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 (!count || noirqdebug)
 309                 return;
 310
 311         count--;
 312
 313         if (ret != IRQ_HANDLED && ret != IRQ_NONE) {
 314                 printk("irq%u: bogus retval mask %x\n", irq, ret);
 315         } else {
 316                 printk("irq%u: nobody cared\n", irq);
 317         }
 318         show_regs(regs);
 319         dump_stack();
 320         printk(KERN_ERR "handlers:");
 321         action = desc->action;
 322         do {
 323                 printk("\n" KERN_ERR "[<%p>]", action->handler);
 324                 print_symbol(" (%s)", (unsigned long)action->handler);
 325                 action = action->next;
 326         } while (action);
 327         printk("\n");
 328 }
 329
 330 static int
 331 __do_irq(unsigned int irq, struct irqaction *action, struct pt_regs *regs)
 332 {
 333         unsigned int status;
 334         int ret, retval = 0;
 335
 336         spin_unlock(&irq_controller_lock);
 337
 338 #ifdef CONFIG_NO_IDLE_HZ
 339         if (!(action->flags & SA_TIMER) && system_timer->dyn_tick != NULL) {
 340                 write_seqlock(&xtime_lock);
 341                 if (system_timer->dyn_tick->state & DYN_TICK_ENABLED)
 342                         system_timer->dyn_tick->handler(irq, 0, regs);
 343                 write_sequnlock(&xtime_lock);
 344         }
 345 #endif
 346
 347         if (!(action->flags & SA_INTERRUPT))
 348                 local_irq_enable();
 349
 350         status = 0;
 351         do {
 352                 ret = action->handler(irq, action->dev_id, regs);
 353                 if (ret == IRQ_HANDLED)
 354                         status |= action->flags;
 355                 retval |= ret;
 356                 action = action->next;
 357         } while (action);
 358
 359         if (status & SA_SAMPLE_RANDOM)
 360                 add_interrupt_randomness(irq);
 361
 362         spin_lock_irq(&irq_controller_lock);
 363
 364         return retval;
 365 }
 366
 367 /*
 368  * This is for software-decoded IRQs.  The caller is expected to
 369  * handle the ack, clear, mask and unmask issues.
 370  */
 371 void
 372 do_simple_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
 373 {
 374         struct irqaction *action;
 375         const unsigned int cpu = smp_processor_id();
 376
 377         desc->triggered = 1;
 378
 379         kstat_cpu(cpu).irqs[irq]++;
 380
 381         smp_set_running(desc);
 382
 383         action = desc->action;
 384         if (action) {
 385                 int ret = __do_irq(irq, action, regs);
 386                 if (ret != IRQ_HANDLED)
 387                         report_bad_irq(irq, regs, desc, ret);
 388         }
 389
 390         smp_clear_running(desc);
 391 }
 392
 393 /*
 394  * Most edge-triggered IRQ implementations seem to take a broken
 395  * approach to this.  Hence the complexity.
 396  */
 397 void
 398 do_edge_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
 399 {
 400         const unsigned int cpu = smp_processor_id();
 401
 402         desc->triggered = 1;
 403
 404         /*
 405          * If we're currently running this IRQ, or its disabled,
 406          * we shouldn't process the IRQ.  Instead, turn on the
 407          * hardware masks.
 408          */
 409         if (unlikely(desc->running || desc->disable_depth))
 410                 goto running;
 411
 412         /*
 413          * Acknowledge and clear the IRQ, but don't mask it.
 414          */
 415         desc->chip->ack(irq);
 416
 417         /*
 418          * Mark the IRQ currently in progress.
 419          */
 420         desc->running = 1;
 421
 422         kstat_cpu(cpu).irqs[irq]++;
 423
 424         do {
 425                 struct irqaction *action;
 426
 427                 action = desc->action;
 428                 if (!action)
 429                         break;
 430
 431                 if (desc->pending && !desc->disable_depth) {
 432                         desc->pending = 0;
 433                         desc->chip->unmask(irq);
 434                 }
 435
 436                 __do_irq(irq, action, regs);
 437         } while (desc->pending && !desc->disable_depth);
 438
 439         desc->running = 0;
 440
 441         /*
 442          * If we were disabled or freed, shut down the handler.
 443          */
 444         if (likely(desc->action && !check_irq_lock(desc, irq, regs)))
 445                 return;
 446
 447  running:
 448         /*
 449          * We got another IRQ while this one was masked or
 450          * currently running.  Delay it.
