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 NULL;
 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                 if (desc->handler) {
 175                         if (desc->handler->startup)
 176                                 desc->handler->startup(irq);
 177                         else if (desc->handler->enable)
 178                                 desc->handler->enable(irq);
 179                 }
 180         }
 181         spin_unlock_irqrestore(&desc->lock,flags);
 182
 183         register_irq_proc(irq);
 184         return 0;
 185 }
 186
 187 void free_irq(unsigned int irq, void* dev_id)
 188 {
 189         irq_desc_t *desc;
 190         struct irqaction **p;
 191         unsigned long flags;
 192
 193         desc = irq_desc + irq;
 194         spin_lock_irqsave(&desc->lock,flags);
 195         p = &desc->action;
 196         for (;;) {
 197                 struct irqaction * action = *p;
 198                 if (action) {
 199                         struct irqaction **pp = p;
 200                         p = &action->next;
 201                         if (action->dev_id != dev_id)
 202                                 continue;
 203
 204                         /* Found it - now remove it from the list of entries */
 205                         *pp = action->next;
 206                         if (!desc->action) {
 207                                 desc->status |= IRQ_DISABLED;
 208                                 mask_irq(irq);
 209                         }
 210                         spin_unlock_irqrestore(&desc->lock,flags);
 211
 212                         synchronize_irq(irq);
 213                         irq_kfree(action);
 214                         return;
 215                 }
 216                 printk("Trying to free free IRQ%d\n",irq);
 217                 spin_unlock_irqrestore(&desc->lock,flags);
 218                 break;
 219         }
 220         return;
 221 }
 222
 223 EXPORT_SYMBOL(free_irq);
 224
 225 int request_irq(unsigned int irq,
 226         irqreturn_t (*handler)(int, void *, struct pt_regs *),
 227         unsigned long irqflags, const char * devname, void *dev_id)
 228 {
 229         struct irqaction *action;
 230         int retval;
 231
 232         if (irq >= NR_IRQS)
 233                 return -EINVAL;
 234         if (!handler) {
 235                 printk(KERN_ERR "request_irq called with NULL handler!\n");
 236                 dump_stack();
 237                 return 0;
 238         }
 239
 240         action = (struct irqaction *)
 241                 irq_kmalloc(sizeof(struct irqaction), GFP_KERNEL);
 242         if (!action) {
 243                 printk(KERN_ERR "irq_kmalloc() failed for irq %d !\n", irq);
 244                 return -ENOMEM;
 245         }
 246
 247         action->handler = handler;
 248         action->flags = irqflags;
 249         cpus_clear(action->mask);
 250         action->name = devname;
 251         action->dev_id = dev_id;
 252         action->next = NULL;
 253
 254         retval = setup_irq(irq, action);
 255         if (retval) {
 256                 kfree(action);
 257                 return retval;
 258         }
 259
 260         return 0;
 261 }
 262
 263 EXPORT_SYMBOL(request_irq);
 264
 265 /*
 266  * Generic enable/disable code: this just calls
 267  * down into the PIC-specific version for the actual
 268  * hardware disable after having gotten the irq
 269  * controller lock.
 270  */
 271
 272 /**
 273  *      disable_irq_nosync - disable an irq without waiting
 274  *      @irq: Interrupt to disable
 275  *
 276  *      Disable the selected interrupt line. Disables of an interrupt
 277  *      stack. Unlike disable_irq(), this function does not ensure existing
 278  *      instances of the IRQ handler have completed before returning.
 279  *
 280  *      This function may be called from IRQ context.
