[net-next-2.6.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

cpumask_t irq_affinity[NR_IRQS] = { [0 ... NR_IRQS-1] = CPU_MASK_ALL };

#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)
{
	irq_desc_t *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->handler->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)
{
	irq_desc_t *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)
{
	irq_desc_t *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->handler,irq);
		}
		desc->handler->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->handler == &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;
	if ((old = *p) != NULL) {
		/* Can't share interrupts unless both agree to */
		if (!(old->flags & new->flags & SA_SHIRQ)) {
			spin_unlock_irqrestore(&desc->lock,flags);
			return -EBUSY;
		}

		/* add new interrupt at end of irq queue */
		do {
			p = &old->next;
			old = *p;
		} while (old);
		shared = 1;
	}

	*p = new;

	if (!shared) {
		desc->depth = 0;
		desc->status &= ~(IRQ_DISABLED | IRQ_AUTODETECT |
				  IRQ_WAITING | IRQ_INPROGRESS);
		if (desc->handler->startup)
			desc->handler->startup(irq);
		else
			desc->handler->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;
}

/**
 *	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;

	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->handler->release)
				desc->handler->release(irq, dev_id);
#endif

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