 451          */
 452         desc->pending = 1;
 453         desc->chip->mask(irq);
 454         desc->chip->ack(irq);
 455 }
 456
 457 /*
 458  * Level-based IRQ handler.  Nice and simple.
 459  */
 460 void
 461 do_level_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
 462 {
 463         struct irqaction *action;
 464         const unsigned int cpu = smp_processor_id();
 465
 466         desc->triggered = 1;
 467
 468         /*
 469          * Acknowledge, clear _AND_ disable the interrupt.
 470          */
 471         desc->chip->ack(irq);
 472
 473         if (likely(!desc->disable_depth)) {
 474                 kstat_cpu(cpu).irqs[irq]++;
 475
 476                 smp_set_running(desc);
 477
 478                 /*
 479                  * Return with this interrupt masked if no action
 480                  */
 481                 action = desc->action;
 482                 if (action) {
 483                         int ret = __do_irq(irq, desc->action, regs);
 484
 485                         if (ret != IRQ_HANDLED)
 486                                 report_bad_irq(irq, regs, desc, ret);
 487
 488                         if (likely(!desc->disable_depth &&
 489                                    !check_irq_lock(desc, irq, regs)))
 490                                 desc->chip->unmask(irq);
 491                 }
 492
 493                 smp_clear_running(desc);
 494         }
 495 }
 496
 497 static void do_pending_irqs(struct pt_regs *regs)
 498 {
 499         struct list_head head, *l, *n;
 500
 501         do {
 502                 struct irqdesc *desc;
 503
 504                 /*
 505                  * First, take the pending interrupts off the list.
 506                  * The act of calling the handlers may add some IRQs
 507                  * back onto the list.
 508                  */
 509                 head = irq_pending;
 510                 INIT_LIST_HEAD(&irq_pending);
 511                 head.next->prev = &head;
 512                 head.prev->next = &head;
 513
 514                 /*
 515                  * Now run each entry.  We must delete it from our
 516                  * list before calling the handler.
 517                  */
 518                 list_for_each_safe(l, n, &head) {
 519                         desc = list_entry(l, struct irqdesc, pend);
 520                         list_del_init(&desc->pend);
 521                         desc_handle_irq(desc - irq_desc, desc, regs);
 522                 }
 523
 524                 /*
 525                  * The list must be empty.
 526                  */
 527                 BUG_ON(!list_empty(&head));
 528         } while (!list_empty(&irq_pending));
 529 }
 530
 531 /*
 532  * do_IRQ handles all hardware IRQ's.  Decoded IRQs should not
 533  * come via this function.  Instead, they should provide their
 534  * own 'handler'
 535  */
 536 asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
 537 {
 538         struct irqdesc *desc = irq_desc + irq;
 539
 540         /*
 541          * Some hardware gives randomly wrong interrupts.  Rather
 542          * than crashing, do something sensible.
 543          */
 544         if (irq >= NR_IRQS)
 545                 desc = &bad_irq_desc;
 546
 547         irq_enter();
 548         spin_lock(&irq_controller_lock);
 549         desc_handle_irq(irq, desc, regs);
 550
 551         /*
 552          * Now re-run any pending interrupts.
