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
  50 #include <asm/uaccess.h>
  51 #include <asm/bitops.h>
  52 #include <asm/system.h>
  53 #include <asm/io.h>
  54 #include <asm/pgtable.h>
  55 #include <asm/irq.h>
  56 #include <asm/cache.h>
  57 #include <asm/prom.h>
  58 #include <asm/ptrace.h>
  59
  60 #define NR_MASK_WORDS   ((NR_IRQS + 31) / 32)
  61
  62 extern atomic_t ipi_recv;
  63 extern atomic_t ipi_sent;
  64 void enable_irq(unsigned int irq_nr);
  65 void disable_irq(unsigned int irq_nr);
  66
  67 static void register_irq_proc (unsigned int irq);
  68
  69 #define MAXCOUNT 10000000
  70
  71 irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned = {
  72         [0 ... NR_IRQS-1] = {
  73                 .lock = SPIN_LOCK_UNLOCKED
  74         }
  75 };
  76
  77 int ppc_spurious_interrupts = 0;
  78 struct irqaction *ppc_irq_action[NR_IRQS];
  79 unsigned long ppc_cached_irq_mask[NR_MASK_WORDS];
  80 unsigned long ppc_lost_interrupts[NR_MASK_WORDS];
  81 atomic_t ppc_n_lost_interrupts;
  82
  83 /* nasty hack for shared irq's since we need to do kmalloc calls but
  84  * can't very early in the boot when we need to do a request irq.
  85  * this needs to be removed.
  86  * -- Cort
  87  */
  88 #define IRQ_KMALLOC_ENTRIES 8
  89 static int cache_bitmask = 0;
  90 static struct irqaction malloc_cache[IRQ_KMALLOC_ENTRIES];
  91 extern int mem_init_done;
  92
  93 #if defined(CONFIG_TAU_INT)
  94 extern int tau_interrupts(unsigned long cpu);
  95 extern int tau_initialized;
  96 #endif
  97
  98 void *irq_kmalloc(size_t size, int pri)
  99 {
 100         unsigned int i;
 101         if ( mem_init_done )
 102                 return kmalloc(size,pri);
 103         for ( i = 0; i < IRQ_KMALLOC_ENTRIES ; i++ )
 104                 if ( ! ( cache_bitmask & (1<<i) ) )
 105                 {
 106                         cache_bitmask |= (1<<i);
 107                         return (void *)(&malloc_cache[i]);
 108                 }
 109         return 0;
 110 }
 111
 112 void irq_kfree(void *ptr)
 113 {
 114         unsigned int i;
 115         for ( i = 0 ; i < IRQ_KMALLOC_ENTRIES ; i++ )
 116                 if ( ptr == &malloc_cache[i] )
 117                 {
 118                         cache_bitmask &= ~(1<<i);
 119                         return;
 120                 }
 121         kfree(ptr);
 122 }
 123
 124 int
 125 setup_irq(unsigned int irq, struct irqaction * new)
 126 {
 127         int shared = 0;
 128         unsigned long flags;
 129         struct irqaction *old, **p;
 130         irq_desc_t *desc = irq_desc + irq;
 131
 132         /*
 133          * Some drivers like serial.c use request_irq() heavily,
 134          * so we have to be careful not to interfere with a
 135          * running system.
 136          */
 137         if (new->flags & SA_SAMPLE_RANDOM) {
 138                 /*
 139                  * This function might sleep, we want to call it first,
 140                  * outside of the atomic block.
 141                  * Yes, this might clear the entropy pool if the wrong
 142                  * driver is attempted to be loaded, without actually
 143                  * installing a new handler, but is this really a problem,
 144                  * only the sysadmin is able to do this.
