1// SPDX-License-Identifier: GPL-2.0-or-later
 2/*
 3 * Copyright (C) 2013 Altera Corporation
 4 * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
 5 * Copyright (C) 2008 Thomas Chou <thomas@wytron.com.tw>
 6 *
 7 * based on irq.c from m68k which is:
 8 *
 9 * Copyright (C) 2007 Greg Ungerer <gerg@snapgear.com>
10 */
11
12#include <linux/init.h>
13#include <linux/interrupt.h>
14#include <linux/of.h>
15
16static u32 ienable;
17
18asmlinkage void do_IRQ(int hwirq, struct pt_regs *regs)
19{
20	struct pt_regs *oldregs = set_irq_regs(regs);
21	int irq;
22
23	irq_enter();
24	irq = irq_find_mapping(NULL, hwirq);
25	generic_handle_irq(irq);
26	irq_exit();
27
28	set_irq_regs(oldregs);
29}
30
31static void chip_unmask(struct irq_data *d)
32{
33	ienable |= (1 << d->hwirq);
34	WRCTL(CTL_IENABLE, ienable);
35}
36
37static void chip_mask(struct irq_data *d)
38{
39	ienable &= ~(1 << d->hwirq);
40	WRCTL(CTL_IENABLE, ienable);
41}
42
43static struct irq_chip m_irq_chip = {
44	.name		= "NIOS2-INTC",
45	.irq_unmask	= chip_unmask,
46	.irq_mask	= chip_mask,
47};
48
49static int irq_map(struct irq_domain *h, unsigned int virq,
50				irq_hw_number_t hw_irq_num)
51{
52	irq_set_chip_and_handler(virq, &m_irq_chip, handle_level_irq);
53
54	return 0;
55}
56
57static const struct irq_domain_ops irq_ops = {
58	.map	= irq_map,
59	.xlate	= irq_domain_xlate_onecell,
60};
61
62void __init init_IRQ(void)
63{
64	struct irq_domain *domain;
65	struct device_node *node;
66
67	node = of_find_compatible_node(NULL, NULL, "altr,nios2-1.0");
68	if (!node)
69		node = of_find_compatible_node(NULL, NULL, "altr,nios2-1.1");
70
71	BUG_ON(!node);
72
73	domain = irq_domain_add_linear(node, NIOS2_CPU_NR_IRQS, &irq_ops, NULL);
74	BUG_ON(!domain);
75
76	irq_set_default_host(domain);
77	of_node_put(node);
78	/* Load the initial ienable value */
79	ienable = RDCTL(CTL_IENABLE);
80}