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  *  Support for Dynamic Tick Timer Copyright (C) 2004-2005 Nokia Corporation.
   8  *  Dynamic Tick Timer written by Tony Lindgren <tony@atomide.com> and
   9  *  Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>.
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  *
  15  *  This file contains the code used by various IRQ handling routines:
  16  *  asking for different IRQ's should be done through these routines
  17  *  instead of just grabbing them. Thus setups with different IRQ numbers
  18  *  shouldn't result in any weird surprises, and installing new handlers
  19  *  should be easier.
  20  *
  21  *  IRQ's are in fact implemented a bit like signal handlers for the kernel.
  22  *  Naturally it's not a 1:1 relation, but there are similarities.
  23  */
  24 #include <linux/config.h>
  25 #include <linux/kernel_stat.h>
  26 #include <linux/module.h>
  27 #include <linux/signal.h>
  28 #include <linux/ioport.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/ptrace.h>
  31 #include <linux/slab.h>
  32 #include <linux/random.h>
  33 #include <linux/smp.h>
  34 #include <linux/init.h>
  35 #include <linux/seq_file.h>
  36 #include <linux/errno.h>
  37 #include <linux/list.h>
  38 #include <linux/kallsyms.h>
  39 #include <linux/proc_fs.h>
  40
  41 #include <asm/irq.h>
  42 #include <asm/system.h>
  43 #include <asm/mach/irq.h>
  44 #include <asm/mach/time.h>
  45
  46 /*
  47  * Maximum IRQ count.  Currently, this is arbitary.  However, it should
  48  * not be set too low to prevent false triggering.  Conversely, if it
  49  * is set too high, then you could miss a stuck IRQ.
  50  *
  51  * Maybe we ought to set a timer and re-enable the IRQ at a later time?
  52  */
  53 #define MAX_IRQ_CNT     100000
  54
  55 static int noirqdebug;
  56 static volatile unsigned long irq_err_count;
  57 static DEFINE_SPINLOCK(irq_controller_lock);
  58 static LIST_HEAD(irq_pending);
  59
  60 struct irqdesc irq_desc[NR_IRQS];
  61 void (*init_arch_irq)(void) __initdata = NULL;
  62
  63 /*
  64  * No architecture-specific irq_finish function defined in arm/arch/irqs.h.
  65  */
  66 #ifndef irq_finish
  67 #define irq_finish(irq) do { } while (0)
  68 #endif
  69
  70 /*
  71  * Dummy mask/unmask handler
  72  */
  73 void dummy_mask_unmask_irq(unsigned int irq)
  74 {
  75 }
  76
  77 irqreturn_t no_action(int irq, void *dev_id, struct pt_regs *regs)
  78 {
  79         return IRQ_NONE;
  80 }
  81
  82 void do_bad_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
  83 {
  84         irq_err_count += 1;
  85         printk(KERN_ERR "IRQ: spurious interrupt %d\n", irq);
  86 }
  87
  88 static struct irqchip bad_chip = {
  89         .ack    = dummy_mask_unmask_irq,
  90         .mask   = dummy_mask_unmask_irq,
  91         .unmask = dummy_mask_unmask_irq,
  92 };
  93
  94 static struct irqdesc bad_irq_desc = {
  95         .chip           = &bad_chip,
  96         .handle         = do_bad_IRQ,
  97         .pend           = LIST_HEAD_INIT(bad_irq_desc.pend),
  98         .disable_depth  = 1,
  99 };
 100
 101 #ifdef CONFIG_SMP
 102 void synchronize_irq(unsigned int irq)
 103 {
 104         struct irqdesc *desc = irq_desc + irq;
 105
 106         while (desc->running)
 107                 barrier();
 108 }
 109 EXPORT_SYMBOL(synchronize_irq);
 110
 111 #define smp_set_running(desc)   do { desc->running = 1; } while (0)
 112 #define smp_clear_running(desc) do { desc->running = 0; } while (0)
 113 #else
 114 #define smp_set_running(desc)   do { } while (0)
 115 #define smp_clear_running(desc) do { } while (0)
 116 #endif
 117
 118 /**
 119  *      disable_irq_nosync - disable an irq without waiting
 120  *      @irq: Interrupt to disable
 121  *
 122  *      Disable the selected interrupt line.  Enables and disables
 123  *      are nested.  We do this lazily.
 124  *
 125  *      This function may be called from IRQ context.
 126  */
 127 void disable_irq_nosync(unsigned int irq)
 128 {
 129         struct irqdesc *desc = irq_desc + irq;
 130         unsigned long flags;
 131
 132         spin_lock_irqsave(&irq_controller_lock, flags);
 133         desc->disable_depth++;
 134         list_del_init(&desc->pend);
 135         spin_unlock_irqrestore(&irq_controller_lock, flags);
 136 }
 137 EXPORT_SYMBOL(disable_irq_nosync);
 138
 139 /**
 140  *      disable_irq - disable an irq and wait for completion
 141  *      @irq: Interrupt to disable
 142  *
 143  *      Disable the selected interrupt line.  Enables and disables
 144  *      are nested.  This functions waits for any pending IRQ
 145  *      handlers for this interrupt to complete before returning.