 145                  */
 146                 rand_initialize_irq(irq);
 147         }
 148
 149         /*
 150          * The following block of code has to be executed atomically
 151          */
 152         spin_lock_irqsave(&desc->lock,flags);
 153         p = &desc->action;
 154         if ((old = *p) != NULL) {
 155                 /* Can't share interrupts unless both agree to */
 156                 if (!(old->flags & new->flags & SA_SHIRQ)) {
 157                         spin_unlock_irqrestore(&desc->lock,flags);
 158                         return -EBUSY;
 159                 }
 160
 161                 /* add new interrupt at end of irq queue */
 162                 do {
 163                         p = &old->next;
 164                         old = *p;
 165                 } while (old);
 166                 shared = 1;
 167         }
 168
 169         *p = new;
 170
 171         if (!shared) {
 172                 desc->depth = 0;
 173                 desc->status &= ~(IRQ_DISABLED | IRQ_AUTODETECT | IRQ_WAITING);
 174                 unmask_irq(irq);
 175         }
 176         spin_unlock_irqrestore(&desc->lock,flags);
 177
 178         register_irq_proc(irq);
 179         return 0;
 180 }
 181
 182 void free_irq(unsigned int irq, void* dev_id)
 183 {
 184         irq_desc_t *desc;
 185         struct irqaction **p;
 186         unsigned long flags;
 187
 188         desc = irq_desc + irq;
 189         spin_lock_irqsave(&desc->lock,flags);
 190         p = &desc->action;
 191         for (;;) {
 192                 struct irqaction * action = *p;
 193                 if (action) {
 194                         struct irqaction **pp = p;
 195                         p = &action->next;
 196                         if (action->dev_id != dev_id)
 197                                 continue;
 198
 199                         /* Found it - now remove it from the list of entries */
 200                         *pp = action->next;
 201                         if (!desc->action) {
 202                                 desc->status |= IRQ_DISABLED;
 203                                 mask_irq(irq);
 204                         }
 205                         spin_unlock_irqrestore(&desc->lock,flags);
 206
 207                         synchronize_irq(irq);
 208                         irq_kfree(action);
 209                         return;
 210                 }
 211                 printk("Trying to free free IRQ%d\n",irq);
 212                 spin_unlock_irqrestore(&desc->lock,flags);
 213                 break;
 214         }
 215         return;
 216 }
 217
 218 EXPORT_SYMBOL(free_irq);
 219
 220 int request_irq(unsigned int irq,
 221         irqreturn_t (*handler)(int, void *, struct pt_regs *),
 222         unsigned long irqflags, const char * devname, void *dev_id)
 223 {
 224         struct irqaction *action;
 225         int retval;
 226
 227         if (irq >= NR_IRQS)
 228                 return -EINVAL;
 229         if (!handler) {
 230                 printk(KERN_ERR "request_irq called with NULL handler!\n");
 231                 dump_stack();
 232                 return 0;
 233         }
 234
 235         action = (struct irqaction *)
 236                 irq_kmalloc(sizeof(struct irqaction), GFP_KERNEL);
 237         if (!action) {
 238                 printk(KERN_ERR "irq_kmalloc() failed for irq %d !\n", irq);
 239                 return -ENOMEM;
 240         }
 241
 242         action->handler = handler;
 243         action->flags = irqflags;
 244         action->mask = 0;
 245         action->name = devname;
 246         action->dev_id = dev_id;
 247         action->next = NULL;
 248
 249         retval = setup_irq(irq, action);
 250         if (retval) {
 251                 kfree(action);
 252                 return retval;
 253         }
 254
 255         return 0;
 256 }
 257
 258 EXPORT_SYMBOL(request_irq);
 259
 260 /*
 261  * Generic enable/disable code: this just calls
 262  * down into the PIC-specific version for the actual
 263  * hardware disable after having gotten the irq
 264  * controller lock.
 265  */
 266
 267 /**
 268  *      disable_irq_nosync - disable an irq without waiting
 269  *      @irq: Interrupt to disable
 270  *
 271  *      Disable the selected interrupt line. Disables of an interrupt
 272  *      stack. Unlike disable_irq(), this function does not ensure existing
 273  *      instances of the IRQ handler have completed before returning.
 274  *
 275  *      This function may be called from IRQ context.
