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
arch_show_interrupts(struct seq_file * p,int prec)54 int arch_show_interrupts(struct seq_file *p, int prec)
55 {
56 #ifdef CONFIG_FIQ
57 show_fiq_list(p, prec);
58 #endif
59 #ifdef CONFIG_SMP
60 show_ipi_list(p, prec);
61 #endif
62 #ifdef CONFIG_LOCAL_TIMERS
63 show_local_irqs(p, prec);
64 #endif
65 seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count);
66 return 0;
67 }
68
69 /*
70 * do_IRQ handles all hardware IRQ's. Decoded IRQs should not
71 * come via this function. Instead, they should provide their
72 * own 'handler'
73 */
74 asmlinkage void __exception_irq_entry
asm_do_IRQ(unsigned int irq,struct pt_regs * regs)75 asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
76 {
77 struct pt_regs *old_regs = set_irq_regs(regs);
78
79 irq_enter();
80
81 /*
82 * Some hardware gives randomly wrong interrupts. Rather
83 * than crashing, do something sensible.
84 */
85 if (unlikely(irq >= nr_irqs)) {
86 if (printk_ratelimit())
87 printk(KERN_WARNING "Bad IRQ%u\n", irq);
88 ack_bad_irq(irq);
89 } else {
90 generic_handle_irq(irq);
91 }
92
93 /* AT91 specific workaround */
94 irq_finish(irq);
95
96 irq_exit();
97 set_irq_regs(old_regs);
98 }
99
set_irq_flags(unsigned int irq,unsigned int iflags)100 void set_irq_flags(unsigned int irq, unsigned int iflags)
101 {
102 unsigned long clr = 0, set = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
103
104 if (irq >= nr_irqs) {
105 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
106 return;
107 }
108
109 if (iflags & IRQF_VALID)
110 clr |= IRQ_NOREQUEST;
111 if (iflags & IRQF_PROBE)
112 clr |= IRQ_NOPROBE;
113 if (!(iflags & IRQF_NOAUTOEN))
114 clr |= IRQ_NOAUTOEN;
115 /* Order is clear bits in "clr" then set bits in "set" */
116 irq_modify_status(irq, clr, set & ~clr);
117 }
118
init_IRQ(void)119 void __init init_IRQ(void)
120 {
121 machine_desc->init_irq();
122 }
123
124 #ifdef CONFIG_SPARSE_IRQ
arch_probe_nr_irqs(void)125 int __init arch_probe_nr_irqs(void)
126 {
127 nr_irqs = machine_desc->nr_irqs ? machine_desc->nr_irqs : NR_IRQS;
128 return nr_irqs;
129 }
130 #endif
131
132 #ifdef CONFIG_HOTPLUG_CPU
133
migrate_one_irq(struct irq_data * d)134 static bool migrate_one_irq(struct irq_data *d)
135 {
136 unsigned int cpu = cpumask_any_and(d->affinity, cpu_online_mask);
137 bool ret = false;
138
139 if (cpu >= nr_cpu_ids) {
140 cpu = cpumask_any(cpu_online_mask);
141 ret = true;
142 }
143
144 pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", d->irq, d->node, cpu);
145
146 d->chip->irq_set_affinity(d, cpumask_of(cpu), true);
147
148 return ret;
149 }
150
151 /*
152 * The CPU has been marked offline. Migrate IRQs off this CPU. If
153 * the affinity settings do not allow other CPUs, force them onto any
154 * available CPU.
155 */
migrate_irqs(void)156 void migrate_irqs(void)
157 {
158 unsigned int i, cpu = smp_processor_id();
159 struct irq_desc *desc;
160 unsigned long flags;
161
162 local_irq_save(flags);
163
164 for_each_irq_desc(i, desc) {
165 struct irq_data *d = &desc->irq_data;
166 bool affinity_broken = false;
167
168 raw_spin_lock(&desc->lock);
169 do {
170 if (desc->action == NULL)
171 break;
172
173 if (d->node != cpu)
174 break;
175
176 affinity_broken = migrate_one_irq(d);
177 } while (0);
178 raw_spin_unlock(&desc->lock);
179
180 if (affinity_broken && printk_ratelimit())
181 pr_warning("IRQ%u no longer affine to CPU%u\n", i, cpu);
182 }
183
184 local_irq_restore(flags);
185 }
186 #endif /* CONFIG_HOTPLUG_CPU */
187