 146  *      If you use this function while holding a resource the IRQ
 147  *      handler may need you will deadlock.
 148  *
 149  *      This function may be called - with care - from IRQ context.
 150  */
 151 void disable_irq(unsigned int irq)
 152 {
 153         struct irqdesc *desc = irq_desc + irq;
 154
 155         disable_irq_nosync(irq);
 156         if (desc->action)
 157                 synchronize_irq(irq);
 158 }
 159 EXPORT_SYMBOL(disable_irq);
 160
 161 /**
 162  *      enable_irq - enable interrupt handling on an irq
 163  *      @irq: Interrupt to enable
 164  *
 165  *      Re-enables the processing of interrupts on this IRQ line.
 166  *      Note that this may call the interrupt handler, so you may
 167  *      get unexpected results if you hold IRQs disabled.
 168  *
 169  *      This function may be called from IRQ context.
 170  */
 171 void enable_irq(unsigned int irq)
 172 {
 173         struct irqdesc *desc = irq_desc + irq;
 174         unsigned long flags;
 175
 176         spin_lock_irqsave(&irq_controller_lock, flags);
 177         if (unlikely(!desc->disable_depth)) {
 178                 printk("enable_irq(%u) unbalanced from %p\n", irq,
 179                         __builtin_return_address(0));
 180         } else if (!--desc->disable_depth) {
 181                 desc->probing = 0;
 182                 desc->chip->unmask(irq);
 183
 184                 /*
 185                  * If the interrupt is waiting to be processed,
 186                  * try to re-run it.  We can't directly run it
 187                  * from here since the caller might be in an
 188                  * interrupt-protected region.
 189                  */
 190                 if (desc->pending && list_empty(&desc->pend)) {
 191                         desc->pending = 0;
 192                         if (!desc->chip->retrigger ||
 193                             desc->chip->retrigger(irq))
 194                                 list_add(&desc->pend, &irq_pending);
 195                 }
 196         }
 197         spin_unlock_irqrestore(&irq_controller_lock, flags);
 198 }
 199 EXPORT_SYMBOL(enable_irq);
 200
 201 /*
 202  * Enable wake on selected irq
 203  */
 204 void enable_irq_wake(unsigned int irq)
 205 {
 206         struct irqdesc *desc = irq_desc + irq;
 207         unsigned long flags;
 208
 209         spin_lock_irqsave(&irq_controller_lock, flags);
 210         if (desc->chip->set_wake)
 211                 desc->chip->set_wake(irq, 1);
 212         spin_unlock_irqrestore(&irq_controller_lock, flags);
 213 }
 214 EXPORT_SYMBOL(enable_irq_wake);
 215
 216 void disable_irq_wake(unsigned int irq)
 217 {
 218         struct irqdesc *desc = irq_desc + irq;
 219         unsigned long flags;
 220
 221         spin_lock_irqsave(&irq_controller_lock, flags);
 222         if (desc->chip->set_wake)
 223                 desc->chip->set_wake(irq, 0);
 224         spin_unlock_irqrestore(&irq_controller_lock, flags);
 225 }
 226 EXPORT_SYMBOL(disable_irq_wake);
 227
 228 int show_interrupts(struct seq_file *p, void *v)
 229 {
 230         int i = *(loff_t *) v, cpu;
 231         struct irqaction * action;
 232         unsigned long flags;
 233
 234         if (i == 0) {
 235                 char cpuname[12];
 236
 237                 seq_printf(p, "    ");
 238                 for_each_present_cpu(cpu) {
 239                         sprintf(cpuname, "CPU%d", cpu);
 240                         seq_printf(p, " %10s", cpuname);
 241                 }
 242                 seq_putc(p, '\n');
 243         }
 244
 245         if (i < NR_IRQS) {
 246                 spin_lock_irqsave(&irq_controller_lock, flags);
 247                 action = irq_desc[i].action;
 248                 if (!action)
 249                         goto unlock;
 250
 251                 seq_printf(p, "%3d: ", i);
 252                 for_each_present_cpu(cpu)
 253                         seq_printf(p, "%10u ", kstat_cpu(cpu).irqs[i]);
 254                 seq_printf(p, "  %s", action->name);
 255                 for (action = action->next; action; action = action->next)
 256                         seq_printf(p, ", %s", action->name);
 257
 258                 seq_putc(p, '\n');
 259 unlock:
 260                 spin_unlock_irqrestore(&irq_controller_lock, flags);
 261         } else if (i == NR_IRQS) {
 262 #ifdef CONFIG_ARCH_ACORN
 263                 show_fiq_list(p, v);
 264 #endif
 265 #ifdef CONFIG_SMP
 266                 show_ipi_list(p);
 267                 show_local_irqs(p);
 268 #endif
 269                 seq_printf(p, "Err: %10lu\n", irq_err_count);
 270         }
 271         return 0;
 272 }
 273
 274 /*
 275  * IRQ lock detection.
