pm.c

/*
 * 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/syscore_ops.h>

#include "internals.h"

static void suspend_device_irq(struct irq_desc *desc, int irq)
{
	if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND))
		return;

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

/**
 * 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 and those which are marked as not
 * suspendable via an interrupt request with the flag IRQF_NO_SUSPEND
 * set.
 */
void suspend_device_irqs(void)
{
	struct irq_desc *desc;
	int irq;

	for_each_irq_desc(irq, desc) {
		unsigned long flags;

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

	for_each_irq_desc(irq, desc)
		if (desc->istate & IRQS_SUSPENDED)
			synchronize_irq(irq);
}
EXPORT_SYMBOL_GPL(suspend_device_irqs);

static void resume_irq(struct irq_desc *desc, int irq)
{
	if (desc->istate & IRQS_SUSPENDED)
		goto resume;

	if (!desc->action)
		return;

	/* Interrupts marked with that flag are force reenabled */
	if (!(desc->action->flags & IRQF_FORCE_RESUME))
		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;

		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);

/**
 * check_wakeup_irqs - check if any wake-up interrupts are pending
 */
int check_wakeup_irqs(void)
{
	struct irq_desc *desc;
	int irq;

	for_each_irq_desc(irq, desc) {
		/*
		 * Only interrupts which are marked as wakeup source
		 * and have not been disabled before the suspend check
		 * can abort suspend.
		 */
		if (irqd_is_wakeup_set(&desc->irq_data)) {
			if (desc->depth == 1 && desc->istate & IRQS_PENDING)
				return -EBUSY;
			continue;
		}
		/*
		 * Check the non wakeup interrupts whether they need
		 * to be masked before finally going into suspend
		 * state. That's for hardware which has no wakeup
		 * source configuration facility. The chip
		 * implementation indicates that with
		 * IRQCHIP_MASK_ON_SUSPEND.
		 */
		if (desc->istate & IRQS_SUSPENDED &&
		    irq_desc_get_chip(desc)->flags & IRQCHIP_MASK_ON_SUSPEND)
			mask_irq(desc);
	}

	return 0;
}