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/signal.h>
26 #include <linux/ioport.h>
27 #include <linux/interrupt.h>
28 #include <linux/irq.h>
29 #include <linux/random.h>
30 #include <linux/smp.h>
31 #include <linux/init.h>
32 #include <linux/seq_file.h>
33 #include <linux/errno.h>
34 #include <linux/list.h>
35 #include <linux/kallsyms.h>
36 #include <linux/proc_fs.h>
37
38 #include <asm/exception.h>
39 #include <asm/mach/arch.h>
40 #include <asm/mach/irq.h>
41 #include <asm/mach/time.h>
42
43 /*
44 * No architecture-specific irq_finish function defined in arm/arch/irqs.h.
45 */
46 #ifndef irq_finish
47 #define irq_finish(irq) do { } while (0)
48 #endif
49
50 unsigned long irq_err_count;
51
arch_show_interrupts(struct seq_file * p,int prec)52 int arch_show_interrupts(struct seq_file *p, int prec)
53 {
54 #ifdef CONFIG_FIQ
55 show_fiq_list(p, prec);
56 #endif
57 #ifdef CONFIG_SMP
58 show_ipi_list(p, prec);
59 #endif
60 seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count);
61 return 0;
62 }
63
64 /*
65 * handle_IRQ handles all hardware IRQ's. Decoded IRQs should
66 * not come via this function. Instead, they should provide their
67 * own 'handler'. Used by platform code implementing C-based 1st
68 * level decoding.
69 */
handle_IRQ(unsigned int irq,struct pt_regs * regs)70 void handle_IRQ(unsigned int irq, struct pt_regs *regs)
71 {
72 struct pt_regs *old_regs = set_irq_regs(regs);
73
74 irq_enter();
75
76 /*
77 * Some hardware gives randomly wrong interrupts. Rather
78 * than crashing, do something sensible.
79 */
80 if (unlikely(irq >= nr_irqs)) {
81 if (printk_ratelimit())
82 printk(KERN_WARNING "Bad IRQ%u\n", irq);
83 ack_bad_irq(irq);
84 } else {
85 generic_handle_irq(irq);
86 }
87
88 /* AT91 specific workaround */
89 irq_finish(irq);
90
91 irq_exit();
92 set_irq_regs(old_regs);
93 }
94
95 /*
96 * asm_do_IRQ is the interface to be used from assembly code.
97 */
98 asmlinkage void __exception_irq_entry
asm_do_IRQ(unsigned int irq,struct pt_regs * regs)99 asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
100 {
101 handle_IRQ(irq, regs);
102 }
103
set_irq_flags(unsigned int irq,unsigned int iflags)104 void set_irq_flags(unsigned int irq, unsigned int iflags)
105 {
106 unsigned long clr = 0, set = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
107
108 if (irq >= nr_irqs) {
109 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
110 return;
111 }
112
113 if (iflags & IRQF_VALID)
114 clr |= IRQ_NOREQUEST;
115 if (iflags & IRQF_PROBE)
116 clr |= IRQ_NOPROBE;
117 if (!(iflags & IRQF_NOAUTOEN))
118 clr |= IRQ_NOAUTOEN;
119 /* Order is clear bits in "clr" then set bits in "set" */
120 irq_modify_status(irq, clr, set & ~clr);
121 }
122
init_IRQ(void)123 void __init init_IRQ(void)
124 {
125 machine_desc->init_irq();
126 }
127
128 #ifdef CONFIG_SPARSE_IRQ
arch_probe_nr_irqs(void)129 int __init arch_probe_nr_irqs(void)
130 {
131 nr_irqs = machine_desc->nr_irqs ? machine_desc->nr_irqs : NR_IRQS;
132 return nr_irqs;
133 }
134 #endif
135
136 #ifdef CONFIG_HOTPLUG_CPU
137
migrate_one_irq(struct irq_desc * desc)138 static bool migrate_one_irq(struct irq_desc *desc)
139 {
140 struct irq_data *d = irq_desc_get_irq_data(desc);
141 const struct cpumask *affinity = d->affinity;
142 struct irq_chip *c;
143 bool ret = false;
144
145 /*
146 * If this is a per-CPU interrupt, or the affinity does not
147 * include this CPU, then we have nothing to do.
148 */
149 if (irqd_is_per_cpu(d) || !cpumask_test_cpu(smp_processor_id(), affinity))
150 return false;
151
152 if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
153 affinity = cpu_online_mask;
154 ret = true;
155 }
156
157 c = irq_data_get_irq_chip(d);
158 if (!c->irq_set_affinity)
159 pr_debug("IRQ%u: unable to set affinity\n", d->irq);
160 else if (c->irq_set_affinity(d, affinity, true) == IRQ_SET_MASK_OK && ret)
161 cpumask_copy(d->affinity, affinity);
162
163 return ret;
164 }
165
166 /*
167 * The current CPU has been marked offline. Migrate IRQs off this CPU.
168 * If the affinity settings do not allow other CPUs, force them onto any
169 * available CPU.
170 *
171 * Note: we must iterate over all IRQs, whether they have an attached
172 * action structure or not, as we need to get chained interrupts too.
173 */
migrate_irqs(void)174 void migrate_irqs(void)
175 {
176 unsigned int i;
177 struct irq_desc *desc;
178 unsigned long flags;
179
180 local_irq_save(flags);
181
182 for_each_irq_desc(i, desc) {
183 bool affinity_broken;
184
185 raw_spin_lock(&desc->lock);
186 affinity_broken = migrate_one_irq(desc);
187 raw_spin_unlock(&desc->lock);
188
189 if (affinity_broken && printk_ratelimit())
190 pr_warning("IRQ%u no longer affine to CPU%u\n", i,
191 smp_processor_id());
192 }
193
194 local_irq_restore(flags);
195 }
196 #endif /* CONFIG_HOTPLUG_CPU */
197