arch/ppc/kernel/irq.c

   1 /*
   2  *  arch/ppc/kernel/irq.c
   3  *
   4  *  Derived from arch/i386/kernel/irq.c
   5  *    Copyright (C) 1992 Linus Torvalds
   6  *  Adapted from arch/i386 by Gary Thomas
   7  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
   8  *  Updated and modified by Cort Dougan <cort@fsmlabs.com>
   9  *    Copyright (C) 1996-2001 Cort Dougan
  10  *  Adapted for Power Macintosh by Paul Mackerras
  11  *    Copyright (C) 1996 Paul Mackerras (paulus@cs.anu.edu.au)
  12  *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
  13  *
  14  * This file contains the code used by various IRQ handling routines:
  15  * asking for different IRQ's should be done through these routines
  16  * instead of just grabbing them. Thus setups with different IRQ numbers
  17  * shouldn't result in any weird surprises, and installing new handlers
  18  * should be easier.
  19  *
  20  * The MPC8xx has an interrupt mask in the SIU.  If a bit is set, the
  21  * interrupt is _enabled_.  As expected, IRQ0 is bit 0 in the 32-bit
  22  * mask register (of which only 16 are defined), hence the weird shifting
  23  * and complement of the cached_irq_mask.  I want to be able to stuff
  24  * this right into the SIU SMASK register.
  25  * Many of the prep/chrp functions are conditional compiled on CONFIG_8xx
  26  * to reduce code space and undefined function references.
  27  */
  28
  29 #include <linux/errno.h>
  30 #include <linux/module.h>
  31 #include <linux/threads.h>
  32 #include <linux/kernel_stat.h>
  33 #include <linux/signal.h>
  34 #include <linux/sched.h>
  35 #include <linux/ptrace.h>
  36 #include <linux/ioport.h>
  37 #include <linux/interrupt.h>
  38 #include <linux/timex.h>
  39 #include <linux/config.h>
  40 #include <linux/init.h>
  41 #include <linux/slab.h>
  42 #include <linux/pci.h>
  43 #include <linux/delay.h>
  44 #include <linux/irq.h>
  45 #include <linux/proc_fs.h>
  46 #include <linux/random.h>
  47 #include <linux/seq_file.h>
  48 #include <linux/cpumask.h>
  49 #include <linux/profile.h>
  50
  51 #include <asm/uaccess.h>
  52 #include <asm/bitops.h>
  53 #include <asm/system.h>
  54 #include <asm/io.h>
  55 #include <asm/pgtable.h>
  56 #include <asm/irq.h>
  57 #include <asm/cache.h>
  58 #include <asm/prom.h>
  59 #include <asm/ptrace.h>
  60
  61 #define NR_MASK_WORDS   ((NR_IRQS + 31) / 32)
  62
  63 extern atomic_t ipi_recv;
  64 extern atomic_t ipi_sent;
  65 void enable_irq(unsigned int irq_nr);
  66 void disable_irq(unsigned int irq_nr);
  67
  68 static void register_irq_proc (unsigned int irq);
  69
  70 #define MAXCOUNT 10000000
  71
  72 irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned = {
  73         [0 ... NR_IRQS-1] = {
  74                 .lock = SPIN_LOCK_UNLOCKED
  75         }
  76 };
  77
  78 int ppc_spurious_interrupts = 0;
  79 struct irqaction *ppc_irq_action[NR_IRQS];
  80 unsigned long ppc_cached_irq_mask[NR_MASK_WORDS];
  81 unsigned long ppc_lost_interrupts[NR_MASK_WORDS];
  82 atomic_t ppc_n_lost_interrupts;
  83
  84 /* nasty hack for shared irq's since we need to do kmalloc calls but
  85  * can't very early in the boot when we need to do a request irq.
  86  * this needs to be removed.
