[linux-2.6-block.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/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, irq_handler_t handler,
		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);
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
	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:
e8c4b9d0	117	printk(KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
1da177e4 LT	118	WARN_ON(1);
	119	break;
	120	case 1: {
3418d724 TG	121	unsigned int status = desc->status & ~IRQ_DISABLED;
	122
	123	/* Prevent probing on this irq: */
	124	desc->status = status \| IRQ_NOPROBE;
a4633adc	125	check_irq_resend(desc, irq);
1da177e4 LT	126	/* fall-through */
	127	}
	128	default:
	129	desc->depth--;
	130	}
	131	spin_unlock_irqrestore(&desc->lock, flags);
	132	}
1da177e4 LT	133	EXPORT_SYMBOL(enable_irq);
1da177e4 LT	134
ba9a2331 TG	135	/**
	136	* set_irq_wake - control irq power management wakeup
	137	* @irq: interrupt to control
	138	* @on: enable/disable power management wakeup
	139	*
15a647eb DB	140	* Enable/disable power management wakeup mode, which is
	141	* disabled by default. Enables and disables must match,
	142	* just as they match for non-wakeup mode support.
	143	*
	144	* Wakeup mode lets this IRQ wake the system from sleep
	145	* states like "suspend to RAM".
ba9a2331 TG	146	*/
	147	int set_irq_wake(unsigned int irq, unsigned int on)
	148	{
	149	struct irq_desc *desc = irq_desc + irq;
	150	unsigned long flags;
	151	int ret = -ENXIO;
15a647eb	152	int (*set_wake)(unsigned, unsigned) = desc->chip->set_wake;
ba9a2331	153
15a647eb DB	154	/* wakeup-capable irqs can be shared between drivers that
	155	* don't need to have the same sleep mode behaviors.
	156	*/
ba9a2331	157	spin_lock_irqsave(&desc->lock, flags);
15a647eb DB	158	if (on) {
	159	if (desc->wake_depth++ == 0)
	160	desc->status \|= IRQ_WAKEUP;
	161	else
	162	set_wake = NULL;
	163	} else {
	164	if (desc->wake_depth == 0) {
	165	printk(KERN_WARNING "Unbalanced IRQ %d "
	166	"wake disable\n", irq);
	167	WARN_ON(1);
	168	} else if (--desc->wake_depth == 0)
	169	desc->status &= ~IRQ_WAKEUP;
	170	else
	171	set_wake = NULL;
	172	}
	173	if (set_wake)
ba9a2331 TG	174	ret = desc->chip->set_wake(irq, on);
	175	spin_unlock_irqrestore(&desc->lock, flags);
	176	return ret;
	177	}
	178	EXPORT_SYMBOL(set_irq_wake);
	179
1da177e4 LT	180	/*
	181	* Internal function that tells the architecture code whether a
	182	* particular irq has been exclusively allocated or is available
	183	* for driver use.
	184	*/
	185	int can_request_irq(unsigned int irq, unsigned long irqflags)
	186	{
	187	struct irqaction *action;
	188
6550c775	189	if (irq >= NR_IRQS \|\| irq_desc[irq].status & IRQ_NOREQUEST)
1da177e4 LT	190	return 0;
	191
	192	action = irq_desc[irq].action;
	193	if (action)
3cca53b0	194	if (irqflags & action->flags & IRQF_SHARED)
1da177e4 LT	195	action = NULL;
	196
	197	return !action;
	198	}
	199
6a6de9ef TG	200	void compat_irq_chip_set_default_handler(struct irq_desc *desc)
	201	{
	202	/*
	203	* If the architecture still has not overriden
	204	* the flow handler then zap the default. This
	205	* should catch incorrect flow-type setting.
	206	*/
	207	if (desc->handle_irq == &handle_bad_irq)
	208	desc->handle_irq = NULL;
	209	}
	210
1da177e4 LT	211	/*
	212	* Internal function to register an irqaction - typically used to
	213	* allocate special interrupts that are part of the architecture.
	214	*/
06fcb0c6	215	int setup_irq(unsigned int irq, struct irqaction *new)
1da177e4 LT	216	{
	217	struct irq_desc *desc = irq_desc + irq;
	218	struct irqaction old, *p;
	219	unsigned long flags;
	220	int shared = 0;
	221
c2b5a251 MW	222	if (irq >= NR_IRQS)
	223	return -EINVAL;
	224
f1c2662c	225	if (desc->chip == &no_irq_chip)
1da177e4 LT	226	return -ENOSYS;
	227	/*
	228	* Some drivers like serial.c use request_irq() heavily,
	229	* so we have to be careful not to interfere with a
	230	* running system.
	231	*/
3cca53b0	232	if (new->flags & IRQF_SAMPLE_RANDOM) {
1da177e4 LT	233	/*
	234	* This function might sleep, we want to call it first,
	235	* outside of the atomic block.
	236	* Yes, this might clear the entropy pool if the wrong
	237	* driver is attempted to be loaded, without actually
	238	* installing a new handler, but is this really a problem,
	239	* only the sysadmin is able to do this.
