HS mode in RPi
Daisuke Aoyama
aoyama at peach.ne.jp
Sun Jan 18 08:03:18 UTC 2015
Hi,
r277307 add bcm2835_sdhci_hs=1, but this is wrong.
It does not cover HS problem. The quirk and HS switching is not same.
It's only one of problems on some SD card.
I'm using bcm2835_sdhci_hispd_bit but this may not useful.
HS mode on emmc=100MHz and core=250MHz cause SD card corruption.
To avoid clock domain crossing, you need emmc=250MHz and bcm2835_sdhci_hs=1.
But emmc=250MHz means running as 41MHz on HS mode(250MHz / 2N divider).
However, it seems Linux use emmc=250MHz by default.
I suggest use emmc=250MHz or keep bcm2835_sdhci_hs=0 by default at this time.
Regards,
--
Daisuke Aoyama
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