/arch/arm/kernel/irq.c

   1/*
   2 *  linux/arch/arm/kernel/irq.c
   3 *
   4 *  Copyright (C) 1992 Linus Torvalds
   5 *  Modifications for ARM processor Copyright (C) 1995-2000 Russell King.
   6 *
   7 * This program is free software; you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public License version 2 as
   9 * published by the Free Software Foundation.
  10 *
  11 *  This file contains the code used by various IRQ handling routines:
  12 *  asking for different IRQ's should be done through these routines
  13 *  instead of just grabbing them. Thus setups with different IRQ numbers
  14 *  shouldn't result in any weird surprises, and installing new handlers
  15 *  should be easier.
  16 *
  17 *  IRQ's are in fact implemented a bit like signal handlers for the kernel.
  18 *  Naturally it's not a 1:1 relation, but there are similarities.
  19 */
  20#include <linux/config.h>
  21#include <linux/kernel_stat.h>
  22#include <linux/module.h>
  23#include <linux/signal.h>
  24#include <linux/ioport.h>
  25#include <linux/interrupt.h>
  26#include <linux/ptrace.h>
  27#include <linux/slab.h>
  28#include <linux/random.h>
  29#include <linux/smp.h>
  30#include <linux/init.h>
  31#include <linux/seq_file.h>
  32#include <linux/errno.h>
  33#include <linux/list.h>
  34#include <linux/kallsyms.h>
  35#include <linux/proc_fs.h>
  36
  37#include <asm/irq.h>
  38#include <asm/system.h>
  39#include <asm/mach/irq.h>
  40
  41/*
  42 * Maximum IRQ count.  Currently, this is arbitary.  However, it should
  43 * not be set too low to prevent false triggering.  Conversely, if it
  44 * is set too high, then you could miss a stuck IRQ.
  45 *
  46 * Maybe we ought to set a timer and re-enable the IRQ at a later time?
  47 */
  48#define MAX_IRQ_CNT	100000
  49
  50static int noirqdebug;
  51static volatile unsigned long irq_err_count;
  52static DEFINE_SPINLOCK(irq_controller_lock);
  53static LIST_HEAD(irq_pending);
  54
  55struct irqdesc irq_desc[NR_IRQS];
  56void (*init_arch_irq)(void) __initdata = NULL;
  57
  58/*
  59 * No architecture-specific irq_finish function defined in arm/arch/irqs.h.
  60 */
  61#ifndef irq_finish
  62#define irq_finish(irq) do { } while (0)
  63#endif
  64
  65/*
  66 * Dummy mask/unmask handler
  67 */
  68void dummy_mask_unmask_irq(unsigned int irq)
  69{
  70}
  71
  72irqreturn_t no_action(int irq, void *dev_id, struct pt_regs *regs)
  73{
  74	return IRQ_NONE;
  75}
  76
  77void do_bad_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
  78{
  79	irq_err_count += 1;
  80	printk(KERN_ERR "IRQ: spurious interrupt %d\n", irq);
  81}
  82
  83static struct irqchip bad_chip = {
  84	.ack	= dummy_mask_unmask_irq,
  85	.mask	= dummy_mask_unmask_irq,
  86	.unmask = dummy_mask_unmask_irq,
  87};
  88
  89static struct irqdesc bad_irq_desc = {
  90	.chip		= &bad_chip,
  91	.handle		= do_bad_IRQ,
  92	.pend		= LIST_HEAD_INIT(bad_irq_desc.pend),
  93	.disable_depth	= 1,
  94};
  95
  96#ifdef CONFIG_SMP
  97void synchronize_irq(unsigned int irq)
  98{
  99	struct irqdesc *desc = irq_desc + irq;
 100
 101	while (desc->running)
 102		barrier();
 103}
 104EXPORT_SYMBOL(synchronize_irq);
 105
 106#define smp_set_running(desc)	do { desc->running = 1; } while (0)
 107#define smp_clear_running(desc)	do { desc->running = 0; } while (0)
 108#else
 109#define smp_set_running(desc)	do { } while (0)
 110#define smp_clear_running(desc)	do { } while (0)
 111#endif
 112
 113/**
 114 *	disable_irq_nosync - disable an irq without waiting
 115 *	@irq: Interrupt to disable
 116 *
 117 *	Disable the selected interrupt line.  Enables and disables
 118 *	are nested.  We do this lazily.
 119 *
 120 *	This function may be called from IRQ context.
