| /* |
| * Intel 21285 watchdog driver |
| * Copyright (c) Phil Blundell <pb@nexus.co.uk>, 1998 |
| * |
| * based on |
| * |
| * SoftDog 0.05: A Software Watchdog Device |
| * |
| * (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved. |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation; either version |
| * 2 of the License, or (at your option) any later version. |
| * |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/moduleparam.h> |
| #include <linux/types.h> |
| #include <linux/kernel.h> |
| #include <linux/fs.h> |
| #include <linux/mm.h> |
| #include <linux/miscdevice.h> |
| #include <linux/watchdog.h> |
| #include <linux/reboot.h> |
| #include <linux/init.h> |
| #include <linux/interrupt.h> |
| |
| #include <asm/irq.h> |
| #include <asm/uaccess.h> |
| #include <mach/hardware.h> |
| #include <asm/mach-types.h> |
| #include <asm/hardware/dec21285.h> |
| |
| /* |
| * Define this to stop the watchdog actually rebooting the machine. |
| */ |
| #undef ONLY_TESTING |
| |
| static unsigned int soft_margin = 60; /* in seconds */ |
| static unsigned int reload; |
| static unsigned long timer_alive; |
| |
| #ifdef ONLY_TESTING |
| /* |
| * If the timer expires.. |
| */ |
| static void watchdog_fire(int irq, void *dev_id) |
| { |
| printk(KERN_CRIT "Watchdog: Would Reboot.\n"); |
| *CSR_TIMER4_CNTL = 0; |
| *CSR_TIMER4_CLR = 0; |
| } |
| #endif |
| |
| /* |
| * Refresh the timer. |
| */ |
| static void watchdog_ping(void) |
| { |
| *CSR_TIMER4_LOAD = reload; |
| } |
| |
| /* |
| * Allow only one person to hold it open |
| */ |
| static int watchdog_open(struct inode *inode, struct file *file) |
| { |
| int ret; |
| |
| if (*CSR_SA110_CNTL & (1 << 13)) |
| return -EBUSY; |
| |
| if (test_and_set_bit(1, &timer_alive)) |
| return -EBUSY; |
| |
| reload = soft_margin * (mem_fclk_21285 / 256); |
| |
| *CSR_TIMER4_CLR = 0; |
| watchdog_ping(); |
| *CSR_TIMER4_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD |
| | TIMER_CNTL_DIV256; |
| |
| #ifdef ONLY_TESTING |
| ret = request_irq(IRQ_TIMER4, watchdog_fire, 0, "watchdog", NULL); |
| if (ret) { |
| *CSR_TIMER4_CNTL = 0; |
| clear_bit(1, &timer_alive); |
| } |
| #else |
| /* |
| * Setting this bit is irreversible; once enabled, there is |
| * no way to disable the watchdog. |
| */ |
| *CSR_SA110_CNTL |= 1 << 13; |
| |
| ret = 0; |
| #endif |
| nonseekable_open(inode, file); |
| return ret; |
| } |
| |
| /* |
| * Shut off the timer. |
| * Note: if we really have enabled the watchdog, there |
| * is no way to turn off. |
| */ |
| static int watchdog_release(struct inode *inode, struct file *file) |
| { |
| #ifdef ONLY_TESTING |
| free_irq(IRQ_TIMER4, NULL); |
| clear_bit(1, &timer_alive); |
| #endif |
| return 0; |
| } |
| |
| static ssize_t |
| watchdog_write(struct file *file, const char *data, size_t len, loff_t *ppos) |
| { |
| /* |
| * Refresh the timer. |
| */ |
| if (len) |
| watchdog_ping(); |
| |
| return len; |
| } |
| |
| static struct watchdog_info ident = { |
| .options = WDIOF_SETTIMEOUT, |
| .identity = "Footbridge Watchdog", |
| }; |
| |
| static int |
| watchdog_ioctl(struct inode *inode, struct file *file, unsigned int cmd, |
| unsigned long arg) |
| { |
| unsigned int new_margin; |
| int ret = -ENOTTY; |
| |
| switch(cmd) { |
| case WDIOC_GETSUPPORT: |
| ret = 0; |
| if (copy_to_user((void *)arg, &ident, sizeof(ident))) |
| ret = -EFAULT; |
| break; |
| |
| case WDIOC_GETSTATUS: |
| case WDIOC_GETBOOTSTATUS: |
| ret = put_user(0,(int *)arg); |
| break; |
| |
| case WDIOC_KEEPALIVE: |
| watchdog_ping(); |
| ret = 0; |
| break; |
| |
| case WDIOC_SETTIMEOUT: |
| ret = get_user(new_margin, (int *)arg); |
| if (ret) |
| break; |
| |
| /* Arbitrary, can't find the card's limits */ |
| if (new_margin < 0 || new_margin > 60) { |
| ret = -EINVAL; |
| break; |
| } |
| |
| soft_margin = new_margin; |
| reload = soft_margin * (mem_fclk_21285 / 256); |
| watchdog_ping(); |
| /* Fall */ |
| case WDIOC_GETTIMEOUT: |
| ret = put_user(soft_margin, (int *)arg); |
| break; |
| } |
| return ret; |
| } |
| |
| static const struct file_operations watchdog_fops = { |
| .owner = THIS_MODULE, |
| .llseek = no_llseek, |
| .write = watchdog_write, |
| .ioctl = watchdog_ioctl, |
| .open = watchdog_open, |
| .release = watchdog_release, |
| }; |
| |
| static struct miscdevice watchdog_miscdev = { |
| .minor = WATCHDOG_MINOR, |
| .name = "watchdog", |
| .fops = &watchdog_fops, |
| }; |
| |
| static int __init footbridge_watchdog_init(void) |
| { |
| int retval; |
| |
| if (machine_is_netwinder()) |
| return -ENODEV; |
| |
| retval = misc_register(&watchdog_miscdev); |
| if (retval < 0) |
| return retval; |
| |
| printk("Footbridge Watchdog Timer: 0.01, timer margin: %d sec\n", |
| soft_margin); |
| |
| if (machine_is_cats()) |
| printk("Warning: Watchdog reset may not work on this machine.\n"); |
| return 0; |
| } |
| |
| static void __exit footbridge_watchdog_exit(void) |
| { |
| misc_deregister(&watchdog_miscdev); |
| } |
| |
| MODULE_AUTHOR("Phil Blundell <pb@nexus.co.uk>"); |
| MODULE_DESCRIPTION("Footbridge watchdog driver"); |
| MODULE_LICENSE("GPL"); |
| MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
| |
| module_param(soft_margin, int, 0); |
| MODULE_PARM_DESC(soft_margin,"Watchdog timeout in seconds"); |
| |
| module_init(footbridge_watchdog_init); |
| module_exit(footbridge_watchdog_exit); |