[linux-2.6-block.git] / kernel / irq / handle.c

/*
 * linux/kernel/irq/handle.c
 *
 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
 * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
 *
 * This file contains the core interrupt handling code.
 *
 * Detailed information is available in Documentation/DocBook/genericirq
 *
 */

#include <linux/irq.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/rculist.h>
#include <linux/hash.h>

#include "internals.h"

/*
 * lockdep: we want to handle all irq_desc locks as a single lock-class:
 */
static struct lock_class_key irq_desc_lock_class;

/**
 * handle_bad_irq - handle spurious and unhandled irqs
 * @irq:       the interrupt number
 * @desc:      description of the interrupt
 *
 * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
 */
void handle_bad_irq(unsigned int irq, struct irq_desc *desc)
{
	print_irq_desc(irq, desc);
	kstat_incr_irqs_this_cpu(irq, desc);
	ack_bad_irq(irq);
}

/*
 * Linux has a controller-independent interrupt architecture.
 * Every controller has a 'controller-template', that is used
 * by the main code to do the right thing. Each driver-visible
 * interrupt source is transparently wired to the appropriate
 * controller. Thus drivers need not be aware of the
 * interrupt-controller.
 *
 * The code is designed to be easily extended with new/different
 * interrupt controllers, without having to do assembly magic or
 * having to touch the generic code.
 *
 * Controller mappings for all interrupt sources:
 */
int nr_irqs = NR_IRQS;
EXPORT_SYMBOL_GPL(nr_irqs);

void __init __attribute__((weak)) arch_early_irq_init(void)
{
}

#ifdef CONFIG_SPARSE_IRQ
static struct irq_desc irq_desc_init = {
	.irq	    = -1,
	.status	    = IRQ_DISABLED,
	.chip	    = &no_irq_chip,
	.handle_irq = handle_bad_irq,
	.depth      = 1,
	.lock       = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
#ifdef CONFIG_SMP
	.affinity   = CPU_MASK_ALL
#endif
};

static void init_kstat_irqs(struct irq_desc *desc, int cpu, int nr)
{
	unsigned long bytes;
	char *ptr;
	int node;

	/* Compute how many bytes we need per irq and allocate them */
	bytes = nr * sizeof(unsigned int);

	node = cpu_to_node(cpu);
	ptr = kzalloc_node(bytes, GFP_ATOMIC, node);
	printk(KERN_DEBUG "  alloc kstat_irqs on cpu %d node %d\n", cpu, node);

	if (ptr)
		desc->kstat_irqs = (unsigned int *)ptr;
}

void __attribute__((weak)) arch_init_chip_data(struct irq_desc *desc, int cpu)
{
}

static void init_one_irq_desc(int irq, struct irq_desc *desc, int cpu)
{
	memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
	desc->irq = irq;
#ifdef CONFIG_SMP
	desc->cpu = cpu;
#endif
	lockdep_set_class(&desc->lock, &irq_desc_lock_class);
	init_kstat_irqs(desc, cpu, nr_cpu_ids);
	if (!desc->kstat_irqs) {
		printk(KERN_ERR "can not alloc kstat_irqs\n");
		BUG_ON(1);
	}
	arch_init_chip_data(desc, cpu);
}

/*
 * Protect the sparse_irqs:
 */
static DEFINE_SPINLOCK(sparse_irq_lock);

struct irq_desc *irq_desc_ptrs[NR_IRQS] __read_mostly;

static struct irq_desc irq_desc_legacy[16] __cacheline_aligned_in_smp = {
	[0 ... 15] = {
		.irq	    = -1,
		.status	    = IRQ_DISABLED,
		.chip	    = &no_irq_chip,
		.handle_irq = handle_bad_irq,
		.depth	    = 1,
		.lock	    = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
#ifdef CONFIG_SMP
		.affinity   = CPU_MASK_ALL
#endif
	}
};