 121 */
 122void disable_irq_nosync(unsigned int irq)
 123{
 124	struct irqdesc *desc = irq_desc + irq;
 125	unsigned long flags;
 126
 127	spin_lock_irqsave(&irq_controller_lock, flags);
 128	desc->disable_depth++;
 129	list_del_init(&desc->pend);
 130	spin_unlock_irqrestore(&irq_controller_lock, flags);
 131}
 132EXPORT_SYMBOL(disable_irq_nosync);
 133
 134/**
 135 *	disable_irq - disable an irq and wait for completion
 136 *	@irq: Interrupt to disable
 137 *
 138 *	Disable the selected interrupt line.  Enables and disables
 139 *	are nested.  This functions waits for any pending IRQ
 140 *	handlers for this interrupt to complete before returning.
 141 *	If you use this function while holding a resource the IRQ
 142 *	handler may need you will deadlock.
 143 *
 144 *	This function may be called - with care - from IRQ context.
 145 */
 146void disable_irq(unsigned int irq)
 147{
 148	struct irqdesc *desc = irq_desc + irq;
 149
 150	disable_irq_nosync(irq);
 151	if (desc->action)
 152		synchronize_irq(irq);
 153}
 154EXPORT_SYMBOL(disable_irq);
 155
 156/**
 157 *	enable_irq - enable interrupt handling on an irq
 158 *	@irq: Interrupt to enable
 159 *
 160 *	Re-enables the processing of interrupts on this IRQ line.
 161 *	Note that this may call the interrupt handler, so you may
 162 *	get unexpected results if you hold IRQs disabled.
 163 *
 164 *	This function may be called from IRQ context.
 165 */
 166void enable_irq(unsigned int irq)
 167{
 168	struct irqdesc *desc = irq_desc + irq;
 169	unsigned long flags;
 170
 171	spin_lock_irqsave(&irq_controller_lock, flags);
 172	if (unlikely(!desc->disable_depth)) {
 173		printk("enable_irq(%u) unbalanced from %p\n", irq,
 174			__builtin_return_address(0));
 175	} else if (!--desc->disable_depth) {
 176		desc->probing = 0;
 177		desc->chip->unmask(irq);
 178
 179		/*
 180		 * If the interrupt is waiting to be processed,
 181		 * try to re-run it.  We can't directly run it
 182		 * from here since the caller might be in an
 183		 * interrupt-protected region.
 184		 */
 185		if (desc->pending && list_empty(&desc->pend)) {
 186			desc->pending = 0;
 187			if (!desc->chip->retrigger ||
 188			    desc->chip->retrigger(irq))
 189				list_add(&desc->pend, &irq_pending);
 190		}
 191	}
 192	spin_unlock_irqrestore(&irq_controller_lock, flags);
 193}
 194EXPORT_SYMBOL(enable_irq);
 195
 196/*
 197 * Enable wake on selected irq
 198 */
 199void enable_irq_wake(unsigned int irq)
 200{
 201	struct irqdesc *desc = irq_desc + irq;
 202	unsigned long flags;
 203
 204	spin_lock_irqsave(&irq_controller_lock, flags);
 205	if (desc->chip->wake)
 206		desc->chip->wake(irq, 1);
 207	spin_unlock_irqrestore(&irq_controller_lock, flags);
 208}
 209EXPORT_SYMBOL(enable_irq_wake);
 210
 211void disable_irq_wake(unsigned int irq)
 212{
 213	struct irqdesc *desc = irq_desc + irq;
 214	unsigned long flags;
 215
 216	spin_lock_irqsave(&irq_controller_lock, flags);
 217	if (desc->chip->wake)
 218		desc->chip->wake(irq, 0);
 219	spin_unlock_irqrestore(&irq_controller_lock, flags);
 220}
 221EXPORT_SYMBOL(disable_irq_wake);
 222
 223int show_interrupts(struct seq_file *p, void *v)
 224{
 225	int i = *(loff_t *) v, cpu;
 226	struct irqaction * action;
 227	unsigned long flags;
 228
 229	if (i == 0) {
 230		char cpuname[12];
 231
 232		seq_printf(p, "    ");
 233		for_each_present_cpu(cpu) {
 234			sprintf(cpuname, "CPU%d", cpu);
 235			seq_printf(p, " %10s", cpuname);
 236		}
 237		seq_putc(p, '\n');
 238	}
 239
 240	if (i < NR_IRQS) {
 241		spin_lock_irqsave(&irq_controller_lock, flags);
 242	    	action = irq_desc[i].action;
 243		if (!action)
 244			goto unlock;
 245
 246		seq_printf(p, "%3d: ", i);
 247		for_each_present_cpu(cpu)
 248			seq_printf(p, "%10u ", kstat_cpu(cpu).irqs[i]);
 249		seq_printf(p, "  %s", action->name);
 250		for (action = action->next; action; action = action->next)
 251			seq_printf(p, ", %s", action->name);
 252
 253		seq_putc(p, '\n');
 254unlock:
 255		spin_unlock_irqrestore(&irq_controller_lock, flags);
 256	} else if (i == NR_IRQS) {
 257#ifdef CONFIG_ARCH_ACORN
 258		show_fiq_list(p, v);
 259#endif
 260#ifdef CONFIG_SMP
 261		show_ipi_list(p);
 262#endif
 263		seq_printf(p, "Err: %10lu\n", irq_err_count);
 264	}
 265	return 0;
 266}
 267
 268/*
 269 * IRQ lock detection.
