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@redhat.com>, All Rights Reserved.
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation; either version
14 * 2 of the License, or (at your option) any later version.
18 #include <linux/module.h>
19 #include <linux/moduleparam.h>
20 #include <linux/types.h>
21 #include <linux/kernel.h>
24 #include <linux/miscdevice.h>
25 #include <linux/watchdog.h>
26 #include <linux/reboot.h>
27 #include <linux/init.h>
28 #include <linux/interrupt.h>
31 #include <asm/uaccess.h>
32 #include <asm/hardware.h>
33 #include <asm/mach-types.h>
34 #include <asm/hardware/dec21285.h>
37 * Define this to stop the watchdog actually rebooting the machine.
41 static unsigned int soft_margin = 60; /* in seconds */
42 static unsigned int reload;
43 static unsigned long timer_alive;
47 * If the timer expires..
49 static void watchdog_fire(int irq, void *dev_id, struct pt_regs *regs)
51 printk(KERN_CRIT "Watchdog: Would Reboot.\n");
60 static void watchdog_ping(void)
62 *CSR_TIMER4_LOAD = reload;
66 * Allow only one person to hold it open
68 static int watchdog_open(struct inode *inode, struct file *file)
72 if (*CSR_SA110_CNTL & (1 << 13))
75 if (test_and_set_bit(1, &timer_alive))
78 reload = soft_margin * (mem_fclk_21285 / 256);
82 *CSR_TIMER4_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD
86 ret = request_irq(IRQ_TIMER4, watchdog_fire, 0, "watchdog", NULL);
89 clear_bit(1, &timer_alive);
93 * Setting this bit is irreversible; once enabled, there is
94 * no way to disable the watchdog.
96 *CSR_SA110_CNTL |= 1 << 13;
104 * Shut off the timer.
105 * Note: if we really have enabled the watchdog, there
106 * is no way to turn off.
108 static int watchdog_release(struct inode *inode, struct file *file)
111 free_irq(IRQ_TIMER4, NULL);
112 clear_bit(1, &timer_alive);
118 watchdog_write(struct file *file, const char *data, size_t len, loff_t *ppos)
120 /* Can't seek (pwrite) on this device */
121 if (ppos != &file->f_pos)
133 static struct watchdog_info ident = {
134 .options = WDIOF_SETTIMEOUT,
135 .identity = "Footbridge Watchdog",
139 watchdog_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
142 unsigned int new_margin;
143 int ret = -ENOIOCTLCMD;
146 case WDIOC_GETSUPPORT:
148 if (copy_to_user((void *)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 struct file_operations watchdog_fops = {
185 .owner = THIS_MODULE,
186 .write = watchdog_write,
187 .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);
209 printk("Footbridge Watchdog Timer: 0.01, timer margin: %d sec\n",
212 if (machine_is_cats())
213 printk("Warning: Watchdog reset may not work on this machine.\n");
217 static void __exit footbridge_watchdog_exit(void)
219 misc_deregister(&watchdog_miscdev);
222 MODULE_AUTHOR("Phil Blundell <pb@nexus.co.uk>");
223 MODULE_DESCRIPTION("Footbridge watchdog driver");
224 MODULE_LICENSE("GPL");
225 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
227 module_param(soft_margin, int, 0);
228 MODULE_PARM_DESC(soft_margin,"Watchdog timeout in seconds");
230 module_init(footbridge_watchdog_init);
231 module_exit(footbridge_watchdog_exit);