3f43f68e29
Add min_timeout (minimum timeout) and max_timeout values so that the framework can check if the new timeout value is between the minimum and maximum timeout values. If both values are 0, then the framework will leave the check for the watchdog device driver itself. Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Wim Van Sebroeck <wim@iguana.be> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Wolfram Sang <w.sang@pengutronix.de>
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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