 276  *
 277  * Hopefully, this should get us out of a few locked situations.
 278  * However, it may take a while for this to happen, since we need
 279  * a large number if IRQs to appear in the same jiffie with the
 280  * same instruction pointer (or within 2 instructions).
 281  */
 282 static int check_irq_lock(struct irqdesc *desc, int irq, struct pt_regs *regs)
 283 {
 284         unsigned long instr_ptr = instruction_pointer(regs);
 285
 286         if (desc->lck_jif == jiffies &&
 287             desc->lck_pc >= instr_ptr && desc->lck_pc < instr_ptr + 8) {
 288                 desc->lck_cnt += 1;
 289
 290                 if (desc->lck_cnt > MAX_IRQ_CNT) {
 291                         printk(KERN_ERR "IRQ LOCK: IRQ%d is locking the system, disabled\n", irq);
 292                         return 1;
 293                 }
 294         } else {
 295                 desc->lck_cnt = 0;
 296                 desc->lck_pc  = instruction_pointer(regs);
 297                 desc->lck_jif = jiffies;
 298         }
 299         return 0;
 300 }
 301
 302 static void
 303 report_bad_irq(unsigned int irq, struct pt_regs *regs, struct irqdesc *desc, int ret)
 304 {
 305         static int count = 100;
 306         struct irqaction *action;
 307
 308         if (noirqdebug)
 309                 return;
 310
 311         if (ret != IRQ_HANDLED && ret != IRQ_NONE) {
 312                 if (!count)
 313                         return;
 314                 count--;
 315                 printk("irq%u: bogus retval mask %x\n", irq, ret);
 316         } else {
 317                 desc->irqs_unhandled++;
 318                 if (desc->irqs_unhandled <= 99900)
 319                         return;
 320                 desc->irqs_unhandled = 0;
 321                 printk("irq%u: nobody cared\n", irq);
 322         }
 323         show_regs(regs);
 324         dump_stack();
 325         printk(KERN_ERR "handlers:");
 326         action = desc->action;
 327         do {
 328                 printk("\n" KERN_ERR "[<%p>]", action->handler);
 329                 print_symbol(" (%s)", (unsigned long)action->handler);
 330                 action = action->next;
 331         } while (action);
 332         printk("\n");
 333 }
 334
 335 static int
 336 __do_irq(unsigned int irq, struct irqaction *action, struct pt_regs *regs)
 337 {
 338         unsigned int status;
 339         int ret, retval = 0;
 340
 341         spin_unlock(&irq_controller_lock);
 342
 343 #ifdef CONFIG_NO_IDLE_HZ
 344         if (!(action->flags & SA_TIMER) && system_timer->dyn_tick != NULL) {
 345                 write_seqlock(&xtime_lock);
 346                 if (system_timer->dyn_tick->state & DYN_TICK_ENABLED)
 347                         system_timer->dyn_tick->handler(irq, 0, regs);
 348                 write_sequnlock(&xtime_lock);
 349         }
 350 #endif
 351
 352         if (!(action->flags & SA_INTERRUPT))
 353                 local_irq_enable();
 354
 355         status = 0;
 356         do {
 357                 ret = action->handler(irq, action->dev_id, regs);
 358                 if (ret == IRQ_HANDLED)
 359                         status |= action->flags;
 360                 retval |= ret;
 361                 action = action->next;
 362         } while (action);
 363
 364         if (status & SA_SAMPLE_RANDOM)
 365                 add_interrupt_randomness(irq);
 366
 367         spin_lock_irq(&irq_controller_lock);
 368
 369         return retval;
 370 }
 371
 372 /*
 373  * This is for software-decoded IRQs.  The caller is expected to
 374  * handle the ack, clear, mask and unmask issues.
 375  */
 376 void
 377 do_simple_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
 378 {
 379         struct irqaction *action;
 380         const unsigned int cpu = smp_processor_id();
 381
 382         desc->triggered = 1;
 383
 384         kstat_cpu(cpu).irqs[irq]++;
 385
 386         smp_set_running(desc);
 387
 388         action = desc->action;
 389         if (action) {
 390                 int ret = __do_irq(irq, action, regs);
 391                 if (ret != IRQ_HANDLED)
 392                         report_bad_irq(irq, regs, desc, ret);
 393         }
 394
 395         smp_clear_running(desc);
 396 }
 397
 398 /*
 399  * Most edge-triggered IRQ implementations seem to take a broken
 400  * approach to this.  Hence the complexity.
