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(PIC_MASK_LO) | mask, 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(PIC_MASK_LO) | mask, PIC_MASK_LO);
42	outb(0x20, 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(PIC_MASK_LO) & ~mask, 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(PIC_MASK_HI) | mask, 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(PIC_MASK_HI) | mask, PIC_MASK_HI);
70	outb(0x62, PIC_LO);
71	outb(0x20, 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(PIC_MASK_HI) & ~mask, 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(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