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/*
* kernel/power/wakeup_reason.c
*
* Logs the reasons which caused the kernel to resume from
* the suspend mode.
*
* Copyright (C) 2014 Google, Inc.
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* 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.
*/
#include <linux/wakeup_reason.h>
#include <linux/kernel.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kobject.h>
#include <linux/sysfs.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/notifier.h>
#include <linux/suspend.h>
#define MAX_WAKEUP_REASON_IRQS 32
static int irq_list[MAX_WAKEUP_REASON_IRQS];
static int irq_count;
static struct kobject *wakeup_reason;
static spinlock_t resume_reason_lock;
static ssize_t reason_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
int irq_no, buf_offset = 0;
struct irq_desc *desc;
spin_lock(&resume_reason_lock);
for (irq_no = 0; irq_no < irq_count; irq_no++) {
desc = irq_to_desc(irq_list[irq_no]);
if (desc && desc->action && desc->action->name)
buf_offset += sprintf(buf + buf_offset, "%d %s\n",
irq_list[irq_no], desc->action->name);
else
buf_offset += sprintf(buf + buf_offset, "%d\n",
irq_list[irq_no]);
}
spin_unlock(&resume_reason_lock);
return buf_offset;
}
static struct kobj_attribute resume_reason = __ATTR(last_resume_reason, 0666,
reason_show, NULL);
static struct attribute *attrs[] = {
&resume_reason.attr,
NULL,
};
static struct attribute_group attr_group = {
.attrs = attrs,
};
/*
* logs all the wake up reasons to the kernel
* stores the irqs to expose them to the userspace via sysfs
*/
void log_wakeup_reason(int irq)
{
struct irq_desc *desc;
desc = irq_to_desc(irq);
if (desc && desc->action && desc->action->name)
printk(KERN_INFO "Resume caused by IRQ %d, %s\n", irq,
desc->action->name);
else
printk(KERN_INFO "Resume caused by IRQ %d\n", irq);
spin_lock(&resume_reason_lock);
irq_list[irq_count++] = irq;
spin_unlock(&resume_reason_lock);
}
/* Detects a suspend and clears all the previous wake up reasons*/
static int wakeup_reason_pm_event(struct notifier_block *notifier,
unsigned long pm_event, void *unused)
{
switch (pm_event) {
case PM_SUSPEND_PREPARE:
spin_lock(&resume_reason_lock);
irq_count = 0;
spin_unlock(&resume_reason_lock);
break;
default:
break;
}
return NOTIFY_DONE;
}
static struct notifier_block wakeup_reason_pm_notifier_block = {
.notifier_call = wakeup_reason_pm_event,
};
/* Initializes the sysfs parameter
* registers the pm_event notifier
*/
int __init wakeup_reason_init(void)
{
int retval;
spin_lock_init(&resume_reason_lock);
retval = register_pm_notifier(&wakeup_reason_pm_notifier_block);
if (retval)
printk(KERN_WARNING "[%s] failed to register PM notifier %d\n",
__func__, retval);
wakeup_reason = kobject_create_and_add("wakeup_reasons", kernel_kobj);
if (!wakeup_reason) {
printk(KERN_WARNING "[%s] failed to create a sysfs kobject\n",
__func__);
return 1;
}
retval = sysfs_create_group(wakeup_reason, &attr_group);
if (retval) {
kobject_put(wakeup_reason);
printk(KERN_WARNING "[%s] failed to create a sysfs group %d\n",
__func__, retval);
}
return 0;
}
late_initcall(wakeup_reason_init);
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