 276  */
 277
 278 void disable_irq_nosync(unsigned int irq)
 279 {
 280         irq_desc_t *desc = irq_desc + irq;
 281         unsigned long flags;
 282
 283         spin_lock_irqsave(&desc->lock, flags);
 284         if (!desc->depth++) {
 285                 if (!(desc->status & IRQ_PER_CPU))
 286                         desc->status |= IRQ_DISABLED;
 287                 mask_irq(irq);
 288         }
 289         spin_unlock_irqrestore(&desc->lock, flags);
 290 }
 291
 292 /**
 293  *      disable_irq - disable an irq and wait for completion
 294  *      @irq: Interrupt to disable
 295  *
 296  *      Disable the selected interrupt line. Disables of an interrupt
 297  *      stack. That is for two disables you need two enables. This
 298  *      function waits for any pending IRQ handlers for this interrupt
 299  *      to complete before returning. If you use this function while
 300  *      holding a resource the IRQ handler may need you will deadlock.
 301  *
 302  *      This function may be called - with care - from IRQ context.
 303  */
 304
 305 void disable_irq(unsigned int irq)
 306 {
 307         irq_desc_t *desc = irq_desc + irq;
 308         disable_irq_nosync(irq);
 309         if (desc->action)
 310                 synchronize_irq(irq);
 311 }
 312
 313 /**
 314  *      enable_irq - enable interrupt handling on an irq
 315  *      @irq: Interrupt to enable
 316  *
 317  *      Re-enables the processing of interrupts on this IRQ line
 318  *      providing no disable_irq calls are now in effect.
 319  *
 320  *      This function may be called from IRQ context.
 321  */
 322
 323 void enable_irq(unsigned int irq)
 324 {
 325         irq_desc_t *desc = irq_desc + irq;
 326         unsigned long flags;
 327
 328         spin_lock_irqsave(&desc->lock, flags);
 329         switch (desc->depth) {
 330         case 1: {
 331                 unsigned int status = desc->status & ~IRQ_DISABLED;
 332                 desc->status = status;
 333                 if ((status & (IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) {
 334                         desc->status = status | IRQ_REPLAY;
 335                         hw_resend_irq(desc->handler,irq);
 336                 }
 337                 unmask_irq(irq);
 338                 /* fall-through */
 339         }
 340         default:
 341                 desc->depth--;
 342                 break;
 343         case 0:
 344                 printk("enable_irq(%u) unbalanced\n", irq);
 345         }
 346         spin_unlock_irqrestore(&desc->lock, flags);
 347 }
 348
 349 int show_interrupts(struct seq_file *p, void *v)
 350 {
 351         int i = *(loff_t *) v, j;
 352         struct irqaction * action;
 353         unsigned long flags;
 354
 355         if (i == 0) {
 356                 seq_puts(p, "           ");
 357                 for (j=0; j<NR_CPUS; j++)
 358                         if (cpu_online(j))
 359                                 seq_printf(p, "CPU%d       ", j);
 360                 seq_putc(p, '\n');
 361         }
 362
 363         if (i < NR_IRQS) {
 364                 spin_lock_irqsave(&irq_desc[i].lock, flags);
 365                 action = irq_desc[i].action;
 366                 if ( !action || !action->handler )
 367                         goto skip;
 368                 seq_printf(p, "%3d: ", i);
 369 #ifdef CONFIG_SMP
 370                 for (j = 0; j < NR_CPUS; j++)
 371                         if (cpu_online(j))
 372                                 seq_printf(p, "%10u ",
 373                                            kstat_cpu(j).irqs[i]);
 374 #else
 375                 seq_printf(p, "%10u ", kstat_irqs(i));
 376 #endif /* CONFIG_SMP */
 377                 if (irq_desc[i].handler)
 378                         seq_printf(p, " %s ", irq_desc[i].handler->typename);
 379                 else
 380                         seq_puts(p, "  None      ");
 381                 seq_printf(p, "%s", (irq_desc[i].status & IRQ_LEVEL) ? "Level " : "Edge  ");
 382                 seq_printf(p, "    %s", action->name);
 383                 for (action = action->next; action; action = action->next)
 384                         seq_printf(p, ", %s", action->name);
 385                 seq_putc(p, '\n');
 386 skip:
 387                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
