[GitHub/mt8127/android_kernel_alcatel_ttab.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:
 */
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
};

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:
 */
DEFINE_SPINLOCK(sparse_irq_lock);

struct irq_desc *irq_desc_ptrs[NR_IRQS] __read_mostly;

static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
	[0 ... NR_IRQS_LEGACY-1] = {
		.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[NR_IRQS_LEGACY][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 /* !CONFIG_SPARSE_IRQ */

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
	}
};

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

struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
{
	return irq_to_desc(irq);
}
#endif /* !CONFIG_SPARSE_IRQ */

/*
 * 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);
			/* get new one */
			desc = irq_remap_to_desc(irq, desc);
		}
		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);
		desc = irq_remap_to_desc(irq, desc);
	}
	/*
	 * 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

void early_init_irq_lock_class(void)
{
	struct irq_desc *desc;
	int i;

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

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

#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	*/
48a1b10a	26	struct lock_class_key irq_desc_lock_class;
0b8f1efa	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
48a1b10a	76	void init_kstat_irqs(struct irq_desc *desc, int cpu, int nr)
0b8f1efa YL	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	*/
48a1b10a	116	DEFINE_SPINLOCK(sparse_irq_lock);
0b8f1efa YL	117
	118	struct irq_desc *irq_desc_ptrs[NR_IRQS] __read_mostly;
	119
99d093d1 YL	120	static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
99d093d1 YL	121	[0 ... NR_IRQS_LEGACY-1] = {
0b8f1efa YL	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 ...*/
99d093d1	135	static unsigned int kstat_irqs_legacy[NR_IRQS_LEGACY][NR_CPUS];
0b8f1efa YL	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
f9af0e70	206	#else /* !CONFIG_SPARSE_IRQ */
0b8f1efa	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
f9af0e70 KM	221	struct irq_desc *irq_to_desc(unsigned int irq)
	222	{
	223	return (irq < NR_IRQS) ? irq_desc + irq : NULL;
	224	}
	225
	226	struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
	227	{
	228	return irq_to_desc(irq);
	229	}
	230	#endif /* !CONFIG_SPARSE_IRQ */
0b8f1efa	231
1da177e4	232	/*
77a5afec IM	233	* What should we do if we get a hw irq event on an illegal vector?
77a5afec IM	234	* Each architecture has to answer this themself.
1da177e4	235	*/
77a5afec	236	static void ack_bad(unsigned int irq)
1da177e4	237	{
d3c60047	238	struct irq_desc *desc = irq_to_desc(irq);
08678b08	239
08678b08	240	print_irq_desc(irq, desc);
1da177e4 LT	241	ack_bad_irq(irq);
	242	}
	243
77a5afec IM	244	/*
	245	* NOP functions
	246	*/
	247	static void noop(unsigned int irq)
	248	{
	249	}
	250
	251	static unsigned int noop_ret(unsigned int irq)
	252	{
	253	return 0;
	254	}
	255
	256	/*
	257	* Generic no controller implementation
	258	*/
f1c2662c IM	259	struct irq_chip no_irq_chip = {
f1c2662c IM	260	.name = "none",
77a5afec IM	261	.startup = noop_ret,
	262	.shutdown = noop,
	263	.enable = noop,
	264	.disable = noop,
	265	.ack = ack_bad,
	266	.end = noop,
1da177e4 LT	267	};
1da177e4 LT	268
f8b5473f TG	269	/*
	270	* Generic dummy implementation which can be used for
	271	* real dumb interrupt sources
	272	*/
	273	struct irq_chip dummy_irq_chip = {
	274	.name = "dummy",
	275	.startup = noop_ret,
	276	.shutdown = noop,
	277	.enable = noop,
	278	.disable = noop,
	279	.ack = noop,
	280	.mask = noop,
	281	.unmask = noop,
	282	.end = noop,
	283	};
	284
1da177e4 LT	285	/*
	286	* Special, empty irq handler:
	287	*/
7d12e780	288	irqreturn_t no_action(int cpl, void *dev_id)
1da177e4 LT	289	{
	290	return IRQ_NONE;
	291	}
	292
8d28bc75 IM	293	/**
	294	* handle_IRQ_event - irq action chain handler
	295	* @irq: the interrupt number
8d28bc75 IM	296	* @action: the interrupt action chain for this irq
	297	*
	298	* Handles the action chain of an irq event
1da177e4	299	*/
7d12e780	300	irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
1da177e4	301	{
908dcecd JB	302	irqreturn_t ret, retval = IRQ_NONE;
908dcecd JB	303	unsigned int status = 0;
1da177e4	304
3cca53b0	305	if (!(action->flags & IRQF_DISABLED))
366c7f55	306	local_irq_enable_in_hardirq();
1da177e4 LT	307
1da177e4 LT	308	do {
7d12e780	309	ret = action->handler(irq, action->dev_id);
1da177e4 LT	310	if (ret == IRQ_HANDLED)
