1/*
2 * Copyright (C) 2013 Altera Corporation
3 * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
4 * Copyright (C) 2008 Thomas Chou <thomas@wytron.com.tw>
5 *
6 * based on irq.c from m68k which is:
7 *
8 * Copyright (C) 2007 Greg Ungerer <gerg@snapgear.com>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
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
25#include <linux/init.h>
26#include <linux/interrupt.h>
27#include <linux/of.h>
28
29static u32 ienable;
30
31asmlinkage void do_IRQ(int hwirq, struct pt_regs *regs)
32{
33	struct pt_regs *oldregs = set_irq_regs(regs);
34	int irq;
35
36	irq_enter();
37	irq = irq_find_mapping(NULL, hwirq);
38	generic_handle_irq(irq);
39	irq_exit();
40
41	set_irq_regs(oldregs);
42}
43
44static void chip_unmask(struct irq_data *d)
45{
46	ienable |= (1 << d->hwirq);
47	WRCTL(CTL_IENABLE, ienable);
48}
49
50static void chip_mask(struct irq_data *d)
51{
52	ienable &= ~(1 << d->hwirq);
53	WRCTL(CTL_IENABLE, ienable);
54}
55
56static struct irq_chip m_irq_chip = {
57	.name		= "NIOS2-INTC",
58	.irq_unmask	= chip_unmask,
59	.irq_mask	= chip_mask,
60};
61
62static int irq_map(struct irq_domain *h, unsigned int virq,
63				irq_hw_number_t hw_irq_num)
64{
65	irq_set_chip_and_handler(virq, &m_irq_chip, handle_level_irq);
66
67	return 0;
68}
69
70static struct irq_domain_ops irq_ops = {
71	.map	= irq_map,
72	.xlate	= irq_domain_xlate_onecell,
73};
74
75void __init init_IRQ(void)
76{
77	struct irq_domain *domain;
78	struct device_node *node;
79
80	node = of_find_compatible_node(NULL, NULL, "altr,nios2-1.0");
81	if (!node)
82		node = of_find_compatible_node(NULL, NULL, "altr,nios2-1.1");
83
84	BUG_ON(!node);
85
86	domain = irq_domain_add_linear(node, NIOS2_CPU_NR_IRQS, &irq_ops, NULL);
87	BUG_ON(!domain);
88
89	irq_set_default_host(domain);
90	of_node_put(node);
91	/* Load the initial ienable value */
92	ienable = RDCTL(CTL_IENABLE);
93}
94