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Sourcecode: linux-2.6 version File versions

irq.c

/*
 *    linux/arch/alpha/kernel/irq.c
 *
 *    Copyright (C) 1995 Linus Torvalds
 *
 * This file contains the code used by various IRQ handling routines:
 * asking for different IRQ's should be done through these routines
 * instead of just grabbing them. Thus setups with different IRQ numbers
 * shouldn't result in any weird surprises, and installing new handlers
 * should be easier.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel_stat.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/ptrace.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/profile.h>
#include <linux/bitops.h>

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

volatile unsigned long irq_err_count;

void ack_bad_irq(unsigned int irq)
{
      irq_err_count++;
      printk(KERN_CRIT "Unexpected IRQ trap at vector %u\n", irq);
}

#ifdef CONFIG_SMP 
static char irq_user_affinity[NR_IRQS];

int irq_select_affinity(unsigned int irq)
{
      static int last_cpu;
      int cpu = last_cpu + 1;

      if (!irq_desc[irq].chip->set_affinity || irq_user_affinity[irq])
            return 1;

      while (!cpu_possible(cpu) || !cpu_isset(cpu, irq_default_affinity))
            cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
      last_cpu = cpu;

      irq_desc[irq].affinity = cpumask_of_cpu(cpu);
      irq_desc[irq].chip->set_affinity(irq, cpumask_of_cpu(cpu));
      return 0;
}
#endif /* CONFIG_SMP */

int
show_interrupts(struct seq_file *p, void *v)
{
#ifdef CONFIG_SMP
      int j;
#endif
      int irq = *(loff_t *) v;
      struct irqaction * action;
      unsigned long flags;

#ifdef CONFIG_SMP
      if (irq == 0) {
            seq_puts(p, "           ");
            for_each_online_cpu(j)
                  seq_printf(p, "CPU%d       ", j);
            seq_putc(p, '\n');
      }
#endif

      if (irq < ACTUAL_NR_IRQS) {
            spin_lock_irqsave(&irq_desc[irq].lock, flags);
            action = irq_desc[irq].action;
            if (!action) 
                  goto unlock;
            seq_printf(p, "%3d: ", irq);
#ifndef CONFIG_SMP
            seq_printf(p, "%10u ", kstat_irqs(irq));
#else
            for_each_online_cpu(j)
                  seq_printf(p, "%10u ", kstat_cpu(j).irqs[irq]);
#endif
            seq_printf(p, " %14s", irq_desc[irq].chip->typename);
            seq_printf(p, "  %c%s",
                  (action->flags & IRQF_DISABLED)?'+':' ',
                  action->name);

            for (action=action->next; action; action = action->next) {
                  seq_printf(p, ", %c%s",
                          (action->flags & IRQF_DISABLED)?'+':' ',
                           action->name);
            }

            seq_putc(p, '\n');
unlock:
            spin_unlock_irqrestore(&irq_desc[irq].lock, flags);
      } else if (irq == ACTUAL_NR_IRQS) {
#ifdef CONFIG_SMP
            seq_puts(p, "IPI: ");
            for_each_online_cpu(j)
                  seq_printf(p, "%10lu ", cpu_data[j].ipi_count);
            seq_putc(p, '\n');
#endif
            seq_printf(p, "ERR: %10lu\n", irq_err_count);
      }
      return 0;
}

/*
 * handle_irq handles all normal device IRQ's (the special
 * SMP cross-CPU interrupts have their own specific
 * handlers).
 */

#define MAX_ILLEGAL_IRQS 16

void
handle_irq(int irq)
{     
      /* 
       * We ack quickly, we don't want the irq controller
       * thinking we're snobs just because some other CPU has
       * disabled global interrupts (we have already done the
       * INT_ACK cycles, it's too late to try to pretend to the
       * controller that we aren't taking the interrupt).
       *
       * 0 return value means that this irq is already being
       * handled by some other CPU. (or is disabled)
       */
      static unsigned int illegal_count=0;
      
      if ((unsigned) irq > ACTUAL_NR_IRQS && illegal_count < MAX_ILLEGAL_IRQS ) {
            irq_err_count++;
            illegal_count++;
            printk(KERN_CRIT "device_interrupt: invalid interrupt %d\n",
                   irq);
            return;
      }

      irq_enter();
      /*
       * __do_IRQ() must be called with IPL_MAX. Note that we do not
       * explicitly enable interrupts afterwards - some MILO PALcode
       * (namely LX164 one) seems to have severe problems with RTI
       * at IPL 0.
       */
      local_irq_disable();
      __do_IRQ(irq);
      irq_exit();
}

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