/* FIXME: use bootmem alloc ...*/
static unsigned int kstat_irqs_legacy[16][NR_CPUS];

void __init early_irq_init(void)
{
	struct irq_desc *desc;
	int legacy_count;
	int i;

	desc = irq_desc_legacy;
	legacy_count = ARRAY_SIZE(irq_desc_legacy);

	for (i = 0; i < legacy_count; i++) {
		desc[i].irq = i;
		desc[i].kstat_irqs = kstat_irqs_legacy[i];

		irq_desc_ptrs[i] = desc + i;
	}

	for (i = legacy_count; i < NR_IRQS; i++)
		irq_desc_ptrs[i] = NULL;

	arch_early_irq_init();
}

struct irq_desc *irq_to_desc(unsigned int irq)
{
	return (irq < NR_IRQS) ? irq_desc_ptrs[irq] : NULL;
}

struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
{
	struct irq_desc *desc;
	unsigned long flags;
	int node;

	if (irq >= NR_IRQS) {
		printk(KERN_WARNING "irq >= NR_IRQS in irq_to_desc_alloc: %d %d\n",
				irq, NR_IRQS);
		WARN_ON(1);
		return NULL;
	}

	desc = irq_desc_ptrs[irq];
	if (desc)
		return desc;

	spin_lock_irqsave(&sparse_irq_lock, flags);

	/* We have to check it to avoid races with another CPU */
	desc = irq_desc_ptrs[irq];
	if (desc)
		goto out_unlock;

	node = cpu_to_node(cpu);
	desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
	printk(KERN_DEBUG "  alloc irq_desc for %d on cpu %d node %d\n",
		 irq, cpu, node);
	if (!desc) {
		printk(KERN_ERR "can not alloc irq_desc\n");
		BUG_ON(1);
	}
	init_one_irq_desc(irq, desc, cpu);

	irq_desc_ptrs[irq] = desc;

out_unlock:
	spin_unlock_irqrestore(&sparse_irq_lock, flags);

	return desc;
}

#else

struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
	[0 ... NR_IRQS-1] = {
		.status = IRQ_DISABLED,
		.chip = &no_irq_chip,
		.handle_irq = handle_bad_irq,
		.depth = 1,
		.lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
#ifdef CONFIG_SMP
		.affinity = CPU_MASK_ALL
#endif
	}
};

#endif

/*
 * What should we do if we get a hw irq event on an illegal vector?
 * Each architecture has to answer this themself.
 */
static void ack_bad(unsigned int irq)
{
	struct irq_desc *desc = irq_to_desc(irq);

	print_irq_desc(irq, desc);
	ack_bad_irq(irq);
}

/*
 * NOP functions
 */
static void noop(unsigned int irq)
{
}

static unsigned int noop_ret(unsigned int irq)
{
	return 0;
}

/*
 * Generic no controller implementation
 */
struct irq_chip no_irq_chip = {
	.name		= "none",
	.startup	= noop_ret,
	.shutdown	= noop,
	.enable		= noop,
	.disable	= noop,
	.ack		= ack_bad,
	.end		= noop,
};

/*
 * Generic dummy implementation which can be used for
 * real dumb interrupt sources
 */
struct irq_chip dummy_irq_chip = {
	.name		= "dummy",
	.startup	= noop_ret,
	.shutdown	= noop,
	.enable		= noop,
	.disable	= noop,
	.ack		= noop,
	.mask		= noop,
	.unmask		= noop,
	.end		= noop,
};

/*
 * Special, empty irq handler:
 */
irqreturn_t no_action(int cpl, void *dev_id)
{
	return IRQ_NONE;
}

/**
 * handle_IRQ_event - irq action chain handler
 * @irq:	the interrupt number
 * @action:	the interrupt action chain for this irq
 *
 * Handles the action chain of an irq event
 */
irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
{
	irqreturn_t ret, retval = IRQ_NONE;
	unsigned int status = 0;

	if (!(action->flags & IRQF_DISABLED))
		local_irq_enable_in_hardirq();

	do {
		ret = action->handler(irq, action->dev_id);
		if (ret == IRQ_HANDLED)
			status |= action->flags;
		retval |= ret;
		action = action->next;
	} while (action);

	if (status & IRQF_SAMPLE_RANDOM)
		add_interrupt_randomness(irq);
	local_irq_disable();

