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