[mirror_ubuntu-bionic-kernel.git] / kernel / irq / manage.c

/*
 * 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

#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)
{
	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:
		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->chip,irq);
		}
		desc->chip->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->chip == &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;
	old = *p;
	if (old) {
		/* Can't share interrupts unless both agree to */
		if (!(old->flags & new->flags & SA_SHIRQ))
			goto mismatch;

#if defined(ARCH_HAS_IRQ_PER_CPU) && defined(SA_PERCPU_IRQ)
		/* All handlers must agree on per-cpuness */
		if ((old->flags & IRQ_PER_CPU) != (new->flags & IRQ_PER_CPU))
			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(ARCH_HAS_IRQ_PER_CPU) && defined(SA_PERCPU_IRQ)
	if (new->flags & SA_PERCPU_IRQ)
		desc->status |= IRQ_PER_CPU;
#endif
	if (!shared) {
		desc->depth = 0;
		desc->status &= ~(IRQ_DISABLED | IRQ_AUTODETECT |
				  IRQ_WAITING | IRQ_INPROGRESS);
		if (desc->chip->startup)
			desc->chip->startup(irq);
		else
			desc->chip->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;

mismatch:
	spin_unlock_irqrestore(&desc->lock, flags);
	if (!(new->flags & SA_PROBEIRQ)) {
		printk(KERN_ERR "%s: irq handler mismatch\n", __FUNCTION__);
		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 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;

	select_smp_affinity(irq);

	retval = setup_irq(irq, action);
	if (retval)
		kfree(action);

