1/*
   2 * linux/kernel/irq/manage.c
   3 *
   4 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
   5 * Copyright (C) 2005-2006 Thomas Gleixner
   6 *
   7 * This file contains driver APIs to the irq subsystem.
   8 */
   9
  10#define pr_fmt(fmt) "genirq: " fmt
  11
  12#include <linux/irq.h>
  13#include <linux/kthread.h>
  14#include <linux/module.h>
  15#include <linux/random.h>
  16#include <linux/interrupt.h>
  17#include <linux/slab.h>
  18#include <linux/sched.h>
  19#include <linux/sched/rt.h>
  20#include <linux/task_work.h>
  21
  22#include "internals.h"
  23
  24#ifdef CONFIG_IRQ_FORCED_THREADING
  25__read_mostly bool force_irqthreads;
  26
  27static int __init setup_forced_irqthreads(char *arg)
  28{
  29	force_irqthreads = true;
  30	return 0;
  31}
  32early_param("threadirqs", setup_forced_irqthreads);
  33#endif
  34
  35static void __synchronize_hardirq(struct irq_desc *desc)
 
 
 
 
 
 
 
 
 
 
  36{
 
  37	bool inprogress;
  38
 
 
 
  39	do {
  40		unsigned long flags;
  41
  42		/*
  43		 * Wait until we're out of the critical section.  This might
  44		 * give the wrong answer due to the lack of memory barriers.
  45		 */
  46		while (irqd_irq_inprogress(&desc->irq_data))
  47			cpu_relax();
  48
  49		/* Ok, that indicated we're done: double-check carefully. */
  50		raw_spin_lock_irqsave(&desc->lock, flags);
  51		inprogress = irqd_irq_inprogress(&desc->irq_data);
  52		raw_spin_unlock_irqrestore(&desc->lock, flags);
  53
  54		/* Oops, that failed? */
  55	} while (inprogress);
  56}
  57
  58/**
  59 *	synchronize_hardirq - wait for pending hard IRQ handlers (on other CPUs)
  60 *	@irq: interrupt number to wait for
  61 *
  62 *	This function waits for any pending hard IRQ handlers for this
  63 *	interrupt to complete before returning. If you use this
  64 *	function while holding a resource the IRQ handler may need you
  65 *	will deadlock. It does not take associated threaded handlers
  66 *	into account.
  67 *
  68 *	Do not use this for shutdown scenarios where you must be sure
  69 *	that all parts (hardirq and threaded handler) have completed.
  70 *
  71 *	Returns: false if a threaded handler is active.
  72 *
  73 *	This function may be called - with care - from IRQ context.
  74 */
  75bool synchronize_hardirq(unsigned int irq)
  76{
  77	struct irq_desc *desc = irq_to_desc(irq);
  78
  79	if (desc) {
  80		__synchronize_hardirq(desc);
  81		return !atomic_read(&desc->threads_active);
  82	}
  83
  84	return true;
  85}
  86EXPORT_SYMBOL(synchronize_hardirq);
  87
  88/**
  89 *	synchronize_irq - wait for pending IRQ handlers (on other CPUs)
  90 *	@irq: interrupt number to wait for
  91 *
  92 *	This function waits for any pending IRQ handlers for this interrupt
  93 *	to complete before returning. If you use this function while
  94 *	holding a resource the IRQ handler may need you will deadlock.
  95 *
  96 *	This function may be called - with care - from IRQ context.
  97 */
  98void synchronize_irq(unsigned int irq)
  99{
 100	struct irq_desc *desc = irq_to_desc(irq);
 101
 102	if (desc) {
 103		__synchronize_hardirq(desc);
 104		/*
 105		 * We made sure that no hardirq handler is
 106		 * running. Now verify that no threaded handlers are
 107		 * active.
 108		 */
 109		wait_event(desc->wait_for_threads,
 110			   !atomic_read(&desc->threads_active));
 111	}
 112}
 113EXPORT_SYMBOL(synchronize_irq);
 114
 115#ifdef CONFIG_SMP
 116cpumask_var_t irq_default_affinity;
 117
 118static bool __irq_can_set_affinity(struct irq_desc *desc)
 119{
 120	if (!desc || !irqd_can_balance(&desc->irq_data) ||
 121	    !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
 122		return false;
 123	return true;
 124}
 125
 126/**
 127 *	irq_can_set_affinity - Check if the affinity of a given irq can be set
 128 *	@irq:		Interrupt to check
 129 *
 130 */
 131int irq_can_set_affinity(unsigned int irq)
 132{
 133	return __irq_can_set_affinity(irq_to_desc(irq));
 134}
 135
 136/**
 137 * irq_can_set_affinity_usr - Check if affinity of a irq can be set from user space
 138 * @irq:	Interrupt to check
 139 *
 140 * Like irq_can_set_affinity() above, but additionally checks for the
 141 * AFFINITY_MANAGED flag.
 142 */
 143bool irq_can_set_affinity_usr(unsigned int irq)
 144{
 145	struct irq_desc *desc = irq_to_desc(irq);
 146
 147	return __irq_can_set_affinity(desc) &&
 148		!irqd_affinity_is_managed(&desc->irq_data);
 
 
 
 149}
 150
 151/**
 152 *	irq_set_thread_affinity - Notify irq threads to adjust affinity
 153 *	@desc:		irq descriptor which has affitnity changed
 154 *
 155 *	We just set IRQTF_AFFINITY and delegate the affinity setting
 156 *	to the interrupt thread itself. We can not call
 157 *	set_cpus_allowed_ptr() here as we hold desc->lock and this
 158 *	code can be called from hard interrupt context.
 159 */
 160void irq_set_thread_affinity(struct irq_desc *desc)
 161{
 162	struct irqaction *action;
 163
 164	for_each_action_of_desc(desc, action)
 165		if (action->thread)
 166			set_bit(IRQTF_AFFINITY, &action->thread_flags);
 
 
 167}
 168
 169#ifdef CONFIG_GENERIC_PENDING_IRQ
 170static inline bool irq_can_move_pcntxt(struct irq_data *data)
 171{
 172	return irqd_can_move_in_process_context(data);
 173}
 174static inline bool irq_move_pending(struct irq_data *data)
 175{
 176	return irqd_is_setaffinity_pending(data);
 177}
 178static inline void
 179irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask)
 180{
 181	cpumask_copy(desc->pending_mask, mask);
 182}
 183static inline void
 184irq_get_pending(struct cpumask *mask, struct irq_desc *desc)
 185{
 186	cpumask_copy(mask, desc->pending_mask);
 187}
 188#else
 189static inline bool irq_can_move_pcntxt(struct irq_data *data) { return true; }
 190static inline bool irq_move_pending(struct irq_data *data) { return false; }
 191static inline void
 192irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask) { }
 193static inline void
 194irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { }
 195#endif
 196
 197int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
 198			bool force)
 199{
 200	struct irq_desc *desc = irq_data_to_desc(data);
 201	struct irq_chip *chip = irq_data_get_irq_chip(data);
 202	int ret;
 203
 204	ret = chip->irq_set_affinity(data, mask, force);
 205	switch (ret) {
 206	case IRQ_SET_MASK_OK:
 207	case IRQ_SET_MASK_OK_DONE:
 208		cpumask_copy(desc->irq_common_data.affinity, mask);
 209	case IRQ_SET_MASK_OK_NOCOPY:
 210		irq_set_thread_affinity(desc);
 211		ret = 0;
 212	}
 213
 214	return ret;
 215}
 216
 217int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask,
 218			    bool force)
 219{
 220	struct irq_chip *chip = irq_data_get_irq_chip(data);
 221	struct irq_desc *desc = irq_data_to_desc(data);
 222	int ret = 0;
 223
 224	if (!chip || !chip->irq_set_affinity)
 225		return -EINVAL;
 226
 227	if (irq_can_move_pcntxt(data)) {
 228		ret = irq_do_set_affinity(data, mask, force);
 229	} else {
 230		irqd_set_move_pending(data);
 231		irq_copy_pending(desc, mask);
 232	}
 233
 234	if (desc->affinity_notify) {
 235		kref_get(&desc->affinity_notify->kref);
 236		schedule_work(&desc->affinity_notify->work);
 237	}
 238	irqd_set(data, IRQD_AFFINITY_SET);
 239
 240	return ret;
 241}
 242
 243int __irq_set_affinity(unsigned int irq, const struct cpumask *mask, bool force)
 
 
 
 
 
