[net-next-2.6.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;

	raw_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;
		raw_spin_unlock(&desc->lock);
		return ok;
	}
	/* Honour the normal IRQ locking */
	desc->status |= IRQ_INPROGRESS;
	action = desc->action;
	raw_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 */
	raw_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;
		raw_spin_unlock(&desc->lock);
		handle_IRQ_event(irq, action);
		raw_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);
	raw_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;

		local_irq_disable();
		try_one_irq(i, desc);
		local_irq_enable();
	}

	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 counter 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);

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
239007b8	31	raw_spin_lock(&desc->lock);
f84dbb91 EB	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;
239007b8	40	raw_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;
239007b8	46	raw_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 */
239007b8	59	raw_spin_lock(&desc->lock);
f84dbb91	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;
239007b8	71	raw_spin_unlock(&desc->lock);
f84dbb91	72	handle_IRQ_event(irq, action);
239007b8	73	raw_spin_lock(&desc->lock);
f84dbb91 EB	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);
239007b8	83	raw_spin_unlock(&desc->lock);
f84dbb91 EB	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
663e6959	107	static void poll_spurious_irqs(unsigned long dummy)
f84dbb91	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
e7e7e0c0	124	local_irq_disable();
f84dbb91	125	try_one_irq(i, desc);
e7e7e0c0	126	local_irq_enable();
f84dbb91 EB	127	}
f84dbb91 EB	128
d3c60047 TG	129	mod_timer(&poll_spurious_irq_timer,
d3c60047 TG	130	jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
f84dbb91 EB	131	}
f84dbb91 EB	132
1da177e4 LT	133	/*
	134	* If 99,900 of the previous 100,000 interrupts have not been handled
	135	* then assume that the IRQ is stuck in some manner. Drop a diagnostic
	136	* and try to turn the IRQ off.
	137	*
	138	* (The other 100-of-100,000 interrupts may have been a correctly
	139	* functioning device sharing an IRQ with the failing one)
	140	*
	141	* Called under desc->lock
	142	*/
	143
	144	static void
34ffdb72 IM	145	__report_bad_irq(unsigned int irq, struct irq_desc *desc,
34ffdb72 IM	146	irqreturn_t action_ret)
1da177e4 LT	147	{
	148	struct irqaction *action;
	149
	150	if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
	151	printk(KERN_ERR "irq event %d: bogus return value %x\n",
	152	irq, action_ret);
	153	} else {
200803df AC	154	printk(KERN_ERR "irq %d: nobody cared (try booting with "
200803df AC	155	"the \"irqpoll\" option)\n", irq);
1da177e4 LT	156	}
	157	dump_stack();
	158	printk(KERN_ERR "handlers:\n");
06fcb0c6	159
1da177e4 LT	160	action = desc->action;
	161	while (action) {
	162	printk(KERN_ERR "[<%p>]", action->handler);
	163	print_symbol(" (%s)",
	164	(unsigned long)action->handler);
	165	printk("\n");
	166	action = action->next;
	167	}
	168	}
	169
06fcb0c6	170	static void
34ffdb72	171	report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
1da177e4 LT	172	{
	173	static int count = 100;
	174
	175	if (count > 0) {
	176	count--;
	177	__report_bad_irq(irq, desc, action_ret);
	178	}
	179	}
	180
d3c60047 TG	181	static inline int
	182	try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
	183	irqreturn_t action_ret)
92ea7727 LT	184	{
	185	struct irqaction *action;
	186
	187	if (!irqfixup)
	188	return 0;
	189