	return retval;
}
EXPORT_SYMBOL(request_irq);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/kernel/irq/manage.c
	3	*
	4	* Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
	5	*
	6	* This file contains driver APIs to the irq subsystem.
	7	*/
	8
b77d6adc	9	#include <linux/config.h>
1da177e4 LT	10	#include <linux/irq.h>
	11	#include <linux/module.h>
	12	#include <linux/random.h>
	13	#include <linux/interrupt.h>
	14
	15	#include "internals.h"
	16
	17	#ifdef CONFIG_SMP
	18
54d5d424 AR	19	#if defined (CONFIG_GENERIC_PENDING_IRQ) \|\| defined (CONFIG_IRQBALANCE)
	20	cpumask_t __cacheline_aligned pending_irq_cpumask[NR_IRQS];
	21	#endif
	22
1da177e4 LT	23	/**
1da177e4 LT	24	* synchronize_irq - wait for pending IRQ handlers (on other CPUs)
1e5d5331	25	* @irq: interrupt number to wait for
1da177e4 LT	26	*
	27	* This function waits for any pending IRQ handlers for this interrupt
	28	* to complete before returning. If you use this function while
	29	* holding a resource the IRQ handler may need you will deadlock.
	30	*
	31	* This function may be called - with care - from IRQ context.
	32	*/
	33	void synchronize_irq(unsigned int irq)
	34	{
	35	struct irq_desc *desc = irq_desc + irq;
	36
c2b5a251 MW	37	if (irq >= NR_IRQS)
	38	return;
	39
1da177e4 LT	40	while (desc->status & IRQ_INPROGRESS)
	41	cpu_relax();
	42	}
1da177e4 LT	43	EXPORT_SYMBOL(synchronize_irq);
	44
	45	#endif
	46
	47	/**
	48	* disable_irq_nosync - disable an irq without waiting
	49	* @irq: Interrupt to disable
	50	*
	51	* Disable the selected interrupt line. Disables and Enables are
	52	* nested.
	53	* Unlike disable_irq(), this function does not ensure existing
	54	* instances of the IRQ handler have completed before returning.
	55	*
	56	* This function may be called from IRQ context.
	57	*/
	58	void disable_irq_nosync(unsigned int irq)
	59	{
34ffdb72	60	struct irq_desc *desc = irq_desc + irq;
1da177e4 LT	61	unsigned long flags;
1da177e4 LT	62
c2b5a251 MW	63	if (irq >= NR_IRQS)
	64	return;
	65
1da177e4 LT	66	spin_lock_irqsave(&desc->lock, flags);
	67	if (!desc->depth++) {
	68	desc->status \|= IRQ_DISABLED;
d1bef4ed	69	desc->chip->disable(irq);
1da177e4 LT	70	}
	71	spin_unlock_irqrestore(&desc->lock, flags);
	72	}
1da177e4 LT	73	EXPORT_SYMBOL(disable_irq_nosync);
	74
	75	/**
	76	* disable_irq - disable an irq and wait for completion
	77	* @irq: Interrupt to disable
	78	*
	79	* Disable the selected interrupt line. Enables and Disables are
	80	* nested.
	81	* This function waits for any pending IRQ handlers for this interrupt
	82	* to complete before returning. If you use this function while
	83	* holding a resource the IRQ handler may need you will deadlock.
	84	*
	85	* This function may be called - with care - from IRQ context.
	86	*/
	87	void disable_irq(unsigned int irq)
	88	{
34ffdb72	89	struct irq_desc *desc = irq_desc + irq;
1da177e4	90
c2b5a251 MW	91	if (irq >= NR_IRQS)
	92	return;
	93
1da177e4 LT	94	disable_irq_nosync(irq);
	95	if (desc->action)
	96	synchronize_irq(irq);
	97	}
1da177e4 LT	98	EXPORT_SYMBOL(disable_irq);
	99
	100	/**
	101	* enable_irq - enable handling of an irq
	102	* @irq: Interrupt to enable
	103	*
	104	* Undoes the effect of one call to disable_irq(). If this
	105	* matches the last disable, processing of interrupts on this
	106	* IRQ line is re-enabled.
	107	*
	108	* This function may be called from IRQ context.
	109	*/
	110	void enable_irq(unsigned int irq)
	111	{
34ffdb72	112	struct irq_desc *desc = irq_desc + irq;
1da177e4 LT	113	unsigned long flags;
1da177e4 LT	114
c2b5a251 MW	115	if (irq >= NR_IRQS)
	116	return;
	117
1da177e4 LT	118	spin_lock_irqsave(&desc->lock, flags);
	119	switch (desc->depth) {
	120	case 0:
	121	WARN_ON(1);
	122	break;
	123	case 1: {
	124	unsigned int status = desc->status & ~IRQ_DISABLED;
	125
	126	desc->status = status;
	127	if ((status & (IRQ_PENDING \| IRQ_REPLAY)) == IRQ_PENDING) {
	128	desc->status = status \| IRQ_REPLAY;
d1bef4ed	129	hw_resend_irq(desc->chip,irq);
1da177e4	130	}
d1bef4ed	131	desc->chip->enable(irq);
