[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>

#include "internals.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;
	}
	/*
	 * All handlers must agree on IRQF_SHARED, so we test just the
	 * first. Check for action->next as well.
	 */
	action = desc->action;
	if (!action || !(action->flags & IRQF_SHARED) || !action->next)
		goto out;

	/* Honour the normal IRQ locking */
	desc->status |= IRQ_INPROGRESS;
	do {
		work++;
		desc->status &= ~IRQ_PENDING;
		raw_spin_unlock(&desc->lock);
		if (handle_IRQ_event(irq, action) != IRQ_NONE)
			ok = 1;
		raw_spin_lock(&desc->lock);
		action = desc->action;
	}  while ((desc->status & IRQ_PENDING) && action);

	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 > 1)
		irq_end(irq, desc);

out:
	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)
 */
static void
__report_bad_irq(unsigned int irq, struct irq_desc *desc,
		 irqreturn_t action_ret)
{
	struct irqaction *action;
	unsigned long flags;

	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");

	/*
	 * We need to take desc->lock here. note_interrupt() is called
	 * w/o desc->lock held, but IRQ_PROGRESS set. We might race
	 * with something else removing an action. It's ok to take
	 * desc->lock here. See synchronize_irq().
	 */
	raw_spin_lock_irqsave(&desc->lock, flags);
	action = desc->action;
	while (action) {
		printk(KERN_ERR "[<%p>]", action->handler);
		print_symbol(" (%s)",
			(unsigned long)action->handler);
		printk("\n");
		action = action->next;
	}
	raw_spin_unlock_irqrestore(&desc->lock, flags);
}

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->irq_data.chip->irq_disable(&desc->irq_data);

