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/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 unsigned int arch_nr_irqs;
  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 irq_desc *desc;
  58         struct irqaction * action;
  59         unsigned long flags;
  60
  61         if (i == 0) {
  62                 char cpuname[12];
  63
  64                 seq_printf(p, "    ");
  65                 for_each_present_cpu(cpu) {
  66                         sprintf(cpuname, "CPU%d", cpu);
  67                         seq_printf(p, " %10s", cpuname);
  68                 }
  69                 seq_putc(p, '\n');
  70         }
  71
  72         if (i < nr_irqs) {
  73                 desc = irq_to_desc(i);
  74                 raw_spin_lock_irqsave(&desc->lock, flags);
  75                 action = desc->action;
  76                 if (!action)
  77                         goto unlock;
  78
  79                 seq_printf(p, "%3d: ", i);
  80                 for_each_present_cpu(cpu)
  81                         seq_printf(p, "%10u ", kstat_irqs_cpu(i, cpu));
  82                 seq_printf(p, " %10s", desc->chip->name ? : "-");
  83                 seq_printf(p, "  %s", action->name);
  84                 for (action = action->next; action; action = action->next)
  85                         seq_printf(p, ", %s", action->name);
  86
  87                 seq_putc(p, '\n');
  88 unlock:
  89                 raw_spin_unlock_irqrestore(&desc->lock, flags);
  90         } else if (i == nr_irqs) {
  91 #ifdef CONFIG_FIQ
  92                 show_fiq_list(p, v);
  93 #endif
  94 #ifdef CONFIG_SMP
  95                 show_ipi_list(p);
  96                 show_local_irqs(p);
  97 #endif
  98                 seq_printf(p, "Err: %10lu\n", irq_err_count);
  99         }
 100         return 0;
 101 }
 102
 103 /*
 104  * do_IRQ handles all hardware IRQ's.  Decoded IRQs should not
 105  * come via this function.  Instead, they should provide their
 106  * own 'handler'
 107  */
 108 asmlinkage void __exception asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
 109 {
 110         struct pt_regs *old_regs = set_irq_regs(regs);
 111
 112         irq_enter();
 113
 114         /*
 115          * Some hardware gives randomly wrong interrupts.  Rather
 116          * than crashing, do something sensible.
 117          */
 118         if (unlikely(irq >= nr_irqs)) {
 119                 if (printk_ratelimit())
 120                         printk(KERN_WARNING "Bad IRQ%u\n", irq);
 121                 ack_bad_irq(irq);
 122         } else {
 123                 generic_handle_irq(irq);
 124         }
 125
 126         /* AT91 specific workaround */
 127         irq_finish(irq);
 128
 129         irq_exit();
 130         set_irq_regs(old_regs);
 131 }
 132
 133 void set_irq_flags(unsigned int irq, unsigned int iflags)
 134 {
 135         struct irq_desc *desc;
 136         unsigned long flags;
 137
 138         if (irq >= nr_irqs) {
 139                 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
 140                 return;
 141         }
 142
 143         desc = irq_to_desc(irq);
 144         raw_spin_lock_irqsave(&desc->lock, flags);
 145         desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
 146         if (iflags & IRQF_VALID)
 147                 desc->status &= ~IRQ_NOREQUEST;
 148         if (iflags & IRQF_PROBE)
 149                 desc->status &= ~IRQ_NOPROBE;
 150         if (!(iflags & IRQF_NOAUTOEN))
 151                 desc->status &= ~IRQ_NOAUTOEN;
 152         raw_spin_unlock_irqrestore(&desc->lock, flags);
 153 }
 154
 155 void __init init_IRQ(void)
 156 {
 157         struct irq_desc *desc;
 158         int irq;
 159
 160         for (irq = 0; irq < nr_irqs; irq++) {
 161                 desc = irq_to_desc_alloc_node(irq, 0);
 162                 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 163         }
 164
 165         init_arch_irq();
 166 }
 167
 168 #ifdef CONFIG_SPARSE_IRQ
 169 int __init arch_probe_nr_irqs(void)
 170 {
 171         nr_irqs = arch_nr_irqs ? arch_nr_irqs : NR_IRQS;
 172         return 0;
 173 }
 174 #endif
 175
 176 #ifdef CONFIG_HOTPLUG_CPU
 177
 178 static void route_irq(struct irq_desc *desc, unsigned int irq, unsigned int cpu)
 179 {
 180         pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", irq, desc->node, cpu);
 181
 182         raw_spin_lock_irq(&desc->lock);
 183         desc->chip->set_affinity(irq, cpumask_of(cpu));
 184         raw_spin_unlock_irq(&desc->lock);
 185 }
 186
 187 /*
 188  * The CPU has been marked offline.  Migrate IRQs off this CPU.  If
 189  * the affinity settings do not allow other CPUs, force them onto any
 190  * available CPU.
 191  */
 192 void migrate_irqs(void)
 193 {
 194         unsigned int i, cpu = smp_processor_id();
 195         struct irq_desc *desc;
 196
 197         for_each_irq_desc(i, desc) {
 198                 if (desc->node == 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 */