 388         } else if (i == NR_IRQS) {
 389 #ifdef CONFIG_TAU_INT
 390                 if (tau_initialized){
 391                         seq_puts(p, "TAU: ");
 392                         for (j = 0; j < NR_CPUS; j++)
 393                                 if (cpu_online(j))
 394                                         seq_printf(p, "%10u ", tau_interrupts(j));
 395                         seq_puts(p, "  PowerPC             Thermal Assist (cpu temp)\n");
 396                 }
 397 #endif
 398 #ifdef CONFIG_SMP
 399                 /* should this be per processor send/receive? */
 400                 seq_printf(p, "IPI (recv/sent): %10u/%u\n",
 401                                 atomic_read(&ipi_recv), atomic_read(&ipi_sent));
 402 #endif
 403                 seq_printf(p, "BAD: %10u\n", ppc_spurious_interrupts);
 404         }
 405         return 0;
 406 }
 407
 408 static inline void
 409 handle_irq_event(int irq, struct pt_regs *regs, struct irqaction *action)
 410 {
 411         int status = 0;
 412
 413         if (!(action->flags & SA_INTERRUPT))
 414                 local_irq_enable();
 415
 416         do {
 417                 status |= action->flags;
 418                 action->handler(irq, action->dev_id, regs);
 419                 action = action->next;
 420         } while (action);
 421         if (status & SA_SAMPLE_RANDOM)
 422                 add_interrupt_randomness(irq);
 423         local_irq_disable();
 424 }
 425
 426 /*
 427  * Eventually, this should take an array of interrupts and an array size
 428  * so it can dispatch multiple interrupts.
 429  */
 430 void ppc_irq_dispatch_handler(struct pt_regs *regs, int irq)
 431 {
 432         int status;
 433         struct irqaction *action;
 434         irq_desc_t *desc = irq_desc + irq;
 435
 436         kstat_this_cpu.irqs[irq]++;
 437         spin_lock(&desc->lock);
 438         ack_irq(irq);
 439         /*
 440            REPLAY is when Linux resends an IRQ that was dropped earlier
 441            WAITING is used by probe to mark irqs that are being tested
 442            */
 443         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 444         if (!(status & IRQ_PER_CPU))
 445                 status |= IRQ_PENDING; /* we _want_ to handle it */
 446
 447         /*
 448          * If the IRQ is disabled for whatever reason, we cannot
 449          * use the action we have.
 450          */
 451         action = NULL;
 452         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
 453                 action = desc->action;
 454                 if (!action || !action->handler) {
 455                         ppc_spurious_interrupts++;
 456                         printk(KERN_DEBUG "Unhandled interrupt %x, disabled\n", irq);
 457                         /* We can't call disable_irq here, it would deadlock */
 458                         ++desc->depth;
 459                         desc->status |= IRQ_DISABLED;
 460                         mask_irq(irq);
 461                         /* This is a real interrupt, we have to eoi it,
 462                            so we jump to out */
 463                         goto out;
 464                 }
 465                 status &= ~IRQ_PENDING; /* we commit to handling */
 466                 if (!(status & IRQ_PER_CPU))
 467                         status |= IRQ_INPROGRESS; /* we are handling it */
 468         }
 469         desc->status = status;
 470
 471         /*
 472          * If there is no IRQ handler or it was disabled, exit early.
 473            Since we set PENDING, if another processor is handling
 474            a different instance of this same irq, the other processor
 475            will take care of it.
 476          */
 477         if (unlikely(!action))
 478                 goto out;
 479
 480
 481         /*
 482          * Edge triggered interrupts need to remember
 483          * pending events.
 484          * This applies to any hw interrupts that allow a second
 485          * instance of the same irq to arrive while we are in do_IRQ
 486          * or in the handler. But the code here only handles the _second_
 487          * instance of the irq, not the third or fourth. So it is mostly
 488          * useful for irq hardware that does not mask cleanly in an
 489          * SMP environment.
