powerpc: udbg based backend for hvc_console

[David Gibson]

On Mon, Nov 17, 2008 at 01:41:24PM -0600, Timur Tabi wrote:
> On Thu, Oct 23, 2008 at 9:54 PM, David Gibson
> <david at gibson.dropbear.id.au> wrote:
> > This patch adds a new backend for the hvc console based on the
> > low-level udbg callbacks.  This effectively implements a working
> > runtime console in terms of the simple udbg primitives.  This is kind
> > of a hack - since udbg isn't something you really want to be using
> > routinely - but it's really useful during bringup.
> 
> David, I have a stupid question.  I already have an HVC console driver
> that works.  Do I need to do anything, other than enable HVC_UDBG, to
> get my hvc console drive to use udbg?

Um.. well.. if you have both activated, I think you can select which
HVC console backend will be used by using console=/dev/hvcNN on the
commandline, where values of NN correspond to different backends, in
order depending on link order in some complex fashion.

But if you already have a working HVC console driver, I don't see why
you'd want to use HVC_UDBG - it's essentially a bringup hack.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson