[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, work = 0;

	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)
{
	struct irq_desc *desc;
	int i, ok = 0;

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

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

		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)
{
	struct irq_desc *desc;
	int i;

	for_each_irq_desc(i, desc) {
		unsigned int status;

		if (!i)
			 continue;

		/* 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;
d3c60047	29	int ok = 0, work = 0;
200803df	30
f84dbb91 EB	31	spin_lock(&desc->lock);
	32	/* Already running on another processor */
	33	if (desc->status & IRQ_INPROGRESS) {
	34	/*
	35	* Already running: If it is shared get the other
	36	* CPU to go looking for our mystery interrupt too
	37	*/
	38	if (desc->action && (desc->action->flags & IRQF_SHARED))
	39	desc->status \|= IRQ_PENDING;
200803df	40	spin_unlock(&desc->lock);
f84dbb91 EB	41	return ok;
	42	}
	43	/* Honour the normal IRQ locking */
	44	desc->status \|= IRQ_INPROGRESS;
	45	action = desc->action;
	46	spin_unlock(&desc->lock);
06fcb0c6	47
f84dbb91 EB	48	while (action) {
	49	/* Only shared IRQ handlers are safe to call */
	50	if (action->flags & IRQF_SHARED) {
	51	if (action->handler(irq, action->dev_id) ==
	52	IRQ_HANDLED)
	53	ok = 1;
200803df	54	}
f84dbb91 EB	55	action = action->next;
	56	}
	57	local_irq_disable();
	58	/* Now clean up the flags */
	59	spin_lock(&desc->lock);
	60	action = desc->action;
200803df	61
f84dbb91 EB	62	/*
	63	* While we were looking for a fixup someone queued a real
	64	* IRQ clashing with our walk:
	65	*/
	66	while ((desc->status & IRQ_PENDING) && action) {
200803df	67	/*
f84dbb91	68	* Perform real IRQ processing for the IRQ we deferred
200803df	69	*/
f84dbb91	70	work = 1;
200803df	71	spin_unlock(&desc->lock);
f84dbb91 EB	72	handle_IRQ_event(irq, action);
	73	spin_lock(&desc->lock);
	74	desc->status &= ~IRQ_PENDING;
	75	}
	76	desc->status &= ~IRQ_INPROGRESS;
	77	/*
	78	* If we did actual work for the real IRQ line we must let the
	79	* IRQ controller clean up too
	80	*/
	81	if (work && desc->chip && desc->chip->end)
	82	desc->chip->end(irq);
	83	spin_unlock(&desc->lock);
	84
	85	return ok;
	86	}
	87
	88	static int misrouted_irq(int irq)
	89	{
e00585bb	90	struct irq_desc *desc;
d3c60047	91	int i, ok = 0;
f84dbb91	92
e00585bb YL	93	for_each_irq_desc(i, desc) {
	94	if (!i)
	95	continue;
f84dbb91 EB	96
	97	if (i == irq) /* Already tried */
	98	continue;
	99
	100	if (try_one_irq(i, desc))
	101	ok = 1;
200803df AC	102	}
	103	/* So the caller can adjust the irq error counts */
	104	return ok;
	105	}
	106
f84dbb91 EB	107	static void poll_spurious_irqs(unsigned long dummy)
f84dbb91 EB	108	{
e00585bb	109	struct irq_desc *desc;
d3c60047	110	int i;
e00585bb YL	111
e00585bb YL	112	for_each_irq_desc(i, desc) {
f84dbb91 EB	113	unsigned int status;
f84dbb91 EB	114
e00585bb YL	115	if (!i)
	116	continue;
	117
f84dbb91 EB	118	/* Racy but it doesn't matter */
	119	status = desc->status;
	120	barrier();
	121	if (!(status & IRQ_SPURIOUS_DISABLED))
	122	continue;
	123
	124	try_one_irq(i, desc);
	125	}
	126
d3c60047 TG	127	mod_timer(&poll_spurious_irq_timer,
d3c60047 TG	128	jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
f84dbb91 EB	129	}
f84dbb91 EB	130
1da177e4 LT	131	/*
	132	* If 99,900 of the previous 100,000 interrupts have not been handled
	133	* then assume that the IRQ is stuck in some manner. Drop a diagnostic
	134	* and try to turn the IRQ off.
	135	*
	136	* (The other 100-of-100,000 interrupts may have been a correctly
	137	* functioning device sharing an IRQ with the failing one)
	138	*
	139	* Called under desc->lock
	140	*/
	141
	142	static void
34ffdb72 IM	143	__report_bad_irq(unsigned int irq, struct irq_desc *desc,
34ffdb72 IM	144	irqreturn_t action_ret)
1da177e4 LT	145	{
	146	struct irqaction *action;
	147
	148	if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
	149	printk(KERN_ERR "irq event %d: bogus return value %x\n",
	150	irq, action_ret);
	151	} else {
200803df AC	152	printk(KERN_ERR "irq %d: nobody cared (try booting with "
200803df AC	153	"the \"irqpoll\" option)\n", irq);
1da177e4 LT	154	}
	155	dump_stack();
	156	printk(KERN_ERR "handlers:\n");
06fcb0c6	157
1da177e4 LT	158	action = desc->action;
	159	while (action) {
