2 * W83877F Computer Watchdog Timer driver
4 * Based on acquirewdt.c by Alan Cox,
5 * and sbc60xxwdt.c by Jakob Oestergaard <jakob@unthought.net>
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.
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.
16 * (c) Copyright 2001 Scott Jennings <linuxdrivers@oro.net>
18 * 4/19 - 2001 [Initial revision]
19 * 9/27 - 2001 Added spinlocking
20 * 4/12 - 2002 [rob@osinvestor.com] Eliminate extra comments
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
32 * made timeout (the emulated heartbeat) a module_param
33 * made the keepalive ping an internal subroutine
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.
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>
50 #include <linux/ioport.h>
51 #include <linux/notifier.h>
52 #include <linux/reboot.h>
53 #include <linux/init.h>
55 #include <asm/uaccess.h>
56 #include <asm/system.h>
58 #define OUR_NAME "w83877f_wdt"
59 #define PFX OUR_NAME ": "
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
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. */
74 #define WDT_INTERVAL (HZ/4+1)
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.
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) ")");
88 #ifdef CONFIG_WATCHDOG_NOWAYOUT
89 static int nowayout = 1;
91 static int nowayout = 0;
94 module_param(nowayout, int, 0);
95 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
97 static void wdt_timer_ping(unsigned long);
98 static struct timer_list timer;
99 static unsigned long next_heartbeat;
100 static unsigned long wdt_is_open;
101 static char wdt_expect_close;
102 static spinlock_t wdt_spinlock;
108 static void wdt_timer_ping(unsigned long data)
110 /* If we got a heartbeat pulse within the WDT_US_INTERVAL
111 * we agree to ping the WDT
113 if(time_before(jiffies, next_heartbeat))
116 spin_lock(&wdt_spinlock);
118 /* Ping the WDT by reading from WDT_PING */
121 /* Re-set the timer interval */
122 timer.expires = jiffies + WDT_INTERVAL;
125 spin_unlock(&wdt_spinlock);
128 printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n");
136 static void wdt_change(int writeval)
139 spin_lock_irqsave(&wdt_spinlock, flags);
144 /* make W83877F available */
145 outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT);
146 outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT);
148 /* enable watchdog */
149 outb_p(WDT_REGISTER, ENABLE_W83877F_PORT);
150 outb_p(writeval, ENABLE_W83877F_PORT+1);
152 /* lock the W8387FF away */
153 outb_p(DISABLE_W83877F, ENABLE_W83877F_PORT);
155 spin_unlock_irqrestore(&wdt_spinlock, flags);
158 static void wdt_startup(void)
160 next_heartbeat = jiffies + (timeout * HZ);
162 /* Start the timer */
163 timer.expires = jiffies + WDT_INTERVAL;
166 wdt_change(WDT_ENABLE);
168 printk(KERN_INFO PFX "Watchdog timer is now enabled.\n");
171 static void wdt_turnoff(void)
176 wdt_change(WDT_DISABLE);
178 printk(KERN_INFO PFX "Watchdog timer is now disabled...\n");
181 static void wdt_keepalive(void)
184 next_heartbeat = jiffies + (timeout * HZ);
188 * /dev/watchdog handling
191 static ssize_t fop_write(struct file * file, const char __user * buf, size_t count, loff_t * ppos)
193 /* See if we got the magic character 'V' and reload the timer */
200 /* note: just in case someone wrote the magic character
201 * five months ago... */
202 wdt_expect_close = 0;
204 /* scan to see whether or not we got the magic character */
205 for(ofs = 0; ofs != count; ofs++)
208 if (get_user(c, buf + ofs))
211 wdt_expect_close = 42;
215 /* someone wrote to us, we should restart timer */
221 static int fop_open(struct inode * inode, struct file * file)
223 /* Just in case we're already talking to someone... */
224 if(test_and_set_bit(0, &wdt_is_open))
227 /* Good, fire up the show */
229 return nonseekable_open(inode, file);
232 static int fop_close(struct inode * inode, struct file * file)
234 if(wdt_expect_close == 42)
238 printk(KERN_CRIT PFX "device file closed unexpectedly. Will not stop the WDT!\n");
240 clear_bit(0, &wdt_is_open);
241 wdt_expect_close = 0;
245 static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
248 void __user *argp = (void __user *)arg;
249 int __user *p = argp;
250 static struct watchdog_info ident=
252 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
253 .firmware_version = 1,
254 .identity = "W83877F",
261 case WDIOC_GETSUPPORT:
262 return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0;
263 case WDIOC_GETSTATUS:
264 case WDIOC_GETBOOTSTATUS:
265 return put_user(0, p);
266 case WDIOC_KEEPALIVE:
269 case WDIOC_SETOPTIONS:
271 int new_options, retval = -EINVAL;
273 if(get_user(new_options, p))
276 if(new_options & WDIOS_DISABLECARD) {
281 if(new_options & WDIOS_ENABLECARD) {
288 case WDIOC_SETTIMEOUT:
292 if(get_user(new_timeout, p))
295 if(new_timeout < 1 || new_timeout > 3600) /* arbitrary upper limit */
298 timeout = new_timeout;
302 case WDIOC_GETTIMEOUT:
303 return put_user(timeout, p);
307 static struct file_operations wdt_fops = {
308 .owner = THIS_MODULE,
312 .release = fop_close,
316 static struct miscdevice wdt_miscdev = {
317 .minor = WATCHDOG_MINOR,
323 * Notifier for system down
326 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
329 if(code==SYS_DOWN || code==SYS_HALT)
335 * The WDT needs to learn about soft shutdowns in order to
336 * turn the timebomb registers off.
339 static struct notifier_block wdt_notifier=
341 .notifier_call = wdt_notify_sys,
344 static void __exit w83877f_wdt_unload(void)
349 misc_deregister(&wdt_miscdev);
351 unregister_reboot_notifier(&wdt_notifier);
352 release_region(WDT_PING,1);
353 release_region(ENABLE_W83877F_PORT,2);
356 static int __init w83877f_wdt_init(void)
360 spin_lock_init(&wdt_spinlock);
362 if(timeout < 1 || timeout > 3600) /* arbitrary upper limit */
364 timeout = WATCHDOG_TIMEOUT;
365 printk(KERN_INFO PFX "timeout value must be 1<=x<=3600, using %d\n",
369 if (!request_region(ENABLE_W83877F_PORT, 2, "W83877F WDT"))
371 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
372 ENABLE_W83877F_PORT);
377 if (!request_region(WDT_PING, 1, "W8387FF WDT"))
379 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
382 goto err_out_region1;
386 timer.function = wdt_timer_ping;
389 rc = misc_register(&wdt_miscdev);
392 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
393 wdt_miscdev.minor, rc);
394 goto err_out_region2;
397 rc = register_reboot_notifier(&wdt_notifier);
400 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
402 goto err_out_miscdev;
405 printk(KERN_INFO PFX "WDT driver for W83877F initialised. timeout=%d sec (nowayout=%d)\n",
411 misc_deregister(&wdt_miscdev);
413 release_region(WDT_PING,1);
415 release_region(ENABLE_W83877F_PORT,2);
420 module_init(w83877f_wdt_init);
421 module_exit(w83877f_wdt_unload);
423 MODULE_AUTHOR("Scott and Bill Jennings");
424 MODULE_DESCRIPTION("Driver for watchdog timer in w83877f chip");
425 MODULE_LICENSE("GPL");
426 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);