 
 244{
 245	struct irq_desc *desc = irq_to_desc(irq);
 246	unsigned long flags;
 247	int ret;
 248
 249	if (!desc)
 250		return -EINVAL;
 251
 252	raw_spin_lock_irqsave(&desc->lock, flags);
 253	ret = irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask, force);
 254	raw_spin_unlock_irqrestore(&desc->lock, flags);
 255	return ret;
 256}
 257
 258int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
 259{
 260	unsigned long flags;
 261	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 262
 263	if (!desc)
 264		return -EINVAL;
 265	desc->affinity_hint = m;
 266	irq_put_desc_unlock(desc, flags);
 267	/* set the initial affinity to prevent every interrupt being on CPU0 */
 268	if (m)
 269		__irq_set_affinity(irq, m, false);
 270	return 0;
 271}
 272EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
 273
 274static void irq_affinity_notify(struct work_struct *work)
 275{
 276	struct irq_affinity_notify *notify =
 277		container_of(work, struct irq_affinity_notify, work);
 278	struct irq_desc *desc = irq_to_desc(notify->irq);
 279	cpumask_var_t cpumask;
 280	unsigned long flags;
 281
 282	if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
 283		goto out;
 284
 285	raw_spin_lock_irqsave(&desc->lock, flags);
 286	if (irq_move_pending(&desc->irq_data))
 287		irq_get_pending(cpumask, desc);
 288	else
 289		cpumask_copy(cpumask, desc->irq_common_data.affinity);
 290	raw_spin_unlock_irqrestore(&desc->lock, flags);
 291
 292	notify->notify(notify, cpumask);
 293
 294	free_cpumask_var(cpumask);
 295out:
 296	kref_put(&notify->kref, notify->release);
 297}
 298
 299/**
 300 *	irq_set_affinity_notifier - control notification of IRQ affinity changes
 301 *	@irq:		Interrupt for which to enable/disable notification
 302 *	@notify:	Context for notification, or %NULL to disable
 303 *			notification.  Function pointers must be initialised;
 304 *			the other fields will be initialised by this function.
 305 *
 306 *	Must be called in process context.  Notification may only be enabled
 307 *	after the IRQ is allocated and must be disabled before the IRQ is
 308 *	freed using free_irq().
 309 */
 310int
 311irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
 312{
 313	struct irq_desc *desc = irq_to_desc(irq);
 314	struct irq_affinity_notify *old_notify;
 315	unsigned long flags;
 316
 317	/* The release function is promised process context */
 318	might_sleep();
 319
 320	if (!desc)
 321		return -EINVAL;
 322
 323	/* Complete initialisation of *notify */
 324	if (notify) {
 325		notify->irq = irq;
 326		kref_init(&notify->kref);
 327		INIT_WORK(&notify->work, irq_affinity_notify);
 328	}
 329
 330	raw_spin_lock_irqsave(&desc->lock, flags);
 331	old_notify = desc->affinity_notify;
 332	desc->affinity_notify = notify;
 333	raw_spin_unlock_irqrestore(&desc->lock, flags);
 334
 335	if (old_notify)
 336		kref_put(&old_notify->kref, old_notify->release);
 337
 338	return 0;
 339}
 340EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
 341
 342#ifndef CONFIG_AUTO_IRQ_AFFINITY
 343/*
 344 * Generic version of the affinity autoselector.
 345 */
 346static int setup_affinity(struct irq_desc *desc, struct cpumask *mask)
 
 347{
 348	struct cpumask *set = irq_default_affinity;
 349	int node = irq_desc_get_node(desc);
 350
 351	/* Excludes PER_CPU and NO_BALANCE interrupts */
 352	if (!__irq_can_set_affinity(desc))
 353		return 0;
 354
 355	/*
 356	 * Preserve the managed affinity setting and an userspace affinity
 357	 * setup, but make sure that one of the targets is online.
 358	 */
 359	if (irqd_affinity_is_managed(&desc->irq_data) ||
 360	    irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
 361		if (cpumask_intersects(desc->irq_common_data.affinity,
 362				       cpu_online_mask))
 363			set = desc->irq_common_data.affinity;
 364		else
 365			irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
 366	}
 367
 368	cpumask_and(mask, cpu_online_mask, set);
 369	if (node != NUMA_NO_NODE) {
 370		const struct cpumask *nodemask = cpumask_of_node(node);
 371
 372		/* make sure at least one of the cpus in nodemask is online */
 373		if (cpumask_intersects(mask, nodemask))
 374			cpumask_and(mask, mask, nodemask);
 375	}
 376	irq_do_set_affinity(&desc->irq_data, mask, false);
 377	return 0;
 378}
 379#else
 380/* Wrapper for ALPHA specific affinity selector magic */
 381static inline int setup_affinity(struct irq_desc *d, struct cpumask *mask)
 382{
 383	return irq_select_affinity(irq_desc_get_irq(d));
 384}
 385#endif
 386
 387/*
 388 * Called when affinity is set via /proc/irq
 389 */
 390int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask)
 391{
 392	struct irq_desc *desc = irq_to_desc(irq);
 393	unsigned long flags;
 394	int ret;
 395
 396	raw_spin_lock_irqsave(&desc->lock, flags);
 397	ret = setup_affinity(desc, mask);
 398	raw_spin_unlock_irqrestore(&desc->lock, flags);
 399	return ret;
 400}
 401
 402#else
 403static inline int
 404setup_affinity(struct irq_desc *desc, struct cpumask *mask)
 405{
 406	return 0;
 407}
 408#endif
 409
 410/**
 411 *	irq_set_vcpu_affinity - Set vcpu affinity for the interrupt
 412 *	@irq: interrupt number to set affinity
 413 *	@vcpu_info: vCPU specific data
 414 *
 415 *	This function uses the vCPU specific data to set the vCPU
 416 *	affinity for an irq. The vCPU specific data is passed from
 417 *	outside, such as KVM. One example code path is as below:
 418 *	KVM -> IOMMU -> irq_set_vcpu_affinity().
 419 */
 420int irq_set_vcpu_affinity(unsigned int irq, void *vcpu_info)
 421{
 422	unsigned long flags;
 423	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
 424	struct irq_data *data;
 425	struct irq_chip *chip;
 426	int ret = -ENOSYS;
 427
 428	if (!desc)
 429		return -EINVAL;
 430
 431	data = irq_desc_get_irq_data(desc);
 432	chip = irq_data_get_irq_chip(data);
 433	if (chip && chip->irq_set_vcpu_affinity)
 434		ret = chip->irq_set_vcpu_affinity(data, vcpu_info);
 435	irq_put_desc_unlock(desc, flags);
 436
 437	return ret;
 438}
 439EXPORT_SYMBOL_GPL(irq_set_vcpu_affinity);
 440
 441void __disable_irq(struct irq_desc *desc)
 442{
 443	if (!desc->depth++)
 444		irq_disable(desc);
 445}
 446
 447static int __disable_irq_nosync(unsigned int irq)
 448{
 449	unsigned long flags;
 450	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 451
 452	if (!desc)
 453		return -EINVAL;
 454	__disable_irq(desc);
 455	irq_put_desc_busunlock(desc, flags);
 456	return 0;
 457}
 458
 459/**
 460 *	disable_irq_nosync - disable an irq without waiting
 461 *	@irq: Interrupt to disable
 462 *
 463 *	Disable the selected interrupt line.  Disables and Enables are
 464 *	nested.
 465 *	Unlike disable_irq(), this function does not ensure existing
 466 *	instances of the IRQ handler have completed before returning.
 467 *
 468 *	This function may be called from IRQ context.
 469 */
 470void disable_irq_nosync(unsigned int irq)
 471{
 472	__disable_irq_nosync(irq);
 473}
 474EXPORT_SYMBOL(disable_irq_nosync);
 475
 476/**
 477 *	disable_irq - disable an irq and wait for completion
 478 *	@irq: Interrupt to disable
 479 *
 480 *	Disable the selected interrupt line.  Enables and Disables are
 481 *	nested.
 482 *	This function waits for any pending IRQ handlers for this interrupt
 483 *	to complete before returning. If you use this function while
 484 *	holding a resource the IRQ handler may need you will deadlock.
 485 *
 486 *	This function may be called - with care - from IRQ context.
 487 */
 488void disable_irq(unsigned int irq)
 489{
 490	if (!__disable_irq_nosync(irq))
 491		synchronize_irq(irq);
 492}
 493EXPORT_SYMBOL(disable_irq);
 494
 495/**
 496 *	disable_hardirq - disables an irq and waits for hardirq completion
 497 *	@irq: Interrupt to disable
 498 *
 499 *	Disable the selected interrupt line.  Enables and Disables are
 500 *	nested.
 501 *	This function waits for any pending hard IRQ handlers for this
 502 *	interrupt to complete before returning. If you use this function while
 503 *	holding a resource the hard IRQ handler may need you will deadlock.
 504 *
 505 *	When used to optimistically disable an interrupt from atomic context
 506 *	the return value must be checked.
 507 *
 508 *	Returns: false if a threaded handler is active.
 509 *
 510 *	This function may be called - with care - from IRQ context.
 511 */
 512bool disable_hardirq(unsigned int irq)
 513{
 514	if (!__disable_irq_nosync(irq))
 515		return synchronize_hardirq(irq);
 516
 517	return false;
 518}
 519EXPORT_SYMBOL_GPL(disable_hardirq);
 
