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 #include <linux/ftrace.h>
  39
  40 #include <asm/system.h>
  41 #include <asm/mach/arch.h>
  42 #include <asm/mach/irq.h>
  43 #include <asm/mach/time.h>
  44
  45 /*
  46  * No architecture-specific irq_finish function defined in arm/arch/irqs.h.
  47  */
  48 #ifndef irq_finish
  49 #define irq_finish(irq) do { } while (0)
  50 #endif
  51
  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         int prec, n;
  61
  62         for (prec = 3, n = 1000; prec < 10 && n <= nr_irqs; prec++)
  63                 n *= 10;
  64
  65 #ifdef CONFIG_SMP
  66         if (prec < 4)
  67                 prec = 4;
  68 #endif
  69
  70         if (i == 0) {
  71                 char cpuname[12];
  72
  73                 seq_printf(p, "%*s ", prec, "");
  74                 for_each_present_cpu(cpu) {
  75                         sprintf(cpuname, "CPU%d", cpu);
  76                         seq_printf(p, " %10s", cpuname);
  77                 }
  78                 seq_putc(p, '\n');
  79         }
  80
  81         if (i < nr_irqs) {
  82                 desc = irq_to_desc(i);
  83                 raw_spin_lock_irqsave(&desc->lock, flags);
  84                 action = desc->action;
  85                 if (!action)
  86                         goto unlock;
  87
  88                 seq_printf(p, "%*d: ", prec, i);
  89                 for_each_present_cpu(cpu)
  90                         seq_printf(p, "%10u ", kstat_irqs_cpu(i, cpu));
  91                 seq_printf(p, " %10s", desc->irq_data.chip->name ? : "-");
  92                 seq_printf(p, "  %s", action->name);
  93                 for (action = action->next; action; action = action->next)
  94                         seq_printf(p, ", %s", action->name);
  95
  96                 seq_putc(p, '\n');
  97 unlock:
  98                 raw_spin_unlock_irqrestore(&desc->lock, flags);
  99         } else if (i == nr_irqs) {
 100 #ifdef CONFIG_FIQ
 101                 show_fiq_list(p, prec);
 102 #endif
 103 #ifdef CONFIG_SMP
 104                 show_ipi_list(p, prec);
 105 #endif
 106 #ifdef CONFIG_LOCAL_TIMERS
 107                 show_local_irqs(p, prec);
 108 #endif
 109                 seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count);
 110         }
 111         return 0;
 112 }
 113
 114 /*
 115  * do_IRQ handles all hardware IRQ's.  Decoded IRQs should not
 116  * come via this function.  Instead, they should provide their
 117  * own 'handler'
 118  */
 119 asmlinkage void __exception_irq_entry
 120 asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
 121 {
 122         struct pt_regs *old_regs = set_irq_regs(regs);
 123
 124         irq_enter();
 125
 126         /*
 127          * Some hardware gives randomly wrong interrupts.  Rather
 128          * than crashing, do something sensible.
 129          */
 130         if (unlikely(irq >= nr_irqs)) {
 131                 if (printk_ratelimit())
 132                         printk(KERN_WARNING "Bad IRQ%u\n", irq);
 133                 ack_bad_irq(irq);
 134         } else {
 135                 generic_handle_irq(irq);
 136         }
 137
 138         /* AT91 specific workaround */
 139         irq_finish(irq);
 140
 141         irq_exit();
 142         set_irq_regs(old_regs);
 143 }
 144
 145 void set_irq_flags(unsigned int irq, unsigned int iflags)
 146 {
 147         struct irq_desc *desc;
 148         unsigned long flags;
 149
 150         if (irq >= nr_irqs) {
 151                 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
 152                 return;
 153         }
 154
 155         desc = irq_to_desc(irq);
 156         raw_spin_lock_irqsave(&desc->lock, flags);
 157         desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
 158         if (iflags & IRQF_VALID)
 159                 desc->status &= ~IRQ_NOREQUEST;
 160         if (iflags & IRQF_PROBE)
 161                 desc->status &= ~IRQ_NOPROBE;
 162         if (!(iflags & IRQF_NOAUTOEN))
 163                 desc->status &= ~IRQ_NOAUTOEN;
 164         raw_spin_unlock_irqrestore(&desc->lock, flags);
 165 }
 166
 167 void __init init_IRQ(void)
 168 {
 169         machine_desc->init_irq();
 170 }
 171
 172 #ifdef CONFIG_SPARSE_IRQ
 173 int __init arch_probe_nr_irqs(void)
 174 {
 175         nr_irqs = machine_desc->nr_irqs ? machine_desc->nr_irqs : NR_IRQS;
 176         return nr_irqs;
 177 }
 178 #endif
 179
 180 #ifdef CONFIG_HOTPLUG_CPU
 181
 182 static bool migrate_one_irq(struct irq_data *d)
 183 {
 184         unsigned int cpu = cpumask_any_and(d->affinity, cpu_online_mask);
 185         bool ret = false;
 186
 187         if (cpu >= nr_cpu_ids) {
 188                 cpu = cpumask_any(cpu_online_mask);
 189                 ret = true;
 190         }
 191
 192         pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", d->irq, d->node, cpu);
 193
 194         d->chip->irq_set_affinity(d, cpumask_of(cpu), true);
 195
 196         return ret;
 197 }
 198
 199 /*
 200  * The CPU has been marked offline.  Migrate IRQs off this CPU.  If
 201  * the affinity settings do not allow other CPUs, force them onto any
 202  * available CPU.
 203  */
 204 void migrate_irqs(void)
 205 {
 206         unsigned int i, cpu = smp_processor_id();
 207         struct irq_desc *desc;
 208         unsigned long flags;
 209
 210         local_irq_save(flags);
 211
 212         for_each_irq_desc(i, desc) {
 213                 struct irq_data *d = &desc->irq_data;
 214                 bool affinity_broken = false;
 215
 216                 raw_spin_lock(&desc->lock);
 217                 do {
 218                         if (desc->action == NULL)
 219                                 break;
 220
 221                         if (d->node != cpu)
 222                                 break;
 223
 224                         affinity_broken = migrate_one_irq(d);
 225                 } while (0);
 226                 raw_spin_unlock(&desc->lock);
 227
 228                 if (affinity_broken && printk_ratelimit())
 229                         pr_warning("IRQ%u no longer affine to CPU%u\n", i, cpu);
 230         }
 231
 232         local_irq_restore(flags);
 233 }
 234 #endif /* CONFIG_HOTPLUG_CPU */