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_desc *desc = irq_to_desc[irq];
  48         static int last_cpu;
  49         int cpu = last_cpu + 1;
  50
  51         if (!desc || !get_irq_desc_chip(desc)->set_affinity || irq_user_affinity[irq])
  52                 return 1;
  53
  54         while (!cpu_possible(cpu) ||
  55                !cpumask_test_cpu(cpu, irq_default_affinity))
  56                 cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
  57         last_cpu = cpu;
  58
  59         cpumask_copy(desc->affinity, cpumask_of(cpu));
  60         get_irq_desc_chip(desc)->set_affinity(irq, cpumask_of(cpu));
  61         return 0;
  62 }
  63 #endif /* CONFIG_SMP */
  64
  65 int
  66 show_interrupts(struct seq_file *p, void *v)
  67 {
  68         int j;
  69         int irq = *(loff_t *) v;
  70         struct irqaction * action;
  71         struct irq_desc *desc;
  72         unsigned long flags;
  73
  74 #ifdef CONFIG_SMP
  75         if (irq == 0) {
  76                 seq_puts(p, "           ");
  77                 for_each_online_cpu(j)
  78                         seq_printf(p, "CPU%d       ", j);
  79                 seq_putc(p, '\n');
  80         }
  81 #endif
  82
  83         if (irq < ACTUAL_NR_IRQS) {
  84                 desc = irq_to_desc(irq);
  85
  86                 if (!desc)
  87                         return 0;
  88
  89                 raw_spin_lock_irqsave(&desc->lock, flags);
  90                 action = desc->action;
  91                 if (!action)
  92                         goto unlock;
  93                 seq_printf(p, "%3d: ", irq);
  94 #ifndef CONFIG_SMP
  95                 seq_printf(p, "%10u ", kstat_irqs(irq));
  96 #else
  97                 for_each_online_cpu(j)
  98                         seq_printf(p, "%10u ", kstat_irqs_cpu(irq, j));
  99 #endif
 100                 seq_printf(p, " %14s", get_irq_desc_chip(desc)->name);
 101                 seq_printf(p, "  %c%s",
 102                         (action->flags & IRQF_DISABLED)?'+':' ',
 103                         action->name);
 104
 105                 for (action=action->next; action; action = action->next) {
 106                         seq_printf(p, ", %c%s",
 107                                   (action->flags & IRQF_DISABLED)?'+':' ',
 108                                    action->name);
 109                 }
 110
 111                 seq_putc(p, '\n');
 112 unlock:
 113                 raw_spin_unlock_irqrestore(&desc->lock, flags);
 114         } else if (irq == ACTUAL_NR_IRQS) {
 115 #ifdef CONFIG_SMP
 116                 seq_puts(p, "IPI: ");
 117                 for_each_online_cpu(j)
 118                         seq_printf(p, "%10lu ", cpu_data[j].ipi_count);
 119                 seq_putc(p, '\n');
 120 #endif
 121                 seq_puts(p, "PMI: ");
 122                 for_each_online_cpu(j)
 123                         seq_printf(p, "%10lu ", per_cpu(irq_pmi_count, j));
 124                 seq_puts(p, "          Performance Monitoring\n");
 125                 seq_printf(p, "ERR: %10lu\n", irq_err_count);
 126         }
 127         return 0;
 128 }
 129
 130 /*
 131  * handle_irq handles all normal device IRQ's (the special
 132  * SMP cross-CPU interrupts have their own specific
 133  * handlers).
 134  */
 135
 136 #define MAX_ILLEGAL_IRQS 16
 137
 138 void
 139 handle_irq(int irq)
 140 {
 141         /*
 142          * We ack quickly, we don't want the irq controller
 143          * thinking we're snobs just because some other CPU has
 144          * disabled global interrupts (we have already done the
 145          * INT_ACK cycles, it's too late to try to pretend to the
 146          * controller that we aren't taking the interrupt).
 147          *
 148          * 0 return value means that this irq is already being
 149          * handled by some other CPU. (or is disabled)
 150          */
 151         static unsigned int illegal_count=0;
 152         struct irq_desc *desc = irq_to_desc(irq);
 153
 154         if (!desc || ((unsigned) irq > ACTUAL_NR_IRQS &&
 155             illegal_count < MAX_ILLEGAL_IRQS)) {
 156                 irq_err_count++;
 157                 illegal_count++;
 158                 printk(KERN_CRIT "device_interrupt: invalid interrupt %d\n",
 159                        irq);
 160                 return;
 161         }
 162
 163         /*
 164          * From here we must proceed with IPL_MAX. Note that we do not
 165          * explicitly enable interrupts afterwards - some MILO PALcode
 166          * (namely LX164 one) seems to have severe problems with RTI
 167          * at IPL 0.
 168          */
 169         local_irq_disable();
 170         irq_enter();
 171         generic_handle_irq_desc(irq, desc);
 172         irq_exit();
 173 }