[deliverable/linux.git] / kernel / irq / spurious.c

/*
 * linux/kernel/irq/spurious.c
 *
 * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
 *
 * This file contains spurious interrupt handling.
 */

#include <linux/jiffies.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/interrupt.h>
#include <linux/moduleparam.h>
#include <linux/timer.h>

static int irqfixup __read_mostly;

#define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10)
static void poll_spurious_irqs(unsigned long dummy);
static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs, 0, 0);

/*
 * Recovery handler for misrouted interrupts.
 */
static int try_one_irq(int irq, struct irq_desc *desc)
{
	struct irqaction *action;
	int ok = 0;
	int work = 0;	/* Did we do work for a real IRQ */

	spin_lock(&desc->lock);
	/* Already running on another processor */
	if (desc->status & IRQ_INPROGRESS) {
		/*
		 * Already running: If it is shared get the other
		 * CPU to go looking for our mystery interrupt too
		 */
		if (desc->action && (desc->action->flags & IRQF_SHARED))
			desc->status |= IRQ_PENDING;
		spin_unlock(&desc->lock);
		return ok;
	}
	/* Honour the normal IRQ locking */
	desc->status |= IRQ_INPROGRESS;
	action = desc->action;
	spin_unlock(&desc->lock);

	while (action) {
		/* Only shared IRQ handlers are safe to call */
		if (action->flags & IRQF_SHARED) {
			if (action->handler(irq, action->dev_id) ==
				IRQ_HANDLED)
				ok = 1;
		}
		action = action->next;
	}
	local_irq_disable();
	/* Now clean up the flags */
	spin_lock(&desc->lock);
	action = desc->action;

	/*
	 * While we were looking for a fixup someone queued a real
	 * IRQ clashing with our walk:
	 */
	while ((desc->status & IRQ_PENDING) && action) {
		/*
		 * Perform real IRQ processing for the IRQ we deferred
		 */
		work = 1;
		spin_unlock(&desc->lock);
		handle_IRQ_event(irq, action);
		spin_lock(&desc->lock);
		desc->status &= ~IRQ_PENDING;
	}
	desc->status &= ~IRQ_INPROGRESS;
	/*
	 * If we did actual work for the real IRQ line we must let the
	 * IRQ controller clean up too
	 */
	if (work && desc->chip && desc->chip->end)
		desc->chip->end(irq);
	spin_unlock(&desc->lock);

	return ok;
}

static int misrouted_irq(int irq)
{
	int i;
	int ok = 0;

	for (i = 1; i < nr_irqs; i++) {
		struct irq_desc *desc;

		if (i == irq)	/* Already tried */
			continue;

		desc = irq_to_desc(i);
		if (try_one_irq(i, desc))
			ok = 1;
	}
	/* So the caller can adjust the irq error counts */
	return ok;
}

static void poll_spurious_irqs(unsigned long dummy)
{
	int i;
	for (i = 1; i < nr_irqs; i++) {
		struct irq_desc *desc = irq_to_desc(i);
		unsigned int status;

		/* Racy but it doesn't matter */
		status = desc->status;
		barrier();
		if (!(status & IRQ_SPURIOUS_DISABLED))
			continue;

		try_one_irq(i, desc);
	}

	mod_timer(&poll_spurious_irq_timer, jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
}

/*
 * If 99,900 of the previous 100,000 interrupts have not been handled
 * then assume that the IRQ is stuck in some manner. Drop a diagnostic
 * and try to turn the IRQ off.
 *
 * (The other 100-of-100,000 interrupts may have been a correctly
 *  functioning device sharing an IRQ with the failing one)
 *
 * Called under desc->lock
 */

static void
__report_bad_irq(unsigned int irq, struct irq_desc *desc,
		 irqreturn_t action_ret)
{
	struct irqaction *action;

	if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
		printk(KERN_ERR "irq event %d: bogus return value %x\n",
				irq, action_ret);
	} else {
		printk(KERN_ERR "irq %d: nobody cared (try booting with "
				"the \"irqpoll\" option)\n", irq);
	}
	dump_stack();
	printk(KERN_ERR "handlers:\n");

	action = desc->action;
	while (action) {
		printk(KERN_ERR "[<%p>]", action->handler);
		print_symbol(" (%s)",
			(unsigned long)action->handler);
		printk("\n");
		action = action->next;
	}
}

static void
report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
{
	static int count = 100;

	if (count > 0) {
		count--;
		__report_bad_irq(irq, desc, action_ret);
	}
}

static inline int try_misrouted_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
{
	struct irqaction *action;

	if (!irqfixup)
		return 0;

	/* We didn't actually handle the IRQ - see if it was misrouted? */
	if (action_ret == IRQ_NONE)
		return 1;