1da177e4 LT	132	/* fall-through */
	133	}
	134	default:
	135	desc->depth--;
	136	}
	137	spin_unlock_irqrestore(&desc->lock, flags);
	138	}
1da177e4 LT	139	EXPORT_SYMBOL(enable_irq);
	140
	141	/*
	142	* Internal function that tells the architecture code whether a
	143	* particular irq has been exclusively allocated or is available
	144	* for driver use.
	145	*/
	146	int can_request_irq(unsigned int irq, unsigned long irqflags)
	147	{
	148	struct irqaction *action;
	149
	150	if (irq >= NR_IRQS)
	151	return 0;
	152
	153	action = irq_desc[irq].action;
	154	if (action)
	155	if (irqflags & action->flags & SA_SHIRQ)
	156	action = NULL;
	157
	158	return !action;
	159	}
	160
	161	/*
	162	* Internal function to register an irqaction - typically used to
	163	* allocate special interrupts that are part of the architecture.
	164	*/
06fcb0c6	165	int setup_irq(unsigned int irq, struct irqaction *new)
1da177e4 LT	166	{
	167	struct irq_desc *desc = irq_desc + irq;
	168	struct irqaction old, *p;
	169	unsigned long flags;
	170	int shared = 0;
	171
c2b5a251 MW	172	if (irq >= NR_IRQS)
	173	return -EINVAL;
	174
d1bef4ed	175	if (desc->chip == &no_irq_type)
1da177e4 LT	176	return -ENOSYS;
	177	/*
	178	* Some drivers like serial.c use request_irq() heavily,
	179	* so we have to be careful not to interfere with a
	180	* running system.
	181	*/
	182	if (new->flags & SA_SAMPLE_RANDOM) {
	183	/*
	184	* This function might sleep, we want to call it first,
	185	* outside of the atomic block.
	186	* Yes, this might clear the entropy pool if the wrong
	187	* driver is attempted to be loaded, without actually
	188	* installing a new handler, but is this really a problem,
	189	* only the sysadmin is able to do this.
	190	*/
	191	rand_initialize_irq(irq);
	192	}
	193
	194	/*
	195	* The following block of code has to be executed atomically
	196	*/
06fcb0c6	197	spin_lock_irqsave(&desc->lock, flags);
1da177e4	198	p = &desc->action;
06fcb0c6 IM	199	old = *p;
06fcb0c6 IM	200	if (old) {
1da177e4	201	/* Can't share interrupts unless both agree to */
f5163427 DS	202	if (!(old->flags & new->flags & SA_SHIRQ))
	203	goto mismatch;
	204
	205	#if defined(ARCH_HAS_IRQ_PER_CPU) && defined(SA_PERCPU_IRQ)
	206	/* All handlers must agree on per-cpuness */
	207	if ((old->flags & IRQ_PER_CPU) != (new->flags & IRQ_PER_CPU))
	208	goto mismatch;
	209	#endif
1da177e4 LT	210
	211	/* add new interrupt at end of irq queue */
	212	do {
	213	p = &old->next;
	214	old = *p;
	215	} while (old);
	216	shared = 1;
	217	}
	218
	219	*p = new;
f5163427 DS	220	#if defined(ARCH_HAS_IRQ_PER_CPU) && defined(SA_PERCPU_IRQ)
	221	if (new->flags & SA_PERCPU_IRQ)
	222	desc->status \|= IRQ_PER_CPU;
	223	#endif
1da177e4 LT	224	if (!shared) {
	225	desc->depth = 0;
	226	desc->status &= ~(IRQ_DISABLED \| IRQ_AUTODETECT \|
	227	IRQ_WAITING \| IRQ_INPROGRESS);
d1bef4ed IM	228	if (desc->chip->startup)
d1bef4ed IM	229	desc->chip->startup(irq);
1da177e4	230	else
d1bef4ed	231	desc->chip->enable(irq);
1da177e4	232	}
06fcb0c6	233	spin_unlock_irqrestore(&desc->lock, flags);
1da177e4 LT	234
	235	new->irq = irq;
	236	register_irq_proc(irq);
	237	new->dir = NULL;
	238	register_handler_proc(irq, new);
	239
	240	return 0;
f5163427 DS	241
	242	mismatch:
	243	spin_unlock_irqrestore(&desc->lock, flags);
13e87ec6 AM	244	if (!(new->flags & SA_PROBEIRQ)) {
	245	printk(KERN_ERR "%s: irq handler mismatch\n", __FUNCTION__);
	246	dump_stack();
	247	}
f5163427	248	return -EBUSY;
1da177e4 LT	249	}
	250
	251	/**
	252	* free_irq - free an interrupt
	253	* @irq: Interrupt line to free
	254	* @dev_id: Device identity to free
	255	*
	256	* Remove an interrupt handler. The handler is removed and if the
	257	* interrupt line is no longer in use by any driver it is disabled.
	258	* On a shared IRQ the caller must ensure the interrupt is disabled
	259	* on the card it drives before calling this function. The function
	260	* does not return until any executing interrupts for this IRQ
	261	* have completed.
	262	*
	263	* This function must not be called from interrupt context.
