[mirror_ubuntu-zesty-kernel.git] / kernel / irq / manage.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/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;

		/* 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
 */
int set_irq_wake(unsigned int irq, unsigned int on)
{
	struct irq_desc *desc = irq_desc + irq;
	unsigned long flags;
	int ret = -ENXIO;

	spin_lock_irqsave(&desc->lock, flags);
	if (desc->chip->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 & SA_SHIRQ)
			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_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 and are
		 * the same type (level, edge, polarity). So both flag
		 * fields must have SA_SHIRQ set and the bits which
		 * set the trigger type must match.
		 */
		if (!((old->flags & new->flags) & SA_SHIRQ) ||
		    ((old->flags ^ new->flags) & SA_TRIGGER_MASK))
			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) {
		irq_chip_set_defaults(desc->chip);

		/* Setup the type (level, edge polarity) if configured: */
		if (new->flags & SA_TRIGGER_MASK) {
			if (desc->chip && desc->chip->set_type)
				desc->chip->set_type(irq,
						new->flags & SA_TRIGGER_MASK);
			else
				/*
				 * SA_TRIGGER_* but the PIC does not support
				 * multiple flow-types?
				 */
				printk(KERN_WARNING "setup_irq(%d) SA_TRIGGER"
				       "set. No set_type function available\n",
				       irq);
		} 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 & 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 (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);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/kernel/irq/manage.c
	3	*
a34db9b2 IM	4	* Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
a34db9b2 IM	5	* Copyright (C) 2005-2006 Thomas Gleixner
1da177e4 LT	6	*
	7	* This file contains driver APIs to the irq subsystem.
	8	*/
	9
b77d6adc	10	#include <linux/config.h>
1da177e4 LT	11	#include <linux/irq.h>
	12	#include <linux/module.h>
	13	#include <linux/random.h>
	14	#include <linux/interrupt.h>
	15
	16	#include "internals.h"
	17
	18	#ifdef CONFIG_SMP
	19
1da177e4 LT	20	/**
1da177e4 LT	21	* synchronize_irq - wait for pending IRQ handlers (on other CPUs)
1e5d5331	22	* @irq: interrupt number to wait for
1da177e4 LT	23	*
	24	* This function waits for any pending IRQ handlers for this interrupt
	25	* to complete before returning. If you use this function while
	26	* holding a resource the IRQ handler may need you will deadlock.
	27	*
	28	* This function may be called - with care - from IRQ context.
	29	*/
	30	void synchronize_irq(unsigned int irq)
	31	{
	32	struct irq_desc *desc = irq_desc + irq;
	33
c2b5a251 MW	34	if (irq >= NR_IRQS)
	35	return;
	36
1da177e4 LT	37	while (desc->status & IRQ_INPROGRESS)
	38	cpu_relax();
	39	}
1da177e4 LT	40	EXPORT_SYMBOL(synchronize_irq);
	41
	42	#endif
	43
	44	/**
	45	* disable_irq_nosync - disable an irq without waiting
	46	* @irq: Interrupt to disable
	47	*
	48	* Disable the selected interrupt line. Disables and Enables are
	49	* nested.
	50	* Unlike disable_irq(), this function does not ensure existing
	51	* instances of the IRQ handler have completed before returning.
	52	*
	53	* This function may be called from IRQ context.
	54	*/
	55	void disable_irq_nosync(unsigned int irq)
	56	{
34ffdb72	57	struct irq_desc *desc = irq_desc + irq;
1da177e4 LT	58	unsigned long flags;
1da177e4 LT	59
c2b5a251 MW	60	if (irq >= NR_IRQS)
	61	return;
	62
1da177e4 LT	63	spin_lock_irqsave(&desc->lock, flags);
	64	if (!desc->depth++) {
	65	desc->status \|= IRQ_DISABLED;
d1bef4ed	66	desc->chip->disable(irq);
1da177e4 LT	67	}
	68	spin_unlock_irqrestore(&desc->lock, flags);
	69	}
1da177e4 LT	70	EXPORT_SYMBOL(disable_irq_nosync);
	71
	72	/**
	73	* disable_irq - disable an irq and wait for completion
	74	* @irq: Interrupt to disable
	75	*
	76	* Disable the selected interrupt line. Enables and Disables are
	77	* nested.
	78	* This function waits for any pending IRQ handlers for this interrupt
	79	* to complete before returning. If you use this function while
	80	* holding a resource the IRQ handler may need you will deadlock.
	81	*
	82	* This function may be called - with care - from IRQ context.
