[RFC PATCH 1/1] powerpc/embedded6xx: Add support for Motorola/Emerson MVME5100.

[Scott Wood]

On Tue, 2013-08-13 at 08:57 +1100, Stephen N Chivers wrote:
> Scott Wood <scottwood at freescale.com> wrote on 08/09/2013 04:07:24 AM:
> 
> > From: Scott Wood <scottwood at freescale.com>
> > To: Kumar Gala <galak at kernel.crashing.org>
> > Cc: Stephen N Chivers <schivers at csc.com.au>, <paulus at samba.org>, 
> > <linuxppc-dev at lists.ozlabs.org>, Chris Proctor <cproctor at csc.com.au>
> > Date: 08/09/2013 04:08 AM
> > Subject: Re: [RFC PATCH 1/1] powerpc/embedded6xx: Add support for 
> > Motorola/Emerson MVME5100.
> > 
> > On Thu, 2013-08-08 at 10:30 -0500, Kumar Gala wrote:
> > > Also, we don't take full defconfigs in the tree, look at 'make 
> > savedefconfig'
> > 
> > Why does this board need its own defconfig at all?  Just add it to
> > ppc6xx_defconfig.
> 
> The boards firmware as stated above is PPCBug. PPCBug is not Open Firmware
> compatible.
> 
> There is no U-Boot support for the board.

I'm not sure why that precludes the use of ppc6xx_defconfig...

> In ppc6xx_defconfig the e100 network device and NFS support is modular and
> that forces the use of an initrd.

OK, then let's enable those in ppc6xx_defconfig.  We do in a lot of the
other defconfigs (such as 85xx and derivatives).

> PPCBugs network boot command takes only one file argument and so makes
> it difficult to use an initrd.
> 
> So the choices are:
>         - Providing a defconfig for the board,
>         - Building the kernel with the initrd embedded in it,
>         - Finding an alternative boot loader,
>         - Doing the board support for U-Boot.
> The first choice is simple and documents the configuration of the
> board without mixing it into ppc6xx_defconfig.

The first choice means your board would get much less build-testing, and
would increase maintenance costs of defconfig changes (and/or lead to
divergence from other defconfigs that doesn't actually have anything to
do with this board or its use cases).

The fifth choice is "add what you need to ppc6xx_defconfig".  Within
reason of course, but I think a common PCI network device and NFS root
support is reasonable.

-Scott