 270 *
 271 * Hopefully, this should get us out of a few locked situations.
 272 * However, it may take a while for this to happen, since we need
 273 * a large number if IRQs to appear in the same jiffie with the
 274 * same instruction pointer (or within 2 instructions).
 275 */
 276static int check_irq_lock(struct irqdesc *desc, int irq, struct pt_regs *regs)
 277{
 278	unsigned long instr_ptr = instruction_pointer(regs);
 279
 280	if (desc->lck_jif == jiffies &&
 281	    desc->lck_pc >= instr_ptr && desc->lck_pc < instr_ptr + 8) {
 282		desc->lck_cnt += 1;
 283
 284		if (desc->lck_cnt > MAX_IRQ_CNT) {
 285			printk(KERN_ERR "IRQ LOCK: IRQ%d is locking the system, disabled\n", irq);
 286			return 1;
 287		}
 288	} else {
 289		desc->lck_cnt = 0;
 290		desc->lck_pc  = instruction_pointer(regs);
 291		desc->lck_jif = jiffies;
 292	}
 293	return 0;
 294}
 295
 296static void
 297report_bad_irq(unsigned int irq, struct pt_regs *regs, struct irqdesc *desc, int ret)
 298{
 299	static int count = 100;
 300	struct irqaction *action;
 301
 302	if (!count || noirqdebug)
 303		return;
 304
 305	count--;
 306
 307	if (ret != IRQ_HANDLED && ret != IRQ_NONE) {
 308		printk("irq%u: bogus retval mask %x\n", irq, ret);
 309	} else {
 310		printk("irq%u: nobody cared\n", irq);
 311	}
 312	show_regs(regs);
 313	dump_stack();
 314	printk(KERN_ERR "handlers:");
 315	action = desc->action;
 316	do {
 317		printk("\n" KERN_ERR "[<%p>]", action->handler);
 318		print_symbol(" (%s)", (unsigned long)action->handler);
 319		action = action->next;
 320	} while (action);
 321	printk("\n");
 322}
 323
 324static int
 325__do_irq(unsigned int irq, struct irqaction *action, struct pt_regs *regs)
 326{
 327	unsigned int status;
 328	int ret, retval = 0;
 329
 330	spin_unlock(&irq_controller_lock);
 331
 332	if (!(action->flags & SA_INTERRUPT))
 333		local_irq_enable();
 334
 335	status = 0;
 336	do {
 337		ret = action->handler(irq, action->dev_id, regs);
 338		if (ret == IRQ_HANDLED)
 339			status |= action->flags;
 340		retval |= ret;
 341		action = action->next;
 342	} while (action);
 343
 344	if (status & SA_SAMPLE_RANDOM)
 345		add_interrupt_randomness(irq);
 346
 347	spin_lock_irq(&irq_controller_lock);
 348
 349	return retval;
 350}
 351
 352/*
 353 * This is for software-decoded IRQs.  The caller is expected to
 354 * handle the ack, clear, mask and unmask issues.