 
 
 
 
 520
 521void __enable_irq(struct irq_desc *desc)
 522{
 523	switch (desc->depth) {
 524	case 0:
 525 err_out:
 526		WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n",
 527		     irq_desc_get_irq(desc));
 528		break;
 529	case 1: {
 530		if (desc->istate & IRQS_SUSPENDED)
 531			goto err_out;
 532		/* Prevent probing on this irq: */
 533		irq_settings_set_noprobe(desc);
 534		irq_enable(desc);
 535		check_irq_resend(desc);
 536		/* fall-through */
 537	}
 538	default:
 539		desc->depth--;
 540	}
 541}
 542
 543/**
 544 *	enable_irq - enable handling of an irq
 545 *	@irq: Interrupt to enable
 546 *
 547 *	Undoes the effect of one call to disable_irq().  If this
 548 *	matches the last disable, processing of interrupts on this
 549 *	IRQ line is re-enabled.
 550 *
 551 *	This function may be called from IRQ context only when
 552 *	desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
 553 */
 554void enable_irq(unsigned int irq)
 555{
 556	unsigned long flags;
 557	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 558
 559	if (!desc)
 560		return;
 561	if (WARN(!desc->irq_data.chip,
 562		 KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
 563		goto out;
 564
 565	__enable_irq(desc);
 566out:
 567	irq_put_desc_busunlock(desc, flags);
 568}
 569EXPORT_SYMBOL(enable_irq);
 570
 571static int set_irq_wake_real(unsigned int irq, unsigned int on)
 572{
 573	struct irq_desc *desc = irq_to_desc(irq);
 574	int ret = -ENXIO;
 575
 576	if (irq_desc_get_chip(desc)->flags &  IRQCHIP_SKIP_SET_WAKE)
 577		return 0;
 578
 579	if (desc->irq_data.chip->irq_set_wake)
 580		ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
 581
 582	return ret;
 583}
 584
 585/**
 586 *	irq_set_irq_wake - control irq power management wakeup
 587 *	@irq:	interrupt to control
 588 *	@on:	enable/disable power management wakeup
 589 *
 590 *	Enable/disable power management wakeup mode, which is
 591 *	disabled by default.  Enables and disables must match,
 592 *	just as they match for non-wakeup mode support.
 593 *
 594 *	Wakeup mode lets this IRQ wake the system from sleep
 595 *	states like "suspend to RAM".
 596 */
 597int irq_set_irq_wake(unsigned int irq, unsigned int on)
 598{
 599	unsigned long flags;
 600	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 601	int ret = 0;
 602
 603	if (!desc)
 604		return -EINVAL;
 605
 606	/* wakeup-capable irqs can be shared between drivers that
 607	 * don't need to have the same sleep mode behaviors.
 608	 */
 609	if (on) {
 610		if (desc->wake_depth++ == 0) {
 611			ret = set_irq_wake_real(irq, on);
 612			if (ret)
 613				desc->wake_depth = 0;
 614			else
 615				irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
 616		}
 617	} else {
 618		if (desc->wake_depth == 0) {
 619			WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
 620		} else if (--desc->wake_depth == 0) {
 621			ret = set_irq_wake_real(irq, on);
 622			if (ret)
 623				desc->wake_depth = 1;
 624			else
 625				irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
 626		}
 627	}
 628	irq_put_desc_busunlock(desc, flags);
 629	return ret;
 630}
 631EXPORT_SYMBOL(irq_set_irq_wake);
 632
 633/*
 634 * Internal function that tells the architecture code whether a
 635 * particular irq has been exclusively allocated or is available
 636 * for driver use.
 637 */
 638int can_request_irq(unsigned int irq, unsigned long irqflags)
 639{
 640	unsigned long flags;
 641	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
 642	int canrequest = 0;
 643
 644	if (!desc)
 645		return 0;
 646
 647	if (irq_settings_can_request(desc)) {
 648		if (!desc->action ||
 649		    irqflags & desc->action->flags & IRQF_SHARED)
 650			canrequest = 1;
 651	}
 652	irq_put_desc_unlock(desc, flags);
 653	return canrequest;
 654}
 655
 656int __irq_set_trigger(struct irq_desc *desc, unsigned long flags)
 
 657{
 658	struct irq_chip *chip = desc->irq_data.chip;
 659	int ret, unmask = 0;
 660
 661	if (!chip || !chip->irq_set_type) {
 662		/*
 663		 * IRQF_TRIGGER_* but the PIC does not support multiple
 664		 * flow-types?
 665		 */
 666		pr_debug("No set_type function for IRQ %d (%s)\n",
 667			 irq_desc_get_irq(desc),
 668			 chip ? (chip->name ? : "unknown") : "unknown");
 669		return 0;
 670	}
 671
 
 
 672	if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
 673		if (!irqd_irq_masked(&desc->irq_data))
 674			mask_irq(desc);
 675		if (!irqd_irq_disabled(&desc->irq_data))
 676			unmask = 1;
 677	}
 678
 679	/* Mask all flags except trigger mode */
 680	flags &= IRQ_TYPE_SENSE_MASK;
 681	ret = chip->irq_set_type(&desc->irq_data, flags);
 682
 683	switch (ret) {
 684	case IRQ_SET_MASK_OK:
 685	case IRQ_SET_MASK_OK_DONE:
 686		irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
 687		irqd_set(&desc->irq_data, flags);
 688
 689	case IRQ_SET_MASK_OK_NOCOPY:
 690		flags = irqd_get_trigger_type(&desc->irq_data);
 691		irq_settings_set_trigger_mask(desc, flags);
 692		irqd_clear(&desc->irq_data, IRQD_LEVEL);
 693		irq_settings_clr_level(desc);
 694		if (flags & IRQ_TYPE_LEVEL_MASK) {
 695			irq_settings_set_level(desc);
 696			irqd_set(&desc->irq_data, IRQD_LEVEL);
 697		}
 698
 699		ret = 0;
 700		break;
 701	default:
 702		pr_err("Setting trigger mode %lu for irq %u failed (%pF)\n",
 703		       flags, irq_desc_get_irq(desc), chip->irq_set_type);
 704	}
 705	if (unmask)
 706		unmask_irq(desc);
 707	return ret;
 708}
 709
 710#ifdef CONFIG_HARDIRQS_SW_RESEND
 711int irq_set_parent(int irq, int parent_irq)
 712{
 713	unsigned long flags;
 714	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
 715
 716	if (!desc)
 717		return -EINVAL;
 718
 719	desc->parent_irq = parent_irq;
 720
 721	irq_put_desc_unlock(desc, flags);
 722	return 0;
 723}
 724EXPORT_SYMBOL_GPL(irq_set_parent);
 725#endif
 726
 727/*
 728 * Default primary interrupt handler for threaded interrupts. Is
 729 * assigned as primary handler when request_threaded_irq is called
 730 * with handler == NULL. Useful for oneshot interrupts.
 731 */
 732static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
 733{
 734	return IRQ_WAKE_THREAD;
 735}
 736
 737/*
 738 * Primary handler for nested threaded interrupts. Should never be
 739 * called.
 740 */
 741static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
 742{
 743	WARN(1, "Primary handler called for nested irq %d\n", irq);
 744	return IRQ_NONE;
 745}
 746
 747static irqreturn_t irq_forced_secondary_handler(int irq, void *dev_id)
 748{
 749	WARN(1, "Secondary action handler called for irq %d\n", irq);
 750	return IRQ_NONE;
 751}
 752
 753static int irq_wait_for_interrupt(struct irqaction *action)
 754{
 755	set_current_state(TASK_INTERRUPTIBLE);
 756
 757	while (!kthread_should_stop()) {
 758
 759		if (test_and_clear_bit(IRQTF_RUNTHREAD,
 760				       &action->thread_flags)) {
 761			__set_current_state(TASK_RUNNING);
 762			return 0;
 763		}
 764		schedule();
 765		set_current_state(TASK_INTERRUPTIBLE);
 766	}
 767	__set_current_state(TASK_RUNNING);
 768	return -1;
 769}
 770
 771/*
 772 * Oneshot interrupts keep the irq line masked until the threaded
 773 * handler finished. unmask if the interrupt has not been disabled and
 774 * is marked MASKED.
 775 */
 776static void irq_finalize_oneshot(struct irq_desc *desc,
 777				 struct irqaction *action)
 778{
 779	if (!(desc->istate & IRQS_ONESHOT) ||
 780	    action->handler == irq_forced_secondary_handler)
 781		return;
 782again:
 783	chip_bus_lock(desc);
 784	raw_spin_lock_irq(&desc->lock);
 785
 786	/*
 787	 * Implausible though it may be we need to protect us against
 788	 * the following scenario:
 789	 *
 790	 * The thread is faster done than the hard interrupt handler
 791	 * on the other CPU. If we unmask the irq line then the
 792	 * interrupt can come in again and masks the line, leaves due
 793	 * to IRQS_INPROGRESS and the irq line is masked forever.
 794	 *
 795	 * This also serializes the state of shared oneshot handlers
 796	 * versus "desc->threads_onehsot |= action->thread_mask;" in
 797	 * irq_wake_thread(). See the comment there which explains the
 798	 * serialization.
 799	 */
 800	if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
 801		raw_spin_unlock_irq(&desc->lock);
 802		chip_bus_sync_unlock(desc);
 803		cpu_relax();
 804		goto again;
 805	}
 806
 807	/*
 808	 * Now check again, whether the thread should run. Otherwise
 809	 * we would clear the threads_oneshot bit of this thread which
 810	 * was just set.
 811	 */
 812	if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
 813		goto out_unlock;
 814
 815	desc->threads_oneshot &= ~action->thread_mask;
 816
 817	if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
 818	    irqd_irq_masked(&desc->irq_data))
 819		unmask_threaded_irq(desc);
 820
 821out_unlock:
 822	raw_spin_unlock_irq(&desc->lock);
 823	chip_bus_sync_unlock(desc);
 824}
 825
 826#ifdef CONFIG_SMP
 827/*
 828 * Check whether we need to change the affinity of the interrupt thread.
 829 */
 830static void
 831irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
 832{
 833	cpumask_var_t mask;
 834	bool valid = true;
 835
 836	if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
 837		return;
 838
 839	/*
 840	 * In case we are out of memory we set IRQTF_AFFINITY again and
 841	 * try again next time
 842	 */
 843	if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
 844		set_bit(IRQTF_AFFINITY, &action->thread_flags);
 845		return;
 846	}
 847
 848	raw_spin_lock_irq(&desc->lock);
 849	/*
 850	 * This code is triggered unconditionally. Check the affinity
 851	 * mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
 852	 */
 853	if (desc->irq_common_data.affinity)
 854		cpumask_copy(mask, desc->irq_common_data.affinity);
 855	else
 856		valid = false;
 857	raw_spin_unlock_irq(&desc->lock);
 858
 859	if (valid)
 860		set_cpus_allowed_ptr(current, mask);
 861	free_cpumask_var(mask);
 862}
 863#else
 864static inline void
 865irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
 866#endif
 867
 868/*
 869 * Interrupts which are not explicitely requested as threaded
 870 * interrupts rely on the implicit bh/preempt disable of the hard irq
 871 * context. So we need to disable bh here to avoid deadlocks and other
 872 * side effects.
 873 */
 874static irqreturn_t
 875irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
 876{
 877	irqreturn_t ret;
 878
 879	local_bh_disable();
 880	ret = action->thread_fn(action->irq, action->dev_id);
 881	irq_finalize_oneshot(desc, action);
 882	local_bh_enable();
 883	return ret;
 884}
 885
 886/*
 887 * Interrupts explicitly requested as threaded interrupts want to be
 888 * preemtible - many of them need to sleep and wait for slow busses to
 889 * complete.
 890 */
 891static irqreturn_t irq_thread_fn(struct irq_desc *desc,
 892		struct irqaction *action)
 893{
 894	irqreturn_t ret;
 895
 896	ret = action->thread_fn(action->irq, action->dev_id);
 897	irq_finalize_oneshot(desc, action);
 898	return ret;
 899}
 900
 901static void wake_threads_waitq(struct irq_desc *desc)
 902{
 903	if (atomic_dec_and_test(&desc->threads_active))
 