  87  * -- Cort
  88  */
  89 #define IRQ_KMALLOC_ENTRIES 8
  90 static int cache_bitmask = 0;
  91 static struct irqaction malloc_cache[IRQ_KMALLOC_ENTRIES];
  92 extern int mem_init_done;
  93
  94 #if defined(CONFIG_TAU_INT)
  95 extern int tau_interrupts(unsigned long cpu);
  96 extern int tau_initialized;
  97 #endif
  98
  99 void *irq_kmalloc(size_t size, int pri)
 100 {
 101         unsigned int i;
 102         if ( mem_init_done )
 103                 return kmalloc(size,pri);
 104         for ( i = 0; i < IRQ_KMALLOC_ENTRIES ; i++ )
 105                 if ( ! ( cache_bitmask & (1<<i) ) )
 106                 {
 107                         cache_bitmask |= (1<<i);
 108                         return (void *)(&malloc_cache[i]);
 109                 }
 110         return NULL;
 111 }
 112
 113 void irq_kfree(void *ptr)
 114 {
 115         unsigned int i;
 116         for ( i = 0 ; i < IRQ_KMALLOC_ENTRIES ; i++ )
 117                 if ( ptr == &malloc_cache[i] )
 118                 {
 119                         cache_bitmask &= ~(1<<i);
 120                         return;
 121                 }
 122         kfree(ptr);
 123 }
 124
 125 int
 126 setup_irq(unsigned int irq, struct irqaction * new)
 127 {
 128         int shared = 0;
 129         unsigned long flags;
 130         struct irqaction *old, **p;
 131         irq_desc_t *desc = irq_desc + irq;
 132
 133         /*
 134          * Some drivers like serial.c use request_irq() heavily,
 135          * so we have to be careful not to interfere with a
 136          * running system.
 137          */
 138         if (new->flags & SA_SAMPLE_RANDOM) {
 139                 /*
 140                  * This function might sleep, we want to call it first,
 141                  * outside of the atomic block.
 142                  * Yes, this might clear the entropy pool if the wrong
 143                  * driver is attempted to be loaded, without actually
 144                  * installing a new handler, but is this really a problem,
 145                  * only the sysadmin is able to do this.
 146                  */
 147                 rand_initialize_irq(irq);
 148         }
 149
 150         /*
 151          * The following block of code has to be executed atomically
 152          */
 153         spin_lock_irqsave(&desc->lock,flags);
 154         p = &desc->action;
 155         if ((old = *p) != NULL) {
 156                 /* Can't share interrupts unless both agree to */
 157                 if (!(old->flags & new->flags & SA_SHIRQ)) {
 158                         spin_unlock_irqrestore(&desc->lock,flags);
 159                         return -EBUSY;
 160                 }
 161
 162                 /* add new interrupt at end of irq queue */
 163                 do {
 164                         p = &old->next;
 165                         old = *p;
 166                 } while (old);
 167                 shared = 1;
 168         }
 169
 170         *p = new;
 171
 172         if (!shared) {
 173                 desc->depth = 0;
 174                 desc->status &= ~(IRQ_DISABLED | IRQ_AUTODETECT | IRQ_WAITING);
 175                 if (desc->handler) {
 176                         if (desc->handler->startup)
 177                                 desc->handler->startup(irq);
 178                         else if (desc->handler->enable)
 179                                 desc->handler->enable(irq);
 180                 }
 181         }
 182         spin_unlock_irqrestore(&desc->lock,flags);
 183
 184         register_irq_proc(irq);
 185         return 0;
 186 }
 187
 188 void free_irq(unsigned int irq, void* dev_id)
 189 {
 190         irq_desc_t *desc;
 191         struct irqaction **p;
 192         unsigned long flags;
 193
 194         desc = irq_desc + irq;
 195         spin_lock_irqsave(&desc->lock,flags);
 196         p = &desc->action;
 197         for (;;) {
 198                 struct irqaction * action = *p;
 199                 if (action) {
 200                         struct irqaction **pp = p;
 201                         p = &action->next;
 202                         if (action->dev_id != dev_id)
 203                                 continue;
 204
 205                         /* Found it - now remove it from the list of entries */
