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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/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/irq.h>
  41 #include <asm/mach/time.h>
  42
  43 /*
  44  * No architecture-specific irq_finish function defined in arm/arch/irqs.h.
  45  */
  46 #ifndef irq_finish
  47 #define irq_finish(irq) do { } while (0)
  48 #endif
  49
  50 void (*init_arch_irq)(void) __initdata = NULL;
  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 irqaction * action;
  57         unsigned long flags;
  58
  59         if (i == 0) {
  60                 char cpuname[12];
  61
  62                 seq_printf(p, "    ");
  63                 for_each_present_cpu(cpu) {
  64                         sprintf(cpuname, "CPU%d", cpu);
  65                         seq_printf(p, " %10s", cpuname);
  66                 }
  67                 seq_putc(p, '\n');
  68         }
  69
  70         if (i < NR_IRQS) {
  71                 raw_spin_lock_irqsave(&irq_desc[i].lock, flags);
  72                 action = irq_desc[i].action;
  73                 if (!action)
  74                         goto unlock;
  75
  76                 seq_printf(p, "%3d: ", i);
  77                 for_each_present_cpu(cpu)
  78                         seq_printf(p, "%10u ", kstat_irqs_cpu(i, cpu));
  79                 seq_printf(p, " %10s", irq_desc[i].chip->name ? : "-");
  80                 seq_printf(p, "  %s", action->name);
  81                 for (action = action->next; action; action = action->next)
  82                         seq_printf(p, ", %s", action->name);
  83
  84                 seq_putc(p, '\n');
  85 unlock:
  86                 raw_spin_unlock_irqrestore(&irq_desc[i].lock, flags);
  87         } else if (i == NR_IRQS) {
  88 #ifdef CONFIG_FIQ
  89                 show_fiq_list(p, v);
  90 #endif
  91 #ifdef CONFIG_SMP
  92                 show_ipi_list(p);
  93                 show_local_irqs(p);
  94 #endif
  95                 seq_printf(p, "Err: %10lu\n", irq_err_count);
  96         }
  97         return 0;
  98 }
  99
 100 /*
 101  * do_IRQ handles all hardware IRQ's.  Decoded IRQs should not
 102  * come via this function.  Instead, they should provide their
 103  * own 'handler'
 104  */
 105 asmlinkage void __exception asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
 106 {
 107         struct pt_regs *old_regs = set_irq_regs(regs);
 108
 109         irq_enter();
 110
 111         /*
 112          * Some hardware gives randomly wrong interrupts.  Rather
 113          * than crashing, do something sensible.
 114          */
 115         if (unlikely(irq >= NR_IRQS)) {
 116                 if (printk_ratelimit())
 117                         printk(KERN_WARNING "Bad IRQ%u\n", irq);
 118                 ack_bad_irq(irq);
 119         } else {
 120                 generic_handle_irq(irq);
 121         }
 122
 123         /* AT91 specific workaround */
 124         irq_finish(irq);
 125
 126         irq_exit();
 127         set_irq_regs(old_regs);
 128 }
 129
 130 void set_irq_flags(unsigned int irq, unsigned int iflags)
 131 {
 132         struct irq_desc *desc;
 133         unsigned long flags;
 134
 135         if (irq >= NR_IRQS) {
 136                 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
 137                 return;
 138         }
 139
 140         desc = irq_desc + irq;
 141         raw_spin_lock_irqsave(&desc->lock, flags);
 142         desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
 143         if (iflags & IRQF_VALID)
 144                 desc->status &= ~IRQ_NOREQUEST;
 145         if (iflags & IRQF_PROBE)
 146                 desc->status &= ~IRQ_NOPROBE;
 147         if (!(iflags & IRQF_NOAUTOEN))
 148                 desc->status &= ~IRQ_NOAUTOEN;
 149         raw_spin_unlock_irqrestore(&desc->lock, flags);
 150 }
 151
 152 void __init init_IRQ(void)
 153 {
 154         int irq;
 155
 156         for (irq = 0; irq < NR_IRQS; irq++)
 157                 irq_desc[irq].status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 158
 159         init_arch_irq();
 160 }
 161
 162 #ifdef CONFIG_HOTPLUG_CPU
 163
 164 static void route_irq(struct irq_desc *desc, unsigned int irq, unsigned int cpu)
 165 {
 166         pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", irq, desc->node, cpu);
 167
 168         raw_spin_lock_irq(&desc->lock);
 169         desc->chip->set_affinity(irq, cpumask_of(cpu));
 170         raw_spin_unlock_irq(&desc->lock);
 171 }
 172
 173 /*
 174  * The CPU has been marked offline.  Migrate IRQs off this CPU.  If
 175  * the affinity settings do not allow other CPUs, force them onto any
 176  * available CPU.
 177  */
 178 void migrate_irqs(void)
 179 {
 180         unsigned int i, cpu = smp_processor_id();
 181
 182         for (i = 0; i < NR_IRQS; i++) {
 183                 struct irq_desc *desc = irq_desc + i;
 184
 185                 if (desc->node == cpu) {
 186                         unsigned int newcpu = cpumask_any_and(desc->affinity,
 187                                                               cpu_online_mask);
 188                         if (newcpu >= nr_cpu_ids) {
 189                                 if (printk_ratelimit())
 190                                         printk(KERN_INFO "IRQ%u no longer affine to CPU%u\n",
 191                                                i, cpu);
 192
 193                                 cpumask_setall(desc->affinity);
 194                                 newcpu = cpumask_any_and(desc->affinity,
 195                                                          cpu_online_mask);
 196                         }
 197
 198                         route_irq(desc, i, newcpu);
 199                 }
 200         }
 201 }
 202 #endif /* CONFIG_HOTPLUG_CPU */