		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
bd151412 TG	17	#include "internals.h"
bd151412 TG	18
83d4e6e7	19	static int irqfixup __read_mostly;
200803df	20
f84dbb91 EB	21	#define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10)
	22	static void poll_spurious_irqs(unsigned long dummy);
	23	static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs, 0, 0);
	24
200803df AC	25	/*
	26	* Recovery handler for misrouted interrupts.
	27	*/
f84dbb91	28	static int try_one_irq(int irq, struct irq_desc *desc)
200803df	29	{
f84dbb91	30	struct irqaction *action;
d3c60047	31	int ok = 0, work = 0;
200803df	32
239007b8	33	raw_spin_lock(&desc->lock);
f84dbb91 EB	34	/* Already running on another processor */
	35	if (desc->status & IRQ_INPROGRESS) {
	36	/*
	37	* Already running: If it is shared get the other
	38	* CPU to go looking for our mystery interrupt too
	39	*/
	40	if (desc->action && (desc->action->flags & IRQF_SHARED))
	41	desc->status \|= IRQ_PENDING;
239007b8	42	raw_spin_unlock(&desc->lock);
f84dbb91 EB	43	return ok;
f84dbb91 EB	44	}
f84dbb91	45	/*
fa27271b TG	46	* All handlers must agree on IRQF_SHARED, so we test just the
fa27271b TG	47	* first. Check for action->next as well.
f84dbb91	48	*/
fa27271b TG	49	action = desc->action;
	50	if (!action \|\| !(action->flags & IRQF_SHARED) \|\| !action->next)
	51	goto out;
	52
	53	/* Honour the normal IRQ locking */
	54	desc->status \|= IRQ_INPROGRESS;
	55	do {
	56	work++;
	57	desc->status &= ~IRQ_PENDING;
239007b8	58	raw_spin_unlock(&desc->lock);
fa27271b TG	59	if (handle_IRQ_event(irq, action) != IRQ_NONE)
fa27271b TG	60	ok = 1;
239007b8	61	raw_spin_lock(&desc->lock);
fa27271b TG	62	action = desc->action;
	63	} while ((desc->status & IRQ_PENDING) && action);
	64
f84dbb91 EB	65	desc->status &= ~IRQ_INPROGRESS;
	66	/*
	67	* If we did actual work for the real IRQ line we must let the
	68	* IRQ controller clean up too
	69	*/
fa27271b	70	if (work > 1)
bd151412	71	irq_end(irq, desc);
f84dbb91	72
fa27271b TG	73	out:
fa27271b TG	74	raw_spin_unlock(&desc->lock);
f84dbb91 EB	75	return ok;
	76	}
	77
	78	static int misrouted_irq(int irq)
	79	{
e00585bb	80	struct irq_desc *desc;
d3c60047	81	int i, ok = 0;
f84dbb91	82
e00585bb YL	83	for_each_irq_desc(i, desc) {
	84	if (!i)
	85	continue;
f84dbb91 EB	86
	87	if (i == irq) /* Already tried */
	88	continue;
	89
	90	if (try_one_irq(i, desc))
	91	ok = 1;
200803df AC	92	}
	93	/* So the caller can adjust the irq error counts */
	94	return ok;
	95	}
	96
663e6959	97	static void poll_spurious_irqs(unsigned long dummy)
f84dbb91	98	{
e00585bb	99	struct irq_desc *desc;
d3c60047	100	int i;
e00585bb YL	101
e00585bb YL	102	for_each_irq_desc(i, desc) {
f84dbb91 EB	103	unsigned int status;
f84dbb91 EB	104
e00585bb YL	105	if (!i)
	106	continue;
	107
f84dbb91 EB	108	/* Racy but it doesn't matter */
	109	status = desc->status;
	110	barrier();
	111	if (!(status & IRQ_SPURIOUS_DISABLED))
	112	continue;
	113
e7e7e0c0	114	local_irq_disable();
f84dbb91	115	try_one_irq(i, desc);
e7e7e0c0	116	local_irq_enable();
f84dbb91 EB	117	}
f84dbb91 EB	118
d3c60047 TG	119	mod_timer(&poll_spurious_irq_timer,
d3c60047 TG	120	jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
f84dbb91 EB	121	}
f84dbb91 EB	122
1da177e4 LT	123	/*
	124	* If 99,900 of the previous 100,000 interrupts have not been handled
	125	* then assume that the IRQ is stuck in some manner. Drop a diagnostic
	126	* and try to turn the IRQ off.
	127	*
	128	* (The other 100-of-100,000 interrupts may have been a correctly
	129	* functioning device sharing an IRQ with the failing one)
1da177e4	130	*/
1da177e4	131	static void
34ffdb72 IM	132	__report_bad_irq(unsigned int irq, struct irq_desc *desc,
34ffdb72 IM	133	irqreturn_t action_ret)
1da177e4 LT	134	{
1da177e4 LT	135	struct irqaction *action;
1082687e	136	unsigned long flags;
1da177e4 LT	137
	138	if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
	139	printk(KERN_ERR "irq event %d: bogus return value %x\n",
	140	irq, action_ret);
	141	} else {
200803df AC	142	printk(KERN_ERR "irq %d: nobody cared (try booting with "
200803df AC	143	"the \"irqpoll\" option)\n", irq);
1da177e4 LT	144	}
	145	dump_stack();
	146	printk(KERN_ERR "handlers:\n");
06fcb0c6	147
1082687e TG	148	/*
	149	* We need to take desc->lock here. note_interrupt() is called
	150	* w/o desc->lock held, but IRQ_PROGRESS set. We might race
	151	* with something else removing an action. It's ok to take
	152	* desc->lock here. See synchronize_irq().