 281  */
 282
 283 void disable_irq_nosync(unsigned int irq)
 284 {
 285         irq_desc_t *desc = irq_desc + irq;
 286         unsigned long flags;
 287
 288         spin_lock_irqsave(&desc->lock, flags);
 289         if (!desc->depth++) {
 290                 if (!(desc->status & IRQ_PER_CPU))
 291                         desc->status |= IRQ_DISABLED;
 292                 mask_irq(irq);
 293         }
 294         spin_unlock_irqrestore(&desc->lock, flags);
 295 }
 296
 297 /**
 298  *      disable_irq - disable an irq and wait for completion
 299  *      @irq: Interrupt to disable
 300  *
 301  *      Disable the selected interrupt line. Disables of an interrupt
 302  *      stack. That is for two disables you need two enables. This
 303  *      function waits for any pending IRQ handlers for this interrupt
 304  *      to complete before returning. If you use this function while
 305  *      holding a resource the IRQ handler may need you will deadlock.
 306  *
 307  *      This function may be called - with care - from IRQ context.
 308  */
 309
 310 void disable_irq(unsigned int irq)
 311 {
 312         irq_desc_t *desc = irq_desc + irq;
 313         disable_irq_nosync(irq);
 314         if (desc->action)
 315                 synchronize_irq(irq);
 316 }
 317
 318 /**
 319  *      enable_irq - enable interrupt handling on an irq
 320  *      @irq: Interrupt to enable
 321  *
 322  *      Re-enables the processing of interrupts on this IRQ line
 323  *      providing no disable_irq calls are now in effect.
 324  *
 325  *      This function may be called from IRQ context.
 326  */
 327
 328 void enable_irq(unsigned int irq)
 329 {
 330         irq_desc_t *desc = irq_desc + irq;
 331         unsigned long flags;
 332
 333         spin_lock_irqsave(&desc->lock, flags);
 334         switch (desc->depth) {
 335         case 1: {
 336                 unsigned int status = desc->status & ~IRQ_DISABLED;
 337                 desc->status = status;
 338                 if ((status & (IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) {
 339                         desc->status = status | IRQ_REPLAY;
 340                         hw_resend_irq(desc->handler,irq);
 341                 }
 342                 unmask_irq(irq);
 343                 /* fall-through */
 344         }
 345         default:
 346                 desc->depth--;
 347                 break;
 348         case 0:
 349                 printk("enable_irq(%u) unbalanced\n", irq);
 350         }
 351         spin_unlock_irqrestore(&desc->lock, flags);
 352 }
 353
 354 int show_interrupts(struct seq_file *p, void *v)
 355 {
 356         int i = *(loff_t *) v, j;
 357         struct irqaction * action;
 358         unsigned long flags;
 359
 360         if (i == 0) {
 361                 seq_puts(p, "           ");
 362                 for (j=0; j<NR_CPUS; j++)
 363                         if (cpu_online(j))
 364                                 seq_printf(p, "CPU%d       ", j);
 365                 seq_putc(p, '\n');
 366         }
 367
 368         if (i < NR_IRQS) {
 369                 spin_lock_irqsave(&irq_desc[i].lock, flags);
 370                 action = irq_desc[i].action;
 371                 if ( !action || !action->handler )
 372                         goto skip;
 373                 seq_printf(p, "%3d: ", i);
 374 #ifdef CONFIG_SMP
 375                 for (j = 0; j < NR_CPUS; j++)
 376                         if (cpu_online(j))
 377                                 seq_printf(p, "%10u ",
 378                                            kstat_cpu(j).irqs[i]);
 379 #else
 380                 seq_printf(p, "%10u ", kstat_irqs(i));
 381 #endif /* CONFIG_SMP */
 382                 if (irq_desc[i].handler)
 383                         seq_printf(p, " %s ", irq_desc[i].handler->typename);
 384                 else
 385                         seq_puts(p, "  None      ");
 386                 seq_printf(p, "%s", (irq_desc[i].status & IRQ_LEVEL) ? "Level " : "Edge  ");
 387                 seq_printf(p, "    %s", action->name);
 388                 for (action = action->next; action; action = action->next)
 389                         seq_printf(p, ", %s", action->name);
 390                 seq_putc(p, '\n');
 391 skip:
 392                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
