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         static int last_cpu;
  48         int cpu = last_cpu + 1;
  49
  50         if (!irq_desc[irq].chip->set_affinity || irq_user_affinity[irq])
  51                 return 1;
  52
  53         while (!cpu_possible(cpu) ||
  54                !cpumask_test_cpu(cpu, irq_default_affinity))
  55                 cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
  56         last_cpu = cpu;
  57
  58         cpumask_copy(irq_desc[irq].affinity, cpumask_of(cpu));
  59         irq_desc[irq].chip->set_affinity(irq, cpumask_of(cpu));
  60         return 0;
  61 }
  62 #endif /* CONFIG_SMP */
  63
  64 int
  65 show_interrupts(struct seq_file *p, void *v)
  66 {
  67         int j;
  68         int irq = *(loff_t *) v;
  69         struct irqaction * action;
  70         unsigned long flags;
  71
  72 #ifdef CONFIG_SMP
  73         if (irq == 0) {
  74                 seq_puts(p, "           ");
  75                 for_each_online_cpu(j)
  76                         seq_printf(p, "CPU%d       ", j);
  77                 seq_putc(p, '\n');
  78         }
  79 #endif
  80
  81         if (irq < ACTUAL_NR_IRQS) {
  82                 raw_spin_lock_irqsave(&irq_desc[irq].lock, flags);
  83                 action = irq_desc[irq].action;
  84                 if (!action)
  85                         goto unlock;
  86                 seq_printf(p, "%3d: ", irq);
  87 #ifndef CONFIG_SMP
  88                 seq_printf(p, "%10u ", kstat_irqs(irq));
  89 #else
  90                 for_each_online_cpu(j)
  91                         seq_printf(p, "%10u ", kstat_irqs_cpu(irq, j));
  92 #endif
  93                 seq_printf(p, " %14s", irq_desc[irq].chip->name);
  94                 seq_printf(p, "  %c%s",
  95                         (action->flags & IRQF_DISABLED)?'+':' ',
  96                         action->name);
  97
  98                 for (action=action->next; action; action = action->next) {
  99                         seq_printf(p, ", %c%s",
 100                                   (action->flags & IRQF_DISABLED)?'+':' ',
 101                                    action->name);
 102                 }
 103
 104                 seq_putc(p, '\n');
 105 unlock:
 106                 raw_spin_unlock_irqrestore(&irq_desc[irq].lock, flags);
 107         } else if (irq == ACTUAL_NR_IRQS) {
 108 #ifdef CONFIG_SMP
 109                 seq_puts(p, "IPI: ");
 110                 for_each_online_cpu(j)
 111                         seq_printf(p, "%10lu ", cpu_data[j].ipi_count);
 112                 seq_putc(p, '\n');
 113 #endif
 114                 seq_puts(p, "PMI: ");
 115                 for_each_online_cpu(j)
 116                         seq_printf(p, "%10lu ", per_cpu(irq_pmi_count, j));
 117                 seq_puts(p, "          Performance Monitoring\n");
 118                 seq_printf(p, "ERR: %10lu\n", irq_err_count);
 119         }
 120         return 0;
 121 }
 122
 123 /*
 124  * handle_irq handles all normal device IRQ's (the special
 125  * SMP cross-CPU interrupts have their own specific
 126  * handlers).
 127  */
 128
 129 #define MAX_ILLEGAL_IRQS 16
 130
 131 void
 132 handle_irq(int irq)
 133 {
 134         /*
 135          * We ack quickly, we don't want the irq controller
 136          * thinking we're snobs just because some other CPU has
 137          * disabled global interrupts (we have already done the
 138          * INT_ACK cycles, it's too late to try to pretend to the
 139          * controller that we aren't taking the interrupt).
 140          *
 141          * 0 return value means that this irq is already being
 142          * handled by some other CPU. (or is disabled)
 143          */
 144         static unsigned int illegal_count=0;
 145
 146         if ((unsigned) irq > ACTUAL_NR_IRQS && illegal_count < MAX_ILLEGAL_IRQS ) {
 147                 irq_err_count++;
 148                 illegal_count++;
 149                 printk(KERN_CRIT "device_interrupt: invalid interrupt %d\n",
 150                        irq);
 151                 return;
 152         }
 153
 154         irq_enter();
 155         /*
 156          * __do_IRQ() must be called with IPL_MAX. Note that we do not
 157          * explicitly enable interrupts afterwards - some MILO PALcode
 158          * (namely LX164 one) seems to have severe problems with RTI
 159          * at IPL 0.
 160          */
 161         local_irq_disable();
 162         __do_IRQ(irq);
 163         irq_exit();
 164 }