Subject: Re: Trouble with SCC UART ports when moving from ppc to powerpc

From: Scott Wood <[email-masked]>
Date: Thu, 20 Mar 2008 11:24:40 -0500

On Thu, Mar 20, 2008 at 04:18:26PM +0100, Laurent Pinchart wrote:
> I don't want to kill it either. What I meant is that my first patch will not 
> care about udbg so that I can get feedback about the CPM serial driver part. 
> I'll then see how to make udbg fit into that.

OK.

> > Perhaps we should stick more initialization into the cpm udbg code, so it
> > isn't so dependent on the bootloader setup... though we'd have push the
> > CPM reset and SMC allocation earlier in such a case.
> 
> When SMC1 is used as a serial console, SMC1 is the first CPM dpram
> allocation user.

Typically yes, but I wouldn't want to depend on that...

> This means the CPM dpram allocator will allocate a buffer at the beginning
> of the dpram. As he SMC controller will already be using the 64 first
> bytes of the dpram, it will not see any difference when being
> reinitialized.

Not always.  Planetcore, for example, puts SMC parameter RAM at 0x1100
rather than zero.

> This of course depends on the boot loader allocating parameter ram at the 
> beginning of the dpram for SMC1, but we already depend on that if I'm not 
> mistaken.

We don't depend on it -- it's specified in the smc node's reg property, and
in the absence of said regions in the muram node.

-Scott