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 <asm/uaccess.h>
  30
  31 volatile unsigned long irq_err_count;
  32 DEFINE_PER_CPU(unsigned long, irq_pmi_count);
  33
  34 void 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
  41 static char irq_user_affinity[NR_IRQS];
  42
  43 int 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
  68 int 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
  94 void
  95 handle_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 }