diff options
| author | Arthur Heymans <arthur@aheymans.xyz> | 2018-01-22 01:26:53 +0100 |
|---|---|---|
| committer | Patrick Georgi <pgeorgi@google.com> | 2018-04-09 09:31:11 +0000 |
| commit | 97b337b252fe67f8ffb7a98f70f08835513920ba (patch) | |
| tree | 393392768e234b0b99c0b909e5ce1502a64c2b10 | |
| parent | f7dc972fde66d93143c3f6927087c13ae74a4828 (diff) | |
device/dram/ddr2.c: Add methods to compute to identify dram
DDR2 DIMMs are uniquely defined by SPD byte 64 till 72 and 93 till
98. Compute a crc16 over that data to provide a solid way to check
DIMM identify.
Reuse the crc16 function from ddr3.c to do this.
Change-Id: I3c0c42786197f9b4eb3e42261c10ff5e4266120f
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/23345
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
| -rw-r--r-- | src/device/dram/ddr2.c | 24 | ||||
| -rw-r--r-- | src/device/dram/ddr3.c | 6 | ||||
| -rw-r--r-- | src/include/device/dram/common.h | 2 | ||||
| -rw-r--r-- | src/include/device/dram/ddr2.h | 1 |
4 files changed, 30 insertions, 3 deletions
diff --git a/src/device/dram/ddr2.c b/src/device/dram/ddr2.c index 921679c584..0d395c4315 100644 --- a/src/device/dram/ddr2.c +++ b/src/device/dram/ddr2.c @@ -72,6 +72,30 @@ u8 spd_ddr2_calc_checksum(u8 *spd, int len) } /** + * \brief Calculate the CRC of a DDR2 SPD unique identifier + * + * @param spd pointer to raw SPD data + * @param len length of data in SPD + * + * @return the CRC of SPD data bytes 64..72 and 93..98, or 0 + * when spd data is truncated. + */ +u16 spd_ddr2_calc_unique_crc(const u8 *spd, int len) +{ + u8 id_bytes[15]; + int i, j = 0; + if (len < 98) + /* Not enough bytes available to get the CRC */ + return 0; + for (i = 64; i <= 72; i++) + id_bytes[j++] = spd[i]; + for (i = 93; i <= 98; i++) + id_bytes[j++] = spd[i]; + + return ddr3_crc16(id_bytes, 15); +} + +/** * \brief Return size of SPD. * * Returns size of SPD. Usually 128 Byte. diff --git a/src/device/dram/ddr3.c b/src/device/dram/ddr3.c index 87aa3c5362..67f30092ea 100644 --- a/src/device/dram/ddr3.c +++ b/src/device/dram/ddr3.c @@ -46,7 +46,7 @@ int spd_dimm_is_registered_ddr3(enum spd_dimm_type type) return 0; } -static u16 crc16(const u8 *ptr, int n_crc) +u16 ddr3_crc16(const u8 *ptr, int n_crc) { int i; u16 crc = 0; @@ -87,7 +87,7 @@ u16 spd_ddr3_calc_crc(u8 *spd, int len) /* Not enough bytes available to get the CRC */ return 0; - return crc16(spd, n_crc); + return ddr3_crc16(spd, n_crc); } /** @@ -104,7 +104,7 @@ u16 spd_ddr3_calc_unique_crc(u8 *spd, int len) /* Not enough bytes available to get the CRC */ return 0; - return crc16(&spd[117], 11); + return ddr3_crc16(&spd[117], 11); } /** diff --git a/src/include/device/dram/common.h b/src/include/device/dram/common.h index 47023704fe..31cdb2bb5b 100644 --- a/src/include/device/dram/common.h +++ b/src/include/device/dram/common.h @@ -67,4 +67,6 @@ enum spd_status { SPD_STATUS_INVALID_FIELD, }; +u16 ddr3_crc16(const u8 *ptr, int n_crc); + #endif /* DEVICE_DRAM_COMMON_H */ diff --git a/src/include/device/dram/ddr2.h b/src/include/device/dram/ddr2.h index 4aad1bcd8f..9bbbfe9652 100644 --- a/src/include/device/dram/ddr2.h +++ b/src/include/device/dram/ddr2.h @@ -179,5 +179,6 @@ int spd_decode_ddr2(struct dimm_attr_ddr2_st *dimm, u8 spd[SPD_SIZE_MAX_DDR2]); void dram_print_spd_ddr2(const struct dimm_attr_ddr2_st *dimm); void normalize_tck(u32 *tclk); u8 spd_get_msbs(u8 c); +u16 spd_ddr2_calc_unique_crc(const u8 *spd, int len); #endif /* DEVICE_DRAM_DDR2L_H */ |