 904		wake_up(&desc->wait_for_threads);
 905}
 906
 907static void irq_thread_dtor(struct callback_head *unused)
 908{
 909	struct task_struct *tsk = current;
 910	struct irq_desc *desc;
 911	struct irqaction *action;
 912
 913	if (WARN_ON_ONCE(!(current->flags & PF_EXITING)))
 914		return;
 915
 916	action = kthread_data(tsk);
 917
 918	pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
 919	       tsk->comm, tsk->pid, action->irq);
 920
 921
 922	desc = irq_to_desc(action->irq);
 923	/*
 924	 * If IRQTF_RUNTHREAD is set, we need to decrement
 925	 * desc->threads_active and wake possible waiters.
 926	 */
 927	if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
 928		wake_threads_waitq(desc);
 929
 930	/* Prevent a stale desc->threads_oneshot */
 931	irq_finalize_oneshot(desc, action);
 932}
 933
 934static void irq_wake_secondary(struct irq_desc *desc, struct irqaction *action)
 935{
 936	struct irqaction *secondary = action->secondary;
 937
 938	if (WARN_ON_ONCE(!secondary))
 939		return;
 940
 941	raw_spin_lock_irq(&desc->lock);
 942	__irq_wake_thread(desc, secondary);
 943	raw_spin_unlock_irq(&desc->lock);
 944}
 945
 946/*
 947 * Interrupt handler thread
 948 */
 949static int irq_thread(void *data)
 950{
 951	struct callback_head on_exit_work;
 
 
 
 952	struct irqaction *action = data;
 953	struct irq_desc *desc = irq_to_desc(action->irq);
 954	irqreturn_t (*handler_fn)(struct irq_desc *desc,
 955			struct irqaction *action);
 956
 957	if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
 958					&action->thread_flags))
 959		handler_fn = irq_forced_thread_fn;
 960	else
 961		handler_fn = irq_thread_fn;
 962
 963	init_task_work(&on_exit_work, irq_thread_dtor);
 964	task_work_add(current, &on_exit_work, false);
 965
 966	irq_thread_check_affinity(desc, action);
 
