[linux-2.6-block.git] / drivers / watchdog / watchdog_core.c

/*
 *	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/reboot.h>	/* For restart handler */
#include <linux/watchdog.h>	/* For watchdog specific items */
#include <linux/init.h>		/* For __init/__exit/... */
#include <linux/idr.h>		/* For ida_* macros */
#include <linux/err.h>		/* For IS_ERR macros */
#include <linux/of.h>		/* For of_get_timeout_sec */

#include "watchdog_core.h"	/* For watchdog_dev_register/... */

static DEFINE_IDA(watchdog_ida);

/*
 * Deferred Registration infrastructure.
 *
 * Sometimes watchdog drivers needs to be loaded as soon as possible,
 * for example when it's impossible to disable it. To do so,
 * raising the initcall level of the watchdog driver is a solution.
 * But in such case, the miscdev is maybe not ready (subsys_initcall), and
 * watchdog_core need miscdev to register the watchdog as a char device.
 *
 * The deferred registration infrastructure offer a way for the watchdog
 * subsystem to register a watchdog properly, even before miscdev is ready.
 */

static DEFINE_MUTEX(wtd_deferred_reg_mutex);
static LIST_HEAD(wtd_deferred_reg_list);
static bool wtd_deferred_reg_done;

static int watchdog_deferred_registration_add(struct watchdog_device *wdd)
{
	list_add_tail(&wdd->deferred,
		      &wtd_deferred_reg_list);
	return 0;
}

static void watchdog_deferred_registration_del(struct watchdog_device *wdd)
{
	struct list_head *p, *n;
	struct watchdog_device *wdd_tmp;

	list_for_each_safe(p, n, &wtd_deferred_reg_list) {
		wdd_tmp = list_entry(p, struct watchdog_device,
				     deferred);
		if (wdd_tmp == wdd) {
			list_del(&wdd_tmp->deferred);
			break;
		}
	}
}

static void watchdog_check_min_max_timeout(struct watchdog_device *wdd)
{
	/*
	 * 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;
	}
}

/**
 * watchdog_init_timeout() - initialize the timeout field
 * @timeout_parm: timeout module parameter
 * @dev: Device that stores the timeout-sec property
 *
 * Initialize the timeout field of the watchdog_device struct with either the
 * timeout module parameter (if it is valid value) or the timeout-sec property
 * (only if it is a valid value and the timeout_parm is out of bounds).
 * If none of them are valid then we keep the old value (which should normally
 * be the default timeout value.
 *
 * A zero is returned on success and -EINVAL for failure.
 */
int watchdog_init_timeout(struct watchdog_device *wdd,
				unsigned int timeout_parm, struct device *dev)
{
	unsigned int t = 0;
	int ret = 0;

	watchdog_check_min_max_timeout(wdd);

	/* try to get the timeout module parameter first */
	if (!watchdog_timeout_invalid(wdd, timeout_parm) && timeout_parm) {
		wdd->timeout = timeout_parm;
		return ret;
	}
	if (timeout_parm)
		ret = -EINVAL;

	/* try to get the timeout_sec property */
	if (dev == NULL || dev->of_node == NULL)
		return ret;
	of_property_read_u32(dev->of_node, "timeout-sec", &t);
	if (!watchdog_timeout_invalid(wdd, t) && t)
		wdd->timeout = t;
	else
		ret = -EINVAL;

	return ret;
}
EXPORT_SYMBOL_GPL(watchdog_init_timeout);

static int watchdog_reboot_notifier(struct notifier_block *nb,
				    unsigned long code, void *data)
{
	struct watchdog_device *wdd = container_of(nb, struct watchdog_device,
						   reboot_nb);

	if (code == SYS_DOWN || code == SYS_HALT) {
		if (watchdog_active(wdd)) {
			int ret;

			ret = wdd->ops->stop(wdd);
			if (ret)
				return NOTIFY_BAD;
		}
	}

	return NOTIFY_DONE;
}

static int watchdog_restart_notifier(struct notifier_block *nb,
				     unsigned long action, void *data)
{
	struct watchdog_device *wdd = container_of(nb, struct watchdog_device,
						   restart_nb);

	int ret;

	ret = wdd->ops->restart(wdd, action, data);
	if (ret)
		return NOTIFY_BAD;

