d209a699a0
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>
92 lines
2.2 KiB
C
92 lines
2.2 KiB
C
/*
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* linux/kernel/irq/pm.c
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*
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* Copyright (C) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
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*
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* This file contains power management functions related to interrupts.
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*/
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#include <linux/irq.h>
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#include <linux/module.h>
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#include <linux/interrupt.h>
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#include "internals.h"
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/**
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* suspend_device_irqs - disable all currently enabled interrupt lines
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*
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* During system-wide suspend or hibernation device drivers need to be prevented
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* from receiving interrupts and this function is provided for this purpose.
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* It marks all interrupt lines in use, except for the timer ones, as disabled
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* and sets the IRQS_SUSPENDED flag for each of them.
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*/
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void suspend_device_irqs(void)
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{
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struct irq_desc *desc;
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int irq;
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for_each_irq_desc(irq, desc) {
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unsigned long flags;
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raw_spin_lock_irqsave(&desc->lock, flags);
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__disable_irq(desc, irq, true);
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raw_spin_unlock_irqrestore(&desc->lock, flags);
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}
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for_each_irq_desc(irq, desc)
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if (desc->istate & IRQS_SUSPENDED)
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synchronize_irq(irq);
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}
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EXPORT_SYMBOL_GPL(suspend_device_irqs);
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/**
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* resume_device_irqs - enable interrupt lines disabled by suspend_device_irqs()
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*
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* Enable all interrupt lines previously disabled by suspend_device_irqs() that
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* have the IRQS_SUSPENDED flag set.
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*/
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void resume_device_irqs(void)
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{
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struct irq_desc *desc;
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int irq;
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for_each_irq_desc(irq, desc) {
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unsigned long flags;
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raw_spin_lock_irqsave(&desc->lock, flags);
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__enable_irq(desc, irq, true);
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raw_spin_unlock_irqrestore(&desc->lock, flags);
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}
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}
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EXPORT_SYMBOL_GPL(resume_device_irqs);
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/**
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* check_wakeup_irqs - check if any wake-up interrupts are pending
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*/
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int check_wakeup_irqs(void)
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{
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struct irq_desc *desc;
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int irq;
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for_each_irq_desc(irq, desc) {
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if (irqd_is_wakeup_set(&desc->irq_data)) {
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if (desc->istate & IRQS_PENDING)
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return -EBUSY;
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continue;
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}
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/*
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* Check the non wakeup interrupts whether they need
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* to be masked before finally going into suspend
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* state. That's for hardware which has no wakeup
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* source configuration facility. The chip
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* implementation indicates that with
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* IRQCHIP_MASK_ON_SUSPEND.
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*/
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if (desc->istate & IRQS_SUSPENDED &&
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irq_desc_get_chip(desc)->flags & IRQCHIP_MASK_ON_SUSPEND)
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mask_irq(desc);
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}
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return 0;
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}
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