1/*
2 * Based on arch/arm/kernel/irq.c
3 *
4 * Copyright (C) 1992 Linus Torvalds
5 * Modifications for ARM processor Copyright (C) 1995-2000 Russell King.
6 * Support for Dynamic Tick Timer Copyright (C) 2004-2005 Nokia Corporation.
7 * Dynamic Tick Timer written by Tony Lindgren <tony@atomide.com> and
8 * Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>.
9 * Copyright (C) 2012 ARM Ltd.
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 program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
22 */
23
24#include <linux/kernel_stat.h>
25#include <linux/irq.h>
26#include <linux/smp.h>
27#include <linux/init.h>
28#include <linux/irqchip.h>
29#include <linux/seq_file.h>
30#include <linux/ratelimit.h>
31
32unsigned long irq_err_count;
33
34int arch_show_interrupts(struct seq_file *p, int prec)
35{
36#ifdef CONFIG_SMP
37	show_ipi_list(p, prec);
38#endif
39	seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count);
40	return 0;
41}
42
43void (*handle_arch_irq)(struct pt_regs *) = NULL;
44
45void __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
46{
47	if (handle_arch_irq)
48		return;
49
50	handle_arch_irq = handle_irq;
51}
52
53void __init init_IRQ(void)
54{
55	irqchip_init();
56	if (!handle_arch_irq)
57		panic("No interrupt controller found.");
58}
59
60#ifdef CONFIG_HOTPLUG_CPU
61static bool migrate_one_irq(struct irq_desc *desc)
62{
63	struct irq_data *d = irq_desc_get_irq_data(desc);
64	const struct cpumask *affinity = d->affinity;
65	struct irq_chip *c;
66	bool ret = false;
67
68	/*
69	 * If this is a per-CPU interrupt, or the affinity does not
70	 * include this CPU, then we have nothing to do.
71	 */
72	if (irqd_is_per_cpu(d) || !cpumask_test_cpu(smp_processor_id(), affinity))
73		return false;
74
75	if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
76		affinity = cpu_online_mask;
77		ret = true;
78	}
79
80	c = irq_data_get_irq_chip(d);
81	if (!c->irq_set_affinity)
82		pr_debug("IRQ%u: unable to set affinity\n", d->irq);
83	else if (c->irq_set_affinity(d, affinity, false) == IRQ_SET_MASK_OK && ret)
84		cpumask_copy(d->affinity, affinity);
85
86	return ret;
87}
88
89/*
90 * The current CPU has been marked offline.  Migrate IRQs off this CPU.
91 * If the affinity settings do not allow other CPUs, force them onto any
92 * available CPU.
93 *
94 * Note: we must iterate over all IRQs, whether they have an attached
95 * action structure or not, as we need to get chained interrupts too.
96 */
97void migrate_irqs(void)
98{
99	unsigned int i;
100	struct irq_desc *desc;
101	unsigned long flags;
102
103	local_irq_save(flags);
104
105	for_each_irq_desc(i, desc) {
106		bool affinity_broken;
107
108		raw_spin_lock(&desc->lock);
109		affinity_broken = migrate_one_irq(desc);
110		raw_spin_unlock(&desc->lock);
111
112		if (affinity_broken)
113			pr_warn_ratelimited("IRQ%u no longer affine to CPU%u\n",
114					    i, smp_processor_id());
115	}
116
117	local_irq_restore(flags);
118}
119#endif /* CONFIG_HOTPLUG_CPU */
120