	83	*/
	84	void disable_irq(unsigned int irq)
	85	{
34ffdb72	86	struct irq_desc *desc = irq_desc + irq;
1da177e4	87
c2b5a251 MW	88	if (irq >= NR_IRQS)
	89	return;
	90
1da177e4 LT	91	disable_irq_nosync(irq);
	92	if (desc->action)
	93	synchronize_irq(irq);
	94	}
1da177e4 LT	95	EXPORT_SYMBOL(disable_irq);
	96
	97	/**
	98	* enable_irq - enable handling of an irq
	99	* @irq: Interrupt to enable
	100	*
	101	* Undoes the effect of one call to disable_irq(). If this
	102	* matches the last disable, processing of interrupts on this
	103	* IRQ line is re-enabled.
	104	*
	105	* This function may be called from IRQ context.
	106	*/
	107	void enable_irq(unsigned int irq)
	108	{
34ffdb72	109	struct irq_desc *desc = irq_desc + irq;
1da177e4 LT	110	unsigned long flags;
1da177e4 LT	111
c2b5a251 MW	112	if (irq >= NR_IRQS)
	113	return;
	114
1da177e4 LT	115	spin_lock_irqsave(&desc->lock, flags);
	116	switch (desc->depth) {
	117	case 0:
096c8131	118	printk(KERN_WARNING "Unablanced enable_irq(%d)\n", irq);
1da177e4 LT	119	WARN_ON(1);
	120	break;
	121	case 1: {
3418d724 TG	122	unsigned int status = desc->status & ~IRQ_DISABLED;
	123
	124	/* Prevent probing on this irq: */
	125	desc->status = status \| IRQ_NOPROBE;
a4633adc	126	check_irq_resend(desc, irq);
1da177e4 LT	127	/* fall-through */
	128	}
	129	default:
	130	desc->depth--;
	131	}
	132	spin_unlock_irqrestore(&desc->lock, flags);
	133	}
1da177e4 LT	134	EXPORT_SYMBOL(enable_irq);
1da177e4 LT	135
ba9a2331 TG	136	/**
	137	* set_irq_wake - control irq power management wakeup
	138	* @irq: interrupt to control
	139	* @on: enable/disable power management wakeup
	140	*
	141	* Enable/disable power management wakeup mode
	142	*/
	143	int set_irq_wake(unsigned int irq, unsigned int on)
	144	{
	145	struct irq_desc *desc = irq_desc + irq;
	146	unsigned long flags;
	147	int ret = -ENXIO;
	148
	149	spin_lock_irqsave(&desc->lock, flags);
	150	if (desc->chip->set_wake)
	151	ret = desc->chip->set_wake(irq, on);
	152	spin_unlock_irqrestore(&desc->lock, flags);
	153	return ret;
	154	}
	155	EXPORT_SYMBOL(set_irq_wake);
	156
1da177e4 LT	157	/*
	158	* Internal function that tells the architecture code whether a
	159	* particular irq has been exclusively allocated or is available
	160	* for driver use.
	161	*/
	162	int can_request_irq(unsigned int irq, unsigned long irqflags)
	163	{
	164	struct irqaction *action;
	165
6550c775	166	if (irq >= NR_IRQS \|\| irq_desc[irq].status & IRQ_NOREQUEST)
1da177e4 LT	167	return 0;
	168
	169	action = irq_desc[irq].action;
	170	if (action)
	171	if (irqflags & action->flags & SA_SHIRQ)
	172	action = NULL;
	173
	174	return !action;
	175	}
	176
6a6de9ef TG	177	void compat_irq_chip_set_default_handler(struct irq_desc *desc)
	178	{
	179	/*
	180	* If the architecture still has not overriden
	181	* the flow handler then zap the default. This
	182	* should catch incorrect flow-type setting.
	183	*/
	184	if (desc->handle_irq == &handle_bad_irq)
	185	desc->handle_irq = NULL;
	186	}
	187
1da177e4 LT	188	/*
	189	* Internal function to register an irqaction - typically used to
	190	* allocate special interrupts that are part of the architecture.
	191	*/
06fcb0c6	192	int setup_irq(unsigned int irq, struct irqaction *new)
1da177e4 LT	193	{
	194	struct irq_desc *desc = irq_desc + irq;
	195	struct irqaction old, *p;
	196	unsigned long flags;
	197	int shared = 0;
	198
c2b5a251 MW	199	if (irq >= NR_IRQS)
	200	return -EINVAL;
	201
d1bef4ed	202	if (desc->chip == &no_irq_type)
1da177e4 LT	203	return -ENOSYS;
	204	/*
	205	* Some drivers like serial.c use request_irq() heavily,
	206	* so we have to be careful not to interfere with a
	207	* running system.
	208	*/
	209	if (new->flags & SA_SAMPLE_RANDOM) {
	210	/*
	211	* This function might sleep, we want to call it first,
	212	* outside of the atomic block.
	213	* Yes, this might clear the entropy pool if the wrong
	214	* driver is attempted to be loaded, without actually
	215	* installing a new handler, but is this really a problem,
	216	* only the sysadmin is able to do this.
