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