	240	*/
	241	rand_initialize_irq(irq);
	242	}
	243
	244	/*
	245	* The following block of code has to be executed atomically
	246	*/
06fcb0c6	247	spin_lock_irqsave(&desc->lock, flags);
1da177e4	248	p = &desc->action;
06fcb0c6 IM	249	old = *p;
06fcb0c6 IM	250	if (old) {
e76de9f8 TG	251	/*
	252	* Can't share interrupts unless both agree to and are
	253	* the same type (level, edge, polarity). So both flag
3cca53b0	254	* fields must have IRQF_SHARED set and the bits which
e76de9f8 TG	255	* set the trigger type must match.
e76de9f8 TG	256	*/
3cca53b0 TG	257	if (!((old->flags & new->flags) & IRQF_SHARED) \|\|
3cca53b0 TG	258	((old->flags ^ new->flags) & IRQF_TRIGGER_MASK))
f5163427 DS	259	goto mismatch;
f5163427 DS	260
284c6680	261	#if defined(CONFIG_IRQ_PER_CPU)
f5163427	262	/* All handlers must agree on per-cpuness */
3cca53b0 TG	263	if ((old->flags & IRQF_PERCPU) !=
3cca53b0 TG	264	(new->flags & IRQF_PERCPU))
f5163427 DS	265	goto mismatch;
f5163427 DS	266	#endif
1da177e4 LT	267
	268	/* add new interrupt at end of irq queue */
	269	do {
	270	p = &old->next;
	271	old = *p;
	272	} while (old);
	273	shared = 1;
	274	}
	275
	276	*p = new;
284c6680	277	#if defined(CONFIG_IRQ_PER_CPU)
3cca53b0	278	if (new->flags & IRQF_PERCPU)
f5163427 DS	279	desc->status \|= IRQ_PER_CPU;
f5163427 DS	280	#endif
1da177e4	281	if (!shared) {
6a6de9ef	282	irq_chip_set_defaults(desc->chip);
e76de9f8 TG	283
e76de9f8 TG	284	/* Setup the type (level, edge polarity) if configured: */
3cca53b0	285	if (new->flags & IRQF_TRIGGER_MASK) {
e76de9f8 TG	286	if (desc->chip && desc->chip->set_type)
e76de9f8 TG	287	desc->chip->set_type(irq,
3cca53b0	288	new->flags & IRQF_TRIGGER_MASK);
e76de9f8 TG	289	else
e76de9f8 TG	290	/*
3cca53b0	291	* IRQF_TRIGGER_* but the PIC does not support
e76de9f8 TG	292	* multiple flow-types?
e76de9f8 TG	293	*/
3cca53b0	294	printk(KERN_WARNING "No IRQF_TRIGGER set_type "
e8c4b9d0 BH	295	"function for IRQ %d (%s)\n", irq,
	296	desc->chip ? desc->chip->name :
	297	"unknown");
e76de9f8 TG	298	} else
e76de9f8 TG	299	compat_irq_chip_set_default_handler(desc);
6a6de9ef	300
94d39e1f TG	301	desc->status &= ~(IRQ_AUTODETECT \| IRQ_WAITING \|
	302	IRQ_INPROGRESS);
	303
	304	if (!(desc->status & IRQ_NOAUTOEN)) {
	305	desc->depth = 0;
	306	desc->status &= ~IRQ_DISABLED;
	307	if (desc->chip->startup)
	308	desc->chip->startup(irq);
	309	else
	310	desc->chip->enable(irq);
e76de9f8 TG	311	} else
	312	/* Undo nested disables: */
	313	desc->depth = 1;
1da177e4	314	}
06fcb0c6	315	spin_unlock_irqrestore(&desc->lock, flags);
1da177e4 LT	316
	317	new->irq = irq;
	318	register_irq_proc(irq);
	319	new->dir = NULL;
	320	register_handler_proc(irq, new);
	321
	322	return 0;
f5163427 DS	323
	324	mismatch:
	325	spin_unlock_irqrestore(&desc->lock, flags);
3cca53b0	326	if (!(new->flags & IRQF_PROBE_SHARED)) {
e8c4b9d0	327	printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
13e87ec6 AM	328	dump_stack();
13e87ec6 AM	329	}
f5163427	330	return -EBUSY;
1da177e4 LT	331	}
	332
	333	/**
	334	* free_irq - free an interrupt
	335	* @irq: Interrupt line to free
	336	* @dev_id: Device identity to free
	337	*
	338	* Remove an interrupt handler. The handler is removed and if the
	339	* interrupt line is no longer in use by any driver it is disabled.
	340	* On a shared IRQ the caller must ensure the interrupt is disabled
	341	* on the card it drives before calling this function. The function
	342	* does not return until any executing interrupts for this IRQ
	343	* have completed.
	344	*
	345	* This function must not be called from interrupt context.
