linux/arch/arm/kernel/irq.c
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   1/*
   2 *  linux/arch/arm/kernel/irq.c
   3 *
   4 *  Copyright (C) 1992 Linus Torvalds
   5 *  Modifications for ARM processor Copyright (C) 1995-2000 Russell King.
   6 *
   7 *  Support for Dynamic Tick Timer Copyright (C) 2004-2005 Nokia Corporation.
   8 *  Dynamic Tick Timer written by Tony Lindgren <tony@atomide.com> and
   9 *  Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>.
  10 *
  11 * This program is free software; you can redistribute it and/or modify
  12 * it under the terms of the GNU General Public License version 2 as
  13 * published by the Free Software Foundation.
  14 *
  15 *  This file contains the code used by various IRQ handling routines:
  16 *  asking for different IRQ's should be done through these routines
  17 *  instead of just grabbing them. Thus setups with different IRQ numbers
  18 *  shouldn't result in any weird surprises, and installing new handlers
  19 *  should be easier.
  20 *
  21 *  IRQ's are in fact implemented a bit like signal handlers for the kernel.
  22 *  Naturally it's not a 1:1 relation, but there are similarities.
  23 */
  24#include <linux/kernel_stat.h>
  25#include <linux/module.h>
  26#include <linux/signal.h>
  27#include <linux/ioport.h>
  28#include <linux/interrupt.h>
  29#include <linux/irq.h>
  30#include <linux/ptrace.h>
  31#include <linux/slab.h>
  32#include <linux/random.h>
  33#include <linux/smp.h>
  34#include <linux/init.h>
  35#include <linux/seq_file.h>
  36#include <linux/errno.h>
  37#include <linux/list.h>
  38#include <linux/kallsyms.h>
  39#include <linux/proc_fs.h>
  40
  41#include <asm/system.h>
  42#include <asm/mach/time.h>
  43
  44/*
  45 * No architecture-specific irq_finish function defined in arm/arch/irqs.h.
  46 */
  47#ifndef irq_finish
  48#define irq_finish(irq) do { } while (0)
  49#endif
  50
  51void (*init_arch_irq)(void) __initdata = NULL;
  52unsigned long irq_err_count;
  53
  54int show_interrupts(struct seq_file *p, void *v)
  55{
  56        int i = *(loff_t *) v, cpu;
  57        struct irqaction * action;
  58        unsigned long flags;
  59
  60        if (i == 0) {
  61                char cpuname[12];
  62
  63                seq_printf(p, "    ");
  64                for_each_present_cpu(cpu) {
  65                        sprintf(cpuname, "CPU%d", cpu);
  66                        seq_printf(p, " %10s", cpuname);
  67                }
  68                seq_putc(p, '\n');
  69        }
  70
  71        if (i < NR_IRQS) {
  72                spin_lock_irqsave(&irq_desc[i].lock, flags);
  73                action = irq_desc[i].action;
  74                if (!action)
  75                        goto unlock;
  76
  77                seq_printf(p, "%3d: ", i);
  78                for_each_present_cpu(cpu)
  79                        seq_printf(p, "%10u ", kstat_cpu(cpu).irqs[i]);
  80                seq_printf(p, " %10s", irq_desc[i].chip->name ? : "-");
  81                seq_printf(p, "  %s", action->name);
  82                for (action = action->next; action; action = action->next)
  83                        seq_printf(p, ", %s", action->name);
  84
  85                seq_putc(p, '\n');
  86unlock:
  87                spin_unlock_irqrestore(&irq_desc[i].lock, flags);
  88        } else if (i == NR_IRQS) {
  89#ifdef CONFIG_ARCH_ACORN
  90                show_fiq_list(p, v);
  91#endif
  92#ifdef CONFIG_SMP
  93                show_ipi_list(p);
  94                show_local_irqs(p);
  95#endif
  96                seq_printf(p, "Err: %10lu\n", irq_err_count);
  97        }
  98        return 0;
  99}
 100
 101/* Handle bad interrupts */
 102static struct irq_desc bad_irq_desc = {
 103        .handle_irq = handle_bad_irq,
 104        .lock = SPIN_LOCK_UNLOCKED
 105};
 106
 107/*
 108 * do_IRQ handles all hardware IRQ's.  Decoded IRQs should not
 109 * come via this function.  Instead, they should provide their
 110 * own 'handler'
 111 */
 112asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
 113{
 114        struct pt_regs *old_regs = set_irq_regs(regs);
 115        struct irqdesc *desc = irq_desc + irq;
 116
 117        /*
 118         * Some hardware gives randomly wrong interrupts.  Rather
 119         * than crashing, do something sensible.
