diff options
| -rw-r--r-- | src/device/dram/ddr3.c | 37 |
1 files changed, 30 insertions, 7 deletions
diff --git a/src/device/dram/ddr3.c b/src/device/dram/ddr3.c index 6e5c541a85..db661a9886 100644 --- a/src/device/dram/ddr3.c +++ b/src/device/dram/ddr3.c @@ -129,9 +129,10 @@ int spd_decode_ddr3(dimm_attr * dimm, spd_raw_data spd) { int ret; u16 crc, spd_crc; - u8 ftb_divisor, ftb_dividend, capacity_shift, bus_width; + u8 capacity_shift, bus_width; u8 reg8; u32 mtb; /* medium time base */ + u32 ftb; /* fine time base */ unsigned int val, param; ret = SPD_STATUS_OK; @@ -263,12 +264,6 @@ int spd_decode_ddr3(dimm_attr * dimm, spd_raw_data spd) dimm->size_mb = ((1 << (capacity_shift + (25 - 20))) * bus_width * dimm->ranks) / dimm->width; - /* Fine Timebase (FTB) Dividend/Divisor */ - /* Dividend */ - ftb_dividend = (spd[9] >> 4) & 0x0f; - /* Divisor */ - ftb_divisor = spd[9] & 0x0f; - /* Medium Timebase = * Medium Timebase (MTB) Dividend / * Medium Timebase (MTB) Divisor */ @@ -301,6 +296,34 @@ int spd_decode_ddr3(dimm_attr * dimm, spd_raw_data spd) /* Minimum Four Activate Window Delay Time (tFAWmin) */ dimm->tFAW = (((spd[28] & 0x0f) << 8) + spd[29]) * mtb; + printram(" FTB timings :"); + /* FTB is introduced in SPD revision 1.1 */ + if (spd[1] >= 0x11 && spd[9] & 0x0f) { + printram(" yes\n"); + + /* Fine timebase (1/256 ps) = + * Fine Timebase (FTB) Dividend / + * Fine Timebase (FTB) Divisor */ + ftb = (((u16) spd[9] & 0xf0) << 4) / (spd[9] & 0x0f); + + /* SPD recommends to round up the MTB part and use a negative + * FTB, so a negative rounding should be always safe */ + + /* SDRAM Minimum Cycle Time (tCKmin) correction */ + dimm->tCK += (s32)((s8) spd[34] * ftb - 500) / 1000; + /* Minimum CAS Latency Time (tAAmin) correction */ + dimm->tAA += (s32)((s8) spd[35] * ftb - 500) / 1000; + /* Minimum RAS# to CAS# Delay Time (tRCDmin) correction */ + dimm->tRCD += (s32)((s8) spd[36] * ftb - 500) / 1000; + /* Minimum Row Precharge Delay Time (tRPmin) correction */ + dimm->tRP += (s32)((s8) spd[37] * ftb - 500) / 1000; + /* Minimum Active to Active/Refresh Delay Time (tRCmin) corr. */ + dimm->tRC += (s32)((s8) spd[38] * ftb - 500) / 1000; + } + else { + printram(" no\n"); + } + /* SDRAM Optional Features */ reg8 = spd[30]; printram(" Optional features :"); |