[GitHub/mt8127/android_kernel_alcatel_ttab.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);
static int irq_poll_cpu;
static atomic_t irq_poll_active;

/*
 * We wait here for a poller to finish.
 *
 * If the poll runs on this CPU, then we yell loudly and return
 * false. That will leave the interrupt line disabled in the worst
 * case, but it should never happen.
 *
 * We wait until the poller is done and then recheck disabled and
 * action (about to be disabled). Only if it's still active, we return
 * true and let the handler run.
 */
bool irq_wait_for_poll(struct irq_desc *desc)
{
	if (WARN_ONCE(irq_poll_cpu == smp_processor_id(),
		      "irq poll in progress on cpu %d for irq %d\n",
		      smp_processor_id(), desc->irq_data.irq))
		return false;

#ifdef CONFIG_SMP
	do {
		raw_spin_unlock(&desc->lock);
		while (desc->status & IRQ_INPROGRESS)
			cpu_relax();
		raw_spin_lock(&desc->lock);
	} while (desc->status & IRQ_INPROGRESS);
	/* Might have been disabled in meantime */
	return !(desc->status & IRQ_DISABLED) && desc->action;
#else
	return false;
#endif
}


/*
 * Recovery handler for misrouted interrupts.
 */
static int try_one_irq(int irq, struct irq_desc *desc, bool force)
{
	irqreturn_t ret = IRQ_NONE;
	struct irqaction *action;

	raw_spin_lock(&desc->lock);

	/* PER_CPU and nested thread interrupts are never polled */
	if (desc->status & (IRQ_PER_CPU | IRQ_NESTED_THREAD))
		goto out;

	/*
	 * Do not poll disabled interrupts unless the spurious
	 * disabled poller asks explicitely.
	 */
	if ((desc->status & IRQ_DISABLED) && !force)
		goto out;

	/*
	 * 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->flags & __IRQF_TIMER) || !action->next)
		goto out;

	/* 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
		 */
		desc->status |= IRQ_PENDING;
		goto out;
	}

	/* Mark it poll in progress */
	desc->status |= IRQ_POLL_INPROGRESS;
	do {
		if (handle_irq_event(desc) == IRQ_HANDLED)
			ret = IRQ_HANDLED;
		action = desc->action;
	} while ((desc->status & IRQ_PENDING) && action);
	desc->status &= ~IRQ_POLL_INPROGRESS;
out:
	raw_spin_unlock(&desc->lock);
	return ret == IRQ_HANDLED;
}

static int misrouted_irq(int irq)
{
	struct irq_desc *desc;
	int i, ok = 0;

	if (atomic_inc_return(&irq_poll_active) == 1)
		goto out;

	irq_poll_cpu = smp_processor_id();

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

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

		if (try_one_irq(i, desc, false))
			ok = 1;
	}
out:
	atomic_dec(&irq_poll_active);
	/* 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;

	if (atomic_inc_return(&irq_poll_active) != 1)
		goto out;
	irq_poll_cpu = smp_processor_id();

	for_each_irq_desc(i, desc) {
		unsigned int state;

		if (!i)
			 continue;

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

		local_irq_disable();
		try_one_irq(i, desc, true);
		local_irq_enable();
	}
out:
	atomic_dec(&irq_poll_active);
	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 (desc->status & IRQ_POLL_INPROGRESS)
		return;

	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->istate |= IRQS_SPURIOUS_DISABLED;
		desc->depth++;
		irq_disable(desc);