	return retval;
}

#ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
/**
 * __do_IRQ - original all in one highlevel IRQ handler
 * @irq:	the interrupt number
 *
 * __do_IRQ handles all normal device IRQ's (the special
 * SMP cross-CPU interrupts have their own specific
 * handlers).
 *
 * This is the original x86 implementation which is used for every
 * interrupt type.
 */
unsigned int __do_IRQ(unsigned int irq)
{
	struct irq_desc *desc = irq_to_desc(irq);
	struct irqaction *action;
	unsigned int status;

	kstat_incr_irqs_this_cpu(irq, desc);

	if (CHECK_IRQ_PER_CPU(desc->status)) {
		irqreturn_t action_ret;

		/*
		 * No locking required for CPU-local interrupts:
		 */
		if (desc->chip->ack)
			desc->chip->ack(irq);
		if (likely(!(desc->status & IRQ_DISABLED))) {
			action_ret = handle_IRQ_event(irq, desc->action);
			if (!noirqdebug)
				note_interrupt(irq, desc, action_ret);
		}
		desc->chip->end(irq);
		return 1;
	}

	spin_lock(&desc->lock);
	if (desc->chip->ack)
		desc->chip->ack(irq);
	/*
	 * REPLAY is when Linux resends an IRQ that was dropped earlier
	 * WAITING is used by probe to mark irqs that are being tested
	 */
	status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
	status |= IRQ_PENDING; /* we _want_ to handle it */

	/*
	 * If the IRQ is disabled for whatever reason, we cannot
	 * use the action we have.
	 */
	action = NULL;
	if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
		action = desc->action;
		status &= ~IRQ_PENDING; /* we commit to handling */
		status |= IRQ_INPROGRESS; /* we are handling it */
	}
	desc->status = status;

	/*
	 * If there is no IRQ handler or it was disabled, exit early.
	 * Since we set PENDING, if another processor is handling
	 * a different instance of this same irq, the other processor
	 * will take care of it.
	 */
	if (unlikely(!action))
		goto out;

	/*
	 * Edge triggered interrupts need to remember
	 * pending events.
	 * This applies to any hw interrupts that allow a second
	 * instance of the same irq to arrive while we are in do_IRQ
	 * or in the handler. But the code here only handles the _second_
	 * instance of the irq, not the third or fourth. So it is mostly
	 * useful for irq hardware that does not mask cleanly in an
	 * SMP environment.
	 */
	for (;;) {
		irqreturn_t action_ret;

		spin_unlock(&desc->lock);

		action_ret = handle_IRQ_event(irq, action);
		if (!noirqdebug)
			note_interrupt(irq, desc, action_ret);

		spin_lock(&desc->lock);
		if (likely(!(desc->status & IRQ_PENDING)))
			break;
		desc->status &= ~IRQ_PENDING;
	}
	desc->status &= ~IRQ_INPROGRESS;

out:
	/*
	 * The ->end() handler has to deal with interrupts which got
	 * disabled while the handler was running.
	 */
	desc->chip->end(irq);
	spin_unlock(&desc->lock);

	return 1;
}
#endif


#ifdef CONFIG_TRACE_IRQFLAGS
void early_init_irq_lock_class(void)
{
#ifndef CONFIG_SPARSE_IRQ
	struct irq_desc *desc;
	int i;

	for_each_irq_desc(i, desc) {
		if (!desc)
			continue;

