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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/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_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');
  86 unlock:
  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 */
 102 static struct irq_desc bad_irq_desc = {
 103         .handle_irq = handle_bad_irq,
 104         .lock = SPIN_LOCK_UNLOCKED
 105 };
 106
 107 #ifdef CONFIG_CPUMASK_OFFSTACK
 108 /* We are not allocating bad_irq_desc.affinity or .pending_mask */
 109 #error "ARM architecture does not support CONFIG_CPUMASK_OFFSTACK."
 110 #endif
 111
 112 /*
 113  * do_IRQ handles all hardware IRQ's.  Decoded IRQs should not
 114  * come via this function.  Instead, they should provide their
 115  * own 'handler'
 116  */
 117 asmlinkage void __exception asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
 118 {
 119         struct pt_regs *old_regs = set_irq_regs(regs);
 120
 121         irq_enter();
 122
 123         /*
 124          * Some hardware gives randomly wrong interrupts.  Rather
 125          * than crashing, do something sensible.
 126          */
 127         if (irq >= NR_IRQS)
 128                 handle_bad_irq(irq, &bad_irq_desc);
 129         else
 130                 generic_handle_irq(irq);
 131
 132         /* AT91 specific workaround */
 133         irq_finish(irq);
 134
 135         irq_exit();
 136         set_irq_regs(old_regs);
 137 }
 138
 139 void set_irq_flags(unsigned int irq, unsigned int iflags)
 140 {
 141         struct irq_desc *desc;
 142         unsigned long flags;
 143
 144         if (irq >= NR_IRQS) {
 145                 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
 146                 return;
 147         }
 148
 149         desc = irq_desc + irq;
 150         spin_lock_irqsave(&desc->lock, flags);
 151         desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
 152         if (iflags & IRQF_VALID)
 153                 desc->status &= ~IRQ_NOREQUEST;
 154         if (iflags & IRQF_PROBE)
 155                 desc->status &= ~IRQ_NOPROBE;
 156         if (!(iflags & IRQF_NOAUTOEN))
 157                 desc->status &= ~IRQ_NOAUTOEN;
 158         spin_unlock_irqrestore(&desc->lock, flags);
 159 }
 160
 161 void __init init_IRQ(void)
 162 {
 163         int irq;
 164
 165         for (irq = 0; irq < NR_IRQS; irq++)
 166                 irq_desc[irq].status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 167
 168 #ifdef CONFIG_SMP
 169         cpumask_setall(bad_irq_desc.affinity);
 170         bad_irq_desc.cpu = smp_processor_id();
 171 #endif
 172         init_arch_irq();
 173 }
 174
 175 #ifdef CONFIG_HOTPLUG_CPU
 176
 177 static void route_irq(struct irq_desc *desc, unsigned int irq, unsigned int cpu)
 178 {
 179         pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", irq, desc->cpu, cpu);
 180
 181         spin_lock_irq(&desc->lock);
 182         desc->chip->set_affinity(irq, cpumask_of(cpu));
 183         spin_unlock_irq(&desc->lock);
 184 }
 185
 186 /*
 187  * The CPU has been marked offline.  Migrate IRQs off this CPU.  If
 188  * the affinity settings do not allow other CPUs, force them onto any
 189  * available CPU.
 190  */
 191 void migrate_irqs(void)
 192 {
 193         unsigned int i, cpu = smp_processor_id();
 194
 195         for (i = 0; i < NR_IRQS; i++) {
 196                 struct irq_desc *desc = irq_desc + i;
 197
 198                 if (desc->cpu == cpu) {
 199                         unsigned int newcpu = cpumask_any_and(desc->affinity,
 200                                                               cpu_online_mask);
 201                         if (newcpu >= nr_cpu_ids) {
 202                                 if (printk_ratelimit())
 203                                         printk(KERN_INFO "IRQ%u no longer affine to CPU%u\n",
 204                                                i, cpu);
 205
 206                                 cpumask_setall(desc->affinity);
 207                                 newcpu = cpumask_any_and(desc->affinity,
 208                                                          cpu_online_mask);
 209                         }
 210
 211                         route_irq(desc, i, newcpu);
 212                 }
 213         }
 214 }
 215 #endif /* CONFIG_HOTPLUG_CPU */