 393         } else if (i == NR_IRQS) {
 394 #ifdef CONFIG_TAU_INT
 395                 if (tau_initialized){
 396                         seq_puts(p, "TAU: ");
 397                         for (j = 0; j < NR_CPUS; j++)
 398                                 if (cpu_online(j))
 399                                         seq_printf(p, "%10u ", tau_interrupts(j));
 400                         seq_puts(p, "  PowerPC             Thermal Assist (cpu temp)\n");
 401                 }
 402 #endif
 403 #ifdef CONFIG_SMP
 404                 /* should this be per processor send/receive? */
 405                 seq_printf(p, "IPI (recv/sent): %10u/%u\n",
 406                                 atomic_read(&ipi_recv), atomic_read(&ipi_sent));
 407 #endif
 408                 seq_printf(p, "BAD: %10u\n", ppc_spurious_interrupts);
 409         }
 410         return 0;
 411 }
 412
 413 static inline void
 414 handle_irq_event(int irq, struct pt_regs *regs, struct irqaction *action)
 415 {
 416         int status = 0;
 417
 418         if (!(action->flags & SA_INTERRUPT))
 419                 local_irq_enable();
 420
 421         do {
 422                 status |= action->flags;
 423                 action->handler(irq, action->dev_id, regs);
 424                 action = action->next;
 425         } while (action);
 426         if (status & SA_SAMPLE_RANDOM)
 427                 add_interrupt_randomness(irq);
 428         local_irq_disable();
 429 }
 430
 431 /*
 432  * Eventually, this should take an array of interrupts and an array size
 433  * so it can dispatch multiple interrupts.
 434  */
 435 void ppc_irq_dispatch_handler(struct pt_regs *regs, int irq)
 436 {
 437         int status;
 438         struct irqaction *action;
 439         irq_desc_t *desc = irq_desc + irq;
 440
 441         kstat_this_cpu.irqs[irq]++;
 442         spin_lock(&desc->lock);
 443         ack_irq(irq);
 444         /*
 445            REPLAY is when Linux resends an IRQ that was dropped earlier
 446            WAITING is used by probe to mark irqs that are being tested
 447            */
 448         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 449         if (!(status & IRQ_PER_CPU))
 450                 status |= IRQ_PENDING; /* we _want_ to handle it */
 451
 452         /*
 453          * If the IRQ is disabled for whatever reason, we cannot
 454          * use the action we have.
 455          */
 456         action = NULL;
 457         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
 458                 action = desc->action;
 459                 if (!action || !action->handler) {
 460                         ppc_spurious_interrupts++;
 461                         printk(KERN_DEBUG "Unhandled interrupt %x, disabled\n", irq);
 462                         /* We can't call disable_irq here, it would deadlock */
 463                         ++desc->depth;
 464                         desc->status |= IRQ_DISABLED;
 465                         mask_irq(irq);
 466                         /* This is a real interrupt, we have to eoi it,
 467                            so we jump to out */
 468                         goto out;
 469                 }
 470                 status &= ~IRQ_PENDING; /* we commit to handling */
 471                 if (!(status & IRQ_PER_CPU))
 472                         status |= IRQ_INPROGRESS; /* we are handling it */
 473         }
 474         desc->status = status;
 475
 476         /*
 477          * If there is no IRQ handler or it was disabled, exit early.
 478            Since we set PENDING, if another processor is handling
 479            a different instance of this same irq, the other processor
 480            will take care of it.
 481          */
 482         if (unlikely(!action))
 483                 goto out;
 484
 485
 486         /*
 487          * Edge triggered interrupts need to remember
 488          * pending events.
 489          * This applies to any hw interrupts that allow a second
 490          * instance of the same irq to arrive while we are in do_IRQ
 491          * or in the handler. But the code here only handles the _second_
 492          * instance of the irq, not the third or fourth. So it is mostly
 493          * useful for irq hardware that does not mask cleanly in an
 494          * SMP environment.