		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);
d05c65ff TG	24	static int irq_poll_cpu;
d05c65ff TG	25	static atomic_t irq_poll_active;
f84dbb91	26
fe200ae4 TG	27	/*
	28	* We wait here for a poller to finish.
	29	*
	30	* If the poll runs on this CPU, then we yell loudly and return
	31	* false. That will leave the interrupt line disabled in the worst
	32	* case, but it should never happen.
	33	*
	34	* We wait until the poller is done and then recheck disabled and
	35	* action (about to be disabled). Only if it's still active, we return
	36	* true and let the handler run.
	37	*/
	38	bool irq_wait_for_poll(struct irq_desc *desc)
	39	{
	40	if (WARN_ONCE(irq_poll_cpu == smp_processor_id(),
	41	"irq poll in progress on cpu %d for irq %d\n",
	42	smp_processor_id(), desc->irq_data.irq))
	43	return false;
	44
	45	#ifdef CONFIG_SMP
	46	do {
	47	raw_spin_unlock(&desc->lock);
	48	while (desc->status & IRQ_INPROGRESS)
	49	cpu_relax();
	50	raw_spin_lock(&desc->lock);
	51	} while (desc->status & IRQ_INPROGRESS);
	52	/* Might have been disabled in meantime */
	53	return !(desc->status & IRQ_DISABLED) && desc->action;
	54	#else
	55	return false;
	56	#endif
	57	}
	58
0877d662	59
200803df AC	60	/*
	61	* Recovery handler for misrouted interrupts.
	62	*/
c7259cd7	63	static int try_one_irq(int irq, struct irq_desc *desc, bool force)
200803df	64	{
0877d662	65	irqreturn_t ret = IRQ_NONE;
f84dbb91	66	struct irqaction *action;
200803df	67
239007b8	68	raw_spin_lock(&desc->lock);
c7259cd7 TG	69
	70	/* PER_CPU and nested thread interrupts are never polled */
	71	if (desc->status & (IRQ_PER_CPU \| IRQ_NESTED_THREAD))
	72	goto out;
	73
	74	/*
	75	* Do not poll disabled interrupts unless the spurious
	76	* disabled poller asks explicitely.
	77	*/
	78	if ((desc->status & IRQ_DISABLED) && !force)
	79	goto out;
	80
	81	/*
	82	* All handlers must agree on IRQF_SHARED, so we test just the
	83	* first. Check for action->next as well.
	84	*/
	85	action = desc->action;
	86	if (!action \|\| !(action->flags & IRQF_SHARED) \|\|
	87	(action->flags & __IRQF_TIMER) \|\| !action->next)
	88	goto out;
	89
f84dbb91 EB	90	/* Already running on another processor */
	91	if (desc->status & IRQ_INPROGRESS) {
	92	/*
	93	* Already running: If it is shared get the other
	94	* CPU to go looking for our mystery interrupt too
	95	*/
c7259cd7	96	desc->status \|= IRQ_PENDING;
fa27271b	97	goto out;
c7259cd7	98	}
fa27271b	99
0877d662 TG	100	/* Mark it poll in progress */
0877d662 TG	101	desc->status \|= IRQ_POLL_INPROGRESS;
fa27271b	102	do {
0877d662 TG	103	if (handle_irq_event(desc) == IRQ_HANDLED)
0877d662 TG	104	ret = IRQ_HANDLED;
fa27271b	105	action = desc->action;
0877d662 TG	106	} while ((desc->status & IRQ_PENDING) && action);
0877d662 TG	107	desc->status &= ~IRQ_POLL_INPROGRESS;
fa27271b TG	108	out:
fa27271b TG	109	raw_spin_unlock(&desc->lock);
0877d662	110	return ret == IRQ_HANDLED;
f84dbb91 EB	111	}
	112
	113	static int misrouted_irq(int irq)
	114	{
e00585bb	115	struct irq_desc *desc;
d3c60047	116	int i, ok = 0;
f84dbb91	117
d05c65ff TG	118	if (atomic_inc_return(&irq_poll_active) == 1)
	119	goto out;
	120
	121	irq_poll_cpu = smp_processor_id();
	122
e00585bb YL	123	for_each_irq_desc(i, desc) {
	124	if (!i)
	125	continue;
f84dbb91 EB	126
	127	if (i == irq) /* Already tried */
	128	continue;
	129
c7259cd7	130	if (try_one_irq(i, desc, false))
f84dbb91	131	ok = 1;
200803df	132	}
d05c65ff TG	133	out:
