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

Russell King
2005-12-15T13:44:52Z

On Thu, Dec 15, 2005 at 10:06:57AM +0000, Russell King wrote:
> On Thu, Dec 15, 2005 at 10:27:13AM +0100, Pierre Ossman wrote:
> > The spec I have says that this is a single block command. So such
> > trickery would not work. It isn't explicit about padding so it might be
> > possible to pad the data (since password length is specified in the
> > data). If not, then we either ignore this function or have a system
> > where we can detect limited hosts and print warnings.
>
> What we need is someone with the real MMC spec to tell us about the
> requirements here.

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?

--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of: 2.6 Serial core