arch/mips/kernel/irq.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Code to handle x86 style IRQs plus some generic interrupt stuff.
   7  *
   8  * Copyright (C) 1992 Linus Torvalds
   9  * Copyright (C) 1994 - 2000 Ralf Baechle
  10  */
  11 #include <linux/kernel.h>
  12 #include <linux/delay.h>
  13 #include <linux/init.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/kernel_stat.h>
  16 #include <linux/module.h>
  17 #include <linux/proc_fs.h>
  18 #include <linux/slab.h>
  19 #include <linux/mm.h>
  20 #include <linux/random.h>
  21 #include <linux/sched.h>
  22 #include <linux/seq_file.h>
  23 #include <linux/kallsyms.h>
  24 #include <linux/kgdb.h>
  25 #include <linux/ftrace.h>
  26
  27 #include <asm/atomic.h>
  28 #include <asm/system.h>
  29 #include <asm/uaccess.h>
  30
  31 #ifdef CONFIG_KGDB
  32 int kgdb_early_setup;
  33 #endif
  34
  35 static unsigned long irq_map[NR_IRQS / BITS_PER_LONG];
  36
  37 int allocate_irqno(void)
  38 {
  39         int irq;
  40
  41 again:
  42         irq = find_first_zero_bit(irq_map, NR_IRQS);
  43
  44         if (irq >= NR_IRQS)
  45                 return -ENOSPC;
  46
  47         if (test_and_set_bit(irq, irq_map))
  48                 goto again;
  49
  50         return irq;
  51 }
  52
  53 /*
  54  * Allocate the 16 legacy interrupts for i8259 devices.  This happens early
  55  * in the kernel initialization so treating allocation failure as BUG() is
  56  * ok.
  57  */
  58 void __init alloc_legacy_irqno(void)
  59 {
  60         int i;
  61
  62         for (i = 0; i <= 16; i++)
  63                 BUG_ON(test_and_set_bit(i, irq_map));
  64 }
  65
  66 void free_irqno(unsigned int irq)
  67 {
  68         smp_mb__before_clear_bit();
  69         clear_bit(irq, irq_map);
  70         smp_mb__after_clear_bit();
  71 }
  72
  73 /*
  74  * 'what should we do if we get a hw irq event on an illegal vector'.
  75  * each architecture has to answer this themselves.
  76  */
  77 void ack_bad_irq(unsigned int irq)
  78 {
  79         smtc_im_ack_irq(irq);
  80         printk("unexpected IRQ # %d\n", irq);
  81 }
  82
  83 atomic_t irq_err_count;
  84
  85 /*
  86  * Generic, controller-independent functions:
  87  */
  88
  89 int show_interrupts(struct seq_file *p, void *v)
  90 {
  91         int i = *(loff_t *) v, j;
  92         struct irqaction * action;
  93         unsigned long flags;
  94
  95         if (i == 0) {
  96                 seq_printf(p, "           ");
  97                 for_each_online_cpu(j)
  98                         seq_printf(p, "CPU%d       ", j);
  99                 seq_putc(p, '\n');
 100         }
 101
 102         if (i < NR_IRQS) {
 103                 raw_spin_lock_irqsave(&irq_desc[i].lock, flags);
 104                 action = irq_desc[i].action;
 105                 if (!action)
 106                         goto skip;
 107                 seq_printf(p, "%3d: ", i);
 108 #ifndef CONFIG_SMP
 109                 seq_printf(p, "%10u ", kstat_irqs(i));
 110 #else
 111                 for_each_online_cpu(j)
 112                         seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
 113 #endif
 114                 seq_printf(p, " %14s", irq_desc[i].chip->name);
 115                 seq_printf(p, "  %s", action->name);
 116
 117                 for (action=action->next; action; action = action->next)
 118                         seq_printf(p, ", %s", action->name);
 119
 120                 seq_putc(p, '\n');
 121 skip:
 122                 raw_spin_unlock_irqrestore(&irq_desc[i].lock, flags);
 123         } else if (i == NR_IRQS) {
 124                 seq_putc(p, '\n');
 125                 seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
 126         }
 127         return 0;
 128 }
 129
 130 asmlinkage void spurious_interrupt(void)
 131 {
 132         atomic_inc(&irq_err_count);
 133 }
 134
 135 void __init init_IRQ(void)
 136 {
 137         int i;
 138
 139 #ifdef CONFIG_KGDB
 140         if (kgdb_early_setup)
 141                 return;
 142 #endif
 143
 144         for (i = 0; i < NR_IRQS; i++)
 145                 set_irq_noprobe(i);
 146
 147         arch_init_irq();
 148
 149 #ifdef CONFIG_KGDB
 150         if (!kgdb_early_setup)
 151                 kgdb_early_setup = 1;
 152 #endif
 153 }
 154
 155 /*
 156  * do_IRQ handles all normal device IRQ's (the special
 157  * SMP cross-CPU interrupts have their own specific
 158  * handlers).
 159  */
 160 void __irq_entry do_IRQ(unsigned int irq)
 161 {
 162         irq_enter();
 163         __DO_IRQ_SMTC_HOOK(irq);
 164         generic_handle_irq(irq);
 165         irq_exit();
 166 }
 167
 168 #ifdef CONFIG_MIPS_MT_SMTC_IRQAFF
 169 /*
 170  * To avoid inefficient and in some cases pathological re-checking of
 171  * IRQ affinity, we have this variant that skips the affinity check.
 172  */
 173
 174 void __irq_entry do_IRQ_no_affinity(unsigned int irq)
 175 {
 176         irq_enter();
 177         __NO_AFFINITY_IRQ_SMTC_HOOK(irq);
 178         generic_handle_irq(irq);
 179         irq_exit();
 180 }
 181
 182 #endif /* CONFIG_MIPS_MT_SMTC_IRQAFF */