manage.c

Kernel code of linux kernel

/*
 * linux/kernel/irq/manage.c
 *
 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
 * Copyright (C) 2005-2006 Thomas Gleixner
 *
 * This file contains driver APIs to the irq subsystem.
 */

#include <linux/irq.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/interrupt.h>
#include <linux/slab.h>

#include "internals.h"

#ifdef CONFIG_SMP

cpumask_t irq_default_affinity = CPU_MASK_ALL;

/**
 *	synchronize_irq - wait for pending IRQ handlers (on other CPUs)
 *	@irq: interrupt number to wait for
 *
 *	This function waits for any pending IRQ handlers for this interrupt
 *	to complete before returning. If you use this function while
 *	holding a resource the IRQ handler may need you will deadlock.
 *
 *	This function may be called - with care - from IRQ context.
 */
void synchronize_irq(unsigned int irq)
{
	struct irq_desc *desc = irq_desc + irq;
	unsigned int status;

	if (irq >= NR_IRQS)
		return;

	do {
		unsigned long flags;

		/*
		 * Wait until we're out of the critical section.  This might
		 * give the wrong answer due to the lack of memory barriers.
		 */
		while (desc->status & IRQ_INPROGRESS)
			cpu_relax();

		/* Ok, that indicated we're done: double-check carefully. */
		spin_lock_irqsave(&desc->lock, flags);
		status = desc->status;
		spin_unlock_irqrestore(&desc->lock, flags);

		/* Oops, that failed? */
	} while (status & IRQ_INPROGRESS);
}
EXPORT_SYMBOL(synchronize_irq);

/**
 *	irq_can_set_affinity - Check if the affinity of a given irq can be set
 *	@irq:		Interrupt to check
 *
 */
int irq_can_set_affinity(unsigned int irq)
{
	struct irq_desc *desc = irq_desc + irq;

	if (CHECK_IRQ_PER_CPU(desc->status) || !desc->chip ||
	    !desc->chip->set_affinity)
		return 0;

	return 1;
}

/**
 *	irq_set_affinity - Set the irq affinity of a given irq
 *	@irq:		Interrupt to set affinity
 *	@cpumask:	cpumask
 *
 */
int irq_set_affinity(unsigned int irq, cpumask_t cpumask)
{
	struct irq_desc *desc = irq_desc + irq;

	if (!desc->chip->set_affinity)
		return -EINVAL;

	set_balance_irq_affinity(irq, cpumask);

#ifdef CONFIG_GENERIC_PENDING_IRQ
	set_pending_irq(irq, cpumask);
#else
	desc->affinity = cpumask;
	desc->chip->set_affinity(irq, cpumask);
#endif
	return 0;
}

#ifndef CONFIG_AUTO_IRQ_AFFINITY
/*
 * Generic version of the affinity autoselector.
 */
int irq_select_affinity(unsigned int irq)
{
	cpumask_t mask;

	if (!irq_can_set_affinity(irq))
		return 0;

	cpus_and(mask, cpu_online_map, irq_default_affinity);

	irq_desc[irq].affinity = mask;
	irq_desc[irq].chip->set_affinity(irq, mask);

	set_balance_irq_affinity(irq, mask);
	return 0;
}
#endif

#endif

/**
 *	disable_irq_nosync - disable an irq without waiting
 *	@irq: Interrupt to disable
 *
 *	Disable the selected interrupt line.  Disables and Enables are
 *	nested.
 *	Unlike disable_irq(), this function does not ensure existing
 *	instances of the IRQ handler have completed before returning.
 *
 *	This function may be called from IRQ context.
 */
void disable_irq_nosync(unsigned int irq)
{
	struct irq_desc *desc = irq_desc + irq;
	unsigned long flags;

	if (irq >= NR_IRQS)
		return;

	spin_lock_irqsave(&desc->lock, flags);
	if (!desc->depth++) {
		desc->status |= IRQ_DISABLED;
		desc->chip->disable(irq);
	}
	spin_unlock_irqrestore(&desc->lock, flags);
}
EXPORT_SYMBOL(disable_irq_nosync);

/**
 *	disable_irq - disable an irq and wait for completion
 *	@irq: Interrupt to disable
 *
 *	Disable the selected interrupt line.  Enables and Disables are
 *	nested.
 *	This function waits for any pending IRQ handlers for this interrupt
 *	to complete before returning. If you use this function while
 *	holding a resource the IRQ handler may need you will deadlock.
 *
 *	This function may be called - with care - from IRQ context.
 */
void disable_irq(unsigned int irq)
{
	struct irq_desc *desc = irq_desc + irq;

	if (irq >= NR_IRQS)
		return;

	disable_irq_nosync(irq);
	if (desc->action)
		synchronize_irq(irq);
}
EXPORT_SYMBOL(disable_irq);

static void __enable_irq(struct irq_desc *desc, unsigned int irq)
{
	switch (desc->depth) {
	case 0:
		WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
		break;
	case 1: {
		unsigned int status = desc->status & ~IRQ_DISABLED;

