[deliverable/linux.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

/**
 *	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 "Unablanced enable_irq(%d)\n", irq);
		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;
			if (desc->chip && desc->chip->retrigger)
				desc->chip->retrigger(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(CONFIG_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(CONFIG_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
1da177e4 LT	19	/**
1da177e4 LT	20	* synchronize_irq - wait for pending IRQ handlers (on other CPUs)
1e5d5331	21	* @irq: interrupt number to wait for
1da177e4 LT	22	*
	23	* This function waits for any pending IRQ handlers for this interrupt
	24	* to complete before returning. If you use this function while
	25	* holding a resource the IRQ handler may need you will deadlock.
	26	*
	27	* This function may be called - with care - from IRQ context.
	28	*/
	29	void synchronize_irq(unsigned int irq)
	30	{
	31	struct irq_desc *desc = irq_desc + irq;
	32
c2b5a251 MW	33	if (irq >= NR_IRQS)
	34	return;
	35
1da177e4 LT	36	while (desc->status & IRQ_INPROGRESS)
	37	cpu_relax();
	38	}
1da177e4 LT	39	EXPORT_SYMBOL(synchronize_irq);
	40
	41	#endif
	42
	43	/**
	44	* disable_irq_nosync - disable an irq without waiting
	45	* @irq: Interrupt to disable
	46	*
	47	* Disable the selected interrupt line. Disables and Enables are
	48	* nested.
	49	* Unlike disable_irq(), this function does not ensure existing
	50	* instances of the IRQ handler have completed before returning.
	51	*
	52	* This function may be called from IRQ context.
	53	*/
	54	void disable_irq_nosync(unsigned int irq)
	55	{
34ffdb72	56	struct irq_desc *desc = irq_desc + irq;
1da177e4 LT	57	unsigned long flags;
1da177e4 LT	58
c2b5a251 MW	59	if (irq >= NR_IRQS)
	60	return;
	61
1da177e4 LT	62	spin_lock_irqsave(&desc->lock, flags);
	63	if (!desc->depth++) {
	64	desc->status \|= IRQ_DISABLED;
d1bef4ed	65	desc->chip->disable(irq);
1da177e4 LT	66	}
	67	spin_unlock_irqrestore(&desc->lock, flags);
	68	}
1da177e4 LT	69	EXPORT_SYMBOL(disable_irq_nosync);
	70
	71	/**
	72	* disable_irq - disable an irq and wait for completion
	73	* @irq: Interrupt to disable
	74	*
	75	* Disable the selected interrupt line. Enables and Disables are
	76	* nested.
	77	* This function waits for any pending IRQ handlers for this interrupt
	78	* to complete before returning. If you use this function while
	79	* holding a resource the IRQ handler may need you will deadlock.
	80	*
	81	* This function may be called - with care - from IRQ context.
	82	*/
	83	void disable_irq(unsigned int irq)
	84	{
34ffdb72	85	struct irq_desc *desc = irq_desc + irq;
1da177e4	86
c2b5a251 MW	87	if (irq >= NR_IRQS)
	88	return;
	89
1da177e4 LT	90	disable_irq_nosync(irq);
	91	if (desc->action)
	92	synchronize_irq(irq);
	93	}
1da177e4 LT	94	EXPORT_SYMBOL(disable_irq);
	95
	96	/**
	97	* enable_irq - enable handling of an irq
	98	* @irq: Interrupt to enable
	99	*
	100	* Undoes the effect of one call to disable_irq(). If this
	101	* matches the last disable, processing of interrupts on this
	102	* IRQ line is re-enabled.
	103	*
	104	* This function may be called from IRQ context.
	105	*/
	106	void enable_irq(unsigned int irq)
	107	{
34ffdb72	108	struct irq_desc *desc = irq_desc + irq;
1da177e4 LT	109	unsigned long flags;
1da177e4 LT	110
c2b5a251 MW	111	if (irq >= NR_IRQS)
	112	return;
	113
1da177e4 LT	114	spin_lock_irqsave(&desc->lock, flags);
	115	switch (desc->depth) {
	116	case 0:
096c8131	117	printk(KERN_WARNING "Unablanced enable_irq(%d)\n", irq);
1da177e4 LT	118	WARN_ON(1);
	119	break;
	120	case 1: {
	121	unsigned int status = desc->status & ~IRQ_DISABLED;
	122
	123	desc->status = status;
	124	if ((status & (IRQ_PENDING \| IRQ_REPLAY)) == IRQ_PENDING) {
	125	desc->status = status \| IRQ_REPLAY;
c0ad90a3 IM	126	if (desc->chip && desc->chip->retrigger)
c0ad90a3 IM	127	desc->chip->retrigger(irq);
1da177e4	128	}
d1bef4ed	129	desc->chip->enable(irq);
1da177e4 LT	130	/* fall-through */
	131	}
	132	default:
	133	desc->depth--;
	134	}
	135	spin_unlock_irqrestore(&desc->lock, flags);
	136	}
1da177e4 LT	137	EXPORT_SYMBOL(enable_irq);
	138
	139	/*
	140	* Internal function that tells the architecture code whether a
	141	* particular irq has been exclusively allocated or is available
	142	* for driver use.
