Re: [patch 0/5] Add MMC password protection (lock/unlock) support

Pierre Ossman
2005-12-15T16:01:37Z

Russell King wrote:
> Reading through the specs I have here, block sizes seem to be all over
> the place. The MMC card specs seem to imply that any block size can
> be set, from 0 bytes to 2^32-1 bytes.
>
> The PXA MMC interface specification allows the block size to be anything
> from 1 to 1023 bytes, excluding CRC. It is unclear whether a value of 0
> means 1024.
>
> The MMCI specification allows the block size to be specified as a power
> of two, from 1 to 2048 bytes, excluding CRC.
>
> Pierre - can you comment on wbsd's capabilities please?
>
>

wbsd can do 1 to 4087 (it wants CRC bytes in the size so it goes to 4095
including those). Which means I probably set incorrect sg limits... I
guess I should fix that.

sdhci, which I'm currently developing, can do up to 0x7FFF. The register
is 16-bits, but the upper bit never sticks so I assume it cannot be used.

Rgds
Pierre