blob: 80456bc9ff458c90ad7357b7957cb9ec385da434 (
plain)
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
|
/*
* This file is part of the coreboot project.
*
* Copyright (C) 2005 Yinghai Lu <yinghailu@gmail.com>
* Copyright (C) 2009 coresystems GmbH
*
* 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; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <device/smbus_def.h>
#include "i82801gx.h"
static void smbus_delay(void)
{
inb(0x80);
}
static int smbus_wait_until_ready(u16 smbus_base)
{
unsigned loops = SMBUS_TIMEOUT;
unsigned char byte;
do {
smbus_delay();
if (--loops == 0)
break;
byte = inb(smbus_base + SMBHSTSTAT);
} while (byte & 1);
return loops ? 0 : -1;
}
static int smbus_wait_until_done(u16 smbus_base)
{
unsigned loops = SMBUS_TIMEOUT;
unsigned char byte;
do {
smbus_delay();
if (--loops == 0)
break;
byte = inb(smbus_base + SMBHSTSTAT);
} while ((byte & 1) || (byte & ~((1 << 6) | (1 << 0))) == 0);
return loops ? 0 : -1;
}
static int do_smbus_read_byte(unsigned smbus_base, unsigned device, unsigned address)
{
unsigned char global_status_register;
unsigned char byte;
if (smbus_wait_until_ready(smbus_base) < 0) {
return SMBUS_WAIT_UNTIL_READY_TIMEOUT;
}
/* Setup transaction */
/* Disable interrupts */
outb(inb(smbus_base + SMBHSTCTL) & (~1), smbus_base + SMBHSTCTL);
/* Set the device I'm talking too */
outb(((device & 0x7f) << 1) | 1, smbus_base + SMBXMITADD);
/* Set the command/address... */
outb(address & 0xff, smbus_base + SMBHSTCMD);
/* Set up for a byte data read */
outb((inb(smbus_base + SMBHSTCTL) & 0xe3) | (0x2 << 2),
(smbus_base + SMBHSTCTL));
/* Clear any lingering errors, so the transaction will run */
outb(inb(smbus_base + SMBHSTSTAT), smbus_base + SMBHSTSTAT);
/* Clear the data byte... */
outb(0, smbus_base + SMBHSTDAT0);
/* Start the command */
outb((inb(smbus_base + SMBHSTCTL) | 0x40),
smbus_base + SMBHSTCTL);
/* Poll for transaction completion */
if (smbus_wait_until_done(smbus_base) < 0) {
return SMBUS_WAIT_UNTIL_DONE_TIMEOUT;
}
global_status_register = inb(smbus_base + SMBHSTSTAT);
/* Ignore the "In Use" status... */
global_status_register &= ~(3 << 5);
/* Read results of transaction */
byte = inb(smbus_base + SMBHSTDAT0);
if (global_status_register != (1 << 1)) {
return SMBUS_ERROR;
}
return byte;
}
|