	/*
	 * But for 'irqfixup == 2' we also do it for handled interrupts if
	 * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
	 * traditional PC timer interrupt.. Legacy)
	 */
	if (irqfixup < 2)
		return 0;

	if (!irq)
		return 1;

	/*
	 * Since we don't get the descriptor lock, "action" can
	 * change under us.  We don't really care, but we don't
	 * want to follow a NULL pointer. So tell the compiler to
	 * just load it once by using a barrier.
	 */
	action = desc->action;
	barrier();
	return action && (action->flags & IRQF_IRQPOLL);
}

void note_interrupt(unsigned int irq, struct irq_desc *desc,
		    irqreturn_t action_ret)
{
	if (unlikely(action_ret != IRQ_HANDLED)) {
		/*
		 * If we are seeing only the odd spurious IRQ caused by
		 * bus asynchronicity then don't eventually trigger an error,
		 * otherwise the couter becomes a doomsday timer for otherwise
		 * working systems
		 */
		if (time_after(jiffies, desc->last_unhandled + HZ/10))
			desc->irqs_unhandled = 1;
		else
			desc->irqs_unhandled++;
		desc->last_unhandled = jiffies;
		if (unlikely(action_ret != IRQ_NONE))
			report_bad_irq(irq, desc, action_ret);
	}

	if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
		int ok = misrouted_irq(irq);
		if (action_ret == IRQ_NONE)
			desc->irqs_unhandled -= ok;
	}

	desc->irq_count++;
	if (likely(desc->irq_count < 100000))
		return;

	desc->irq_count = 0;
	if (unlikely(desc->irqs_unhandled > 99900)) {
		/*
		 * The interrupt is stuck
		 */
		__report_bad_irq(irq, desc, action_ret);
		/*
		 * Now kill the IRQ
		 */
		printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
		desc->status |= IRQ_DISABLED | IRQ_SPURIOUS_DISABLED;
		desc->depth++;
		desc->chip->disable(irq);

		mod_timer(&poll_spurious_irq_timer, jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
	}
	desc->irqs_unhandled = 0;
}

int noirqdebug __read_mostly;

int noirqdebug_setup(char *str)
{
	noirqdebug = 1;
	printk(KERN_INFO "IRQ lockup detection disabled\n");

	return 1;
}

__setup("noirqdebug", noirqdebug_setup);
module_param(noirqdebug, bool, 0644);
MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");

static int __init irqfixup_setup(char *str)
{
	irqfixup = 1;
	printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
	printk(KERN_WARNING "This may impact system performance.\n");

	return 1;
}

__setup("irqfixup", irqfixup_setup);
module_param(irqfixup, int, 0644);
MODULE_PARM_DESC("irqfixup", "0: No fixup, 1: irqfixup mode 2: irqpoll mode");

static int __init irqpoll_setup(char *str)
{
	irqfixup = 2;
	printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
				"enabled\n");
	printk(KERN_WARNING "This may significantly impact system "
				"performance\n");
	return 1;
}

