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 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 < irq_count; 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(last_resume_reason, 0666,
59 static struct attribute *attrs[] = {
63 static struct attribute_group attr_group = {
68 * logs all the wake up reasons to the kernel
69 * stores the irqs to expose them to the userspace via sysfs
71 void log_wakeup_reason(int irq)
73 struct irq_desc *desc;
74 desc = irq_to_desc(irq);
75 if (desc && desc->action && desc->action->name)
76 printk(KERN_INFO "Resume caused by IRQ %d, %s\n", irq,
79 printk(KERN_INFO "Resume caused by IRQ %d\n", irq);
81 spin_lock(&resume_reason_lock);
82 if (irq_count == MAX_WAKEUP_REASON_IRQS) {
83 spin_unlock(&resume_reason_lock);
84 printk(KERN_WARNING "Resume caused by more than %d IRQs\n",
85 MAX_WAKEUP_REASON_IRQS);
89 irq_list[irq_count++] = irq;
90 spin_unlock(&resume_reason_lock);
93 /* Detects a suspend and clears all the previous wake up reasons*/
94 static int wakeup_reason_pm_event(struct notifier_block *notifier,
95 unsigned long pm_event, void *unused)
98 case PM_SUSPEND_PREPARE:
99 spin_lock(&resume_reason_lock);
101 spin_unlock(&resume_reason_lock);
109 static struct notifier_block wakeup_reason_pm_notifier_block = {
110 .notifier_call = wakeup_reason_pm_event,
113 /* Initializes the sysfs parameter
114 * registers the pm_event notifier
116 int __init wakeup_reason_init(void)
119 spin_lock_init(&resume_reason_lock);
120 retval = register_pm_notifier(&wakeup_reason_pm_notifier_block);
122 printk(KERN_WARNING "[%s] failed to register PM notifier %d\n",
125 wakeup_reason = kobject_create_and_add("wakeup_reasons", kernel_kobj);
126 if (!wakeup_reason) {
127 printk(KERN_WARNING "[%s] failed to create a sysfs kobject\n",
131 retval = sysfs_create_group(wakeup_reason, &attr_group);
133 kobject_put(wakeup_reason);
134 printk(KERN_WARNING "[%s] failed to create a sysfs group %d\n",
140 late_initcall(wakeup_reason_init);