		lockdep_set_class(&desc->lock, &irq_desc_lock_class);
	}
#endif
}
#endif

#ifdef CONFIG_SPARSE_IRQ
unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
{
	struct irq_desc *desc = irq_to_desc(irq);
	return desc->kstat_irqs[cpu];
}
#endif
EXPORT_SYMBOL(kstat_irqs_cpu);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/kernel/irq/handle.c
	3	*
a34db9b2 IM	4	* Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
a34db9b2 IM	5	* Copyright (C) 2005-2006, Thomas Gleixner, Russell King
1da177e4 LT	6	*
1da177e4 LT	7	* This file contains the core interrupt handling code.
a34db9b2 IM	8	*
	9	* Detailed information is available in Documentation/DocBook/genericirq
	10	*
1da177e4 LT	11	*/
	12
	13	#include <linux/irq.h>
	14	#include <linux/module.h>
	15	#include <linux/random.h>
	16	#include <linux/interrupt.h>
	17	#include <linux/kernel_stat.h>
0b8f1efa YL	18	#include <linux/rculist.h>
0b8f1efa YL	19	#include <linux/hash.h>
1da177e4 LT	20
	21	#include "internals.h"
	22
0b8f1efa YL	23	/*
	24	* lockdep: we want to handle all irq_desc locks as a single lock-class:
	25	*/
	26	static struct lock_class_key irq_desc_lock_class;
	27
6a6de9ef TG	28	/**
6a6de9ef TG	29	* handle_bad_irq - handle spurious and unhandled irqs
43a1dd50 HK	30	* @irq: the interrupt number
43a1dd50 HK	31	* @desc: description of the interrupt
43a1dd50 HK	32	*
43a1dd50 HK	33	* Handles spurious and unhandled IRQ's. It also prints a debugmessage.
6a6de9ef	34	*/
d6c88a50	35	void handle_bad_irq(unsigned int irq, struct irq_desc *desc)
6a6de9ef	36	{
43f77759	37	print_irq_desc(irq, desc);
d6c88a50	38	kstat_incr_irqs_this_cpu(irq, desc);
6a6de9ef TG	39	ack_bad_irq(irq);
	40	}
	41
1da177e4 LT	42	/*
	43	* Linux has a controller-independent interrupt architecture.
	44	* Every controller has a 'controller-template', that is used
	45	* by the main code to do the right thing. Each driver-visible
06fcb0c6	46	* interrupt source is transparently wired to the appropriate
1da177e4 LT	47	* controller. Thus drivers need not be aware of the
	48	* interrupt-controller.
	49	*
	50	* The code is designed to be easily extended with new/different
	51	* interrupt controllers, without having to do assembly magic or
	52	* having to touch the generic code.
	53	*
	54	* Controller mappings for all interrupt sources:
	55	*/
85c0f909	56	int nr_irqs = NR_IRQS;
fa42d10d	57	EXPORT_SYMBOL_GPL(nr_irqs);
d60458b2	58
0b8f1efa YL	59	void __init __attribute__((weak)) arch_early_irq_init(void)
	60	{
	61	}
	62
	63	#ifdef CONFIG_SPARSE_IRQ
	64	static struct irq_desc irq_desc_init = {
	65	.irq = -1,
	66	.status = IRQ_DISABLED,
	67	.chip = &no_irq_chip,
	68	.handle_irq = handle_bad_irq,
	69	.depth = 1,
	70	.lock = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
	71	#ifdef CONFIG_SMP
	72	.affinity = CPU_MASK_ALL
	73	#endif
	74	};
	75
	76	static void init_kstat_irqs(struct irq_desc *desc, int cpu, int nr)
	77	{
	78	unsigned long bytes;
	79	char *ptr;
	80	int node;
	81
	82	/* Compute how many bytes we need per irq and allocate them */
	83	bytes = nr * sizeof(unsigned int);
	84
	85	node = cpu_to_node(cpu);
	86	ptr = kzalloc_node(bytes, GFP_ATOMIC, node);
	87	printk(KERN_DEBUG " alloc kstat_irqs on cpu %d node %d\n", cpu, node);
	88
	89	if (ptr)
	90	desc->kstat_irqs = (unsigned int *)ptr;
	91	}
	92
