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irq.c

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Code to handle x86 style IRQs plus some generic interrupt stuff.
 *
 * Copyright (C) 1992 Linus Torvalds
 * Copyright (C) 1994 - 2000 Ralf Baechle
 */
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/random.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/kallsyms.h>
#include <linux/kgdb.h>

#include <asm/atomic.h>
#include <asm/system.h>
#include <asm/uaccess.h>

#ifdef CONFIG_KGDB
int kgdb_early_setup;
#endif

static unsigned long irq_map[NR_IRQS / BITS_PER_LONG];

int allocate_irqno(void)
{
      int irq;

again:
      irq = find_first_zero_bit(irq_map, NR_IRQS);

      if (irq >= NR_IRQS)
            return -ENOSPC;

      if (test_and_set_bit(irq, irq_map))
            goto again;

      return irq;
}

/*
 * Allocate the 16 legacy interrupts for i8259 devices.  This happens early
 * in the kernel initialization so treating allocation failure as BUG() is
 * ok.
 */
void __init alloc_legacy_irqno(void)
{
      int i;

      for (i = 0; i <= 16; i++)
            BUG_ON(test_and_set_bit(i, irq_map));
}

void free_irqno(unsigned int irq)
{
      smp_mb__before_clear_bit();
      clear_bit(irq, irq_map);
      smp_mb__after_clear_bit();
}

/*
 * 'what should we do if we get a hw irq event on an illegal vector'.
 * each architecture has to answer this themselves.
 */
void ack_bad_irq(unsigned int irq)
{
      smtc_im_ack_irq(irq);
      printk("unexpected IRQ # %d\n", irq);
}

atomic_t irq_err_count;

/*
 * Generic, controller-independent functions:
 */

int show_interrupts(struct seq_file *p, void *v)
{
      int i = *(loff_t *) v, j;
      struct irqaction * action;
      unsigned long flags;

      if (i == 0) {
            seq_printf(p, "           ");
            for_each_online_cpu(j)
                  seq_printf(p, "CPU%d       ", j);
            seq_putc(p, '\n');
      }

      if (i < NR_IRQS) {
            spin_lock_irqsave(&irq_desc[i].lock, flags);
            action = irq_desc[i].action;
            if (!action)
                  goto skip;
            seq_printf(p, "%3d: ", i);
#ifndef CONFIG_SMP
            seq_printf(p, "%10u ", kstat_irqs(i));
#else
            for_each_online_cpu(j)
                  seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
#endif
            seq_printf(p, " %14s", irq_desc[i].chip->name);
            seq_printf(p, "  %s", action->name);

            for (action=action->next; action; action = action->next)
                  seq_printf(p, ", %s", action->name);

            seq_putc(p, '\n');
skip:
            spin_unlock_irqrestore(&irq_desc[i].lock, flags);
      } else if (i == NR_IRQS) {
            seq_putc(p, '\n');
            seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
      }
      return 0;
}

asmlinkage void spurious_interrupt(void)
{
      atomic_inc(&irq_err_count);
}

void __init init_IRQ(void)
{
      int i;

#ifdef CONFIG_KGDB
      if (kgdb_early_setup)
            return;
#endif

      for (i = 0; i < NR_IRQS; i++)
            set_irq_noprobe(i);

      arch_init_irq();

#ifdef CONFIG_KGDB
      if (!kgdb_early_setup)
            kgdb_early_setup = 1;
#endif
}

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