	217	*/
	218	rand_initialize_irq(irq);
	219	}
	220
	221	/*
	222	* The following block of code has to be executed atomically
	223	*/
06fcb0c6	224	spin_lock_irqsave(&desc->lock, flags);
1da177e4	225	p = &desc->action;
06fcb0c6 IM	226	old = *p;
06fcb0c6 IM	227	if (old) {
e76de9f8 TG	228	/*
	229	* Can't share interrupts unless both agree to and are
	230	* the same type (level, edge, polarity). So both flag
	231	* fields must have SA_SHIRQ set and the bits which
	232	* set the trigger type must match.
	233	*/
	234	if (!((old->flags & new->flags) & SA_SHIRQ) \|\|
	235	((old->flags ^ new->flags) & SA_TRIGGER_MASK))
f5163427 DS	236	goto mismatch;
f5163427 DS	237
0d7012a9	238	#if defined(CONFIG_IRQ_PER_CPU) && defined(SA_PERCPU_IRQ)
f5163427 DS	239	/* All handlers must agree on per-cpuness */
	240	if ((old->flags & IRQ_PER_CPU) != (new->flags & IRQ_PER_CPU))
	241	goto mismatch;
	242	#endif
1da177e4 LT	243
	244	/* add new interrupt at end of irq queue */
	245	do {
	246	p = &old->next;
	247	old = *p;
	248	} while (old);
	249	shared = 1;
	250	}
	251
	252	*p = new;
0d7012a9	253	#if defined(CONFIG_IRQ_PER_CPU) && defined(SA_PERCPU_IRQ)
f5163427 DS	254	if (new->flags & SA_PERCPU_IRQ)
	255	desc->status \|= IRQ_PER_CPU;
	256	#endif
1da177e4	257	if (!shared) {
6a6de9ef	258	irq_chip_set_defaults(desc->chip);
e76de9f8 TG	259
	260	/* Setup the type (level, edge polarity) if configured: */
	261	if (new->flags & SA_TRIGGER_MASK) {
	262	if (desc->chip && desc->chip->set_type)
	263	desc->chip->set_type(irq,
	264	new->flags & SA_TRIGGER_MASK);
	265	else
	266	/*
	267	* SA_TRIGGER_* but the PIC does not support
	268	* multiple flow-types?
	269	*/
	270	printk(KERN_WARNING "setup_irq(%d) SA_TRIGGER"
	271	"set. No set_type function available\n",
	272	irq);
	273	} else
	274	compat_irq_chip_set_default_handler(desc);
6a6de9ef	275
94d39e1f TG	276	desc->status &= ~(IRQ_AUTODETECT \| IRQ_WAITING \|
	277	IRQ_INPROGRESS);
	278
	279	if (!(desc->status & IRQ_NOAUTOEN)) {
	280	desc->depth = 0;
	281	desc->status &= ~IRQ_DISABLED;
	282	if (desc->chip->startup)
	283	desc->chip->startup(irq);
	284	else
	285	desc->chip->enable(irq);
e76de9f8 TG	286	} else
	287	/* Undo nested disables: */
	288	desc->depth = 1;
1da177e4	289	}
06fcb0c6	290	spin_unlock_irqrestore(&desc->lock, flags);
1da177e4 LT	291
	292	new->irq = irq;
	293	register_irq_proc(irq);
	294	new->dir = NULL;
	295	register_handler_proc(irq, new);
	296
	297	return 0;
f5163427 DS	298
	299	mismatch:
	300	spin_unlock_irqrestore(&desc->lock, flags);
13e87ec6 AM	301	if (!(new->flags & SA_PROBEIRQ)) {
	302	printk(KERN_ERR "%s: irq handler mismatch\n", __FUNCTION__);
	303	dump_stack();
	304	}
f5163427	305	return -EBUSY;
1da177e4 LT	306	}
	307
	308	/**
	309	* free_irq - free an interrupt
	310	* @irq: Interrupt line to free
	311	* @dev_id: Device identity to free
	312	*
	313	* Remove an interrupt handler. The handler is removed and if the
	314	* interrupt line is no longer in use by any driver it is disabled.
	315	* On a shared IRQ the caller must ensure the interrupt is disabled
	316	* on the card it drives before calling this function. The function
	317	* does not return until any executing interrupts for this IRQ
	318	* have completed.
	319	*
	320	* This function must not be called from interrupt context.