 120         */
 121        if (irq >= NR_IRQS)
 122                desc = &bad_irq_desc;
 123
 124        irq_enter();
 125
 126        desc_handle_irq(irq, desc);
 127
 128        /* AT91 specific workaround */
 129        irq_finish(irq);
 130
 131        irq_exit();
 132        set_irq_regs(old_regs);
 133}
 134
 135void set_irq_flags(unsigned int irq, unsigned int iflags)
 136{
 137        struct irqdesc *desc;
 138        unsigned long flags;
 139
 140        if (irq >= NR_IRQS) {
 141                printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
 142                return;
 143        }
 144
 145        desc = irq_desc + irq;
 146        spin_lock_irqsave(&desc->lock, flags);
 147        desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
 148        if (iflags & IRQF_VALID)
 149                desc->status &= ~IRQ_NOREQUEST;
 150        if (iflags & IRQF_PROBE)
 151                desc->status &= ~IRQ_NOPROBE;
 152        if (!(iflags & IRQF_NOAUTOEN))
 153                desc->status &= ~IRQ_NOAUTOEN;
 154        spin_unlock_irqrestore(&desc->lock, flags);
 155}
 156
 157void __init init_IRQ(void)
 158{
 159        int irq;
 160
 161        for (irq = 0; irq < NR_IRQS; irq++)
 162                irq_desc[irq].status |= IRQ_NOREQUEST | IRQ_DELAYED_DISABLE |
 163                        IRQ_NOPROBE;
 164
 165#ifdef CONFIG_SMP
 166        bad_irq_desc.affinity = CPU_MASK_ALL;
 167        bad_irq_desc.cpu = smp_processor_id();
 168#endif
 169        init_arch_irq();
 170}
 171
 172#ifdef CONFIG_HOTPLUG_CPU
 173
 174static void route_irq(struct irqdesc *desc, unsigned int irq, unsigned int cpu)
 175{
 176        pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", irq, desc->cpu, cpu);
 177
 178        spin_lock_irq(&desc->lock);
 179        desc->chip->set_affinity(irq, cpumask_of_cpu(cpu));
 180        spin_unlock_irq(&desc->lock);
 181}
 182
 183/*
 184 * The CPU has been marked offline.  Migrate IRQs off this CPU.  If
 185 * the affinity settings do not allow other CPUs, force them onto any
 186 * available CPU.
 187 */
 188void migrate_irqs(void)
 189{
 190        unsigned int i, cpu = smp_processor_id();
 191
 192        for (i = 0; i < NR_IRQS; i++) {
 193                struct irqdesc *desc = irq_desc + i;
 194
 195                if (desc->cpu == cpu) {
 196                        unsigned int newcpu = any_online_cpu(desc->affinity);
 197
 198                        if (newcpu == NR_CPUS) {
 199                                if (printk_ratelimit())
 200                                        printk(KERN_INFO "IRQ%u no longer affine to CPU%u\n",
 201                                               i, cpu);
 202
 203                                cpus_setall(desc->affinity);
 204                                newcpu = any_online_cpu(desc->affinity);
 205                        }
 206
 207                        route_irq(desc, i, newcpu);
 208                }
 209        }
 210}
 211#endif /* CONFIG_HOTPLUG_CPU */
 212
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