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/suspend.h>
  13 #include <linux/syscore_ops.h>
  14
  15 #include "internals.h"
  16
  17 bool irq_pm_check_wakeup(struct irq_desc *desc)
  18 {
  19         if (irqd_is_wakeup_armed(&desc->irq_data)) {
  20                 irqd_clear(&desc->irq_data, IRQD_WAKEUP_ARMED);
  21                 desc->istate |= IRQS_SUSPENDED | IRQS_PENDING;
  22                 desc->depth++;
  23                 irq_disable(desc);
  24                 pm_system_wakeup();
  25                 return true;
  26         }
  27         return false;
  28 }
  29
  30 /*
  31  * Called from __setup_irq() with desc->lock held after @action has
  32  * been installed in the action chain.
  33  */
  34 void irq_pm_install_action(struct irq_desc *desc, struct irqaction *action)
  35 {
  36         desc->nr_actions++;
  37
  38         if (action->flags & IRQF_FORCE_RESUME)
  39                 desc->force_resume_depth++;
  40
  41         WARN_ON_ONCE(desc->force_resume_depth &&
  42                      desc->force_resume_depth != desc->nr_actions);
  43
  44         if (action->flags & IRQF_NO_SUSPEND)
  45                 desc->no_suspend_depth++;
  46         else if (action->flags & IRQF_COND_SUSPEND)
  47                 desc->cond_suspend_depth++;
  48
  49         WARN_ON_ONCE(desc->no_suspend_depth &&
  50                      (desc->no_suspend_depth +
  51                         desc->cond_suspend_depth) != desc->nr_actions);
  52 }
  53
  54 /*
  55  * Called from __free_irq() with desc->lock held after @action has
  56  * been removed from the action chain.
  57  */
  58 void irq_pm_remove_action(struct irq_desc *desc, struct irqaction *action)
  59 {
  60         desc->nr_actions--;
  61
  62         if (action->flags & IRQF_FORCE_RESUME)
  63                 desc->force_resume_depth--;
  64
  65         if (action->flags & IRQF_NO_SUSPEND)
  66                 desc->no_suspend_depth--;
  67         else if (action->flags & IRQF_COND_SUSPEND)
  68                 desc->cond_suspend_depth--;
  69 }
  70
  71 static bool suspend_device_irq(struct irq_desc *desc, int irq)
  72 {
  73         if (!desc->action || desc->no_suspend_depth)
  74                 return false;
  75
  76         if (irqd_is_wakeup_set(&desc->irq_data)) {
  77                 irqd_set(&desc->irq_data, IRQD_WAKEUP_ARMED);
  78                 /*
  79                  * We return true here to force the caller to issue
  80                  * synchronize_irq(). We need to make sure that the
  81                  * IRQD_WAKEUP_ARMED is visible before we return from
  82                  * suspend_device_irqs().
  83                  */
  84                 return true;
  85         }
  86
  87         desc->istate |= IRQS_SUSPENDED;
  88         __disable_irq(desc, irq);
  89
  90         /*
  91          * Hardware which has no wakeup source configuration facility
  92          * requires that the non wakeup interrupts are masked at the
  93          * chip level. The chip implementation indicates that with
  94          * IRQCHIP_MASK_ON_SUSPEND.
  95          */
  96         if (irq_desc_get_chip(desc)->flags & IRQCHIP_MASK_ON_SUSPEND)
  97                 mask_irq(desc);
  98         return true;
  99 }
 100
 101 /**
 102  * suspend_device_irqs - disable all currently enabled interrupt lines
 103  *
 104  * During system-wide suspend or hibernation device drivers need to be
 105  * prevented from receiving interrupts and this function is provided
 106  * for this purpose.
 107  *
 108  * So we disable all interrupts and mark them IRQS_SUSPENDED except
 109  * for those which are unused, those which are marked as not
 110  * suspendable via an interrupt request with the flag IRQF_NO_SUSPEND
 111  * set and those which are marked as active wakeup sources.
 112  *
 113  * The active wakeup sources are handled by the flow handler entry
 114  * code which checks for the IRQD_WAKEUP_ARMED flag, suspends the
 115  * interrupt and notifies the pm core about the wakeup.
 116  */
 117 void suspend_device_irqs(void)
 118 {
 119         struct irq_desc *desc;
 120         int irq;
 121
 122         for_each_irq_desc(irq, desc) {
 123                 unsigned long flags;
 124                 bool sync;
 125
 126                 raw_spin_lock_irqsave(&desc->lock, flags);
 127                 sync = suspend_device_irq(desc, irq);
 128                 raw_spin_unlock_irqrestore(&desc->lock, flags);
 129
 130                 if (sync)
 131                         synchronize_irq(irq);
 132         }
 133 }
 134 EXPORT_SYMBOL_GPL(suspend_device_irqs);
 135
 136 static void resume_irq(struct irq_desc *desc, int irq)
 137 {
 138         irqd_clear(&desc->irq_data, IRQD_WAKEUP_ARMED);
 139
 140         if (desc->istate & IRQS_SUSPENDED)
 141                 goto resume;
 142
 143         /* Force resume the interrupt? */
 144         if (!desc->force_resume_depth)
 145                 return;
 146
 147         /* Pretend that it got disabled ! */
 148         desc->depth++;
 149 resume:
 150         desc->istate &= ~IRQS_SUSPENDED;
 151         __enable_irq(desc, irq);
 152 }
 153
 154 static void resume_irqs(bool want_early)
 155 {
 156         struct irq_desc *desc;
 157         int irq;
 158
 159         for_each_irq_desc(irq, desc) {
 160                 unsigned long flags;
 161                 bool is_early = desc->action &&
 162                         desc->action->flags & IRQF_EARLY_RESUME;
 163
 164                 if (!is_early && want_early)
 165                         continue;
 166
 167                 raw_spin_lock_irqsave(&desc->lock, flags);
 168                 resume_irq(desc, irq);
 169                 raw_spin_unlock_irqrestore(&desc->lock, flags);
 170         }
 171 }
 172
 173 /**
 174  * irq_pm_syscore_ops - enable interrupt lines early
 175  *
 176  * Enable all interrupt lines with %IRQF_EARLY_RESUME set.
 177  */
 178 static void irq_pm_syscore_resume(void)
 179 {
 180         resume_irqs(true);
 181 }
 182
 183 static struct syscore_ops irq_pm_syscore_ops = {
 184         .resume         = irq_pm_syscore_resume,
 185 };
 186
 187 static int __init irq_pm_init_ops(void)
 188 {
 189         register_syscore_ops(&irq_pm_syscore_ops);
 190         return 0;
 191 }
 192
 193 device_initcall(irq_pm_init_ops);
 194
 195 /**
 196  * resume_device_irqs - enable interrupt lines disabled by suspend_device_irqs()
 197  *
 198  * Enable all non-%IRQF_EARLY_RESUME interrupt lines previously
 199  * disabled by suspend_device_irqs() that have the IRQS_SUSPENDED flag
 200  * set as well as those with %IRQF_FORCE_RESUME.
 201  */
 202 void resume_device_irqs(void)
 203 {
 204         resume_irqs(false);
 205 }
 206 EXPORT_SYMBOL_GPL(resume_device_irqs);