	321	*/
	322	void free_irq(unsigned int irq, void *dev_id)
	323	{
	324	struct irq_desc *desc;
	325	struct irqaction **p;
	326	unsigned long flags;
	327
cd7b24bb	328	WARN_ON(in_interrupt());
1da177e4 LT	329	if (irq >= NR_IRQS)
	330	return;
	331
	332	desc = irq_desc + irq;
06fcb0c6	333	spin_lock_irqsave(&desc->lock, flags);
1da177e4 LT	334	p = &desc->action;
1da177e4 LT	335	for (;;) {
06fcb0c6	336	struct irqaction action = p;
1da177e4 LT	337
	338	if (action) {
	339	struct irqaction **pp = p;
	340
	341	p = &action->next;
	342	if (action->dev_id != dev_id)
	343	continue;
	344
	345	/* Found it - now remove it from the list of entries */
	346	*pp = action->next;
dbce706e	347
b77d6adc PBG	348	/* Currently used only by UML, might disappear one day.*/
b77d6adc PBG	349	#ifdef CONFIG_IRQ_RELEASE_METHOD
d1bef4ed IM	350	if (desc->chip->release)
d1bef4ed IM	351	desc->chip->release(irq, dev_id);
b77d6adc	352	#endif
dbce706e	353
1da177e4 LT	354	if (!desc->action) {
1da177e4 LT	355	desc->status \|= IRQ_DISABLED;
d1bef4ed IM	356	if (desc->chip->shutdown)
d1bef4ed IM	357	desc->chip->shutdown(irq);
1da177e4	358	else
d1bef4ed	359	desc->chip->disable(irq);
1da177e4	360	}
06fcb0c6	361	spin_unlock_irqrestore(&desc->lock, flags);
1da177e4 LT	362	unregister_handler_proc(irq, action);
	363
	364	/* Make sure it's not being used on another CPU */
	365	synchronize_irq(irq);
	366	kfree(action);
	367	return;
	368	}
06fcb0c6 IM	369	printk(KERN_ERR "Trying to free free IRQ%d\n", irq);
06fcb0c6 IM	370	spin_unlock_irqrestore(&desc->lock, flags);
1da177e4 LT	371	return;
	372	}
	373	}
1da177e4 LT	374	EXPORT_SYMBOL(free_irq);
	375
	376	/**
	377	* request_irq - allocate an interrupt line
	378	* @irq: Interrupt line to allocate
	379	* @handler: Function to be called when the IRQ occurs
	380	* @irqflags: Interrupt type flags
	381	* @devname: An ascii name for the claiming device
	382	* @dev_id: A cookie passed back to the handler function
	383	*
	384	* This call allocates interrupt resources and enables the
	385	* interrupt line and IRQ handling. From the point this
	386	* call is made your handler function may be invoked. Since
	387	* your handler function must clear any interrupt the board
	388	* raises, you must take care both to initialise your hardware
	389	* and to set up the interrupt handler in the right order.
	390	*
	391	* Dev_id must be globally unique. Normally the address of the
	392	* device data structure is used as the cookie. Since the handler
	393	* receives this value it makes sense to use it.
	394	*
	395	* If your interrupt is shared you must pass a non NULL dev_id
	396	* as this is required when freeing the interrupt.
	397	*
	398	* Flags:
	399	*
	400	* SA_SHIRQ Interrupt is shared
	401	* SA_INTERRUPT Disable local interrupts while processing
	402	* SA_SAMPLE_RANDOM The interrupt can be used for entropy
	403	*
	404	*/
	405	int request_irq(unsigned int irq,
	406	irqreturn_t (handler)(int, void , struct pt_regs *),
06fcb0c6	407	unsigned long irqflags, const char devname, void dev_id)
1da177e4	408	{
06fcb0c6	409	struct irqaction *action;
1da177e4 LT	410	int retval;
	411
	412	/*
	413	* Sanity-check: shared interrupts must pass in a real dev-ID,
	414	* otherwise we'll have trouble later trying to figure out
	415	* which interrupt is which (messes up the interrupt freeing
	416	* logic etc).
	417	*/
	418	if ((irqflags & SA_SHIRQ) && !dev_id)
	419	return -EINVAL;
	420	if (irq >= NR_IRQS)
	421	return -EINVAL;
6550c775 TG	422	if (irq_desc[irq].status & IRQ_NOREQUEST)
6550c775 TG	423	return -EINVAL;
1da177e4 LT	424	if (!handler)
	425	return -EINVAL;
	426
	427	action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
	428	if (!action)
	429	return -ENOMEM;
	430
	431	action->handler = handler;
	432	action->flags = irqflags;
	433	cpus_clear(action->mask);
	434	action->name = devname;
	435	action->next = NULL;
	436	action->dev_id = dev_id;
	437
eee45269 IK	438	select_smp_affinity(irq);
eee45269 IK	439
1da177e4 LT	440	retval = setup_irq(irq, action);
	441	if (retval)
	442	kfree(action);
	443
	444	return retval;
	445	}
1da177e4 LT	446	EXPORT_SYMBOL(request_irq);
1da177e4 LT	447