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
  71 show_interrupts(struct seq_file *p, void *v)
  72 {
  73         int j;
  74         int irq = *(loff_t *) v;
  75         struct irqaction * action;
  76         struct irq_desc *desc;
  77         unsigned long flags;
  78
  79 #ifdef CONFIG_SMP
  80         if (irq == 0) {
  81                 seq_puts(p, "           ");
  82                 for_each_online_cpu(j)
  83                         seq_printf(p, "CPU%d       ", j);
  84                 seq_putc(p, '\n');
  85         }
  86 #endif
  87
  88         if (irq < ACTUAL_NR_IRQS) {
  89                 desc = irq_to_desc(irq);
  90
  91                 if (!desc)
  92                         return 0;
  93
  94                 raw_spin_lock_irqsave(&desc->lock, flags);
  95                 action = desc->action;
  96                 if (!action)
  97                         goto unlock;
  98                 seq_printf(p, "%3d: ", irq);
  99 #ifndef CONFIG_SMP
 100                 seq_printf(p, "%10u ", kstat_irqs(irq));
 101 #else
 102                 for_each_online_cpu(j)
 103                         seq_printf(p, "%10u ", kstat_irqs_cpu(irq, j));
 104 #endif
 105                 seq_printf(p, " %14s", get_irq_desc_chip(desc)->name);
 106                 seq_printf(p, "  %c%s",
 107                         (action->flags & IRQF_DISABLED)?'+':' ',
 108                         action->name);
 109
 110                 for (action=action->next; action; action = action->next) {
 111                         seq_printf(p, ", %c%s",
 112                                   (action->flags & IRQF_DISABLED)?'+':' ',
 113                                    action->name);
 114                 }
 115
 116                 seq_putc(p, '\n');
 117 unlock:
 118                 raw_spin_unlock_irqrestore(&desc->lock, flags);
 119         } else if (irq == ACTUAL_NR_IRQS) {
 120 #ifdef CONFIG_SMP
 121                 seq_puts(p, "IPI: ");
 122                 for_each_online_cpu(j)
 123                         seq_printf(p, "%10lu ", cpu_data[j].ipi_count);
 124                 seq_putc(p, '\n');
 125 #endif
 126                 seq_puts(p, "PMI: ");
 127                 for_each_online_cpu(j)
 128                         seq_printf(p, "%10lu ", per_cpu(irq_pmi_count, j));
 129                 seq_puts(p, "          Performance Monitoring\n");
 130                 seq_printf(p, "ERR: %10lu\n", irq_err_count);
 131         }
 132         return 0;
 133 }
 134
 135 /*
 136  * handle_irq handles all normal device IRQ's (the special
 137  * SMP cross-CPU interrupts have their own specific
 138  * handlers).
 139  */
 140
 141 #define MAX_ILLEGAL_IRQS 16
 142
 143 void
 144 handle_irq(int irq)
 145 {
 146         /*
 147          * We ack quickly, we don't want the irq controller
 148          * thinking we're snobs just because some other CPU has
 149          * disabled global interrupts (we have already done the
 150          * INT_ACK cycles, it's too late to try to pretend to the
 151          * controller that we aren't taking the interrupt).
 152          *
 153          * 0 return value means that this irq is already being
 154          * handled by some other CPU. (or is disabled)
 155          */
 156         static unsigned int illegal_count=0;
 157         struct irq_desc *desc = irq_to_desc(irq);
 158
 159         if (!desc || ((unsigned) irq > ACTUAL_NR_IRQS &&
 160             illegal_count < MAX_ILLEGAL_IRQS)) {
 161                 irq_err_count++;
 162                 illegal_count++;
 163                 printk(KERN_CRIT "device_interrupt: invalid interrupt %d\n",
 164                        irq);
 165                 return;
 166         }
 167
 168         /*
 169          * From here we must proceed with IPL_MAX. Note that we do not
 170          * explicitly enable interrupts afterwards - some MILO PALcode
 171          * (namely LX164 one) seems to have severe problems with RTI
 172          * at IPL 0.
 173          */
 174         local_irq_disable();
 175         irq_enter();
 176         generic_handle_irq_desc(irq, desc);
 177         irq_exit();
 178 }