 355 */
 356void
 357do_simple_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
 358{
 359	struct irqaction *action;
 360	const unsigned int cpu = smp_processor_id();
 361
 362	desc->triggered = 1;
 363
 364	kstat_cpu(cpu).irqs[irq]++;
 365
 366	smp_set_running(desc);
 367
 368	action = desc->action;
 369	if (action) {
 370		int ret = __do_irq(irq, action, regs);
 371		if (ret != IRQ_HANDLED)
 372			report_bad_irq(irq, regs, desc, ret);
 373	}
 374
 375	smp_clear_running(desc);
 376}
 377
 378/*
 379 * Most edge-triggered IRQ implementations seem to take a broken
 380 * approach to this.  Hence the complexity.
 381 */
 382void
 383do_edge_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
 384{
 385	const unsigned int cpu = smp_processor_id();
 386
 387	desc->triggered = 1;
 388
 389	/*
 390	 * If we're currently running this IRQ, or its disabled,
 391	 * we shouldn't process the IRQ.  Instead, turn on the
 392	 * hardware masks.
 393	 */
 394	if (unlikely(desc->running || desc->disable_depth))
 395		goto running;
 396
 397	/*
 398	 * Acknowledge and clear the IRQ, but don't mask it.
 399	 */
 400	desc->chip->ack(irq);
 401
 402	/*
 403	 * Mark the IRQ currently in progress.
 404	 */
 405	desc->running = 1;
 406
 407	kstat_cpu(cpu).irqs[irq]++;
 408
 409	do {
 410		struct irqaction *action;
 411
 412		action = desc->action;
 413		if (!action)
 414			break;
 415
 416		if (desc->pending && !desc->disable_depth) {
 417			desc->pending = 0;
 418			desc->chip->unmask(irq);
 419		}
 420
 421		__do_irq(irq, action, regs);
 422	} while (desc->pending && !desc->disable_depth);
 423
 424	desc->running = 0;
 425
 426	/*
 427	 * If we were disabled or freed, shut down the handler.
 428	 */
 429	if (likely(desc->action && !check_irq_lock(desc, irq, regs)))
 430		return;
 431
 432 running:
 433	/*
 434	 * We got another IRQ while this one was masked or
 435	 * currently running.  Delay it.
 436	 */
 437	desc->pending = 1;
 438	desc->chip->mask(irq);
 439	desc->chip->ack(irq);
 440}
 441
 442/*
 443 * Level-based IRQ handler.  Nice and simple.
 444 */
 445void
 446do_level_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
 447{
 448	struct irqaction *action;
 449	const unsigned int cpu = smp_processor_id();
 450
 451	desc->triggered = 1;
 452
 453	/*
 454	 * Acknowledge, clear _AND_ disable the interrupt.
 455	 */
 456	desc->chip->ack(irq);
 457
 458	if (likely(!desc->disable_depth)) {
 459		kstat_cpu(cpu).irqs[irq]++;
 460
 461		smp_set_running(desc);
 462
 463		/*
 464		 * Return with this interrupt masked if no action
 465		 */
 466		action = desc->action;
 467		if (action) {
 468			int ret = __do_irq(irq, desc->action, regs);
 469
 470			if (ret != IRQ_HANDLED)
 471				report_bad_irq(irq, regs, desc, ret);
 472
 473			if (likely(!desc->disable_depth &&
 474				   !check_irq_lock(desc, irq, regs)))
 475				desc->chip->unmask(irq);
 476		}
 477
 478		smp_clear_running(desc);
 479	}
 480}
 481
 482static void do_pending_irqs(struct pt_regs *regs)
 483{
 484	struct list_head head, *l, *n;
 485
 486	do {
 487		struct irqdesc *desc;
 488
 489		/*
 490		 * First, take the pending interrupts off the list.
 491		 * The act of calling the handlers may add some IRQs
 492		 * back onto the list.
 493		 */
 494		head = irq_pending;
 495		INIT_LIST_HEAD(&irq_pending);
 496		head.next->prev = &head;
 497		head.prev->next = &head;
 498
 499		/*
 500		 * Now run each entry.  We must delete it from our
 501		 * list before calling the handler.
 502		 */
 503		list_for_each_safe(l, n, &head) {
 504			desc = list_entry(l, struct irqdesc, pend);
 505			list_del_init(&desc->pend);
 506			desc->handle(desc - irq_desc, desc, regs);
 507		}
 508
 509		/*
 510		 * The list must be empty.
 511		 */
 512		BUG_ON(!list_empty(&head));
 513	} while (!list_empty(&irq_pending));
 514}
 515
 516/*
 517 * do_IRQ handles all hardware IRQ's.  Decoded IRQs should not
 518 * come via this function.  Instead, they should provide their
 519 * own 'handler'
 520 */
 521asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
 522{
 523	struct irqdesc *desc = irq_desc + irq;
 524
 525	/*
 526	 * Some hardware gives randomly wrong interrupts.  Rather
 527	 * than crashing, do something sensible.
