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>
38 #include <linux/ftrace.h>
40 #include <asm/system.h>
41 #include <asm/mach/arch.h>
42 #include <asm/mach/irq.h>
43 #include <asm/mach/time.h>
46 * No architecture-specific irq_finish function defined in arm/arch/irqs.h.
49 #define irq_finish(irq) do { } while (0)
52 unsigned long irq_err_count;
54 int arch_show_interrupts(struct seq_file *p, int prec)
57 show_fiq_list(p, prec);
60 show_ipi_list(p, prec);
62 #ifdef CONFIG_LOCAL_TIMERS
63 show_local_irqs(p, prec);
65 seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count);
70 * do_IRQ handles all hardware IRQ's. Decoded IRQs should not
71 * come via this function. Instead, they should provide their
74 asmlinkage void __exception_irq_entry
75 asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
77 struct pt_regs *old_regs = set_irq_regs(regs);
82 * Some hardware gives randomly wrong interrupts. Rather
83 * than crashing, do something sensible.
85 if (unlikely(irq >= nr_irqs)) {
86 if (printk_ratelimit())
87 printk(KERN_WARNING "Bad IRQ%u\n", irq);
90 generic_handle_irq(irq);
93 /* AT91 specific workaround */
97 set_irq_regs(old_regs);
100 void set_irq_flags(unsigned int irq, unsigned int iflags)
102 unsigned long clr = 0, set = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
104 if (irq >= nr_irqs) {
105 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
109 if (iflags & IRQF_VALID)
110 clr |= IRQ_NOREQUEST;
111 if (iflags & IRQF_PROBE)
113 if (!(iflags & IRQF_NOAUTOEN))
115 /* Order is clear bits in "clr" then set bits in "set" */
116 irq_modify_status(irq, clr, set & ~clr);
119 void __init init_IRQ(void)
121 machine_desc->init_irq();
124 #ifdef CONFIG_SPARSE_IRQ
125 int __init arch_probe_nr_irqs(void)
127 nr_irqs = machine_desc->nr_irqs ? machine_desc->nr_irqs : NR_IRQS;
132 #ifdef CONFIG_HOTPLUG_CPU
134 static bool migrate_one_irq(struct irq_data *d)
136 const struct cpumask *affinity = d->affinity;
139 if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
140 affinity cpu_online_mask;
144 d->chip->irq_set_affinity(d, affinity, true);
150 * The CPU has been marked offline. Migrate IRQs off this CPU. If
151 * the affinity settings do not allow other CPUs, force them onto any
154 void migrate_irqs(void)
156 unsigned int i, cpu = smp_processor_id();
157 struct irq_desc *desc;
160 local_irq_save(flags);
162 for_each_irq_desc(i, desc) {
163 struct irq_data *d = &desc->irq_data;
164 bool affinity_broken = false;
166 raw_spin_lock(&desc->lock);
167 if (desc->action != NULL &&
168 cpumask_test_cpu(smp_processor_id(), d->affinity))
169 affinity_broken = migrate_one_irq(d);
170 raw_spin_unlock(&desc->lock);
172 if (affinity_broken && printk_ratelimit())
173 pr_warning("IRQ%u no longer affine to CPU%u\n", i, cpu);
176 local_irq_restore(flags);
178 #endif /* CONFIG_HOTPLUG_CPU */