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| Commit | Line | Data |
|---|---|---|
| 0f2cbe3f JY |
1 | /* |
| 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 */ | |
| 13 | static int | |
| 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 1.2 or less supported by this code | |
| 22 | */ | |
| 23 | if (spd_rev > 0x12) { | |
| 24 | printf("SPD revision %02X not supported by this code\n", | |
| 25 | spd_rev); | |
| 26 | return 1; | |
| 27 | } | |
| 28 | ||
| 29 | /* | |
| 30 | * Calculate checksum | |
| 31 | */ | |
| 32 | for (i = 0; i < 63; i++) { | |
| 33 | cksum += *buf++; | |
| 34 | } | |
| 35 | cksum &= 0xFF; | |
| 36 | ||
| 37 | if (cksum != spd_cksum) { | |
| 38 | printf("SPD checksum unexpected. " | |
| 39 | "Checksum in SPD = %02X, computed SPD = %02X\n", | |
| 40 | spd_cksum, cksum); | |
| 41 | return 1; | |
| 42 | } | |
| 43 | ||
| 44 | return 0; | |
| 45 | } | |
| 46 | ||
| 47 | unsigned int | |
| 48 | ddr1_spd_check(const ddr1_spd_eeprom_t *spd) | |
| 49 | { | |
| 50 | const u8 *p = (const u8 *)spd; | |
| 51 | ||
| 52 | return spd_check(p, spd->spd_rev, spd->cksum); | |
| 53 | } | |
| 54 | ||
| 55 | unsigned int | |
| 56 | ddr2_spd_check(const ddr2_spd_eeprom_t *spd) | |
| 57 | { | |
| 58 | const u8 *p = (const u8 *)spd; | |
| 59 | ||
| 60 | return spd_check(p, spd->spd_rev, spd->cksum); | |
| 61 | } | |
| c360ceac DL |
62 | |
| 63 | /* | |
| 64 | * CRC16 compute for DDR3 SPD | |
| 65 | * Copied from DDR3 SPD spec. | |
| 66 | */ | |
| 67 | static int | |
| 68 | crc16(char *ptr, int count) | |
| 69 | { | |
| 70 | int crc, i; | |
| 71 | ||
| 72 | crc = 0; | |
| 73 | while (--count >= 0) { | |
| 74 | crc = crc ^ (int)*ptr++ << 8; | |
| 75 | for (i = 0; i < 8; ++i) | |
| 76 | if (crc & 0x8000) | |
| 77 | crc = crc << 1 ^ 0x1021; | |
| 78 | else | |
| 79 | crc = crc << 1; | |
| 80 | } | |
| 81 | return crc & 0xffff; | |
| 82 | } | |
| 83 | ||
| 84 | unsigned int | |
| 85 | ddr3_spd_check(const ddr3_spd_eeprom_t *spd) | |
| 86 | { | |
| 87 | char *p = (char *)spd; | |
| 88 | int csum16; | |
| 89 | int len; | |
| 90 | char crc_lsb; /* byte 126 */ | |
| 91 | char crc_msb; /* byte 127 */ | |
| 92 | ||
| 93 | /* | |
| 94 | * SPD byte0[7] - CRC coverage | |
| 95 | * 0 = CRC covers bytes 0~125 | |
| 96 | * 1 = CRC covers bytes 0~116 | |
| 97 | */ | |
| 98 | ||
| 99 | len = !(spd->info_size_crc & 0x80) ? 126 : 117; | |
| 100 | csum16 = crc16(p, len); | |
| 101 | ||
| 102 | crc_lsb = (char) (csum16 & 0xff); | |
| 103 | crc_msb = (char) (csum16 >> 8); | |
| 104 | ||
| 105 | if (spd->crc[0] == crc_lsb && spd->crc[1] == crc_msb) { | |
| 106 | return 0; | |
| 107 | } else { | |
| 108 | printf("SPD checksum unexpected.\n" | |
| 109 | "Checksum lsb in SPD = %02X, computed SPD = %02X\n" | |
| 110 | "Checksum msb in SPD = %02X, computed SPD = %02X\n", | |
| 111 | spd->crc[0], crc_lsb, spd->crc[1], crc_msb); | |
| 112 | return 1; | |
| 113 | } | |
| 114 | } |