kernel_optimize_test/kernel/irq/manage.c
Rafael J. Wysocki 0a0c5168df PM: Introduce functions for suspending and resuming device interrupts
Introduce helper functions allowing us to prevent device drivers from
getting any interrupts (without disabling interrupts on the CPU)
during suspend (or hibernation) and to make them start to receive
interrupts again during the subsequent resume.  These functions make it
possible to keep timer interrupts enabled while the "late" suspend and
"early" resume callbacks provided by device drivers are being
executed.  In turn, this allows device drivers' "late" suspend and
"early" resume callbacks to sleep, execute ACPI callbacks etc.

The functions introduced here will be used to rework the handling of
interrupts during suspend (hibernation) and resume.  Namely,
interrupts will only be disabled on the CPU right before suspending
sysdevs, while device drivers will be prevented from receiving
interrupts, with the help of the new helper function, before their
"late" suspend callbacks run (and analogously during resume).

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Ingo Molnar <mingo@elte.hu>
2009-03-30 21:46:54 +02:00

792 lines
19 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 <linux/slab.h>
#include "internals.h"
#if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_HARDIRQS)
cpumask_var_t irq_default_affinity;
/**
* 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_to_desc(irq);
unsigned int status;
if (!desc)
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_to_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, const struct cpumask *cpumask)
{
struct irq_desc *desc = irq_to_desc(irq);
unsigned long flags;
if (!desc->chip->set_affinity)
return -EINVAL;
spin_lock_irqsave(&desc->lock, flags);
#ifdef CONFIG_GENERIC_PENDING_IRQ
if (desc->status & IRQ_MOVE_PCNTXT || desc->status & IRQ_DISABLED) {
cpumask_copy(desc->affinity, cpumask);
desc->chip->set_affinity(irq, cpumask);
} else {
desc->status |= IRQ_MOVE_PENDING;
cpumask_copy(desc->pending_mask, cpumask);
}
#else
cpumask_copy(desc->affinity, cpumask);
desc->chip->set_affinity(irq, cpumask);
#endif
desc->status |= IRQ_AFFINITY_SET;
spin_unlock_irqrestore(&desc->lock, flags);
return 0;
}
#ifndef CONFIG_AUTO_IRQ_AFFINITY
/*
* Generic version of the affinity autoselector.
*/
static int setup_affinity(unsigned int irq, struct irq_desc *desc)
{
if (!irq_can_set_affinity(irq))
return 0;
/*
* Preserve an userspace affinity setup, but make sure that
* one of the targets is online.
*/
if (desc->status & (IRQ_AFFINITY_SET | IRQ_NO_BALANCING)) {
if (cpumask_any_and(desc->affinity, cpu_online_mask)
< nr_cpu_ids)
goto set_affinity;
else
desc->status &= ~IRQ_AFFINITY_SET;
}
cpumask_and(desc->affinity, cpu_online_mask, irq_default_affinity);
set_affinity:
desc->chip->set_affinity(irq, desc->affinity);
return 0;
}
#else
static inline int setup_affinity(unsigned int irq, struct irq_desc *d)
{
return irq_select_affinity(irq);
}
#endif
/*
* Called when affinity is set via /proc/irq
*/
int irq_select_affinity_usr(unsigned int irq)
{
struct irq_desc *desc = irq_to_desc(irq);
unsigned long flags;
int ret;
spin_lock_irqsave(&desc->lock, flags);
ret = setup_affinity(irq, desc);
spin_unlock_irqrestore(&desc->lock, flags);
return ret;
}
#else
static inline int setup_affinity(unsigned int irq, struct irq_desc *desc)
{
return 0;
}
#endif
void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
{
if (suspend) {
if (!desc->action || (desc->action->flags & IRQF_TIMER))
return;
desc->status |= IRQ_SUSPENDED;
}
if (!desc->depth++) {
desc->status |= IRQ_DISABLED;
desc->chip->disable(irq);
}
}
/**
* 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_to_desc(irq);
unsigned long flags;
if (!desc)
return;
spin_lock_irqsave(&desc->lock, flags);
__disable_irq(desc, irq, false);
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_to_desc(irq);
if (!desc)
return;
disable_irq_nosync(irq);
if (desc->action)
synchronize_irq(irq);
}
EXPORT_SYMBOL(disable_irq);
void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume)
{
if (resume)
desc->status &= ~IRQ_SUSPENDED;
switch (desc->depth) {
case 0:
err_out:
WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
break;
case 1: {
unsigned int status = desc->status & ~IRQ_DISABLED;
if (desc->status & IRQ_SUSPENDED)
goto err_out;
/* 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_to_desc(irq);
unsigned long flags;
if (!desc)
return;
spin_lock_irqsave(&desc->lock, flags);
__enable_irq(desc, irq, false);
spin_unlock_irqrestore(&desc->lock, flags);
}
EXPORT_SYMBOL(enable_irq);
static int set_irq_wake_real(unsigned int irq, unsigned int on)
{
struct irq_desc *desc = irq_to_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_to_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 irq_desc *desc = irq_to_desc(irq);
struct irqaction *action;
if (!desc)
return 0;
if (desc->status & IRQ_NOREQUEST)
return 0;
action = desc->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;
}
int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
unsigned long flags)
{
int ret;
struct irq_chip *chip = desc->chip;
if (!chip || !chip->set_type) {
/*
* IRQF_TRIGGER_* but the PIC does not support multiple
* flow-types?
*/
pr_debug("No set_type function for IRQ %d (%s)\n", irq,
chip ? (chip->name ? : "unknown") : "unknown");
return 0;
}
/* caller masked out all except trigger mode flags */
