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
  13 #include "internals.h"
  14
  15 /**
  16  * suspend_device_irqs - disable all currently enabled interrupt lines
  17  *
  18  * During system-wide suspend or hibernation device drivers need to be prevented
  19  * from receiving interrupts and this function is provided for this purpose.
  20  * It marks all interrupt lines in use, except for the timer ones, as disabled
  21  * and sets the IRQ_SUSPENDED flag for each of them.
  22  */
  23 void suspend_device_irqs(void)
  24 {
  25         struct irq_desc *desc;
  26         int irq;
  27
  28         for_each_irq_desc(irq, desc) {
  29                 unsigned long flags;
  30
  31                 spin_lock_irqsave(&desc->lock, flags);
  32                 __disable_irq(desc, irq, true);
  33                 spin_unlock_irqrestore(&desc->lock, flags);
  34         }
  35
  36         for_each_irq_desc(irq, desc)
  37                 if (desc->status & IRQ_SUSPENDED)
  38                         synchronize_irq(irq);
  39 }
  40 EXPORT_SYMBOL_GPL(suspend_device_irqs);
  41
  42 /**
  43  * resume_device_irqs - enable interrupt lines disabled by suspend_device_irqs()
  44  *
  45  * Enable all interrupt lines previously disabled by suspend_device_irqs() that
  46  * have the IRQ_SUSPENDED flag set.
  47  */
  48 void resume_device_irqs(void)
  49 {
  50         struct irq_desc *desc;
  51         int irq;
  52
  53         for_each_irq_desc(irq, desc) {
  54                 unsigned long flags;
  55
  56                 if (!(desc->status & IRQ_SUSPENDED))
  57                         continue;
  58
  59                 spin_lock_irqsave(&desc->lock, flags);
  60                 __enable_irq(desc, irq, true);
  61                 spin_unlock_irqrestore(&desc->lock, flags);
  62         }
  63 }
  64 EXPORT_SYMBOL_GPL(resume_device_irqs);
  65
  66 /**
  67  * check_wakeup_irqs - check if any wake-up interrupts are pending
  68  */
  69 int check_wakeup_irqs(void)
  70 {
  71         struct irq_desc *desc;
  72         int irq;
  73
  74         for_each_irq_desc(irq, desc)
  75                 if ((desc->status & IRQ_WAKEUP) && (desc->status & IRQ_PENDING))
  76                         return -EBUSY;
  77
  78         return 0;
  79 }