SDIO multiplexing

[andrzej zaborowski]

On 28/04/2008, Werner Almesberger <werner at openmoko.org> wrote:
>  > Basically a form of SDIO multiplexing.
>  > Other options would be SPI.
>
>
> We once asked Samuel about SPI, and he said that it would be slower,
>  but still good enough. (In real life, the theoretically possible
>  maximum speed is rarely reached anyway.)
>
>  Without digging through the Atheros driver, I don't know how much work
>  it would be to put it on SPI. If the abstraction is clean, it could be
>  very simple. If not, a pain.

You'd need to also adapt the mmc/sd stack in linux/drivers/mmc/ to use
the SPI mode because it's not supported by linux at the moment.  In
this mode different MMC commands are allowed and the state machine is
a little different.  There may already be patches available somewhere.

Regards