1/*
2 *  linux/arch/arm/mach-footbridge/irq.c
3 *
4 *  Copyright (C) 1996-2000 Russell King
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 *  Changelog:
11 *   22-Aug-1998 RMK	Restructured IRQ routines
12 *   03-Sep-1998 PJB	Merged CATS support
13 *   20-Jan-1998 RMK	Started merge of EBSA286, CATS and NetWinder
14 *   26-Jan-1999 PJB	Don't use IACK on CATS
15 *   16-Mar-1999 RMK	Added autodetect of ISA PICs
16 */
17#include <linux/ioport.h>
18#include <linux/interrupt.h>
19#include <linux/list.h>
20#include <linux/init.h>
21#include <linux/io.h>
22#include <linux/spinlock.h>
23
24#include <asm/mach/irq.h>
25
26#include <mach/hardware.h>
27#include <asm/hardware/dec21285.h>
28#include <asm/irq.h>
29#include <asm/mach-types.h>
30
31#include "common.h"
32
33static void isa_mask_pic_lo_irq(struct irq_data *d)
34{
35	unsigned int mask = 1 << (d->irq & 7);
36
37	outb(inb(PIC_MASK_LO) | mask, PIC_MASK_LO);
38}
39
40static void isa_ack_pic_lo_irq(struct irq_data *d)
41{
42	unsigned int mask = 1 << (d->irq & 7);
43
44	outb(inb(PIC_MASK_LO) | mask, PIC_MASK_LO);
45	outb(0x20, PIC_LO);
46}
47
48static void isa_unmask_pic_lo_irq(struct irq_data *d)
49{
50	unsigned int mask = 1 << (d->irq & 7);
51
52	outb(inb(PIC_MASK_LO) & ~mask, PIC_MASK_LO);
53}
54
55static struct irq_chip isa_lo_chip = {
56	.irq_ack	= isa_ack_pic_lo_irq,
57	.irq_mask	= isa_mask_pic_lo_irq,
58	.irq_unmask	= isa_unmask_pic_lo_irq,
59};
60
61static void isa_mask_pic_hi_irq(struct irq_data *d)
62{
63	unsigned int mask = 1 << (d->irq & 7);
64
65	outb(inb(PIC_MASK_HI) | mask, PIC_MASK_HI);
66}
67
68static void isa_ack_pic_hi_irq(struct irq_data *d)
69{
70	unsigned int mask = 1 << (d->irq & 7);
71
72	outb(inb(PIC_MASK_HI) | mask, PIC_MASK_HI);
73	outb(0x62, PIC_LO);
74	outb(0x20, PIC_HI);
75}
76
77static void isa_unmask_pic_hi_irq(struct irq_data *d)
78{
79	unsigned int mask = 1 << (d->irq & 7);
80
81	outb(inb(PIC_MASK_HI) & ~mask, PIC_MASK_HI);
82}
83
84static struct irq_chip isa_hi_chip = {
85	.irq_ack	= isa_ack_pic_hi_irq,
86	.irq_mask	= isa_mask_pic_hi_irq,
87	.irq_unmask	= isa_unmask_pic_hi_irq,
88};
89
90static void isa_irq_handler(struct irq_desc *desc)
91{
92	unsigned int isa_irq = *(unsigned char *)PCIIACK_BASE;
93
94	if (isa_irq < _ISA_IRQ(0) || isa_irq >= _ISA_IRQ(16)) {
95		do_bad_IRQ(desc);
96		return;
97	}
98
99	generic_handle_irq(isa_irq);
100}
101
102static struct irqaction irq_cascade = {
103	.handler = no_action,
104	.name = "cascade",
105};
106
107static struct resource pic1_resource = {
108	.name	= "pic1",
109	.start	= 0x20,
110	.end	= 0x3f,
111};
112
113static struct resource pic2_resource = {
114	.name	= "pic2",
115	.start	= 0xa0,
116	.end	= 0xbf,
117};
118
119void __init isa_init_irq(unsigned int host_irq)
120{
121	unsigned int irq;
122
123	/*
124	 * Setup, and then probe for an ISA PIC
125	 * If the PIC is not there, then we
126	 * ignore the PIC.
127	 */
128	outb(0x11, PIC_LO);
129	outb(_ISA_IRQ(0), PIC_MASK_LO);	/* IRQ number		*/
130	outb(0x04, PIC_MASK_LO);	/* Slave on Ch2		*/
131	outb(0x01, PIC_MASK_LO);	/* x86			*/
132	outb(0xf5, PIC_MASK_LO);	/* pattern: 11110101	*/
133
134	outb(0x11, PIC_HI);
135	outb(_ISA_IRQ(8), PIC_MASK_HI);	/* IRQ number		*/
136	outb(0x02, PIC_MASK_HI);	/* Slave on Ch1		*/
137	outb(0x01, PIC_MASK_HI);	/* x86			*/
138	outb(0xfa, PIC_MASK_HI);	/* pattern: 11111010	*/
139
140	outb(0x0b, PIC_LO);
141	outb(0x0b, PIC_HI);
142
143	if (inb(PIC_MASK_LO) == 0xf5 && inb(PIC_MASK_HI) == 0xfa) {
144		outb(0xff, PIC_MASK_LO);/* mask all IRQs	*/
145		outb(0xff, PIC_MASK_HI);/* mask all IRQs	*/
146	} else {
147		printk(KERN_INFO "IRQ: ISA PIC not found\n");
148		host_irq = (unsigned int)-1;
149	}
150
151	if (host_irq != (unsigned int)-1) {
152		for (irq = _ISA_IRQ(0); irq < _ISA_IRQ(8); irq++) {
153			irq_set_chip_and_handler(irq, &isa_lo_chip,
154						 handle_level_irq);
155			irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
156		}
157
158		for (irq = _ISA_IRQ(8); irq < _ISA_IRQ(16); irq++) {
159			irq_set_chip_and_handler(irq, &isa_hi_chip,
160						 handle_level_irq);
161			irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
162		}
163
164		request_resource(&ioport_resource, &pic1_resource);
165		request_resource(&ioport_resource, &pic2_resource);
166		setup_irq(IRQ_ISA_CASCADE, &irq_cascade);
167
168		irq_set_chained_handler(host_irq, isa_irq_handler);
169
170		/*
171		 * On the NetWinder, don't automatically
172		 * enable ISA IRQ11 when it is requested.
173		 * There appears to be a missing pull-up
174		 * resistor on this line.
175		 */
176		if (machine_is_netwinder())
177			irq_modify_status(_ISA_IRQ(11),
178				IRQ_NOREQUEST | IRQ_NOPROBE, IRQ_NOAUTOEN);
179	}
180}
181
182
183