		/* Prevent probing on this irq: */
		desc->status = status | IRQ_NOPROBE;
		check_irq_resend(desc, irq);
		/* fall-through */
	}
	default:
		desc->depth--;
	}
}

/**
 *	enable_irq - enable handling of an irq
 *	@irq: Interrupt to enable
 *
 *	Undoes the effect of one call to disable_irq().  If this
 *	matches the last disable, processing of interrupts on this
 *	IRQ line is re-enabled.
 *
 *	This function may be called from IRQ context.
 */
void enable_irq(unsigned int irq)
{
	struct irq_desc *desc = irq_desc + irq;
	unsigned long flags;

	if (irq >= NR_IRQS)
		return;

	spin_lock_irqsave(&desc->lock, flags);
	__enable_irq(desc, irq);
	spin_unlock_irqrestore(&desc->lock, flags);
}
EXPORT_SYMBOL(enable_irq);

int set_irq_wake_real(unsigned int irq, unsigned int on)
{
	struct irq_desc *desc = irq_desc + irq;
	int ret = -ENXIO;

	if (desc->chip->set_wake)
		ret = desc->chip->set_wake(irq, on);

	return ret;
}

/**
 *	set_irq_wake - control irq power management wakeup
 *	@irq:	interrupt to control
 *	@on:	enable/disable power management wakeup
 *
 *	Enable/disable power management wakeup mode, which is
 *	disabled by default.  Enables and disables must match,
 *	just as they match for non-wakeup mode support.
 *
 *	Wakeup mode lets this IRQ wake the system from sleep
 *	states like "suspend to RAM".
 */
int set_irq_wake(unsigned int irq, unsigned int on)
{
	struct irq_desc *desc = irq_desc + irq;
	unsigned long flags;
	int ret = 0;

	/* wakeup-capable irqs can be shared between drivers that
	 * don't need to have the same sleep mode behaviors.
	 */
	spin_lock_irqsave(&desc->lock, flags);
	if (on) {
		if (desc->wake_depth++ == 0) {
			ret = set_irq_wake_real(irq, on);
			if (ret)
				desc->wake_depth = 0;
			else
				desc->status |= IRQ_WAKEUP;
		}
	} else {
		if (desc->wake_depth == 0) {
			WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
		} else if (--desc->wake_depth == 0) {
			ret = set_irq_wake_real(irq, on);
			if (ret)
				desc->wake_depth = 1;
			else
				desc->status &= ~IRQ_WAKEUP;
		}
	}

	spin_unlock_irqrestore(&desc->lock, flags);
	return ret;
}
EXPORT_SYMBOL(set_irq_wake);

/*
 * Internal function that tells the architecture code whether a
 * particular irq has been exclusively allocated or is available
 * for driver use.
 */
int can_request_irq(unsigned int irq, unsigned long irqflags)
{
	struct irqaction *action;

	if (irq >= NR_IRQS || irq_desc[irq].status & IRQ_NOREQUEST)
		return 0;

	action = irq_desc[irq].action;
	if (action)
		if (irqflags & action->flags & IRQF_SHARED)
			action = NULL;

	return !action;
}

void compat_irq_chip_set_default_handler(struct irq_desc *desc)
{
	/*
	 * If the architecture still has not overriden
	 * the flow handler then zap the default. This
	 * should catch incorrect flow-type setting.
	 */
	if (desc->handle_irq == &handle_bad_irq)
		desc->handle_irq = NULL;
}

static int __irq_set_trigger(struct irq_chip *chip, unsigned int irq,
		unsigned long flags)
{
	int ret;

	if (!chip || !chip->set_type) {
		/*
		 * IRQF_TRIGGER_* but the PIC does not support multiple
		 * flow-types?
		 */
		pr_warning("No set_type function for IRQ %d (%s)\n", irq,
				chip ? (chip->name ? : "unknown") : "unknown");
		return 0;
	}

	ret = chip->set_type(irq, flags & IRQF_TRIGGER_MASK);

	if (ret)
		pr_err("setting trigger mode %d for irq %u failed (%pF)\n",
				(int)(flags & IRQF_TRIGGER_MASK),
				irq, chip->set_type);