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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21 #include <linux/module.h>
22 #include <linux/moduleparam.h>
23 #include <linux/types.h>
24 #include <linux/kernel.h>
27 #include <linux/miscdevice.h>
28 #include <linux/watchdog.h>
29 #include <linux/reboot.h>
30 #include <linux/init.h>
31 #include <linux/interrupt.h>
32 #include <linux/uaccess.h>
33 #include <linux/irq.h>
34 #include <mach/hardware.h>
36 #include <asm/mach-types.h>
37 #include <asm/hardware/dec21285.h>
40 * Define this to stop the watchdog actually rebooting the machine.
44 static unsigned int soft_margin = 60; /* in seconds */
45 static unsigned int reload;
46 static unsigned long timer_alive;
50 * If the timer expires..
52 static void watchdog_fire(int irq, void *dev_id)
54 pr_crit("Would Reboot\n");
63 static void watchdog_ping(void)
65 *CSR_TIMER4_LOAD = reload;
69 * Allow only one person to hold it open
71 static int watchdog_open(struct inode *inode, struct file *file)
75 if (*CSR_SA110_CNTL & (1 << 13))
78 if (test_and_set_bit(1, &timer_alive))
81 reload = soft_margin * (mem_fclk_21285 / 256);
85 *CSR_TIMER4_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD
89 ret = request_irq(IRQ_TIMER4, watchdog_fire, 0, "watchdog", NULL);
92 clear_bit(1, &timer_alive);
96 * Setting this bit is irreversible; once enabled, there is
97 * no way to disable the watchdog.
99 *CSR_SA110_CNTL |= 1 << 13;
103 nonseekable_open(inode, file);
108 * Shut off the timer.
109 * Note: if we really have enabled the watchdog, there
110 * is no way to turn off.
112 static int watchdog_release(struct inode *inode, struct file *file)
115 free_irq(IRQ_TIMER4, NULL);
116 clear_bit(1, &timer_alive);
121 static ssize_t watchdog_write(struct file *file, const char __user *data,
122 size_t len, loff_t *ppos)
133 static const struct watchdog_info ident = {
134 .options = WDIOF_SETTIMEOUT,
135 .identity = "Footbridge Watchdog",
138 static long watchdog_ioctl(struct file *file, unsigned int cmd,
141 unsigned int new_margin;
142 int __user *int_arg = (int __user *)arg;
146 case WDIOC_GETSUPPORT:
148 if (copy_to_user((void __user *)arg, &ident, sizeof(ident)))
152 case WDIOC_GETSTATUS:
153 case WDIOC_GETBOOTSTATUS:
154 ret = put_user(0, int_arg);
157 case WDIOC_KEEPALIVE:
162 case WDIOC_SETTIMEOUT:
163 ret = get_user(new_margin, int_arg);
167 /* Arbitrary, can't find the card's limits */
168 if (new_margin < 0 || new_margin > 60) {
173 soft_margin = new_margin;
174 reload = soft_margin * (mem_fclk_21285 / 256);
177 case WDIOC_GETTIMEOUT:
178 ret = put_user(soft_margin, int_arg);
184 static const struct file_operations watchdog_fops = {
185 .owner = THIS_MODULE,
187 .write = watchdog_write,
188 .unlocked_ioctl = watchdog_ioctl,
189 .open = watchdog_open,
190 .release = watchdog_release,
193 static struct miscdevice watchdog_miscdev = {
194 .minor = WATCHDOG_MINOR,
196 .fops = &watchdog_fops,
199 static int __init footbridge_watchdog_init(void)
203 if (machine_is_netwinder())
206 retval = misc_register(&watchdog_miscdev);
210 pr_info("Footbridge Watchdog Timer: 0.01, timer margin: %d sec\n",
213 if (machine_is_cats())
214 pr_warn("Warning: Watchdog reset may not work on this machine\n");
218 static void __exit footbridge_watchdog_exit(void)
220 misc_deregister(&watchdog_miscdev);
223 MODULE_AUTHOR("Phil Blundell <pb@nexus.co.uk>");
224 MODULE_DESCRIPTION("Footbridge watchdog driver");
225 MODULE_LICENSE("GPL");
226 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
228 module_param(soft_margin, int, 0);
229 MODULE_PARM_DESC(soft_margin, "Watchdog timeout in seconds");
231 module_init(footbridge_watchdog_init);
232 module_exit(footbridge_watchdog_exit);