/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#include <asm/perftypes.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
 52void (*init_arch_irq)(void) __initdata = NULL;
 53unsigned long irq_err_count;
 54
 55int show_interrupts(struct seq_file *p, void *v)
 56{
 57	int i = *(loff_t *) v, cpu;
 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		raw_spin_lock_irqsave(&irq_desc[i].lock, flags);
 74		action = irq_desc[i].action;
 75		if (!action)
 76			goto unlock;
 77
 78		seq_printf(p, "%3d: ", i);
 79		for_each_present_cpu(cpu)
 80			seq_printf(p, "%10u ", kstat_irqs_cpu(i, cpu));
 81		seq_printf(p, " %10s", irq_desc[i].chip->name ? : "-");
 82		seq_printf(p, "  %s", action->name);
 83		for (action = action->next; action; action = action->next)
 84			seq_printf(p, ", %s", action->name);
 85
 86		seq_putc(p, '\n');
 87unlock:
 88		raw_spin_unlock_irqrestore(&irq_desc[i].lock, flags);
 89	} else if (i == NR_IRQS) {
 90#ifdef CONFIG_FIQ
 91		show_fiq_list(p, v);
 92#endif
 93#ifdef CONFIG_SMP
 94		show_ipi_list(p);
 95		show_local_irqs(p);
 96#endif
 97		seq_printf(p, "Err: %10lu\n", irq_err_count);
 98	}
 99	return 0;
100}
101
102/*
103 * do_IRQ handles all hardware IRQ's.  Decoded IRQs should not
104 * come via this function.  Instead, they should provide their
105 * own 'handler'
106 */
107asmlinkage void __exception asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
108{
109	struct pt_regs *old_regs = set_irq_regs(regs);
110
111	perf_mon_interrupt_in();
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	perf_mon_interrupt_out();
132}
133
134void set_irq_flags(unsigned int irq, unsigned int iflags)
135{
136	struct irq_desc *desc;
137	unsigned long flags;
138
139	if (irq >= NR_IRQS) {
140		printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
141		return;
142	}
143
144	desc = irq_desc + irq;
145	raw_spin_lock_irqsave(&desc->lock, flags);
146	desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
147	if (iflags & IRQF_VALID)
148		desc->status &= ~IRQ_NOREQUEST;
149	if (iflags & IRQF_PROBE)
150		desc->status &= ~IRQ_NOPROBE;
151	if (!(iflags & IRQF_NOAUTOEN))
152		desc->status &= ~IRQ_NOAUTOEN;
153	raw_spin_unlock_irqrestore(&desc->lock, flags);
154}
155
156void __init init_IRQ(void)
157{
158	int irq;
159
160	for (irq = 0; irq < NR_IRQS; irq++)
161		irq_desc[irq].status |= IRQ_NOREQUEST | IRQ_NOPROBE;
162
163	init_arch_irq();
164}
165
166#ifdef CONFIG_HOTPLUG_CPU
167
168static void route_irq(struct irq_desc *desc, unsigned int irq, unsigned int cpu)
169{
170	pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", irq, desc->node, cpu);
171
172	raw_spin_lock_irq(&desc->lock);
173	desc->chip->set_affinity(irq, cpumask_of(cpu));
174	raw_spin_unlock_irq(&desc->lock);
175}
176
177/*
178 * The CPU has been marked offline.  Migrate IRQs off this CPU.  If
179 * the affinity settings do not allow other CPUs, force them onto any
180 * available CPU.
181 */
182void migrate_irqs(void)
183{
184	unsigned int i, cpu = smp_processor_id();
185
186	for (i = 0; i < NR_IRQS; i++) {
187		struct irq_desc *desc = irq_desc + i;
188
189		if (desc->node == cpu) {
190			unsigned int newcpu = cpumask_any_and(desc->affinity,
191							      cpu_online_mask);
192			if (newcpu >= nr_cpu_ids) {
193				if (printk_ratelimit())
194					printk(KERN_INFO "IRQ%u no longer affine to CPU%u\n",
195					       i, cpu);
196
197				cpumask_setall(desc->affinity);
198				newcpu = cpumask_any_and(desc->affinity,
199							 cpu_online_mask);
200			}
201
202			route_irq(desc, i, newcpu);
203		}
204	}
205}
206#endif /* CONFIG_HOTPLUG_CPU */