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
28 * added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS,
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
34 * made timeout (the emulated heartbeat) a
36 * made the keepalive ping an internal subroutine
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.
45 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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>
55 #include <linux/ioport.h>
56 #include <linux/notifier.h>
57 #include <linux/reboot.h>
58 #include <linux/init.h>
60 #include <linux/uaccess.h>
61 #include <asm/system.h>
63 #define OUR_NAME "w83877f_wdt"
65 #define ENABLE_W83877F_PORT 0x3F0
66 #define ENABLE_W83877F 0x87
67 #define DISABLE_W83877F 0xAA
68 #define WDT_PING 0x443
69 #define WDT_REGISTER 0x14
70 #define WDT_ENABLE 0x9C
71 #define WDT_DISABLE 0x8C
74 * The W83877F seems to be fixed at 1.6s timeout (at least on the
75 * EMACS PC-104 board I'm using). If we reset the watchdog every
76 * ~250ms we should be safe. */
78 #define WDT_INTERVAL (HZ/4+1)
81 * We must not require too good response from the userspace daemon.
82 * Here we require the userspace daemon to send us a heartbeat
83 * char to /dev/watchdog every 30 seconds.
86 #define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */
87 /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
88 static int timeout = WATCHDOG_TIMEOUT;
89 module_param(timeout, int, 0);
90 MODULE_PARM_DESC(timeout,
91 "Watchdog timeout in seconds. (1<=timeout<=3600, default="
92 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
95 static bool nowayout = WATCHDOG_NOWAYOUT;
96 module_param(nowayout, bool, 0);
97 MODULE_PARM_DESC(nowayout,
98 "Watchdog cannot be stopped once started (default="
99 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
101 static void wdt_timer_ping(unsigned long);
102 static DEFINE_TIMER(timer, wdt_timer_ping, 0, 0);
103 static unsigned long next_heartbeat;
104 static unsigned long wdt_is_open;
105 static char wdt_expect_close;
106 static DEFINE_SPINLOCK(wdt_spinlock);
112 static void wdt_timer_ping(unsigned long data)
114 /* If we got a heartbeat pulse within the WDT_US_INTERVAL
115 * we agree to ping the WDT
117 if (time_before(jiffies, next_heartbeat)) {
119 spin_lock(&wdt_spinlock);
121 /* Ping the WDT by reading from WDT_PING */
124 /* Re-set the timer interval */
125 mod_timer(&timer, jiffies + WDT_INTERVAL);
127 spin_unlock(&wdt_spinlock);
130 pr_warn("Heartbeat lost! Will not ping the watchdog\n");
137 static void wdt_change(int writeval)
140 spin_lock_irqsave(&wdt_spinlock, flags);
145 /* make W83877F available */
146 outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT);
147 outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT);
149 /* enable watchdog */
150 outb_p(WDT_REGISTER, ENABLE_W83877F_PORT);
151 outb_p(writeval, ENABLE_W83877F_PORT+1);
153 /* lock the W8387FF away */
154 outb_p(DISABLE_W83877F, ENABLE_W83877F_PORT);
156 spin_unlock_irqrestore(&wdt_spinlock, flags);
159 static void wdt_startup(void)
161 next_heartbeat = jiffies + (timeout * HZ);
163 /* Start the timer */
164 mod_timer(&timer, jiffies + WDT_INTERVAL);
166 wdt_change(WDT_ENABLE);
168 pr_info("Watchdog timer is now enabled\n");
171 static void wdt_turnoff(void)
176 wdt_change(WDT_DISABLE);
178 pr_info("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,
192 size_t count, loff_t *ppos)
194 /* See if we got the magic character 'V' and reload the timer */
199 /* note: just in case someone wrote the magic
200 character five months ago... */
201 wdt_expect_close = 0;
203 /* scan to see whether or not we got the
205 for (ofs = 0; ofs != count; ofs++) {
207 if (get_user(c, buf + ofs))
210 wdt_expect_close = 42;
214 /* someone wrote to us, we should restart timer */
220 static int fop_open(struct inode *inode, struct file *file)
222 /* Just in case we're already talking to someone... */
223 if (test_and_set_bit(0, &wdt_is_open))
226 /* Good, fire up the show */
228 return nonseekable_open(inode, file);
231 static int fop_close(struct inode *inode, struct file *file)
233 if (wdt_expect_close == 42)
237 pr_crit("device file closed unexpectedly. Will not stop the WDT!\n");
239 clear_bit(0, &wdt_is_open);
240 wdt_expect_close = 0;
244 static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
246 void __user *argp = (void __user *)arg;
247 int __user *p = argp;
248 static const struct watchdog_info ident = {
249 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
251 .firmware_version = 1,
252 .identity = "W83877F",
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_SETOPTIONS:
263 int new_options, retval = -EINVAL;
265 if (get_user(new_options, p))
268 if (new_options & WDIOS_DISABLECARD) {
273 if (new_options & WDIOS_ENABLECARD) {
280 case WDIOC_KEEPALIVE:
283 case WDIOC_SETTIMEOUT:
287 if (get_user(new_timeout, p))
290 /* arbitrary upper limit */
291 if (new_timeout < 1 || new_timeout > 3600)
294 timeout = new_timeout;
298 case WDIOC_GETTIMEOUT:
299 return put_user(timeout, p);
305 static const struct file_operations wdt_fops = {
306 .owner = THIS_MODULE,
310 .release = fop_close,
311 .unlocked_ioctl = fop_ioctl,
314 static struct miscdevice wdt_miscdev = {
315 .minor = WATCHDOG_MINOR,
321 * Notifier for system down
324 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
327 if (code == SYS_DOWN || code == SYS_HALT)
333 * The WDT needs to learn about soft shutdowns in order to
334 * turn the timebomb registers off.
337 static struct notifier_block wdt_notifier = {
338 .notifier_call = wdt_notify_sys,
341 static void __exit w83877f_wdt_unload(void)
346 misc_deregister(&wdt_miscdev);
348 unregister_reboot_notifier(&wdt_notifier);
349 release_region(WDT_PING, 1);
350 release_region(ENABLE_W83877F_PORT, 2);
353 static int __init w83877f_wdt_init(void)
357 if (timeout < 1 || timeout > 3600) { /* arbitrary upper limit */
358 timeout = WATCHDOG_TIMEOUT;
359 pr_info("timeout value must be 1 <= x <= 3600, using %d\n",
363 if (!request_region(ENABLE_W83877F_PORT, 2, "W83877F WDT")) {
364 pr_err("I/O address 0x%04x already in use\n",
365 ENABLE_W83877F_PORT);
370 if (!request_region(WDT_PING, 1, "W8387FF WDT")) {
371 pr_err("I/O address 0x%04x already in use\n", WDT_PING);
373 goto err_out_region1;
376 rc = register_reboot_notifier(&wdt_notifier);
378 pr_err("cannot register reboot notifier (err=%d)\n", rc);
379 goto err_out_region2;
382 rc = misc_register(&wdt_miscdev);
384 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
385 wdt_miscdev.minor, rc);
389 pr_info("WDT driver for W83877F initialised. timeout=%d sec (nowayout=%d)\n",
395 unregister_reboot_notifier(&wdt_notifier);
397 release_region(WDT_PING, 1);
399 release_region(ENABLE_W83877F_PORT, 2);
404 module_init(w83877f_wdt_init);
405 module_exit(w83877f_wdt_unload);
407 MODULE_AUTHOR("Scott and Bill Jennings");
408 MODULE_DESCRIPTION("Driver for watchdog timer in w83877f chip");
409 MODULE_LICENSE("GPL");
410 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);