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