	190	/* We didn't actually handle the IRQ - see if it was misrouted? */
	191	if (action_ret == IRQ_NONE)
	192	return 1;
	193
	194	/*
	195	* But for 'irqfixup == 2' we also do it for handled interrupts if
	196	* they are marked as IRQF_IRQPOLL (or for irq zero, which is the
	197	* traditional PC timer interrupt.. Legacy)
	198	*/
	199	if (irqfixup < 2)
	200	return 0;
	201
	202	if (!irq)
	203	return 1;
	204
	205	/*
	206	* Since we don't get the descriptor lock, "action" can
	207	* change under us. We don't really care, but we don't
	208	* want to follow a NULL pointer. So tell the compiler to
	209	* just load it once by using a barrier.
	210	*/
	211	action = desc->action;
	212	barrier();
	213	return action && (action->flags & IRQF_IRQPOLL);
	214	}
	215
34ffdb72	216	void note_interrupt(unsigned int irq, struct irq_desc *desc,
7d12e780	217	irqreturn_t action_ret)
1da177e4	218	{
83d4e6e7	219	if (unlikely(action_ret != IRQ_HANDLED)) {
4f27c00b AC	220	/*
	221	* If we are seeing only the odd spurious IRQ caused by
	222	* bus asynchronicity then don't eventually trigger an error,
fbfecd37	223	* otherwise the counter becomes a doomsday timer for otherwise
4f27c00b AC	224	* working systems
4f27c00b AC	225	*/
188fd89d	226	if (time_after(jiffies, desc->last_unhandled + HZ/10))
4f27c00b AC	227	desc->irqs_unhandled = 1;
	228	else
	229	desc->irqs_unhandled++;
	230	desc->last_unhandled = jiffies;
83d4e6e7	231	if (unlikely(action_ret != IRQ_NONE))
1da177e4 LT	232	report_bad_irq(irq, desc, action_ret);
	233	}
	234
92ea7727 LT	235	if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
	236	int ok = misrouted_irq(irq);
	237	if (action_ret == IRQ_NONE)
	238	desc->irqs_unhandled -= ok;
200803df AC	239	}
200803df AC	240
1da177e4	241	desc->irq_count++;
83d4e6e7	242	if (likely(desc->irq_count < 100000))
1da177e4 LT	243	return;
	244
	245	desc->irq_count = 0;
83d4e6e7	246	if (unlikely(desc->irqs_unhandled > 99900)) {
1da177e4 LT	247	/*
	248	* The interrupt is stuck
	249	*/
	250	__report_bad_irq(irq, desc, action_ret);
	251	/*
	252	* Now kill the IRQ
	253	*/
	254	printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
1adb0850 TG	255	desc->status \|= IRQ_DISABLED \| IRQ_SPURIOUS_DISABLED;
1adb0850 TG	256	desc->depth++;
d1bef4ed	257	desc->chip->disable(irq);
f84dbb91	258
d3c60047 TG	259	mod_timer(&poll_spurious_irq_timer,
d3c60047 TG	260	jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
1da177e4 LT	261	}
	262	desc->irqs_unhandled = 0;
	263	}
	264
83d4e6e7	265	int noirqdebug __read_mostly;
1da177e4	266
343cde51	267	int noirqdebug_setup(char *str)
1da177e4 LT	268	{
	269	noirqdebug = 1;
	270	printk(KERN_INFO "IRQ lockup detection disabled\n");
06fcb0c6	271
1da177e4 LT	272	return 1;
	273	}
	274
	275	__setup("noirqdebug", noirqdebug_setup);
9e094c17 AK	276	module_param(noirqdebug, bool, 0644);
9e094c17 AK	277	MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
1da177e4	278
200803df AC	279	static int __init irqfixup_setup(char *str)
	280	{
	281	irqfixup = 1;
	282	printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
	283	printk(KERN_WARNING "This may impact system performance.\n");
06fcb0c6	284
200803df AC	285	return 1;
	286	}
	287
	288	__setup("irqfixup", irqfixup_setup);
9e094c17	289	module_param(irqfixup, int, 0644);
200803df AC	290
	291	static int __init irqpoll_setup(char *str)
	292	{
	293	irqfixup = 2;
	294	printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
	295	"enabled\n");
	296	printk(KERN_WARNING "This may significantly impact system "
	297	"performance\n");
	298	return 1;
	299	}
	300
	301	__setup("irqpoll", irqpoll_setup);