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Paul Mackerrasf9bd1702005-10-26 16:47:42 +10001/*
2 * i8259 interrupt controller driver.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07009#include <linux/init.h>
10#include <linux/ioport.h>
11#include <linux/interrupt.h>
12#include <asm/io.h>
13#include <asm/i8259.h>
14
Paul Mackerrasf9bd1702005-10-26 16:47:42 +100015static volatile void __iomem *pci_intack; /* RO, gives us the irq vector */
Linus Torvalds1da177e2005-04-16 15:20:36 -070016
Paul Mackerrasf9bd1702005-10-26 16:47:42 +100017static unsigned char cached_8259[2] = { 0xff, 0xff };
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#define cached_A1 (cached_8259[0])
19#define cached_21 (cached_8259[1])
20
21static DEFINE_SPINLOCK(i8259_lock);
22
Paul Mackerrasf9bd1702005-10-26 16:47:42 +100023static int i8259_pic_irq_offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -070024
25/*
26 * Acknowledge the IRQ using either the PCI host bridge's interrupt
27 * acknowledge feature or poll. How i8259_init() is called determines
28 * which is called. It should be noted that polling is broken on some
29 * IBM and Motorola PReP boxes so we must use the int-ack feature on them.
30 */
Paul Mackerrasf9bd1702005-10-26 16:47:42 +100031int i8259_irq(struct pt_regs *regs)
Linus Torvalds1da177e2005-04-16 15:20:36 -070032{
33 int irq;
34
35 spin_lock(&i8259_lock);
36
37 /* Either int-ack or poll for the IRQ */
38 if (pci_intack)
Paul Mackerrasf9bd1702005-10-26 16:47:42 +100039 irq = readb(pci_intack);
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 else {
41 /* Perform an interrupt acknowledge cycle on controller 1. */
42 outb(0x0C, 0x20); /* prepare for poll */
43 irq = inb(0x20) & 7;
44 if (irq == 2 ) {
45 /*
46 * Interrupt is cascaded so perform interrupt
47 * acknowledge on controller 2.
48 */
49 outb(0x0C, 0xA0); /* prepare for poll */
50 irq = (inb(0xA0) & 7) + 8;
51 }
52 }
53
54 if (irq == 7) {
55 /*
56 * This may be a spurious interrupt.
57 *
58 * Read the interrupt status register (ISR). If the most
59 * significant bit is not set then there is no valid
60 * interrupt.
61 */
62 if (!pci_intack)
63 outb(0x0B, 0x20); /* ISR register */
64 if(~inb(0x20) & 0x80)
65 irq = -1;
66 }
67
68 spin_unlock(&i8259_lock);
Paul Mackerrasf9bd1702005-10-26 16:47:42 +100069 return irq + i8259_pic_irq_offset;
70}
71
Linus Torvalds1da177e2005-04-16 15:20:36 -070072static void i8259_mask_and_ack_irq(unsigned int irq_nr)
73{
74 unsigned long flags;
75
76 spin_lock_irqsave(&i8259_lock, flags);
Paul Mackerrasf9bd1702005-10-26 16:47:42 +100077 irq_nr -= i8259_pic_irq_offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 if (irq_nr > 7) {
79 cached_A1 |= 1 << (irq_nr-8);
Paul Mackerrasf9bd1702005-10-26 16:47:42 +100080 inb(0xA1); /* DUMMY */
81 outb(cached_A1, 0xA1);
82 outb(0x20, 0xA0); /* Non-specific EOI */
83 outb(0x20, 0x20); /* Non-specific EOI to cascade */
Linus Torvalds1da177e2005-04-16 15:20:36 -070084 } else {
85 cached_21 |= 1 << irq_nr;
Paul Mackerrasf9bd1702005-10-26 16:47:42 +100086 inb(0x21); /* DUMMY */
87 outb(cached_21, 0x21);
88 outb(0x20, 0x20); /* Non-specific EOI */
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 }
90 spin_unlock_irqrestore(&i8259_lock, flags);
91}
92
93static void i8259_set_irq_mask(int irq_nr)
94{
95 outb(cached_A1,0xA1);
96 outb(cached_21,0x21);
97}
98
99static void i8259_mask_irq(unsigned int irq_nr)
100{
101 unsigned long flags;
102
103 spin_lock_irqsave(&i8259_lock, flags);
Paul Mackerrasf9bd1702005-10-26 16:47:42 +1000104 irq_nr -= i8259_pic_irq_offset;
105 if (irq_nr < 8)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 cached_21 |= 1 << irq_nr;
107 else
108 cached_A1 |= 1 << (irq_nr-8);
