/* * drivers/char/watchdog/ixp4xx_wdt.c * * Watchdog driver for Intel IXP4xx network processors * * 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 <asm/hardware.h> #include <asm/uaccess.h> static int nowayout = WATCHDOG_NOWAYOUT; static int heartbeat = 60; /* (secs) Default is 1 minute */ static unsigned long wdt_status; static unsigned long boot_status; #define WDT_TICK_RATE (IXP4XX_PERIPHERAL_BUS_CLOCK * 1000000UL) #define WDT_IN_USE 0 #define WDT_OK_TO_CLOSE 1 static void wdt_enable(void) { *IXP4XX_OSWK = IXP4XX_WDT_KEY; *IXP4XX_OSWE = 0; *IXP4XX_OSWT = WDT_TICK_RATE * heartbeat; *IXP4XX_OSWE = IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE; *IXP4XX_OSWK = 0; } static void wdt_disable(void) { *IXP4XX_OSWK = IXP4XX_WDT_KEY; *IXP4XX_OSWE = 0; *IXP4XX_OSWK = 0; } static int ixp4xx_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 ixp4xx_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_enable(); } return len; } static struct watchdog_info ident = { .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, .identity = "IXP4xx Watchdog", }; static int ixp4xx_wdt_ioctl(struct inode *inode, 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(boot_status, (int *)arg); break; case WDIOC_SETTIMEOUT: ret = get_user(time, (int *)arg); if (ret) break; if (time <= 0 || time > 60) { ret = -EINVAL; break; } heartbeat = time; wdt_enable(); /* Fall through */ case WDIOC_GETTIMEOUT: ret = put_user(heartbeat, (int *)arg); break; case WDIOC_KEEPALIVE: wdt_enable(); ret = 0; break; } return ret; } static int ixp4xx_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 ixp4xx_wdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = ixp4xx_wdt_write, .ioctl = ixp4xx_wdt_ioctl, .open = ixp4xx_wdt_open, .release = ixp4xx_wdt_release, }; static struct miscdevice ixp4xx_wdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &ixp4xx_wdt_fops, }; static int __init ixp4xx_wdt_init(void) { int ret; unsigned long processor_id; asm("mrc p15, 0, %0, cr0, cr0, 0;" : "=r"(processor_id) :); if (!(processor_id & 0xf) && !cpu_is_ixp46x()) { printk("IXP4XXX Watchdog: Rev. A0 IXP42x CPU detected - " "watchdog disabled\n"); return -ENODEV; } ret = misc_register(&ixp4xx_wdt_miscdev); if (ret == 0) printk("IXP4xx Watchdog Timer: heartbeat %d sec\n", heartbeat); boot_status = (*IXP4XX_OSST & IXP4XX_OSST_TIMER_WARM_RESET) ? WDIOF_CARDRESET : 0; return ret; } static void __exit ixp4xx_wdt_exit(void) { misc_deregister(&ixp4xx_wdt_miscdev); } module_init(ixp4xx_wdt_init); module_exit(ixp4xx_wdt_exit); MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>"); MODULE_DESCRIPTION("IXP4xx 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);