Lynx framebuffers multidomain implementation.
[linux/elbrus.git] / arch / arm / kernel / irq.c
blob1e782bdeee490dc69f1b9a43688ae7116f52edbc
1 /*
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
19 * should be easier.
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/signal.h>
26 #include <linux/ioport.h>
27 #include <linux/interrupt.h>
28 #include <linux/irq.h>
29 #include <linux/irqchip.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/export.h>
40 #include <asm/exception.h>
41 #include <asm/mach/arch.h>
42 #include <asm/mach/irq.h>
43 #include <asm/mach/time.h>
45 unsigned long irq_err_count;
47 int arch_show_interrupts(struct seq_file *p, int prec)
49 #ifdef CONFIG_FIQ
50 show_fiq_list(p, prec);
51 #endif
52 #ifdef CONFIG_SMP
53 show_ipi_list(p, prec);
54 #endif
55 seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count);
56 return 0;
60 * handle_IRQ handles all hardware IRQ's. Decoded IRQs should
61 * not come via this function. Instead, they should provide their
62 * own 'handler'. Used by platform code implementing C-based 1st
63 * level decoding.
65 void handle_IRQ(unsigned int irq, struct pt_regs *regs)
67 struct pt_regs *old_regs = set_irq_regs(regs);
69 irq_enter();
72 * Some hardware gives randomly wrong interrupts. Rather
73 * than crashing, do something sensible.
75 if (unlikely(irq >= nr_irqs)) {
76 if (printk_ratelimit())
77 printk(KERN_WARNING "Bad IRQ%u\n", irq);
78 ack_bad_irq(irq);
79 } else {
80 generic_handle_irq(irq);
83 irq_exit();
84 set_irq_regs(old_regs);
88 * asm_do_IRQ is the interface to be used from assembly code.
90 asmlinkage void __exception_irq_entry
91 asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
93 handle_IRQ(irq, regs);
96 void set_irq_flags(unsigned int irq, unsigned int iflags)
98 unsigned long clr = 0, set = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
100 if (irq >= nr_irqs) {
101 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
102 return;
105 if (iflags & IRQF_VALID)
106 clr |= IRQ_NOREQUEST;
107 if (iflags & IRQF_PROBE)
108 clr |= IRQ_NOPROBE;
109 if (!(iflags & IRQF_NOAUTOEN))
110 clr |= IRQ_NOAUTOEN;
111 /* Order is clear bits in "clr" then set bits in "set" */
112 irq_modify_status(irq, clr, set & ~clr);
114 EXPORT_SYMBOL_GPL(set_irq_flags);
116 void __init init_IRQ(void)
118 if (IS_ENABLED(CONFIG_OF) && !machine_desc->init_irq)
119 irqchip_init();
120 else
121 machine_desc->init_irq();
124 #ifdef CONFIG_MULTI_IRQ_HANDLER
125 void __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
127 if (handle_arch_irq)
128 return;
130 handle_arch_irq = handle_irq;
132 #endif
134 #ifdef CONFIG_SPARSE_IRQ
135 int __init arch_probe_nr_irqs(void)
137 nr_irqs = machine_desc->nr_irqs ? machine_desc->nr_irqs : NR_IRQS;
138 return nr_irqs;
140 #endif
142 #ifdef CONFIG_HOTPLUG_CPU
144 static bool migrate_one_irq(struct irq_desc *desc)
146 struct irq_data *d = irq_desc_get_irq_data(desc);
147 const struct cpumask *affinity = d->affinity;
148 struct irq_chip *c;
149 bool ret = false;
152 * If this is a per-CPU interrupt, or the affinity does not
153 * include this CPU, then we have nothing to do.
155 if (irqd_is_per_cpu(d) || !cpumask_test_cpu(smp_processor_id(), affinity))
156 return false;
158 if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
159 affinity = cpu_online_mask;
160 ret = true;
163 c = irq_data_get_irq_chip(d);
164 if (!c->irq_set_affinity)
165 pr_debug("IRQ%u: unable to set affinity\n", d->irq);
166 else if (c->irq_set_affinity(d, affinity, false) == IRQ_SET_MASK_OK && ret)
167 cpumask_copy(d->affinity, affinity);
169 return ret;
173 * The current CPU has been marked offline. Migrate IRQs off this CPU.
174 * If the affinity settings do not allow other CPUs, force them onto any
175 * available CPU.
177 * Note: we must iterate over all IRQs, whether they have an attached
178 * action structure or not, as we need to get chained interrupts too.
180 void migrate_irqs(void)
182 unsigned int i;
183 struct irq_desc *desc;
184 unsigned long flags;
186 local_irq_save(flags);
188 for_each_irq_desc(i, desc) {
189 bool affinity_broken;
191 raw_spin_lock(&desc->lock);
192 affinity_broken = migrate_one_irq(desc);
193 raw_spin_unlock(&desc->lock);
195 if (affinity_broken && printk_ratelimit())
196 pr_warning("IRQ%u no longer affine to CPU%u\n", i,
197 smp_processor_id());
200 local_irq_restore(flags);
202 #endif /* CONFIG_HOTPLUG_CPU */