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DEFINITIONS
This source file includes following definitions.
- synchronize_irq
- irq_can_set_affinity
- irq_set_affinity
- irq_select_affinity
- disable_irq_nosync
- disable_irq
- __enable_irq
- enable_irq
- set_irq_wake_real
- set_irq_wake
- can_request_irq
- compat_irq_chip_set_default_handler
- __irq_set_trigger
- setup_irq
- free_irq
- request_irq
/*
* 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
if (desc->status & IRQ_MOVE_PCNTXT) {
unsigned long flags;
spin_lock_irqsave(&desc->lock, flags);
desc->chip->set_affinity(irq, cpumask);
spin_unlock_irqrestore(&desc->lock, flags);
} else
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);
return ret;
}
/*
* Internal function to register an irqaction - typically used to
* allocate special interrupts that are part of the architecture.
*/
int setup_irq(unsigned int irq, struct irqaction *new)
{
struct irq_desc *desc = irq_desc + irq;
struct irqaction *old, **p;
const char *old_name = NULL;
unsigned long flags;
int shared = 0;
int ret;
if (irq >= NR_IRQS)
return -EINVAL;
if (desc->chip == &no_irq_chip)
return -ENOSYS;
/*
* Some drivers like serial.c use request_irq() heavily,
* so we have to be careful not to interfere with a
* running system.
*/
if (new->flags & IRQF_SAMPLE_RANDOM) {
/*
* This function might sleep, we want to call it first,
* outside of the atomic block.
* Yes, this might clear the entropy pool if the wrong
* driver is attempted to be loaded, without actually
* installing a new handler, but is this really a problem,
* only the sysadmin is able to do this.
*/
rand_initialize_irq(irq);
}
/*
* The following block of code has to be executed atomically
*/
spin_lock_irqsave(&desc->lock, flags);
p = &desc->action;
old = *p;
if (old) {
/*
* Can't share interrupts unless both agree to and are
* the same type (level, edge, polarity). So both flag
* fields must have IRQF_SHARED set and the bits which
* set the trigger type must match.
*/
if (!((old->flags & new->flags) & IRQF_SHARED) ||
((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
old_name = old->name;
goto mismatch;
}
#if defined(CONFIG_IRQ_PER_CPU)
/* All handlers must agree on per-cpuness */
if ((old->flags & IRQF_PERCPU) !=
(new->flags & IRQF_PERCPU))
goto mismatch;
#endif
/* add new interrupt at end of irq queue */
do {
p = &old->next;
old = *p;
} while (old);
shared = 1;
}
if (!shared) {
irq_chip_set_defaults(desc->chip);
/* Setup the type (level, edge polarity) if configured: */
if (new->flags & IRQF_TRIGGER_MASK) {
ret = __irq_set_trigger(desc->chip, irq, new->flags);
if (ret) {
spin_unlock_irqrestore(&desc->lock, flags);
return ret;
}
} else
compat_irq_chip_set_default_handler(desc);
#if defined(CONFIG_IRQ_PER_CPU)
if (new->flags & IRQF_PERCPU)
desc->status |= IRQ_PER_CPU;
#endif
desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
if (!(desc->status & IRQ_NOAUTOEN)) {
desc->depth = 0;
desc->status &= ~IRQ_DISABLED;
if (desc->chip->startup)
desc->chip->startup(irq);
else
desc->chip->enable(irq);
} else
/* Undo nested disables: */
desc->depth = 1;
/* Set default affinity mask once everything is setup */
irq_select_affinity(irq);
}
*p = new;
/* Exclude IRQ from balancing */
if (new->flags & IRQF_NOBALANCING)
desc->status |= IRQ_NO_BALANCING;
/* Reset broken irq detection when installing new handler */
desc->irq_count = 0;
desc->irqs_unhandled = 0;
/*
* Check whether we disabled the irq via the spurious handler
* before. Reenable it and give it another chance.
*/
if (shared && (desc->status & IRQ_SPURIOUS_DISABLED)) {
desc->status &= ~IRQ_SPURIOUS_DISABLED;
__enable_irq(desc, irq);
}
spin_unlock_irqrestore(&desc->lock, flags);
new->irq = irq;
register_irq_proc(irq);
new->dir = NULL;
register_handler_proc(irq, new);
return 0;
mismatch:
#ifdef CONFIG_DEBUG_SHIRQ
if (!(new->flags & IRQF_PROBE_SHARED)) {
printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
if (old_name)
printk(KERN_ERR "current handler: %s\n", old_name);
dump_stack();
}
#endif
spin_unlock_irqrestore(&desc->lock, flags);
return -EBUSY;
}
/**
* free_irq - free an interrupt
* @irq: Interrupt line to free
* @dev_id: Device identity to free
*
* Remove an interrupt handler. The handler is removed and if the
* interrupt line is no longer in use by any driver it is disabled.