	return NOTIFY_DONE;
}

/**
 * watchdog_set_restart_priority - Change priority of restart handler
 * @wdd: watchdog device
 * @priority: priority of the restart handler, should follow these guidelines:
 *   0:   use watchdog's restart function as last resort, has limited restart
 *        capabilies
 *   128: default restart handler, use if no other handler is expected to be
 *        available and/or if restart is sufficient to restart the entire system
 *   255: preempt all other handlers
 *
 * If a wdd->ops->restart function is provided when watchdog_register_device is
 * called, it will be registered as a restart handler with the priority given
 * here.
 */
void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority)
{
	wdd->restart_nb.priority = priority;
}
EXPORT_SYMBOL_GPL(watchdog_set_restart_priority);

static int __watchdog_register_device(struct watchdog_device *wdd)
{
	int ret, id = -1;

	if (wdd == NULL || wdd->info == NULL || wdd->ops == NULL)
		return -EINVAL;

	/* Mandatory operations need to be supported */
	if (!wdd->ops->start || (!wdd->ops->stop && !wdd->max_hw_heartbeat_ms))
		return -EINVAL;

	watchdog_check_min_max_timeout(wdd);

	/*
	 * 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!
	 */

	/* Use alias for watchdog id if possible */
	if (wdd->parent) {
		ret = of_alias_get_id(wdd->parent->of_node, "watchdog");
		if (ret >= 0)
			id = ida_simple_get(&watchdog_ida, ret,
					    ret + 1, GFP_KERNEL);
	}

	if (id < 0)
		id = ida_simple_get(&watchdog_ida, 0, MAX_DOGS, GFP_KERNEL);

	if (id < 0)
		return id;
	wdd->id = id;

	ret = watchdog_dev_register(wdd);
	if (ret) {
		ida_simple_remove(&watchdog_ida, id);
		if (!(id == 0 && ret == -EBUSY))
			return ret;

		/* Retry in case a legacy watchdog module exists */
		id = ida_simple_get(&watchdog_ida, 1, MAX_DOGS, GFP_KERNEL);
		if (id < 0)
			return id;
		wdd->id = id;

		ret = watchdog_dev_register(wdd);
		if (ret) {
			ida_simple_remove(&watchdog_ida, id);
			return ret;
		}
	}

	if (test_bit(WDOG_STOP_ON_REBOOT, &wdd->status)) {
		wdd->reboot_nb.notifier_call = watchdog_reboot_notifier;

		ret = register_reboot_notifier(&wdd->reboot_nb);
		if (ret) {
			pr_err("watchdog%d: Cannot register reboot notifier (%d)\n",
			       wdd->id, ret);
			watchdog_dev_unregister(wdd);
			ida_simple_remove(&watchdog_ida, wdd->id);
			return ret;
		}
	}

	if (wdd->ops->restart) {
		wdd->restart_nb.notifier_call = watchdog_restart_notifier;

		ret = register_restart_handler(&wdd->restart_nb);
		if (ret)
			pr_warn("watchog%d: Cannot register restart handler (%d)\n",
				wdd->id, ret);
	}

	return 0;
}

/**
 * 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;

	mutex_lock(&wtd_deferred_reg_mutex);
	if (wtd_deferred_reg_done)
		ret = __watchdog_register_device(wdd);
	else
		ret = watchdog_deferred_registration_add(wdd);
	mutex_unlock(&wtd_deferred_reg_mutex);
	return ret;
}
EXPORT_SYMBOL_GPL(watchdog_register_device);

static void __watchdog_unregister_device(struct watchdog_device *wdd)
{
	if (wdd == NULL)
		return;

	if (wdd->ops->restart)
		unregister_restart_handler(&wdd->restart_nb);

	if (test_bit(WDOG_STOP_ON_REBOOT, &wdd->status))
		unregister_reboot_notifier(&wdd->reboot_nb);

	watchdog_dev_unregister(wdd);
	ida_simple_remove(&watchdog_ida, wdd->id);
}

/**
 * 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)
{
	mutex_lock(&wtd_deferred_reg_mutex);
	if (wtd_deferred_reg_done)
		__watchdog_unregister_device(wdd);
	else
		watchdog_deferred_registration_del(wdd);
	mutex_unlock(&wtd_deferred_reg_mutex);
}

