[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>

#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;
	}
	/* 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)
		irq_end(irq, desc);
	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->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;
	44	}
	45	/* Honour the normal IRQ locking */
	46	desc->status \|= IRQ_INPROGRESS;
	47	action = desc->action;
239007b8	48	raw_spin_unlock(&desc->lock);
06fcb0c6	49
f84dbb91 EB	50	while (action) {
	51	/* Only shared IRQ handlers are safe to call */
	52	if (action->flags & IRQF_SHARED) {
	53	if (action->handler(irq, action->dev_id) ==
	54	IRQ_HANDLED)
	55	ok = 1;
200803df	56	}
f84dbb91 EB	57	action = action->next;
	58	}
	59	local_irq_disable();
	60	/* Now clean up the flags */
239007b8	61	raw_spin_lock(&desc->lock);
f84dbb91	62	action = desc->action;
200803df	63
f84dbb91 EB	64	/*
	65	* While we were looking for a fixup someone queued a real
	66	* IRQ clashing with our walk:
	67	*/
	68	while ((desc->status & IRQ_PENDING) && action) {
200803df	69	/*
f84dbb91	70	* Perform real IRQ processing for the IRQ we deferred
200803df	71	*/
f84dbb91	72	work = 1;
239007b8	73	raw_spin_unlock(&desc->lock);
f84dbb91	74	handle_IRQ_event(irq, action);
239007b8	75	raw_spin_lock(&desc->lock);
f84dbb91 EB	76	desc->status &= ~IRQ_PENDING;
	77	}
	78	desc->status &= ~IRQ_INPROGRESS;
	79	/*
	80	* If we did actual work for the real IRQ line we must let the
	81	* IRQ controller clean up too
	82	*/
bd151412 TG	83	if (work)
bd151412 TG	84	irq_end(irq, desc);
239007b8	85	raw_spin_unlock(&desc->lock);
f84dbb91 EB	86
	87	return ok;
	88	}
	89
	90	static int misrouted_irq(int irq)
	91	{
e00585bb	92	struct irq_desc *desc;
d3c60047	93	int i, ok = 0;
f84dbb91	94
e00585bb YL	95	for_each_irq_desc(i, desc) {
	96	if (!i)
	97	continue;
f84dbb91 EB	98
	99	if (i == irq) /* Already tried */
	100	continue;
	101
	102	if (try_one_irq(i, desc))
	103	ok = 1;
200803df AC	104	}
	105	/* So the caller can adjust the irq error counts */
	106	return ok;
	107	}
	108
663e6959	109	static void poll_spurious_irqs(unsigned long dummy)
f84dbb91	110	{
e00585bb	111	struct irq_desc *desc;
d3c60047	112	int i;
e00585bb YL	113
e00585bb YL	114	for_each_irq_desc(i, desc) {
f84dbb91 EB	115	unsigned int status;
f84dbb91 EB	116
e00585bb YL	117	if (!i)
	118	continue;
	119
f84dbb91 EB	120	/* Racy but it doesn't matter */
	121	status = desc->status;
	122	barrier();
	123	if (!(status & IRQ_SPURIOUS_DISABLED))
	124	continue;
	125
e7e7e0c0	126	local_irq_disable();
f84dbb91	127	try_one_irq(i, desc);
e7e7e0c0	128	local_irq_enable();
f84dbb91 EB	129	}
f84dbb91 EB	130
d3c60047 TG	131	mod_timer(&poll_spurious_irq_timer,
d3c60047 TG	132	jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
f84dbb91 EB	133	}
f84dbb91 EB	134
1da177e4 LT	135	/*
	136	* If 99,900 of the previous 100,000 interrupts have not been handled
	137	* then assume that the IRQ is stuck in some manner. Drop a diagnostic
	138	* and try to turn the IRQ off.