 401  */
 402 void
 403 do_edge_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
 404 {
 405         const unsigned int cpu = smp_processor_id();
 406
 407         desc->triggered = 1;
 408
 409         /*
 410          * If we're currently running this IRQ, or its disabled,
 411          * we shouldn't process the IRQ.  Instead, turn on the
 412          * hardware masks.
 413          */
 414         if (unlikely(desc->running || desc->disable_depth))
 415                 goto running;
 416
 417         /*
 418          * Acknowledge and clear the IRQ, but don't mask it.
 419          */
 420         desc->chip->ack(irq);
 421
 422         /*
 423          * Mark the IRQ currently in progress.
 424          */
 425         desc->running = 1;
 426
 427         kstat_cpu(cpu).irqs[irq]++;
 428
 429         do {
 430                 struct irqaction *action;
 431
 432                 action = desc->action;
 433                 if (!action)
 434                         break;
 435
 436                 if (desc->pending && !desc->disable_depth) {
 437                         desc->pending = 0;
 438                         desc->chip->unmask(irq);
 439                 }
 440
 441                 __do_irq(irq, action, regs);
 442         } while (desc->pending && !desc->disable_depth);
 443
 444         desc->running = 0;
 445
 446         /*
 447          * If we were disabled or freed, shut down the handler.
 448          */
 449         if (likely(desc->action && !check_irq_lock(desc, irq, regs)))
 450                 return;
 451
 452  running:
 453         /*
 454          * We got another IRQ while this one was masked or
 455          * currently running.  Delay it.
 456          */
 457         desc->pending = 1;
 458         desc->chip->mask(irq);
 459         desc->chip->ack(irq);
 460 }
 461
 462 /*
 463  * Level-based IRQ handler.  Nice and simple.
 464  */
 465 void
 466 do_level_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
 467 {
 468         struct irqaction *action;
 469         const unsigned int cpu = smp_processor_id();
 470
 471         desc->triggered = 1;
 472
 473         /*
 474          * Acknowledge, clear _AND_ disable the interrupt.
 475          */
 476         desc->chip->ack(irq);
 477
 478         if (likely(!desc->disable_depth)) {
 479                 kstat_cpu(cpu).irqs[irq]++;
 480
 481                 smp_set_running(desc);
 482
 483                 /*
 484                  * Return with this interrupt masked if no action
 485                  */
 486                 action = desc->action;
 487                 if (action) {
 488                         int ret = __do_irq(irq, desc->action, regs);
 489
 490                         if (ret != IRQ_HANDLED)
 491                                 report_bad_irq(irq, regs, desc, ret);
 492
 493                         if (likely(!desc->disable_depth &&
 494                                    !check_irq_lock(desc, irq, regs)))
 495                                 desc->chip->unmask(irq);
 496                 }
 497
 498                 smp_clear_running(desc);
 499         }
 500 }
 501
 502 static void do_pending_irqs(struct pt_regs *regs)
 503 {
 504         struct list_head head, *l, *n;
 505
 506         do {
 507                 struct irqdesc *desc;
 508
 509                 /*
 510                  * First, take the pending interrupts off the list.
 511                  * The act of calling the handlers may add some IRQs
 512                  * back onto the list.
 513                  */
 514                 head = irq_pending;
 515                 INIT_LIST_HEAD(&irq_pending);
 516                 head.next->prev = &head;
 517                 head.prev->next = &head;
 518
 519                 /*
 520                  * Now run each entry.  We must delete it from our
 521                  * list before calling the handler.
 522                  */
 523                 list_for_each_safe(l, n, &head) {
 524                         desc = list_entry(l, struct irqdesc, pend);
 525                         list_del_init(&desc->pend);
 526                         desc_handle_irq(desc - irq_desc, desc, regs);
 527                 }
 528
 529                 /*
 530                  * The list must be empty.
 531                  */
 532                 BUG_ON(!list_empty(&head));
 533         } while (!list_empty(&irq_pending));
 534 }
 535
 536 /*
 537  * do_IRQ handles all hardware IRQ's.  Decoded IRQs should not
 538  * come via this function.  Instead, they should provide their
 539  * own 'handler'
 540  */
 541 asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
 542 {
 543         struct irqdesc *desc = irq_desc + irq;
 544
 545         /*
 546          * Some hardware gives randomly wrong interrupts.  Rather
 547          * than crashing, do something sensible.
 548          */
 549         if (irq >= NR_IRQS)
 550                 desc = &bad_irq_desc;
 551
 552         irq_enter();
 553         spin_lock(&irq_controller_lock);
 554         desc_handle_irq(irq, desc, regs);
 555
 556         /*
 557          * Now re-run any pending interrupts.