EXPORT_SYMBOL_GPL(watchdog_unregister_device);

static int __init watchdog_deferred_registration(void)
{
	mutex_lock(&wtd_deferred_reg_mutex);
	wtd_deferred_reg_done = true;
	while (!list_empty(&wtd_deferred_reg_list)) {
		struct watchdog_device *wdd;

		wdd = list_first_entry(&wtd_deferred_reg_list,
				       struct watchdog_device, deferred);
		list_del(&wdd->deferred);
		__watchdog_register_device(wdd);
	}
	mutex_unlock(&wtd_deferred_reg_mutex);
	return 0;
}

static int __init watchdog_init(void)
{
	int err;

	err = watchdog_dev_init();
	if (err < 0)
		return err;

	watchdog_deferred_registration();
	return 0;
}

static void __exit watchdog_exit(void)
{
	watchdog_dev_exit();
	ida_destroy(&watchdog_ida);
}

subsys_initcall_sync(watchdog_init);
module_exit(watchdog_exit);

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");
Commit	Line	Data
43316044 WVS	1	/*
	2	* watchdog_core.c
	3	*
	4	* (c) Copyright 2008-2011 Alan Cox <alan@lxorguk.ukuu.org.uk>,
	5	* All Rights Reserved.
	6	*
	7	* (c) Copyright 2008-2011 Wim Van Sebroeck <wim@iguana.be>.
	8	*
	9	* This source code is part of the generic code that can be used
	10	* by all the watchdog timer drivers.
	11	*
	12	* Based on source code of the following authors:
	13	* Matt Domsch <Matt_Domsch@dell.com>,
	14	* Rob Radez <rob@osinvestor.com>,
	15	* Rusty Lynch <rusty@linux.co.intel.com>
	16	* Satyam Sharma <satyam@infradead.org>
	17	* Randy Dunlap <randy.dunlap@oracle.com>
	18	*
	19	* This program is free software; you can redistribute it and/or
	20	* modify it under the terms of the GNU General Public License
	21	* as published by the Free Software Foundation; either version
	22	* 2 of the License, or (at your option) any later version.
	23	*
	24	* Neither Alan Cox, CymruNet Ltd., Wim Van Sebroeck nor Iguana vzw.
	25	* admit liability nor provide warranty for any of this software.
	26	* This material is provided "AS-IS" and at no charge.
	27	*/
	28
	29	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	30
	31	#include <linux/module.h> /* For EXPORT_SYMBOL/module stuff/... */
	32	#include <linux/types.h> /* For standard types */
	33	#include <linux/errno.h> /* For the -ENODEV/... values */
	34	#include <linux/kernel.h> /* For printk/panic/... */
2165bf52	35	#include <linux/reboot.h> /* For restart handler */
43316044 WVS	36	#include <linux/watchdog.h> /* For watchdog specific items */
43316044 WVS	37	#include <linux/init.h> /* For __init/__exit/... */
45f5fed3	38	#include <linux/idr.h> /* For ida_* macros */
d6b469d9	39	#include <linux/err.h> /* For IS_ERR macros */
3048253e	40	#include <linux/of.h> /* For of_get_timeout_sec */
43316044	41
6cfb5aa8	42	#include "watchdog_core.h" /* For watchdog_dev_register/... */
43316044	43
45f5fed3 AC	44	static DEFINE_IDA(watchdog_ida);
45f5fed3 AC	45
ef90174f JBT	46	/*
	47	* Deferred Registration infrastructure.
	48	*
	49	* Sometimes watchdog drivers needs to be loaded as soon as possible,
	50	* for example when it's impossible to disable it. To do so,
	51	* raising the initcall level of the watchdog driver is a solution.
	52	* But in such case, the miscdev is maybe not ready (subsys_initcall), and
	53	* watchdog_core need miscdev to register the watchdog as a char device.
	54	*
	55	* The deferred registration infrastructure offer a way for the watchdog