 553          */
 554         if (!list_empty(&irq_pending))
 555                 do_pending_irqs(regs);
 556
 557         irq_finish(irq);
 558
 559         spin_unlock(&irq_controller_lock);
 560         irq_exit();
 561 }
 562
 563 void __set_irq_handler(unsigned int irq, irq_handler_t handle, int is_chained)
 564 {
 565         struct irqdesc *desc;
 566         unsigned long flags;
 567
 568         if (irq >= NR_IRQS) {
 569                 printk(KERN_ERR "Trying to install handler for IRQ%d\n", irq);
 570                 return;
 571         }
 572
 573         if (handle == NULL)
 574                 handle = do_bad_IRQ;
 575
 576         desc = irq_desc + irq;
 577
 578         if (is_chained && desc->chip == &bad_chip)
 579                 printk(KERN_WARNING "Trying to install chained handler for IRQ%d\n", irq);
 580
 581         spin_lock_irqsave(&irq_controller_lock, flags);
 582         if (handle == do_bad_IRQ) {
 583                 desc->chip->mask(irq);
 584                 desc->chip->ack(irq);
 585                 desc->disable_depth = 1;
 586         }
 587         desc->handle = handle;
 588         if (handle != do_bad_IRQ && is_chained) {
 589                 desc->valid = 0;
 590                 desc->probe_ok = 0;
 591                 desc->disable_depth = 0;
 592                 desc->chip->unmask(irq);
 593         }
 594         spin_unlock_irqrestore(&irq_controller_lock, flags);
 595 }
 596
 597 void set_irq_chip(unsigned int irq, struct irqchip *chip)
 598 {
 599         struct irqdesc *desc;
 600         unsigned long flags;
 601
 602         if (irq >= NR_IRQS) {
 603                 printk(KERN_ERR "Trying to install chip for IRQ%d\n", irq);
 604                 return;
 605         }
 606
 607         if (chip == NULL)
 608                 chip = &bad_chip;
 609
 610         desc = irq_desc + irq;
 611         spin_lock_irqsave(&irq_controller_lock, flags);
 612         desc->chip = chip;
 613         spin_unlock_irqrestore(&irq_controller_lock, flags);
 614 }
 615
 616 int set_irq_type(unsigned int irq, unsigned int type)
 617 {
 618         struct irqdesc *desc;
 619         unsigned long flags;
 620         int ret = -ENXIO;
 621
 622         if (irq >= NR_IRQS) {
 623                 printk(KERN_ERR "Trying to set irq type for IRQ%d\n", irq);
 624                 return -ENODEV;
 625         }
 626
 627         desc = irq_desc + irq;
 628         if (desc->chip->set_type) {
 629                 spin_lock_irqsave(&irq_controller_lock, flags);
 630                 ret = desc->chip->set_type(irq, type);
 631                 spin_unlock_irqrestore(&irq_controller_lock, flags);
 632         }
 633
 634         return ret;
 635 }
 636 EXPORT_SYMBOL(set_irq_type);
 637
 638 void set_irq_flags(unsigned int irq, unsigned int iflags)
 639 {
 640         struct irqdesc *desc;
 641         unsigned long flags;
 642
 643         if (irq >= NR_IRQS) {
 644                 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
 645                 return;
 646         }
 647
 648         desc = irq_desc + irq;
 649         spin_lock_irqsave(&irq_controller_lock, flags);
 650         desc->valid = (iflags & IRQF_VALID) != 0;
 651         desc->probe_ok = (iflags & IRQF_PROBE) != 0;
 652         desc->noautoenable = (iflags & IRQF_NOAUTOEN) != 0;
 653         spin_unlock_irqrestore(&irq_controller_lock, flags);
 654 }
 655
 656 int setup_irq(unsigned int irq, struct irqaction *new)
 657 {
 658         int shared = 0;
 659         struct irqaction *old, **p;
 660         unsigned long flags;
 661         struct irqdesc *desc;
 662
 663         /*
 664          * Some drivers like serial.c use request_irq() heavily,
 665          * so we have to be careful not to interfere with a
 666          * running system.
 667          */
 668         if (new->flags & SA_SAMPLE_RANDOM) {
 669                 /*
 670                  * This function might sleep, we want to call it first,
 671                  * outside of the atomic block.
 672                  * Yes, this might clear the entropy pool if the wrong
 673                  * driver is attempted to be loaded, without actually
 674                  * installing a new handler, but is this really a problem,
 675                  * only the sysadmin is able to do this.
 676                  */
 677                 rand_initialize_irq(irq);
 678         }
 679
 680         /*
 681          * The following block of code has to be executed atomically
 682          */
 683         desc = irq_desc + irq;
 684         spin_lock_irqsave(&irq_controller_lock, flags);
 685         p = &desc->action;
 686         if ((old = *p) != NULL) {
 687                 /*
 688                  * Can't share interrupts unless both agree to and are
 689                  * the same type.
