You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
377 lines
9.1 KiB
377 lines
9.1 KiB
/*
|
|
* linux/kernel/irq/manage.c
|
|
*
|
|
* Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
|
|
*
|
|
* This file contains driver APIs to the irq subsystem.
|
|
*/
|
|
|
|
#include <linux/config.h>
|
|
#include <linux/irq.h>
|
|
#include <linux/module.h>
|
|
#include <linux/random.h>
|
|
#include <linux/interrupt.h>
|
|
|
|
#include "internals.h"
|
|
|
|
#ifdef CONFIG_SMP
|
|
|
|
cpumask_t irq_affinity[NR_IRQS] = { [0 ... NR_IRQS-1] = CPU_MASK_ALL };
|
|
|
|
#if defined (CONFIG_GENERIC_PENDING_IRQ) || defined (CONFIG_IRQBALANCE)
|
|
cpumask_t __cacheline_aligned pending_irq_cpumask[NR_IRQS];
|
|
#endif
|
|
|
|
/**
|
|
* 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;
|
|
|
|
if (irq >= NR_IRQS)
|
|
return;
|
|
|
|
while (desc->status & IRQ_INPROGRESS)
|
|
cpu_relax();
|
|
}
|
|
|
|
EXPORT_SYMBOL(synchronize_irq);
|
|
|
|
#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)
|
|
{
|
|
irq_desc_t *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->handler->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)
|
|
{
|
|
irq_desc_t *desc = irq_desc + irq;
|
|
|
|
if (irq >= NR_IRQS)
|
|
return;
|
|
|
|
disable_irq_nosync(irq);
|
|
if (desc->action)
|
|
synchronize_irq(irq);
|
|
}
|
|
|
|
EXPORT_SYMBOL(disable_irq);
|
|
|
|
/**
|
|
* 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)
|
|
{
|
|
irq_desc_t *desc = irq_desc + irq;
|
|
unsigned long flags;
|
|
|
|
if (irq >= NR_IRQS)
|
|
return;
|
|
|
|
spin_lock_irqsave(&desc->lock, flags);
|
|
switch (desc->depth) {
|
|
case 0:
|
|
WARN_ON(1);
|
|
break;
|
|
case 1: {
|
|
unsigned int status = desc->status & ~IRQ_DISABLED;
|
|
|
|
desc->status = status;
|
|
if ((status & (IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) {
|
|
desc->status = status | IRQ_REPLAY;
|
|
hw_resend_irq(desc->handler,irq);
|
|
}
|
|
desc->handler->enable(irq);
|
|
/* fall-through */
|
|
}
|
|
default:
|
|
desc->depth--;
|
|
}
|
|
spin_unlock_irqrestore(&desc->lock, flags);
|
|
}
|
|
|
|
EXPORT_SYMBOL(enable_irq);
|
|
|
|
/*
|
|
* 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)
|
|
return 0;
|
|
|
|
action = irq_desc[irq].action;
|
|
if (action)
|
|
if (irqflags & action->flags & SA_SHIRQ)
|
|
action = NULL;
|
|
|
|
return !action;
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
unsigned long flags;
|
|
int shared = 0;
|
|
|
|
if (irq >= NR_IRQS)
|
|
return -EINVAL;
|
|
|
|
if (desc->handler == &no_irq_type)
|
|
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 & SA_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;
|
|
if ((old = *p) != NULL) {
|
|
/* Can't share interrupts unless both agree to */
|
|
if (!(old->flags & new->flags & SA_SHIRQ)) {
|
|
spin_unlock_irqrestore(&desc->lock,flags);
|
|
return -EBUSY;
|
|
}
|
|
|
|
/* add new interrupt at end of irq queue */
|
|
do {
|
|
p = &old->next;
|
|
old = *p;
|
|
} while (old);
|
|
shared = 1;
|
|
}
|
|
|
|
*p = new;
|
|
|
|
if (!shared) {
|
|
desc->depth = 0;
|
|
desc->status &= ~(IRQ_DISABLED | IRQ_AUTODETECT |
|
|
IRQ_WAITING | IRQ_INPROGRESS);
|
|
if (desc->handler->startup)
|
|
desc->handler->startup(irq);
|
|
else
|
|
desc->handler->enable(irq);
|
|
}
|
|
spin_unlock_irqrestore(&desc->lock,flags);
|
|
|
|
new->irq = irq;
|
|
register_irq_proc(irq);
|
|
new->dir = NULL;
|
|
register_handler_proc(irq, new);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* 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;
|
|
|
|
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->handler->release)
|
|
desc->handler->release(irq, dev_id);
|
|
#endif
|
|
|
|
if (!desc->action) {
|
|
desc->status |= IRQ_DISABLED;
|
|
if (desc->handler->shutdown)
|
|
desc->handler->shutdown(irq);
|
|
else
|
|
desc->handler->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);
|
|
kfree(action);
|
|
return;
|
|
}
|
|
printk(KERN_ERR "Trying to free free IRQ%d\n",irq);
|
|
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:
|
|
*
|
|
* SA_SHIRQ Interrupt is shared
|
|
* SA_INTERRUPT Disable local interrupts while processing
|
|
* SA_SAMPLE_RANDOM The interrupt can be used for entropy
|
|
*
|
|
*/
|
|
int request_irq(unsigned int irq,
|
|
irqreturn_t (*handler)(int, void *, struct pt_regs *),
|
|
unsigned long irqflags, const char * devname, void *dev_id)
|
|
{
|
|
struct irqaction * action;
|
|
int retval;
|
|
|
|
/*
|
|
* 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 & SA_SHIRQ) && !dev_id)
|
|
return -EINVAL;
|
|
if (irq >= NR_IRQS)
|
|
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;
|
|
|
|
retval = setup_irq(irq, action);
|
|
if (retval)
|
|
kfree(action);
|
|
|
|
return retval;
|
|
}
|
|
|
|
EXPORT_SYMBOL(request_irq);
|
|
|
|
|