 490          */
 491         for (;;) {
 492                 spin_unlock(&desc->lock);
 493                 handle_irq_event(irq, regs, action);
 494                 spin_lock(&desc->lock);
 495
 496                 if (likely(!(desc->status & IRQ_PENDING)))
 497                         break;
 498                 desc->status &= ~IRQ_PENDING;
 499         }
 500 out:
 501         desc->status &= ~IRQ_INPROGRESS;
 502         /*
 503          * The ->end() handler has to deal with interrupts which got
 504          * disabled while the handler was running.
 505          */
 506         if (irq_desc[irq].handler) {
 507                 if (irq_desc[irq].handler->end)
 508                         irq_desc[irq].handler->end(irq);
 509                 else if (irq_desc[irq].handler->enable)
 510                         irq_desc[irq].handler->enable(irq);
 511         }
 512         spin_unlock(&desc->lock);
 513 }
 514
 515 void do_IRQ(struct pt_regs *regs)
 516 {
 517         int irq, first = 1;
 518         irq_enter();
 519
 520         /*
 521          * Every platform is required to implement ppc_md.get_irq.
 522          * This function will either return an irq number or -1 to
 523          * indicate there are no more pending.  But the first time
 524          * through the loop this means there wasn't and IRQ pending.
 525          * The value -2 is for buggy hardware and means that this IRQ
 526          * has already been handled. -- Tom
 527          */
 528         while ((irq = ppc_md.get_irq(regs)) >= 0) {
 529                 ppc_irq_dispatch_handler(regs, irq);
 530                 first = 0;
 531         }
 532         if (irq != -2 && first)
 533                 /* That's not SMP safe ... but who cares ? */
 534                 ppc_spurious_interrupts++;
 535         irq_exit();
 536 }
 537
 538 unsigned long probe_irq_on (void)
 539 {
 540         return 0;
 541 }
 542
 543 EXPORT_SYMBOL(probe_irq_on);
 544
 545 int probe_irq_off (unsigned long irqs)
 546 {
 547         return 0;
 548 }
 549
 550 EXPORT_SYMBOL(probe_irq_off);
 551
 552 unsigned int probe_irq_mask(unsigned long irqs)
 553 {
 554         return 0;
 555 }
 556
 557 #ifdef CONFIG_SMP
 558 void synchronize_irq(unsigned int irq)
 559 {
 560         while (irq_desc[irq].status & IRQ_INPROGRESS)
 561                 barrier();
 562 }
 563 #endif /* CONFIG_SMP */
 564
 565 static struct proc_dir_entry *root_irq_dir;
 566 static struct proc_dir_entry *irq_dir[NR_IRQS];
 567 static struct proc_dir_entry *smp_affinity_entry[NR_IRQS];
 568
 569 #ifdef CONFIG_IRQ_ALL_CPUS
 570 #define DEFAULT_CPU_AFFINITY CPU_MASK_ALL
 571 #else
 572 #define DEFAULT_CPU_AFFINITY cpumask_of_cpu(0)
 573 #endif
 574
 575 cpumask_t irq_affinity [NR_IRQS];
 576
 577 static int irq_affinity_read_proc (char *page, char **start, off_t off,
 578                         int count, int *eof, void *data)
 579 {
 580         int len = cpumask_scnprintf(page, count, irq_affinity[(long)data]);
 581         if (count - len < 2)
 582                 return -EINVAL;
 583         len += sprintf(page + len, "\n");
 584         return len;
 585 }
 586
 587 static int irq_affinity_write_proc (struct file *file, const char __user *buffer,
 588                                         unsigned long count, void *data)
 589 {
 590         int irq = (int) data, full_count = count, err;
 591         cpumask_t new_value, tmp;
 592
 593         if (!irq_desc[irq].handler->set_affinity)
 594                 return -EIO;
 595
 596         err = cpumask_parse(buffer, count, new_value);
 597
 598         /*
 599          * Do not allow disabling IRQs completely - it's a too easy
 600          * way to make the system unusable accidentally :-) At least
 601          * one online CPU still has to be targeted.
