android_kernel_samsung_msm8976/kernel/irq/pm.c
Thomas Gleixner d209a699a0 genirq: Add chip flag to force mask on suspend
On suspend we disable all interrupts in the core code, but this does
not mask the interrupt line in the default implementation as we use a
lazy disable approach. That means we mark the interrupt disabled, but
leave the hardware unmasked. That's an optimization because we avoid
the hardware access for the common case where no interrupt happens
after we marked it disabled. If an interrupt happens, then the
interrupt flow handler masks the line at the hardware level and marks
it pending.

Suspend makes use of this delayed disable as it "disables" all
interrupts when preparing the suspend transition. Right before the
system goes into hardware suspend state it checks whether one of the
interrupts which is marked as a wakeup interrupt came in after
disabling it.

Most interrupt chips have a separate register which selects the
interrupts which can wake up the system from suspend, so we don't have
to mask any on the non wakeup interrupts.

But now we have to deal with brilliant designed hardware which lacks
such a wakeup configuration facility. For such hardware it's necessary
to mask all non wakeup interrupts before going into suspend in order
to avoid the wakeup from random interrupts.

Rather than working around this in the affected interrupt chip
implementations we can solve this elegant in the core code itself.

Add a flag IRQCHIP_MASK_ON_SUSPEND which can be set by the irq chip
implementation to indicate, that the interrupts which are not selected
as wakeup sources must be masked in the suspend path. Mask them in the
loop which checks the wakeup interrupts pending flag.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
LKML-Reference: <alpine.LFD.2.00.1103112112310.2787@localhost6.localdomain6>
2011-03-12 11:12:58 +01:00

91 lines
2.2 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 "internals.h"
/**
* 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.
* It marks all interrupt lines in use, except for the timer ones, as disabled
* and sets the IRQS_SUSPENDED flag for each of them.
*/
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);
__disable_irq(desc, irq, true);
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);
/**
* resume_device_irqs - enable interrupt lines disabled by suspend_device_irqs()
*
* Enable all interrupt lines previously disabled by suspend_device_irqs() that
* have the IRQS_SUSPENDED flag set.
*/
void resume_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);
__enable_irq(desc, irq, true);
raw_spin_unlock_irqrestore(&desc->lock, flags);
}
}
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) {
if (irqd_is_wakeup_set(&desc->irq_data)) {
if (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;
}