2 * drivers/char/watchdog/ixp4xx_wdt.c
4 * Watchdog driver for Intel IXP4xx network processors
6 * Author: Deepak Saxena <dsaxena@plexity.net>
8 * Copyright 2004 (c) MontaVista, Software, Inc.
9 * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
11 * This file is licensed under the terms of the GNU General Public
12 * License version 2. This program is licensed "as is" without any
13 * warranty of any kind, whether express or implied.
16 #include <linux/module.h>
17 #include <linux/moduleparam.h>
18 #include <linux/types.h>
19 #include <linux/kernel.h>
21 #include <linux/miscdevice.h>
22 #include <linux/watchdog.h>
23 #include <linux/init.h>
24 #include <linux/bitops.h>
25 #include <linux/uaccess.h>
27 #include <asm/hardware.h>
29 static int nowayout = WATCHDOG_NOWAYOUT;
30 static int heartbeat = 60; /* (secs) Default is 1 minute */
31 static unsigned long wdt_status;
32 static unsigned long boot_status;
33 static spin_lock_t wdt_lock;
35 #define WDT_TICK_RATE (IXP4XX_PERIPHERAL_BUS_CLOCK * 1000000UL)
38 #define WDT_OK_TO_CLOSE 1
40 static void wdt_enable(void)
43 *IXP4XX_OSWK = IXP4XX_WDT_KEY;
45 *IXP4XX_OSWT = WDT_TICK_RATE * heartbeat;
46 *IXP4XX_OSWE = IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE;
48 spin_unlock(&wdt_lock);
51 static void wdt_disable(void)
54 *IXP4XX_OSWK = IXP4XX_WDT_KEY;
57 spin_unlock(&wdt_lock);
60 static int ixp4xx_wdt_open(struct inode *inode, struct file *file)
62 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
65 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
67 return nonseekable_open(inode, file);
71 ixp4xx_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
77 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
79 for (i = 0; i != len; i++) {
82 if (get_user(c, data + i))
85 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
93 static struct watchdog_info ident = {
94 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
95 WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
96 .identity = "IXP4xx Watchdog",
100 static long ixp4xx_wdt_ioctl(struct file *file, unsigned int cmd,
107 case WDIOC_GETSUPPORT:
108 ret = copy_to_user((struct watchdog_info *)arg, &ident,
109 sizeof(ident)) ? -EFAULT : 0;
112 case WDIOC_GETSTATUS:
113 ret = put_user(0, (int *)arg);
116 case WDIOC_GETBOOTSTATUS:
117 ret = put_user(boot_status, (int *)arg);
120 case WDIOC_KEEPALIVE:
125 case WDIOC_SETTIMEOUT:
126 ret = get_user(time, (int *)arg);
130 if (time <= 0 || time > 60) {
139 case WDIOC_GETTIMEOUT:
140 ret = put_user(heartbeat, (int *)arg);
146 static int ixp4xx_wdt_release(struct inode *inode, struct file *file)
148 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
151 printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
152 "timer will not stop\n");
153 clear_bit(WDT_IN_USE, &wdt_status);
154 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
160 static const struct file_operations ixp4xx_wdt_fops = {
161 .owner = THIS_MODULE,
163 .write = ixp4xx_wdt_write,
164 .unlocked_ioctl = ixp4xx_wdt_ioctl,
165 .open = ixp4xx_wdt_open,
166 .release = ixp4xx_wdt_release,
169 static struct miscdevice ixp4xx_wdt_miscdev = {
170 .minor = WATCHDOG_MINOR,
172 .fops = &ixp4xx_wdt_fops,
175 static int __init ixp4xx_wdt_init(void)
178 unsigned long processor_id;
180 asm("mrc p15, 0, %0, cr0, cr0, 0;" : "=r"(processor_id) :);
181 if (!(processor_id & 0xf) && !cpu_is_ixp46x()) {
182 printk(KERN_ERR "IXP4XXX Watchdog: Rev. A0 IXP42x CPU detected"
183 " - watchdog disabled\n");
187 spin_lock_init(&wdt_lock);
188 boot_status = (*IXP4XX_OSST & IXP4XX_OSST_TIMER_WARM_RESET) ?
190 ret = misc_register(&ixp4xx_wdt_miscdev);
192 printk(KERN_INFO "IXP4xx Watchdog Timer: heartbeat %d sec\n",
197 static void __exit ixp4xx_wdt_exit(void)
199 misc_deregister(&ixp4xx_wdt_miscdev);
203 module_init(ixp4xx_wdt_init);
204 module_exit(ixp4xx_wdt_exit);
206 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
207 MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog");
209 module_param(heartbeat, int, 0);
210 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
212 module_param(nowayout, int, 0);
213 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
215 MODULE_LICENSE("GPL");
216 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);