ret = chip->set_type(irq, flags);
if (ret)
pr_err("setting trigger mode %d for irq %u failed (%pF)\n",
(int)flags, irq, chip->set_type);
else {
if (flags & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_LEVEL_HIGH))
flags |= IRQ_LEVEL;
/* note that IRQF_TRIGGER_MASK == IRQ_TYPE_SENSE_MASK */
desc->status &= ~(IRQ_LEVEL | IRQ_TYPE_SENSE_MASK);
desc->status |= flags;
}
return ret;
}
/*
* Internal function to register an irqaction - typically used to
* allocate special interrupts that are part of the architecture.
*/
static int
__setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
{
struct irqaction *old, **old_ptr;
const char *old_name = NULL;
unsigned long flags;
int shared = 0;
int ret;
if (!desc)
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);
old_ptr = &desc->action;
old = *old_ptr;
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 {
old_ptr = &old->next;
old = *old_ptr;
} 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, irq,
new->flags & IRQF_TRIGGER_MASK);
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;
desc->chip->startup(irq);
} else
/* Undo nested disables: */
desc->depth = 1;
/* Exclude IRQ from balancing if requested */
if (new->flags & IRQF_NOBALANCING)
desc->status |= IRQ_NO_BALANCING;
/* Set default affinity mask once everything is setup */
setup_affinity(irq, desc);
} else if ((new->flags & IRQF_TRIGGER_MASK)
&& (new->flags & IRQF_TRIGGER_MASK)
!= (desc->status & IRQ_TYPE_SENSE_MASK)) {
/* hope the handler works with the actual trigger mode... */
pr_warning("IRQ %d uses trigger mode %d; requested %d\n",
irq, (int)(desc->status & IRQ_TYPE_SENSE_MASK),
(int)(new->flags & IRQF_TRIGGER_MASK));
}
*old_ptr = new;
/* 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, false);
}
spin_unlock_irqrestore(&desc->lock, flags);
new->irq = irq;
register_irq_proc(irq, desc);
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;
}
/**
* setup_irq - setup an interrupt
* @irq: Interrupt line to setup
* @act: irqaction for the interrupt
*
* Used to statically setup interrupts in the early boot process.
*/
int setup_irq(unsigned int irq, struct irqaction *act)
{
struct irq_desc *desc = irq_to_desc(irq);
return __setup_irq(irq, desc, act);
}
EXPORT_SYMBOL_GPL(setup_irq);
/*
* Internal function to unregister an irqaction - used to free
* regular and special interrupts that are part of the architecture.
*/
static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
{
struct irq_desc *desc = irq_to_desc(irq);
struct irqaction *action, **action_ptr;
unsigned long flags;
WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
if (!desc)
return NULL;
spin_lock_irqsave(&desc->lock, flags);
/*
* There can be multiple actions per IRQ descriptor, find the right
* one based on the dev_id:
*/
action_ptr = &desc->action;
for (;;) {
action = *action_ptr;
if (!action) {
WARN(1, "Trying to free already-free IRQ %d\n", irq);
spin_unlock_irqrestore(&desc->lock, flags);
return NULL;
}
if (action->dev_id == dev_id)
break;
action_ptr = &action->next;
}
/* Found it - now remove it from the list of entries: */
*action_ptr = 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 this was the last handler, shut down the IRQ line: */
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 an IRQ
* event to happen even now it's being freed, so let's make sure that
* is so by doing an extra call to the handler ....
*
* ( 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
return action;
}
/**
* remove_irq - free an interrupt
* @irq: Interrupt line to free
* @act: irqaction for the interrupt
*
* Used to remove interrupts statically setup by the early boot process.
*/
void remove_irq(unsigned int irq, struct irqaction *act)
{
__free_irq(irq, act->dev_id);
}
EXPORT_SYMBOL_GPL(remove_irq);
/**
* free_irq - free an interrupt allocated with request_irq
* @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)
{
kfree(__free_irq(irq, dev_id));
}
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
* IRQF_TRIGGER_* Specify active edge(s) or level
*
*/
int request_irq(unsigned int irq, irq_handler_t handler,
unsigned long irqflags, const char *devname, void *dev_id)
{
struct irqaction *action;
struct irq_desc *desc;
int retval;
/*
* handle_IRQ_event() always ignores IRQF_DISABLED except for
* the _first_ irqaction (sigh). That can cause oopsing, but
* the behavior is classified as "will not fix" so we need to
* start nudging drivers away from using that idiom.
*/
if ((irqflags & (IRQF_SHARED|IRQF_DISABLED)) ==
(IRQF_SHARED|IRQF_DISABLED)) {
pr_warning(
"IRQ %d/%s: IRQF_DISABLED is not guaranteed on shared IRQs\n",
irq, devname);
}
#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;
desc = irq_to_desc(irq);
if (!desc)
return -EINVAL;
if (desc->status & IRQ_NOREQUEST)
return -EINVAL;
if (!handler)
return -EINVAL;
action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
if (!action)
return -ENOMEM;
action->handler = handler;
action->flags = irqflags;
action->name = devname;
action->dev_id = dev_id;
retval = __setup_irq(irq, desc, action);
if (retval)
kfree(action);
#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 disable the irq to make sure that a 'real' IRQ doesn't
* run in parallel with our fake.
*/
unsigned long flags;
disable_irq(irq);
local_irq_save(flags);
handler(irq, dev_id);
local_irq_restore(flags);
enable_irq(irq);
}
#endif
return retval;
}
EXPORT_SYMBOL(request_irq);