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