 528	 */
 529	if (irq >= NR_IRQS)
 530		desc = &bad_irq_desc;
 531
 532	irq_enter();
 533	spin_lock(&irq_controller_lock);
 534	desc->handle(irq, desc, regs);
 535
 536	/*
 537	 * Now re-run any pending interrupts.
 538	 */
 539	if (!list_empty(&irq_pending))
 540		do_pending_irqs(regs);
 541
 542	irq_finish(irq);
 543
 544	spin_unlock(&irq_controller_lock);
 545	irq_exit();
 546}
 547
 548void __set_irq_handler(unsigned int irq, irq_handler_t handle, int is_chained)
 549{
 550	struct irqdesc *desc;
 551	unsigned long flags;
 552
 553	if (irq >= NR_IRQS) {
 554		printk(KERN_ERR "Trying to install handler for IRQ%d\n", irq);
 555		return;
 556	}
 557
 558	if (handle == NULL)
 559		handle = do_bad_IRQ;
 560
 561	desc = irq_desc + irq;
 562
 563	if (is_chained && desc->chip == &bad_chip)
 564		printk(KERN_WARNING "Trying to install chained handler for IRQ%d\n", irq);
 565
 566	spin_lock_irqsave(&irq_controller_lock, flags);
 567	if (handle == do_bad_IRQ) {
 568		desc->chip->mask(irq);
 569		desc->chip->ack(irq);
 570		desc->disable_depth = 1;
 571	}
 572	desc->handle = handle;
 573	if (handle != do_bad_IRQ && is_chained) {
 574		desc->valid = 0;
 575		desc->probe_ok = 0;
 576		desc->disable_depth = 0;
 577		desc->chip->unmask(irq);
 578	}
 579	spin_unlock_irqrestore(&irq_controller_lock, flags);
 580}
 581
 582void set_irq_chip(unsigned int irq, struct irqchip *chip)
 583{
 584	struct irqdesc *desc;
 585	unsigned long flags;
 586
 587	if (irq >= NR_IRQS) {
 588		printk(KERN_ERR "Trying to install chip for IRQ%d\n", irq);
 589		return;
 590	}
 591
 592	if (chip == NULL)
 593		chip = &bad_chip;
 594
 595	desc = irq_desc + irq;
 596	spin_lock_irqsave(&irq_controller_lock, flags);
 597	desc->chip = chip;
 598	spin_unlock_irqrestore(&irq_controller_lock, flags);
 599}
 600
 601int set_irq_type(unsigned int irq, unsigned int type)
 602{
 603	struct irqdesc *desc;
 604	unsigned long flags;
 605	int ret = -ENXIO;
 606
 607	if (irq >= NR_IRQS) {
 608		printk(KERN_ERR "Trying to set irq type for IRQ%d\n", irq);
 609		return -ENODEV;
 610	}
 611
 612	desc = irq_desc + irq;
 613	if (desc->chip->type) {
 614		spin_lock_irqsave(&irq_controller_lock, flags);
 615		ret = desc->chip->type(irq, type);
 616		spin_unlock_irqrestore(&irq_controller_lock, flags);
 617	}
 618
 619	return ret;
 620}
 621EXPORT_SYMBOL(set_irq_type);
 622
 623void set_irq_flags(unsigned int irq, unsigned int iflags)
 624{
 625	struct irqdesc *desc;
 626	unsigned long flags;
 627
 628	if (irq >= NR_IRQS) {
 629		printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
 630		return;
 631	}
 632
 633	desc = irq_desc + irq;
 634	spin_lock_irqsave(&irq_controller_lock, flags);
 635	desc->valid = (iflags & IRQF_VALID) != 0;
 636	desc->probe_ok = (iflags & IRQF_PROBE) != 0;
 637	desc->noautoenable = (iflags & IRQF_NOAUTOEN) != 0;
 638	spin_unlock_irqrestore(&irq_controller_lock, flags);
 639}
 640
 641int setup_irq(unsigned int irq, struct irqaction *new)
 642{
 643	int shared = 0;
 644	struct irqaction *old, **p;
 645	unsigned long flags;
 646	struct irqdesc *desc;
 647
 648	/*
 649	 * Some drivers like serial.c use request_irq() heavily,
 650	 * so we have to be careful not to interfere with a
 651	 * running system.
