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