Hi all,
I tried to boot a walnut board with a 256 ECC DIMM using u-boot 0.3.0, but didn't succeed. When examining the code in the function spd_sdram in cpu/ppc4xx/spd_sdram, I found that the ECC configuration code is probably wrong. I suppose, that the following lines
/* now check for ECC ability of module. We only support ECC * on 32 bit wide devices with 8 bit ECC. */ if ( (read_spd(11)==2) && ((read_spd(6)==40) || (read_spd(14)==8)) ){ sdram0_ecccfg=0xf<<SDRAM0_ECCCFG_SHIFT; ecc_on = 1;
should be replaced with
/* now check for ECC ability of module. We only support ECC * on 32 bit wide devices with 8 bit ECC. */ ==> if ( (read_spd(11)==2) && ((read_spd(6)==40) && read_spd(14)==8)) ){ <== sdram0_ecccfg=0xf<<SDRAM0_ECCCFG_SHIFT; ecc_on = 1;
The reason is, that the if statement in the first code is also true for 72 bit ECC devices. So ECC is enabled for such a device which fails in the following. The changed code works for me with several DIMM types (32MB without ECC, 256 MB with ECC and without ECC), but I'm not an expert with all types of SDRAM and so I'm not sure if I fully understood the code in that place. Any ideas, comments?
Best regards
Thomas Schäfer
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GIGA STREAM - UMTS Technologies GmbH
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