 495          */
 496         for (;;) {
 497                 spin_unlock(&desc->lock);
 498                 handle_irq_event(irq, regs, action);
 499                 spin_lock(&desc->lock);
 500
 501                 if (likely(!(desc->status & IRQ_PENDING)))
 502                         break;
 503                 desc->status &= ~IRQ_PENDING;
 504         }
 505 out:
 506         desc->status &= ~IRQ_INPROGRESS;
 507         /*
 508          * The ->end() handler has to deal with interrupts which got
 509          * disabled while the handler was running.
 510          */
 511         if (irq_desc[irq].handler) {
 512                 if (irq_desc[irq].handler->end)
 513                         irq_desc[irq].handler->end(irq);
 514                 else if (irq_desc[irq].handler->enable)
 515                         irq_desc[irq].handler->enable(irq);
 516         }
 517         spin_unlock(&desc->lock);
 518 }
 519
 520 void do_IRQ(struct pt_regs *regs)
 521 {
 522         int irq, first = 1;
 523         irq_enter();
 524
 525         /*
 526          * Every platform is required to implement ppc_md.get_irq.
 527          * This function will either return an irq number or -1 to
 528          * indicate there are no more pending.  But the first time
 529          * through the loop this means there wasn't and IRQ pending.
 530          * The value -2 is for buggy hardware and means that this IRQ
 531          * has already been handled. -- Tom
 532          */
 533         while ((irq = ppc_md.get_irq(regs)) >= 0) {
 534                 ppc_irq_dispatch_handler(regs, irq);
 535                 first = 0;
 536         }
 537         if (irq != -2 && first)
 538                 /* That's not SMP safe ... but who cares ? */
 539                 ppc_spurious_interrupts++;
 540         irq_exit();
 541 }
 542
 543 unsigned long probe_irq_on (void)
 544 {
 545         return 0;
 546 }
 547
 548 EXPORT_SYMBOL(probe_irq_on);
 549
 550 int probe_irq_off (unsigned long irqs)
 551 {
 552         return 0;
 553 }
 554
 555 EXPORT_SYMBOL(probe_irq_off);
 556
 557 unsigned int probe_irq_mask(unsigned long irqs)
 558 {
 559         return 0;
 560 }
 561
 562 #ifdef CONFIG_SMP
 563 void synchronize_irq(unsigned int irq)
 564 {
 565         while (irq_desc[irq].status & IRQ_INPROGRESS)
 566                 barrier();
 567 }
 568 #endif /* CONFIG_SMP */
 569
 570 static struct proc_dir_entry *root_irq_dir;
 571 static struct proc_dir_entry *irq_dir[NR_IRQS];
 572 static struct proc_dir_entry *smp_affinity_entry[NR_IRQS];
 573
 574 #ifdef CONFIG_IRQ_ALL_CPUS
 575 #define DEFAULT_CPU_AFFINITY CPU_MASK_ALL
 576 #else
 577 #define DEFAULT_CPU_AFFINITY cpumask_of_cpu(0)
 578 #endif
 579
 580 cpumask_t irq_affinity [NR_IRQS];
 581
 582 static int irq_affinity_read_proc (char *page, char **start, off_t off,
 583                         int count, int *eof, void *data)
 584 {
 585         int len = cpumask_scnprintf(page, count, irq_affinity[(long)data]);
 586         if (count - len < 2)
 587                 return -EINVAL;
 588         len += sprintf(page + len, "\n");
 589         return len;
 590 }
 591
 592 static int irq_affinity_write_proc (struct file *file, const char __user *buffer,
 593                                         unsigned long count, void *data)
 594 {
 595         int irq = (int) data, full_count = count, err;
 596         cpumask_t new_value, tmp;
 597
 598         if (!irq_desc[irq].handler->set_affinity)
 599                 return -EIO;
 600
 601         err = cpumask_parse(buffer, count, new_value);
 602
 603         /*
 604          * Do not allow disabling IRQs completely - it's a too easy
 605          * way to make the system unusable accidentally :-) At least
 606          * one online CPU still has to be targeted.
