Re: Re: [H2200-port] MMC/SD now works on h2200

On Tue, 2005-04-26 at 15:41 -0700, Matthew Reimer wrote:
> 1. Set up PXA DMA to copy from SDIDATA.
>
> 2. Set up [SH]AMCOP's SD registers.
>
> 3. Set the interrupt controller's DREQEN bit which would then trigger the PXA
> DMA to copy directly from SDIDATA.
>
> 4. Repeat steps 1-3 for every SD transfer.

I don't exactly understand how the handshaking between the SD controller
and the DMA block would work in this case. If the DREQ bit in the IC is
permanently set then, as soon as you set DREQEN, the pxa255 will
immediately start sucking data out of SDIDATA without actually waiting
for data to be available. I think what you really need is to bring out
the SDI's DREQ onto HAMCOP DREQ directly, but that doesn't seem to be
possible.

p.
Received on Tue Apr 26 2005 - 19:23:52 EDT