2 * kernel/power/wakeup_reason.c
4 * Logs the reasons which caused the kernel to resume from
7 * Copyright (C) 2014 Google, Inc.
8 * This software is licensed under the terms of the GNU General Public
9 * License version 2, as published by the Free Software Foundation, and
10 * may be copied, distributed, and modified under those terms.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
18 #include <linux/wakeup_reason.h>
19 #include <linux/kernel.h>
20 #include <linux/irq.h>
21 #include <linux/interrupt.h>
23 #include <linux/kobject.h>
24 #include <linux/sysfs.h>
25 #include <linux/init.h>
26 #include <linux/spinlock.h>
27 #include <linux/notifier.h>
28 #include <linux/suspend.h>
31 #define MAX_WAKEUP_REASON_IRQS 32
32 static int irq_list[MAX_WAKEUP_REASON_IRQS];
34 static struct kobject *wakeup_reason;
35 static spinlock_t resume_reason_lock;
37 static ssize_t last_resume_reason_show(struct kobject *kobj, struct kobj_attribute *attr,
40 int irq_no, buf_offset = 0;
41 struct irq_desc *desc;
42 spin_lock(&resume_reason_lock);
43 for (irq_no = 0; irq_no < irqcount; irq_no++) {
44 desc = irq_to_desc(irq_list[irq_no]);
45 if (desc && desc->action && desc->action->name)
46 buf_offset += sprintf(buf + buf_offset, "%d %s\n",
47 irq_list[irq_no], desc->action->name);
49 buf_offset += sprintf(buf + buf_offset, "%d\n",
52 spin_unlock(&resume_reason_lock);
56 static struct kobj_attribute resume_reason = __ATTR_RO(last_resume_reason);
58 static struct attribute *attrs[] = {
62 static struct attribute_group attr_group = {
67 * logs all the wake up reasons to the kernel
68 * stores the irqs to expose them to the userspace via sysfs
70 void log_wakeup_reason(int irq)
72 struct irq_desc *desc;
73 desc = irq_to_desc(irq);
74 if (desc && desc->action && desc->action->name)
75 printk(KERN_INFO "Resume caused by IRQ %d, %s\n", irq,
78 printk(KERN_INFO "Resume caused by IRQ %d\n", irq);
80 spin_lock(&resume_reason_lock);
81 if (irqcount == MAX_WAKEUP_REASON_IRQS) {
82 spin_unlock(&resume_reason_lock);
83 printk(KERN_WARNING "Resume caused by more than %d IRQs\n",
84 MAX_WAKEUP_REASON_IRQS);
88 irq_list[irqcount++] = irq;
89 spin_unlock(&resume_reason_lock);
92 /* Detects a suspend and clears all the previous wake up reasons*/
93 static int wakeup_reason_pm_event(struct notifier_block *notifier,
94 unsigned long pm_event, void *unused)
97 case PM_SUSPEND_PREPARE:
98 spin_lock(&resume_reason_lock);
100 spin_unlock(&resume_reason_lock);
108 static struct notifier_block wakeup_reason_pm_notifier_block = {
109 .notifier_call = wakeup_reason_pm_event,
112 /* Initializes the sysfs parameter
113 * registers the pm_event notifier
115 int __init wakeup_reason_init(void)
118 spin_lock_init(&resume_reason_lock);
119 retval = register_pm_notifier(&wakeup_reason_pm_notifier_block);
121 printk(KERN_WARNING "[%s] failed to register PM notifier %d\n",
124 wakeup_reason = kobject_create_and_add("wakeup_reasons", kernel_kobj);
125 if (!wakeup_reason) {
126 printk(KERN_WARNING "[%s] failed to create a sysfs kobject\n",
130 retval = sysfs_create_group(wakeup_reason, &attr_group);
132 kobject_put(wakeup_reason);
133 printk(KERN_WARNING "[%s] failed to create a sysfs group %d\n",
139 late_initcall(wakeup_reason_init);