	56	* subsystem to register a watchdog properly, even before miscdev is ready.
	57	*/
	58
	59	static DEFINE_MUTEX(wtd_deferred_reg_mutex);
	60	static LIST_HEAD(wtd_deferred_reg_list);
	61	static bool wtd_deferred_reg_done;
	62
	63	static int watchdog_deferred_registration_add(struct watchdog_device *wdd)
	64	{
	65	list_add_tail(&wdd->deferred,
	66	&wtd_deferred_reg_list);
	67	return 0;
	68	}
	69
	70	static void watchdog_deferred_registration_del(struct watchdog_device *wdd)
	71	{
	72	struct list_head p, n;
	73	struct watchdog_device *wdd_tmp;
	74
	75	list_for_each_safe(p, n, &wtd_deferred_reg_list) {
	76	wdd_tmp = list_entry(p, struct watchdog_device,
	77	deferred);
	78	if (wdd_tmp == wdd) {
	79	list_del(&wdd_tmp->deferred);
	80	break;
	81	}
	82	}
	83	}
	84
3048253e FP	85	static void watchdog_check_min_max_timeout(struct watchdog_device *wdd)
	86	{
	87	/*
	88	* Check that we have valid min and max timeout values, if
	89	* not reset them both to 0 (=not used or unknown)
	90	*/
	91	if (wdd->min_timeout > wdd->max_timeout) {
	92	pr_info("Invalid min and max timeout values, resetting to 0!\n");
	93	wdd->min_timeout = 0;
	94	wdd->max_timeout = 0;
	95	}
	96	}
	97
	98	/**
	99	* watchdog_init_timeout() - initialize the timeout field
	100	* @timeout_parm: timeout module parameter
	101	* @dev: Device that stores the timeout-sec property
	102	*
	103	* Initialize the timeout field of the watchdog_device struct with either the
	104	* timeout module parameter (if it is valid value) or the timeout-sec property
	105	* (only if it is a valid value and the timeout_parm is out of bounds).
	106	* If none of them are valid then we keep the old value (which should normally
	107	* be the default timeout value.
	108	*
	109	* A zero is returned on success and -EINVAL for failure.
	110	*/
	111	int watchdog_init_timeout(struct watchdog_device *wdd,
	112	unsigned int timeout_parm, struct device *dev)
	113	{
	114	unsigned int t = 0;
	115	int ret = 0;
	116
	117	watchdog_check_min_max_timeout(wdd);
	118
6ffcff93	119	/* try to get the timeout module parameter first */
2c34d599	120	if (!watchdog_timeout_invalid(wdd, timeout_parm) && timeout_parm) {
3048253e FP	121	wdd->timeout = timeout_parm;
	122	return ret;
	123	}
	124	if (timeout_parm)
	125	ret = -EINVAL;
	126
	127	/* try to get the timeout_sec property */
	128	if (dev == NULL \|\| dev->of_node == NULL)
	129	return ret;
	130	of_property_read_u32(dev->of_node, "timeout-sec", &t);
2c34d599	131	if (!watchdog_timeout_invalid(wdd, t) && t)
3048253e FP	132	wdd->timeout = t;
	133	else
	134	ret = -EINVAL;
	135
	136	return ret;
	137	}
	138	EXPORT_SYMBOL_GPL(watchdog_init_timeout);
	139
e1313196 DR	140	static int watchdog_reboot_notifier(struct notifier_block *nb,
	141	unsigned long code, void *data)
	142	{
	143	struct watchdog_device *wdd = container_of(nb, struct watchdog_device,
	144	reboot_nb);
	145
	146	if (code == SYS_DOWN \|\| code == SYS_HALT) {
	147	if (watchdog_active(wdd)) {
	148	int ret;
	149
	150	ret = wdd->ops->stop(wdd);
	151	if (ret)
	152	return NOTIFY_BAD;
	153	}
	154	}
	155
	156	return NOTIFY_DONE;
	157	}
	158
2165bf52 DR	159	static int watchdog_restart_notifier(struct notifier_block *nb,
	160	unsigned long action, void *data)
	161	{
	162	struct watchdog_device *wdd = container_of(nb, struct watchdog_device,
	163	restart_nb);
	164
	165	int ret;