	264	*/
	265	void free_irq(unsigned int irq, void *dev_id)
	266	{
	267	struct irq_desc *desc;
	268	struct irqaction **p;
	269	unsigned long flags;
	270
cd7b24bb	271	WARN_ON(in_interrupt());
1da177e4 LT	272	if (irq >= NR_IRQS)
	273	return;
	274
	275	desc = irq_desc + irq;
06fcb0c6	276	spin_lock_irqsave(&desc->lock, flags);
1da177e4 LT	277	p = &desc->action;
1da177e4 LT	278	for (;;) {
06fcb0c6	279	struct irqaction action = p;
1da177e4 LT	280
	281	if (action) {
	282	struct irqaction **pp = p;
	283
	284	p = &action->next;
	285	if (action->dev_id != dev_id)
	286	continue;
	287
	288	/* Found it - now remove it from the list of entries */
	289	*pp = action->next;
dbce706e	290
b77d6adc PBG	291	/* Currently used only by UML, might disappear one day.*/
b77d6adc PBG	292	#ifdef CONFIG_IRQ_RELEASE_METHOD
d1bef4ed IM	293	if (desc->chip->release)
d1bef4ed IM	294	desc->chip->release(irq, dev_id);
b77d6adc	295	#endif
dbce706e	296
1da177e4 LT	297	if (!desc->action) {
1da177e4 LT	298	desc->status \|= IRQ_DISABLED;
d1bef4ed IM	299	if (desc->chip->shutdown)
d1bef4ed IM	300	desc->chip->shutdown(irq);
1da177e4	301	else
d1bef4ed	302	desc->chip->disable(irq);
1da177e4	303	}
06fcb0c6	304	spin_unlock_irqrestore(&desc->lock, flags);
1da177e4 LT	305	unregister_handler_proc(irq, action);
	306
	307	/* Make sure it's not being used on another CPU */
	308	synchronize_irq(irq);
	309	kfree(action);
	310	return;
	311	}
06fcb0c6 IM	312	printk(KERN_ERR "Trying to free free IRQ%d\n", irq);
06fcb0c6 IM	313	spin_unlock_irqrestore(&desc->lock, flags);
1da177e4 LT	314	return;
	315	}
	316	}
1da177e4 LT	317	EXPORT_SYMBOL(free_irq);
	318
	319	/**
	320	* request_irq - allocate an interrupt line
	321	* @irq: Interrupt line to allocate
	322	* @handler: Function to be called when the IRQ occurs
	323	* @irqflags: Interrupt type flags
	324	* @devname: An ascii name for the claiming device
	325	* @dev_id: A cookie passed back to the handler function
	326	*
	327	* This call allocates interrupt resources and enables the
	328	* interrupt line and IRQ handling. From the point this
	329	* call is made your handler function may be invoked. Since
	330	* your handler function must clear any interrupt the board
	331	* raises, you must take care both to initialise your hardware
	332	* and to set up the interrupt handler in the right order.
	333	*
	334	* Dev_id must be globally unique. Normally the address of the
	335	* device data structure is used as the cookie. Since the handler
	336	* receives this value it makes sense to use it.
	337	*
	338	* If your interrupt is shared you must pass a non NULL dev_id
	339	* as this is required when freeing the interrupt.
	340	*
	341	* Flags:
	342	*
	343	* SA_SHIRQ Interrupt is shared
	344	* SA_INTERRUPT Disable local interrupts while processing
	345	* SA_SAMPLE_RANDOM The interrupt can be used for entropy
	346	*
	347	*/
	348	int request_irq(unsigned int irq,
	349	irqreturn_t (handler)(int, void , struct pt_regs *),
06fcb0c6	350	unsigned long irqflags, const char devname, void dev_id)
1da177e4	351	{
06fcb0c6	352	struct irqaction *action;
1da177e4 LT	353	int retval;
	354
	355	/*
	356	* Sanity-check: shared interrupts must pass in a real dev-ID,
	357	* otherwise we'll have trouble later trying to figure out
	358	* which interrupt is which (messes up the interrupt freeing
	359	* logic etc).
	360	*/
	361	if ((irqflags & SA_SHIRQ) && !dev_id)
	362	return -EINVAL;
	363	if (irq >= NR_IRQS)
	364	return -EINVAL;
	365	if (!handler)
	366	return -EINVAL;
	367
	368	action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
	369	if (!action)
	370	return -ENOMEM;
	371
	372	action->handler = handler;
	373	action->flags = irqflags;
	374	cpus_clear(action->mask);
	375	action->name = devname;
	376	action->next = NULL;
	377	action->dev_id = dev_id;
	378
eee45269 IK	379	select_smp_affinity(irq);
eee45269 IK	380
1da177e4 LT	381	retval = setup_irq(irq, action);
	382	if (retval)
	383	kfree(action);
	384
	385	return retval;
	386	}
1da177e4 LT	387	EXPORT_SYMBOL(request_irq);
1da177e4 LT	388