	93	void __attribute__((weak)) arch_init_chip_data(struct irq_desc *desc, int cpu)
	94	{
	95	}
	96
	97	static void init_one_irq_desc(int irq, struct irq_desc *desc, int cpu)
	98	{
	99	memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
	100	desc->irq = irq;
	101	#ifdef CONFIG_SMP
	102	desc->cpu = cpu;
	103	#endif
	104	lockdep_set_class(&desc->lock, &irq_desc_lock_class);
	105	init_kstat_irqs(desc, cpu, nr_cpu_ids);
	106	if (!desc->kstat_irqs) {
	107	printk(KERN_ERR "can not alloc kstat_irqs\n");
	108	BUG_ON(1);
	109	}
	110	arch_init_chip_data(desc, cpu);
	111	}
	112
	113	/*
	114	* Protect the sparse_irqs:
	115	*/
	116	static DEFINE_SPINLOCK(sparse_irq_lock);
	117
	118	struct irq_desc *irq_desc_ptrs[NR_IRQS] __read_mostly;
	119
	120	static struct irq_desc irq_desc_legacy[16] __cacheline_aligned_in_smp = {
	121	[0 ... 15] = {
	122	.irq = -1,
123	.status = IRQ_DISABLED,
124	.chip = &no_irq_chip,
125	.handle_irq = handle_bad_irq,
126	.depth = 1,
127	.lock = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
128	#ifdef CONFIG_SMP
129	.affinity = CPU_MASK_ALL
130	#endif
131	}
132	};
133
134	/* FIXME: use bootmem alloc ...*/
135	static unsigned int kstat_irqs_legacy[16][NR_CPUS];
136
137	void __init early_irq_init(void)
138	{
139	struct irq_desc *desc;
140	int legacy_count;
141	int i;
142
143	desc = irq_desc_legacy;
144	legacy_count = ARRAY_SIZE(irq_desc_legacy);
145
146	for (i = 0; i < legacy_count; i++) {
147	desc[i].irq = i;
148	desc[i].kstat_irqs = kstat_irqs_legacy[i];
149
150	irq_desc_ptrs[i] = desc + i;
151	}
152
153	for (i = legacy_count; i < NR_IRQS; i++)
154	irq_desc_ptrs[i] = NULL;
155
156	arch_early_irq_init();
157	}
158
159	struct irq_desc *irq_to_desc(unsigned int irq)
160	{
161	return (irq < NR_IRQS) ? irq_desc_ptrs[irq] : NULL;
162	}
163
164	struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
165	{
166	struct irq_desc *desc;
167	unsigned long flags;
168	int node;
169
170	if (irq >= NR_IRQS) {
171	printk(KERN_WARNING "irq >= NR_IRQS in irq_to_desc_alloc: %d %d\n",
172	irq, NR_IRQS);
173	WARN_ON(1);
174	return NULL;
175	}
176
177	desc = irq_desc_ptrs[irq];
178	if (desc)
179	return desc;
180
181	spin_lock_irqsave(&sparse_irq_lock, flags);
182
183	/* We have to check it to avoid races with another CPU */
184	desc = irq_desc_ptrs[irq];
185	if (desc)
186	goto out_unlock;
187
188	node = cpu_to_node(cpu);
189	desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
190	printk(KERN_DEBUG " alloc irq_desc for %d on cpu %d node %d\n",
191	irq, cpu, node);
192	if (!desc) {
193	printk(KERN_ERR "can not alloc irq_desc\n");
194	BUG_ON(1);
195	}
196	init_one_irq_desc(irq, desc, cpu);
197
198	irq_desc_ptrs[irq] = desc;
199
200	out_unlock:
201	spin_unlock_irqrestore(&sparse_irq_lock, flags);
202
203	return desc;
204	}
205
206	#else
207
e729aa16	208	struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
1da177e4	209	[0 ... NR_IRQS-1] = {
4f167fb4	210	.status = IRQ_DISABLED,
f1c2662c	211	.chip = &no_irq_chip,
7a55713a	212	.handle_irq = handle_bad_irq,
94d39e1f	213	.depth = 1,
aac3f2b6	214	.lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
a53da52f IM	215	#ifdef CONFIG_SMP
	216	.affinity = CPU_MASK_ALL
	217	#endif
1da177e4 LT	218	}
1da177e4 LT	219	};
08678b08	220
0b8f1efa YL	221	#endif
0b8f1efa YL	222
1da177e4	223	/*
