linux/kernel/irq/pm.c
NeilBrown 3c646f2c6a genirq: Don't suspend nested_thread irqs over system suspend
Nested IRQs can only fire when the parent irq fires.  So when the
parent is suspended, there is no need to suspend the child irq.

Suspending nested irqs can cause a problem is they are suspended or
resumed in the wrong order.  If an interrupt fires while the parent is
active but the child is suspended, then the interrupt will not be
acknowledged properly and so an interrupt storm can result.  This is
particularly likely if the parent is resumed before the child, and the
interrupt was raised during suspend.

Ensuring correct ordering would be possible, but it is simpler to just
never suspend nested interrupts.

Signed-off-by: NeilBrown <neil@brown.name>
Cc: GTA04 owners <gta04-owner@goldelico.com>
Cc: Kalle Jokiniemi <kalle.jokiniemi@jollamobile.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Link: http://lkml.kernel.org/r/20150517151934.2393e8f8@notabene.brown
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-05-18 17:23:47 +02:00

211 lines
5.1 KiB
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/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);