1 /*
2 * Copyright 2008-2014 Freescale Semiconductor, Inc.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * Version 2 as published by the Free Software Foundation.
7 */
8
9 #include <common.h>
10 #include <ddr_spd.h>
11
12 /* used for ddr1 and ddr2 spd */
13 static int
spd_check(const u8 * buf,u8 spd_rev,u8 spd_cksum)14 spd_check(const u8 *buf, u8 spd_rev, u8 spd_cksum)
15 {
16 unsigned int cksum = 0;
17 unsigned int i;
18
19 /*
20 * Check SPD revision supported
21 * Rev 1.X or less supported by this code
22 */
23 if (spd_rev >= 0x20) {
24 printf("SPD revision %02X not supported by this code\n",
25 spd_rev);
26 return 1;
27 }
28 if (spd_rev > 0x13) {
29 printf("SPD revision %02X not verified by this code\n",
30 spd_rev);
31 }
32
33 /*
34 * Calculate checksum
35 */
36 for (i = 0; i < 63; i++) {
37 cksum += *buf++;
38 }
39 cksum &= 0xFF;
40
41 if (cksum != spd_cksum) {
42 printf("SPD checksum unexpected. "
43 "Checksum in SPD = %02X, computed SPD = %02X\n",
44 spd_cksum, cksum);
45 return 1;
46 }
47
48 return 0;
49 }
50
51 unsigned int
ddr1_spd_check(const ddr1_spd_eeprom_t * spd)52 ddr1_spd_check(const ddr1_spd_eeprom_t *spd)
53 {
54 const u8 *p = (const u8 *)spd;
55
56 return spd_check(p, spd->spd_rev, spd->cksum);
57 }
58
59 unsigned int
ddr2_spd_check(const ddr2_spd_eeprom_t * spd)60 ddr2_spd_check(const ddr2_spd_eeprom_t *spd)
61 {
62 const u8 *p = (const u8 *)spd;
63
64 return spd_check(p, spd->spd_rev, spd->cksum);
65 }
66
67 /*
68 * CRC16 compute for DDR3 SPD
69 * Copied from DDR3 SPD spec.
70 */
71 static int
crc16(char * ptr,int count)72 crc16(char *ptr, int count)
73 {
74 int crc, i;
75
76 crc = 0;
77 while (--count >= 0) {
78 crc = crc ^ (int)*ptr++ << 8;
79 for (i = 0; i < 8; ++i)
80 if (crc & 0x8000)
81 crc = crc << 1 ^ 0x1021;
82 else
83 crc = crc << 1;
84 }
85 return crc & 0xffff;
86 }
87
88 unsigned int
ddr3_spd_check(const ddr3_spd_eeprom_t * spd)89 ddr3_spd_check(const ddr3_spd_eeprom_t *spd)
90 {
91 char *p = (char *)spd;
92 int csum16;
93 int len;
94 char crc_lsb; /* byte 126 */
95 char crc_msb; /* byte 127 */
96
97 /*
98 * SPD byte0[7] - CRC coverage
99 * 0 = CRC covers bytes 0~125
100 * 1 = CRC covers bytes 0~116
101 */
102
103 len = !(spd->info_size_crc & 0x80) ? 126 : 117;
104 csum16 = crc16(p, len);
105
106 crc_lsb = (char) (csum16 & 0xff);
107 crc_msb = (char) (csum16 >> 8);
108
109 if (spd->crc[0] == crc_lsb && spd->crc[1] == crc_msb) {
110 return 0;
111 } else {
112 printf("SPD checksum unexpected.\n"
113 "Checksum lsb in SPD = %02X, computed SPD = %02X\n"
114 "Checksum msb in SPD = %02X, computed SPD = %02X\n",
115 spd->crc[0], crc_lsb, spd->crc[1], crc_msb);
116 return 1;
117 }
118 }
119
ddr4_spd_check(const struct ddr4_spd_eeprom_s * spd)120 unsigned int ddr4_spd_check(const struct ddr4_spd_eeprom_s *spd)
121 {
122 char *p = (char *)spd;
123 int csum16;
124 int len;
125 char crc_lsb; /* byte 126 */
126 char crc_msb; /* byte 127 */
127
128 len = 126;
129 csum16 = crc16(p, len);
130
131 crc_lsb = (char) (csum16 & 0xff);
132 crc_msb = (char) (csum16 >> 8);
133
134 if (spd->crc[0] != crc_lsb || spd->crc[1] != crc_msb) {
135 printf("SPD checksum unexpected.\n"
136 "Checksum lsb in SPD = %02X, computed SPD = %02X\n"
137 "Checksum msb in SPD = %02X, computed SPD = %02X\n",
138 spd->crc[0], crc_lsb, spd->crc[1], crc_msb);
139 return 1;
140 }
141
142 p = (char *)((ulong)spd + 128);
143 len = 126;
144 csum16 = crc16(p, len);
145
146 crc_lsb = (char) (csum16 & 0xff);
147 crc_msb = (char) (csum16 >> 8);
148
149 if (spd->mod_section.uc[126] != crc_lsb ||
150 spd->mod_section.uc[127] != crc_msb) {
151 printf("SPD checksum unexpected.\n"
152 "Checksum lsb in SPD = %02X, computed SPD = %02X\n"
153 "Checksum msb in SPD = %02X, computed SPD = %02X\n",
154 spd->mod_section.uc[126],
155 crc_lsb, spd->mod_section.uc[127],
156 crc_msb);
157 return 1;
158 }
159
160 return 0;
161 }
162