 206                         *pp = action->next;
 207                         if (!desc->action) {
 208                                 desc->status |= IRQ_DISABLED;
 209                                 mask_irq(irq);
 210                         }
 211                         spin_unlock_irqrestore(&desc->lock,flags);
 212
 213                         synchronize_irq(irq);
 214                         irq_kfree(action);
 215                         return;
 216                 }
 217                 printk("Trying to free free IRQ%d\n",irq);
 218                 spin_unlock_irqrestore(&desc->lock,flags);
 219                 break;
 220         }
 221         return;
 222 }
 223
 224 EXPORT_SYMBOL(free_irq);
 225
 226 int request_irq(unsigned int irq,
 227         irqreturn_t (*handler)(int, void *, struct pt_regs *),
 228         unsigned long irqflags, const char * devname, void *dev_id)
 229 {
 230         struct irqaction *action;
 231         int retval;
 232
 233         if (irq >= NR_IRQS)
 234                 return -EINVAL;
 235         if (!handler) {
 236                 printk(KERN_ERR "request_irq called with NULL handler!\n");
 237                 dump_stack();
 238                 return 0;
 239         }
 240
 241         action = (struct irqaction *)
 242                 irq_kmalloc(sizeof(struct irqaction), GFP_KERNEL);
 243         if (!action) {
 244                 printk(KERN_ERR "irq_kmalloc() failed for irq %d !\n", irq);
 245                 return -ENOMEM;
 246         }
 247
 248         action->handler = handler;
 249         action->flags = irqflags;
 250         cpus_clear(action->mask);
 251         action->name = devname;
 252         action->dev_id = dev_id;
 253         action->next = NULL;
 254
 255         retval = setup_irq(irq, action);
 256         if (retval) {
 257                 kfree(action);
 258                 return retval;
 259         }
 260
 261         return 0;
 262 }
 263
 264 EXPORT_SYMBOL(request_irq);
 265
 266 /*
 267  * Generic enable/disable code: this just calls
 268  * down into the PIC-specific version for the actual
 269  * hardware disable after having gotten the irq
 270  * controller lock.
 271  */
 272
 273 /**
 274  *      disable_irq_nosync - disable an irq without waiting
 275  *      @irq: Interrupt to disable
 276  *
 277  *      Disable the selected interrupt line. Disables of an interrupt
 278  *      stack. Unlike disable_irq(), this function does not ensure existing
 279  *      instances of the IRQ handler have completed before returning.
 280  *
 281  *      This function may be called from IRQ context.
 282  */
 283
 284 void disable_irq_nosync(unsigned int irq)
 285 {
 286         irq_desc_t *desc = irq_desc + irq;
 287         unsigned long flags;
 288
 289         spin_lock_irqsave(&desc->lock, flags);
 290         if (!desc->depth++) {
 291                 if (!(desc->status & IRQ_PER_CPU))
 292                         desc->status |= IRQ_DISABLED;
 293                 mask_irq(irq);
 294         }
 295         spin_unlock_irqrestore(&desc->lock, flags);
 296 }
 297
 298 /**
 299  *      disable_irq - disable an irq and wait for completion
 300  *      @irq: Interrupt to disable
 301  *
 302  *      Disable the selected interrupt line. Disables of an interrupt
 303  *      stack. That is for two disables you need two enables. This
 304  *      function waits for any pending IRQ handlers for this interrupt
 305  *      to complete before returning. If you use this function while
 306  *      holding a resource the IRQ handler may need you will deadlock.
 307  *
 308  *      This function may be called - with care - from IRQ context.
 309  */
 310
 311 void disable_irq(unsigned int irq)
 312 {
 313         irq_desc_t *desc = irq_desc + irq;
 314         disable_irq_nosync(irq);
 315         if (desc->action)
 316                 synchronize_irq(irq);
 317 }
 318
 319 /**
 320  *      enable_irq - enable interrupt handling on an irq
 321  *      @irq: Interrupt to enable
 322  *
 323  *      Re-enables the processing of interrupts on this IRQ line
 324  *      providing no disable_irq calls are now in effect.
 325  *
 326  *      This function may be called from IRQ context.