* On a shared IRQ the caller must ensure the interrupt is disabled
* on the card it drives before calling this function. The function
* does not return until any executing interrupts for this IRQ
* have completed.
*
* This function must not be called from interrupt context.
*/
void free_irq(unsigned int irq, void *dev_id)
{
struct irq_desc *desc;
struct irqaction **p;
unsigned long flags;
WARN_ON(in_interrupt());
if (irq >= NR_IRQS)
return;
desc = irq_desc + irq;
spin_lock_irqsave(&desc->lock, flags);
p = &desc->action;
for (;;) {
struct irqaction *action = *p;
if (action) {
struct irqaction **pp = p;
p = &action->next;
if (action->dev_id != dev_id)
continue;
/* Found it - now remove it from the list of entries */
*pp = action->next;
/* Currently used only by UML, might disappear one day.*/
#ifdef CONFIG_IRQ_RELEASE_METHOD
if (desc->chip->release)
desc->chip->release(irq, dev_id);
#endif
if (!desc->action) {
desc->status |= IRQ_DISABLED;
if (desc->chip->shutdown)
desc->chip->shutdown(irq);
else
desc->chip->disable(irq);
}
spin_unlock_irqrestore(&desc->lock, flags);
unregister_handler_proc(irq, action);
/* Make sure it's not being used on another CPU */
synchronize_irq(irq);
#ifdef CONFIG_DEBUG_SHIRQ
/*
* It's a shared IRQ -- the driver ought to be
* prepared for it to happen even now it's
* being freed, so let's make sure.... We do
* this after actually deregistering it, to
* make sure that a 'real' IRQ doesn't run in
* parallel with our fake
*/
if (action->flags & IRQF_SHARED) {
local_irq_save(flags);
action->handler(irq, dev_id);
local_irq_restore(flags);
}
#endif
kfree(action);
return;
}
printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq);
#ifdef CONFIG_DEBUG_SHIRQ
dump_stack();
#endif
spin_unlock_irqrestore(&desc->lock, flags);
return;
}
}
EXPORT_SYMBOL(free_irq);
/**
* request_irq - allocate an interrupt line
* @irq: Interrupt line to allocate
* @handler: Function to be called when the IRQ occurs
* @irqflags: Interrupt type flags
* @devname: An ascii name for the claiming device
* @dev_id: A cookie passed back to the handler function
*
* This call allocates interrupt resources and enables the
* interrupt line and IRQ handling. From the point this
* call is made your handler function may be invoked. Since
* your handler function must clear any interrupt the board
* raises, you must take care both to initialise your hardware
* and to set up the interrupt handler in the right order.
*
* Dev_id must be globally unique. Normally the address of the
* device data structure is used as the cookie. Since the handler
* receives this value it makes sense to use it.
*
* If your interrupt is shared you must pass a non NULL dev_id
* as this is required when freeing the interrupt.
*
* Flags:
*
* IRQF_SHARED Interrupt is shared
* IRQF_DISABLED Disable local interrupts while processing
* IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
*
*/
int request_irq(unsigned int irq, irq_handler_t handler,
unsigned long irqflags, const char *devname, void *dev_id)
{
struct irqaction *action;
int retval;
#ifdef CONFIG_LOCKDEP
/*
* Lockdep wants atomic interrupt handlers:
*/
irqflags |= IRQF_DISABLED;
#endif
/*
* Sanity-check: shared interrupts must pass in a real dev-ID,
* otherwise we'll have trouble later trying to figure out
* which interrupt is which (messes up the interrupt freeing
* logic etc).
*/
if ((irqflags & IRQF_SHARED) && !dev_id)
return -EINVAL;
if (irq >= NR_IRQS)
return -EINVAL;
if (irq_desc[irq].status & IRQ_NOREQUEST)
return -EINVAL;
if (!handler)
return -EINVAL;
action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
if (!action)
return -ENOMEM;
action->handler = handler;
action->flags = irqflags;
cpus_clear(action->mask);
action->name = devname;
action->next = NULL;
action->dev_id = dev_id;
#ifdef CONFIG_DEBUG_SHIRQ
if (irqflags & IRQF_SHARED) {
/*
* It's a shared IRQ -- the driver ought to be prepared for it
* to happen immediately, so let's make sure....
* We do this before actually registering it, to make sure that
* a 'real' IRQ doesn't run in parallel with our fake
*/
unsigned long flags;
local_irq_save(flags);
handler(irq, dev_id);
local_irq_restore(flags);
}
#endif
retval = setup_irq(irq, action);
if (retval)
kfree(action);
return retval;
}
EXPORT_SYMBOL(request_irq);