77a5afec IM	224	* What should we do if we get a hw irq event on an illegal vector?
77a5afec IM	225	* Each architecture has to answer this themself.
1da177e4	226	*/
77a5afec	227	static void ack_bad(unsigned int irq)
1da177e4	228	{
d3c60047	229	struct irq_desc *desc = irq_to_desc(irq);
08678b08	230
08678b08	231	print_irq_desc(irq, desc);
1da177e4 LT	232	ack_bad_irq(irq);
	233	}
	234
77a5afec IM	235	/*
	236	* NOP functions
	237	*/
	238	static void noop(unsigned int irq)
	239	{
	240	}
	241
	242	static unsigned int noop_ret(unsigned int irq)
	243	{
	244	return 0;
	245	}
	246
	247	/*
	248	* Generic no controller implementation
	249	*/
f1c2662c IM	250	struct irq_chip no_irq_chip = {
f1c2662c IM	251	.name = "none",
77a5afec IM	252	.startup = noop_ret,
	253	.shutdown = noop,
	254	.enable = noop,
	255	.disable = noop,
	256	.ack = ack_bad,
	257	.end = noop,
1da177e4 LT	258	};
1da177e4 LT	259
f8b5473f TG	260	/*
	261	* Generic dummy implementation which can be used for
	262	* real dumb interrupt sources
	263	*/
	264	struct irq_chip dummy_irq_chip = {
	265	.name = "dummy",
	266	.startup = noop_ret,
	267	.shutdown = noop,
	268	.enable = noop,
	269	.disable = noop,
	270	.ack = noop,
	271	.mask = noop,
	272	.unmask = noop,
	273	.end = noop,
	274	};
	275
1da177e4 LT	276	/*
	277	* Special, empty irq handler:
	278	*/
7d12e780	279	irqreturn_t no_action(int cpl, void *dev_id)
1da177e4 LT	280	{
	281	return IRQ_NONE;
	282	}
	283
8d28bc75 IM	284	/**
	285	* handle_IRQ_event - irq action chain handler
	286	* @irq: the interrupt number
8d28bc75 IM	287	* @action: the interrupt action chain for this irq
	288	*
	289	* Handles the action chain of an irq event
1da177e4	290	*/
7d12e780	291	irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
1da177e4	292	{
908dcecd JB	293	irqreturn_t ret, retval = IRQ_NONE;
908dcecd JB	294	unsigned int status = 0;
1da177e4	295
3cca53b0	296	if (!(action->flags & IRQF_DISABLED))
366c7f55	297	local_irq_enable_in_hardirq();
1da177e4 LT	298
1da177e4 LT	299	do {
7d12e780	300	ret = action->handler(irq, action->dev_id);
1da177e4 LT	301	if (ret == IRQ_HANDLED)
	302	status \|= action->flags;
	303	retval \|= ret;
	304	action = action->next;
	305	} while (action);
	306
3cca53b0	307	if (status & IRQF_SAMPLE_RANDOM)
1da177e4 LT	308	add_interrupt_randomness(irq);
	309	local_irq_disable();
	310
	311	return retval;
	312	}
	313
af8c65b5	314	#ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
8d28bc75 IM	315	/**
	316	* __do_IRQ - original all in one highlevel IRQ handler
	317	* @irq: the interrupt number
8d28bc75 IM	318	*
8d28bc75 IM	319	* __do_IRQ handles all normal device IRQ's (the special
1da177e4 LT	320	* SMP cross-CPU interrupts have their own specific
1da177e4 LT	321	* handlers).
8d28bc75 IM	322	*
	323	* This is the original x86 implementation which is used for every
	324	* interrupt type.
1da177e4	325	*/
7ad5b3a5	326	unsigned int __do_IRQ(unsigned int irq)
1da177e4	327	{
08678b08	328	struct irq_desc *desc = irq_to_desc(irq);
06fcb0c6	329	struct irqaction *action;
1da177e4 LT	330	unsigned int status;
1da177e4 LT	331
d6c88a50 TG	332	kstat_incr_irqs_this_cpu(irq, desc);
d6c88a50 TG	333
f26fdd59	334	if (CHECK_IRQ_PER_CPU(desc->status)) {
1da177e4 LT	335	irqreturn_t action_ret;
	336
	337	/*
	338	* No locking required for CPU-local interrupts:
