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/module.h>
35 #include <linux/types.h>
36 #include <linux/miscdevice.h>
37 #include <linux/watchdog.h>
38 #include <linux/ioport.h>
39 #include <linux/notifier.h>
41 #include <linux/reboot.h>
42 #include <linux/init.h>
43 #include <linux/spinlock.h>
44 #include <linux/moduleparam.h>
47 #include <asm/uaccess.h>
48 #include <asm/system.h>
50 static unsigned long ibwdt_is_open;
51 static spinlock_t ibwdt_lock;
52 static char expect_close;
54 #define PFX "ib700wdt: "
58 * Watchdog Timer Configuration
60 * The function of the watchdog timer is to reset the system
61 * automatically and is defined at I/O port 0443H. To enable the
62 * watchdog timer and allow the system to reset, write I/O port 0443H.
63 * To disable the timer, write I/O port 0441H for the system to stop the
64 * watchdog function. The timer has a tolerance of 20% for its
67 * The following describes how the timer should be programmed.
70 * MOV AX,000FH (Choose the values from 0 to F)
75 * MOV AX,000FH (Any value is fine.)
79 * Watchdog timer control table:
80 * Level Value Time/sec | Level Value Time/sec
92 static int wd_times[] = {
111 #define WDT_STOP 0x441
112 #define WDT_START 0x443
114 /* Default timeout */
115 #define WD_TIMO 0 /* 30 seconds +/- 20%, from table */
117 static int wd_margin = WD_TIMO;
119 static int nowayout = WATCHDOG_NOWAYOUT;
120 module_param(nowayout, int, 0);
121 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
125 * Watchdog Operations
131 /* Write a watchdog value */
132 outb_p(wd_margin, WDT_START);
142 ibwdt_set_heartbeat(int t)
146 if ((t < 0) || (t > 30))
149 for (i = 0x0F; i > -1; i--)
157 * /dev/watchdog handling
161 ibwdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
167 /* In case it was set long ago */
170 for (i = 0; i != count; i++) {
172 if (get_user(c, buf + i))
184 ibwdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
188 void __user *argp = (void __user *)arg;
189 int __user *p = argp;
191 static struct watchdog_info ident = {
192 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
193 .firmware_version = 1,
194 .identity = "IB700 WDT",
198 case WDIOC_GETSUPPORT:
199 if (copy_to_user(argp, &ident, sizeof(ident)))
203 case WDIOC_GETSTATUS:
204 case WDIOC_GETBOOTSTATUS:
205 return put_user(0, p);
207 case WDIOC_KEEPALIVE:
211 case WDIOC_SETTIMEOUT:
212 if (get_user(new_margin, p))
214 if (ibwdt_set_heartbeat(new_margin))
219 case WDIOC_GETTIMEOUT:
220 return put_user(wd_times[wd_margin], p);
230 ibwdt_open(struct inode *inode, struct file *file)
232 spin_lock(&ibwdt_lock);
233 if (test_and_set_bit(0, &ibwdt_is_open)) {
234 spin_unlock(&ibwdt_lock);
238 __module_get(THIS_MODULE);
242 spin_unlock(&ibwdt_lock);
243 return nonseekable_open(inode, file);
247 ibwdt_close(struct inode *inode, struct file *file)
249 spin_lock(&ibwdt_lock);
250 if (expect_close == 42) {
253 printk(KERN_CRIT PFX "WDT device closed unexpectedly. WDT will not stop!\n");
256 clear_bit(0, &ibwdt_is_open);
258 spin_unlock(&ibwdt_lock);
263 * Notifier for system down
267 ibwdt_notify_sys(struct notifier_block *this, unsigned long code,
270 if (code == SYS_DOWN || code == SYS_HALT) {
271 /* Turn the WDT off */
281 static const struct file_operations ibwdt_fops = {
282 .owner = THIS_MODULE,
284 .write = ibwdt_write,
285 .ioctl = ibwdt_ioctl,
287 .release = ibwdt_close,
290 static struct miscdevice ibwdt_miscdev = {
291 .minor = WATCHDOG_MINOR,
297 * The WDT needs to learn about soft shutdowns in order to
298 * turn the timebomb registers off.
301 static struct notifier_block ibwdt_notifier = {
302 .notifier_call = ibwdt_notify_sys,
306 * Init & exit routines
309 static int __init ibwdt_init(void)
313 printk(KERN_INFO PFX "WDT driver for IB700 single board computer initialising.\n");
315 spin_lock_init(&ibwdt_lock);
317 #if WDT_START != WDT_STOP
318 if (!request_region(WDT_STOP, 1, "IB700 WDT")) {
319 printk (KERN_ERR PFX "STOP method I/O %X is not available.\n", WDT_STOP);
325 if (!request_region(WDT_START, 1, "IB700 WDT")) {
326 printk (KERN_ERR PFX "START method I/O %X is not available.\n", WDT_START);
331 res = register_reboot_notifier(&ibwdt_notifier);
333 printk (KERN_ERR PFX "Failed to register reboot notifier.\n");
337 res = misc_register(&ibwdt_miscdev);
339 printk (KERN_ERR PFX "failed to register misc device\n");
345 unregister_reboot_notifier(&ibwdt_notifier);
347 release_region(WDT_START, 1);
349 #if WDT_START != WDT_STOP
350 release_region(WDT_STOP, 1);
359 misc_deregister(&ibwdt_miscdev);
360 unregister_reboot_notifier(&ibwdt_notifier);
361 release_region(WDT_START,1);
362 #if WDT_START != WDT_STOP
363 release_region(WDT_STOP,1);
367 module_init(ibwdt_init);
368 module_exit(ibwdt_exit);
370 MODULE_AUTHOR("Charles Howes <chowes@vsol.net>");
371 MODULE_DESCRIPTION("IB700 SBC watchdog driver");
372 MODULE_LICENSE("GPL");
373 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
375 /* end of ib700wdt.c */