	346	*/
	347	void free_irq(unsigned int irq, void *dev_id)
	348	{
	349	struct irq_desc *desc;
	350	struct irqaction **p;
	351	unsigned long flags;
	352
cd7b24bb	353	WARN_ON(in_interrupt());
1da177e4 LT	354	if (irq >= NR_IRQS)
	355	return;
	356
	357	desc = irq_desc + irq;
06fcb0c6	358	spin_lock_irqsave(&desc->lock, flags);
1da177e4 LT	359	p = &desc->action;
1da177e4 LT	360	for (;;) {
06fcb0c6	361	struct irqaction action = p;
1da177e4 LT	362
	363	if (action) {
	364	struct irqaction **pp = p;
	365
	366	p = &action->next;
	367	if (action->dev_id != dev_id)
	368	continue;
	369
	370	/* Found it - now remove it from the list of entries */
	371	*pp = action->next;
dbce706e	372
b77d6adc PBG	373	/* Currently used only by UML, might disappear one day.*/
b77d6adc PBG	374	#ifdef CONFIG_IRQ_RELEASE_METHOD
d1bef4ed IM	375	if (desc->chip->release)
d1bef4ed IM	376	desc->chip->release(irq, dev_id);
b77d6adc	377	#endif
dbce706e	378
1da177e4 LT	379	if (!desc->action) {
1da177e4 LT	380	desc->status \|= IRQ_DISABLED;
d1bef4ed IM	381	if (desc->chip->shutdown)
d1bef4ed IM	382	desc->chip->shutdown(irq);
1da177e4	383	else
d1bef4ed	384	desc->chip->disable(irq);
1da177e4	385	}
06fcb0c6	386	spin_unlock_irqrestore(&desc->lock, flags);
1da177e4 LT	387	unregister_handler_proc(irq, action);
	388
	389	/* Make sure it's not being used on another CPU */
	390	synchronize_irq(irq);
	391	kfree(action);
	392	return;
	393	}
e8c4b9d0	394	printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq);
06fcb0c6	395	spin_unlock_irqrestore(&desc->lock, flags);
1da177e4 LT	396	return;
	397	}
	398	}
1da177e4 LT	399	EXPORT_SYMBOL(free_irq);
	400
	401	/**
	402	* request_irq - allocate an interrupt line
	403	* @irq: Interrupt line to allocate
	404	* @handler: Function to be called when the IRQ occurs
	405	* @irqflags: Interrupt type flags
	406	* @devname: An ascii name for the claiming device
	407	* @dev_id: A cookie passed back to the handler function
	408	*
	409	* This call allocates interrupt resources and enables the
	410	* interrupt line and IRQ handling. From the point this
	411	* call is made your handler function may be invoked. Since
	412	* your handler function must clear any interrupt the board
	413	* raises, you must take care both to initialise your hardware
	414	* and to set up the interrupt handler in the right order.
	415	*
	416	* Dev_id must be globally unique. Normally the address of the
	417	* device data structure is used as the cookie. Since the handler
	418	* receives this value it makes sense to use it.
	419	*
	420	* If your interrupt is shared you must pass a non NULL dev_id
	421	* as this is required when freeing the interrupt.
	422	*
	423	* Flags:
	424	*
3cca53b0 TG	425	* IRQF_SHARED Interrupt is shared
	426	* IRQF_DISABLED Disable local interrupts while processing
	427	* IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
1da177e4 LT	428	*
1da177e4 LT	429	*/
da482792	430	int request_irq(unsigned int irq, irq_handler_t handler,
06fcb0c6	431	unsigned long irqflags, const char devname, void dev_id)
1da177e4	432	{
06fcb0c6	433	struct irqaction *action;
1da177e4 LT	434	int retval;
1da177e4 LT	435
fbb9ce95 IM	436	#ifdef CONFIG_LOCKDEP
	437	/*
	438	* Lockdep wants atomic interrupt handlers:
	439	*/
	440	irqflags \|= SA_INTERRUPT;
	441	#endif
1da177e4 LT	442	/*
	443	* Sanity-check: shared interrupts must pass in a real dev-ID,
	444	* otherwise we'll have trouble later trying to figure out
	445	* which interrupt is which (messes up the interrupt freeing
	446	* logic etc).
	447	*/
3cca53b0	448	if ((irqflags & IRQF_SHARED) && !dev_id)
1da177e4 LT	449	return -EINVAL;
	450	if (irq >= NR_IRQS)
	451	return -EINVAL;
6550c775 TG	452	if (irq_desc[irq].status & IRQ_NOREQUEST)
6550c775 TG	453	return -EINVAL;
1da177e4 LT	454	if (!handler)
	455	return -EINVAL;
	456
	457	action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
	458	if (!action)
	459	return -ENOMEM;
	460
	461	action->handler = handler;
	462	action->flags = irqflags;
	463	cpus_clear(action->mask);
	464	action->name = devname;
	465	action->next = NULL;
	466	action->dev_id = dev_id;
	467
eee45269 IK	468	select_smp_affinity(irq);
eee45269 IK	469
1da177e4 LT	470	retval = setup_irq(irq, action);
	471	if (retval)
	472	kfree(action);
	473
	474	return retval;
	475	}
1da177e4	476	EXPORT_SYMBOL(request_irq);