__setup("irqpoll", irqpoll_setup);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/kernel/irq/spurious.c
	3	*
	4	* Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
	5	*
	6	* This file contains spurious interrupt handling.
	7	*/
	8
188fd89d	9	#include <linux/jiffies.h>
1da177e4 LT	10	#include <linux/irq.h>
	11	#include <linux/module.h>
	12	#include <linux/kallsyms.h>
	13	#include <linux/interrupt.h>
9e094c17	14	#include <linux/moduleparam.h>
f84dbb91	15	#include <linux/timer.h>
1da177e4	16
83d4e6e7	17	static int irqfixup __read_mostly;
200803df	18
f84dbb91 EB	19	#define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10)
	20	static void poll_spurious_irqs(unsigned long dummy);
	21	static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs, 0, 0);
	22
200803df AC	23	/*
	24	* Recovery handler for misrouted interrupts.
	25	*/
f84dbb91	26	static int try_one_irq(int irq, struct irq_desc *desc)
200803df	27	{
f84dbb91	28	struct irqaction *action;
200803df AC	29	int ok = 0;
	30	int work = 0; /* Did we do work for a real IRQ */
	31
f84dbb91 EB	32	spin_lock(&desc->lock);
	33	/* Already running on another processor */
	34	if (desc->status & IRQ_INPROGRESS) {
	35	/*
	36	* Already running: If it is shared get the other
	37	* CPU to go looking for our mystery interrupt too
	38	*/
	39	if (desc->action && (desc->action->flags & IRQF_SHARED))
	40	desc->status \|= IRQ_PENDING;
200803df	41	spin_unlock(&desc->lock);
f84dbb91 EB	42	return ok;
	43	}
	44	/* Honour the normal IRQ locking */
	45	desc->status \|= IRQ_INPROGRESS;
	46	action = desc->action;
	47	spin_unlock(&desc->lock);
06fcb0c6	48
f84dbb91 EB	49	while (action) {
	50	/* Only shared IRQ handlers are safe to call */
	51	if (action->flags & IRQF_SHARED) {
	52	if (action->handler(irq, action->dev_id) ==
	53	IRQ_HANDLED)
	54	ok = 1;
200803df	55	}
f84dbb91 EB	56	action = action->next;
	57	}
	58	local_irq_disable();
	59	/* Now clean up the flags */
	60	spin_lock(&desc->lock);
	61	action = desc->action;
200803df	62
f84dbb91 EB	63	/*
	64	* While we were looking for a fixup someone queued a real
	65	* IRQ clashing with our walk:
	66	*/
	67	while ((desc->status & IRQ_PENDING) && action) {
200803df	68	/*
f84dbb91	69	* Perform real IRQ processing for the IRQ we deferred
200803df	70	*/
f84dbb91	71	work = 1;
200803df	72	spin_unlock(&desc->lock);
f84dbb91 EB	73	handle_IRQ_event(irq, action);
	74	spin_lock(&desc->lock);
	75	desc->status &= ~IRQ_PENDING;
	76	}
	77	desc->status &= ~IRQ_INPROGRESS;
	78	/*
	79	* If we did actual work for the real IRQ line we must let the
	80	* IRQ controller clean up too
	81	*/
	82	if (work && desc->chip && desc->chip->end)
	83	desc->chip->end(irq);
	84	spin_unlock(&desc->lock);
	85
	86	return ok;
	87	}
	88
	89	static int misrouted_irq(int irq)
	90	{
	91	int i;
	92	int ok = 0;
	93
85c0f909	94	for (i = 1; i < nr_irqs; i++) {
08678b08	95	struct irq_desc *desc;
f84dbb91 EB	96
	97	if (i == irq) /* Already tried */
	98	continue;
	99
08678b08	100	desc = irq_to_desc(i);
f84dbb91 EB	101	if (try_one_irq(i, desc))
f84dbb91 EB	102	ok = 1;
200803df AC	103	}
	104	/* So the caller can adjust the irq error counts */
	105	return ok;
	106	}
	107
f84dbb91 EB	108	static void poll_spurious_irqs(unsigned long dummy)
	109	{
	110	int i;
85c0f909	111	for (i = 1; i < nr_irqs; i++) {
08678b08	112	struct irq_desc *desc = irq_to_desc(i);
f84dbb91 EB	113	unsigned int status;
	114
	115	/* Racy but it doesn't matter */
	116	status = desc->status;
	117	barrier();
	118	if (!(status & IRQ_SPURIOUS_DISABLED))
	119	continue;
	120
	121	try_one_irq(i, desc);
	122	}
	123
	124	mod_timer(&poll_spurious_irq_timer, jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
	125	}
	126
1da177e4 LT	127	/*
	128	* If 99,900 of the previous 100,000 interrupts have not been handled
	129	* then assume that the IRQ is stuck in some manner. Drop a diagnostic
	130	* and try to turn the IRQ off.
	131	*
	132	* (The other 100-of-100,000 interrupts may have been a correctly
	133	* functioning device sharing an IRQ with the failing one)
	134	*
	135	* Called under desc->lock
	136	*/
	137
	138	static void
34ffdb72 IM	139	__report_bad_irq(unsigned int irq, struct irq_desc *desc,
34ffdb72 IM	140	irqreturn_t action_ret)
1da177e4 LT	141	{
	142	struct irqaction *action;
	143
	144	if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
	145	printk(KERN_ERR "irq event %d: bogus return value %x\n",
	146	irq, action_ret);
	147	} else {
200803df AC	148	printk(KERN_ERR "irq %d: nobody cared (try booting with "
