1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *	DECstation 5000/200 (KN02) Control and Status Register
4 *	interrupts.
5 *
6 *	Copyright (c) 2002, 2003, 2005  Maciej W. Rozycki
7 */
8
9#include <linux/init.h>
10#include <linux/irq.h>
11#include <linux/types.h>
12
13#include <asm/dec/kn02.h>
14
15
16/*
17 * Bits 7:0 of the Control Register are write-only -- the
18 * corresponding bits of the Status Register have a different
19 * meaning.  Hence we use a cache.  It speeds up things a bit
20 * as well.
21 *
22 * There is no default value -- it has to be initialized.
23 */
24u32 cached_kn02_csr;
25
26static int kn02_irq_base;
27
28static void unmask_kn02_irq(struct irq_data *d)
29{
30	volatile u32 *csr = (volatile u32 *)CKSEG1ADDR(KN02_SLOT_BASE +
31						       KN02_CSR);
32
33	cached_kn02_csr |= (1 << (d->irq - kn02_irq_base + 16));
34	*csr = cached_kn02_csr;
35}
36
37static void mask_kn02_irq(struct irq_data *d)
38{
39	volatile u32 *csr = (volatile u32 *)CKSEG1ADDR(KN02_SLOT_BASE +
40						       KN02_CSR);
41
42	cached_kn02_csr &= ~(1 << (d->irq - kn02_irq_base + 16));
43	*csr = cached_kn02_csr;
44}
45
46static void ack_kn02_irq(struct irq_data *d)
47{
48	mask_kn02_irq(d);
49	iob();
50}
51
52static struct irq_chip kn02_irq_type = {
53	.name = "KN02-CSR",
54	.irq_ack = ack_kn02_irq,
55	.irq_mask = mask_kn02_irq,
56	.irq_mask_ack = ack_kn02_irq,
57	.irq_unmask = unmask_kn02_irq,
58};
59
60void __init init_kn02_irqs(int base)
61{
62	volatile u32 *csr = (volatile u32 *)CKSEG1ADDR(KN02_SLOT_BASE +
63						       KN02_CSR);
64	int i;
65
66	/* Mask interrupts. */
67	cached_kn02_csr &= ~KN02_CSR_IOINTEN;
68	*csr = cached_kn02_csr;
69	iob();
70
71	for (i = base; i < base + KN02_IRQ_LINES; i++)
72		irq_set_chip_and_handler(i, &kn02_irq_type, handle_level_irq);
73
74	kn02_irq_base = base;
75}
76