |
306 | static const struct file_operations wdt_fops = { |
307 | .owner = THIS_MODULE, |
308 | .llseek = no_llseek, |
309 | .write = fop_write, |
310 | .open = fop_open, |
311 | .release = fop_close, |
312 | .unlocked_ioctl = fop_ioctl, |
313 | }; |
314 | |
315 | static struct miscdevice wdt_miscdev = { |
316 | .minor = WATCHDOG_MINOR, |
317 | .name = "watchdog", |
318 | .fops = &wdt_fops, |
319 | }; |
320 | |
321 | /* |
322 | * Notifier for system down |
323 | */ |
324 | |
325 | static int wdt_notify_sys(struct notifier_block *this, unsigned long code, |
326 | void *unused) |
327 | { |
328 | if (code == SYS_DOWN || code == SYS_HALT) |
329 | wdt_turnoff(); |
330 | return NOTIFY_DONE; |
331 | } |
332 | |
333 | /* |
334 | * The WDT needs to learn about soft shutdowns in order to |
335 | * turn the timebomb registers off. |
336 | */ |
337 | |
338 | static struct notifier_block wdt_notifier = { |
339 | .notifier_call = wdt_notify_sys, |
340 | }; |
341 | |
342 | static void __exit w83877f_wdt_unload(void) |
343 | { |
344 | wdt_turnoff(); |
345 | |
346 | /* Deregister */ |
347 | misc_deregister(&wdt_miscdev); |
348 | |
349 | unregister_reboot_notifier(&wdt_notifier); |
350 | release_region(WDT_PING, 1); |
351 | release_region(ENABLE_W83877F_PORT, 2); |
352 | } |
353 | |
354 | static int __init w83877f_wdt_init(void) |
355 | { |
356 | int rc = -EBUSY; |
357 | |
358 | if (timeout < 1 || timeout > 3600) { /* arbitrary upper limit */ |
359 | timeout = WATCHDOG_TIMEOUT; |
360 | printk(KERN_INFO PFX |
361 | "timeout value must be 1 <= x <= 3600, using %d\n", |
362 | timeout); |
363 | } |
364 | |
365 | if (!request_region(ENABLE_W83877F_PORT, 2, "W83877F WDT")) { |
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 | printk(KERN_ERR PFX "I/O address 0x%04x already in use\n", |
374 | WDT_PING); |
375 | rc = -EIO; |
376 | goto err_out_region1; |
377 | } |
378 | |
379 | rc = register_reboot_notifier(&wdt_notifier); |
380 | if (rc) { |
381 | printk(KERN_ERR PFX |
382 | "cannot register reboot notifier (err=%d)\n", rc); |
383 | goto err_out_region2; |
384 | } |
385 | |
386 | rc = misc_register(&wdt_miscdev); |
387 | if (rc) { |
388 | printk(KERN_ERR PFX |
389 | "cannot register miscdev on minor=%d (err=%d)\n", |
390 | wdt_miscdev.minor, rc); |
391 | goto err_out_reboot; |
392 | } |
393 | |
394 | printk(KERN_INFO PFX |
395 | "WDT driver for W83877F initialised. timeout=%d sec (nowayout=%d)\n", |
396 | timeout, nowayout); |
397 | |
398 | return 0; |
399 | |
400 | err_out_reboot: |
401 | unregister_reboot_notifier(&wdt_notifier); |
402 | err_out_region2: |
403 | release_region(WDT_PING, 1); |
404 | err_out_region1: |
405 | release_region(ENABLE_W83877F_PORT, 2); |
406 | err_out: |
407 | return rc; |
408 | } |
409 | |
410 | module_init(w83877f_wdt_init); |
411 | module_exit(w83877f_wdt_unload); |
412 | |
413 | MODULE_AUTHOR("Scott and Bill Jennings"); |
414 | MODULE_DESCRIPTION("Driver for watchdog timer in w83877f chip"); |
415 | MODULE_LICENSE("GPL"); |
416 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
417 |
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