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/slab.h>
  31 #include <linux/random.h>
  32 #include <linux/smp.h>
  33 #include <linux/init.h>
  34 #include <linux/seq_file.h>
  35 #include <linux/errno.h>
  36 #include <linux/list.h>
  37 #include <linux/kallsyms.h>
  38 #include <linux/proc_fs.h>
  39
  40 #include <asm/system.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 void (*init_arch_irq)(void) __initdata = NULL;
  52 unsigned long irq_err_count;
  53
  54 int 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_irqs_cpu(i, cpu));
  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');
  86 unlock:
  87                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
  88         } else if (i == NR_IRQS) {
  89 #ifdef CONFIG_FIQ
  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 /*
 102  * do_IRQ handles all hardware IRQ's.  Decoded IRQs should not
 103  * come via this function.  Instead, they should provide their
 104  * own 'handler'
 105  */
 106 asmlinkage void __exception asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
 107 {
 108         struct pt_regs *old_regs = set_irq_regs(regs);
 109
 110         irq_enter();
 111
 112         /*
 113          * Some hardware gives randomly wrong interrupts.  Rather
 114          * than crashing, do something sensible.
 115          */
 116         if (unlikely(irq >= NR_IRQS)) {
 117                 if (printk_ratelimit())
 118                         printk(KERN_WARNING "Bad IRQ%u\n", irq);
 119                 ack_bad_irq(irq);
 120         } else {
 121                 generic_handle_irq(irq);
 122         }
 123
 124         /* AT91 specific workaround */
 125         irq_finish(irq);
 126
 127         irq_exit();
 128         set_irq_regs(old_regs);
 129 }
 130
 131 void set_irq_flags(unsigned int irq, unsigned int iflags)
 132 {
 133         struct irq_desc *desc;
 134         unsigned long flags;
 135
 136         if (irq >= NR_IRQS) {
 137                 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
 138                 return;
 139         }
 140
 141         desc = irq_desc + irq;
 142         spin_lock_irqsave(&desc->lock, flags);
 143         desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
 144         if (iflags & IRQF_VALID)
 145                 desc->status &= ~IRQ_NOREQUEST;
 146         if (iflags & IRQF_PROBE)
 147                 desc->status &= ~IRQ_NOPROBE;
 148         if (!(iflags & IRQF_NOAUTOEN))
 149                 desc->status &= ~IRQ_NOAUTOEN;
 150         spin_unlock_irqrestore(&desc->lock, flags);
 151 }
 152
 153 void __init init_IRQ(void)
 154 {
 155         int irq;
 156
 157         for (irq = 0; irq < NR_IRQS; irq++)
 158                 irq_desc[irq].status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 159
 160         init_arch_irq();
 161 }
 162
 163 #ifdef CONFIG_HOTPLUG_CPU
 164
 165 static void route_irq(struct irq_desc *desc, unsigned int irq, unsigned int cpu)
 166 {
 167         pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", irq, desc->node, cpu);
 168
 169         spin_lock_irq(&desc->lock);
 170         desc->chip->set_affinity(irq, cpumask_of(cpu));
 171         spin_unlock_irq(&desc->lock);
 172 }
 173
 174 /*
 175  * The CPU has been marked offline.  Migrate IRQs off this CPU.  If
 176  * the affinity settings do not allow other CPUs, force them onto any
 177  * available CPU.
 178  */
 179 void migrate_irqs(void)
 180 {
 181         unsigned int i, cpu = smp_processor_id();
 182
 183         for (i = 0; i < NR_IRQS; i++) {
 184                 struct irq_desc *desc = irq_desc + i;
 185
 186                 if (desc->node == cpu) {
 187                         unsigned int newcpu = cpumask_any_and(desc->affinity,
 188                                                               cpu_online_mask);
 189                         if (newcpu >= nr_cpu_ids) {
 190                                 if (printk_ratelimit())
 191                                         printk(KERN_INFO "IRQ%u no longer affine to CPU%u\n",
 192                                                i, cpu);
 193
 194                                 cpumask_setall(desc->affinity);
 195                                 newcpu = cpumask_any_and(desc->affinity,
 196                                                          cpu_online_mask);
 197                         }
 198
 199                         route_irq(desc, i, newcpu);
 200                 }
 201         }
 202 }
 203 #endif /* CONFIG_HOTPLUG_CPU */