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

From: Frantisek Dufka dufkaf at seznam.cz
Date: Tue Oct 3 13:37:54 EEST 2006

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.

Details and kernel here

Again this specific kernel image was not tested by me as I have 
different kernel with MMC drivers compiled as modules.

99% of work was done by Philip Langdale, patches available on LKML:


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