2 * Intel 21285 watchdog driver
3 * Copyright (c) Phil Blundell <pb@nexus.co.uk>, 1998
7 * SoftDog 0.05: A Software Watchdog Device
9 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
10 * All Rights Reserved.
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version
15 * 2 of the License, or (at your option) any later version.
19 #include <linux/module.h>
20 #include <linux/moduleparam.h>
21 #include <linux/types.h>
22 #include <linux/kernel.h>
25 #include <linux/miscdevice.h>
26 #include <linux/watchdog.h>
27 #include <linux/reboot.h>
28 #include <linux/init.h>
29 #include <linux/interrupt.h>
30 #include <linux/uaccess.h>
31 #include <linux/irq.h>
32 #include <mach/hardware.h>
34 #include <asm/mach-types.h>
35 #include <asm/system_info.h>
36 #include <asm/hardware/dec21285.h>
39 * Define this to stop the watchdog actually rebooting the machine.
43 static unsigned int soft_margin = 60; /* in seconds */
44 static unsigned int reload;
45 static unsigned long timer_alive;
49 * If the timer expires..
51 static void watchdog_fire(int irq, void *dev_id)
53 printk(KERN_CRIT "Watchdog: Would Reboot.\n");
62 static void watchdog_ping(void)
64 *CSR_TIMER4_LOAD = reload;
68 * Allow only one person to hold it open
70 static int watchdog_open(struct inode *inode, struct file *file)
74 if (*CSR_SA110_CNTL & (1 << 13))
77 if (test_and_set_bit(1, &timer_alive))
80 reload = soft_margin * (mem_fclk_21285 / 256);
84 *CSR_TIMER4_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD
88 ret = request_irq(IRQ_TIMER4, watchdog_fire, 0, "watchdog", NULL);
91 clear_bit(1, &timer_alive);
95 * Setting this bit is irreversible; once enabled, there is
96 * no way to disable the watchdog.
98 *CSR_SA110_CNTL |= 1 << 13;
102 nonseekable_open(inode, file);
107 * Shut off the timer.
108 * Note: if we really have enabled the watchdog, there
109 * is no way to turn off.
111 static int watchdog_release(struct inode *inode, struct file *file)
114 free_irq(IRQ_TIMER4, NULL);
115 clear_bit(1, &timer_alive);
120 static ssize_t watchdog_write(struct file *file, const char __user *data,
121 size_t len, loff_t *ppos)
132 static const struct watchdog_info ident = {
133 .options = WDIOF_SETTIMEOUT,
134 .identity = "Footbridge Watchdog",
137 static long watchdog_ioctl(struct file *file, unsigned int cmd,
140 unsigned int new_margin;
141 int __user *int_arg = (int __user *)arg;
145 case WDIOC_GETSUPPORT:
147 if (copy_to_user((void __user *)arg, &ident, sizeof(ident)))
151 case WDIOC_GETSTATUS:
152 case WDIOC_GETBOOTSTATUS:
153 ret = put_user(0, int_arg);
156 case WDIOC_KEEPALIVE:
161 case WDIOC_SETTIMEOUT:
162 ret = get_user(new_margin, int_arg);
166 /* Arbitrary, can't find the card's limits */
167 if (new_margin < 0 || new_margin > 60) {
172 soft_margin = new_margin;
173 reload = soft_margin * (mem_fclk_21285 / 256);
176 case WDIOC_GETTIMEOUT:
177 ret = put_user(soft_margin, int_arg);
183 static const struct file_operations watchdog_fops = {
184 .owner = THIS_MODULE,
186 .write = watchdog_write,
187 .unlocked_ioctl = watchdog_ioctl,
188 .open = watchdog_open,
189 .release = watchdog_release,
192 static struct miscdevice watchdog_miscdev = {
193 .minor = WATCHDOG_MINOR,
195 .fops = &watchdog_fops,
198 static int __init footbridge_watchdog_init(void)
202 if (machine_is_netwinder())
205 retval = misc_register(&watchdog_miscdev);
210 "Footbridge Watchdog Timer: 0.01, timer margin: %d sec\n",
213 if (machine_is_cats())
215 "Warning: Watchdog reset may not work on this machine.\n");
219 static void __exit footbridge_watchdog_exit(void)
221 misc_deregister(&watchdog_miscdev);
224 MODULE_AUTHOR("Phil Blundell <pb@nexus.co.uk>");
225 MODULE_DESCRIPTION("Footbridge watchdog driver");
226 MODULE_LICENSE("GPL");
227 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
229 module_param(soft_margin, int, 0);
230 MODULE_PARM_DESC(soft_margin, "Watchdog timeout in seconds");
232 module_init(footbridge_watchdog_init);
233 module_exit(footbridge_watchdog_exit);