	139	*
	140	* (The other 100-of-100,000 interrupts may have been a correctly
	141	* functioning device sharing an IRQ with the failing one)
	142	*
	143	* Called under desc->lock
	144	*/
	145
	146	static void
34ffdb72 IM	147	__report_bad_irq(unsigned int irq, struct irq_desc *desc,
34ffdb72 IM	148	irqreturn_t action_ret)
1da177e4 LT	149	{
	150	struct irqaction *action;
	151
	152	if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
	153	printk(KERN_ERR "irq event %d: bogus return value %x\n",
	154	irq, action_ret);
	155	} else {
200803df AC	156	printk(KERN_ERR "irq %d: nobody cared (try booting with "
200803df AC	157	"the \"irqpoll\" option)\n", irq);
1da177e4 LT	158	}
	159	dump_stack();
	160	printk(KERN_ERR "handlers:\n");
06fcb0c6	161
1da177e4 LT	162	action = desc->action;
	163	while (action) {
	164	printk(KERN_ERR "[<%p>]", action->handler);
	165	print_symbol(" (%s)",
	166	(unsigned long)action->handler);
	167	printk("\n");
	168	action = action->next;
	169	}
	170	}
	171
06fcb0c6	172	static void
34ffdb72	173	report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
1da177e4 LT	174	{
	175	static int count = 100;
	176
	177	if (count > 0) {
	178	count--;
	179	__report_bad_irq(irq, desc, action_ret);
	180	}
	181	}
	182
d3c60047 TG	183	static inline int
	184	try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
	185	irqreturn_t action_ret)
92ea7727 LT	186	{
	187	struct irqaction *action;
	188
	189	if (!irqfixup)
	190	return 0;
	191
	192	/* We didn't actually handle the IRQ - see if it was misrouted? */
	193	if (action_ret == IRQ_NONE)
	194	return 1;
	195
	196	/*
	197	* But for 'irqfixup == 2' we also do it for handled interrupts if
	198	* they are marked as IRQF_IRQPOLL (or for irq zero, which is the
	199	* traditional PC timer interrupt.. Legacy)
	200	*/
	201	if (irqfixup < 2)
	202	return 0;
	203
	204	if (!irq)
	205	return 1;
	206
	207	/*
	208	* Since we don't get the descriptor lock, "action" can
	209	* change under us. We don't really care, but we don't
	210	* want to follow a NULL pointer. So tell the compiler to
	211	* just load it once by using a barrier.
	212	*/
	213	action = desc->action;
	214	barrier();
	215	return action && (action->flags & IRQF_IRQPOLL);
	216	}
	217
34ffdb72	218	void note_interrupt(unsigned int irq, struct irq_desc *desc,
7d12e780	219	irqreturn_t action_ret)
1da177e4	220	{
83d4e6e7	221	if (unlikely(action_ret != IRQ_HANDLED)) {
4f27c00b AC	222	/*
	223	* If we are seeing only the odd spurious IRQ caused by
	224	* bus asynchronicity then don't eventually trigger an error,
fbfecd37	225	* otherwise the counter becomes a doomsday timer for otherwise
4f27c00b AC	226	* working systems
4f27c00b AC	227	*/
188fd89d	228	if (time_after(jiffies, desc->last_unhandled + HZ/10))
4f27c00b AC	229	desc->irqs_unhandled = 1;
	230	else
	231	desc->irqs_unhandled++;
	232	desc->last_unhandled = jiffies;
83d4e6e7	233	if (unlikely(action_ret != IRQ_NONE))
1da177e4 LT	234	report_bad_irq(irq, desc, action_ret);
	235	}
	236
92ea7727 LT	237	if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
	238	int ok = misrouted_irq(irq);
	239	if (action_ret == IRQ_NONE)
	240	desc->irqs_unhandled -= ok;
200803df AC	241	}
200803df AC	242
1da177e4	243	desc->irq_count++;
83d4e6e7	244	if (likely(desc->irq_count < 100000))
1da177e4 LT	245	return;
	246
	247	desc->irq_count = 0;
83d4e6e7	248	if (unlikely(desc->irqs_unhandled > 99900)) {
1da177e4 LT	249	/*
	250	* The interrupt is stuck
	251	*/
	252	__report_bad_irq(irq, desc, action_ret);
	253	/*
	254	* Now kill the IRQ
	255	*/
	256	printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
1adb0850 TG	257	desc->status \|= IRQ_DISABLED \| IRQ_SPURIOUS_DISABLED;
1adb0850 TG	258	desc->depth++;
bc310dda	259	desc->irq_data.chip->irq_disable(&desc->irq_data);
f84dbb91	260
d3c60047 TG	261	mod_timer(&poll_spurious_irq_timer,
d3c60047 TG	262	jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
1da177e4 LT	263	}
	264	desc->irqs_unhandled = 0;
	265	}
	266
83d4e6e7	267	int noirqdebug __read_mostly;
1da177e4	268
343cde51	269	int noirqdebug_setup(char *str)
1da177e4 LT	270	{
	271	noirqdebug = 1;
	272	printk(KERN_INFO "IRQ lockup detection disabled\n");
06fcb0c6	273
1da177e4 LT	274	return 1;
	275	}
	276
	277	__setup("noirqdebug", noirqdebug_setup);
9e094c17 AK	278	module_param(noirqdebug, bool, 0644);
9e094c17 AK	279	MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
1da177e4	280
200803df AC	281	static int __init irqfixup_setup(char *str)
	282	{
	283	irqfixup = 1;
	284	printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
	285	printk(KERN_WARNING "This may impact system performance.\n");
06fcb0c6	286
200803df AC	287	return 1;
	288	}
	289
	290	__setup("irqfixup", irqfixup_setup);
9e094c17	291	module_param(irqfixup, int, 0644);
200803df AC	292
	293	static int __init irqpoll_setup(char *str)
	294	{
	295	irqfixup = 2;
	296	printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
	297	"enabled\n");
	298	printk(KERN_WARNING "This may significantly impact system "
	299	"performance\n");
	300	return 1;
	301	}
	302
	303	__setup("irqpoll", irqpoll_setup);