 690                  */
 691                 if (!(old->flags & new->flags & SA_SHIRQ) ||
 692                     (~old->flags & new->flags) & SA_TRIGGER_MASK) {
 693                         spin_unlock_irqrestore(&irq_controller_lock, flags);
 694                         return -EBUSY;
 695                 }
 696
 697                 /* add new interrupt at end of irq queue */
 698                 do {
 699                         p = &old->next;
 700                         old = *p;
 701                 } while (old);
 702                 shared = 1;
 703         }
 704
 705         *p = new;
 706
 707         if (!shared) {
 708                 desc->probing = 0;
 709                 desc->running = 0;
 710                 desc->pending = 0;
 711                 desc->disable_depth = 1;
 712
 713                 if (new->flags & SA_TRIGGER_MASK) {
 714                         unsigned int type = new->flags & SA_TRIGGER_MASK;
 715                         desc->chip->set_type(irq, type);
 716                 }
 717
 718                 if (!desc->noautoenable) {
 719                         desc->disable_depth = 0;
 720                         desc->chip->unmask(irq);
 721                 }
 722         }
 723
 724         spin_unlock_irqrestore(&irq_controller_lock, flags);
 725         return 0;
 726 }
 727
 728 /**
 729  *      request_irq - allocate an interrupt line
 730  *      @irq: Interrupt line to allocate
 731  *      @handler: Function to be called when the IRQ occurs
 732  *      @irqflags: Interrupt type flags
 733  *      @devname: An ascii name for the claiming device
 734  *      @dev_id: A cookie passed back to the handler function
 735  *
 736  *      This call allocates interrupt resources and enables the
 737  *      interrupt line and IRQ handling. From the point this
 738  *      call is made your handler function may be invoked. Since
 739  *      your handler function must clear any interrupt the board
 740  *      raises, you must take care both to initialise your hardware
 741  *      and to set up the interrupt handler in the right order.
 742  *
 743  *      Dev_id must be globally unique. Normally the address of the
 744  *      device data structure is used as the cookie. Since the handler
 745  *      receives this value it makes sense to use it.
 746  *
 747  *      If your interrupt is shared you must pass a non NULL dev_id
 748  *      as this is required when freeing the interrupt.
 749  *
 750  *      Flags:
 751  *
 752  *      SA_SHIRQ                Interrupt is shared
 753  *
 754  *      SA_INTERRUPT            Disable local interrupts while processing
 755  *
 756  *      SA_SAMPLE_RANDOM        The interrupt can be used for entropy
 757  *
 758  */
 759 int request_irq(unsigned int irq, irqreturn_t (*handler)(int, void *, struct pt_regs *),
 760                  unsigned long irq_flags, const char * devname, void *dev_id)
 761 {
 762         unsigned long retval;
 763         struct irqaction *action;
 764
 765         if (irq >= NR_IRQS || !irq_desc[irq].valid || !handler ||
 766             (irq_flags & SA_SHIRQ && !dev_id))
 767                 return -EINVAL;
 768
 769         action = (struct irqaction *)kmalloc(sizeof(struct irqaction), GFP_KERNEL);
 770         if (!action)
 771                 return -ENOMEM;
 772
 773         action->handler = handler;
 774         action->flags = irq_flags;
 775         cpus_clear(action->mask);
 776         action->name = devname;
 777         action->next = NULL;
 778         action->dev_id = dev_id;
 779
 780         retval = setup_irq(irq, action);
 781
 782         if (retval)
 783                 kfree(action);
 784         return retval;
 785 }
 786
 787 EXPORT_SYMBOL(request_irq);
 788
 789 /**
 790  *      free_irq - free an interrupt
 791  *      @irq: Interrupt line to free
 792  *      @dev_id: Device identity to free
 793  *
 794  *      Remove an interrupt handler. The handler is removed and if the
 795  *      interrupt line is no longer in use by any driver it is disabled.
 796  *      On a shared IRQ the caller must ensure the interrupt is disabled
 797  *      on the card it drives before calling this function.
 798  *
 799  *      This function must not be called from interrupt context.
 800  */
 801 void free_irq(unsigned int irq, void *dev_id)
 802 {
 803         struct irqaction * action, **p;
 804         unsigned long flags;
 805
 806         if (irq >= NR_IRQS || !irq_desc[irq].valid) {
 807                 printk(KERN_ERR "Trying to free IRQ%d\n",irq);
 808                 dump_stack();
 809                 return;
 810         }
 811
 812         spin_lock_irqsave(&irq_controller_lock, flags);
 813         for (p = &irq_desc[irq].action; (action = *p) != NULL; p = &action->next) {
 814                 if (action->dev_id != dev_id)
 815                         continue;
 816
 817                 /* Found it - now free it */
 818                 *p = action->next;
 819                 break;
 820         }
 821         spin_unlock_irqrestore(&irq_controller_lock, flags);
 822
 823         if (!action) {
 824                 printk(KERN_ERR "Trying to free free IRQ%d\n",irq);
 825                 dump_stack();
 826         } else {
 827                 synchronize_irq(irq);
 828                 kfree(action);
 829         }
 830 }
 831
 832 EXPORT_SYMBOL(free_irq);
 833
 834 static DECLARE_MUTEX(probe_sem);
 835
 836 /* Start the interrupt probing.  Unlike other architectures,
 837  * we don't return a mask of interrupts from probe_irq_on,
 838  * but return the number of interrupts enabled for the probe.