 607          *
 608          * We assume a 1-1 logical<->physical cpu mapping here.  If
 609          * we assume that the cpu indices in /proc/irq/../smp_affinity
 610          * are actually logical cpu #'s then we have no problem.
 611          *  -- Cort <cort@fsmlabs.com>
 612          */
 613         cpus_and(tmp, new_value, cpu_online_map);
 614         if (cpus_empty(tmp))
 615                 return -EINVAL;
 616
 617         irq_affinity[irq] = new_value;
 618         irq_desc[irq].handler->set_affinity(irq, new_value);
 619
 620         return full_count;
 621 }
 622
 623 static int prof_cpu_mask_read_proc (char *page, char **start, off_t off,
 624                         int count, int *eof, void *data)
 625 {
 626         int len = cpumask_scnprintf(page, count, *(cpumask_t *)data);
 627         if (count - len < 2)
 628                 return -EINVAL;
 629         len += sprintf(page + len, "\n");
 630         return len;
 631 }
 632
 633 static int prof_cpu_mask_write_proc (struct file *file, const char __user *buffer,
 634                                         unsigned long count, void *data)
 635 {
 636         int err;
 637         int full_count = count;
 638         cpumask_t *mask = (cpumask_t *)data;
 639         cpumask_t new_value;
 640
 641         err = cpumask_parse(buffer, count, new_value);
 642         if (err)
 643                 return err;
 644
 645         *mask = new_value;
 646         return full_count;
 647 }
 648
 649 #define MAX_NAMELEN 10
 650
 651 static void register_irq_proc (unsigned int irq)
 652 {
 653         struct proc_dir_entry *entry;
 654         char name [MAX_NAMELEN];
 655
 656         if (!root_irq_dir || (irq_desc[irq].handler == NULL) || irq_dir[irq])
 657                 return;
 658
 659         memset(name, 0, MAX_NAMELEN);
 660         sprintf(name, "%d", irq);
 661
 662         /* create /proc/irq/1234 */
 663         irq_dir[irq] = proc_mkdir(name, root_irq_dir);
 664
 665         /* create /proc/irq/1234/smp_affinity */
 666         entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);
 667
 668         entry->nlink = 1;
 669         entry->data = (void *)irq;
 670         entry->read_proc = irq_affinity_read_proc;
 671         entry->write_proc = irq_affinity_write_proc;
 672
 673         smp_affinity_entry[irq] = entry;
 674 }
 675
 676 unsigned long prof_cpu_mask = -1;
 677
 678 void init_irq_proc (void)
 679 {
 680         struct proc_dir_entry *entry;
 681         int i;
 682
 683         /* create /proc/irq */
 684         root_irq_dir = proc_mkdir("irq", NULL);
 685
 686         /* create /proc/irq/prof_cpu_mask */
 687         entry = create_proc_entry("prof_cpu_mask", 0600, root_irq_dir);
 688
 689         entry->nlink = 1;
 690         entry->data = (void *)&prof_cpu_mask;
 691         entry->read_proc = prof_cpu_mask_read_proc;
 692         entry->write_proc = prof_cpu_mask_write_proc;
 693
 694         /*
 695          * Create entries for all existing IRQs.
 696          */
 697         for (i = 0; i < NR_IRQS; i++) {
 698                 if (irq_desc[i].handler == NULL)
 699                         continue;
 700                 register_irq_proc(i);
 701         }
 702 }
 703
 704 irqreturn_t no_action(int irq, void *dev, struct pt_regs *regs)
 705 {
 706         return IRQ_NONE;
 707 }
 708
 709 void __init init_IRQ(void)
 710 {
 711         int i;
 712
 713         for (i = 0; i < NR_IRQS; ++i)
 714                 irq_affinity[i] = DEFAULT_CPU_AFFINITY;
 715
 716         ppc_md.init_IRQ();
 717 }