1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/arch/arm/mach-footbridge/irq.c
4 *
5 * Copyright (C) 1996-2000 Russell King
6 *
7 * Changelog:
8 * 22-Aug-1998 RMK Restructured IRQ routines
9 * 03-Sep-1998 PJB Merged CATS support
10 * 20-Jan-1998 RMK Started merge of EBSA286, CATS and NetWinder
11 * 26-Jan-1999 PJB Don't use IACK on CATS
12 * 16-Mar-1999 RMK Added autodetect of ISA PICs
13 */
14#include <linux/ioport.h>
15#include <linux/interrupt.h>
16#include <linux/list.h>
17#include <linux/init.h>
18#include <linux/io.h>
19#include <linux/spinlock.h>
20
21#include <asm/mach/irq.h>
22
23#include <mach/hardware.h>
24#include <asm/hardware/dec21285.h>
25#include <asm/irq.h>
26#include <asm/mach-types.h>
27
28#include "common.h"
29
30static void isa_mask_pic_lo_irq(struct irq_data *d)
31{
32 unsigned int mask = 1 << (d->irq & 7);
33
34 outb(inb(port: PIC_MASK_LO) | mask, port: PIC_MASK_LO);
35}
36
37static void isa_ack_pic_lo_irq(struct irq_data *d)
38{
39 unsigned int mask = 1 << (d->irq & 7);
40
41 outb(inb(port: PIC_MASK_LO) | mask, port: PIC_MASK_LO);
42 outb(value: 0x20, port: PIC_LO);
43}
44
45static void isa_unmask_pic_lo_irq(struct irq_data *d)
46{
47 unsigned int mask = 1 << (d->irq & 7);
48
49 outb(inb(port: PIC_MASK_LO) & ~mask, port: PIC_MASK_LO);
50}
51
52static struct irq_chip isa_lo_chip = {
53 .irq_ack = isa_ack_pic_lo_irq,
54 .irq_mask = isa_mask_pic_lo_irq,
55 .irq_unmask = isa_unmask_pic_lo_irq,
56};
57
58static void isa_mask_pic_hi_irq(struct irq_data *d)
59{
60 unsigned int mask = 1 << (d->irq & 7);
61
62 outb(inb(port: PIC_MASK_HI) | mask, port: PIC_MASK_HI);
63}
64
65static void isa_ack_pic_hi_irq(struct irq_data *d)
66{
67 unsigned int mask = 1 << (d->irq & 7);
68
69 outb(inb(port: PIC_MASK_HI) | mask, port: PIC_MASK_HI);
70 outb(value: 0x62, port: PIC_LO);
71 outb(value: 0x20, port: PIC_HI);
72}
73
74static void isa_unmask_pic_hi_irq(struct irq_data *d)
75{
76 unsigned int mask = 1 << (d->irq & 7);
77
78 outb(inb(port: PIC_MASK_HI) & ~mask, port: PIC_MASK_HI);
79}
80
81static struct irq_chip isa_hi_chip = {
82 .irq_ack = isa_ack_pic_hi_irq,
83 .irq_mask = isa_mask_pic_hi_irq,
84 .irq_unmask = isa_unmask_pic_hi_irq,
85};
86
87static void isa_irq_handler(struct irq_desc *desc)
88{
89 unsigned int isa_irq = *(unsigned char *)PCIIACK_BASE;
90
91 if (isa_irq < _ISA_IRQ(0) || isa_irq >= _ISA_IRQ(16)) {
92 do_bad_IRQ(desc);
93 return;
94 }
95
96 generic_handle_irq(isa_irq);
97}
98
99static struct resource pic1_resource = {
100 .name = "pic1",
101 .start = 0x20,
102 .end = 0x3f,
103};
104
105static struct resource pic2_resource = {
106 .name = "pic2",
107 .start = 0xa0,
108 .end = 0xbf,
109};
110
111void __init isa_init_irq(unsigned int host_irq)
112{
113 unsigned int irq;
114
115 /*
116 * Setup, and then probe for an ISA PIC
117 * If the PIC is not there, then we
118 * ignore the PIC.
119 */
120 outb(value: 0x11, port: PIC_LO);
121 outb(value: _ISA_IRQ(0), port: PIC_MASK_LO); /* IRQ number */
122 outb(value: 0x04, port: PIC_MASK_LO); /* Slave on Ch2 */
123 outb(value: 0x01, port: PIC_MASK_LO); /* x86 */
124 outb(value: 0xf5, port: PIC_MASK_LO); /* pattern: 11110101 */
125
126 outb(value: 0x11, port: PIC_HI);
127 outb(value: _ISA_IRQ(8), port: PIC_MASK_HI); /* IRQ number */
128 outb(value: 0x02, port: PIC_MASK_HI); /* Slave on Ch1 */
129 outb(value: 0x01, port: PIC_MASK_HI); /* x86 */
130 outb(value: 0xfa, port: PIC_MASK_HI); /* pattern: 11111010 */
131
132 outb(value: 0x0b, port: PIC_LO);
133 outb(value: 0x0b, port: PIC_HI);
134
135 if (inb(port: PIC_MASK_LO) == 0xf5 && inb(port: PIC_MASK_HI) == 0xfa) {
136 outb(value: 0xff, port: PIC_MASK_LO);/* mask all IRQs */
137 outb(value: 0xff, port: PIC_MASK_HI);/* mask all IRQs */
138 } else {
139 printk(KERN_INFO "IRQ: ISA PIC not found\n");
140 host_irq = (unsigned int)-1;
141 }
142
143 if (host_irq != (unsigned int)-1) {
144 for (irq = _ISA_IRQ(0); irq < _ISA_IRQ(8); irq++) {
145 irq_set_chip_and_handler(irq, &isa_lo_chip,
146 handle_level_irq);
147 irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
148 }
149
150 for (irq = _ISA_IRQ(8); irq < _ISA_IRQ(16); irq++) {
151 irq_set_chip_and_handler(irq, &isa_hi_chip,
152 handle_level_irq);
153 irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
154 }
155
156 request_resource(root: &ioport_resource, new: &pic1_resource);
157 request_resource(root: &ioport_resource, new: &pic2_resource);
158
159 irq = IRQ_ISA_CASCADE;
160 if (request_irq(irq, handler: no_action, flags: 0, name: "cascade", NULL))
161 pr_err("Failed to request irq %u (cascade)\n", irq);
162
163 irq_set_chained_handler(host_irq, isa_irq_handler);
164
165 /*
166 * On the NetWinder, don't automatically
167 * enable ISA IRQ11 when it is requested.
168 * There appears to be a missing pull-up
169 * resistor on this line.
170 */
171 if (machine_is_netwinder())
172 irq_modify_status(_ISA_IRQ(11),
173 IRQ_NOREQUEST | IRQ_NOPROBE, IRQ_NOAUTOEN);
174 }
175}
176
177
178

source code of linux/arch/arm/mach-footbridge/isa-irq.c