android_kernel_motorola_sm6225/kernel/irq/manage.c
David Brownell 15a647eba9 [PATCH] genirq: {en,dis}able_irq_wake() need refcounting too
IRQs need refcounting and a state flag to track whether the the IRQ should
be enabled or disabled as a "normal IRQ" source after a series of calls to
{en,dis}able_irq().  For shared IRQs, the IRQ must be enabled so long as at
least one driver needs it active.

Likewise, IRQs need the same support to track whether the IRQ should be
enabled or disabled as a "wakeup event" source after a series of calls to
{en,dis}able_irq_wake().  For shared IRQs, the IRQ must be enabled as a
wakeup source during sleep so long as at least one driver needs it.  But
right now they _don't have_ that refcounting ...  which means sharing a
wakeup-capable IRQ can't work correctly in some configurations.

This patch adds the refcount and flag mechanisms to set_irq_wake() -- which
is what {en,dis}able_irq_wake() call -- and minimal documentation of what
the irq wake mechanism does.

Drivers relying on the older (broken) "toggle" semantics will trigger a
warning; that'll be a handful of drivers on ARM systems.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-31 13:28:36 -07:00

478 lines
12 KiB
C

/*
* 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 "internals.h"
#ifdef CONFIG_SMP
/**
* 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)
{
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);
/**
* 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);
switch (desc->depth) {
case 0:
printk(KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
WARN_ON(1);
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--;
}
spin_unlock_irqrestore(&desc->lock, flags);
}
EXPORT_SYMBOL(enable_irq);
/**
* 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 = -ENXIO;
int (*set_wake)(unsigned, unsigned) = desc->chip->set_wake;
/* 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)
desc->status |= IRQ_WAKEUP;
else
set_wake = NULL;
} else {
if (desc->wake_depth == 0) {
printk(KERN_WARNING "Unbalanced IRQ %d "
"wake disable\n", irq);
WARN_ON(1);
} else if (--desc->wake_depth == 0)
desc->status &= ~IRQ_WAKEUP;
else
set_wake = NULL;
}
if (set_wake)
ret = desc->chip->set_wake(irq, on);
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;
}
/*
* 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->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))
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;
}
*p = new;
#if defined(CONFIG_IRQ_PER_CPU)
if (new->flags & IRQF_PERCPU)
desc->status |= IRQ_PER_CPU;
#endif
if (!shared) {
irq_chip_set_defaults(desc->chip);
/* Setup the type (level, edge polarity) if configured: */
if (new->flags & IRQF_TRIGGER_MASK) {
if (desc->chip && desc->chip->set_type)
desc->chip->set_type(irq,
new->flags & IRQF_TRIGGER_MASK);
else
/*
* IRQF_TRIGGER_* but the PIC does not support
* multiple flow-types?
*/
printk(KERN_WARNING "No IRQF_TRIGGER set_type "
"function for IRQ %d (%s)\n", irq,
desc->chip ? desc->chip->name :
"unknown");
} else
compat_irq_chip_set_default_handler(desc);
desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
IRQ_INPROGRESS);
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;
}
spin_unlock_irqrestore(&desc->lock, flags);
new->irq = irq;
register_irq_proc(irq);
new->dir = NULL;
register_handler_proc(irq, new);
return 0;
mismatch:
spin_unlock_irqrestore(&desc->lock, flags);
if (!(new->flags & IRQF_PROBE_SHARED)) {
printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
dump_stack();
}
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);
kfree(action);
return;
}
printk(KERN_ERR "Trying to free already-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:
*
* 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,
irqreturn_t (*handler)(int, void *, struct pt_regs *),
unsigned long irqflags, const char *devname, void *dev_id)
{
struct irqaction *action;
int retval;
#ifdef CONFIG_LOCKDEP
/*
* Lockdep wants atomic interrupt handlers:
*/
irqflags |= SA_INTERRUPT;
#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;
select_smp_affinity(irq);
retval = setup_irq(irq, action);
if (retval)
kfree(action);
return retval;
}
EXPORT_SYMBOL(request_irq);