[maemo-developers] [maemo-developers] high speed (52/48Mhz) MMC mode added

[From: Koen Kooi]

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Frantisek Dufka schreef:
> Hello,
>
> This kernel enables also 52Mhz high-speed MMC mode (works on Kingston
> 2GB MMCmobile). Complete summary of changes:
>
> 1. legacy MMC cards run at 16Mhz instead of original 12Mhz (1.3x
> speedup), my 64MB card included with N770 does not work with this,
> others do work (Sandisk 1GB). I suppose the card is buggy as max DTR in
> CSD is honored in MMC driver and card claims it can handle up to 20Mhz.
>
> 2. MMCplus/mobile cards run at 24 or 48Mhz only if cards claim to
> support v4 specs, report its speed in EXT_CSD structure (26 vs 52Mhz)
> and switch command to high-speed mode (CMD 6) worked.

With my 1GB sandisk RS-MMC:

time dd if=/dev/mmcblk0 of=/dev/null bs=8192
count=10240 # 44.13 seconds

Is that ~24MHz?


regards,

Koen
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