kernel/power/wakeup_reason.c

   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 irqcount;
  34 static bool suspend_abort;
  35 static char abort_reason[MAX_SUSPEND_ABORT_LEN];
  36 static struct kobject *wakeup_reason;
  37 static spinlock_t resume_reason_lock;
  38
  39 static ssize_t last_resume_reason_show(struct kobject *kobj, struct kobj_attribute *attr,
  40                 char *buf)
  41 {
  42         int irq_no, buf_offset = 0;
  43         struct irq_desc *desc;
  44         spin_lock(&resume_reason_lock);
  45         if (suspend_abort) {
  46                 buf_offset = sprintf(buf, "Abort: %s", abort_reason);
  47         } else {
  48                 for (irq_no = 0; irq_no < irqcount; irq_no++) {
  49                         desc = irq_to_desc(irq_list[irq_no]);
  50                         if (desc && desc->action && desc->action->name)
  51                                 buf_offset += sprintf(buf + buf_offset, "%d %s\n",
  52                                                 irq_list[irq_no], desc->action->name);
  53                         else
  54                                 buf_offset += sprintf(buf + buf_offset, "%d\n",
  55                                                 irq_list[irq_no]);
  56                 }
  57         }
  58         spin_unlock(&resume_reason_lock);
  59         return buf_offset;
  60 }
  61
  62 static struct kobj_attribute resume_reason = __ATTR_RO(last_resume_reason);
  63
  64 static struct attribute *attrs[] = {
  65         &resume_reason.attr,
  66         NULL,
  67 };
  68 static struct attribute_group attr_group = {
  69         .attrs = attrs,
  70 };
  71
  72 /*
  73  * logs all the wake up reasons to the kernel
  74  * stores the irqs to expose them to the userspace via sysfs
  75  */
  76 void log_wakeup_reason(int irq)
  77 {
  78         struct irq_desc *desc;
  79         desc = irq_to_desc(irq);
  80         if (desc && desc->action && desc->action->name)
  81                 printk(KERN_INFO "Resume caused by IRQ %d, %s\n", irq,
  82                                 desc->action->name);
  83         else
  84                 printk(KERN_INFO "Resume caused by IRQ %d\n", irq);
  85
  86         spin_lock(&resume_reason_lock);
  87         if (irqcount == MAX_WAKEUP_REASON_IRQS) {
  88                 spin_unlock(&resume_reason_lock);
  89                 printk(KERN_WARNING "Resume caused by more than %d IRQs\n",
  90                                 MAX_WAKEUP_REASON_IRQS);
  91                 return;
  92         }
  93
  94         irq_list[irqcount++] = irq;
  95         spin_unlock(&resume_reason_lock);
  96 }
  97
  98 void log_suspend_abort_reason(const char *fmt, ...)
  99 {
 100         va_list args;
 101
 102         spin_lock(&resume_reason_lock);
 103
 104         //Suspend abort reason has already been logged.
 105         if (suspend_abort) {
 106                 spin_unlock(&resume_reason_lock);
 107                 return;
 108         }
 109
 110         suspend_abort = true;
 111         va_start(args, fmt);
 112         snprintf(abort_reason, MAX_SUSPEND_ABORT_LEN, fmt, args);
 113         va_end(args);
 114         spin_unlock(&resume_reason_lock);
 115 }
 116
 117 /* Detects a suspend and clears all the previous wake up reasons*/
 118 static int wakeup_reason_pm_event(struct notifier_block *notifier,
 119                 unsigned long pm_event, void *unused)
 120 {
 121         switch (pm_event) {
 122         case PM_SUSPEND_PREPARE:
 123                 spin_lock(&resume_reason_lock);
 124                 irqcount = 0;
 125                 suspend_abort = false;
 126                 spin_unlock(&resume_reason_lock);
 127                 break;
 128         default:
 129                 break;
 130         }
 131         return NOTIFY_DONE;
 132 }
 133
 134 static struct notifier_block wakeup_reason_pm_notifier_block = {
 135         .notifier_call = wakeup_reason_pm_event,
 136 };
 137
 138 /* Initializes the sysfs parameter
 139  * registers the pm_event notifier
 140  */
 141 int __init wakeup_reason_init(void)
 142 {
 143         int retval;
 144         spin_lock_init(&resume_reason_lock);
 145         retval = register_pm_notifier(&wakeup_reason_pm_notifier_block);
 146         if (retval)
 147                 printk(KERN_WARNING "[%s] failed to register PM notifier %d\n",
 148                                 __func__, retval);
 149
 150         wakeup_reason = kobject_create_and_add("wakeup_reasons", kernel_kobj);
 151         if (!wakeup_reason) {
 152                 printk(KERN_WARNING "[%s] failed to create a sysfs kobject\n",
 153                                 __func__);
 154                 return 1;
 155         }
 156         retval = sysfs_create_group(wakeup_reason, &attr_group);
 157         if (retval) {
 158                 kobject_put(wakeup_reason);
 159                 printk(KERN_WARNING "[%s] failed to create a sysfs group %d\n",
 160                                 __func__, retval);
 161         }
 162         return 0;
 163 }
 164
 165 late_initcall(wakeup_reason_init);