/*
 * linux/kernel/irq/pm.c
 *
 * Copyright (C) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
 *
 * This file contains power management functions related to interrupts.
 */

#include <linux/irq.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/suspend.h>
#include <linux/syscore_ops.h>

#include "internals.h"

bool irq_pm_check_wakeup(struct irq_desc *desc)
{
        if (irqd_is_wakeup_armed(&desc->irq_data)) {
                irqd_clear(&desc->irq_data, IRQD_WAKEUP_ARMED);
                desc->istate |= IRQS_SUSPENDED | IRQS_PENDING;
                desc->depth++;
                irq_disable(desc);
                pm_system_wakeup();
                return true;
        }
        return false;
}

/*
 * Called from __setup_irq() with desc->lock held after @action has
 * been installed in the action chain.
 */
void irq_pm_install_action(struct irq_desc *desc, struct irqaction *action)
{
        desc->nr_actions++;

        if (action->flags & IRQF_FORCE_RESUME)
                desc->force_resume_depth++;

        WARN_ON_ONCE(desc->force_resume_depth &&
                     desc->force_resume_depth != desc->nr_actions);

        if (action->flags & IRQF_NO_SUSPEND)
                desc->no_suspend_depth++;
        else if (action->flags & IRQF_COND_SUSPEND)
                desc->cond_suspend_depth++;

        WARN_ON_ONCE(desc->no_suspend_depth &&
                     (desc->no_suspend_depth +
                        desc->cond_suspend_depth) != desc->nr_actions);
}

/*
 * Called from __free_irq() with desc->lock held after @action has
 * been removed from the action chain.
 */
void irq_pm_remove_action(struct irq_desc *desc, struct irqaction *action)
{
        desc->nr_actions--;

        if (action->flags & IRQF_FORCE_RESUME)
                desc->force_resume_depth--;

        if (action->flags & IRQF_NO_SUSPEND)
                desc->no_suspend_depth--;
        else if (action->flags & IRQF_COND_SUSPEND)
                desc->cond_suspend_depth--;
}

static bool suspend_device_irq(struct irq_desc *desc, int irq)
{
        if (!desc->action || desc->no_suspend_depth)
                return false;

        if (irqd_is_wakeup_set(&desc->irq_data)) {
                irqd_set(&desc->irq_data, IRQD_WAKEUP_ARMED);
                /*
                 * We return true here to force the caller to issue
                 * synchronize_irq(). We need to make sure that the
                 * IRQD_WAKEUP_ARMED is visible before we return from
                 * suspend_device_irqs().
                 */
                return true;
        }

        desc->istate |= IRQS_SUSPENDED;
        __disable_irq(desc, irq);

        /*
         * Hardware which has no wakeup source configuration facility
         * requires that the non wakeup interrupts are masked at the
         * chip level. The chip implementation indicates that with
         * IRQCHIP_MASK_ON_SUSPEND.
         */
        if (irq_desc_get_chip(desc)->flags & IRQCHIP_MASK_ON_SUSPEND)
                mask_irq(desc);
        return true;
}

/**
 * suspend_device_irqs - disable all currently enabled interrupt lines
 *
 * During system-wide suspend or hibernation device drivers need to be
 * prevented from receiving interrupts and this function is provided
 * for this purpose.
 *
 * So we disable all interrupts and mark them IRQS_SUSPENDED except
 * for those which are unused, those which are marked as not
 * suspendable via an interrupt request with the flag IRQF_NO_SUSPEND
 * set and those which are marked as active wakeup sources.
 *
 * The active wakeup sources are handled by the flow handler entry
 * code which checks for the IRQD_WAKEUP_ARMED flag, suspends the
 * interrupt and notifies the pm core about the wakeup.
 */
void suspend_device_irqs(void)
{
        struct irq_desc *desc;
        int irq;

        for_each_irq_desc(irq, desc) {
                unsigned long flags;
                bool sync;

                if (irq_settings_is_nested_thread(desc))
                        continue;
                raw_spin_lock_irqsave(&desc->lock, flags);
                sync = suspend_device_irq(desc, irq);
                raw_spin_unlock_irqrestore(&desc->lock, flags);

                if (sync)
                        synchronize_irq(irq);
        }
}
EXPORT_SYMBOL_GPL(suspend_device_irqs);

static void resume_irq(struct irq_desc *desc, int irq)
{
        irqd_clear(&desc->irq_data, IRQD_WAKEUP_ARMED);

        if (desc->istate & IRQS_SUSPENDED)
                goto resume;

        /* Force resume the interrupt? */
        if (!desc->force_resume_depth)
                return;

        /* Pretend that it got disabled ! */
        desc->depth++;
resume:
        desc->istate &= ~IRQS_SUSPENDED;
        __enable_irq(desc, irq);
}

static void resume_irqs(bool want_early)
{
        struct irq_desc *desc;
        int irq;

        for_each_irq_desc(irq, desc) {
                unsigned long flags;
                bool is_early = desc->action &&
                        desc->action->flags & IRQF_EARLY_RESUME;

                if (!is_early && want_early)
                        continue;
                if (irq_settings_is_nested_thread(desc))
                        continue;

                raw_spin_lock_irqsave(&desc->lock, flags);
                resume_irq(desc, irq);
                raw_spin_unlock_irqrestore(&desc->lock, flags);
        }
}

/**
 * irq_pm_syscore_ops - enable interrupt lines early
 *
 * Enable all interrupt lines with %IRQF_EARLY_RESUME set.
 */
static void irq_pm_syscore_resume(void)
{
        resume_irqs(true);
}

static struct syscore_ops irq_pm_syscore_ops = {
        .resume         = irq_pm_syscore_resume,
};

static int __init irq_pm_init_ops(void)
{
        register_syscore_ops(&irq_pm_syscore_ops);
        return 0;
}

device_initcall(irq_pm_init_ops);

/**
 * resume_device_irqs - enable interrupt lines disabled by suspend_device_irqs()
 *
 * Enable all non-%IRQF_EARLY_RESUME interrupt lines previously
 * disabled by suspend_device_irqs() that have the IRQS_SUSPENDED flag
 * set as well as those with %IRQF_FORCE_RESUME.
 */
void resume_device_irqs(void)
{
        resume_irqs(false);
}
EXPORT_SYMBOL_GPL(resume_device_irqs);