d05c65ff TG	134	atomic_dec(&irq_poll_active);
200803df AC	135	/* So the caller can adjust the irq error counts */
	136	return ok;
	137	}
	138
663e6959	139	static void poll_spurious_irqs(unsigned long dummy)
f84dbb91	140	{
e00585bb	141	struct irq_desc *desc;
d3c60047	142	int i;
e00585bb	143
d05c65ff TG	144	if (atomic_inc_return(&irq_poll_active) != 1)
	145	goto out;
	146	irq_poll_cpu = smp_processor_id();
	147
e00585bb	148	for_each_irq_desc(i, desc) {
7acdd53e	149	unsigned int state;
f84dbb91	150
e00585bb YL	151	if (!i)
	152	continue;
	153
f84dbb91	154	/* Racy but it doesn't matter */
7acdd53e	155	state = desc->istate;
f84dbb91	156	barrier();
7acdd53e	157	if (!(state & IRQS_SPURIOUS_DISABLED))
f84dbb91 EB	158	continue;
f84dbb91 EB	159
e7e7e0c0	160	local_irq_disable();
c7259cd7	161	try_one_irq(i, desc, true);
e7e7e0c0	162	local_irq_enable();
f84dbb91	163	}
d05c65ff TG	164	out:
d05c65ff TG	165	atomic_dec(&irq_poll_active);
d3c60047 TG	166	mod_timer(&poll_spurious_irq_timer,
d3c60047 TG	167	jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
f84dbb91 EB	168	}
f84dbb91 EB	169
1da177e4 LT	170	/*
	171	* If 99,900 of the previous 100,000 interrupts have not been handled
	172	* then assume that the IRQ is stuck in some manner. Drop a diagnostic
	173	* and try to turn the IRQ off.
	174	*
	175	* (The other 100-of-100,000 interrupts may have been a correctly
	176	* functioning device sharing an IRQ with the failing one)
1da177e4	177	*/
1da177e4	178	static void
34ffdb72 IM	179	__report_bad_irq(unsigned int irq, struct irq_desc *desc,
34ffdb72 IM	180	irqreturn_t action_ret)
1da177e4 LT	181	{
1da177e4 LT	182	struct irqaction *action;
1082687e	183	unsigned long flags;
1da177e4 LT	184
	185	if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
	186	printk(KERN_ERR "irq event %d: bogus return value %x\n",
	187	irq, action_ret);
	188	} else {
200803df AC	189	printk(KERN_ERR "irq %d: nobody cared (try booting with "
200803df AC	190	"the \"irqpoll\" option)\n", irq);
1da177e4 LT	191	}
	192	dump_stack();
	193	printk(KERN_ERR "handlers:\n");
06fcb0c6	194
1082687e TG	195	/*
	196	* We need to take desc->lock here. note_interrupt() is called
	197	* w/o desc->lock held, but IRQ_PROGRESS set. We might race
	198	* with something else removing an action. It's ok to take
	199	* desc->lock here. See synchronize_irq().
	200	*/
	201	raw_spin_lock_irqsave(&desc->lock, flags);
1da177e4 LT	202	action = desc->action;
	203	while (action) {
	204	printk(KERN_ERR "[<%p>]", action->handler);
	205	print_symbol(" (%s)",
	206	(unsigned long)action->handler);
	207	printk("\n");
	208	action = action->next;
	209	}
1082687e	210	raw_spin_unlock_irqrestore(&desc->lock, flags);
1da177e4 LT	211	}
1da177e4 LT	212
06fcb0c6	213	static void
34ffdb72	214	report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
1da177e4 LT	215	{
	216	static int count = 100;
	217
	218	if (count > 0) {
	219	count--;
	220	__report_bad_irq(irq, desc, action_ret);
	221	}
	222	}
	223
d3c60047 TG	224	static inline int
	225	try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
	226	irqreturn_t action_ret)
92ea7727 LT	227	{
	228	struct irqaction *action;
	229
	230	if (!irqfixup)
	231	return 0;
	232
	233	/* We didn't actually handle the IRQ - see if it was misrouted? */
	234	if (action_ret == IRQ_NONE)
	235	return 1;
	236
	237	/*
	238	* But for 'irqfixup == 2' we also do it for handled interrupts if
