arch/arm/kernel/irq.c

   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/random.h>
  31 #include <linux/smp.h>
  32 #include <linux/init.h>
  33 #include <linux/seq_file.h>
  34 #include <linux/errno.h>
  35 #include <linux/list.h>
  36 #include <linux/kallsyms.h>
  37 #include <linux/proc_fs.h>
  38
  39 #include <asm/system.h>
  40 #include <asm/mach/arch.h>
  41 #include <asm/mach/irq.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
  51 unsigned long irq_err_count;
  52
  53 int show_interrupts(struct seq_file *p, void *v)
  54 {
  55         int i = *(loff_t *) v, cpu;
  56         struct irq_desc *desc;
  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                 desc = irq_to_desc(i);
  73                 raw_spin_lock_irqsave(&desc->lock, flags);
  74                 action = desc->action;
  75                 if (!action)
  76                         goto unlock;
  77
  78                 seq_printf(p, "%3d: ", i);
  79                 for_each_present_cpu(cpu)
  80                         seq_printf(p, "%10u ", kstat_irqs_cpu(i, cpu));
  81                 seq_printf(p, " %10s", desc->chip->name ? : "-");
  82                 seq_printf(p, "  %s", action->name);
  83                 for (action = action->next; action; action = action->next)
  84                         seq_printf(p, ", %s", action->name);
  85
  86                 seq_putc(p, '\n');
  87 unlock:
  88                 raw_spin_unlock_irqrestore(&desc->lock, flags);
  89         } else if (i == nr_irqs) {
  90 #ifdef CONFIG_FIQ
  91                 show_fiq_list(p, v);
  92 #endif
  93 #ifdef CONFIG_SMP
  94                 show_ipi_list(p);
  95                 show_local_irqs(p);
  96 #endif
  97                 seq_printf(p, "Err: %10lu\n", irq_err_count);
  98         }
  99         return 0;
 100 }
 101
 102 /*
 103  * do_IRQ handles all hardware IRQ's.  Decoded IRQs should not
 104  * come via this function.  Instead, they should provide their
 105  * own 'handler'
 106  */
 107 asmlinkage void __exception asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
 108 {
 109         struct pt_regs *old_regs = set_irq_regs(regs);
 110
 111         irq_enter();
 112
 113         /*
 114          * Some hardware gives randomly wrong interrupts.  Rather
 115          * than crashing, do something sensible.
 116          */
 117         if (unlikely(irq >= nr_irqs)) {
 118                 if (printk_ratelimit())
 119                         printk(KERN_WARNING "Bad IRQ%u\n", irq);
 120                 ack_bad_irq(irq);
 121         } else {
 122                 generic_handle_irq(irq);
 123         }
 124
 125         /* AT91 specific workaround */
 126         irq_finish(irq);
 127
 128         irq_exit();
 129         set_irq_regs(old_regs);
 130 }
 131
 132 void set_irq_flags(unsigned int irq, unsigned int iflags)
 133 {
 134         struct irq_desc *desc;
 135         unsigned long flags;
 136
 137         if (irq >= nr_irqs) {
 138                 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
 139                 return;
 140         }
 141
 142         desc = irq_to_desc(irq);
 143         raw_spin_lock_irqsave(&desc->lock, flags);
 144         desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
 145         if (iflags & IRQF_VALID)
 146                 desc->status &= ~IRQ_NOREQUEST;
 147         if (iflags & IRQF_PROBE)
 148                 desc->status &= ~IRQ_NOPROBE;
 149         if (!(iflags & IRQF_NOAUTOEN))
 150                 desc->status &= ~IRQ_NOAUTOEN;
 151         raw_spin_unlock_irqrestore(&desc->lock, flags);
 152 }
 153
 154 void __init init_IRQ(void)
 155 {
 156         machine_desc->init_irq();
 157 }
 158
 159 #ifdef CONFIG_SPARSE_IRQ
 160 int __init arch_probe_nr_irqs(void)
 161 {
 162         nr_irqs = machine_desc->nr_irqs ? machine_desc->nr_irqs : NR_IRQS;
 163         return nr_irqs;
 164 }
 165 #endif
 166
 167 #ifdef CONFIG_HOTPLUG_CPU
 168
 169 static void route_irq(struct irq_desc *desc, unsigned int irq, unsigned int cpu)
 170 {
 171         pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", irq, desc->node, cpu);
 172
 173         raw_spin_lock_irq(&desc->lock);
 174         desc->chip->set_affinity(irq, cpumask_of(cpu));
 175         raw_spin_unlock_irq(&desc->lock);
 176 }
 177
 178 /*
 179  * The CPU has been marked offline.  Migrate IRQs off this CPU.  If
 180  * the affinity settings do not allow other CPUs, force them onto any
 181  * available CPU.
 182  */
 183 void migrate_irqs(void)
 184 {
 185         unsigned int i, cpu = smp_processor_id();
 186         struct irq_desc *desc;
 187
 188         for_each_irq_desc(i, desc) {
 189                 if (desc->node == cpu) {
 190                         unsigned int newcpu = cpumask_any_and(desc->affinity,
 191                                                               cpu_online_mask);
 192                         if (newcpu >= nr_cpu_ids) {
 193                                 if (printk_ratelimit())
 194                                         printk(KERN_INFO "IRQ%u no longer affine to CPU%u\n",
 195                                                i, cpu);
 196
 197                                 cpumask_setall(desc->affinity);
 198                                 newcpu = cpumask_any_and(desc->affinity,
 199                                                          cpu_online_mask);
 200                         }
 201
 202                         route_irq(desc, i, newcpu);
 203                 }
 204         }
 205 }
 206 #endif /* CONFIG_HOTPLUG_CPU */