 558          */
 559         if (!list_empty(&irq_pending))
 560                 do_pending_irqs(regs);
 561
 562         irq_finish(irq);
 563
 564         spin_unlock(&irq_controller_lock);
 565         irq_exit();
 566 }
 567
 568 void __set_irq_handler(unsigned int irq, irq_handler_t handle, int is_chained)
 569 {
 570         struct irqdesc *desc;
 571         unsigned long flags;
 572
 573         if (irq >= NR_IRQS) {
 574                 printk(KERN_ERR "Trying to install handler for IRQ%d\n", irq);
 575                 return;
 576         }
 577
 578         if (handle == NULL)
 579                 handle = do_bad_IRQ;
 580
 581         desc = irq_desc + irq;
 582
 583         if (is_chained && desc->chip == &bad_chip)
 584                 printk(KERN_WARNING "Trying to install chained handler for IRQ%d\n", irq);
 585
 586         spin_lock_irqsave(&irq_controller_lock, flags);
 587         if (handle == do_bad_IRQ) {
 588                 desc->chip->mask(irq);
 589                 desc->chip->ack(irq);
 590                 desc->disable_depth = 1;
 591         }
 592         desc->handle = handle;
 593         if (handle != do_bad_IRQ && is_chained) {
 594                 desc->valid = 0;
 595                 desc->probe_ok = 0;
 596                 desc->disable_depth = 0;
 597                 desc->chip->unmask(irq);
 598         }
 599         spin_unlock_irqrestore(&irq_controller_lock, flags);
 600 }
 601
 602 void set_irq_chip(unsigned int irq, struct irqchip *chip)
 603 {
 604         struct irqdesc *desc;
 605         unsigned long flags;
 606
 607         if (irq >= NR_IRQS) {
 608                 printk(KERN_ERR "Trying to install chip for IRQ%d\n", irq);
 609                 return;
 610         }
 611
 612         if (chip == NULL)
 613                 chip = &bad_chip;
 614
 615         desc = irq_desc + irq;
 616         spin_lock_irqsave(&irq_controller_lock, flags);
 617         desc->chip = chip;
 618         spin_unlock_irqrestore(&irq_controller_lock, flags);
 619 }
 620
 621 int set_irq_type(unsigned int irq, unsigned int type)
 622 {
 623         struct irqdesc *desc;
 624         unsigned long flags;
 625         int ret = -ENXIO;
 626
 627         if (irq >= NR_IRQS) {
 628                 printk(KERN_ERR "Trying to set irq type for IRQ%d\n", irq);
 629                 return -ENODEV;
 630         }
 631
 632         desc = irq_desc + irq;
 633         if (desc->chip->set_type) {
 634                 spin_lock_irqsave(&irq_controller_lock, flags);
 635                 ret = desc->chip->set_type(irq, type);
 636                 spin_unlock_irqrestore(&irq_controller_lock, flags);
 637         }
 638
 639         return ret;
 640 }
 641 EXPORT_SYMBOL(set_irq_type);
 642
 643 void set_irq_flags(unsigned int irq, unsigned int iflags)
 644 {
 645         struct irqdesc *desc;
 646         unsigned long flags;
 647
 648         if (irq >= NR_IRQS) {
 649                 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
 650                 return;
 651         }
 652
 653         desc = irq_desc + irq;
 654         spin_lock_irqsave(&irq_controller_lock, flags);
 655         desc->valid = (iflags & IRQF_VALID) != 0;
 656         desc->probe_ok = (iflags & IRQF_PROBE) != 0;
 657         desc->noautoenable = (iflags & IRQF_NOAUTOEN) != 0;
 658         spin_unlock_irqrestore(&irq_controller_lock, flags);
 659 }
 660
 661 int setup_irq(unsigned int irq, struct irqaction *new)
 662 {
 663         int shared = 0;
 664         struct irqaction *old, **p;
 665         unsigned long flags;
 666         struct irqdesc *desc;
 667
 668         /*
 669          * Some drivers like serial.c use request_irq() heavily,
 670          * so we have to be careful not to interfere with a
 671          * running system.
 672          */
 673         if (new->flags & SA_SAMPLE_RANDOM) {
 674                 /*
 675                  * This function might sleep, we want to call it first,
 676                  * outside of the atomic block.
 677                  * Yes, this might clear the entropy pool if the wrong
 678                  * driver is attempted to be loaded, without actually
 679                  * installing a new handler, but is this really a problem,
 680                  * only the sysadmin is able to do this.
 681                  */
 682                 rand_initialize_irq(irq);
 683         }
 684
 685         /*
 686          * The following block of code has to be executed atomically
 687          */
 688         desc = irq_desc + irq;
 689         spin_lock_irqsave(&irq_controller_lock, flags);
 690         p = &desc->action;
 691         if ((old = *p) != NULL) {
 692                 /*
 693                  * Can't share interrupts unless both agree to and are
 694                  * the same type.
