diff options
Diffstat (limited to 'drivers/char/watchdog/sbc60xxwdt.c')
-rw-r--r-- | drivers/char/watchdog/sbc60xxwdt.c | 413 |
1 files changed, 413 insertions, 0 deletions
diff --git a/drivers/char/watchdog/sbc60xxwdt.c b/drivers/char/watchdog/sbc60xxwdt.c new file mode 100644 index 000000000000..d7de9880605a --- /dev/null +++ b/drivers/char/watchdog/sbc60xxwdt.c | |||
@@ -0,0 +1,413 @@ | |||
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); | ||