109 i8259_set_irq_mask(irq_nr);
110 spin_unlock_irqrestore(&i8259_lock, flags);
111}
112
113static void i8259_unmask_irq(unsigned int irq_nr)
114{
115 unsigned long flags;
116
117 spin_lock_irqsave(&i8259_lock, flags);
Paul Mackerrasf9bd1702005-10-26 16:47:42 +1000118 irq_nr -= i8259_pic_irq_offset;
119 if (irq_nr < 8)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 cached_21 &= ~(1 << irq_nr);
121 else
122 cached_A1 &= ~(1 << (irq_nr-8));
123 i8259_set_irq_mask(irq_nr);
124 spin_unlock_irqrestore(&i8259_lock, flags);
125}
126
Benjamin Herrenschmidtb9e5b4e2006-07-03 19:32:51 +1000127static struct irq_chip i8259_pic = {
128 .typename = " i8259 ",
129 .mask = i8259_mask_irq,
130 .unmask = i8259_unmask_irq,
131 .mask_ack = i8259_mask_and_ack_irq,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132};
133
134static struct resource pic1_iores = {
135 .name = "8259 (master)",
136 .start = 0x20,
137 .end = 0x21,
138 .flags = IORESOURCE_BUSY,
139};
140
141static struct resource pic2_iores = {
142 .name = "8259 (slave)",
143 .start = 0xa0,
144 .end = 0xa1,
145 .flags = IORESOURCE_BUSY,
146};
147
148static struct resource pic_edgectrl_iores = {
149 .name = "8259 edge control",
150 .start = 0x4d0,
151 .end = 0x4d1,
152 .flags = IORESOURCE_BUSY,
153};
154
155static struct irqaction i8259_irqaction = {
156 .handler = no_action,
Thomas Gleixner67144652006-07-01 19:29:22 -0700157 .flags = IRQF_DISABLED,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158 .mask = CPU_MASK_NONE,
159 .name = "82c59 secondary cascade",
160};
161
162/*
163 * i8259_init()
164 * intack_addr - PCI interrupt acknowledge (real) address which will return
165 * the active irq from the 8259
166 */
Paul Mackerrasf9bd1702005-10-26 16:47:42 +1000167void __init i8259_init(unsigned long intack_addr, int offset)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168{
169 unsigned long flags;
Paul Mackerrasf9bd1702005-10-26 16:47:42 +1000170 int i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171
172 spin_lock_irqsave(&i8259_lock, flags);
Paul Mackerrasf9bd1702005-10-26 16:47:42 +1000173 i8259_pic_irq_offset = offset;
174
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 /* init master interrupt controller */
176 outb(0x11, 0x20); /* Start init sequence */
177 outb(0x00, 0x21); /* Vector base */
178 outb(0x04, 0x21); /* edge tiggered, Cascade (slave) on IRQ2 */
179 outb(0x01, 0x21); /* Select 8086 mode */
180
181 /* init slave interrupt controller */
182 outb(0x11, 0xA0); /* Start init sequence */
183 outb(0x08, 0xA1); /* Vector base */
184 outb(0x02, 0xA1); /* edge triggered, Cascade (slave) on IRQ2 */
185 outb(0x01, 0xA1); /* Select 8086 mode */
186
187 /* always read ISR */
188 outb(0x0B, 0x20);
189 outb(0x0B, 0xA0);
190
191 /* Mask all interrupts */
192 outb(cached_A1, 0xA1);
193 outb(cached_21, 0x21);
194
195 spin_unlock_irqrestore(&i8259_lock, flags);
196
Benjamin Herrenschmidtb9e5b4e2006-07-03 19:32:51 +1000197 for (i = 0; i < NUM_ISA_INTERRUPTS; ++i) {
198 set_irq_chip_and_handler(offset + i, &i8259_pic,
199 handle_level_irq);
200 irq_desc[offset + i].status |= IRQ_LEVEL;
201 }
David Woodhouse9d2ba6f2005-11-05 17:54:22 +0000202
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 /* reserve our resources */
Paul Mackerrasf9bd1702005-10-26 16:47:42 +1000204 setup_irq(offset + 2, &i8259_irqaction);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205 request_resource(&ioport_resource, &pic1_iores);
206 request_resource(&ioport_resource, &pic2_iores);
207 request_resource(&ioport_resource, &pic_edgectrl_iores);
208
209 if (intack_addr != 0)
210 pci_intack = ioremap(intack_addr, 1);
Paul Mackerrasf9bd1702005-10-26 16:47:42 +1000211
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212}