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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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 */
83static int timeout = WATCHDOG_TIMEOUT; /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
84module_param(timeout, int, 0);
85MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
86
87
Andrey Panin4bfdf372005-07-27 11:43:58 -070088static int nowayout = WATCHDOG_NOWAYOUT;
Linus Torvalds1da177e2005-04-16 15:20:36 -070089module_param(nowayout, int, 0);
90MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
91
92static void wdt_timer_ping(unsigned long);
93static struct timer_list timer;
94static unsigned long next_heartbeat;
95static unsigned long wdt_is_open;
96static char wdt_expect_close;
97static spinlock_t wdt_spinlock;
98
99/*
100 * Whack the dog
101 */
102
103static 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
131static 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
153static 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
166static 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
176static void wdt_keepalive(void)
177{
178 /* user land ping */
179 next_heartbeat = jiffies + (timeout * HZ);
180}
181
182/*
183 * /dev/watchdog handling
184 */
185
186static 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
216static 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
227static 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
240static 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
302static 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
311static 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
321static 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
334static struct notifier_block wdt_notifier=
335{
336 .notifier_call = wdt_notify_sys,
337};
338
339static 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
351static 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
405err_out_miscdev:
406 misc_deregister(&wdt_miscdev);
407err_out_region2:
408 release_region(WDT_PING,1);
409err_out_region1:
410 release_region(ENABLE_W83877F_PORT,2);
411err_out:
412 return rc;
413}
414
415module_init(w83877f_wdt_init);
416module_exit(w83877f_wdt_unload);
417
418MODULE_AUTHOR("Scott and Bill Jennings");
419MODULE_DESCRIPTION("Driver for watchdog timer in w83877f chip");
420MODULE_LICENSE("GPL");
421MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);