From 43316044d4f64da008d6aca7d4b60771b9a24eb8 Mon Sep 17 00:00:00 2001 From: Wim Van Sebroeck Date: Fri, 22 Jul 2011 18:55:18 +0000 Subject: watchdog: WatchDog Timer Driver Core - Add basic framework The WatchDog Timer Driver Core is a framework that contains the common code for all watchdog-driver's. It also introduces a watchdog device structure and the operations that go with it. This is the introduction of this framework. This part supports the minimal watchdog userspace API (or with other words: the functionality to use /dev/watchdog's open, release and write functionality as defined in the simplest watchdog API). Extra functionality will follow in the next set of patches. Signed-off-by: Alan Cox Signed-off-by: Wim Van Sebroeck Acked-by: Arnd Bergmann Acked-by: Wolfram Sang --- drivers/watchdog/watchdog_core.c | 101 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 101 insertions(+) create mode 100644 drivers/watchdog/watchdog_core.c (limited to 'drivers/watchdog/watchdog_core.c') diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c new file mode 100644 index 000000000000..47fc1267ad4e --- /dev/null +++ b/drivers/watchdog/watchdog_core.c @@ -0,0 +1,101 @@ +/* + * watchdog_core.c + * + * (c) Copyright 2008-2011 Alan Cox , + * All Rights Reserved. + * + * (c) Copyright 2008-2011 Wim Van Sebroeck . + * + * 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 , + * Rob Radez , + * Rusty Lynch + * Satyam Sharma + * Randy Dunlap + * + * 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 /* For EXPORT_SYMBOL/module stuff/... */ +#include /* For standard types */ +#include /* For the -ENODEV/... values */ +#include /* For printk/panic/... */ +#include /* For watchdog specific items */ +#include /* 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; + + /* + * 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 "); +MODULE_AUTHOR("Wim Van Sebroeck "); +MODULE_DESCRIPTION("WatchDog Timer Driver Core"); +MODULE_LICENSE("GPL"); -- cgit v1.2.3 From 3f43f68e29f1dcb853d70280c7412fc0ef9a0da6 Mon Sep 17 00:00:00 2001 From: Wim Van Sebroeck Date: Fri, 22 Jul 2011 19:00:16 +0000 Subject: watchdog: WatchDog Timer Driver Core - Add minimum and max timeout 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 Signed-off-by: Wim Van Sebroeck Acked-by: Arnd Bergmann Acked-by: Wolfram Sang --- Documentation/watchdog/watchdog-kernel-api.txt | 4 ++++ drivers/watchdog/watchdog_core.c | 10 ++++++++++ drivers/watchdog/watchdog_dev.c | 3 +++ include/linux/watchdog.h | 4 ++++ 4 files changed, 21 insertions(+) (limited to 'drivers/watchdog/watchdog_core.c') diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt index 829955bd245e..4f7c894244d2 100644 --- a/Documentation/watchdog/watchdog-kernel-api.txt +++ b/Documentation/watchdog/watchdog-kernel-api.txt @@ -43,6 +43,8 @@ struct watchdog_device { const struct watchdog_ops *ops; unsigned int bootstatus; unsigned int timeout; + unsigned int min_timeout; + unsigned int max_timeout; void *driver_data; unsigned long status; }; @@ -52,6 +54,8 @@ It contains following fields: additional information about the watchdog timer itself. (Like it's unique name) * ops: a pointer to the list of watchdog operations that the watchdog supports. * timeout: the watchdog timer's timeout value (in seconds). +* min_timeout: the watchdog timer's minimum timeout value (in seconds). +* max_timeout: the watchdog timer's maximum timeout value (in seconds). * bootstatus: status of the device after booting (reported with watchdog WDIOF_* status bits). * driver_data: a pointer to the drivers private data of a watchdog device. diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c index 47fc1267ad4e..cfa1a1518aad 100644 --- a/drivers/watchdog/watchdog_core.c +++ b/drivers/watchdog/watchdog_core.c @@ -58,6 +58,16 @@ int watchdog_register_device(struct watchdog_device *wdd) 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 diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index e7134a5979c6..d33520d0b4c9 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -220,6 +220,9 @@ static long watchdog_ioctl(struct file *file, unsigned int cmd, return -EOPNOTSUPP; if (get_user(val, p)) return -EFAULT; + if ((wdd->max_timeout != 0) && + (val < wdd->min_timeout || val > wdd->max_timeout)) + return -EINVAL; err = wdd->ops->set_timeout(wdd, val); if (err < 0) return err; diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h index 325d90b6641b..111843f88b2a 100644 --- a/include/linux/watchdog.h +++ b/include/linux/watchdog.h @@ -95,6 +95,8 @@ struct watchdog_ops { * @ops: Pointer to the list of watchdog operations. * @bootstatus: Status of the watchdog device at boot. * @timeout: The watchdog devices timeout value. + * @min_timeout:The watchdog devices minimum timeout value. + * @max_timeout:The watchdog devices maximum timeout value. * @driver-data:Pointer to the drivers private data. * @status: Field that contains the devices internal status bits. * @@ -109,6 +111,8 @@ struct watchdog_device { const struct watchdog_ops *ops; unsigned int bootstatus; unsigned int timeout; + unsigned int min_timeout; + unsigned int max_timeout; void *driver_data; unsigned long status; /* Bit numbers for status flags */ -- cgit v1.2.3