	143	*/
	144	int can_request_irq(unsigned int irq, unsigned long irqflags)
	145	{
	146	struct irqaction *action;
	147
	148	if (irq >= NR_IRQS)
	149	return 0;
	150
	151	action = irq_desc[irq].action;
	152	if (action)
	153	if (irqflags & action->flags & SA_SHIRQ)
	154	action = NULL;
	155
	156	return !action;
	157	}
	158
	159	/*
	160	* Internal function to register an irqaction - typically used to
	161	* allocate special interrupts that are part of the architecture.
	162	*/
06fcb0c6	163	int setup_irq(unsigned int irq, struct irqaction *new)
1da177e4 LT	164	{
	165	struct irq_desc *desc = irq_desc + irq;
	166	struct irqaction old, *p;
	167	unsigned long flags;
	168	int shared = 0;
	169
c2b5a251 MW	170	if (irq >= NR_IRQS)
	171	return -EINVAL;
	172
d1bef4ed	173	if (desc->chip == &no_irq_type)
1da177e4 LT	174	return -ENOSYS;
	175	/*
	176	* Some drivers like serial.c use request_irq() heavily,
	177	* so we have to be careful not to interfere with a
	178	* running system.
	179	*/
	180	if (new->flags & SA_SAMPLE_RANDOM) {
	181	/*
	182	* This function might sleep, we want to call it first,
	183	* outside of the atomic block.
	184	* Yes, this might clear the entropy pool if the wrong
	185	* driver is attempted to be loaded, without actually
	186	* installing a new handler, but is this really a problem,
	187	* only the sysadmin is able to do this.
	188	*/
	189	rand_initialize_irq(irq);
	190	}
	191
	192	/*
	193	* The following block of code has to be executed atomically
	194	*/
06fcb0c6	195	spin_lock_irqsave(&desc->lock, flags);
1da177e4	196	p = &desc->action;
06fcb0c6 IM	197	old = *p;
06fcb0c6 IM	198	if (old) {
1da177e4	199	/* Can't share interrupts unless both agree to */
f5163427 DS	200	if (!(old->flags & new->flags & SA_SHIRQ))
	201	goto mismatch;
	202
0d7012a9	203	#if defined(CONFIG_IRQ_PER_CPU) && defined(SA_PERCPU_IRQ)
f5163427 DS	204	/* All handlers must agree on per-cpuness */
	205	if ((old->flags & IRQ_PER_CPU) != (new->flags & IRQ_PER_CPU))
	206	goto mismatch;
	207	#endif
1da177e4 LT	208
	209	/* add new interrupt at end of irq queue */
	210	do {
	211	p = &old->next;
	212	old = *p;
	213	} while (old);
	214	shared = 1;
	215	}
	216
	217	*p = new;
0d7012a9	218	#if defined(CONFIG_IRQ_PER_CPU) && defined(SA_PERCPU_IRQ)
f5163427 DS	219	if (new->flags & SA_PERCPU_IRQ)
	220	desc->status \|= IRQ_PER_CPU;
	221	#endif
1da177e4 LT	222	if (!shared) {
	223	desc->depth = 0;
	224	desc->status &= ~(IRQ_DISABLED \| IRQ_AUTODETECT \|
	225	IRQ_WAITING \| IRQ_INPROGRESS);
d1bef4ed IM	226	if (desc->chip->startup)
d1bef4ed IM	227	desc->chip->startup(irq);
1da177e4	228	else
d1bef4ed	229	desc->chip->enable(irq);
1da177e4	230	}
06fcb0c6	231	spin_unlock_irqrestore(&desc->lock, flags);
1da177e4 LT	232
	233	new->irq = irq;
	234	register_irq_proc(irq);
	235	new->dir = NULL;
	236	register_handler_proc(irq, new);
	237
	238	return 0;
f5163427 DS	239
	240	mismatch:
	241	spin_unlock_irqrestore(&desc->lock, flags);
13e87ec6 AM	242	if (!(new->flags & SA_PROBEIRQ)) {
	243	printk(KERN_ERR "%s: irq handler mismatch\n", __FUNCTION__);
	244	dump_stack();
	245	}
f5163427	246	return -EBUSY;
1da177e4 LT	247	}
	248
	249	/**
	250	* free_irq - free an interrupt
	251	* @irq: Interrupt line to free
	252	* @dev_id: Device identity to free
	253	*
	254	* Remove an interrupt handler. The handler is removed and if the
	255	* interrupt line is no longer in use by any driver it is disabled.
	256	* On a shared IRQ the caller must ensure the interrupt is disabled
	257	* on the card it drives before calling this function. The function
	258	* does not return until any executing interrupts for this IRQ
	259	* have completed.
	260	*
	261	* This function must not be called from interrupt context.
