112 lines
3.3 KiB
C
112 lines
3.3 KiB
C
/*
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* watchdog_core.c
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*
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* (c) Copyright 2008-2011 Alan Cox <alan@lxorguk.ukuu.org.uk>,
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* All Rights Reserved.
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*
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* (c) Copyright 2008-2011 Wim Van Sebroeck <wim@iguana.be>.
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*
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* This source code is part of the generic code that can be used
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* by all the watchdog timer drivers.
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*
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* Based on source code of the following authors:
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* Matt Domsch <Matt_Domsch@dell.com>,
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* Rob Radez <rob@osinvestor.com>,
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* Rusty Lynch <rusty@linux.co.intel.com>
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* Satyam Sharma <satyam@infradead.org>
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* Randy Dunlap <randy.dunlap@oracle.com>
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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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* Neither Alan Cox, CymruNet Ltd., Wim Van Sebroeck nor Iguana vzw.
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* admit liability nor provide warranty for any of this software.
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* This material is provided "AS-IS" and at no charge.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h> /* For EXPORT_SYMBOL/module stuff/... */
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#include <linux/types.h> /* For standard types */
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#include <linux/errno.h> /* For the -ENODEV/... values */
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#include <linux/kernel.h> /* For printk/panic/... */
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#include <linux/watchdog.h> /* For watchdog specific items */
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#include <linux/init.h> /* For __init/__exit/... */
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#include "watchdog_dev.h" /* For watchdog_dev_register/... */
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/**
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* watchdog_register_device() - register a watchdog device
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* @wdd: watchdog device
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*
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* Register a watchdog device with the kernel so that the
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* watchdog timer can be accessed from userspace.
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*
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* A zero is returned on success and a negative errno code for
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* failure.
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*/
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int watchdog_register_device(struct watchdog_device *wdd)
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{
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int ret;
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if (wdd == NULL || wdd->info == NULL || wdd->ops == NULL)
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return -EINVAL;
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/* Mandatory operations need to be supported */
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if (wdd->ops->start == NULL || wdd->ops->stop == NULL)
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return -EINVAL;
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/*
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* Check that we have valid min and max timeout values, if
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* not reset them both to 0 (=not used or unknown)
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*/
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if (wdd->min_timeout > wdd->max_timeout) {
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pr_info("Invalid min and max timeout values, resetting to 0!\n");
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wdd->min_timeout = 0;
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wdd->max_timeout = 0;
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}
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/*
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* Note: now that all watchdog_device data has been verified, we
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* will not check this anymore in other functions. If data gets
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* corrupted in a later stage then we expect a kernel panic!
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*/
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/* We only support 1 watchdog device via the /dev/watchdog interface */
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ret = watchdog_dev_register(wdd);
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if (ret) {
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pr_err("error registering /dev/watchdog (err=%d).\n", ret);
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return ret;
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(watchdog_register_device);
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/**
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* watchdog_unregister_device() - unregister a watchdog device
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* @wdd: watchdog device to unregister
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*
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* Unregister a watchdog device that was previously successfully
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* registered with watchdog_register_device().
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*/
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void watchdog_unregister_device(struct watchdog_device *wdd)
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{
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int ret;
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if (wdd == NULL)
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return;
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ret = watchdog_dev_unregister(wdd);
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if (ret)
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pr_err("error unregistering /dev/watchdog (err=%d).\n", ret);
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}
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EXPORT_SYMBOL_GPL(watchdog_unregister_device);
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MODULE_AUTHOR("Alan Cox <alan@lxorguk.ukuu.org.uk>");
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MODULE_AUTHOR("Wim Van Sebroeck <wim@iguana.be>");
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MODULE_DESCRIPTION("WatchDog Timer Driver Core");
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MODULE_LICENSE("GPL");
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