 327  */
 328
 329 void enable_irq(unsigned int irq)
 330 {
 331         irq_desc_t *desc = irq_desc + irq;
 332         unsigned long flags;
 333
 334         spin_lock_irqsave(&desc->lock, flags);
 335         switch (desc->depth) {
 336         case 1: {
 337                 unsigned int status = desc->status & ~IRQ_DISABLED;
 338                 desc->status = status;
 339                 if ((status & (IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) {
 340                         desc->status = status | IRQ_REPLAY;
 341                         hw_resend_irq(desc->handler,irq);
 342                 }
 343                 unmask_irq(irq);
 344                 /* fall-through */
 345         }
 346         default:
 347                 desc->depth--;
 348                 break;
 349         case 0:
 350                 printk("enable_irq(%u) unbalanced\n", irq);
 351         }
 352         spin_unlock_irqrestore(&desc->lock, flags);
 353 }
 354
 355 int show_interrupts(struct seq_file *p, void *v)
 356 {
 357         int i = *(loff_t *) v, j;
 358         struct irqaction * action;
 359         unsigned long flags;
 360
 361         if (i == 0) {
 362                 seq_puts(p, "           ");
 363                 for (j=0; j<NR_CPUS; j++)
 364                         if (cpu_online(j))
 365                                 seq_printf(p, "CPU%d       ", j);
 366                 seq_putc(p, '\n');
 367         }
 368
 369         if (i < NR_IRQS) {
 370                 spin_lock_irqsave(&irq_desc[i].lock, flags);
 371                 action = irq_desc[i].action;
 372                 if ( !action || !action->handler )
 373                         goto skip;
 374                 seq_printf(p, "%3d: ", i);
 375 #ifdef CONFIG_SMP
 376                 for (j = 0; j < NR_CPUS; j++)
 377                         if (cpu_online(j))
 378                                 seq_printf(p, "%10u ",
 379                                            kstat_cpu(j).irqs[i]);
 380 #else
 381                 seq_printf(p, "%10u ", kstat_irqs(i));
 382 #endif /* CONFIG_SMP */
 383                 if (irq_desc[i].handler)
 384                         seq_printf(p, " %s ", irq_desc[i].handler->typename);
 385                 else
 386                         seq_puts(p, "  None      ");
 387                 seq_printf(p, "%s", (irq_desc[i].status & IRQ_LEVEL) ? "Level " : "Edge  ");
 388                 seq_printf(p, "    %s", action->name);
 389                 for (action = action->next; action; action = action->next)
 390                         seq_printf(p, ", %s", action->name);
 391                 seq_putc(p, '\n');
 392 skip:
 393                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
 394         } else if (i == NR_IRQS) {
 395 #ifdef CONFIG_TAU_INT
 396                 if (tau_initialized){
 397                         seq_puts(p, "TAU: ");
 398                         for (j = 0; j < NR_CPUS; j++)
 399                                 if (cpu_online(j))
 400                                         seq_printf(p, "%10u ", tau_interrupts(j));
 401                         seq_puts(p, "  PowerPC             Thermal Assist (cpu temp)\n");
 402                 }
 403 #endif
 404 #ifdef CONFIG_SMP
 405                 /* should this be per processor send/receive? */
 406                 seq_printf(p, "IPI (recv/sent): %10u/%u\n",
 407                                 atomic_read(&ipi_recv), atomic_read(&ipi_sent));
 408 #endif
 409                 seq_printf(p, "BAD: %10u\n", ppc_spurious_interrupts);
 410         }
 411         return 0;
 412 }
 413
 414 static inline void
 415 handle_irq_event(int irq, struct pt_regs *regs, struct irqaction *action)
 416 {
 417         int status = 0;
 418         int ret;
 419
 420         if (!(action->flags & SA_INTERRUPT))
 421                 local_irq_enable();
 422
 423         do {
 424                 ret = action->handler(irq, action->dev_id, regs);
 425                 if (ret == IRQ_HANDLED)
 426                         status |= action->flags;
 427                 action = action->next;
 428         } while (action);
 429         if (status & SA_SAMPLE_RANDOM)
 430                 add_interrupt_randomness(irq);
 431         local_irq_disable();
 432 }
 433
 434 /*
 435  * Eventually, this should take an array of interrupts and an array size
 436  * so it can dispatch multiple interrupts.
 437  */
 438 void ppc_irq_dispatch_handler(struct pt_regs *regs, int irq)
 439 {
 440         int status;
 441         struct irqaction *action;
 442         irq_desc_t *desc = irq_desc + irq;
 443
 444         kstat_this_cpu.irqs[irq]++;
 445         spin_lock(&desc->lock);
 446         ack_irq(irq);
 447         /*
 448            REPLAY is when Linux resends an IRQ that was dropped earlier
 449            WAITING is used by probe to mark irqs that are being tested
 450            */
 451         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 452         if (!(status & IRQ_PER_CPU))
 453                 status |= IRQ_PENDING; /* we _want_ to handle it */
 454
 455         /*
 456          * If the IRQ is disabled for whatever reason, we cannot
 457          * use the action we have.
