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git.proxmox.com Git - mirror_ubuntu-zesty-kernel.git/blob - arch/arm/kernel/irq.c
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/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 #include <linux/export.h>
39 #include <asm/exception.h>
40 #include <asm/mach/arch.h>
41 #include <asm/mach/irq.h>
42 #include <asm/mach/time.h>
44 unsigned long irq_err_count
;
46 int arch_show_interrupts(struct seq_file
*p
, int prec
)
49 show_fiq_list(p
, prec
);
52 show_ipi_list(p
, prec
);
54 seq_printf(p
, "%*s: %10lu\n", prec
, "Err", irq_err_count
);
59 * handle_IRQ handles all hardware IRQ's. Decoded IRQs should
60 * not come via this function. Instead, they should provide their
61 * own 'handler'. Used by platform code implementing C-based 1st
64 void handle_IRQ(unsigned int irq
, struct pt_regs
*regs
)
66 struct pt_regs
*old_regs
= set_irq_regs(regs
);
71 * Some hardware gives randomly wrong interrupts. Rather
72 * than crashing, do something sensible.
74 if (unlikely(irq
>= nr_irqs
)) {
75 if (printk_ratelimit())
76 printk(KERN_WARNING
"Bad IRQ%u\n", irq
);
79 generic_handle_irq(irq
);
83 set_irq_regs(old_regs
);
87 * asm_do_IRQ is the interface to be used from assembly code.
89 asmlinkage
void __exception_irq_entry
90 asm_do_IRQ(unsigned int irq
, struct pt_regs
*regs
)
92 handle_IRQ(irq
, regs
);
95 void set_irq_flags(unsigned int irq
, unsigned int iflags
)
97 unsigned long clr
= 0, set
= IRQ_NOREQUEST
| IRQ_NOPROBE
| IRQ_NOAUTOEN
;
100 printk(KERN_ERR
"Trying to set irq flags for IRQ%d\n", irq
);
104 if (iflags
& IRQF_VALID
)
105 clr
|= IRQ_NOREQUEST
;
106 if (iflags
& IRQF_PROBE
)
108 if (!(iflags
& IRQF_NOAUTOEN
))
110 /* Order is clear bits in "clr" then set bits in "set" */
111 irq_modify_status(irq
, clr
, set
& ~clr
);
113 EXPORT_SYMBOL_GPL(set_irq_flags
);
115 void __init
init_IRQ(void)
117 machine_desc
->init_irq();
120 #ifdef CONFIG_SPARSE_IRQ
121 int __init
arch_probe_nr_irqs(void)
123 nr_irqs
= machine_desc
->nr_irqs
? machine_desc
->nr_irqs
: NR_IRQS
;
128 #ifdef CONFIG_HOTPLUG_CPU
130 static bool migrate_one_irq(struct irq_desc
*desc
)
132 struct irq_data
*d
= irq_desc_get_irq_data(desc
);
133 const struct cpumask
*affinity
= d
->affinity
;
138 * If this is a per-CPU interrupt, or the affinity does not
139 * include this CPU, then we have nothing to do.
141 if (irqd_is_per_cpu(d
) || !cpumask_test_cpu(smp_processor_id(), affinity
))
144 if (cpumask_any_and(affinity
, cpu_online_mask
) >= nr_cpu_ids
) {
145 affinity
= cpu_online_mask
;
149 c
= irq_data_get_irq_chip(d
);
150 if (!c
->irq_set_affinity
)
151 pr_debug("IRQ%u: unable to set affinity\n", d
->irq
);
152 else if (c
->irq_set_affinity(d
, affinity
, true) == IRQ_SET_MASK_OK
&& ret
)
153 cpumask_copy(d
->affinity
, affinity
);
159 * The current CPU has been marked offline. Migrate IRQs off this CPU.
160 * If the affinity settings do not allow other CPUs, force them onto any
163 * Note: we must iterate over all IRQs, whether they have an attached
164 * action structure or not, as we need to get chained interrupts too.
166 void migrate_irqs(void)
169 struct irq_desc
*desc
;
172 local_irq_save(flags
);
174 for_each_irq_desc(i
, desc
) {
175 bool affinity_broken
;
177 raw_spin_lock(&desc
->lock
);
178 affinity_broken
= migrate_one_irq(desc
);
179 raw_spin_unlock(&desc
->lock
);
181 if (affinity_broken
&& printk_ratelimit())
182 pr_warning("IRQ%u no longer affine to CPU%u\n", i
,
186 local_irq_restore(flags
);
188 #endif /* CONFIG_HOTPLUG_CPU */