	262	*/
	263	void free_irq(unsigned int irq, void *dev_id)
	264	{
	265	struct irq_desc *desc;
	266	struct irqaction **p;
	267	unsigned long flags;
	268
cd7b24bb	269	WARN_ON(in_interrupt());
1da177e4 LT	270	if (irq >= NR_IRQS)
	271	return;
	272
	273	desc = irq_desc + irq;
06fcb0c6	274	spin_lock_irqsave(&desc->lock, flags);
1da177e4 LT	275	p = &desc->action;
1da177e4 LT	276	for (;;) {
06fcb0c6	277	struct irqaction action = p;
1da177e4 LT	278
	279	if (action) {
	280	struct irqaction **pp = p;
	281
	282	p = &action->next;
	283	if (action->dev_id != dev_id)
	284	continue;
	285
	286	/* Found it - now remove it from the list of entries */
	287	*pp = action->next;
dbce706e	288
b77d6adc PBG	289	/* Currently used only by UML, might disappear one day.*/
b77d6adc PBG	290	#ifdef CONFIG_IRQ_RELEASE_METHOD
d1bef4ed IM	291	if (desc->chip->release)
d1bef4ed IM	292	desc->chip->release(irq, dev_id);
b77d6adc	293	#endif
dbce706e	294
1da177e4 LT	295	if (!desc->action) {
1da177e4 LT	296	desc->status \|= IRQ_DISABLED;
d1bef4ed IM	297	if (desc->chip->shutdown)
d1bef4ed IM	298	desc->chip->shutdown(irq);
1da177e4	299	else
d1bef4ed	300	desc->chip->disable(irq);
1da177e4	301	}
06fcb0c6	302	spin_unlock_irqrestore(&desc->lock, flags);
1da177e4 LT	303	unregister_handler_proc(irq, action);
	304
	305	/* Make sure it's not being used on another CPU */
	306	synchronize_irq(irq);
	307	kfree(action);
	308	return;
	309	}
06fcb0c6 IM	310	printk(KERN_ERR "Trying to free free IRQ%d\n", irq);
06fcb0c6 IM	311	spin_unlock_irqrestore(&desc->lock, flags);
1da177e4 LT	312	return;
	313	}
	314	}
1da177e4 LT	315	EXPORT_SYMBOL(free_irq);
	316
	317	/**
	318	* request_irq - allocate an interrupt line
	319	* @irq: Interrupt line to allocate
	320	* @handler: Function to be called when the IRQ occurs
	321	* @irqflags: Interrupt type flags
	322	* @devname: An ascii name for the claiming device
	323	* @dev_id: A cookie passed back to the handler function
	324	*
	325	* This call allocates interrupt resources and enables the
	326	* interrupt line and IRQ handling. From the point this
	327	* call is made your handler function may be invoked. Since
	328	* your handler function must clear any interrupt the board
	329	* raises, you must take care both to initialise your hardware
	330	* and to set up the interrupt handler in the right order.
	331	*
	332	* Dev_id must be globally unique. Normally the address of the
	333	* device data structure is used as the cookie. Since the handler
	334	* receives this value it makes sense to use it.
	335	*
	336	* If your interrupt is shared you must pass a non NULL dev_id
	337	* as this is required when freeing the interrupt.
	338	*
	339	* Flags:
	340	*
	341	* SA_SHIRQ Interrupt is shared
	342	* SA_INTERRUPT Disable local interrupts while processing
	343	* SA_SAMPLE_RANDOM The interrupt can be used for entropy
	344	*
	345	*/
	346	int request_irq(unsigned int irq,
	347	irqreturn_t (handler)(int, void , struct pt_regs *),
06fcb0c6	348	unsigned long irqflags, const char devname, void dev_id)
1da177e4	349	{
06fcb0c6	350	struct irqaction *action;
1da177e4 LT	351	int retval;
	352
	353	/*
	354	* Sanity-check: shared interrupts must pass in a real dev-ID,
	355	* otherwise we'll have trouble later trying to figure out
	356	* which interrupt is which (messes up the interrupt freeing
	357	* logic etc).
	358	*/
	359	if ((irqflags & SA_SHIRQ) && !dev_id)
	360	return -EINVAL;
	361	if (irq >= NR_IRQS)
	362	return -EINVAL;
	363	if (!handler)
	364	return -EINVAL;
	365
	366	action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
	367	if (!action)
	368	return -ENOMEM;
	369
	370	action->handler = handler;
	371	action->flags = irqflags;
	372	cpus_clear(action->mask);
	373	action->name = devname;
	374	action->next = NULL;
	375	action->dev_id = dev_id;
	376
eee45269 IK	377	select_smp_affinity(irq);
eee45269 IK	378
1da177e4 LT	379	retval = setup_irq(irq, action);
	380	if (retval)
	381	kfree(action);
	382
	383	return retval;
	384	}
1da177e4 LT	385	EXPORT_SYMBOL(request_irq);
1da177e4 LT	386