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* drivers/char/watchdog/ixp4xx_wdt.c
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* Watchdog driver for Intel IXP4xx network processors
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* Author: Deepak Saxena <dsaxena@plexity.net>
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* Copyright 2004 (c) MontaVista, Software, Inc.
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* Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
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* This file is licensed under the terms of the GNU General Public
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* License version 2. This program is licensed "as is" without any
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* warranty of any kind, whether express or implied.
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/miscdevice.h>
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#include <linux/watchdog.h>
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#include <linux/init.h>
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#include <linux/bitops.h>
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#include <linux/uaccess.h>
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#include <mach/hardware.h>
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static int nowayout = WATCHDOG_NOWAYOUT;
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static int heartbeat = 60; /* (secs) Default is 1 minute */
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static unsigned long wdt_status;
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static unsigned long boot_status;
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static DEFINE_SPINLOCK(wdt_lock);
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#define WDT_TICK_RATE (IXP4XX_PERIPHERAL_BUS_CLOCK * 1000000UL)
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#define WDT_OK_TO_CLOSE 1
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static void wdt_enable(void)
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*IXP4XX_OSWK = IXP4XX_WDT_KEY;
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*IXP4XX_OSWT = WDT_TICK_RATE * heartbeat;
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*IXP4XX_OSWE = IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE;
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spin_unlock(&wdt_lock);
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static void wdt_disable(void)
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*IXP4XX_OSWK = IXP4XX_WDT_KEY;
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spin_unlock(&wdt_lock);
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static int ixp4xx_wdt_open(struct inode *inode, struct file *file)
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if (test_and_set_bit(WDT_IN_USE, &wdt_status))
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clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
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return nonseekable_open(inode, file);
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ixp4xx_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
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clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
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for (i = 0; i != len; i++) {
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if (get_user(c, data + i))
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set_bit(WDT_OK_TO_CLOSE, &wdt_status);
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static const struct watchdog_info ident = {
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.options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
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WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
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.identity = "IXP4xx Watchdog",
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static long ixp4xx_wdt_ioctl(struct file *file, unsigned int cmd,
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case WDIOC_GETSUPPORT:
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ret = copy_to_user((struct watchdog_info *)arg, &ident,
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sizeof(ident)) ? -EFAULT : 0;
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case WDIOC_GETSTATUS:
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ret = put_user(0, (int *)arg);
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case WDIOC_GETBOOTSTATUS:
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ret = put_user(boot_status, (int *)arg);
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case WDIOC_KEEPALIVE:
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case WDIOC_SETTIMEOUT:
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ret = get_user(time, (int *)arg);
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if (time <= 0 || time > 60) {
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case WDIOC_GETTIMEOUT:
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ret = put_user(heartbeat, (int *)arg);
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static int ixp4xx_wdt_release(struct inode *inode, struct file *file)
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if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
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printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
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"timer will not stop\n");
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clear_bit(WDT_IN_USE, &wdt_status);
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clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
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static const struct file_operations ixp4xx_wdt_fops = {
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.owner = THIS_MODULE,
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.write = ixp4xx_wdt_write,
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.unlocked_ioctl = ixp4xx_wdt_ioctl,
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.open = ixp4xx_wdt_open,
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.release = ixp4xx_wdt_release,
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static struct miscdevice ixp4xx_wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.fops = &ixp4xx_wdt_fops,
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static int __init ixp4xx_wdt_init(void)
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if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) {
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printk(KERN_ERR "IXP4XXX Watchdog: Rev. A0 IXP42x CPU detected"
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" - watchdog disabled\n");
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spin_lock_init(&wdt_lock);
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boot_status = (*IXP4XX_OSST & IXP4XX_OSST_TIMER_WARM_RESET) ?
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ret = misc_register(&ixp4xx_wdt_miscdev);
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printk(KERN_INFO "IXP4xx Watchdog Timer: heartbeat %d sec\n",
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static void __exit ixp4xx_wdt_exit(void)
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misc_deregister(&ixp4xx_wdt_miscdev);
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module_init(ixp4xx_wdt_init);
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module_exit(ixp4xx_wdt_exit);
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MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
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MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog");
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module_param(heartbeat, int, 0);
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MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
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module_param(nowayout, int, 0);
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);