 967
 968	while (!irq_wait_for_interrupt(action)) {
 969		irqreturn_t action_ret;
 970
 971		irq_thread_check_affinity(desc, action);
 972
 973		action_ret = handler_fn(desc, action);
 974		if (action_ret == IRQ_HANDLED)
 975			atomic_inc(&desc->threads_handled);
 976		if (action_ret == IRQ_WAKE_THREAD)
 977			irq_wake_secondary(desc, action);
 978
 979		wake_threads_waitq(desc);
 980	}
 981
 982	/*
 983	 * This is the regular exit path. __free_irq() is stopping the
 984	 * thread via kthread_stop() after calling
 985	 * synchronize_irq(). So neither IRQTF_RUNTHREAD nor the
 986	 * oneshot mask bit can be set. We cannot verify that as we
 987	 * cannot touch the oneshot mask at this point anymore as
 988	 * __setup_irq() might have given out currents thread_mask
 989	 * again.
 990	 */
 991	task_work_cancel(current, irq_thread_dtor);
 992	return 0;
 993}
 994
 995/**
 996 *	irq_wake_thread - wake the irq thread for the action identified by dev_id
 997 *	@irq:		Interrupt line
 998 *	@dev_id:	Device identity for which the thread should be woken
 999 *
1000 */
1001void irq_wake_thread(unsigned int irq, void *dev_id)
1002{
1003	struct irq_desc *desc = irq_to_desc(irq);
1004	struct irqaction *action;
1005	unsigned long flags;
1006
1007	if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1008		return;
1009
1010	raw_spin_lock_irqsave(&desc->lock, flags);
1011	for_each_action_of_desc(desc, action) {
1012		if (action->dev_id == dev_id) {
1013			if (action->thread)
1014				__irq_wake_thread(desc, action);
1015			break;
1016		}
1017	}
1018	raw_spin_unlock_irqrestore(&desc->lock, flags);
1019}
1020EXPORT_SYMBOL_GPL(irq_wake_thread);
1021
1022static int irq_setup_forced_threading(struct irqaction *new)
1023{
1024	if (!force_irqthreads)
1025		return 0;
1026	if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
1027		return 0;
1028
1029	new->flags |= IRQF_ONESHOT;
1030
1031	/*
1032	 * Handle the case where we have a real primary handler and a
1033	 * thread handler. We force thread them as well by creating a
1034	 * secondary action.
1035	 */
1036	if (new->handler != irq_default_primary_handler && new->thread_fn) {
1037		/* Allocate the secondary action */
1038		new->secondary = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1039		if (!new->secondary)
1040			return -ENOMEM;
1041		new->secondary->handler = irq_forced_secondary_handler;
1042		new->secondary->thread_fn = new->thread_fn;
1043		new->secondary->dev_id = new->dev_id;
1044		new->secondary->irq = new->irq;
1045		new->secondary->name = new->name;
1046	}
1047	/* Deal with the primary handler */
1048	set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
1049	new->thread_fn = new->handler;
1050	new->handler = irq_default_primary_handler;
1051	return 0;
1052}
1053
1054static int irq_request_resources(struct irq_desc *desc)
1055{
1056	struct irq_data *d = &desc->irq_data;
1057	struct irq_chip *c = d->chip;
1058
1059	return c->irq_request_resources ? c->irq_request_resources(d) : 0;
1060}
1061
1062static void irq_release_resources(struct irq_desc *desc)
1063{
1064	struct irq_data *d = &desc->irq_data;
1065	struct irq_chip *c = d->chip;
1066
1067	if (c->irq_release_resources)
1068		c->irq_release_resources(d);
1069}
1070
1071static int
1072setup_irq_thread(struct irqaction *new, unsigned int irq, bool secondary)
1073{
1074	struct task_struct *t;
1075	struct sched_param param = {
1076		.sched_priority = MAX_USER_RT_PRIO/2,
1077	};
1078
1079	if (!secondary) {
1080		t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
1081				   new->name);
1082	} else {
1083		t = kthread_create(irq_thread, new, "irq/%d-s-%s", irq,
1084				   new->name);
1085		param.sched_priority -= 1;
1086	}
1087
1088	if (IS_ERR(t))
1089		return PTR_ERR(t);
1090
1091	sched_setscheduler_nocheck(t, SCHED_FIFO, &param);
1092
1093	/*
1094	 * We keep the reference to the task struct even if
1095	 * the thread dies to avoid that the interrupt code
1096	 * references an already freed task_struct.
1097	 */
1098	get_task_struct(t);
1099	new->thread = t;
1100	/*
1101	 * Tell the thread to set its affinity. This is
1102	 * important for shared interrupt handlers as we do
1103	 * not invoke setup_affinity() for the secondary
1104	 * handlers as everything is already set up. Even for
1105	 * interrupts marked with IRQF_NO_BALANCE this is
1106	 * correct as we want the thread to move to the cpu(s)
1107	 * on which the requesting code placed the interrupt.
1108	 */
1109	set_bit(IRQTF_AFFINITY, &new->thread_flags);
1110	return 0;
1111}
1112
1113/*
1114 * Internal function to register an irqaction - typically used to
1115 * allocate special interrupts that are part of the architecture.
1116 */
1117static int
1118__setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
1119{
1120	struct irqaction *old, **old_ptr;
1121	unsigned long flags, thread_mask = 0;
1122	int ret, nested, shared = 0;
1123	cpumask_var_t mask;
1124
1125	if (!desc)
1126		return -EINVAL;
1127
1128	if (desc->irq_data.chip == &no_irq_chip)
1129		return -ENOSYS;
1130	if (!try_module_get(desc->owner))
1131		return -ENODEV;
1132
1133	new->irq = irq;
1134
1135	/*
1136	 * If the trigger type is not specified by the caller,
1137	 * then use the default for this interrupt.
1138	 */
1139	if (!(new->flags & IRQF_TRIGGER_MASK))
1140		new->flags |= irqd_get_trigger_type(&desc->irq_data);
1141
1142	/*
1143	 * Check whether the interrupt nests into another interrupt
1144	 * thread.
1145	 */
1146	nested = irq_settings_is_nested_thread(desc);
1147	if (nested) {
1148		if (!new->thread_fn) {
1149			ret = -EINVAL;
1150			goto out_mput;
1151		}
1152		/*
1153		 * Replace the primary handler which was provided from
1154		 * the driver for non nested interrupt handling by the
1155		 * dummy function which warns when called.
1156		 */
1157		new->handler = irq_nested_primary_handler;
1158	} else {
1159		if (irq_settings_can_thread(desc)) {
1160			ret = irq_setup_forced_threading(new);
1161			if (ret)
1162				goto out_mput;
1163		}
1164	}
1165
1166	/*
1167	 * Create a handler thread when a thread function is supplied
1168	 * and the interrupt does not nest into another interrupt
1169	 * thread.
1170	 */
1171	if (new->thread_fn && !nested) {
1172		ret = setup_irq_thread(new, irq, false);
1173		if (ret)
 
 
 
 
1174			goto out_mput;
1175		if (new->secondary) {
1176			ret = setup_irq_thread(new->secondary, irq, true);
1177			if (ret)
1178				goto out_thread;
1179		}
 
 
 
 
 
 
 
1180	}
1181
1182	if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
1183		ret = -ENOMEM;
1184		goto out_thread;
1185	}
1186
1187	/*
1188	 * Drivers are often written to work w/o knowledge about the
1189	 * underlying irq chip implementation, so a request for a
1190	 * threaded irq without a primary hard irq context handler
1191	 * requires the ONESHOT flag to be set. Some irq chips like
1192	 * MSI based interrupts are per se one shot safe. Check the
1193	 * chip flags, so we can avoid the unmask dance at the end of
1194	 * the threaded handler for those.
1195	 */
1196	if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)
1197		new->flags &= ~IRQF_ONESHOT;
1198
1199	/*
1200	 * The following block of code has to be executed atomically
1201	 */
1202	raw_spin_lock_irqsave(&desc->lock, flags);
1203	old_ptr = &desc->action;
1204	old = *old_ptr;
1205	if (old) {
1206		/*
1207		 * Can't share interrupts unless both agree to and are
1208		 * the same type (level, edge, polarity). So both flag
1209		 * fields must have IRQF_SHARED set and the bits which
1210		 * set the trigger type must match. Also all must
1211		 * agree on ONESHOT.
1212		 */
1213		if (!((old->flags & new->flags) & IRQF_SHARED) ||
1214		    ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
1215		    ((old->flags ^ new->flags) & IRQF_ONESHOT))
1216			goto mismatch;
1217
1218		/* All handlers must agree on per-cpuness */
1219		if ((old->flags & IRQF_PERCPU) !=
1220		    (new->flags & IRQF_PERCPU))
1221			goto mismatch;
1222
1223		/* add new interrupt at end of irq queue */
1224		do {
1225			/*
1226			 * Or all existing action->thread_mask bits,
1227			 * so we can find the next zero bit for this
1228			 * new action.
1229			 */
1230			thread_mask |= old->thread_mask;
1231			old_ptr = &old->next;
1232			old = *old_ptr;
1233		} while (old);
1234		shared = 1;
1235	}
1236
1237	/*
1238	 * Setup the thread mask for this irqaction for ONESHOT. For
1239	 * !ONESHOT irqs the thread mask is 0 so we can avoid a
1240	 * conditional in irq_wake_thread().
1241	 */
1242	if (new->flags & IRQF_ONESHOT) {
1243		/*
1244		 * Unlikely to have 32 resp 64 irqs sharing one line,
1245		 * but who knows.
1246		 */
1247		if (thread_mask == ~0UL) {
1248			ret = -EBUSY;
1249			goto out_mask;
1250		}
1251		/*
1252		 * The thread_mask for the action is or'ed to
1253		 * desc->thread_active to indicate that the
1254		 * IRQF_ONESHOT thread handler has been woken, but not
1255		 * yet finished. The bit is cleared when a thread
1256		 * completes. When all threads of a shared interrupt
1257		 * line have completed desc->threads_active becomes
1258		 * zero and the interrupt line is unmasked. See
1259		 * handle.c:irq_wake_thread() for further information.
1260		 *
1261		 * If no thread is woken by primary (hard irq context)
1262		 * interrupt handlers, then desc->threads_active is
1263		 * also checked for zero to unmask the irq line in the
1264		 * affected hard irq flow handlers
1265		 * (handle_[fasteoi|level]_irq).
1266		 *
1267		 * The new action gets the first zero bit of
1268		 * thread_mask assigned. See the loop above which or's
1269		 * all existing action->thread_mask bits.
1270		 */
1271		new->thread_mask = 1 << ffz(thread_mask);
1272
1273	} else if (new->handler == irq_default_primary_handler &&
1274		   !(desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)) {
1275		/*
1276		 * The interrupt was requested with handler = NULL, so
1277		 * we use the default primary handler for it. But it
1278		 * does not have the oneshot flag set. In combination
1279		 * with level interrupts this is deadly, because the
1280		 * default primary handler just wakes the thread, then
1281		 * the irq lines is reenabled, but the device still
1282		 * has the level irq asserted. Rinse and repeat....
1283		 *
1284		 * While this works for edge type interrupts, we play
1285		 * it safe and reject unconditionally because we can't
1286		 * say for sure which type this interrupt really
1287		 * has. The type flags are unreliable as the
1288		 * underlying chip implementation can override them.
1289		 */
1290		pr_err("Threaded irq requested with handler=NULL and !ONESHOT for irq %d\n",
1291		       irq);
1292		ret = -EINVAL;
1293		goto out_mask;
1294	}
1295
1296	if (!shared) {
1297		ret = irq_request_resources(desc);
1298		if (ret) {
1299			pr_err("Failed to request resources for %s (irq %d) on irqchip %s\n",
1300			       new->name, irq, desc->irq_data.chip->name);
1301			goto out_mask;
1302		}
1303
1304		init_waitqueue_head(&desc->wait_for_threads);
1305
1306		/* Setup the type (level, edge polarity) if configured: */
1307		if (new->flags & IRQF_TRIGGER_MASK) {
1308			ret = __irq_set_trigger(desc,
1309						new->flags & IRQF_TRIGGER_MASK);
1310
1311			if (ret)
1312				goto out_mask;
1313		}
1314
1315		desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1316				  IRQS_ONESHOT | IRQS_WAITING);
1317		irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1318
1319		if (new->flags & IRQF_PERCPU) {
1320			irqd_set(&desc->irq_data, IRQD_PER_CPU);
1321			irq_settings_set_per_cpu(desc);
1322		}
1323
1324		if (new->flags & IRQF_ONESHOT)
1325			desc->istate |= IRQS_ONESHOT;
1326
1327		if (irq_settings_can_autoenable(desc))
1328			irq_startup(desc, true);
1329		else
1330			/* Undo nested disables: */
1331			desc->depth = 1;
1332
1333		/* Exclude IRQ from balancing if requested */
1334		if (new->flags & IRQF_NOBALANCING) {
1335			irq_settings_set_no_balancing(desc);
1336			irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1337		}
1338
1339		/* Set default affinity mask once everything is setup */
1340		setup_affinity(desc, mask);
1341
1342	} else if (new->flags & IRQF_TRIGGER_MASK) {
1343		unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1344		unsigned int omsk = irqd_get_trigger_type(&desc->irq_data);
1345
1346		if (nmsk != omsk)
1347			/* hope the handler works with current  trigger mode */
1348			pr_warn("irq %d uses trigger mode %u; requested %u\n",
1349				irq, omsk, nmsk);
1350	}
1351
 