 839  * The interrupts which have been enabled for probing is
 840  * instead recorded in the irq_desc structure.
 841  */
 842 unsigned long probe_irq_on(void)
 843 {
 844         unsigned int i, irqs = 0;
 845         unsigned long delay;
 846
 847         down(&probe_sem);
 848
 849         /*
 850          * first snaffle up any unassigned but
 851          * probe-able interrupts
 852          */
 853         spin_lock_irq(&irq_controller_lock);
 854         for (i = 0; i < NR_IRQS; i++) {
 855                 if (!irq_desc[i].probe_ok || irq_desc[i].action)
 856                         continue;
 857
 858                 irq_desc[i].probing = 1;
 859                 irq_desc[i].triggered = 0;
 860                 if (irq_desc[i].chip->set_type)
 861                         irq_desc[i].chip->set_type(i, IRQT_PROBE);
 862                 irq_desc[i].chip->unmask(i);
 863                 irqs += 1;
 864         }
 865         spin_unlock_irq(&irq_controller_lock);
 866
 867         /*
 868          * wait for spurious interrupts to mask themselves out again
 869          */
 870         for (delay = jiffies + HZ/10; time_before(jiffies, delay); )
 871                 /* min 100ms delay */;
 872
 873         /*
 874          * now filter out any obviously spurious interrupts
 875          */
 876         spin_lock_irq(&irq_controller_lock);
 877         for (i = 0; i < NR_IRQS; i++) {
 878                 if (irq_desc[i].probing && irq_desc[i].triggered) {
 879                         irq_desc[i].probing = 0;
 880                         irqs -= 1;
 881                 }
 882         }
 883         spin_unlock_irq(&irq_controller_lock);
 884
 885         return irqs;
 886 }
 887
 888 EXPORT_SYMBOL(probe_irq_on);
 889
 890 unsigned int probe_irq_mask(unsigned long irqs)
 891 {
 892         unsigned int mask = 0, i;
 893
 894         spin_lock_irq(&irq_controller_lock);
 895         for (i = 0; i < 16 && i < NR_IRQS; i++)
 896                 if (irq_desc[i].probing && irq_desc[i].triggered)
 897                         mask |= 1 << i;
 898         spin_unlock_irq(&irq_controller_lock);
 899
 900         up(&probe_sem);
 901
 902         return mask;
 903 }
 904 EXPORT_SYMBOL(probe_irq_mask);
 905
 906 /*
 907  * Possible return values:
 908  *  >= 0 - interrupt number
 909  *    -1 - no interrupt/many interrupts
 910  */
 911 int probe_irq_off(unsigned long irqs)
 912 {
 913         unsigned int i;
 914         int irq_found = NO_IRQ;
 915
 916         /*
 917          * look at the interrupts, and find exactly one
 918          * that we were probing has been triggered
 919          */
 920         spin_lock_irq(&irq_controller_lock);
 921         for (i = 0; i < NR_IRQS; i++) {
 922                 if (irq_desc[i].probing &&
 923                     irq_desc[i].triggered) {
 924                         if (irq_found != NO_IRQ) {
 925                                 irq_found = NO_IRQ;
 926                                 goto out;
 927                         }
 928                         irq_found = i;
 929                 }
 930         }
 931
 932         if (irq_found == -1)
 933                 irq_found = NO_IRQ;
 934 out:
 935         spin_unlock_irq(&irq_controller_lock);
 936
 937         up(&probe_sem);
 938
 939         return irq_found;
 940 }
 941
 942 EXPORT_SYMBOL(probe_irq_off);
 943
 944 #ifdef CONFIG_SMP
 945 static void route_irq(struct irqdesc *desc, unsigned int irq, unsigned int cpu)
 946 {
 947         pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", irq, desc->cpu, cpu);
 948
 949         spin_lock_irq(&irq_controller_lock);
 950         desc->cpu = cpu;
 951         desc->chip->set_cpu(desc, irq, cpu);
 952         spin_unlock_irq(&irq_controller_lock);
 953 }
 954
 955 #ifdef CONFIG_PROC_FS
 956 static int
 957 irq_affinity_read_proc(char *page, char **start, off_t off, int count,
 958                        int *eof, void *data)
 959 {
 960         struct irqdesc *desc = irq_desc + ((int)data);
 961         int len = cpumask_scnprintf(page, count, desc->affinity);
