1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
|
/*
* i8259 interrupt controller driver.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <asm/io.h>
#include <asm/i8259.h>
static volatile void __iomem *pci_intack; /* RO, gives us the irq vector */
static unsigned char cached_8259[2] = { 0xff, 0xff };
#define cached_A1 (cached_8259[0])
#define cached_21 (cached_8259[1])
static DEFINE_SPINLOCK(i8259_lock);
static int i8259_pic_irq_offset;
/*
* Acknowledge the IRQ using either the PCI host bridge's interrupt
* acknowledge feature or poll. How i8259_init() is called determines
* which is called. It should be noted that polling is broken on some
* IBM and Motorola PReP boxes so we must use the int-ack feature on them.
*/
int i8259_irq(struct pt_regs *regs)
{
int irq;
spin_lock(&i8259_lock);
/* Either int-ack or poll for the IRQ */
if (pci_intack)
irq = readb(pci_intack);
else {
/* Perform an interrupt acknowledge cycle on controller 1. */
outb(0x0C, 0x20); /* prepare for poll */
irq = inb(0x20) & 7;
if (irq == 2 ) {
/*
* Interrupt is cascaded so perform interrupt
* acknowledge on controller 2.
*/
outb(0x0C, 0xA0); /* prepare for poll */
irq = (inb(0xA0) & 7) + 8;
}
}
if (irq == 7) {
/*
* This may be a spurious interrupt.
*
* Read the interrupt status register (ISR). If the most
* significant bit is not set then there is no valid
* interrupt.
*/
if (!pci_intack)
outb(0x0B, 0x20); /* ISR register */
if(~inb(0x20) & 0x80)
irq = -1;
}
spin_unlock(&i8259_lock);
return irq + i8259_pic_irq_offset;
}
int i8259_irq_cascade(struct pt_regs *regs, void *unused)
{
return i8259_irq(regs);
}
static void i8259_mask_and_ack_irq(unsigned int irq_nr)
{
unsigned long flags;
spin_lock_irqsave(&i8259_lock, flags);
irq_nr -= i8259_pic_irq_offset;
if (irq_nr > 7) {
cached_A1 |= 1 << (irq_nr-8);
inb(0xA1); /* DUMMY */
outb(cached_A1, 0xA1);
outb(0x20, 0xA0); /* Non-specific EOI */
outb(0x20, 0x20); /* Non-specific EOI to cascade */
} else {
cached_21 |= 1 << irq_nr;
inb(0x21); /* DUMMY */
outb(cached_21, 0x21);
outb(0x20, 0x20); /* Non-specific EOI */
}
spin_unlock_irqrestore(&i8259_lock, flags);
}
static void i8259_set_irq_mask(int irq_nr)
{
outb(cached_A1,0xA1);
outb(cached_21,0x21);
}
static void i8259_mask_irq(unsigned int irq_nr)
{
unsigned long flags;
spin_lock_irqsave(&i8259_lock, flags);
irq_nr -= i8259_pic_irq_offset;
if (irq_nr < 8)
cached_21 |= 1 << irq_nr;
else
cached_A1 |= 1 << (irq_nr-8);
i8259_set_irq_mask(irq_nr);
spin_unlock_irqrestore(&i8259_lock, flags);
}
static void i8259_unmask_irq(unsigned int irq_nr)
{
unsigned long flags;
spin_lock_irqsave(&i8259_lock, flags);
irq_nr -= i8259_pic_irq_offset;
if (irq_nr < 8)
cached_21 &= ~(1 << irq_nr);
else
cached_A1 &= ~(1 << (irq_nr-8));
i8259_set_irq_mask(irq_nr);
spin_unlock_irqrestore(&i8259_lock, flags);
}
static void i8259_end_irq(unsigned int irq)
{
if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS))
&& irq_desc[irq].action)
i8259_unmask_irq(irq);
}
struct hw_interrupt_type i8259_pic = {
.typename = " i8259 ",
.enable = i8259_unmask_irq,
.disable = i8259_mask_irq,
.ack = i8259_mask_and_ack_irq,
.end = i8259_end_irq,
};
static struct resource pic1_iores = {
.name = "8259 (master)",
.start = 0x20,
.end = 0x21,
.flags = IORESOURCE_BUSY,
};
static struct resource pic2_iores = {
.name = "8259 (slave)",
.start = 0xa0,
.end = 0xa1,
.flags = IORESOURCE_BUSY,
};
static struct resource pic_edgectrl_iores = {
.name = "8259 edge control",
.start = 0x4d0,
.end = 0x4d1,
.flags = IORESOURCE_BUSY,
};
static struct irqaction i8259_irqaction = {
.handler = no_action,
.flags = IRQF_DISABLED,
.mask = CPU_MASK_NONE,
.name = "82c59 secondary cascade",
};
/*
* i8259_init()
* intack_addr - PCI interrupt acknowledge (real) address which will return
* the active irq from the 8259
*/
void __init i8259_init(unsigned long intack_addr, int offset)
{
unsigned long flags;
int i;
spin_lock_irqsave(&i8259_lock, flags);
i8259_pic_irq_offset = offset;
/* init master interrupt controller */
outb(0x11, 0x20); /* Start init sequence */
outb(0x00, 0x21); /* Vector base */
outb(0x04, 0x21); /* edge tiggered, Cascade (slave) on IRQ2 */
outb(0x01, 0x21); /* Select 8086 mode */
/* init slave interrupt controller */
outb(0x11, 0xA0); /* Start init sequence */
outb(0x08, 0xA1); /* Vector base */
outb(0x02, 0xA1); /* edge triggered, Cascade (slave) on IRQ2 */
outb(0x01, 0xA1); /* Select 8086 mode */
/* always read ISR */
outb(0x0B, 0x20);
outb(0x0B, 0xA0);
/* Mask all interrupts */
outb(cached_A1, 0xA1);
outb(cached_21, 0x21);
spin_unlock_irqrestore(&i8259_lock, flags);
for (i = 0; i < NUM_ISA_INTERRUPTS; ++i)
irq_desc[offset + i].chip = &i8259_pic;
/* reserve our resources */
setup_irq(offset + 2, &i8259_irqaction);
request_resource(&ioport_resource, &pic1_iores);
request_resource(&ioport_resource, &pic2_iores);
request_resource(&ioport_resource, &pic_edgectrl_iores);
if (intack_addr != 0)
pci_intack = ioremap(intack_addr, 1);
}
|
