2 * drivers/char/watchdog/ixp2000_wdt.c
4 * Watchdog driver for Intel IXP2000 network processors
6 * Adapted from the IXP4xx watchdog driver by Lennert Buytenhek.
7 * The original version carries these notices:
9 * Author: Deepak Saxena <dsaxena@plexity.net>
11 * Copyright 2004 (c) MontaVista, Software, Inc.
12 * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
14 * This file is licensed under the terms of the GNU General Public
15 * License version 2. This program is licensed "as is" without any
16 * warranty of any kind, whether express or implied.
19 #include <linux/module.h>
20 #include <linux/moduleparam.h>
21 #include <linux/types.h>
22 #include <linux/timer.h>
23 #include <linux/kernel.h>
25 #include <linux/miscdevice.h>
26 #include <linux/watchdog.h>
27 #include <linux/init.h>
28 #include <linux/bitops.h>
29 #include <linux/uaccess.h>
30 #include <mach/hardware.h>
32 static int nowayout = WATCHDOG_NOWAYOUT;
33 static unsigned int heartbeat = 60; /* (secs) Default is 1 minute */
34 static unsigned long wdt_status;
35 static spinlock_t wdt_lock;
38 #define WDT_OK_TO_CLOSE 1
40 static unsigned long wdt_tick_rate;
42 static void wdt_enable(void)
45 ixp2000_reg_write(IXP2000_RESET0, *(IXP2000_RESET0) | WDT_RESET_ENABLE);
46 ixp2000_reg_write(IXP2000_TWDE, WDT_ENABLE);
47 ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
48 ixp2000_reg_write(IXP2000_T4_CTL, TIMER_DIVIDER_256 | TIMER_ENABLE);
49 spin_unlock(&wdt_lock);
52 static void wdt_disable(void)
55 ixp2000_reg_write(IXP2000_T4_CTL, 0);
56 spin_unlock(&wdt_lock);
59 static void wdt_keepalive(void)
62 ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
63 spin_unlock(&wdt_lock);
66 static int ixp2000_wdt_open(struct inode *inode, struct file *file)
68 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
71 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
75 return nonseekable_open(inode, file);
78 static ssize_t ixp2000_wdt_write(struct file *file, const char *data,
79 size_t len, loff_t *ppos)
85 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
87 for (i = 0; i != len; i++) {
90 if (get_user(c, data + i))
93 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
103 static struct watchdog_info ident = {
104 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
106 .identity = "IXP2000 Watchdog",
109 static long ixp2000_wdt_ioctl(struct file *file, unsigned int cmd,
116 case WDIOC_GETSUPPORT:
117 ret = copy_to_user((struct watchdog_info *)arg, &ident,
118 sizeof(ident)) ? -EFAULT : 0;
121 case WDIOC_GETSTATUS:
122 ret = put_user(0, (int *)arg);
125 case WDIOC_GETBOOTSTATUS:
126 ret = put_user(0, (int *)arg);
129 case WDIOC_KEEPALIVE:
134 case WDIOC_SETTIMEOUT:
135 ret = get_user(time, (int *)arg);
139 if (time <= 0 || time > 60) {
148 case WDIOC_GETTIMEOUT:
149 ret = put_user(heartbeat, (int *)arg);
156 static int ixp2000_wdt_release(struct inode *inode, struct file *file)
158 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
161 printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
162 "timer will not stop\n");
163 clear_bit(WDT_IN_USE, &wdt_status);
164 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
170 static const struct file_operations ixp2000_wdt_fops = {
171 .owner = THIS_MODULE,
173 .write = ixp2000_wdt_write,
174 .unlocked_ioctl = ixp2000_wdt_ioctl,
175 .open = ixp2000_wdt_open,
176 .release = ixp2000_wdt_release,
179 static struct miscdevice ixp2000_wdt_miscdev = {
180 .minor = WATCHDOG_MINOR,
182 .fops = &ixp2000_wdt_fops,
185 static int __init ixp2000_wdt_init(void)
187 if ((*IXP2000_PRODUCT_ID & 0x001ffef0) == 0x00000000) {
188 printk(KERN_INFO "Unable to use IXP2000 watchdog due to IXP2800 erratum #25.\n");
191 wdt_tick_rate = (*IXP2000_T1_CLD * HZ) / 256;
192 spin_lock_init(&wdt_lock);
193 return misc_register(&ixp2000_wdt_miscdev);
196 static void __exit ixp2000_wdt_exit(void)
198 misc_deregister(&ixp2000_wdt_miscdev);
201 module_init(ixp2000_wdt_init);
202 module_exit(ixp2000_wdt_exit);
204 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
205 MODULE_DESCRIPTION("IXP2000 Network Processor Watchdog");
207 module_param(heartbeat, int, 0);
208 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
210 module_param(nowayout, int, 0);
211 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
213 MODULE_LICENSE("GPL");
214 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);