	166
4d8b229d	167	ret = wdd->ops->restart(wdd, action, data);
2165bf52 DR	168	if (ret)
	169	return NOTIFY_BAD;
	170
	171	return NOTIFY_DONE;
	172	}
	173
	174	/**
	175	* watchdog_set_restart_priority - Change priority of restart handler
	176	* @wdd: watchdog device
	177	* @priority: priority of the restart handler, should follow these guidelines:
	178	* 0: use watchdog's restart function as last resort, has limited restart
	179	* capabilies
	180	* 128: default restart handler, use if no other handler is expected to be
	181	* available and/or if restart is sufficient to restart the entire system
	182	* 255: preempt all other handlers
	183	*
	184	* If a wdd->ops->restart function is provided when watchdog_register_device is
	185	* called, it will be registered as a restart handler with the priority given
	186	* here.
	187	*/
	188	void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority)
	189	{
	190	wdd->restart_nb.priority = priority;
	191	}
	192	EXPORT_SYMBOL_GPL(watchdog_set_restart_priority);
	193
ef90174f	194	static int __watchdog_register_device(struct watchdog_device *wdd)
43316044	195	{
32ecc639	196	int ret, id = -1;
43316044 WVS	197
	198	if (wdd == NULL \|\| wdd->info == NULL \|\| wdd->ops == NULL)
	199	return -EINVAL;
	200
	201	/* Mandatory operations need to be supported */
d0684c8a	202	if (!wdd->ops->start \|\| (!wdd->ops->stop && !wdd->max_hw_heartbeat_ms))
43316044 WVS	203	return -EINVAL;
43316044 WVS	204
3048253e	205	watchdog_check_min_max_timeout(wdd);
3f43f68e	206
43316044 WVS	207	/*
	208	* Note: now that all watchdog_device data has been verified, we
	209	* will not check this anymore in other functions. If data gets
	210	* corrupted in a later stage then we expect a kernel panic!
	211	*/
	212
9dd4e173 JC	213	/* Use alias for watchdog id if possible */
	214	if (wdd->parent) {
	215	ret = of_alias_get_id(wdd->parent->of_node, "watchdog");
	216	if (ret >= 0)
	217	id = ida_simple_get(&watchdog_ida, ret,
	218	ret + 1, GFP_KERNEL);
	219	}
	220
	221	if (id < 0)
	222	id = ida_simple_get(&watchdog_ida, 0, MAX_DOGS, GFP_KERNEL);
	223
45f5fed3 AC	224	if (id < 0)
	225	return id;
	226	wdd->id = id;
	227
43316044 WVS	228	ret = watchdog_dev_register(wdd);
43316044 WVS	229	if (ret) {
45f5fed3 AC	230	ida_simple_remove(&watchdog_ida, id);
	231	if (!(id == 0 && ret == -EBUSY))
	232	return ret;
	233
	234	/* Retry in case a legacy watchdog module exists */
	235	id = ida_simple_get(&watchdog_ida, 1, MAX_DOGS, GFP_KERNEL);
	236	if (id < 0)
	237	return id;
	238	wdd->id = id;
	239
	240	ret = watchdog_dev_register(wdd);
	241	if (ret) {
	242	ida_simple_remove(&watchdog_ida, id);
	243	return ret;
	244	}
43316044 WVS	245	}
43316044 WVS	246
e1313196 DR	247	if (test_bit(WDOG_STOP_ON_REBOOT, &wdd->status)) {
	248	wdd->reboot_nb.notifier_call = watchdog_reboot_notifier;
	249
	250	ret = register_reboot_notifier(&wdd->reboot_nb);
	251	if (ret) {
0254e953 GR	252	pr_err("watchdog%d: Cannot register reboot notifier (%d)\n",
0254e953 GR	253	wdd->id, ret);
e1313196	254	watchdog_dev_unregister(wdd);
e1313196	255	ida_simple_remove(&watchdog_ida, wdd->id);
e1313196 DR	256	return ret;
	257	}
	258	}
	259
2165bf52 DR	260	if (wdd->ops->restart) {
	261	wdd->restart_nb.notifier_call = watchdog_restart_notifier;
	262
	263	ret = register_restart_handler(&wdd->restart_nb);
	264	if (ret)
