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
|
/*-
* Copyright (c) 2004 John Baldwin <jhb@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* The ELCR is a register that controls the trigger mode and polarity of
* EISA and ISA interrupts. In FreeBSD 3.x and 4.x, the ELCR was only
* consulted for determining the appropriate trigger mode of EISA
* interrupts when using an APIC. However, it seems that almost all
* systems that include PCI also include an ELCR that manages the ISA
* IRQs 0 through 15. Thus, we check for the presence of an ELCR on
* every machine by checking to see if the values found at bootup are
* sane. Note that the polarity of ISA and EISA IRQs are linked to the
* trigger mode. All edge triggered IRQs use active-hi polarity, and
* all level triggered interrupts use active-lo polarity.
*
* The format of the ELCR is simple: it is a 16-bit bitmap where bit 0
* controls IRQ 0, bit 1 controls IRQ 1, etc. If the bit is zero, the
* associated IRQ is edge triggered. If the bit is one, the IRQ is
* level triggered.
*/
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/systm.h>
#include <machine/intr_machdep.h>
#define ELCR_PORT 0x4d0
#define ELCR_MASK(irq) (1 << (irq))
static int elcr_status;
int elcr_found;
/*
* Check to see if we have what looks like a valid ELCR. We do this by
* verifying that IRQs 0, 1, 2, and 13 are all edge triggered.
*/
int
elcr_probe(void)
{
int i;
elcr_status = inb(ELCR_PORT) | inb(ELCR_PORT + 1) << 8;
if ((elcr_status & (ELCR_MASK(0) | ELCR_MASK(1) | ELCR_MASK(2) |
ELCR_MASK(8) | ELCR_MASK(13))) != 0)
return (ENXIO);
if (bootverbose) {
printf("ELCR Found. ISA IRQs programmed as:\n");
for (i = 0; i < 16; i++)
printf(" %2d", i);
printf("\n");
for (i = 0; i < 16; i++)
if (elcr_status & ELCR_MASK(i))
printf(" L");
else
printf(" E");
printf("\n");
}
if (resource_disabled("elcr", 0))
return (ENXIO);
elcr_found = 1;
return (0);
}
/*
* Returns 1 for level trigger, 0 for edge.
*/
enum intr_trigger
elcr_read_trigger(u_int irq)
{
KASSERT(elcr_found, ("%s: no ELCR was found!", __func__));
KASSERT(irq <= 15, ("%s: invalid IRQ %u", __func__, irq));
if (elcr_status & ELCR_MASK(irq))
return (INTR_TRIGGER_LEVEL);
else
return (INTR_TRIGGER_EDGE);
}
/*
* Set the trigger mode for a specified IRQ. Mode of 0 means edge triggered,
* and a mode of 1 means level triggered.
*/
void
elcr_write_trigger(u_int irq, enum intr_trigger trigger)
{
int new_status;
KASSERT(elcr_found, ("%s: no ELCR was found!", __func__));
KASSERT(irq <= 15, ("%s: invalid IRQ %u", __func__, irq));
if (trigger == INTR_TRIGGER_LEVEL)
new_status = elcr_status | ELCR_MASK(irq);
else
new_status = elcr_status & ~ELCR_MASK(irq);
if (new_status == elcr_status)
return;
elcr_status = new_status;
if (irq >= 8)
outb(ELCR_PORT + 1, elcr_status >> 8);
else
outb(ELCR_PORT, elcr_status & 0xff);
}
void
elcr_resume(void)
{
KASSERT(elcr_found, ("%s: no ELCR was found!", __func__));
outb(ELCR_PORT, elcr_status & 0xff);
outb(ELCR_PORT + 1, elcr_status >> 8);
}
|
