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227 lines
4.6 KiB
227 lines
4.6 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Intel 21285 watchdog driver |
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* Copyright (c) Phil Blundell <[email protected]>, 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 <[email protected]>, |
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* All Rights Reserved. |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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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 <linux/uaccess.h> |
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#include <linux/irq.h> |
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#include <mach/hardware.h> |
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#include <asm/mach-types.h> |
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#include <asm/system_info.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) |
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{ |
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pr_crit("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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stream_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 watchdog_write(struct file *file, const char __user *data, |
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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 const 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 long watchdog_ioctl(struct file *file, unsigned int cmd, |
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unsigned long arg) |
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{ |
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int __user *int_arg = (int __user *)arg; |
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int new_margin, ret = -ENOTTY; |
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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 __user *)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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fallthrough; |
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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 const 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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.unlocked_ioctl = watchdog_ioctl, |
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.compat_ioctl = compat_ptr_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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pr_info("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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pr_warn("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 <[email protected]>"); |
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MODULE_DESCRIPTION("Footbridge watchdog driver"); |
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MODULE_LICENSE("GPL"); |
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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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