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
30 static void isa_mask_pic_lo_irq(struct irq_data *d)
31 {
32 unsigned int mask = 1 << (d->irq & 7);
33
34 outb(inb(PIC_MASK_LO) | mask, PIC_MASK_LO);
35 }
36
37 static void isa_ack_pic_lo_irq(struct irq_data *d)
38 {
39 unsigned int mask = 1 << (d->irq & 7);
40
41 outb(inb(PIC_MASK_LO) | mask, PIC_MASK_LO);
42 outb(0x20, PIC_LO);
43 }
44
45 static void isa_unmask_pic_lo_irq(struct irq_data *d)
46 {
47 unsigned int mask = 1 << (d->irq & 7);
48
49 outb(inb(PIC_MASK_LO) & ~mask, PIC_MASK_LO);
50 }
51
52 static 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
58 static void isa_mask_pic_hi_irq(struct irq_data *d)
59 {
60 unsigned int mask = 1 << (d->irq & 7);
61
62 outb(inb(PIC_MASK_HI) | mask, PIC_MASK_HI);
63 }
64
65 static void isa_ack_pic_hi_irq(struct irq_data *d)
66 {
67 unsigned int mask = 1 << (d->irq & 7);
68
69 outb(inb(PIC_MASK_HI) | mask, PIC_MASK_HI);
70 outb(0x62, PIC_LO);
71 outb(0x20, PIC_HI);
72 }
73
74 static void isa_unmask_pic_hi_irq(struct irq_data *d)
75 {
76 unsigned int mask = 1 << (d->irq & 7);
77
78 outb(inb(PIC_MASK_HI) & ~mask, PIC_MASK_HI);
79 }
80
81 static 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
87 static 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
99 static struct resource pic1_resource = {
100 .name = "pic1",
101 .start = 0x20,
102 .end = 0x3f,
103 };
104
105 static struct resource pic2_resource = {
106 .name = "pic2",
107 .start = 0xa0,
108 .end = 0xbf,
109 };
110
111 void __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(0x11, PIC_LO);
121 outb(_ISA_IRQ(0), PIC_MASK_LO); /* IRQ number */
122 outb(0x04, PIC_MASK_LO); /* Slave on Ch2 */
123 outb(0x01, PIC_MASK_LO); /* x86 */
124 outb(0xf5, PIC_MASK_LO); /* pattern: 11110101 */
125
126 outb(0x11, PIC_HI);
127 outb(_ISA_IRQ(8), PIC_MASK_HI); /* IRQ number */
128 outb(0x02, PIC_MASK_HI); /* Slave on Ch1 */
129 outb(0x01, PIC_MASK_HI); /* x86 */
130 outb(0xfa, PIC_MASK_HI); /* pattern: 11111010 */
131
132 outb(0x0b, PIC_LO);
133 outb(0x0b, PIC_HI);
134
135 if (inb(PIC_MASK_LO) == 0xf5 && inb(PIC_MASK_HI) == 0xfa) {
136 outb(0xff, PIC_MASK_LO);/* mask all IRQs */
137 outb(0xff, 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(&ioport_resource, &pic1_resource);
157 request_resource(&ioport_resource, &pic2_resource);
158
159 irq = IRQ_ISA_CASCADE;
160 if (request_irq(irq, no_action, 0, "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
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