/* * drivers/char/watchdog/ixp2000_wdt.c * * Watchdog driver for Intel IXP2000 network processors * * Adapted from the IXP4xx watchdog driver by Lennert Buytenhek. * The original version carries these notices: * * Author: Deepak Saxena <dsaxena@plexity.net> * * Copyright 2004 (c) MontaVista, Software, Inc. * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu> * * This file is licensed under the terms of the GNU General Public * License version 2. This program is licensed "as is" without any * warranty of any kind, whether express or implied. */ #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/types.h> #include <linux/kernel.h> #include <linux/fs.h> #include <linux/miscdevice.h> #include <linux/watchdog.h> #include <linux/init.h> #include <linux/bitops.h> #include <linux/uaccess.h> #include <mach/hardware.h> static int nowayout = WATCHDOG_NOWAYOUT; static unsigned int heartbeat = 60; /* (secs) Default is 1 minute */ static unsigned long wdt_status; static spinlock_t wdt_lock; #define WDT_IN_USE 0 #define WDT_OK_TO_CLOSE 1 static unsigned long wdt_tick_rate; static void wdt_enable(void) { spin_lock(&wdt_lock); ixp2000_reg_write(IXP2000_RESET0, *(IXP2000_RESET0) | WDT_RESET_ENABLE); ixp2000_reg_write(IXP2000_TWDE, WDT_ENABLE); ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate); ixp2000_reg_write(IXP2000_T4_CTL, TIMER_DIVIDER_256 | TIMER_ENABLE); spin_unlock(&wdt_lock); } static void wdt_disable(void) { spin_lock(&wdt_lock); ixp2000_reg_write(IXP2000_T4_CTL, 0); spin_unlock(&wdt_lock); } static void wdt_keepalive(void) { spin_lock(&wdt_lock); ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate); spin_unlock(&wdt_lock); } static int ixp2000_wdt_open(struct inode *inode, struct file *file) { if (test_and_set_bit(WDT_IN_USE, &wdt_status)) return -EBUSY; clear_bit(WDT_OK_TO_CLOSE, &wdt_status); wdt_enable(); return nonseekable_open(inode, file); } static ssize_t ixp2000_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos) { if (len) { if (!nowayout) { size_t i; clear_bit(WDT_OK_TO_CLOSE, &wdt_status); for (i = 0; i != len; i++) { char c; if (get_user(c, data + i)) return -EFAULT; if (c == 'V') set_bit(WDT_OK_TO_CLOSE, &wdt_status); } } wdt_keepalive(); } return len; } static struct watchdog_info ident = { .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, .identity = "IXP2000 Watchdog", }; static long ixp2000_wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { int ret = -ENOTTY; int time; switch (cmd) { case WDIOC_GETSUPPORT: ret = copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident)) ? -EFAULT : 0; break; case WDIOC_GETSTATUS: ret = put_user(0, (int *)arg); break; case WDIOC_GETBOOTSTATUS: ret = put_user(0, (int *)arg); break; case WDIOC_KEEPALIVE: wdt_enable(); ret = 0; break; case WDIOC_SETTIMEOUT: ret = get_user(time, (int *)arg); if (ret) break; if (time <= 0 || time > 60) { ret = -EINVAL; break; } heartbeat = time; wdt_keepalive(); /* Fall through */ case WDIOC_GETTIMEOUT: ret = put_user(heartbeat, (int *)arg); break; } return ret; } static int ixp2000_wdt_release(struct inode *inode, struct file *file) { if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) wdt_disable(); else printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - " "timer will not stop\n"); clear_bit(WDT_IN_USE, &wdt_status); clear_bit(WDT_OK_TO_CLOSE, &wdt_status); return 0; } static const struct file_operations ixp2000_wdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = ixp2000_wdt_write, .unlocked_ioctl = ixp2000_wdt_ioctl, .open = ixp2000_wdt_open, .release = ixp2000_wdt_release, }; static struct miscdevice ixp2000_wdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &ixp2000_wdt_fops, }; static int __init ixp2000_wdt_init(void) { if ((*IXP2000_PRODUCT_ID & 0x001ffef0) == 0x00000000) { printk(KERN_INFO "Unable to use IXP2000 watchdog due to IXP2800 erratum #25.\n"); return -EIO; } wdt_tick_rate = (*IXP2000_T1_CLD * HZ) / 256; spin_lock_init(&wdt_lock); return misc_register(&ixp2000_wdt_miscdev); } static void __exit ixp2000_wdt_exit(void) { misc_deregister(&ixp2000_wdt_miscdev); } module_init(ixp2000_wdt_init); module_exit(ixp2000_wdt_exit); MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>"); MODULE_DESCRIPTION("IXP2000 Network Processor Watchdog"); module_param(heartbeat, int, 0); MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)"); module_param(nowayout, int, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); MODULE_LICENSE("GPL"); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);