Ruchi Kandoi | 6acefbe | 2014-02-19 15:30:47 -0800 | [diff] [blame] | 1 | /* |
| 2 | * kernel/power/wakeup_reason.c |
| 3 | * |
| 4 | * Logs the reasons which caused the kernel to resume from |
| 5 | * the suspend mode. |
| 6 | * |
| 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. |
| 11 | * |
| 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. |
| 16 | */ |
| 17 | |
| 18 | #include <linux/wakeup_reason.h> |
| 19 | #include <linux/kernel.h> |
| 20 | #include <linux/irq.h> |
| 21 | #include <linux/interrupt.h> |
| 22 | #include <linux/io.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> |
| 29 | |
| 30 | |
| 31 | #define MAX_WAKEUP_REASON_IRQS 32 |
| 32 | static int irq_list[MAX_WAKEUP_REASON_IRQS]; |
| 33 | static int irq_count; |
| 34 | static struct kobject *wakeup_reason; |
| 35 | static spinlock_t resume_reason_lock; |
| 36 | |
| 37 | static ssize_t reason_show(struct kobject *kobj, struct kobj_attribute *attr, |
Ruchi Kandoi | 1135122 | 2014-02-20 19:47:38 -0800 | [diff] [blame^] | 38 | char *buf) |
Ruchi Kandoi | 6acefbe | 2014-02-19 15:30:47 -0800 | [diff] [blame] | 39 | { |
| 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); |
| 48 | else |
| 49 | buf_offset += sprintf(buf + buf_offset, "%d\n", |
| 50 | irq_list[irq_no]); |
| 51 | } |
| 52 | spin_unlock(&resume_reason_lock); |
| 53 | return buf_offset; |
| 54 | } |
| 55 | |
| 56 | static struct kobj_attribute resume_reason = __ATTR(last_resume_reason, 0666, |
| 57 | reason_show, NULL); |
| 58 | |
| 59 | static struct attribute *attrs[] = { |
| 60 | &resume_reason.attr, |
| 61 | NULL, |
| 62 | }; |
| 63 | static struct attribute_group attr_group = { |
| 64 | .attrs = attrs, |
| 65 | }; |
| 66 | |
| 67 | /* |
| 68 | * logs all the wake up reasons to the kernel |
| 69 | * stores the irqs to expose them to the userspace via sysfs |
| 70 | */ |
| 71 | void log_wakeup_reason(int irq) |
| 72 | { |
| 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, |
| 77 | desc->action->name); |
| 78 | else |
| 79 | printk(KERN_INFO "Resume caused by IRQ %d\n", irq); |
| 80 | |
| 81 | spin_lock(&resume_reason_lock); |
| 82 | irq_list[irq_count++] = irq; |
| 83 | spin_unlock(&resume_reason_lock); |
| 84 | } |
| 85 | |
| 86 | /* Detects a suspend and clears all the previous wake up reasons*/ |
| 87 | static int wakeup_reason_pm_event(struct notifier_block *notifier, |
| 88 | unsigned long pm_event, void *unused) |
| 89 | { |
| 90 | switch (pm_event) { |
| 91 | case PM_SUSPEND_PREPARE: |
| 92 | spin_lock(&resume_reason_lock); |
| 93 | irq_count = 0; |
| 94 | spin_unlock(&resume_reason_lock); |
| 95 | break; |
| 96 | default: |
| 97 | break; |
| 98 | } |
| 99 | return NOTIFY_DONE; |
| 100 | } |
| 101 | |
| 102 | static struct notifier_block wakeup_reason_pm_notifier_block = { |
| 103 | .notifier_call = wakeup_reason_pm_event, |
| 104 | }; |
| 105 | |
| 106 | /* Initializes the sysfs parameter |
| 107 | * registers the pm_event notifier |
| 108 | */ |
Ruchi Kandoi | 1135122 | 2014-02-20 19:47:38 -0800 | [diff] [blame^] | 109 | int __init wakeup_reason_init(void) |
Ruchi Kandoi | 6acefbe | 2014-02-19 15:30:47 -0800 | [diff] [blame] | 110 | { |
| 111 | int retval; |
| 112 | spin_lock_init(&resume_reason_lock); |
| 113 | retval = register_pm_notifier(&wakeup_reason_pm_notifier_block); |
| 114 | if (retval) |
| 115 | printk(KERN_WARNING "[%s] failed to register PM notifier %d\n", |
| 116 | __func__, retval); |
| 117 | |
| 118 | wakeup_reason = kobject_create_and_add("wakeup_reasons", kernel_kobj); |
| 119 | if (!wakeup_reason) { |
| 120 | printk(KERN_WARNING "[%s] failed to create a sysfs kobject\n", |
| 121 | __func__); |
Ruchi Kandoi | 1135122 | 2014-02-20 19:47:38 -0800 | [diff] [blame^] | 122 | return 1; |
Ruchi Kandoi | 6acefbe | 2014-02-19 15:30:47 -0800 | [diff] [blame] | 123 | } |
| 124 | retval = sysfs_create_group(wakeup_reason, &attr_group); |
| 125 | if (retval) { |
| 126 | kobject_put(wakeup_reason); |
| 127 | printk(KERN_WARNING "[%s] failed to create a sysfs group %d\n", |
| 128 | __func__, retval); |
| 129 | } |
Ruchi Kandoi | 1135122 | 2014-02-20 19:47:38 -0800 | [diff] [blame^] | 130 | return 0; |
Ruchi Kandoi | 6acefbe | 2014-02-19 15:30:47 -0800 | [diff] [blame] | 131 | } |
| 132 | |
| 133 | late_initcall(wakeup_reason_init); |