ddr_spd.c
3.14 KB
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
/*
* Copyright 2008-2014 Freescale Semiconductor, Inc.
*
* SPDX-License-Identifier: GPL-2.0
*/
#include <common.h>
#include <ddr_spd.h>
/* used for ddr1 and ddr2 spd */
static int
spd_check(const u8 *buf, u8 spd_rev, u8 spd_cksum)
{
unsigned int cksum = 0;
unsigned int i;
/*
* Check SPD revision supported
* Rev 1.X or less supported by this code
*/
if (spd_rev >= 0x20) {
printf("SPD revision %02X not supported by this code\n",
spd_rev);
return 1;
}
if (spd_rev > 0x13) {
printf("SPD revision %02X not verified by this code\n",
spd_rev);
}
/*
* Calculate checksum
*/
for (i = 0; i < 63; i++) {
cksum += *buf++;
}
cksum &= 0xFF;
if (cksum != spd_cksum) {
printf("SPD checksum unexpected. "
"Checksum in SPD = %02X, computed SPD = %02X\n",
spd_cksum, cksum);
return 1;
}
return 0;
}
unsigned int
ddr1_spd_check(const ddr1_spd_eeprom_t *spd)
{
const u8 *p = (const u8 *)spd;
return spd_check(p, spd->spd_rev, spd->cksum);
}
unsigned int
ddr2_spd_check(const ddr2_spd_eeprom_t *spd)
{
const u8 *p = (const u8 *)spd;
return spd_check(p, spd->spd_rev, spd->cksum);
}
/*
* CRC16 compute for DDR3 SPD
* Copied from DDR3 SPD spec.
*/
static int
crc16(char *ptr, int count)
{
int crc, i;
crc = 0;
while (--count >= 0) {
crc = crc ^ (int)*ptr++ << 8;
for (i = 0; i < 8; ++i)
if (crc & 0x8000)
crc = crc << 1 ^ 0x1021;
else
crc = crc << 1;
}
return crc & 0xffff;
}
unsigned int
ddr3_spd_check(const ddr3_spd_eeprom_t *spd)
{
char *p = (char *)spd;
int csum16;
int len;
char crc_lsb; /* byte 126 */
char crc_msb; /* byte 127 */
/*
* SPD byte0[7] - CRC coverage
* 0 = CRC covers bytes 0~125
* 1 = CRC covers bytes 0~116
*/
len = !(spd->info_size_crc & 0x80) ? 126 : 117;
csum16 = crc16(p, len);
crc_lsb = (char) (csum16 & 0xff);
crc_msb = (char) (csum16 >> 8);
if (spd->crc[0] == crc_lsb && spd->crc[1] == crc_msb) {
return 0;
} else {
printf("SPD checksum unexpected.\n"
"Checksum lsb in SPD = %02X, computed SPD = %02X\n"
"Checksum msb in SPD = %02X, computed SPD = %02X\n",
spd->crc[0], crc_lsb, spd->crc[1], crc_msb);
return 1;
}
}
unsigned int ddr4_spd_check(const struct ddr4_spd_eeprom_s *spd)
{
char *p = (char *)spd;
int csum16;
int len;
char crc_lsb; /* byte 126 */
char crc_msb; /* byte 127 */
len = 126;
csum16 = crc16(p, len);
crc_lsb = (char) (csum16 & 0xff);
crc_msb = (char) (csum16 >> 8);
if (spd->crc[0] != crc_lsb || spd->crc[1] != crc_msb) {
printf("SPD checksum unexpected.\n"
"Checksum lsb in SPD = %02X, computed SPD = %02X\n"
"Checksum msb in SPD = %02X, computed SPD = %02X\n",
spd->crc[0], crc_lsb, spd->crc[1], crc_msb);
return 1;
}
p = (char *)((ulong)spd + 128);
len = 126;
csum16 = crc16(p, len);
crc_lsb = (char) (csum16 & 0xff);
crc_msb = (char) (csum16 >> 8);
if (spd->mod_section.uc[126] != crc_lsb ||
spd->mod_section.uc[127] != crc_msb) {
printf("SPD checksum unexpected.\n"
"Checksum lsb in SPD = %02X, computed SPD = %02X\n"
"Checksum msb in SPD = %02X, computed SPD = %02X\n",
spd->mod_section.uc[126],
crc_lsb, spd->mod_section.uc[127],
crc_msb);
return 1;
}
return 0;
}