 652	 */
 653	if (new->flags & SA_SAMPLE_RANDOM) {
 654		/*
 655		 * This function might sleep, we want to call it first,
 656		 * outside of the atomic block.
 657		 * Yes, this might clear the entropy pool if the wrong
 658		 * driver is attempted to be loaded, without actually
 659		 * installing a new handler, but is this really a problem,
 660		 * only the sysadmin is able to do this.
 661		 */
 662	        rand_initialize_irq(irq);
 663	}
 664
 665	/*
 666	 * The following block of code has to be executed atomically
 667	 */
 668	desc = irq_desc + irq;
 669	spin_lock_irqsave(&irq_controller_lock, flags);
 670	p = &desc->action;
 671	if ((old = *p) != NULL) {
 672		/* Can't share interrupts unless both agree to */
 673		if (!(old->flags & new->flags & SA_SHIRQ)) {
 674			spin_unlock_irqrestore(&irq_controller_lock, flags);
 675			return -EBUSY;
 676		}
 677
 678		/* add new interrupt at end of irq queue */
 679		do {
 680			p = &old->next;
 681			old = *p;
 682		} while (old);
 683		shared = 1;
 684	}
 685
 686	*p = new;
 687
 688	if (!shared) {
 689 		desc->probing = 0;
 690		desc->running = 0;
 691		desc->pending = 0;
 692		desc->disable_depth = 1;
 693		if (!desc->noautoenable) {
 694			desc->disable_depth = 0;
 695			desc->chip->unmask(irq);
 696		}
 697	}
 698
 699	spin_unlock_irqrestore(&irq_controller_lock, flags);
 700	return 0;
 701}
 702
 703/**
 704 *	request_irq - allocate an interrupt line
 705 *	@irq: Interrupt line to allocate
 706 *	@handler: Function to be called when the IRQ occurs
 707 *	@irqflags: Interrupt type flags
 708 *	@devname: An ascii name for the claiming device
 709 *	@dev_id: A cookie passed back to the handler function
 710 *
 711 *	This call allocates interrupt resources and enables the
 712 *	interrupt line and IRQ handling. From the point this
 713 *	call is made your handler function may be invoked. Since
 714 *	your handler function must clear any interrupt the board
 715 *	raises, you must take care both to initialise your hardware
 716 *	and to set up the interrupt handler in the right order.
 717 *
 718 *	Dev_id must be globally unique. Normally the address of the
 719 *	device data structure is used as the cookie. Since the handler
 720 *	receives this value it makes sense to use it.
 721 *
 722 *	If your interrupt is shared you must pass a non NULL dev_id
 723 *	as this is required when freeing the interrupt.
 724 *
 725 *	Flags:
 726 *
 727 *	SA_SHIRQ		Interrupt is shared
 728 *
 729 *	SA_INTERRUPT		Disable local interrupts while processing
 730 *
 731 *	SA_SAMPLE_RANDOM	The interrupt can be used for entropy
 732 *
 733 */
 734int request_irq(unsigned int irq, irqreturn_t (*handler)(int, void *, struct pt_regs *),
 735		 unsigned long irq_flags, const char * devname, void *dev_id)
 736{
 737	unsigned long retval;
 738	struct irqaction *action;
 739
 740	if (irq >= NR_IRQS || !irq_desc[irq].valid || !handler ||
 741	    (irq_flags & SA_SHIRQ && !dev_id))
 742		return -EINVAL;
 743
 744	action = (struct irqaction *)kmalloc(sizeof(struct irqaction), GFP_KERNEL);
 745	if (!action)
 746		return -ENOMEM;
 747
 748	action->handler = handler;
 749	action->flags = irq_flags;
 750	cpus_clear(action->mask);
 751	action->name = devname;
 752	action->next = NULL;
 753	action->dev_id = dev_id;
 754
 755	retval = setup_irq(irq, action);
 756
 757	if (retval)
 758		kfree(action);
 759	return retval;
 760}
 761
 762EXPORT_SYMBOL(request_irq);
 763
 764/**
 765 *	free_irq - free an interrupt
 766 *	@irq: Interrupt line to free
 767 *	@dev_id: Device identity to free
 768 *
 769 *	Remove an interrupt handler. The handler is removed and if the
 770 *	interrupt line is no longer in use by any driver it is disabled.
