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   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/slab.h>
  22 #include <linux/random.h>
  23 #include <linux/init.h>
  24 #include <linux/irq.h>
  25 #include <linux/proc_fs.h>
  26 #include <linux/seq_file.h>
  27 #include <linux/profile.h>
  28 #include <linux/bitops.h>
  29
  30 #include <asm/system.h>
  31 #include <asm/io.h>
  32 #include <asm/uaccess.h>
  33
  34 volatile unsigned long irq_err_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) || !cpu_isset(cpu, irq_default_affinity))
  54                 cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
  55         last_cpu = cpu;
  56
  57         irq_desc[irq].affinity = cpumask_of_cpu(cpu);
  58         irq_desc[irq].chip->set_affinity(irq, cpumask_of_cpu(cpu));
  59         return 0;
  60 }
  61 #endif /* CONFIG_SMP */
  62
  63 int
  64 show_interrupts(struct seq_file *p, void *v)
  65 {
  66 #ifdef CONFIG_SMP
  67         int j;
  68 #endif
  69         int irq = *(loff_t *) v;
  70         struct irqaction * action;
  71         unsigned long flags;
  72
  73 #ifdef CONFIG_SMP
  74         if (irq == 0) {
  75                 seq_puts(p, "           ");
  76                 for_each_online_cpu(j)
  77                         seq_printf(p, "CPU%d       ", j);
  78                 seq_putc(p, '\n');
  79         }
  80 #endif
  81
  82         if (irq < ACTUAL_NR_IRQS) {
  83                 spin_lock_irqsave(&irq_desc[irq].lock, flags);
  84                 action = irq_desc[irq].action;
  85                 if (!action)
  86                         goto unlock;
  87                 seq_printf(p, "%3d: ", irq);
  88 #ifndef CONFIG_SMP
  89                 seq_printf(p, "%10u ", kstat_irqs(irq));
  90 #else
  91                 for_each_online_cpu(j)
  92                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[irq]);
  93 #endif
  94                 seq_printf(p, " %14s", irq_desc[irq].chip->typename);
  95                 seq_printf(p, "  %c%s",
  96                         (action->flags & IRQF_DISABLED)?'+':' ',
  97                         action->name);
  98
  99                 for (action=action->next; action; action = action->next) {
 100                         seq_printf(p, ", %c%s",
 101                                   (action->flags & IRQF_DISABLED)?'+':' ',
 102                                    action->name);
 103                 }
 104
 105                 seq_putc(p, '\n');
 106 unlock:
 107                 spin_unlock_irqrestore(&irq_desc[irq].lock, flags);
 108         } else if (irq == ACTUAL_NR_IRQS) {
 109 #ifdef CONFIG_SMP
 110                 seq_puts(p, "IPI: ");
 111                 for_each_online_cpu(j)
 112                         seq_printf(p, "%10lu ", cpu_data[j].ipi_count);
 113                 seq_putc(p, '\n');
 114 #endif
 115                 seq_printf(p, "ERR: %10lu\n", irq_err_count);
 116         }
 117         return 0;
 118 }
 119
 120 /*
 121  * handle_irq handles all normal device IRQ's (the special
 122  * SMP cross-CPU interrupts have their own specific
 123  * handlers).
 124  */
 125
 126 #define MAX_ILLEGAL_IRQS 16
 127
 128 void
 129 handle_irq(int irq)
 130 {
 131         /*
 132          * We ack quickly, we don't want the irq controller
 133          * thinking we're snobs just because some other CPU has
 134          * disabled global interrupts (we have already done the
 135          * INT_ACK cycles, it's too late to try to pretend to the
 136          * controller that we aren't taking the interrupt).
 137          *
 138          * 0 return value means that this irq is already being
 139          * handled by some other CPU. (or is disabled)
 140          */
 141         static unsigned int illegal_count=0;
 142
 143         if ((unsigned) irq > ACTUAL_NR_IRQS && illegal_count < MAX_ILLEGAL_IRQS ) {
 144                 irq_err_count++;
 145                 illegal_count++;
 146                 printk(KERN_CRIT "device_interrupt: invalid interrupt %d\n",
 147                        irq);
 148                 return;
 149         }
 150
 151         irq_enter();
 152         /*
 153          * __do_IRQ() must be called with IPL_MAX. Note that we do not
 154          * explicitly enable interrupts afterwards - some MILO PALcode
 155          * (namely LX164 one) seems to have severe problems with RTI
 156          * at IPL 0.
 157          */
 158         local_irq_disable();
 159         __do_IRQ(irq);
 160         irq_exit();
 161 }