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/init.h>
  23 #include <linux/irq.h>
  24 #include <linux/proc_fs.h>
  25 #include <linux/seq_file.h>
  26 #include <linux/profile.h>
  27 #include <linux/bitops.h>
  28
  29 #include <asm/system.h>
  30 #include <asm/io.h>
  31 #include <asm/uaccess.h>
  32
  33 volatile unsigned long irq_err_count;
  34 DEFINE_PER_CPU(unsigned long, irq_pmi_count);
  35
  36 void ack_bad_irq(unsigned int irq)
  37 {
  38         irq_err_count++;
  39         printk(KERN_CRIT "Unexpected IRQ trap at vector %u\n", irq);
  40 }
  41
  42 #ifdef CONFIG_SMP
  43 static char irq_user_affinity[NR_IRQS];
  44
  45 int irq_select_affinity(unsigned int irq)
  46 {
  47         struct irq_data *data = irq_get_irq_data(irq);
  48         struct irq_chip *chip;
  49         static int last_cpu;
  50         int cpu = last_cpu + 1;
  51
  52         if (!data)
  53                 return 1;
  54         chip = irq_data_get_irq_chip(data);
  55
  56         if (!chip->irq_set_affinity || irq_user_affinity[irq])
  57                 return 1;
  58
  59         while (!cpu_possible(cpu) ||
  60                !cpumask_test_cpu(cpu, irq_default_affinity))
  61                 cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
  62         last_cpu = cpu;
  63
  64         cpumask_copy(data->affinity, cpumask_of(cpu));
  65         chip->irq_set_affinity(data, cpumask_of(cpu), false);
  66         return 0;
  67 }
  68 #endif /* CONFIG_SMP */
  69
  70 int arch_show_interrupts(struct seq_file *p, int prec)
  71 {
  72         int j;
  73
  74 #ifdef CONFIG_SMP
  75         seq_puts(p, "IPI: ");
  76         for_each_online_cpu(j)
  77                 seq_printf(p, "%10lu ", cpu_data[j].ipi_count);
  78         seq_putc(p, '\n');
  79 #endif
  80         seq_puts(p, "PMI: ");
  81         for_each_online_cpu(j)
  82                 seq_printf(p, "%10lu ", per_cpu(irq_pmi_count, j));
  83         seq_puts(p, "          Performance Monitoring\n");
  84         seq_printf(p, "ERR: %10lu\n", irq_err_count);
  85         return 0;
  86 }
  87
  88 /*
  89  * handle_irq handles all normal device IRQ's (the special
  90  * SMP cross-CPU interrupts have their own specific
  91  * handlers).
  92  */
  93
  94 #define MAX_ILLEGAL_IRQS 16
  95
  96 void
  97 handle_irq(int irq)
  98 {
  99         /*
 100          * We ack quickly, we don't want the irq controller
 101          * thinking we're snobs just because some other CPU has
 102          * disabled global interrupts (we have already done the
 103          * INT_ACK cycles, it's too late to try to pretend to the
 104          * controller that we aren't taking the interrupt).
 105          *
 106          * 0 return value means that this irq is already being
 107          * handled by some other CPU. (or is disabled)
 108          */
 109         static unsigned int illegal_count=0;
 110         struct irq_desc *desc = irq_to_desc(irq);
 111
 112         if (!desc || ((unsigned) irq > ACTUAL_NR_IRQS &&
 113             illegal_count < MAX_ILLEGAL_IRQS)) {
 114                 irq_err_count++;
 115                 illegal_count++;
 116                 printk(KERN_CRIT "device_interrupt: invalid interrupt %d\n",
 117                        irq);
 118                 return;
 119         }
 120
 121         /*
 122          * From here we must proceed with IPL_MAX. Note that we do not
 123          * explicitly enable interrupts afterwards - some MILO PALcode
 124          * (namely LX164 one) seems to have severe problems with RTI
 125          * at IPL 0.
 126          */
 127         local_irq_disable();
 128         irq_enter();
 129         generic_handle_irq_desc(irq, desc);
 130         irq_exit();
 131 }