 771 *	On a shared IRQ the caller must ensure the interrupt is disabled
 772 *	on the card it drives before calling this function.
 773 *
 774 *	This function must not be called from interrupt context.
 775 */
 776void free_irq(unsigned int irq, void *dev_id)
 777{
 778	struct irqaction * action, **p;
 779	unsigned long flags;
 780
 781	if (irq >= NR_IRQS || !irq_desc[irq].valid) {
 782		printk(KERN_ERR "Trying to free IRQ%d\n",irq);
 783		dump_stack();
 784		return;
 785	}
 786
 787	spin_lock_irqsave(&irq_controller_lock, flags);
 788	for (p = &irq_desc[irq].action; (action = *p) != NULL; p = &action->next) {
 789		if (action->dev_id != dev_id)
 790			continue;
 791
 792	    	/* Found it - now free it */
 793		*p = action->next;
 794		break;
 795	}
 796	spin_unlock_irqrestore(&irq_controller_lock, flags);
 797
 798	if (!action) {
 799		printk(KERN_ERR "Trying to free free IRQ%d\n",irq);
 800		dump_stack();
 801	} else {
 802		synchronize_irq(irq);
 803		kfree(action);
 804	}
 805}
 806
 807EXPORT_SYMBOL(free_irq);
 808
 809static DECLARE_MUTEX(probe_sem);
 810
 811/* Start the interrupt probing.  Unlike other architectures,
 812 * we don't return a mask of interrupts from probe_irq_on,
 813 * but return the number of interrupts enabled for the probe.
 814 * The interrupts which have been enabled for probing is
 815 * instead recorded in the irq_desc structure.
 816 */
 817unsigned long probe_irq_on(void)
 818{
 819	unsigned int i, irqs = 0;
 820	unsigned long delay;
 821
 822	down(&probe_sem);
 823
 824	/*
 825	 * first snaffle up any unassigned but
 826	 * probe-able interrupts
 827	 */
 828	spin_lock_irq(&irq_controller_lock);
 829	for (i = 0; i < NR_IRQS; i++) {
 830		if (!irq_desc[i].probe_ok || irq_desc[i].action)
 831			continue;
 832
 833		irq_desc[i].probing = 1;
 834		irq_desc[i].triggered = 0;
 835		if (irq_desc[i].chip->type)
 836			irq_desc[i].chip->type(i, IRQT_PROBE);
 837		irq_desc[i].chip->unmask(i);
 838		irqs += 1;
 839	}
 840	spin_unlock_irq(&irq_controller_lock);
 841
 842	/*
 843	 * wait for spurious interrupts to mask themselves out again
 844	 */
 845	for (delay = jiffies + HZ/10; time_before(jiffies, delay); )
 846		/* min 100ms delay */;
 847
 848	/*
 849	 * now filter out any obviously spurious interrupts
 850	 */
 851	spin_lock_irq(&irq_controller_lock);
 852	for (i = 0; i < NR_IRQS; i++) {
 853		if (irq_desc[i].probing && irq_desc[i].triggered) {
 854			irq_desc[i].probing = 0;
 855			irqs -= 1;
 856		}
 857	}
 858	spin_unlock_irq(&irq_controller_lock);
 859
 860	return irqs;
 861}
 862
 863EXPORT_SYMBOL(probe_irq_on);
 864
 865unsigned int probe_irq_mask(unsigned long irqs)
 866{
 867	unsigned int mask = 0, i;
 868
 869	spin_lock_irq(&irq_controller_lock);
 870	for (i = 0; i < 16 && i < NR_IRQS; i++)
 871		if (irq_desc[i].probing && irq_desc[i].triggered)
 872			mask |= 1 << i;
 873	spin_unlock_irq(&irq_controller_lock);
 874
 875	up(&probe_sem);
 876
 877	return mask;
 878}
 879EXPORT_SYMBOL(probe_irq_mask);
 880
 881/*
 882 * Possible return values:
 883 *  >= 0 - interrupt number
 884 *    -1 - no interrupt/many interrupts
 885 */
 886int probe_irq_off(unsigned long irqs)
 887{
 888	unsigned int i;
 889	int irq_found = NO_IRQ;
 890
 891	/*
 892	 * look at the interrupts, and find exactly one
 893	 * that we were probing has been triggered
 894	 */
 895	spin_lock_irq(&irq_controller_lock);
