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authorWim Van Sebroeck <wim@iguana.be>2011-07-22 18:55:18 +0000
committerWim Van Sebroeck <wim@iguana.be>2011-07-28 08:01:04 +0000
commit43316044d4f64da008d6aca7d4b60771b9a24eb8 (patch)
tree66d0d023a8713119d973e3c367efa21fb5a1908f /drivers/watchdog/watchdog_core.c
parent5efc7a6222f6408d29d6beb1142a302f31dc9eac (diff)
downloadlinux-43316044d4f64da008d6aca7d4b60771b9a24eb8.tar.bz2
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 <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>
Diffstat (limited to 'drivers/watchdog/watchdog_core.c')
-rw-r--r--drivers/watchdog/watchdog_core.c101
1 files changed, 101 insertions, 0 deletions
diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
new file mode 100644
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+++ b/drivers/watchdog/watchdog_core.c
@@ -0,0 +1,101 @@
+/*
+ * 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;
+
+ /*
+ * 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");