0254e953 GR	265	pr_warn("watchog%d: Cannot register restart handler (%d)\n",
0254e953 GR	266	wdd->id, ret);
2165bf52 DR	267	}
2165bf52 DR	268
43316044 WVS	269	return 0;
43316044 WVS	270	}
43316044 WVS	271
43316044 WVS	272	/**
ef90174f JBT	273	* watchdog_register_device() - register a watchdog device
ef90174f JBT	274	* @wdd: watchdog device
43316044	275	*
ef90174f JBT	276	* Register a watchdog device with the kernel so that the
	277	* watchdog timer can be accessed from userspace.
	278	*
	279	* A zero is returned on success and a negative errno code for
	280	* failure.
43316044	281	*/
ef90174f JBT	282
	283	int watchdog_register_device(struct watchdog_device *wdd)
	284	{
	285	int ret;
	286
	287	mutex_lock(&wtd_deferred_reg_mutex);
	288	if (wtd_deferred_reg_done)
	289	ret = __watchdog_register_device(wdd);
	290	else
	291	ret = watchdog_deferred_registration_add(wdd);
	292	mutex_unlock(&wtd_deferred_reg_mutex);
	293	return ret;
	294	}
	295	EXPORT_SYMBOL_GPL(watchdog_register_device);
	296
	297	static void __watchdog_unregister_device(struct watchdog_device *wdd)
43316044	298	{
43316044 WVS	299	if (wdd == NULL)
	300	return;
	301
2165bf52 DR	302	if (wdd->ops->restart)
	303	unregister_restart_handler(&wdd->restart_nb);
	304
e1313196 DR	305	if (test_bit(WDOG_STOP_ON_REBOOT, &wdd->status))
	306	unregister_reboot_notifier(&wdd->reboot_nb);
	307
32ecc639	308	watchdog_dev_unregister(wdd);
45f5fed3	309	ida_simple_remove(&watchdog_ida, wdd->id);
43316044	310	}
ef90174f JBT	311
	312	/**
	313	* watchdog_unregister_device() - unregister a watchdog device
	314	* @wdd: watchdog device to unregister
	315	*
	316	* Unregister a watchdog device that was previously successfully
	317	* registered with watchdog_register_device().
	318	*/
	319
	320	void watchdog_unregister_device(struct watchdog_device *wdd)
	321	{
	322	mutex_lock(&wtd_deferred_reg_mutex);
	323	if (wtd_deferred_reg_done)
	324	__watchdog_unregister_device(wdd);
	325	else
	326	watchdog_deferred_registration_del(wdd);
	327	mutex_unlock(&wtd_deferred_reg_mutex);
	328	}
	329
43316044 WVS	330	EXPORT_SYMBOL_GPL(watchdog_unregister_device);
43316044 WVS	331
ef90174f JBT	332	static int __init watchdog_deferred_registration(void)
	333	{
	334	mutex_lock(&wtd_deferred_reg_mutex);
	335	wtd_deferred_reg_done = true;
	336	while (!list_empty(&wtd_deferred_reg_list)) {
	337	struct watchdog_device *wdd;
	338
	339	wdd = list_first_entry(&wtd_deferred_reg_list,
	340	struct watchdog_device, deferred);
	341	list_del(&wdd->deferred);
	342	__watchdog_register_device(wdd);
	343	}
	344	mutex_unlock(&wtd_deferred_reg_mutex);
	345	return 0;
	346	}
	347
45f5fed3 AC	348	static int __init watchdog_init(void)
45f5fed3 AC	349	{
32ecc639 GR	350	int err;
	351
	352	err = watchdog_dev_init();
	353	if (err < 0)
	354	return err;
d6b469d9	355
ef90174f	356	watchdog_deferred_registration();
d6b469d9	357	return 0;
45f5fed3 AC	358	}
	359
	360	static void __exit watchdog_exit(void)
	361	{
	362	watchdog_dev_exit();
	363	ida_destroy(&watchdog_ida);
	364	}
	365
ef90174f	366	subsys_initcall_sync(watchdog_init);
45f5fed3 AC	367	module_exit(watchdog_exit);
45f5fed3 AC	368
43316044 WVS	369	MODULE_AUTHOR("Alan Cox <alan@lxorguk.ukuu.org.uk>");
	370	MODULE_AUTHOR("Wim Van Sebroeck <wim@iguana.be>");
	371	MODULE_DESCRIPTION("WatchDog Timer Driver Core");
	372	MODULE_LICENSE("GPL");