2 * linux/arch/arm/kernel/irq.c
4 * Copyright (C) 1992 Linus Torvalds
5 * Modifications for ARM processor Copyright (C) 1995-2000 Russell King.
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>.
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.
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
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.
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>
39 #include <asm/system.h>
40 #include <asm/mach/irq.h>
41 #include <asm/mach/time.h>
44 * No architecture-specific irq_finish function defined in arm/arch/irqs.h.
47 #define irq_finish(irq) do { } while (0)
50 unsigned int arch_nr_irqs;
51 void (*init_arch_irq)(void) __initdata = NULL;
52 unsigned long irq_err_count;
54 int show_interrupts(struct seq_file *p, void *v)
56 int i = *(loff_t *) v, cpu;
57 struct irq_desc *desc;
58 struct irqaction * action;
65 for_each_present_cpu(cpu) {
66 sprintf(cpuname, "CPU%d", cpu);
67 seq_printf(p, " %10s", cpuname);
73 desc = irq_to_desc(i);
74 raw_spin_lock_irqsave(&desc->lock, flags);
75 action = desc->action;
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);
89 raw_spin_unlock_irqrestore(&desc->lock, flags);
90 } else if (i == nr_irqs) {
98 seq_printf(p, "Err: %10lu\n", irq_err_count);
104 * do_IRQ handles all hardware IRQ's. Decoded IRQs should not
105 * come via this function. Instead, they should provide their
108 asmlinkage void __exception asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
110 struct pt_regs *old_regs = set_irq_regs(regs);
115 * Some hardware gives randomly wrong interrupts. Rather
116 * than crashing, do something sensible.
118 if (unlikely(irq >= nr_irqs)) {
119 if (printk_ratelimit())
120 printk(KERN_WARNING "Bad IRQ%u\n", irq);
123 generic_handle_irq(irq);
126 /* AT91 specific workaround */
130 set_irq_regs(old_regs);
133 void set_irq_flags(unsigned int irq, unsigned int iflags)
135 struct irq_desc *desc;
138 if (irq >= nr_irqs) {
139 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
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);
155 void __init init_IRQ(void)
160 #ifdef CONFIG_SPARSE_IRQ
161 int __init arch_probe_nr_irqs(void)
163 nr_irqs = arch_nr_irqs ? arch_nr_irqs : NR_IRQS;
168 #ifdef CONFIG_HOTPLUG_CPU
170 static void route_irq(struct irq_desc *desc, unsigned int irq, unsigned int cpu)
172 pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", irq, desc->node, cpu);
174 raw_spin_lock_irq(&desc->lock);
175 desc->chip->set_affinity(irq, cpumask_of(cpu));
176 raw_spin_unlock_irq(&desc->lock);
180 * The CPU has been marked offline. Migrate IRQs off this CPU. If
181 * the affinity settings do not allow other CPUs, force them onto any
184 void migrate_irqs(void)
186 unsigned int i, cpu = smp_processor_id();
187 struct irq_desc *desc;
189 for_each_irq_desc(i, desc) {
190 if (desc->node == cpu) {
191 unsigned int newcpu = cpumask_any_and(desc->affinity,
193 if (newcpu >= nr_cpu_ids) {
194 if (printk_ratelimit())
195 printk(KERN_INFO "IRQ%u no longer affine to CPU%u\n",
198 cpumask_setall(desc->affinity);
199 newcpu = cpumask_any_and(desc->affinity,
203 route_irq(desc, i, newcpu);
207 #endif /* CONFIG_HOTPLUG_CPU */