200803df AC	149	"the \"irqpoll\" option)\n", irq);
1da177e4 LT	150	}
	151	dump_stack();
	152	printk(KERN_ERR "handlers:\n");
06fcb0c6	153
1da177e4 LT	154	action = desc->action;
	155	while (action) {
	156	printk(KERN_ERR "[<%p>]", action->handler);
	157	print_symbol(" (%s)",
	158	(unsigned long)action->handler);
	159	printk("\n");
	160	action = action->next;
	161	}
	162	}
	163
06fcb0c6	164	static void
34ffdb72	165	report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
1da177e4 LT	166	{
	167	static int count = 100;
	168
	169	if (count > 0) {
	170	count--;
	171	__report_bad_irq(irq, desc, action_ret);
	172	}
	173	}
	174
92ea7727 LT	175	static inline int try_misrouted_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
	176	{
	177	struct irqaction *action;
	178
	179	if (!irqfixup)
	180	return 0;
	181
	182	/* We didn't actually handle the IRQ - see if it was misrouted? */
	183	if (action_ret == IRQ_NONE)
	184	return 1;
	185
	186	/*
	187	* But for 'irqfixup == 2' we also do it for handled interrupts if
	188	* they are marked as IRQF_IRQPOLL (or for irq zero, which is the
	189	* traditional PC timer interrupt.. Legacy)
	190	*/
	191	if (irqfixup < 2)
	192	return 0;
	193
	194	if (!irq)
	195	return 1;
	196
	197	/*
	198	* Since we don't get the descriptor lock, "action" can
	199	* change under us. We don't really care, but we don't
	200	* want to follow a NULL pointer. So tell the compiler to
	201	* just load it once by using a barrier.
	202	*/
	203	action = desc->action;
	204	barrier();
	205	return action && (action->flags & IRQF_IRQPOLL);
	206	}
	207
34ffdb72	208	void note_interrupt(unsigned int irq, struct irq_desc *desc,
7d12e780	209	irqreturn_t action_ret)
1da177e4	210	{
83d4e6e7	211	if (unlikely(action_ret != IRQ_HANDLED)) {
4f27c00b AC	212	/*
	213	* If we are seeing only the odd spurious IRQ caused by
	214	* bus asynchronicity then don't eventually trigger an error,
	215	* otherwise the couter becomes a doomsday timer for otherwise
	216	* working systems
	217	*/
188fd89d	218	if (time_after(jiffies, desc->last_unhandled + HZ/10))
4f27c00b AC	219	desc->irqs_unhandled = 1;
	220	else
	221	desc->irqs_unhandled++;
	222	desc->last_unhandled = jiffies;
83d4e6e7	223	if (unlikely(action_ret != IRQ_NONE))
1da177e4 LT	224	report_bad_irq(irq, desc, action_ret);
	225	}
	226
92ea7727 LT	227	if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
	228	int ok = misrouted_irq(irq);
	229	if (action_ret == IRQ_NONE)
	230	desc->irqs_unhandled -= ok;
200803df AC	231	}
200803df AC	232
1da177e4	233	desc->irq_count++;
83d4e6e7	234	if (likely(desc->irq_count < 100000))
1da177e4 LT	235	return;
	236
	237	desc->irq_count = 0;
83d4e6e7	238	if (unlikely(desc->irqs_unhandled > 99900)) {
1da177e4 LT	239	/*
	240	* The interrupt is stuck
	241	*/
	242	__report_bad_irq(irq, desc, action_ret);
	243	/*
	244	* Now kill the IRQ
	245	*/
	246	printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
1adb0850 TG	247	desc->status \|= IRQ_DISABLED \| IRQ_SPURIOUS_DISABLED;
1adb0850 TG	248	desc->depth++;
d1bef4ed	249	desc->chip->disable(irq);
f84dbb91 EB	250
f84dbb91 EB	251	mod_timer(&poll_spurious_irq_timer, jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
1da177e4 LT	252	}
	253	desc->irqs_unhandled = 0;
	254	}
	255
83d4e6e7	256	int noirqdebug __read_mostly;
1da177e4	257
343cde51	258	int noirqdebug_setup(char *str)
1da177e4 LT	259	{
	260	noirqdebug = 1;
	261	printk(KERN_INFO "IRQ lockup detection disabled\n");
06fcb0c6	262
1da177e4 LT	263	return 1;
	264	}
	265
	266	__setup("noirqdebug", noirqdebug_setup);
9e094c17 AK	267	module_param(noirqdebug, bool, 0644);
9e094c17 AK	268	MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
1da177e4	269
200803df AC	270	static int __init irqfixup_setup(char *str)
	271	{
	272	irqfixup = 1;
	273	printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
	274	printk(KERN_WARNING "This may impact system performance.\n");
06fcb0c6	275
200803df AC	276	return 1;
	277	}
	278
	279	__setup("irqfixup", irqfixup_setup);
9e094c17 AK	280	module_param(irqfixup, int, 0644);
9e094c17 AK	281	MODULE_PARM_DESC("irqfixup", "0: No fixup, 1: irqfixup mode 2: irqpoll mode");
200803df AC	282
	283	static int __init irqpoll_setup(char *str)
	284	{
	285	irqfixup = 2;
	286	printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
	287	"enabled\n");
	288	printk(KERN_WARNING "This may significantly impact system "
	289	"performance\n");
	290	return 1;
	291	}
	292
	293	__setup("irqpoll", irqpoll_setup);