 602          *
 603          * We assume a 1-1 logical<->physical cpu mapping here.  If
 604          * we assume that the cpu indices in /proc/irq/../smp_affinity
 605          * are actually logical cpu #'s then we have no problem.
 606          *  -- Cort <cort@fsmlabs.com>
 607          */
 608         cpus_and(tmp, new_value, cpu_online_map);
 609         if (cpus_empty(tmp))
 610                 return -EINVAL;
 611
 612         irq_affinity[irq] = new_value;
 613         irq_desc[irq].handler->set_affinity(irq, new_value);
 614
 615         return full_count;
 616 }
 617
 618 static int prof_cpu_mask_read_proc (char *page, char **start, off_t off,
 619                         int count, int *eof, void *data)
 620 {
 621         int len = cpumask_scnprintf(page, count, *(cpumask_t *)data);
 622         if (count - len < 2)
 623                 return -EINVAL;
 624         len += sprintf(page + len, "\n");
 625         return len;
 626 }
 627
 628 static int prof_cpu_mask_write_proc (struct file *file, const char __user *buffer,
 629                                         unsigned long count, void *data)
 630 {
 631         cpumask_t *mask = (cpumask_t *)data, full_count = count, err;
 632         cpumask_t new_value;
 633
 634         err = cpumask_parse(buffer, count, new_value);
 635         if (err)
 636                 return err;
 637
 638         *mask = new_value;
 639         return full_count;
 640 }
 641
 642 #define MAX_NAMELEN 10
 643
 644 static void register_irq_proc (unsigned int irq)
 645 {
 646         struct proc_dir_entry *entry;
 647         char name [MAX_NAMELEN];
 648
 649         if (!root_irq_dir || (irq_desc[irq].handler == NULL) || irq_dir[irq])
 650                 return;
 651
 652         memset(name, 0, MAX_NAMELEN);
 653         sprintf(name, "%d", irq);
 654
 655         /* create /proc/irq/1234 */
 656         irq_dir[irq] = proc_mkdir(name, root_irq_dir);
 657
 658         /* create /proc/irq/1234/smp_affinity */
 659         entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);
 660
 661         entry->nlink = 1;
 662         entry->data = (void *)irq;
 663         entry->read_proc = irq_affinity_read_proc;
 664         entry->write_proc = irq_affinity_write_proc;
 665
 666         smp_affinity_entry[irq] = entry;
 667 }
 668
 669 unsigned long prof_cpu_mask = -1;
 670
 671 void init_irq_proc (void)
 672 {
 673         struct proc_dir_entry *entry;
 674         int i;
 675
 676         /* create /proc/irq */
 677         root_irq_dir = proc_mkdir("irq", 0);
 678
 679         /* create /proc/irq/prof_cpu_mask */
 680         entry = create_proc_entry("prof_cpu_mask", 0600, root_irq_dir);
 681
 682         entry->nlink = 1;
 683         entry->data = (void *)&prof_cpu_mask;
 684         entry->read_proc = prof_cpu_mask_read_proc;
 685         entry->write_proc = prof_cpu_mask_write_proc;
 686
 687         /*
 688          * Create entries for all existing IRQs.
 689          */
 690         for (i = 0; i < NR_IRQS; i++) {
 691                 if (irq_desc[i].handler == NULL)
 692                         continue;
 693                 register_irq_proc(i);
 694         }
 695 }
 696
 697 irqreturn_t no_action(int irq, void *dev, struct pt_regs *regs)
 698 {
 699         return IRQ_NONE;
 700 }
 701
 702 void __init init_IRQ(void)
 703 {
 704         int i;
 705
 706         for (i = 0; i < NR_IRQS; ++i)
 707                 irq_affinity[i] = DEFAULT_CPU_AFFINITY;
 708
 709         ppc_md.init_IRQ();
 710 }