	311	status \|= action->flags;
	312	retval \|= ret;
	313	action = action->next;
	314	} while (action);
	315
3cca53b0	316	if (status & IRQF_SAMPLE_RANDOM)
1da177e4 LT	317	add_interrupt_randomness(irq);
	318	local_irq_disable();
	319
	320	return retval;
	321	}
	322
af8c65b5	323	#ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
8d28bc75 IM	324	/**
	325	* __do_IRQ - original all in one highlevel IRQ handler
	326	* @irq: the interrupt number
8d28bc75 IM	327	*
8d28bc75 IM	328	* __do_IRQ handles all normal device IRQ's (the special
1da177e4 LT	329	* SMP cross-CPU interrupts have their own specific
1da177e4 LT	330	* handlers).
8d28bc75 IM	331	*
	332	* This is the original x86 implementation which is used for every
	333	* interrupt type.
1da177e4	334	*/
7ad5b3a5	335	unsigned int __do_IRQ(unsigned int irq)
1da177e4	336	{
08678b08	337	struct irq_desc *desc = irq_to_desc(irq);
06fcb0c6	338	struct irqaction *action;
1da177e4 LT	339	unsigned int status;
1da177e4 LT	340
d6c88a50 TG	341	kstat_incr_irqs_this_cpu(irq, desc);
d6c88a50 TG	342
f26fdd59	343	if (CHECK_IRQ_PER_CPU(desc->status)) {
1da177e4 LT	344	irqreturn_t action_ret;
	345
	346	/*
	347	* No locking required for CPU-local interrupts:
	348	*/
48a1b10a	349	if (desc->chip->ack) {
d1bef4ed	350	desc->chip->ack(irq);
48a1b10a YL	351	/* get new one */
	352	desc = irq_remap_to_desc(irq, desc);
	353	}
c642b839 RA	354	if (likely(!(desc->status & IRQ_DISABLED))) {
	355	action_ret = handle_IRQ_event(irq, desc->action);
	356	if (!noirqdebug)
	357	note_interrupt(irq, desc, action_ret);
	358	}
d1bef4ed	359	desc->chip->end(irq);
1da177e4 LT	360	return 1;
	361	}
	362
	363	spin_lock(&desc->lock);
48a1b10a	364	if (desc->chip->ack) {
d1bef4ed	365	desc->chip->ack(irq);
48a1b10a YL	366	desc = irq_remap_to_desc(irq, desc);
48a1b10a YL	367	}
1da177e4 LT	368	/*
	369	* REPLAY is when Linux resends an IRQ that was dropped earlier
	370	* WAITING is used by probe to mark irqs that are being tested
	371	*/
	372	status = desc->status & ~(IRQ_REPLAY \| IRQ_WAITING);
	373	status \|= IRQ_PENDING; /* we _want_ to handle it */
	374
	375	/*
	376	* If the IRQ is disabled for whatever reason, we cannot
	377	* use the action we have.
	378	*/
	379	action = NULL;
	380	if (likely(!(status & (IRQ_DISABLED \| IRQ_INPROGRESS)))) {
	381	action = desc->action;
	382	status &= ~IRQ_PENDING; /* we commit to handling */
	383	status \|= IRQ_INPROGRESS; /* we are handling it */
	384	}
	385	desc->status = status;
	386
	387	/*
	388	* If there is no IRQ handler or it was disabled, exit early.
	389	* Since we set PENDING, if another processor is handling
	390	* a different instance of this same irq, the other processor
	391	* will take care of it.
	392	*/
	393	if (unlikely(!action))
	394	goto out;
	395
	396	/*
	397	* Edge triggered interrupts need to remember
	398	* pending events.
	399	* This applies to any hw interrupts that allow a second
	400	* instance of the same irq to arrive while we are in do_IRQ
	401	* or in the handler. But the code here only handles the _second_
	402	* instance of the irq, not the third or fourth. So it is mostly
	403	* useful for irq hardware that does not mask cleanly in an
	404	* SMP environment.
	405	*/
	406	for (;;) {
	407	irqreturn_t action_ret;
	408
	409	spin_unlock(&desc->lock);
	410
7d12e780	411	action_ret = handle_IRQ_event(irq, action);
1da177e4	412	if (!noirqdebug)
7d12e780	413	note_interrupt(irq, desc, action_ret);
b42172fc LT	414
b42172fc LT	415	spin_lock(&desc->lock);
1da177e4 LT	416	if (likely(!(desc->status & IRQ_PENDING)))
	417	break;
	418	desc->status &= ~IRQ_PENDING;
	419	}
	420	desc->status &= ~IRQ_INPROGRESS;
	421
	422	out:
	423	/*
	424	* The ->end() handler has to deal with interrupts which got
	425	* disabled while the handler was running.
	426	*/
d1bef4ed	427	desc->chip->end(irq);
1da177e4 LT	428	spin_unlock(&desc->lock);
	429
	430	return 1;
	431	}
af8c65b5	432	#endif
1da177e4	433
243c7621 IM	434	void early_init_irq_lock_class(void)
243c7621 IM	435	{
10e58084	436	struct irq_desc *desc;
243c7621 IM	437	int i;
243c7621 IM	438
0b8f1efa YL	439	for_each_irq_desc(i, desc) {
	440	if (!desc)
	441	continue;
	442
10e58084	443	lockdep_set_class(&desc->lock, &irq_desc_lock_class);
0b8f1efa	444	}
0b8f1efa	445	}
0b8f1efa YL	446
	447	#ifdef CONFIG_SPARSE_IRQ
	448	unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
	449	{
	450	struct irq_desc *desc = irq_to_desc(irq);
	451	return desc->kstat_irqs[cpu];
243c7621	452	}
243c7621	453	#endif
0b8f1efa YL	454	EXPORT_SYMBOL(kstat_irqs_cpu);
0b8f1efa YL	455