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/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
)
50 show_fiq_list(p
, prec
);
53 show_ipi_list(p
, prec
);
55 seq_printf(p
, "%*s: %10lu\n", prec
, "Err", irq_err_count
);
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
65 void handle_IRQ(unsigned int irq
, struct pt_regs
*regs
)
67 struct pt_regs
*old_regs
= set_irq_regs(regs
);
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
);
80 generic_handle_irq(irq
);
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
);
105 if (iflags
& IRQF_VALID
)
106 clr
|= IRQ_NOREQUEST
;
107 if (iflags
& IRQF_PROBE
)
109 if (!(iflags
& IRQF_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
)
121 machine_desc
->init_irq();
124 #ifdef CONFIG_MULTI_IRQ_HANDLER
125 void __init
set_handle_irq(void (*handle_irq
)(struct pt_regs
*))
130 handle_arch_irq
= handle_irq
;
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
;
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
;
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
))
158 if (cpumask_any_and(affinity
, cpu_online_mask
) >= nr_cpu_ids
) {
159 affinity
= cpu_online_mask
;
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
);
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
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)
183 struct irq_desc
*desc
;
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
,
200 local_irq_restore(flags
);
202 #endif /* CONFIG_HOTPLUG_CPU */