	339	*/
d1bef4ed IM	340	if (desc->chip->ack)
d1bef4ed IM	341	desc->chip->ack(irq);
c642b839 RA	342	if (likely(!(desc->status & IRQ_DISABLED))) {
	343	action_ret = handle_IRQ_event(irq, desc->action);
	344	if (!noirqdebug)
	345	note_interrupt(irq, desc, action_ret);
	346	}
d1bef4ed	347	desc->chip->end(irq);
1da177e4 LT	348	return 1;
	349	}
	350
	351	spin_lock(&desc->lock);
d1bef4ed IM	352	if (desc->chip->ack)
d1bef4ed IM	353	desc->chip->ack(irq);
1da177e4 LT	354	/*
	355	* REPLAY is when Linux resends an IRQ that was dropped earlier
	356	* WAITING is used by probe to mark irqs that are being tested
	357	*/
	358	status = desc->status & ~(IRQ_REPLAY \| IRQ_WAITING);
	359	status \|= IRQ_PENDING; /* we _want_ to handle it */
	360
	361	/*
	362	* If the IRQ is disabled for whatever reason, we cannot
	363	* use the action we have.
	364	*/
	365	action = NULL;
	366	if (likely(!(status & (IRQ_DISABLED \| IRQ_INPROGRESS)))) {
	367	action = desc->action;
	368	status &= ~IRQ_PENDING; /* we commit to handling */
	369	status \|= IRQ_INPROGRESS; /* we are handling it */
	370	}
	371	desc->status = status;
	372
	373	/*
	374	* If there is no IRQ handler or it was disabled, exit early.
	375	* Since we set PENDING, if another processor is handling
	376	* a different instance of this same irq, the other processor
	377	* will take care of it.
	378	*/
	379	if (unlikely(!action))
	380	goto out;
	381
	382	/*
	383	* Edge triggered interrupts need to remember
	384	* pending events.
	385	* This applies to any hw interrupts that allow a second
	386	* instance of the same irq to arrive while we are in do_IRQ
	387	* or in the handler. But the code here only handles the _second_
	388	* instance of the irq, not the third or fourth. So it is mostly
	389	* useful for irq hardware that does not mask cleanly in an
	390	* SMP environment.
	391	*/
	392	for (;;) {
	393	irqreturn_t action_ret;
	394
	395	spin_unlock(&desc->lock);
	396
7d12e780	397	action_ret = handle_IRQ_event(irq, action);
1da177e4	398	if (!noirqdebug)
7d12e780	399	note_interrupt(irq, desc, action_ret);
b42172fc LT	400
b42172fc LT	401	spin_lock(&desc->lock);
1da177e4 LT	402	if (likely(!(desc->status & IRQ_PENDING)))
	403	break;
	404	desc->status &= ~IRQ_PENDING;
	405	}
	406	desc->status &= ~IRQ_INPROGRESS;
	407
	408	out:
	409	/*
	410	* The ->end() handler has to deal with interrupts which got
	411	* disabled while the handler was running.
	412	*/
d1bef4ed	413	desc->chip->end(irq);
1da177e4 LT	414	spin_unlock(&desc->lock);
	415
	416	return 1;
	417	}
af8c65b5	418	#endif
1da177e4	419
243c7621	420
08678b08	421	#ifdef CONFIG_TRACE_IRQFLAGS
243c7621 IM	422	void early_init_irq_lock_class(void)
243c7621 IM	423	{
0b8f1efa	424	#ifndef CONFIG_SPARSE_IRQ
10e58084	425	struct irq_desc *desc;
243c7621 IM	426	int i;
243c7621 IM	427
0b8f1efa YL	428	for_each_irq_desc(i, desc) {
	429	if (!desc)
	430	continue;
	431
10e58084	432	lockdep_set_class(&desc->lock, &irq_desc_lock_class);
0b8f1efa YL	433	}
	434	#endif
	435	}
	436	#endif
	437
	438	#ifdef CONFIG_SPARSE_IRQ
	439	unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
	440	{
	441	struct irq_desc *desc = irq_to_desc(irq);
	442	return desc->kstat_irqs[cpu];
243c7621	443	}
243c7621	444	#endif
0b8f1efa YL	445	EXPORT_SYMBOL(kstat_irqs_cpu);
0b8f1efa YL	446