1352	*old_ptr = new;
1353
1354	irq_pm_install_action(desc, new);
1355
1356	/* Reset broken irq detection when installing new handler */
1357	desc->irq_count = 0;
1358	desc->irqs_unhandled = 0;
1359
1360	/*
1361	 * Check whether we disabled the irq via the spurious handler
1362	 * before. Reenable it and give it another chance.
1363	 */
1364	if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1365		desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1366		__enable_irq(desc);
1367	}
1368
1369	raw_spin_unlock_irqrestore(&desc->lock, flags);
1370
1371	/*
1372	 * Strictly no need to wake it up, but hung_task complains
1373	 * when no hard interrupt wakes the thread up.
1374	 */
1375	if (new->thread)
1376		wake_up_process(new->thread);
1377	if (new->secondary)
1378		wake_up_process(new->secondary->thread);
1379
1380	register_irq_proc(irq, desc);
1381	new->dir = NULL;
1382	register_handler_proc(irq, new);
1383	free_cpumask_var(mask);
1384
1385	return 0;
1386
1387mismatch:
1388	if (!(new->flags & IRQF_PROBE_SHARED)) {
1389		pr_err("Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
1390		       irq, new->flags, new->name, old->flags, old->name);
1391#ifdef CONFIG_DEBUG_SHIRQ
1392		dump_stack();
1393#endif
1394	}
1395	ret = -EBUSY;
1396
1397out_mask:
1398	raw_spin_unlock_irqrestore(&desc->lock, flags);
1399	free_cpumask_var(mask);
1400
1401out_thread:
1402	if (new->thread) {
1403		struct task_struct *t = new->thread;
1404
1405		new->thread = NULL;
1406		kthread_stop(t);
1407		put_task_struct(t);
1408	}
1409	if (new->secondary && new->secondary->thread) {
1410		struct task_struct *t = new->secondary->thread;
1411
1412		new->secondary->thread = NULL;
1413		kthread_stop(t);
1414		put_task_struct(t);
1415	}
1416out_mput:
1417	module_put(desc->owner);
1418	return ret;
1419}
1420
1421/**
1422 *	setup_irq - setup an interrupt
1423 *	@irq: Interrupt line to setup
1424 *	@act: irqaction for the interrupt
1425 *
1426 * Used to statically setup interrupts in the early boot process.
1427 */
1428int setup_irq(unsigned int irq, struct irqaction *act)
1429{
1430	int retval;
1431	struct irq_desc *desc = irq_to_desc(irq);
1432
1433	if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1434		return -EINVAL;
1435
1436	retval = irq_chip_pm_get(&desc->irq_data);
1437	if (retval < 0)
1438		return retval;
1439
1440	chip_bus_lock(desc);
1441	retval = __setup_irq(irq, desc, act);
1442	chip_bus_sync_unlock(desc);
1443
1444	if (retval)
1445		irq_chip_pm_put(&desc->irq_data);
1446
1447	return retval;
1448}
1449EXPORT_SYMBOL_GPL(setup_irq);
1450
1451/*
1452 * Internal function to unregister an irqaction - used to free
1453 * regular and special interrupts that are part of the architecture.
1454 */
1455static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
1456{
1457	struct irq_desc *desc = irq_to_desc(irq);
1458	struct irqaction *action, **action_ptr;
1459	unsigned long flags;
1460
1461	WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1462
1463	if (!desc)
1464		return NULL;
1465
1466	chip_bus_lock(desc);
1467	raw_spin_lock_irqsave(&desc->lock, flags);
1468
1469	/*
1470	 * There can be multiple actions per IRQ descriptor, find the right
1471	 * one based on the dev_id:
1472	 */
1473	action_ptr = &desc->action;
1474	for (;;) {
1475		action = *action_ptr;
1476
1477		if (!action) {
1478			WARN(1, "Trying to free already-free IRQ %d\n", irq);
1479			raw_spin_unlock_irqrestore(&desc->lock, flags);
1480			chip_bus_sync_unlock(desc);
1481			return NULL;
1482		}
1483
1484		if (action->dev_id == dev_id)
1485			break;
1486		action_ptr = &action->next;
1487	}
1488
1489	/* Found it - now remove it from the list of entries: */
1490	*action_ptr = action->next;
1491
1492	irq_pm_remove_action(desc, action);
1493
1494	/* If this was the last handler, shut down the IRQ line: */
1495	if (!desc->action) {
1496		irq_settings_clr_disable_unlazy(desc);
1497		irq_shutdown(desc);
1498		irq_release_resources(desc);
1499	}
1500
1501#ifdef CONFIG_SMP
1502	/* make sure affinity_hint is cleaned up */
1503	if (WARN_ON_ONCE(desc->affinity_hint))
1504		desc->affinity_hint = NULL;
1505#endif
1506
1507	raw_spin_unlock_irqrestore(&desc->lock, flags);
1508	chip_bus_sync_unlock(desc);
1509
1510	unregister_handler_proc(irq, action);
1511
1512	/* Make sure it's not being used on another CPU: */
1513	synchronize_irq(irq);
1514
1515#ifdef CONFIG_DEBUG_SHIRQ
1516	/*
1517	 * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1518	 * event to happen even now it's being freed, so let's make sure that
1519	 * is so by doing an extra call to the handler ....
1520	 *
1521	 * ( We do this after actually deregistering it, to make sure that a
1522	 *   'real' IRQ doesn't run in * parallel with our fake. )
1523	 */
1524	if (action->flags & IRQF_SHARED) {
1525		local_irq_save(flags);
1526		action->handler(irq, dev_id);
1527		local_irq_restore(flags);
1528	}
1529#endif
1530
1531	if (action->thread) {
1532		kthread_stop(action->thread);
1533		put_task_struct(action->thread);
1534		if (action->secondary && action->secondary->thread) {
1535			kthread_stop(action->secondary->thread);
1536			put_task_struct(action->secondary->thread);
1537		}
1538	}
1539
1540	irq_chip_pm_put(&desc->irq_data);
1541	module_put(desc->owner);
1542	kfree(action->secondary);
1543	return action;
1544}
1545
1546/**
1547 *	remove_irq - free an interrupt
1548 *	@irq: Interrupt line to free
1549 *	@act: irqaction for the interrupt
1550 *
1551 * Used to remove interrupts statically setup by the early boot process.
1552 */
1553void remove_irq(unsigned int irq, struct irqaction *act)
1554{
1555	struct irq_desc *desc = irq_to_desc(irq);
1556
1557	if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1558	    __free_irq(irq, act->dev_id);
1559}
1560EXPORT_SYMBOL_GPL(remove_irq);
1561
1562/**
1563 *	free_irq - free an interrupt allocated with request_irq
1564 *	@irq: Interrupt line to free
1565 *	@dev_id: Device identity to free
1566 *
1567 *	Remove an interrupt handler. The handler is removed and if the
1568 *	interrupt line is no longer in use by any driver it is disabled.
1569 *	On a shared IRQ the caller must ensure the interrupt is disabled
1570 *	on the card it drives before calling this function. The function
1571 *	does not return until any executing interrupts for this IRQ
1572 *	have completed.
1573 *
1574 *	This function must not be called from interrupt context.
1575 */
1576void free_irq(unsigned int irq, void *dev_id)
1577{
1578	struct irq_desc *desc = irq_to_desc(irq);
1579
1580	if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1581		return;
1582
1583#ifdef CONFIG_SMP
1584	if (WARN_ON(desc->affinity_notify))
1585		desc->affinity_notify = NULL;
1586#endif
1587
 