 695                  */
 696                 if (!(old->flags & new->flags & SA_SHIRQ) ||
 697                     (~old->flags & new->flags) & SA_TRIGGER_MASK) {
 698                         spin_unlock_irqrestore(&irq_controller_lock, flags);
 699                         return -EBUSY;
 700                 }
 701
 702                 /* add new interrupt at end of irq queue */
 703                 do {
 704                         p = &old->next;
 705                         old = *p;
 706                 } while (old);
 707                 shared = 1;
 708         }
 709
 710         *p = new;
 711
 712         if (!shared) {
 713                 desc->probing = 0;
 714                 desc->running = 0;
 715                 desc->pending = 0;
 716                 desc->disable_depth = 1;
 717
 718                 if (new->flags & SA_TRIGGER_MASK &&
 719                     desc->chip->set_type) {
 720                         unsigned int type = new->flags & SA_TRIGGER_MASK;
 721                         desc->chip->set_type(irq, type);
 722                 }
 723
 724                 if (!desc->noautoenable) {
 725                         desc->disable_depth = 0;
 726                         desc->chip->unmask(irq);
 727                 }
 728         }
 729
 730         spin_unlock_irqrestore(&irq_controller_lock, flags);
 731         return 0;
 732 }
 733
 734 /**
 735  *      request_irq - allocate an interrupt line
 736  *      @irq: Interrupt line to allocate
 737  *      @handler: Function to be called when the IRQ occurs
 738  *      @irqflags: Interrupt type flags
 739  *      @devname: An ascii name for the claiming device
 740  *      @dev_id: A cookie passed back to the handler function
 741  *
 742  *      This call allocates interrupt resources and enables the
 743  *      interrupt line and IRQ handling. From the point this
 744  *      call is made your handler function may be invoked. Since
 745  *      your handler function must clear any interrupt the board
 746  *      raises, you must take care both to initialise your hardware
 747  *      and to set up the interrupt handler in the right order.
 748  *
 749  *      Dev_id must be globally unique. Normally the address of the
 750  *      device data structure is used as the cookie. Since the handler
 751  *      receives this value it makes sense to use it.
 752  *
 753  *      If your interrupt is shared you must pass a non NULL dev_id
 754  *      as this is required when freeing the interrupt.
 755  *
 756  *      Flags:
 757  *
 758  *      SA_SHIRQ                Interrupt is shared
 759  *
 760  *      SA_INTERRUPT            Disable local interrupts while processing
 761  *
 762  *      SA_SAMPLE_RANDOM        The interrupt can be used for entropy
 763  *
 764  */
 765 int request_irq(unsigned int irq, irqreturn_t (*handler)(int, void *, struct pt_regs *),
 766                  unsigned long irq_flags, const char * devname, void *dev_id)
 767 {
 768         unsigned long retval;
 769         struct irqaction *action;
 770
 771         if (irq >= NR_IRQS || !irq_desc[irq].valid || !handler ||
 772             (irq_flags & SA_SHIRQ && !dev_id))
 773                 return -EINVAL;
 774
 775         action = (struct irqaction *)kmalloc(sizeof(struct irqaction), GFP_KERNEL);
 776         if (!action)
 777                 return -ENOMEM;
 778
 779         action->handler = handler;
 780         action->flags = irq_flags;
 781         cpus_clear(action->mask);
 782         action->name = devname;
 783         action->next = NULL;
 784         action->dev_id = dev_id;
 785
 786         retval = setup_irq(irq, action);
 787
 788         if (retval)
 789                 kfree(action);
 790         return retval;
 791 }
 792
 793 EXPORT_SYMBOL(request_irq);
 794
 795 /**
 796  *      free_irq - free an interrupt
 797  *      @irq: Interrupt line to free
 798  *      @dev_id: Device identity to free
 799  *
 800  *      Remove an interrupt handler. The handler is removed and if the
 801  *      interrupt line is no longer in use by any driver it is disabled.
 802  *      On a shared IRQ the caller must ensure the interrupt is disabled
 803  *      on the card it drives before calling this function.
 804  *
 805  *      This function must not be called from interrupt context.