 962
 963         if (count - len < 2)
 964                 return -EINVAL;
 965         page[len++] = '\n';
 966         page[len] = '\0';
 967
 968         return len;
 969 }
 970
 971 static int
 972 irq_affinity_write_proc(struct file *file, const char __user *buffer,
 973                         unsigned long count, void *data)
 974 {
 975         unsigned int irq = (unsigned int)data;
 976         struct irqdesc *desc = irq_desc + irq;
 977         cpumask_t affinity, tmp;
 978         int ret = -EIO;
 979
 980         if (!desc->chip->set_cpu)
 981                 goto out;
 982
 983         ret = cpumask_parse(buffer, count, affinity);
 984         if (ret)
 985                 goto out;
 986
 987         cpus_and(tmp, affinity, cpu_online_map);
 988         if (cpus_empty(tmp)) {
 989                 ret = -EINVAL;
 990                 goto out;
 991         }
 992
 993         desc->affinity = affinity;
 994         route_irq(desc, irq, first_cpu(tmp));
 995         ret = count;
 996
 997  out:
 998         return ret;
 999 }
1000 #endif
1001 #endif
1002
1003 void __init init_irq_proc(void)
1004 {
1005 #if defined(CONFIG_SMP) && defined(CONFIG_PROC_FS)
1006         struct proc_dir_entry *dir;
1007         int irq;
1008
1009         dir = proc_mkdir("irq", NULL);
1010         if (!dir)
1011                 return;
1012
1013         for (irq = 0; irq < NR_IRQS; irq++) {
1014                 struct proc_dir_entry *entry;
1015                 struct irqdesc *desc;
1016                 char name[16];
1017
1018                 desc = irq_desc + irq;
1019                 memset(name, 0, sizeof(name));
1020                 snprintf(name, sizeof(name) - 1, "%u", irq);
1021
1022                 desc->procdir = proc_mkdir(name, dir);
1023                 if (!desc->procdir)
1024                         continue;
1025
1026                 entry = create_proc_entry("smp_affinity", 0600, desc->procdir);
1027                 if (entry) {
1028                         entry->nlink = 1;
1029                         entry->data = (void *)irq;
1030                         entry->read_proc = irq_affinity_read_proc;
1031                         entry->write_proc = irq_affinity_write_proc;
1032                 }
1033         }
1034 #endif
1035 }
1036
1037 void __init init_IRQ(void)
1038 {
1039         struct irqdesc *desc;
1040         int irq;
1041
1042 #ifdef CONFIG_SMP
1043         bad_irq_desc.affinity = CPU_MASK_ALL;
1044         bad_irq_desc.cpu = smp_processor_id();
1045 #endif
1046
1047         for (irq = 0, desc = irq_desc; irq < NR_IRQS; irq++, desc++) {
1048                 *desc = bad_irq_desc;
1049                 INIT_LIST_HEAD(&desc->pend);
1050         }
1051
1052         init_arch_irq();
1053 }
1054
1055 static int __init noirqdebug_setup(char *str)
1056 {
1057         noirqdebug = 1;
1058         return 1;
1059 }
1060
1061 __setup("noirqdebug", noirqdebug_setup);
1062
1063 #ifdef CONFIG_HOTPLUG_CPU
1064 /*
1065  * The CPU has been marked offline.  Migrate IRQs off this CPU.  If
1066  * the affinity settings do not allow other CPUs, force them onto any
1067  * available CPU.
1068  */
1069 void migrate_irqs(void)
1070 {
1071         unsigned int i, cpu = smp_processor_id();
1072
1073         for (i = 0; i < NR_IRQS; i++) {
1074                 struct irqdesc *desc = irq_desc + i;
1075
1076                 if (desc->cpu == cpu) {
1077                         unsigned int newcpu = any_online_cpu(desc->affinity);
1078
1079                         if (newcpu == NR_CPUS) {
1080                                 if (printk_ratelimit())
1081                                         printk(KERN_INFO "IRQ%u no longer affine to CPU%u\n",
1082                                                i, cpu);
1083
1084                                 cpus_setall(desc->affinity);
1085                                 newcpu = any_online_cpu(desc->affinity);
1086                         }
1087
1088                         route_irq(desc, i, newcpu);
1089                 }
1090         }
1091 }
1092 #endif /* CONFIG_HOTPLUG_CPU */