1588	kfree(__free_irq(irq, dev_id));
 
1589}
1590EXPORT_SYMBOL(free_irq);
1591
1592/**
1593 *	request_threaded_irq - allocate an interrupt line
1594 *	@irq: Interrupt line to allocate
1595 *	@handler: Function to be called when the IRQ occurs.
1596 *		  Primary handler for threaded interrupts
1597 *		  If NULL and thread_fn != NULL the default
1598 *		  primary handler is installed
1599 *	@thread_fn: Function called from the irq handler thread
1600 *		    If NULL, no irq thread is created
1601 *	@irqflags: Interrupt type flags
1602 *	@devname: An ascii name for the claiming device
1603 *	@dev_id: A cookie passed back to the handler function
1604 *
1605 *	This call allocates interrupt resources and enables the
1606 *	interrupt line and IRQ handling. From the point this
1607 *	call is made your handler function may be invoked. Since
1608 *	your handler function must clear any interrupt the board
1609 *	raises, you must take care both to initialise your hardware
1610 *	and to set up the interrupt handler in the right order.
1611 *
1612 *	If you want to set up a threaded irq handler for your device
1613 *	then you need to supply @handler and @thread_fn. @handler is
1614 *	still called in hard interrupt context and has to check
1615 *	whether the interrupt originates from the device. If yes it
1616 *	needs to disable the interrupt on the device and return
1617 *	IRQ_WAKE_THREAD which will wake up the handler thread and run
1618 *	@thread_fn. This split handler design is necessary to support
1619 *	shared interrupts.
1620 *
1621 *	Dev_id must be globally unique. Normally the address of the
1622 *	device data structure is used as the cookie. Since the handler
1623 *	receives this value it makes sense to use it.
1624 *
1625 *	If your interrupt is shared you must pass a non NULL dev_id
1626 *	as this is required when freeing the interrupt.
1627 *
1628 *	Flags:
1629 *
1630 *	IRQF_SHARED		Interrupt is shared
1631 *	IRQF_TRIGGER_*		Specify active edge(s) or level
1632 *
1633 */
1634int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1635			 irq_handler_t thread_fn, unsigned long irqflags,
1636			 const char *devname, void *dev_id)
1637{
1638	struct irqaction *action;
1639	struct irq_desc *desc;
1640	int retval;
1641
1642	if (irq == IRQ_NOTCONNECTED)
1643		return -ENOTCONN;
1644
1645	/*
1646	 * Sanity-check: shared interrupts must pass in a real dev-ID,
1647	 * otherwise we'll have trouble later trying to figure out
1648	 * which interrupt is which (messes up the interrupt freeing
1649	 * logic etc).
1650	 *
1651	 * Also IRQF_COND_SUSPEND only makes sense for shared interrupts and
1652	 * it cannot be set along with IRQF_NO_SUSPEND.
1653	 */
1654	if (((irqflags & IRQF_SHARED) && !dev_id) ||
1655	    (!(irqflags & IRQF_SHARED) && (irqflags & IRQF_COND_SUSPEND)) ||
1656	    ((irqflags & IRQF_NO_SUSPEND) && (irqflags & IRQF_COND_SUSPEND)))
1657		return -EINVAL;
1658
1659	desc = irq_to_desc(irq);
1660	if (!desc)
1661		return -EINVAL;
1662
1663	if (!irq_settings_can_request(desc) ||
1664	    WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1665		return -EINVAL;
1666
1667	if (!handler) {
1668		if (!thread_fn)
1669			return -EINVAL;
1670		handler = irq_default_primary_handler;
1671	}
1672
1673	action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1674	if (!action)
1675		return -ENOMEM;
1676
1677	action->handler = handler;
1678	action->thread_fn = thread_fn;
1679	action->flags = irqflags;
1680	action->name = devname;
1681	action->dev_id = dev_id;
1682
1683	retval = irq_chip_pm_get(&desc->irq_data);
1684	if (retval < 0) {
1685		kfree(action);
1686		return retval;
1687	}
1688
1689	chip_bus_lock(desc);
1690	retval = __setup_irq(irq, desc, action);
1691	chip_bus_sync_unlock(desc);
1692
1693	if (retval) {
1694		irq_chip_pm_put(&desc->irq_data);
1695		kfree(action->secondary);
1696		kfree(action);
1697	}
1698
1699#ifdef CONFIG_DEBUG_SHIRQ_FIXME
1700	if (!retval && (irqflags & IRQF_SHARED)) {
1701		/*
1702		 * It's a shared IRQ -- the driver ought to be prepared for it
1703		 * to happen immediately, so let's make sure....
1704		 * We disable the irq to make sure that a 'real' IRQ doesn't
1705		 * run in parallel with our fake.
1706		 */
1707		unsigned long flags;
1708
1709		disable_irq(irq);
1710		local_irq_save(flags);
1711
1712		handler(irq, dev_id);
1713
1714		local_irq_restore(flags);
1715		enable_irq(irq);
1716	}
1717#endif
1718	return retval;
1719}
1720EXPORT_SYMBOL(request_threaded_irq);
1721
1722/**
1723 *	request_any_context_irq - allocate an interrupt line
1724 *	@irq: Interrupt line to allocate
1725 *	@handler: Function to be called when the IRQ occurs.
1726 *		  Threaded handler for threaded interrupts.
1727 *	@flags: Interrupt type flags
1728 *	@name: An ascii name for the claiming device
1729 *	@dev_id: A cookie passed back to the handler function
1730 *
1731 *	This call allocates interrupt resources and enables the
1732 *	interrupt line and IRQ handling. It selects either a
1733 *	hardirq or threaded handling method depending on the
1734 *	context.
1735 *
1736 *	On failure, it returns a negative value. On success,
1737 *	it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1738 */
1739int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1740			    unsigned long flags, const char *name, void *dev_id)
1741{
1742	struct irq_desc *desc;
1743	int ret;
1744
1745	if (irq == IRQ_NOTCONNECTED)
1746		return -ENOTCONN;
1747
1748	desc = irq_to_desc(irq);
1749	if (!desc)
1750		return -EINVAL;
1751
1752	if (irq_settings_is_nested_thread(desc)) {
1753		ret = request_threaded_irq(irq, NULL, handler,
1754					   flags, name, dev_id);
1755		return !ret ? IRQC_IS_NESTED : ret;
1756	}
1757
1758	ret = request_irq(irq, handler, flags, name, dev_id);
1759	return !ret ? IRQC_IS_HARDIRQ : ret;
1760}
1761EXPORT_SYMBOL_GPL(request_any_context_irq);
1762
1763void enable_percpu_irq(unsigned int irq, unsigned int type)
1764{
1765	unsigned int cpu = smp_processor_id();
1766	unsigned long flags;
1767	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1768
1769	if (!desc)
1770		return;
1771
1772	/*
1773	 * If the trigger type is not specified by the caller, then
1774	 * use the default for this interrupt.
1775	 */
1776	type &= IRQ_TYPE_SENSE_MASK;
1777	if (type == IRQ_TYPE_NONE)
1778		type = irqd_get_trigger_type(&desc->irq_data);
1779
1780	if (type != IRQ_TYPE_NONE) {
1781		int ret;
1782
1783		ret = __irq_set_trigger(desc, type);
1784
1785		if (ret) {
1786			WARN(1, "failed to set type for IRQ%d\n", irq);
1787			goto out;
1788		}
1789	}
1790
1791	irq_percpu_enable(desc, cpu);
1792out:
1793	irq_put_desc_unlock(desc, flags);
1794}
1795EXPORT_SYMBOL_GPL(enable_percpu_irq);
1796
1797/**
1798 * irq_percpu_is_enabled - Check whether the per cpu irq is enabled
1799 * @irq:	Linux irq number to check for
1800 *
1801 * Must be called from a non migratable context. Returns the enable
1802 * state of a per cpu interrupt on the current cpu.
1803 */
1804bool irq_percpu_is_enabled(unsigned int irq)
1805{
1806	unsigned int cpu = smp_processor_id();
1807	struct irq_desc *desc;
1808	unsigned long flags;
1809	bool is_enabled;
1810
1811	desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1812	if (!desc)
1813		return false;
1814
1815	is_enabled = cpumask_test_cpu(cpu, desc->percpu_enabled);
1816	irq_put_desc_unlock(desc, flags);
1817
1818	return is_enabled;
1819}
1820EXPORT_SYMBOL_GPL(irq_percpu_is_enabled);
1821
1822void disable_percpu_irq(unsigned int irq)
1823{
1824	unsigned int cpu = smp_processor_id();
1825	unsigned long flags;
1826	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1827
1828	if (!desc)
1829		return;
1830
1831	irq_percpu_disable(desc, cpu);
1832	irq_put_desc_unlock(desc, flags);
1833}
1834EXPORT_SYMBOL_GPL(disable_percpu_irq);