 806  */
 807 void free_irq(unsigned int irq, void *dev_id)
 808 {
 809         struct irqaction * action, **p;
 810         unsigned long flags;
 811
 812         if (irq >= NR_IRQS || !irq_desc[irq].valid) {
 813                 printk(KERN_ERR "Trying to free IRQ%d\n",irq);
 814                 dump_stack();
 815                 return;
 816         }
 817
 818         spin_lock_irqsave(&irq_controller_lock, flags);
 819         for (p = &irq_desc[irq].action; (action = *p) != NULL; p = &action->next) {
 820                 if (action->dev_id != dev_id)
 821                         continue;
 822
 823                 /* Found it - now free it */
 824                 *p = action->next;
 825                 break;
 826         }
 827         spin_unlock_irqrestore(&irq_controller_lock, flags);
 828
 829         if (!action) {
 830                 printk(KERN_ERR "Trying to free free IRQ%d\n",irq);
 831                 dump_stack();
 832         } else {
 833                 synchronize_irq(irq);
 834                 kfree(action);
 835         }
 836 }
 837
 838 EXPORT_SYMBOL(free_irq);
 839
 840 static DECLARE_MUTEX(probe_sem);
 841
 842 /* Start the interrupt probing.  Unlike other architectures,
 843  * we don't return a mask of interrupts from probe_irq_on,
 844  * but return the number of interrupts enabled for the probe.
 845  * The interrupts which have been enabled for probing is
 846  * instead recorded in the irq_desc structure.
 847  */
 848 unsigned long probe_irq_on(void)
 849 {
 850         unsigned int i, irqs = 0;
 851         unsigned long delay;
 852
 853         down(&probe_sem);
 854
 855         /*
 856          * first snaffle up any unassigned but
 857          * probe-able interrupts
 858          */
 859         spin_lock_irq(&irq_controller_lock);
 860         for (i = 0; i < NR_IRQS; i++) {
 861                 if (!irq_desc[i].probe_ok || irq_desc[i].action)
 862                         continue;
 863
 864                 irq_desc[i].probing = 1;
 865                 irq_desc[i].triggered = 0;
 866                 if (irq_desc[i].chip->set_type)
 867                         irq_desc[i].chip->set_type(i, IRQT_PROBE);
 868                 irq_desc[i].chip->unmask(i);
 869                 irqs += 1;
 870         }
 871         spin_unlock_irq(&irq_controller_lock);
 872
 873         /*
 874          * wait for spurious interrupts to mask themselves out again
 875          */
 876         for (delay = jiffies + HZ/10; time_before(jiffies, delay); )
 877                 /* min 100ms delay */;
 878
 879         /*
 880          * now filter out any obviously spurious interrupts
 881          */
 882         spin_lock_irq(&irq_controller_lock);
 883         for (i = 0; i < NR_IRQS; i++) {
 884                 if (irq_desc[i].probing && irq_desc[i].triggered) {
 885                         irq_desc[i].probing = 0;
 886                         irqs -= 1;
 887                 }
 888         }
 889         spin_unlock_irq(&irq_controller_lock);
 890
 891         return irqs;
 892 }
 893
 894 EXPORT_SYMBOL(probe_irq_on);
 895
 896 unsigned int probe_irq_mask(unsigned long irqs)
 897 {
 898         unsigned int mask = 0, i;
 899
 900         spin_lock_irq(&irq_controller_lock);
 901         for (i = 0; i < 16 && i < NR_IRQS; i++)
 902                 if (irq_desc[i].probing && irq_desc[i].triggered)
 903                         mask |= 1 << i;
 904         spin_unlock_irq(&irq_controller_lock);
 905
 906         up(&probe_sem);
 907
 908         return mask;
 909 }
 910 EXPORT_SYMBOL(probe_irq_mask);
 911
 912 /*
 913  * Possible return values:
 914  *  >= 0 - interrupt number
 915  *    -1 - no interrupt/many interrupts
 916  */
 917 int probe_irq_off(unsigned long irqs)
 918 {
 919         unsigned int i;
 920         int irq_found = NO_IRQ;
 921
 922         /*
 923          * look at the interrupts, and find exactly one
 924          * that we were probing has been triggered
 925          */
 926         spin_lock_irq(&irq_controller_lock);
 927         for (i = 0; i < NR_IRQS; i++) {
 928                 if (irq_desc[i].probing &&
 929                     irq_desc[i].triggered) {
 930                         if (irq_found != NO_IRQ) {
 931                                 irq_found = NO_IRQ;
 932                                 goto out;
 933                         }
 934                         irq_found = i;
 935                 }
 936         }
 937
 938         if (irq_found == -1)
 939                 irq_found = NO_IRQ;
 940 out:
 941         spin_unlock_irq(&irq_controller_lock);
 942
 943         up(&probe_sem);
 944
 945         return irq_found;
 946 }
 947
 948 EXPORT_SYMBOL(probe_irq_off);
 949
 950 #ifdef CONFIG_SMP
