LXR linux/arch/alpha/kernel/irq.c

   1/*
   2 *      linux/arch/alpha/kernel/irq.c
   3 *
   4 *      Copyright (C) 1995 Linus Torvalds
   5 *
   6 * This file contains the code used by various IRQ handling routines:
   7 * asking for different IRQ's should be done through these routines
   8 * instead of just grabbing them. Thus setups with different IRQ numbers
   9 * shouldn't result in any weird surprises, and installing new handlers
  10 * should be easier.
  11 */
  12
  13#include <linux/kernel.h>
  14#include <linux/module.h>
  15#include <linux/errno.h>
  16#include <linux/kernel_stat.h>
  17#include <linux/signal.h>
  18#include <linux/sched.h>
  19#include <linux/ptrace.h>
  20#include <linux/interrupt.h>
  21#include <linux/random.h>
  22#include <linux/irq.h>
  23#include <linux/proc_fs.h>
  24#include <linux/seq_file.h>
  25#include <linux/profile.h>
  26#include <linux/bitops.h>
  27
  28#include <asm/io.h>
  29#include <linux/uaccess.h>
  30
  31volatile unsigned long irq_err_count;
  32DEFINE_PER_CPU(unsigned long, irq_pmi_count);
  33
  34void ack_bad_irq(unsigned int irq)
  35{
  36        irq_err_count++;
  37        printk(KERN_CRIT "Unexpected IRQ trap at vector %u\n", irq);
  38}
  39
  40#ifdef CONFIG_SMP 
  41static char irq_user_affinity[NR_IRQS];
  42
  43int irq_select_affinity(unsigned int irq)
  44{
  45        struct irq_data *data = irq_get_irq_data(irq);
  46        struct irq_chip *chip;
  47        static int last_cpu;
  48        int cpu = last_cpu + 1;
  49
  50        if (!data)
  51                return 1;
  52        chip = irq_data_get_irq_chip(data);
  53
  54        if (!chip->irq_set_affinity || irq_user_affinity[irq])
  55                return 1;
  56
  57        while (!cpu_possible(cpu) ||
  58               !cpumask_test_cpu(cpu, irq_default_affinity))
  59                cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
  60        last_cpu = cpu;
  61
  62        cpumask_copy(irq_data_get_affinity_mask(data), cpumask_of(cpu));
  63        chip->irq_set_affinity(data, cpumask_of(cpu), false);
  64        return 0;
  65}
  66#endif /* CONFIG_SMP */
  67
  68int arch_show_interrupts(struct seq_file *p, int prec)
  69{
  70        int j;
  71
  72#ifdef CONFIG_SMP
  73        seq_puts(p, "IPI: ");
  74        for_each_online_cpu(j)
  75                seq_printf(p, "%10lu ", cpu_data[j].ipi_count);
  76        seq_putc(p, '\n');
  77#endif
  78        seq_puts(p, "PMI: ");
  79        for_each_online_cpu(j)
  80                seq_printf(p, "%10lu ", per_cpu(irq_pmi_count, j));
  81        seq_puts(p, "          Performance Monitoring\n");
  82        seq_printf(p, "ERR: %10lu\n", irq_err_count);
  83        return 0;
  84}
  85
  86/*
  87 * handle_irq handles all normal device IRQ's (the special
  88 * SMP cross-CPU interrupts have their own specific
  89 * handlers).
  90 */
  91
  92#define MAX_ILLEGAL_IRQS 16
  93
  94void
  95handle_irq(int irq)
  96{       
  97        /* 
  98         * We ack quickly, we don't want the irq controller
  99         * thinking we're snobs just because some other CPU has
 100         * disabled global interrupts (we have already done the
 101         * INT_ACK cycles, it's too late to try to pretend to the
 102         * controller that we aren't taking the interrupt).
 103         *
 104         * 0 return value means that this irq is already being
 105         * handled by some other CPU. (or is disabled)
 106         */
 107        static unsigned int illegal_count=0;
 108        struct irq_desc *desc = irq_to_desc(irq);
 109        
 110        if (!desc || ((unsigned) irq > ACTUAL_NR_IRQS &&
 111            illegal_count < MAX_ILLEGAL_IRQS)) {
 112                irq_err_count++;
 113                illegal_count++;
 114                printk(KERN_CRIT "device_interrupt: invalid interrupt %d\n",
 115                       irq);
 116                return;
 117        }
 118
 119        irq_enter();
 120        generic_handle_irq_desc(desc);
 121        irq_exit();
 122}
 123