kernel/irq/pm.c

   1 /*
   2  * linux/kernel/irq/pm.c
   3  *
   4  * Copyright (C) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
   5  *
   6  * This file contains power management functions related to interrupts.
   7  */
   8
   9 #include <linux/irq.h>
  10 #include <linux/module.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/syscore_ops.h>
  13
  14 #include "internals.h"
  15
  16 /**
  17  * suspend_device_irqs - disable all currently enabled interrupt lines
  18  *
  19  * During system-wide suspend or hibernation device drivers need to be prevented
  20  * from receiving interrupts and this function is provided for this purpose.
  21  * It marks all interrupt lines in use, except for the timer ones, as disabled
  22  * and sets the IRQS_SUSPENDED flag for each of them.
  23  */
  24 void suspend_device_irqs(void)
  25 {
  26         struct irq_desc *desc;
  27         int irq;
  28
  29         for_each_irq_desc(irq, desc) {
  30                 unsigned long flags;
  31
  32                 raw_spin_lock_irqsave(&desc->lock, flags);
  33                 __disable_irq(desc, irq, true);
  34                 raw_spin_unlock_irqrestore(&desc->lock, flags);
  35         }
  36
  37         for_each_irq_desc(irq, desc)
  38                 if (desc->istate & IRQS_SUSPENDED)
  39                         synchronize_irq(irq);
  40 }
  41 EXPORT_SYMBOL_GPL(suspend_device_irqs);
  42
  43 static void resume_irqs(bool want_early)
  44 {
  45         struct irq_desc *desc;
  46         int irq;
  47
  48         for_each_irq_desc(irq, desc) {
  49                 unsigned long flags;
  50                 bool is_early = desc->action &&
  51                         desc->action->flags & IRQF_EARLY_RESUME;
  52
  53                 if (is_early != want_early)
  54                         continue;
  55
  56                 raw_spin_lock_irqsave(&desc->lock, flags);
  57                 __enable_irq(desc, irq, true);
  58                 raw_spin_unlock_irqrestore(&desc->lock, flags);
  59         }
  60 }
  61
  62 /**
  63  * irq_pm_syscore_ops - enable interrupt lines early
  64  *
  65  * Enable all interrupt lines with %IRQF_EARLY_RESUME set.
  66  */
  67 static void irq_pm_syscore_resume(void)
  68 {
  69         resume_irqs(true);
  70 }
  71
  72 static struct syscore_ops irq_pm_syscore_ops = {
  73         .resume         = irq_pm_syscore_resume,
  74 };
  75
  76 static int __init irq_pm_init_ops(void)
  77 {
  78         register_syscore_ops(&irq_pm_syscore_ops);
  79         return 0;
  80 }
  81
  82 device_initcall(irq_pm_init_ops);
  83
  84 /**
  85  * resume_device_irqs - enable interrupt lines disabled by suspend_device_irqs()
  86  *
  87  * Enable all non-%IRQF_EARLY_RESUME interrupt lines previously
  88  * disabled by suspend_device_irqs() that have the IRQS_SUSPENDED flag
  89  * set as well as those with %IRQF_FORCE_RESUME.
  90  */
  91 void resume_device_irqs(void)
  92 {
  93         resume_irqs(false);
  94 }
  95 EXPORT_SYMBOL_GPL(resume_device_irqs);
  96
  97 /**
  98  * check_wakeup_irqs - check if any wake-up interrupts are pending
  99  */
 100 int check_wakeup_irqs(void)
 101 {
 102         struct irq_desc *desc;
 103         int irq;
 104
 105         for_each_irq_desc(irq, desc) {
 106                 if (irqd_is_wakeup_set(&desc->irq_data)) {
 107                         if (desc->istate & IRQS_PENDING)
 108                                 return -EBUSY;
 109                         continue;
 110                 }
 111                 /*
 112                  * Check the non wakeup interrupts whether they need
 113                  * to be masked before finally going into suspend
 114                  * state. That's for hardware which has no wakeup
 115                  * source configuration facility. The chip
 116                  * implementation indicates that with
 117                  * IRQCHIP_MASK_ON_SUSPEND.
 118                  */
 119                 if (desc->istate & IRQS_SUSPENDED &&
 120                     irq_desc_get_chip(desc)->flags & IRQCHIP_MASK_ON_SUSPEND)
 121                         mask_irq(desc);
 122         }
 123
 124         return 0;
 125 }