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/* Copyright (c) 2011, Code Aurora Forum. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*
* Subsystem Notifier -- Provides notifications
* of subsys events.
*
* Use subsys_notif_register_notifier to register for notifications
* and subsys_notif_queue_notification to send notifications.
*
*/
#include <linux/notifier.h>
#include <linux/init.h>
#include <linux/debugfs.h>
#include <linux/module.h>
#include <linux/workqueue.h>
#include <linux/stringify.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <mach/subsystem_notif.h>
struct subsys_notif_info {
char name[50];
struct srcu_notifier_head subsys_notif_rcvr_list;
struct list_head list;
};
static LIST_HEAD(subsystem_list);
static DEFINE_MUTEX(notif_lock);
static DEFINE_MUTEX(notif_add_lock);
#if defined(SUBSYS_RESTART_DEBUG)
static void subsys_notif_reg_test_notifier(const char *);
#endif
static struct subsys_notif_info *_notif_find_subsys(const char *subsys_name)
{
struct subsys_notif_info *subsys;
mutex_lock(¬if_lock);
list_for_each_entry(subsys, &subsystem_list, list)
if (!strncmp(subsys->name, subsys_name,
ARRAY_SIZE(subsys->name))) {
mutex_unlock(¬if_lock);
return subsys;
}
mutex_unlock(¬if_lock);
return NULL;
}
void *subsys_notif_register_notifier(
const char *subsys_name, struct notifier_block *nb)
{
int ret;
struct subsys_notif_info *subsys = _notif_find_subsys(subsys_name);
if (!subsys) {
/* Possible first time reference to this subsystem. Add it. */
subsys = (struct subsys_notif_info *)
subsys_notif_add_subsys(subsys_name);
if (!subsys)
return ERR_PTR(-EINVAL);
}
ret = srcu_notifier_chain_register(
&subsys->subsys_notif_rcvr_list, nb);
if (ret < 0)
return ERR_PTR(ret);
return subsys;
}
EXPORT_SYMBOL(subsys_notif_register_notifier);
int subsys_notif_unregister_notifier(void *subsys_handle,
struct notifier_block *nb)
{
int ret;
struct subsys_notif_info *subsys =
(struct subsys_notif_info *)subsys_handle;
if (!subsys)
return -EINVAL;
ret = srcu_notifier_chain_unregister(
&subsys->subsys_notif_rcvr_list, nb);
return ret;
}
EXPORT_SYMBOL(subsys_notif_unregister_notifier);
void *subsys_notif_add_subsys(const char *subsys_name)
{
struct subsys_notif_info *subsys = NULL;
if (!subsys_name)
goto done;
mutex_lock(¬if_add_lock);
subsys = _notif_find_subsys(subsys_name);
if (subsys) {
mutex_unlock(¬if_add_lock);
goto done;
}
subsys = kmalloc(sizeof(struct subsys_notif_info), GFP_KERNEL);
if (!subsys) {
mutex_unlock(¬if_add_lock);
return ERR_PTR(-EINVAL);
}
strlcpy(subsys->name, subsys_name, ARRAY_SIZE(subsys->name));
srcu_init_notifier_head(&subsys->subsys_notif_rcvr_list);
INIT_LIST_HEAD(&subsys->list);
mutex_lock(¬if_lock);
list_add_tail(&subsys->list, &subsystem_list);
mutex_unlock(¬if_lock);
#if defined(SUBSYS_RESTART_DEBUG)
subsys_notif_reg_test_notifier(subsys->name);
#endif
mutex_unlock(¬if_add_lock);
done:
return subsys;
}
EXPORT_SYMBOL(subsys_notif_add_subsys);
int subsys_notif_queue_notification(void *subsys_handle,
enum subsys_notif_type notif_type)
{
int ret = 0;
struct subsys_notif_info *subsys =
(struct subsys_notif_info *) subsys_handle;
if (!subsys)
return -EINVAL;
if (notif_type < 0 || notif_type >= SUBSYS_NOTIF_TYPE_COUNT)
return -EINVAL;
ret = srcu_notifier_call_chain(
&subsys->subsys_notif_rcvr_list, notif_type,
(void *)subsys);
return ret;
}
EXPORT_SYMBOL(subsys_notif_queue_notification);
#if defined(SUBSYS_RESTART_DEBUG)
static const char *notif_to_string(enum subsys_notif_type notif_type)
{
switch (notif_type) {
case SUBSYS_BEFORE_SHUTDOWN:
return __stringify(SUBSYS_BEFORE_SHUTDOWN);
case SUBSYS_AFTER_SHUTDOWN:
return __stringify(SUBSYS_AFTER_SHUTDOWN);
case SUBSYS_BEFORE_POWERUP:
return __stringify(SUBSYS_BEFORE_POWERUP);
case SUBSYS_AFTER_POWERUP:
return __stringify(SUBSYS_AFTER_POWERUP);
default:
return "unknown";
}
}
static int subsys_notifier_test_call(struct notifier_block *this,
unsigned long code,
void *data)
{
switch (code) {
default:
printk(KERN_WARNING "%s: Notification %s from subsystem %p\n",
__func__, notif_to_string(code), data);
break;
}
return NOTIFY_DONE;
}
static struct notifier_block nb = {
.notifier_call = subsys_notifier_test_call,
};
static void subsys_notif_reg_test_notifier(const char *subsys_name)
{
void *handle = subsys_notif_register_notifier(subsys_name, &nb);
printk(KERN_WARNING "%s: Registered test notifier, handle=%p",
__func__, handle);
}
#endif
MODULE_DESCRIPTION("Subsystem Restart Notifier");
MODULE_VERSION("1.0");
MODULE_LICENSE("GPL v2");
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