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/mm.h>
  19 #include <linux/random.h>
  20 #include <linux/sched.h>
  21 #include <linux/seq_file.h>
  22 #include <linux/kallsyms.h>
  23 #include <linux/kgdb.h>
  24 #include <linux/ftrace.h>
  25
  26 #include <asm/atomic.h>
  27 #include <asm/system.h>
  28 #include <asm/uaccess.h>
  29
  30 #ifdef CONFIG_KGDB
  31 int kgdb_early_setup;
  32 #endif
  33
  34 static unsigned long irq_map[NR_IRQS / BITS_PER_LONG];
  35
  36 int allocate_irqno(void)
  37 {
  38         int irq;
  39
  40 again:
  41         irq = find_first_zero_bit(irq_map, NR_IRQS);
  42
  43         if (irq >= NR_IRQS)
  44                 return -ENOSPC;
  45
  46         if (test_and_set_bit(irq, irq_map))
  47                 goto again;
  48
  49         return irq;
  50 }
  51
  52 /*
  53  * Allocate the 16 legacy interrupts for i8259 devices.  This happens early
  54  * in the kernel initialization so treating allocation failure as BUG() is
  55  * ok.
  56  */
  57 void __init alloc_legacy_irqno(void)
  58 {
  59         int i;
  60
  61         for (i = 0; i <= 16; i++)
  62                 BUG_ON(test_and_set_bit(i, irq_map));
  63 }
  64
  65 void free_irqno(unsigned int irq)
  66 {
  67         smp_mb__before_clear_bit();
  68         clear_bit(irq, irq_map);
  69         smp_mb__after_clear_bit();
  70 }
  71
  72 /*
  73  * 'what should we do if we get a hw irq event on an illegal vector'.
  74  * each architecture has to answer this themselves.
  75  */
  76 void ack_bad_irq(unsigned int irq)
  77 {
  78         smtc_im_ack_irq(irq);
  79         printk("unexpected IRQ # %d\n", irq);
  80 }
  81
  82 atomic_t irq_err_count;
  83
  84 /*
  85  * Generic, controller-independent functions:
  86  */
  87
  88 int show_interrupts(struct seq_file *p, void *v)
  89 {
  90         int i = *(loff_t *) v, j;
  91         struct irqaction * action;
  92         unsigned long flags;
  93
  94         if (i == 0) {
  95                 seq_printf(p, "           ");
  96                 for_each_online_cpu(j)
  97                         seq_printf(p, "CPU%d       ", j);
  98                 seq_putc(p, '\n');
  99         }
 100
 101         if (i < NR_IRQS) {
 102                 raw_spin_lock_irqsave(&irq_desc[i].lock, flags);
 103                 action = irq_desc[i].action;
 104                 if (!action)
 105                         goto skip;
 106                 seq_printf(p, "%3d: ", i);
 107 #ifndef CONFIG_SMP
 108                 seq_printf(p, "%10u ", kstat_irqs(i));
 109 #else
 110                 for_each_online_cpu(j)
 111                         seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
 112 #endif
 113                 seq_printf(p, " %14s", irq_desc[i].chip->name);
 114                 seq_printf(p, "  %s", action->name);
 115
 116                 for (action=action->next; action; action = action->next)
 117                         seq_printf(p, ", %s", action->name);
 118
 119                 seq_putc(p, '\n');
 120 skip:
 121                 raw_spin_unlock_irqrestore(&irq_desc[i].lock, flags);
 122         } else if (i == NR_IRQS) {
 123                 seq_putc(p, '\n');
 124                 seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
 125         }
 126         return 0;
 127 }
 128
 129 asmlinkage void spurious_interrupt(void)
 130 {
 131         atomic_inc(&irq_err_count);
 132 }
 133
 134 void __init init_IRQ(void)
 135 {
 136         int i;
 137
 138 #ifdef CONFIG_KGDB
 139         if (kgdb_early_setup)
 140                 return;
 141 #endif
 142
 143         for (i = 0; i < NR_IRQS; i++)
 144                 set_irq_noprobe(i);
 145
 146         arch_init_irq();
 147
 148 #ifdef CONFIG_KGDB
 149         if (!kgdb_early_setup)
 150                 kgdb_early_setup = 1;
 151 #endif
 152 }
 153
 154 #ifdef DEBUG_STACKOVERFLOW
 155 static inline void check_stack_overflow(void)
 156 {
 157         unsigned long sp;
 158
 159         __asm__ __volatile__("move %0, $sp" : "=r" (sp));
 160         sp &= THREAD_MASK;
 161
 162         /*
 163          * Check for stack overflow: is there less than STACK_WARN free?
 164          * STACK_WARN is defined as 1/8 of THREAD_SIZE by default.
 165          */
 166         if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
 167                 printk("do_IRQ: stack overflow: %ld\n",
 168                        sp - sizeof(struct thread_info));
 169                 dump_stack();
 170         }
 171 }
 172 #else
 173 static inline void check_stack_overflow(void) {}
 174 #endif
 175
 176
 177 /*
 178  * do_IRQ handles all normal device IRQ's (the special
 179  * SMP cross-CPU interrupts have their own specific
 180  * handlers).
 181  */
 182 void __irq_entry do_IRQ(unsigned int irq)
 183 {
 184         irq_enter();
 185         check_stack_overflow();
 186         __DO_IRQ_SMTC_HOOK(irq);
 187         generic_handle_irq(irq);
 188         irq_exit();
 189 }
 190
 191 #ifdef CONFIG_MIPS_MT_SMTC_IRQAFF
 192 /*
 193  * To avoid inefficient and in some cases pathological re-checking of
 194  * IRQ affinity, we have this variant that skips the affinity check.
 195  */
 196
 197 void __irq_entry do_IRQ_no_affinity(unsigned int irq)
 198 {
 199         irq_enter();
 200         __NO_AFFINITY_IRQ_SMTC_HOOK(irq);
 201         generic_handle_irq(irq);
 202         irq_exit();
 203 }
 204
 205 #endif /* CONFIG_MIPS_MT_SMTC_IRQAFF */