	239	* they are marked as IRQF_IRQPOLL (or for irq zero, which is the
	240	* traditional PC timer interrupt.. Legacy)
	241	*/
	242	if (irqfixup < 2)
	243	return 0;
	244
	245	if (!irq)
	246	return 1;
	247
	248	/*
	249	* Since we don't get the descriptor lock, "action" can
	250	* change under us. We don't really care, but we don't
	251	* want to follow a NULL pointer. So tell the compiler to
	252	* just load it once by using a barrier.
	253	*/
	254	action = desc->action;
	255	barrier();
	256	return action && (action->flags & IRQF_IRQPOLL);
	257	}
	258
34ffdb72	259	void note_interrupt(unsigned int irq, struct irq_desc *desc,
7d12e780	260	irqreturn_t action_ret)
1da177e4	261	{
fe200ae4 TG	262	if (desc->status & IRQ_POLL_INPROGRESS)
	263	return;
	264
83d4e6e7	265	if (unlikely(action_ret != IRQ_HANDLED)) {
4f27c00b AC	266	/*
	267	* If we are seeing only the odd spurious IRQ caused by
	268	* bus asynchronicity then don't eventually trigger an error,
fbfecd37	269	* otherwise the counter becomes a doomsday timer for otherwise
4f27c00b AC	270	* working systems
4f27c00b AC	271	*/
188fd89d	272	if (time_after(jiffies, desc->last_unhandled + HZ/10))
4f27c00b AC	273	desc->irqs_unhandled = 1;
	274	else
	275	desc->irqs_unhandled++;
	276	desc->last_unhandled = jiffies;
83d4e6e7	277	if (unlikely(action_ret != IRQ_NONE))
1da177e4 LT	278	report_bad_irq(irq, desc, action_ret);
	279	}
	280
92ea7727 LT	281	if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
	282	int ok = misrouted_irq(irq);
	283	if (action_ret == IRQ_NONE)
	284	desc->irqs_unhandled -= ok;
200803df AC	285	}
200803df AC	286
1da177e4	287	desc->irq_count++;
83d4e6e7	288	if (likely(desc->irq_count < 100000))
1da177e4 LT	289	return;
	290
	291	desc->irq_count = 0;
83d4e6e7	292	if (unlikely(desc->irqs_unhandled > 99900)) {
1da177e4 LT	293	/*
	294	* The interrupt is stuck
	295	*/
	296	__report_bad_irq(irq, desc, action_ret);
	297	/*
	298	* Now kill the IRQ
	299	*/
	300	printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
7acdd53e	301	desc->istate \|= IRQS_SPURIOUS_DISABLED;
1adb0850	302	desc->depth++;
87923470	303	irq_disable(desc);
f84dbb91	304
d3c60047 TG	305	mod_timer(&poll_spurious_irq_timer,
d3c60047 TG	306	jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
1da177e4 LT	307	}
	308	desc->irqs_unhandled = 0;
	309	}
	310
83d4e6e7	311	int noirqdebug __read_mostly;
1da177e4	312
343cde51	313	int noirqdebug_setup(char *str)
1da177e4 LT	314	{
	315	noirqdebug = 1;
	316	printk(KERN_INFO "IRQ lockup detection disabled\n");
06fcb0c6	317
1da177e4 LT	318	return 1;
	319	}
	320
	321	__setup("noirqdebug", noirqdebug_setup);
9e094c17 AK	322	module_param(noirqdebug, bool, 0644);
9e094c17 AK	323	MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
1da177e4	324
200803df AC	325	static int __init irqfixup_setup(char *str)
	326	{
	327	irqfixup = 1;
	328	printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
	329	printk(KERN_WARNING "This may impact system performance.\n");
06fcb0c6	330
200803df AC	331	return 1;
	332	}
	333
	334	__setup("irqfixup", irqfixup_setup);
9e094c17	335	module_param(irqfixup, int, 0644);
200803df AC	336
	337	static int __init irqpoll_setup(char *str)
	338	{
	339	irqfixup = 2;
	340	printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
	341	"enabled\n");
	342	printk(KERN_WARNING "This may significantly impact system "
	343	"performance\n");
	344	return 1;
	345	}
	346
	347	__setup("irqpoll", irqpoll_setup);