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
|
/*
* This file is part of the coreboot project.
*
* Copyright (C) 2004 Tyan Computer
* Written by Yinghai Lu <yhlu@tyan.com> for Tyan Computer.
* Copyright (C) 2006,2007 AMD
* Written by Yinghai Lu <yinghai.lu@amd.com> for AMD.
*
* 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.
*
* 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>
#define SMBHSTSTAT 0x1
#define SMBHSTPRTCL 0x0
#define SMBHSTCMD 0x3
#define SMBXMITADD 0x2
#define SMBHSTDAT0 0x4
#define SMBHSTDAT1 0x5
/* Between 1-10 seconds, We should never timeout normally
* Longer than this is just painful when a timeout condition occurs.
*/
#define SMBUS_TIMEOUT (100*1000*10)
static inline void smbus_delay(void)
{
outb(0x80, 0x80);
}
static int smbus_wait_until_done(unsigned smbus_io_base)
{
unsigned long loops;
loops = SMBUS_TIMEOUT;
do {
unsigned char val;
smbus_delay();
val = inb(smbus_io_base + SMBHSTSTAT);
if ( (val & 0xff) != 0) {
return 0;
}
} while (--loops);
return -3;
}
static int do_smbus_recv_byte(unsigned smbus_io_base, unsigned device)
{
unsigned char global_status_register;
unsigned char byte;
/* set the device I'm talking to */
outb(((device & 0x7f) << 1)|1 , smbus_io_base + SMBXMITADD);
smbus_delay();
/* byte data recv */
outb(0x05, smbus_io_base + SMBHSTPRTCL);
smbus_delay();
/* poll for transaction completion */
if (smbus_wait_until_done(smbus_io_base) < 0) {
return -3;
}
global_status_register = inb(smbus_io_base + SMBHSTSTAT) & 0x80; /* lose check */
/* read results of transaction */
byte = inb(smbus_io_base + SMBHSTCMD);
if (global_status_register != 0x80) { // lose check, otherwise it should be 0
return -1;
}
return byte;
}
static int do_smbus_send_byte(unsigned smbus_io_base, unsigned device, unsigned char val)
{
unsigned global_status_register;
outb(val, smbus_io_base + SMBHSTDAT0);
smbus_delay();
/* set the command... */
outb(val, smbus_io_base + SMBHSTCMD);
smbus_delay();
/* set the device I'm talking to */
outb(((device & 0x7f) << 1) | 0, smbus_io_base + SMBXMITADD);
smbus_delay();
/* set up for a byte data write */
outb(0x04, smbus_io_base + SMBHSTPRTCL);
smbus_delay();
/* poll for transaction completion */
if (smbus_wait_until_done(smbus_io_base) < 0) {
return -3;
}
global_status_register = inb(smbus_io_base + SMBHSTSTAT) & 0x80; /* lose check */
if (global_status_register != 0x80) {
return -1;
}
return 0;
}
static int do_smbus_read_byte(unsigned smbus_io_base, unsigned device, unsigned address)
{
unsigned char global_status_register;
unsigned char byte;
/* set the device I'm talking to */
outb(((device & 0x7f) << 1)|1 , smbus_io_base + SMBXMITADD);
smbus_delay();
/* set the command/address... */
outb(address & 0xff, smbus_io_base + SMBHSTCMD);
smbus_delay();
/* byte data read */
outb(0x07, smbus_io_base + SMBHSTPRTCL);
smbus_delay();
/* poll for transaction completion */
if (smbus_wait_until_done(smbus_io_base) < 0) {
return -3;
}
global_status_register = inb(smbus_io_base + SMBHSTSTAT) & 0x80; /* lose check */
/* read results of transaction */
byte = inb(smbus_io_base + SMBHSTDAT0);
if (global_status_register != 0x80) { // lose check, otherwise it should be 0
return -1;
}
return byte;
}
static int do_smbus_write_byte(unsigned smbus_io_base, unsigned device, unsigned address, unsigned char val)
{
unsigned global_status_register;
outb(val, smbus_io_base + SMBHSTDAT0);
smbus_delay();
/* set the device I'm talking to */
outb(((device & 0x7f) << 1) | 0, smbus_io_base + SMBXMITADD);
smbus_delay();
outb(address & 0xff, smbus_io_base + SMBHSTCMD);
smbus_delay();
/* set up for a byte data write */
outb(0x06, smbus_io_base + SMBHSTPRTCL);
smbus_delay();
/* poll for transaction completion */
if (smbus_wait_until_done(smbus_io_base) < 0) {
return -3;
}
global_status_register = inb(smbus_io_base + SMBHSTSTAT) & 0x80; /* lose check */
if (global_status_register != 0x80) {
return -1;
}
return 0;
}
|