1835
1836/*
1837 * Internal function to unregister a percpu irqaction.
1838 */
1839static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1840{
1841	struct irq_desc *desc = irq_to_desc(irq);
1842	struct irqaction *action;
1843	unsigned long flags;
1844
1845	WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1846
1847	if (!desc)
1848		return NULL;
1849
1850	raw_spin_lock_irqsave(&desc->lock, flags);
1851
1852	action = desc->action;
1853	if (!action || action->percpu_dev_id != dev_id) {
1854		WARN(1, "Trying to free already-free IRQ %d\n", irq);
1855		goto bad;
1856	}
1857
1858	if (!cpumask_empty(desc->percpu_enabled)) {
1859		WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
1860		     irq, cpumask_first(desc->percpu_enabled));
1861		goto bad;
1862	}
1863
1864	/* Found it - now remove it from the list of entries: */
1865	desc->action = NULL;
1866
1867	raw_spin_unlock_irqrestore(&desc->lock, flags);
1868
1869	unregister_handler_proc(irq, action);
1870
1871	irq_chip_pm_put(&desc->irq_data);
1872	module_put(desc->owner);
1873	return action;
1874
1875bad:
1876	raw_spin_unlock_irqrestore(&desc->lock, flags);
1877	return NULL;
1878}
1879
1880/**
1881 *	remove_percpu_irq - free a per-cpu interrupt
1882 *	@irq: Interrupt line to free
1883 *	@act: irqaction for the interrupt
1884 *
1885 * Used to remove interrupts statically setup by the early boot process.
1886 */
1887void remove_percpu_irq(unsigned int irq, struct irqaction *act)
1888{
1889	struct irq_desc *desc = irq_to_desc(irq);
1890
1891	if (desc && irq_settings_is_per_cpu_devid(desc))
1892	    __free_percpu_irq(irq, act->percpu_dev_id);
1893}
1894
1895/**
1896 *	free_percpu_irq - free an interrupt allocated with request_percpu_irq
1897 *	@irq: Interrupt line to free
1898 *	@dev_id: Device identity to free
1899 *
1900 *	Remove a percpu interrupt handler. The handler is removed, but
1901 *	the interrupt line is not disabled. This must be done on each
1902 *	CPU before calling this function. The function does not return
1903 *	until any executing interrupts for this IRQ have completed.
1904 *
1905 *	This function must not be called from interrupt context.
1906 */
1907void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1908{
1909	struct irq_desc *desc = irq_to_desc(irq);
1910
1911	if (!desc || !irq_settings_is_per_cpu_devid(desc))
1912		return;
1913
1914	chip_bus_lock(desc);
1915	kfree(__free_percpu_irq(irq, dev_id));
1916	chip_bus_sync_unlock(desc);
1917}
1918EXPORT_SYMBOL_GPL(free_percpu_irq);
1919
1920/**
1921 *	setup_percpu_irq - setup a per-cpu interrupt
1922 *	@irq: Interrupt line to setup
1923 *	@act: irqaction for the interrupt
1924 *
1925 * Used to statically setup per-cpu interrupts in the early boot process.
1926 */
1927int setup_percpu_irq(unsigned int irq, struct irqaction *act)
1928{
1929	struct irq_desc *desc = irq_to_desc(irq);
1930	int retval;
1931
1932	if (!desc || !irq_settings_is_per_cpu_devid(desc))
1933		return -EINVAL;
1934
1935	retval = irq_chip_pm_get(&desc->irq_data);
1936	if (retval < 0)
1937		return retval;
1938
1939	chip_bus_lock(desc);
1940	retval = __setup_irq(irq, desc, act);
1941	chip_bus_sync_unlock(desc);
1942
1943	if (retval)
1944		irq_chip_pm_put(&desc->irq_data);
1945
1946	return retval;
1947}
1948
1949/**
1950 *	request_percpu_irq - allocate a percpu interrupt line
1951 *	@irq: Interrupt line to allocate
1952 *	@handler: Function to be called when the IRQ occurs.
1953 *	@devname: An ascii name for the claiming device
1954 *	@dev_id: A percpu cookie passed back to the handler function
1955 *
1956 *	This call allocates interrupt resources and enables the
1957 *	interrupt on the local CPU. If the interrupt is supposed to be
1958 *	enabled on other CPUs, it has to be done on each CPU using
1959 *	enable_percpu_irq().
1960 *
1961 *	Dev_id must be globally unique. It is a per-cpu variable, and
1962 *	the handler gets called with the interrupted CPU's instance of
1963 *	that variable.
1964 */
1965int request_percpu_irq(unsigned int irq, irq_handler_t handler,
1966		       const char *devname, void __percpu *dev_id)
1967{
1968	struct irqaction *action;
1969	struct irq_desc *desc;
1970	int retval;
1971
1972	if (!dev_id)
1973		return -EINVAL;
1974
1975	desc = irq_to_desc(irq);
1976	if (!desc || !irq_settings_can_request(desc) ||
1977	    !irq_settings_is_per_cpu_devid(desc))
1978		return -EINVAL;
1979
1980	action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1981	if (!action)
1982		return -ENOMEM;
1983
1984	action->handler = handler;
1985	action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
1986	action->name = devname;
1987	action->percpu_dev_id = dev_id;
1988
1989	retval = irq_chip_pm_get(&desc->irq_data);
1990	if (retval < 0) {
1991		kfree(action);
1992		return retval;
1993	}
1994
1995	chip_bus_lock(desc);
1996	retval = __setup_irq(irq, desc, action);
1997	chip_bus_sync_unlock(desc);
1998
1999	if (retval) {
2000		irq_chip_pm_put(&desc->irq_data);
2001		kfree(action);
2002	}
2003
2004	return retval;
2005}
2006EXPORT_SYMBOL_GPL(request_percpu_irq);
2007
2008/**
2009 *	irq_get_irqchip_state - returns the irqchip state of a interrupt.
2010 *	@irq: Interrupt line that is forwarded to a VM
2011 *	@which: One of IRQCHIP_STATE_* the caller wants to know about
2012 *	@state: a pointer to a boolean where the state is to be storeed
2013 *
2014 *	This call snapshots the internal irqchip state of an
2015 *	interrupt, returning into @state the bit corresponding to
2016 *	stage @which
2017 *
2018 *	This function should be called with preemption disabled if the
2019 *	interrupt controller has per-cpu registers.
2020 */
2021int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
2022			  bool *state)
2023{
2024	struct irq_desc *desc;
2025	struct irq_data *data;
2026	struct irq_chip *chip;
2027	unsigned long flags;
2028	int err = -EINVAL;
2029
2030	desc = irq_get_desc_buslock(irq, &flags, 0);
2031	if (!desc)
2032		return err;
2033
2034	data = irq_desc_get_irq_data(desc);
2035
2036	do {
2037		chip = irq_data_get_irq_chip(data);
2038		if (chip->irq_get_irqchip_state)
2039			break;
2040#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
2041		data = data->parent_data;
2042#else
2043		data = NULL;
2044#endif
2045	} while (data);
2046
2047	if (data)
2048		err = chip->irq_get_irqchip_state(data, which, state);
2049
2050	irq_put_desc_busunlock(desc, flags);
2051	return err;
2052}
2053EXPORT_SYMBOL_GPL(irq_get_irqchip_state);
2054
2055/**
2056 *	irq_set_irqchip_state - set the state of a forwarded interrupt.
2057 *	@irq: Interrupt line that is forwarded to a VM
2058 *	@which: State to be restored (one of IRQCHIP_STATE_*)
2059 *	@val: Value corresponding to @which
2060 *
2061 *	This call sets the internal irqchip state of an interrupt,
2062 *	depending on the value of @which.
2063 *
2064 *	This function should be called with preemption disabled if the
2065 *	interrupt controller has per-cpu registers.
2066 */
2067int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
2068			  bool val)
2069{
2070	struct irq_desc *desc;
2071	struct irq_data *data;
2072	struct irq_chip *chip;
2073	unsigned long flags;
2074	int err = -EINVAL;
2075
2076	desc = irq_get_desc_buslock(irq, &flags, 0);
2077	if (!desc)
2078		return err;
2079
2080	data = irq_desc_get_irq_data(desc);
2081
2082	do {
2083		chip = irq_data_get_irq_chip(data);
2084		if (chip->irq_set_irqchip_state)
2085			break;
2086#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
2087		data = data->parent_data;
2088#else
2089		data = NULL;
2090#endif
2091	} while (data);
2092
2093	if (data)
2094		err = chip->irq_set_irqchip_state(data, which, val);
2095
2096	irq_put_desc_busunlock(desc, flags);
2097	return err;
2098}
2099EXPORT_SYMBOL_GPL(irq_set_irqchip_state);