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
  25 #include <asm/atomic.h>
  26 #include <asm/system.h>
  27 #include <asm/uaccess.h>
  28
  29 static unsigned long irq_map[NR_IRQS / BITS_PER_LONG];
  30
  31 int __devinit allocate_irqno(void)
  32 {
  33         int irq;
  34
  35 again:
  36         irq = find_first_zero_bit(irq_map, NR_IRQS);
  37
  38         if (irq >= NR_IRQS)
  39                 return -ENOSPC;
  40
  41         if (test_and_set_bit(irq, irq_map))
  42                 goto again;
  43
  44         return irq;
  45 }
  46
  47 EXPORT_SYMBOL_GPL(allocate_irqno);
  48
  49 /*
  50  * Allocate the 16 legacy interrupts for i8259 devices.  This happens early
  51  * in the kernel initialization so treating allocation failure as BUG() is
  52  * ok.
  53  */
  54 void __init alloc_legacy_irqno(void)
  55 {
  56         int i;
  57
  58         for (i = 0; i <= 16; i++)
  59                 BUG_ON(test_and_set_bit(i, irq_map));
  60 }
  61
  62 void __devinit free_irqno(unsigned int irq)
  63 {
  64         smp_mb__before_clear_bit();
  65         clear_bit(irq, irq_map);
  66         smp_mb__after_clear_bit();
  67 }
  68
  69 EXPORT_SYMBOL_GPL(free_irqno);
  70
  71 /*
  72  * 'what should we do if we get a hw irq event on an illegal vector'.
  73  * each architecture has to answer this themselves.
  74  */
  75 void ack_bad_irq(unsigned int irq)
  76 {
  77         printk("unexpected IRQ # %d\n", irq);
  78 }
  79
  80 atomic_t irq_err_count;
  81
  82 #ifdef CONFIG_MIPS_MT_SMTC
  83 /*
  84  * SMTC Kernel needs to manipulate low-level CPU interrupt mask
  85  * in do_IRQ. These are passed in setup_irq_smtc() and stored
  86  * in this table.
  87  */
  88 unsigned long irq_hwmask[NR_IRQS];
  89 #endif /* CONFIG_MIPS_MT_SMTC */
  90
  91 /*
  92  * Generic, controller-independent functions:
  93  */
  94
  95 int show_interrupts(struct seq_file *p, void *v)
  96 {
  97         int i = *(loff_t *) v, j;
  98         struct irqaction * action;
  99         unsigned long flags;
 100
 101         if (i == 0) {
 102                 seq_printf(p, "           ");
 103                 for_each_online_cpu(j)
 104                         seq_printf(p, "CPU%d       ",j);
 105                 seq_putc(p, '\n');
 106         }
 107
 108         if (i < NR_IRQS) {
 109                 spin_lock_irqsave(&irq_desc[i].lock, flags);
 110                 action = irq_desc[i].action;
 111                 if (!action)
 112                         goto skip;
 113                 seq_printf(p, "%3d: ",i);
 114 #ifndef CONFIG_SMP
 115                 seq_printf(p, "%10u ", kstat_irqs(i));
 116 #else
 117                 for_each_online_cpu(j)
 118                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
 119 #endif
 120                 seq_printf(p, " %14s", irq_desc[i].chip->name);
 121                 seq_printf(p, "  %s", action->name);
 122
 123                 for (action=action->next; action; action = action->next)
 124                         seq_printf(p, ", %s", action->name);
 125
 126                 seq_putc(p, '\n');
 127 skip:
 128                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
 129         } else if (i == NR_IRQS) {
 130                 seq_putc(p, '\n');
 131                 seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
 132         }
 133         return 0;
 134 }
 135
 136 asmlinkage void spurious_interrupt(void)
 137 {
 138         atomic_inc(&irq_err_count);
 139 }
 140
 141 #ifdef CONFIG_KGDB
 142 extern void breakpoint(void);
 143 extern void set_debug_traps(void);
 144
 145 static int kgdb_flag = 1;
 146 static int __init nokgdb(char *str)
 147 {
 148         kgdb_flag = 0;
 149         return 1;
 150 }
 151 __setup("nokgdb", nokgdb);
 152 #endif
 153
 154 void __init init_IRQ(void)
 155 {
 156         arch_init_irq();
 157
 158 #ifdef CONFIG_KGDB
 159         if (kgdb_flag) {
 160                 printk("Wait for gdb client connection ...\n");
 161                 set_debug_traps();
 162                 breakpoint();
 163         }
 164 #endif
 165 }