blob: 7a388bb9fa10ac03915224110ebef119d9ae83e3 [file] [log] [blame]
James Yang0f2cbe32008-08-26 15:01:27 -05001/*
2 * Copyright 2008 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 */
13static int
14spd_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
Kyle Moffettc7fd27c2011-03-28 11:35:48 -040021 * Rev 1.X or less supported by this code
James Yang0f2cbe32008-08-26 15:01:27 -050022 */
York Sunbcb6c2b2010-05-07 09:12:01 -050023 if (spd_rev >= 0x20) {
James Yang0f2cbe32008-08-26 15:01:27 -050024 printf("SPD revision %02X not supported by this code\n",
25 spd_rev);
26 return 1;
27 }
York Sunbcb6c2b2010-05-07 09:12:01 -050028 if (spd_rev > 0x13) {
29 printf("SPD revision %02X not verified by this code\n",
30 spd_rev);
31 }
James Yang0f2cbe32008-08-26 15:01:27 -050032
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
51unsigned int
52ddr1_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
59unsigned int
60ddr2_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}
Dave Liuc360cea2009-03-14 12:48:30 +080066
67/*
68 * CRC16 compute for DDR3 SPD
69 * Copied from DDR3 SPD spec.
70 */
71static int
72crc16(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
88unsigned int
89ddr3_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}