1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright 2008-2014 Freescale Semiconductor, Inc. 4 */ 5 6 #include <common.h> 7 #include <ddr_spd.h> 8 9 /* used for ddr1 and ddr2 spd */ 10 static int 11 spd_check(const u8 *buf, u8 spd_rev, u8 spd_cksum) 12 { 13 unsigned int cksum = 0; 14 unsigned int i; 15 16 /* 17 * Check SPD revision supported 18 * Rev 1.X or less supported by this code 19 */ 20 if (spd_rev >= 0x20) { 21 printf("SPD revision %02X not supported by this code\n", 22 spd_rev); 23 return 1; 24 } 25 if (spd_rev > 0x13) { 26 printf("SPD revision %02X not verified by this code\n", 27 spd_rev); 28 } 29 30 /* 31 * Calculate checksum 32 */ 33 for (i = 0; i < 63; i++) { 34 cksum += *buf++; 35 } 36 cksum &= 0xFF; 37 38 if (cksum != spd_cksum) { 39 printf("SPD checksum unexpected. " 40 "Checksum in SPD = %02X, computed SPD = %02X\n", 41 spd_cksum, cksum); 42 return 1; 43 } 44 45 return 0; 46 } 47 48 unsigned int 49 ddr1_spd_check(const ddr1_spd_eeprom_t *spd) 50 { 51 const u8 *p = (const u8 *)spd; 52 53 return spd_check(p, spd->spd_rev, spd->cksum); 54 } 55 56 unsigned int 57 ddr2_spd_check(const ddr2_spd_eeprom_t *spd) 58 { 59 const u8 *p = (const u8 *)spd; 60 61 return spd_check(p, spd->spd_rev, spd->cksum); 62 } 63 64 /* 65 * CRC16 compute for DDR3 SPD 66 * Copied from DDR3 SPD spec. 67 */ 68 static int 69 crc16(char *ptr, int count) 70 { 71 int crc, i; 72 73 crc = 0; 74 while (--count >= 0) { 75 crc = crc ^ (int)*ptr++ << 8; 76 for (i = 0; i < 8; ++i) 77 if (crc & 0x8000) 78 crc = crc << 1 ^ 0x1021; 79 else 80 crc = crc << 1; 81 } 82 return crc & 0xffff; 83 } 84 85 unsigned int 86 ddr3_spd_check(const ddr3_spd_eeprom_t *spd) 87 { 88 char *p = (char *)spd; 89 int csum16; 90 int len; 91 char crc_lsb; /* byte 126 */ 92 char crc_msb; /* byte 127 */ 93 94 /* 95 * SPD byte0[7] - CRC coverage 96 * 0 = CRC covers bytes 0~125 97 * 1 = CRC covers bytes 0~116 98 */ 99 100 len = !(spd->info_size_crc & 0x80) ? 126 : 117; 101 csum16 = crc16(p, len); 102 103 crc_lsb = (char) (csum16 & 0xff); 104 crc_msb = (char) (csum16 >> 8); 105 106 if (spd->crc[0] == crc_lsb && spd->crc[1] == crc_msb) { 107 return 0; 108 } else { 109 printf("SPD checksum unexpected.\n" 110 "Checksum lsb in SPD = %02X, computed SPD = %02X\n" 111 "Checksum msb in SPD = %02X, computed SPD = %02X\n", 112 spd->crc[0], crc_lsb, spd->crc[1], crc_msb); 113 return 1; 114 } 115 } 116 117 unsigned int ddr4_spd_check(const struct ddr4_spd_eeprom_s *spd) 118 { 119 char *p = (char *)spd; 120 int csum16; 121 int len; 122 char crc_lsb; /* byte 126 */ 123 char crc_msb; /* byte 127 */ 124 125 len = 126; 126 csum16 = crc16(p, len); 127 128 crc_lsb = (char) (csum16 & 0xff); 129 crc_msb = (char) (csum16 >> 8); 130 131 if (spd->crc[0] != crc_lsb || spd->crc[1] != crc_msb) { 132 printf("SPD checksum unexpected.\n" 133 "Checksum lsb in SPD = %02X, computed SPD = %02X\n" 134 "Checksum msb in SPD = %02X, computed SPD = %02X\n", 135 spd->crc[0], crc_lsb, spd->crc[1], crc_msb); 136 return 1; 137 } 138 139 p = (char *)((ulong)spd + 128); 140 len = 126; 141 csum16 = crc16(p, len); 142 143 crc_lsb = (char) (csum16 & 0xff); 144 crc_msb = (char) (csum16 >> 8); 145 146 if (spd->mod_section.uc[126] != crc_lsb || 147 spd->mod_section.uc[127] != crc_msb) { 148 printf("SPD checksum unexpected.\n" 149 "Checksum lsb in SPD = %02X, computed SPD = %02X\n" 150 "Checksum msb in SPD = %02X, computed SPD = %02X\n", 151 spd->mod_section.uc[126], 152 crc_lsb, spd->mod_section.uc[127], 153 crc_msb); 154 return 1; 155 } 156 157 return 0; 158 } 159