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_irq_wakeup(irq_desc_get_irq(desc));
  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)
  72 {
  73         if (!desc->action || irq_desc_is_chained(desc) ||
  74             desc->no_suspend_depth)
  75                 return false;
  76
  77         if (irqd_is_wakeup_set(&desc->irq_data)) {
  78                 irqd_set(&desc->irq_data, IRQD_WAKEUP_ARMED);
  79                 /*
  80                  * We return true here to force the caller to issue
  81                  * synchronize_irq(). We need to make sure that the
  82                  * IRQD_WAKEUP_ARMED is visible before we return from
  83                  * suspend_device_irqs().
  84                  */
  85                 return true;
  86         }
  87
  88         desc->istate |= IRQS_SUSPENDED;
  89         __disable_irq(desc);
  90
  91         /*
  92          * Hardware which has no wakeup source configuration facility
  93          * requires that the non wakeup interrupts are masked at the
  94          * chip level. The chip implementation indicates that with
  95          * IRQCHIP_MASK_ON_SUSPEND.
  96          */
  97         if (irq_desc_get_chip(desc)->flags & IRQCHIP_MASK_ON_SUSPEND)
  98                 mask_irq(desc);
  99         return true;
 100 }
 101
 102 /**
 103  * suspend_device_irqs - disable all currently enabled interrupt lines
 104  *
 105  * During system-wide suspend or hibernation device drivers need to be
 106  * prevented from receiving interrupts and this function is provided
 107  * for this purpose.
 108  *
 109  * So we disable all interrupts and mark them IRQS_SUSPENDED except
 110  * for those which are unused, those which are marked as not
 111  * suspendable via an interrupt request with the flag IRQF_NO_SUSPEND
 112  * set and those which are marked as active wakeup sources.
 113  *
 114  * The active wakeup sources are handled by the flow handler entry
 115  * code which checks for the IRQD_WAKEUP_ARMED flag, suspends the
 116  * interrupt and notifies the pm core about the wakeup.
 117  */
 118 void suspend_device_irqs(void)
 119 {
 120         struct irq_desc *desc;
 121         int irq;
 122
 123         for_each_irq_desc(irq, desc) {
 124                 unsigned long flags;
 125                 bool sync;
 126
 127                 if (irq_settings_is_nested_thread(desc))
 128                         continue;
 129                 raw_spin_lock_irqsave(&desc->lock, flags);
 130                 sync = suspend_device_irq(desc);
 131                 raw_spin_unlock_irqrestore(&desc->lock, flags);
 132
 133                 if (sync)
 134                         synchronize_irq(irq);
 135         }
 136 }
 137 EXPORT_SYMBOL_GPL(suspend_device_irqs);
 138
 139 static void resume_irq(struct irq_desc *desc)
 140 {
 141         irqd_clear(&desc->irq_data, IRQD_WAKEUP_ARMED);
 142
 143         if (desc->istate & IRQS_SUSPENDED)
 144                 goto resume;
 145
 146         /* Force resume the interrupt? */
 147         if (!desc->force_resume_depth)
 148                 return;
 149
 150         /* Pretend that it got disabled ! */
 151         desc->depth++;
 152 resume:
 153         desc->istate &= ~IRQS_SUSPENDED;
 154         __enable_irq(desc);
 155 }
 156
 157 static void resume_irqs(bool want_early)
 158 {
 159         struct irq_desc *desc;
 160         int irq;
 161
 162         for_each_irq_desc(irq, desc) {
 163                 unsigned long flags;
 164                 bool is_early = desc->action &&
 165                         desc->action->flags & IRQF_EARLY_RESUME;
 166
 167                 if (!is_early && want_early)
 168                         continue;
 169                 if (irq_settings_is_nested_thread(desc))
 170                         continue;
 171
 172                 raw_spin_lock_irqsave(&desc->lock, flags);
 173                 resume_irq(desc);
 174                 raw_spin_unlock_irqrestore(&desc->lock, flags);
 175         }
 176 }
 177
 178 /**
 179  * irq_pm_syscore_ops - enable interrupt lines early
 180  *
 181  * Enable all interrupt lines with %IRQF_EARLY_RESUME set.
 182  */
 183 static void irq_pm_syscore_resume(void)
 184 {
 185         resume_irqs(true);
 186 }
 187
 188 static struct syscore_ops irq_pm_syscore_ops = {
 189         .resume         = irq_pm_syscore_resume,
 190 };
 191
 192 static int __init irq_pm_init_ops(void)
 193 {
 194         register_syscore_ops(&irq_pm_syscore_ops);
 195         return 0;
 196 }
 197
 198 device_initcall(irq_pm_init_ops);
 199
 200 /**
 201  * resume_device_irqs - enable interrupt lines disabled by suspend_device_irqs()
 202  *
 203  * Enable all non-%IRQF_EARLY_RESUME interrupt lines previously
 204  * disabled by suspend_device_irqs() that have the IRQS_SUSPENDED flag
 205  * set as well as those with %IRQF_FORCE_RESUME.
 206  */
 207 void resume_device_irqs(void)
 208 {
 209         resume_irqs(false);
 210 }
 211 EXPORT_SYMBOL_GPL(resume_device_irqs);