	160	printk(KERN_ERR "[<%p>]", action->handler);
	161	print_symbol(" (%s)",
	162	(unsigned long)action->handler);
	163	printk("\n");
	164	action = action->next;
	165	}
	166	}
	167
06fcb0c6	168	static void
34ffdb72	169	report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
1da177e4 LT	170	{
	171	static int count = 100;
	172
	173	if (count > 0) {
	174	count--;
	175	__report_bad_irq(irq, desc, action_ret);
	176	}
	177	}
	178
d3c60047 TG	179	static inline int
	180	try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
	181	irqreturn_t action_ret)
92ea7727 LT	182	{
	183	struct irqaction *action;
	184
	185	if (!irqfixup)
	186	return 0;
	187
	188	/* We didn't actually handle the IRQ - see if it was misrouted? */
	189	if (action_ret == IRQ_NONE)
	190	return 1;
	191
	192	/*
	193	* But for 'irqfixup == 2' we also do it for handled interrupts if
	194	* they are marked as IRQF_IRQPOLL (or for irq zero, which is the
	195	* traditional PC timer interrupt.. Legacy)
	196	*/
	197	if (irqfixup < 2)
	198	return 0;
	199
	200	if (!irq)
	201	return 1;
	202
	203	/*
	204	* Since we don't get the descriptor lock, "action" can
	205	* change under us. We don't really care, but we don't
	206	* want to follow a NULL pointer. So tell the compiler to
	207	* just load it once by using a barrier.
	208	*/
	209	action = desc->action;
	210	barrier();
	211	return action && (action->flags & IRQF_IRQPOLL);
	212	}
	213
34ffdb72	214	void note_interrupt(unsigned int irq, struct irq_desc *desc,
7d12e780	215	irqreturn_t action_ret)
1da177e4	216	{
83d4e6e7	217	if (unlikely(action_ret != IRQ_HANDLED)) {
4f27c00b AC	218	/*
	219	* If we are seeing only the odd spurious IRQ caused by
	220	* bus asynchronicity then don't eventually trigger an error,
	221	* otherwise the couter becomes a doomsday timer for otherwise
	222	* working systems
	223	*/
188fd89d	224	if (time_after(jiffies, desc->last_unhandled + HZ/10))
4f27c00b AC	225	desc->irqs_unhandled = 1;
	226	else
	227	desc->irqs_unhandled++;
	228	desc->last_unhandled = jiffies;
83d4e6e7	229	if (unlikely(action_ret != IRQ_NONE))
1da177e4 LT	230	report_bad_irq(irq, desc, action_ret);
	231	}
	232
92ea7727 LT	233	if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
	234	int ok = misrouted_irq(irq);
	235	if (action_ret == IRQ_NONE)
	236	desc->irqs_unhandled -= ok;
200803df AC	237	}
200803df AC	238
1da177e4	239	desc->irq_count++;
83d4e6e7	240	if (likely(desc->irq_count < 100000))
1da177e4 LT	241	return;
	242
	243	desc->irq_count = 0;
83d4e6e7	244	if (unlikely(desc->irqs_unhandled > 99900)) {
1da177e4 LT	245	/*
	246	* The interrupt is stuck
	247	*/
	248	__report_bad_irq(irq, desc, action_ret);
	249	/*
	250	* Now kill the IRQ
	251	*/
	252	printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
1adb0850 TG	253	desc->status \|= IRQ_DISABLED \| IRQ_SPURIOUS_DISABLED;
1adb0850 TG	254	desc->depth++;
d1bef4ed	255	desc->chip->disable(irq);
f84dbb91	256
d3c60047 TG	257	mod_timer(&poll_spurious_irq_timer,
d3c60047 TG	258	jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
1da177e4 LT	259	}
	260	desc->irqs_unhandled = 0;
	261	}
	262
83d4e6e7	263	int noirqdebug __read_mostly;
1da177e4	264
343cde51	265	int noirqdebug_setup(char *str)
1da177e4 LT	266	{
	267	noirqdebug = 1;
	268	printk(KERN_INFO "IRQ lockup detection disabled\n");
06fcb0c6	269
1da177e4 LT	270	return 1;
	271	}
	272
	273	__setup("noirqdebug", noirqdebug_setup);
9e094c17 AK	274	module_param(noirqdebug, bool, 0644);
9e094c17 AK	275	MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
1da177e4	276
200803df AC	277	static int __init irqfixup_setup(char *str)
	278	{
	279	irqfixup = 1;
	280	printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
	281	printk(KERN_WARNING "This may impact system performance.\n");
06fcb0c6	282
200803df AC	283	return 1;
	284	}
	285
	286	__setup("irqfixup", irqfixup_setup);
9e094c17	287	module_param(irqfixup, int, 0644);
e00585bb	288	MODULE_PARM_DESC("irqfixup", "0: No fixup, 1: irqfixup mode, 2: irqpoll mode");
200803df AC	289
	290	static int __init irqpoll_setup(char *str)
	291	{
	292	irqfixup = 2;
	293	printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
	294	"enabled\n");
	295	printk(KERN_WARNING "This may significantly impact system "
	296	"performance\n");
	297	return 1;
	298	}
	299
	300	__setup("irqpoll", irqpoll_setup);