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