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/system_info.h>
38 #include <asm/hardware/dec21285.h>
41 * Define this to stop the watchdog actually rebooting the machine.
45 static unsigned int soft_margin = 60; /* in seconds */
46 static unsigned int reload;
47 static unsigned long timer_alive;
51 * If the timer expires..
53 static void watchdog_fire(int irq, void *dev_id)
55 pr_crit("Would Reboot\n");
64 static void watchdog_ping(void)
66 *CSR_TIMER4_LOAD = reload;
70 * Allow only one person to hold it open
72 static int watchdog_open(struct inode *inode, struct file *file)
76 if (*CSR_SA110_CNTL & (1 << 13))
79 if (test_and_set_bit(1, &timer_alive))
82 reload = soft_margin * (mem_fclk_21285 / 256);
86 *CSR_TIMER4_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD
90 ret = request_irq(IRQ_TIMER4, watchdog_fire, 0, "watchdog", NULL);
93 clear_bit(1, &timer_alive);
97 * Setting this bit is irreversible; once enabled, there is
98 * no way to disable the watchdog.
100 *CSR_SA110_CNTL |= 1 << 13;
104 nonseekable_open(inode, file);
109 * Shut off the timer.
110 * Note: if we really have enabled the watchdog, there
111 * is no way to turn off.
113 static int watchdog_release(struct inode *inode, struct file *file)
116 free_irq(IRQ_TIMER4, NULL);
117 clear_bit(1, &timer_alive);
122 static ssize_t watchdog_write(struct file *file, const char __user *data,
123 size_t len, loff_t *ppos)
134 static const struct watchdog_info ident = {
135 .options = WDIOF_SETTIMEOUT,
136 .identity = "Footbridge Watchdog",
139 static long watchdog_ioctl(struct file *file, unsigned int cmd,
142 unsigned int new_margin;
143 int __user *int_arg = (int __user *)arg;
147 case WDIOC_GETSUPPORT:
149 if (copy_to_user((void __user *)arg, &ident, sizeof(ident)))
153 case WDIOC_GETSTATUS:
154 case WDIOC_GETBOOTSTATUS:
155 ret = put_user(0, int_arg);
158 case WDIOC_KEEPALIVE:
163 case WDIOC_SETTIMEOUT:
164 ret = get_user(new_margin, int_arg);
168 /* Arbitrary, can't find the card's limits */
169 if (new_margin < 0 || new_margin > 60) {
174 soft_margin = new_margin;
175 reload = soft_margin * (mem_fclk_21285 / 256);
178 case WDIOC_GETTIMEOUT:
179 ret = put_user(soft_margin, int_arg);
185 static const struct file_operations watchdog_fops = {
186 .owner = THIS_MODULE,
188 .write = watchdog_write,
189 .unlocked_ioctl = watchdog_ioctl,
190 .open = watchdog_open,
191 .release = watchdog_release,
194 static struct miscdevice watchdog_miscdev = {
195 .minor = WATCHDOG_MINOR,
197 .fops = &watchdog_fops,
200 static int __init footbridge_watchdog_init(void)
204 if (machine_is_netwinder())
207 retval = misc_register(&watchdog_miscdev);
211 pr_info("Footbridge Watchdog Timer: 0.01, timer margin: %d sec\n",
214 if (machine_is_cats())
215 pr_warn("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);