2 * IB700 Single Board Computer WDT driver
4 * (c) Copyright 2001 Charles Howes <chowes@vsol.net>
6 * Based on advantechwdt.c which is based on acquirewdt.c which
9 * (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
11 * Based on acquirewdt.c which is based on wdt.c.
12 * Original copyright messages:
14 * (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
15 * http://www.redhat.com
17 * This program is free software; you can redistribute it and/or
18 * modify it under the terms of the GNU General Public License
19 * as published by the Free Software Foundation; either version
20 * 2 of the License, or (at your option) any later version.
22 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
23 * warranty for any of this software. This material is provided
24 * "AS-IS" and at no charge.
26 * (c) Copyright 1995 Alan Cox <alan@redhat.com>
28 * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
29 * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
30 * Added timeout module option to override default
34 #include <linux/config.h>
35 #include <linux/module.h>
36 #include <linux/types.h>
37 #include <linux/miscdevice.h>
38 #include <linux/watchdog.h>
39 #include <linux/ioport.h>
40 #include <linux/notifier.h>
42 #include <linux/reboot.h>
43 #include <linux/init.h>
44 #include <linux/spinlock.h>
45 #include <linux/moduleparam.h>
48 #include <asm/uaccess.h>
49 #include <asm/system.h>
51 static unsigned long ibwdt_is_open;
52 static spinlock_t ibwdt_lock;
53 static char expect_close;
55 #define PFX "ib700wdt: "
59 * Watchdog Timer Configuration
61 * The function of the watchdog timer is to reset the system
62 * automatically and is defined at I/O port 0443H. To enable the
63 * watchdog timer and allow the system to reset, write I/O port 0443H.
64 * To disable the timer, write I/O port 0441H for the system to stop the
65 * watchdog function. The timer has a tolerance of 20% for its
68 * The following describes how the timer should be programmed.
71 * MOV AX,000FH (Choose the values from 0 to F)
76 * MOV AX,000FH (Any value is fine.)
80 * Watchdog timer control table:
81 * Level Value Time/sec | Level Value Time/sec
93 static int wd_times[] = {
112 #define WDT_STOP 0x441
113 #define WDT_START 0x443
115 /* Default timeout */
116 #define WD_TIMO 0 /* 30 seconds +/- 20%, from table */
118 static int wd_margin = WD_TIMO;
120 #ifdef CONFIG_WATCHDOG_NOWAYOUT
121 static int nowayout = 1;
123 static int nowayout = 0;
126 module_param(nowayout, int, 0);
127 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
137 /* Write a watchdog value */
138 outb_p(wd_margin, WDT_START);
142 ibwdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
144 /* Can't seek (pwrite) on this device */
145 if (ppos != &file->f_pos)
152 /* In case it was set long ago */
155 for (i = 0; i != count; i++) {
157 if (get_user(c, buf + i))
169 ibwdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
173 void __user *argp = (void __user *)arg;
174 int __user *p = argp;
176 static struct watchdog_info ident = {
177 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
178 .firmware_version = 1,
179 .identity = "IB700 WDT",
183 case WDIOC_GETSUPPORT:
184 if (copy_to_user(argp, &ident, sizeof(ident)))
188 case WDIOC_GETSTATUS:
189 return put_user(0, p);
191 case WDIOC_KEEPALIVE:
195 case WDIOC_SETTIMEOUT:
196 if (get_user(new_margin, p))
198 if ((new_margin < 0) || (new_margin > 30))
200 for (i = 0x0F; i > -1; i--)
201 if (wd_times[i] > new_margin)
207 case WDIOC_GETTIMEOUT:
208 return put_user(wd_times[wd_margin], p);
218 ibwdt_open(struct inode *inode, struct file *file)
220 spin_lock(&ibwdt_lock);
221 if (test_and_set_bit(0, &ibwdt_is_open)) {
222 spin_unlock(&ibwdt_lock);
226 __module_get(THIS_MODULE);
230 spin_unlock(&ibwdt_lock);
235 ibwdt_close(struct inode *inode, struct file *file)
237 spin_lock(&ibwdt_lock);
238 if (expect_close == 42)
241 printk(KERN_CRIT PFX "WDT device closed unexpectedly. WDT will not stop!\n");
243 clear_bit(0, &ibwdt_is_open);
245 spin_unlock(&ibwdt_lock);
250 * Notifier for system down
254 ibwdt_notify_sys(struct notifier_block *this, unsigned long code,
257 if (code == SYS_DOWN || code == SYS_HALT) {
258 /* Turn the WDT off */
268 static struct file_operations ibwdt_fops = {
269 .owner = THIS_MODULE,
270 .write = ibwdt_write,
271 .ioctl = ibwdt_ioctl,
273 .release = ibwdt_close,
276 static struct miscdevice ibwdt_miscdev = {
277 .minor = WATCHDOG_MINOR,
283 * The WDT needs to learn about soft shutdowns in order to
284 * turn the timebomb registers off.
287 static struct notifier_block ibwdt_notifier = {
288 .notifier_call = ibwdt_notify_sys,
291 static int __init ibwdt_init(void)
295 printk(KERN_INFO PFX "WDT driver for IB700 single board computer initialising.\n");
297 spin_lock_init(&ibwdt_lock);
298 res = misc_register(&ibwdt_miscdev);
300 printk (KERN_ERR PFX "failed to register misc device\n");
304 #if WDT_START != WDT_STOP
305 if (!request_region(WDT_STOP, 1, "IB700 WDT")) {
306 printk (KERN_ERR PFX "STOP method I/O %X is not available.\n", WDT_STOP);
312 if (!request_region(WDT_START, 1, "IB700 WDT")) {
313 printk (KERN_ERR PFX "START method I/O %X is not available.\n", WDT_START);
317 res = register_reboot_notifier(&ibwdt_notifier);
319 printk (KERN_ERR PFX "Failed to register reboot notifier.\n");
325 release_region(WDT_START, 1);
327 #if WDT_START != WDT_STOP
328 release_region(WDT_STOP, 1);
331 misc_deregister(&ibwdt_miscdev);
339 misc_deregister(&ibwdt_miscdev);
340 unregister_reboot_notifier(&ibwdt_notifier);
341 #if WDT_START != WDT_STOP
342 release_region(WDT_STOP,1);
344 release_region(WDT_START,1);
347 module_init(ibwdt_init);
348 module_exit(ibwdt_exit);
350 MODULE_AUTHOR("Charles Howes <chowes@vsol.net>");
351 MODULE_DESCRIPTION("IB700 SBC watchdog driver");
352 MODULE_LICENSE("GPL");
353 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
355 /* end of ib700wdt.c */