 951 static void route_irq(struct irqdesc *desc, unsigned int irq, unsigned int cpu)
 952 {
 953         pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", irq, desc->cpu, cpu);
 954
 955         spin_lock_irq(&irq_controller_lock);
 956         desc->cpu = cpu;
 957         desc->chip->set_cpu(desc, irq, cpu);
 958         spin_unlock_irq(&irq_controller_lock);
 959 }
 960
 961 #ifdef CONFIG_PROC_FS
 962 static int
 963 irq_affinity_read_proc(char *page, char **start, off_t off, int count,
 964                        int *eof, void *data)
 965 {
 966         struct irqdesc *desc = irq_desc + ((int)data);
 967         int len = cpumask_scnprintf(page, count, desc->affinity);
 968
 969         if (count - len < 2)
 970                 return -EINVAL;
 971         page[len++] = '\n';
 972         page[len] = '\0';
 973
 974         return len;
 975 }
 976
 977 static int
 978 irq_affinity_write_proc(struct file *file, const char __user *buffer,
 979                         unsigned long count, void *data)
 980 {
 981         unsigned int irq = (unsigned int)data;
 982         struct irqdesc *desc = irq_desc + irq;
 983         cpumask_t affinity, tmp;
 984         int ret = -EIO;
 985
 986         if (!desc->chip->set_cpu)
 987                 goto out;
 988
 989         ret = cpumask_parse(buffer, count, affinity);
 990         if (ret)
 991                 goto out;
 992
 993         cpus_and(tmp, affinity, cpu_online_map);
 994         if (cpus_empty(tmp)) {
 995                 ret = -EINVAL;
 996                 goto out;
 997         }
 998
 999         desc->affinity = affinity;
1000         route_irq(desc, irq, first_cpu(tmp));
1001         ret = count;
1002
1003  out:
1004         return ret;
1005 }
1006 #endif
1007 #endif
1008
1009 void __init init_irq_proc(void)
1010 {
1011 #if defined(CONFIG_SMP) && defined(CONFIG_PROC_FS)
1012         struct proc_dir_entry *dir;
1013         int irq;
1014
1015         dir = proc_mkdir("irq", NULL);
1016         if (!dir)
1017                 return;
1018
1019         for (irq = 0; irq < NR_IRQS; irq++) {
1020                 struct proc_dir_entry *entry;
1021                 struct irqdesc *desc;
1022                 char name[16];
1023
1024                 desc = irq_desc + irq;
1025                 memset(name, 0, sizeof(name));
1026                 snprintf(name, sizeof(name) - 1, "%u", irq);
1027
1028                 desc->procdir = proc_mkdir(name, dir);
1029                 if (!desc->procdir)
1030                         continue;
1031
1032                 entry = create_proc_entry("smp_affinity", 0600, desc->procdir);
1033                 if (entry) {
1034                         entry->nlink = 1;
1035                         entry->data = (void *)irq;
1036                         entry->read_proc = irq_affinity_read_proc;
1037                         entry->write_proc = irq_affinity_write_proc;
1038                 }
1039         }
1040 #endif
1041 }
1042
1043 void __init init_IRQ(void)
1044 {
1045         struct irqdesc *desc;
1046         int irq;
1047
1048 #ifdef CONFIG_SMP
1049         bad_irq_desc.affinity = CPU_MASK_ALL;
1050         bad_irq_desc.cpu = smp_processor_id();
1051 #endif
1052
1053         for (irq = 0, desc = irq_desc; irq < NR_IRQS; irq++, desc++) {
1054                 *desc = bad_irq_desc;
1055                 INIT_LIST_HEAD(&desc->pend);
1056         }
1057
1058         init_arch_irq();
1059 }
1060
1061 static int __init noirqdebug_setup(char *str)
1062 {
1063         noirqdebug = 1;
1064         return 1;
1065 }
1066
1067 __setup("noirqdebug", noirqdebug_setup);
1068
1069 #ifdef CONFIG_HOTPLUG_CPU
1070 /*
1071  * The CPU has been marked offline.  Migrate IRQs off this CPU.  If
1072  * the affinity settings do not allow other CPUs, force them onto any
1073  * available CPU.
1074  */
1075 void migrate_irqs(void)
1076 {
1077         unsigned int i, cpu = smp_processor_id();
1078
1079         for (i = 0; i < NR_IRQS; i++) {
1080                 struct irqdesc *desc = irq_desc + i;
1081
1082                 if (desc->cpu == cpu) {
1083                         unsigned int newcpu = any_online_cpu(desc->affinity);
1084
1085                         if (newcpu == NR_CPUS) {
1086                                 if (printk_ratelimit())
1087                                         printk(KERN_INFO "IRQ%u no longer affine to CPU%u\n",
1088                                                i, cpu);
1089
1090                                 cpus_setall(desc->affinity);
1091                                 newcpu = any_online_cpu(desc->affinity);
1092                         }
1093
1094                         route_irq(desc, i, newcpu);
1095                 }
1096         }
1097 }
1098 #endif /* CONFIG_HOTPLUG_CPU */