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 show_interrupts(struct seq_file *p, void *v)
56 int i = *(loff_t *) v, cpu;
57 struct irq_desc *desc;
58 struct irqaction * action;
62 for (prec = 3, n = 1000; prec < 10 && n <= nr_irqs; prec++)
73 seq_printf(p, "%*s ", prec, "");
74 for_each_present_cpu(cpu) {
75 sprintf(cpuname, "CPU%d", cpu);
76 seq_printf(p, " %10s", cpuname);
82 desc = irq_to_desc(i);
83 raw_spin_lock_irqsave(&desc->lock, flags);
84 action = desc->action;
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);
98 raw_spin_unlock_irqrestore(&desc->lock, flags);
99 } else if (i == nr_irqs) {
101 show_fiq_list(p, prec);
104 show_ipi_list(p, prec);
106 #ifdef CONFIG_LOCAL_TIMERS
107 show_local_irqs(p, prec);
109 seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count);
115 * do_IRQ handles all hardware IRQ's. Decoded IRQs should not
116 * come via this function. Instead, they should provide their
119 asmlinkage void __exception_irq_entry
120 asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
122 struct pt_regs *old_regs = set_irq_regs(regs);
127 * Some hardware gives randomly wrong interrupts. Rather
128 * than crashing, do something sensible.
130 if (unlikely(irq >= nr_irqs)) {
131 if (printk_ratelimit())
132 printk(KERN_WARNING "Bad IRQ%u\n", irq);
135 generic_handle_irq(irq);
138 /* AT91 specific workaround */
142 set_irq_regs(old_regs);
145 void set_irq_flags(unsigned int irq, unsigned int iflags)
147 unsigned long clr = 0, set = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
149 if (irq >= nr_irqs) {
150 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
154 if (iflags & IRQF_VALID)
155 clr |= IRQ_NOREQUEST;
156 if (iflags & IRQF_PROBE)
158 if (!(iflags & IRQF_NOAUTOEN))
160 /* Order is clear bits in "clr" then set bits in "set" */
161 irq_modify_status(irq, clr, set & ~clr);
164 void __init init_IRQ(void)
166 machine_desc->init_irq();
169 #ifdef CONFIG_SPARSE_IRQ
170 int __init arch_probe_nr_irqs(void)
172 nr_irqs = machine_desc->nr_irqs ? machine_desc->nr_irqs : NR_IRQS;
177 #ifdef CONFIG_HOTPLUG_CPU
179 static bool migrate_one_irq(struct irq_data *d)
181 unsigned int cpu = cpumask_any_and(d->affinity, cpu_online_mask);
184 if (cpu >= nr_cpu_ids) {
185 cpu = cpumask_any(cpu_online_mask);
189 pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", d->irq, d->node, cpu);
191 d->chip->irq_set_affinity(d, cpumask_of(cpu), true);
197 * The CPU has been marked offline. Migrate IRQs off this CPU. If
198 * the affinity settings do not allow other CPUs, force them onto any
201 void migrate_irqs(void)
203 unsigned int i, cpu = smp_processor_id();
204 struct irq_desc *desc;
207 local_irq_save(flags);
209 for_each_irq_desc(i, desc) {
210 struct irq_data *d = &desc->irq_data;
211 bool affinity_broken = false;
213 raw_spin_lock(&desc->lock);
215 if (desc->action == NULL)
221 affinity_broken = migrate_one_irq(d);
223 raw_spin_unlock(&desc->lock);
225 if (affinity_broken && printk_ratelimit())
226 pr_warning("IRQ%u no longer affine to CPU%u\n", i, cpu);
229 local_irq_restore(flags);
231 #endif /* CONFIG_HOTPLUG_CPU */