 458          */
 459         action = NULL;
 460         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
 461                 action = desc->action;
 462                 if (!action || !action->handler) {
 463                         ppc_spurious_interrupts++;
 464                         printk(KERN_DEBUG "Unhandled interrupt %x, disabled\n", irq);
 465                         /* We can't call disable_irq here, it would deadlock */
 466                         ++desc->depth;
 467                         desc->status |= IRQ_DISABLED;
 468                         mask_irq(irq);
 469                         /* This is a real interrupt, we have to eoi it,
 470                            so we jump to out */
 471                         goto out;
 472                 }
 473                 status &= ~IRQ_PENDING; /* we commit to handling */
 474                 if (!(status & IRQ_PER_CPU))
 475                         status |= IRQ_INPROGRESS; /* we are handling it */
 476         }
 477         desc->status = status;
 478
 479         /*
 480          * If there is no IRQ handler or it was disabled, exit early.
 481            Since we set PENDING, if another processor is handling
 482            a different instance of this same irq, the other processor
 483            will take care of it.
 484          */
 485         if (unlikely(!action))
 486                 goto out;
 487
 488
 489         /*
 490          * Edge triggered interrupts need to remember
 491          * pending events.
 492          * This applies to any hw interrupts that allow a second
 493          * instance of the same irq to arrive while we are in do_IRQ
 494          * or in the handler. But the code here only handles the _second_
 495          * instance of the irq, not the third or fourth. So it is mostly
 496          * useful for irq hardware that does not mask cleanly in an
 497          * SMP environment.
 498          */
 499         for (;;) {
 500                 spin_unlock(&desc->lock);
 501                 handle_irq_event(irq, regs, action);
 502                 spin_lock(&desc->lock);
 503
 504                 if (likely(!(desc->status & IRQ_PENDING)))
 505                         break;
 506                 desc->status &= ~IRQ_PENDING;
 507         }
 508 out:
 509         desc->status &= ~IRQ_INPROGRESS;
 510         /*
 511          * The ->end() handler has to deal with interrupts which got
 512          * disabled while the handler was running.
 513          */
 514         if (irq_desc[irq].handler) {
 515                 if (irq_desc[irq].handler->end)
 516                         irq_desc[irq].handler->end(irq);
 517                 else if (irq_desc[irq].handler->enable)
 518                         irq_desc[irq].handler->enable(irq);
 519         }
 520         spin_unlock(&desc->lock);
 521 }
 522
 523 void do_IRQ(struct pt_regs *regs)
 524 {
 525         int irq, first = 1;
 526         irq_enter();
 527
 528         /*
 529          * Every platform is required to implement ppc_md.get_irq.
 530          * This function will either return an irq number or -1 to
 531          * indicate there are no more pending.  But the first time
 532          * through the loop this means there wasn't and IRQ pending.