	153	*/
	154	raw_spin_lock_irqsave(&desc->lock, flags);
1da177e4 LT	155	action = desc->action;
	156	while (action) {
	157	printk(KERN_ERR "[<%p>]", action->handler);
	158	print_symbol(" (%s)",
	159	(unsigned long)action->handler);
	160	printk("\n");
	161	action = action->next;
	162	}
1082687e	163	raw_spin_unlock_irqrestore(&desc->lock, flags);
1da177e4 LT	164	}
1da177e4 LT	165
06fcb0c6	166	static void
34ffdb72	167	report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
1da177e4 LT	168	{
	169	static int count = 100;
	170
	171	if (count > 0) {
	172	count--;
	173	__report_bad_irq(irq, desc, action_ret);
	174	}
	175	}
	176
d3c60047 TG	177	static inline int
	178	try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
	179	irqreturn_t action_ret)
92ea7727 LT	180	{
	181	struct irqaction *action;
	182
	183	if (!irqfixup)
	184	return 0;
	185
	186	/* We didn't actually handle the IRQ - see if it was misrouted? */
	187	if (action_ret == IRQ_NONE)
	188	return 1;
	189
	190	/*
	191	* But for 'irqfixup == 2' we also do it for handled interrupts if
	192	* they are marked as IRQF_IRQPOLL (or for irq zero, which is the
	193	* traditional PC timer interrupt.. Legacy)
	194	*/
	195	if (irqfixup < 2)
	196	return 0;
	197
	198	if (!irq)
	199	return 1;
	200
	201	/*
	202	* Since we don't get the descriptor lock, "action" can
	203	* change under us. We don't really care, but we don't
	204	* want to follow a NULL pointer. So tell the compiler to
	205	* just load it once by using a barrier.
	206	*/
	207	action = desc->action;
	208	barrier();
	209	return action && (action->flags & IRQF_IRQPOLL);
	210	}
	211
34ffdb72	212	void note_interrupt(unsigned int irq, struct irq_desc *desc,
7d12e780	213	irqreturn_t action_ret)
1da177e4	214	{
83d4e6e7	215	if (unlikely(action_ret != IRQ_HANDLED)) {
4f27c00b AC	216	/*
	217	* If we are seeing only the odd spurious IRQ caused by
	218	* bus asynchronicity then don't eventually trigger an error,
fbfecd37	219	* otherwise the counter becomes a doomsday timer for otherwise
4f27c00b AC	220	* working systems
4f27c00b AC	221	*/
188fd89d	222	if (time_after(jiffies, desc->last_unhandled + HZ/10))
4f27c00b AC	223	desc->irqs_unhandled = 1;
	224	else
	225	desc->irqs_unhandled++;
	226	desc->last_unhandled = jiffies;
83d4e6e7	227	if (unlikely(action_ret != IRQ_NONE))
1da177e4 LT	228	report_bad_irq(irq, desc, action_ret);
	229	}
	230
92ea7727 LT	231	if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
	232	int ok = misrouted_irq(irq);
	233	if (action_ret == IRQ_NONE)
	234	desc->irqs_unhandled -= ok;
200803df AC	235	}
200803df AC	236
1da177e4	237	desc->irq_count++;
83d4e6e7	238	if (likely(desc->irq_count < 100000))
1da177e4 LT	239	return;
	240
	241	desc->irq_count = 0;
83d4e6e7	242	if (unlikely(desc->irqs_unhandled > 99900)) {
1da177e4 LT	243	/*
	244	* The interrupt is stuck
	245	*/
	246	__report_bad_irq(irq, desc, action_ret);
	247	/*
	248	* Now kill the IRQ
	249	*/
	250	printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
1adb0850 TG	251	desc->status \|= IRQ_DISABLED \| IRQ_SPURIOUS_DISABLED;
1adb0850 TG	252	desc->depth++;
bc310dda	253	desc->irq_data.chip->irq_disable(&desc->irq_data);
f84dbb91	254
d3c60047 TG	255	mod_timer(&poll_spurious_irq_timer,
d3c60047 TG	256	jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
1da177e4 LT	257	}
	258	desc->irqs_unhandled = 0;
	259	}
	260
83d4e6e7	261	int noirqdebug __read_mostly;
1da177e4	262
343cde51	263	int noirqdebug_setup(char *str)
1da177e4 LT	264	{
	265	noirqdebug = 1;
	266	printk(KERN_INFO "IRQ lockup detection disabled\n");
06fcb0c6	267
1da177e4 LT	268	return 1;
	269	}
	270
	271	__setup("noirqdebug", noirqdebug_setup);
9e094c17 AK	272	module_param(noirqdebug, bool, 0644);
9e094c17 AK	273	MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
1da177e4	274
200803df AC	275	static int __init irqfixup_setup(char *str)
	276	{
	277	irqfixup = 1;
	278	printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
	279	printk(KERN_WARNING "This may impact system performance.\n");
06fcb0c6	280
200803df AC	281	return 1;
	282	}
	283
	284	__setup("irqfixup", irqfixup_setup);
9e094c17	285	module_param(irqfixup, int, 0644);
200803df AC	286
	287	static int __init irqpoll_setup(char *str)
	288	{
	289	irqfixup = 2;
	290	printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
	291	"enabled\n");
	292	printk(KERN_WARNING "This may significantly impact system "
	293	"performance\n");
	294	return 1;
	295	}
	296
	297	__setup("irqpoll", irqpoll_setup);