 896	for (i = 0; i < NR_IRQS; i++) {
 897		if (irq_desc[i].probing &&
 898		    irq_desc[i].triggered) {
 899			if (irq_found != NO_IRQ) {
 900				irq_found = NO_IRQ;
 901				goto out;
 902			}
 903			irq_found = i;
 904		}
 905	}
 906
 907	if (irq_found == -1)
 908		irq_found = NO_IRQ;
 909out:
 910	spin_unlock_irq(&irq_controller_lock);
 911
 912	up(&probe_sem);
 913
 914	return irq_found;
 915}
 916
 917EXPORT_SYMBOL(probe_irq_off);
 918
 919#ifdef CONFIG_SMP
 920static void route_irq(struct irqdesc *desc, unsigned int irq, unsigned int cpu)
 921{
 922	pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", irq, desc->cpu, cpu);
 923
 924	spin_lock_irq(&irq_controller_lock);
 925	desc->cpu = cpu;
 926	desc->chip->set_cpu(desc, irq, cpu);
 927	spin_unlock_irq(&irq_controller_lock);
 928}
 929
 930#ifdef CONFIG_PROC_FS
 931static int
 932irq_affinity_read_proc(char *page, char **start, off_t off, int count,
 933		       int *eof, void *data)
 934{
 935	struct irqdesc *desc = irq_desc + ((int)data);
 936	int len = cpumask_scnprintf(page, count, desc->affinity);
 937
 938	if (count - len < 2)
 939		return -EINVAL;
 940	page[len++] = '\n';
 941	page[len] = '\0';
 942
 943	return len;
 944}
 945
 946static int
 947irq_affinity_write_proc(struct file *file, const char __user *buffer,
 948			unsigned long count, void *data)
 949{
 950	unsigned int irq = (unsigned int)data;
 951	struct irqdesc *desc = irq_desc + irq;
 952	cpumask_t affinity, tmp;
 953	int ret = -EIO;
 954
 955	if (!desc->chip->set_cpu)
 956		goto out;
 957
 958	ret = cpumask_parse(buffer, count, affinity);
 959	if (ret)
 960		goto out;
 961
 962	cpus_and(tmp, affinity, cpu_online_map);
 963	if (cpus_empty(tmp)) {
 964		ret = -EINVAL;
 965		goto out;
 966	}
 967
 968	desc->affinity = affinity;
 969	route_irq(desc, irq, first_cpu(tmp));
 970	ret = count;
 971
 972 out:
 973	return ret;
 974}
 975#endif
 976#endif
 977
 978void __init init_irq_proc(void)
 979{
 980#if defined(CONFIG_SMP) && defined(CONFIG_PROC_FS)
 981	struct proc_dir_entry *dir;
 982	int irq;
 983
 984	dir = proc_mkdir("irq", 0);
 985	if (!dir)
 986		return;
 987
 988	for (irq = 0; irq < NR_IRQS; irq++) {
 989		struct proc_dir_entry *entry;
 990		struct irqdesc *desc;
 991		char name[16];
 992
 993		desc = irq_desc + irq;
 994		memset(name, 0, sizeof(name));
 995		snprintf(name, sizeof(name) - 1, "%u", irq);
 996
 997		desc->procdir = proc_mkdir(name, dir);
 998		if (!desc->procdir)
 999			continue;
1000
1001		entry = create_proc_entry("smp_affinity", 0600, desc->procdir);
1002		if (entry) {
1003			entry->nlink = 1;
1004			entry->data = (void *)irq;
1005			entry->read_proc = irq_affinity_read_proc;
1006			entry->write_proc = irq_affinity_write_proc;
1007		}
1008	}
1009#endif
1010}
1011
1012void __init init_IRQ(void)
1013{
1014	struct irqdesc *desc;
1015	extern void init_dma(void);
1016	int irq;
1017
1018#ifdef CONFIG_SMP
1019	bad_irq_desc.affinity = CPU_MASK_ALL;
1020	bad_irq_desc.cpu = smp_processor_id();
1021#endif
1022
1023	for (irq = 0, desc = irq_desc; irq < NR_IRQS; irq++, desc++) {
1024		*desc = bad_irq_desc;
1025		INIT_LIST_HEAD(&desc->pend);
1026	}
1027
1028	init_arch_irq();
1029	init_dma();
1030}
1031
1032static int __init noirqdebug_setup(char *str)
1033{
1034	noirqdebug = 1;
1035	return 1;
1036}
1037
1038__setup("noirqdebug", noirqdebug_setup);