 533          * The value -2 is for buggy hardware and means that this IRQ
 534          * has already been handled. -- Tom
 535          */
 536         while ((irq = ppc_md.get_irq(regs)) >= 0) {
 537                 ppc_irq_dispatch_handler(regs, irq);
 538                 first = 0;
 539         }
 540         if (irq != -2 && first)
 541                 /* That's not SMP safe ... but who cares ? */
 542                 ppc_spurious_interrupts++;
 543         irq_exit();
 544 }
 545
 546 unsigned long probe_irq_on (void)
 547 {
 548         return 0;
 549 }
 550
 551 EXPORT_SYMBOL(probe_irq_on);
 552
 553 int probe_irq_off (unsigned long irqs)
 554 {
 555         return 0;
 556 }
 557
 558 EXPORT_SYMBOL(probe_irq_off);
 559
 560 unsigned int probe_irq_mask(unsigned long irqs)
 561 {
 562         return 0;
 563 }
 564
 565 #ifdef CONFIG_SMP
 566 void synchronize_irq(unsigned int irq)
 567 {
 568         while (irq_desc[irq].status & IRQ_INPROGRESS)
 569                 barrier();
 570 }
 571 #endif /* CONFIG_SMP */
 572
 573 static struct proc_dir_entry *root_irq_dir;
 574 static struct proc_dir_entry *irq_dir[NR_IRQS];
 575 static struct proc_dir_entry *smp_affinity_entry[NR_IRQS];
 576
 577 #ifdef CONFIG_IRQ_ALL_CPUS
 578 #define DEFAULT_CPU_AFFINITY CPU_MASK_ALL
 579 #else
 580 #define DEFAULT_CPU_AFFINITY cpumask_of_cpu(0)
 581 #endif
 582
 583 cpumask_t irq_affinity [NR_IRQS];
 584
 585 static int irq_affinity_read_proc (char *page, char **start, off_t off,
 586                         int count, int *eof, void *data)
 587 {
 588         int len = cpumask_scnprintf(page, count, irq_affinity[(long)data]);
 589         if (count - len < 2)
 590                 return -EINVAL;
 591         len += sprintf(page + len, "\n");
 592         return len;
 593 }
 594
 595 static int irq_affinity_write_proc (struct file *file, const char __user *buffer,
 596                                         unsigned long count, void *data)
 597 {
 598         int irq = (int) data, full_count = count, err;
 599         cpumask_t new_value, tmp;
 600
 601         if (!irq_desc[irq].handler->set_affinity)
 602                 return -EIO;
 603
 604         err = cpumask_parse(buffer, count, new_value);
 605
 606         /*
 607          * Do not allow disabling IRQs completely - it's a too easy
 608          * way to make the system unusable accidentally :-) At least
 609          * one online CPU still has to be targeted.
 610          *
 611          * We assume a 1-1 logical<->physical cpu mapping here.  If
 612          * we assume that the cpu indices in /proc/irq/../smp_affinity
 613          * are actually logical cpu #'s then we have no problem.
 614          *  -- Cort <cort@fsmlabs.com>
 615          */
 616         cpus_and(tmp, new_value, cpu_online_map);
 617         if (cpus_empty(tmp))
 618                 return -EINVAL;
 619
 620         irq_affinity[irq] = new_value;
 621         irq_desc[irq].handler->set_affinity(irq, new_value);
 622
 623         return full_count;
 624 }
 625
 626 #define MAX_NAMELEN 10
 627
 628 static void register_irq_proc (unsigned int irq)
 629 {
 630         struct proc_dir_entry *entry;
 631         char name [MAX_NAMELEN];
 632
 633         if (!root_irq_dir || (irq_desc[irq].handler == NULL) || irq_dir[irq])
 634                 return;
 635
 636         memset(name, 0, MAX_NAMELEN);
 637         sprintf(name, "%d", irq);
 638
 639         /* create /proc/irq/1234 */
 640         irq_dir[irq] = proc_mkdir(name, root_irq_dir);
 641
 642         /* create /proc/irq/1234/smp_affinity */
 643         entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);
 644
 645         entry->nlink = 1;
 646         entry->data = (void *)irq;
 647         entry->read_proc = irq_affinity_read_proc;
 648         entry->write_proc = irq_affinity_write_proc;
 649
 650         smp_affinity_entry[irq] = entry;
 651 }
 652
 653 void init_irq_proc (void)
 654 {
 655         int i;
 656
 657         /* create /proc/irq */
 658         root_irq_dir = proc_mkdir("irq", NULL);
 659         /* create /proc/irq/prof_cpu_mask */
 660         create_prof_cpu_mask(root_irq_dir);
 661
 662         /*
 663          * Create entries for all existing IRQs.
 664          */
 665         for (i = 0; i < NR_IRQS; i++) {
 666                 if (irq_desc[i].handler == NULL)
 667                         continue;
 668                 register_irq_proc(i);
 669         }
 670 }
 671
 672 irqreturn_t no_action(int irq, void *dev, struct pt_regs *regs)
 673 {
 674         return IRQ_NONE;
 675 }
 676
 677 void __init init_IRQ(void)
 678 {
 679         int i;
 680
 681         for (i = 0; i < NR_IRQS; ++i)
 682                 irq_affinity[i] = DEFAULT_CPU_AFFINITY;
 683
 684         ppc_md.init_IRQ();
 685 }