[PATCH 10/17] ARM: update atag-to-fdt code to be endian agnostic

[Nicolas Pitre]

On Mon, 11 Feb 2013, Ben Dooks wrote:

> On 09/02/13 12:05, Russell King - ARM Linux wrote:
> > On Fri, Feb 08, 2013 at 11:17:40PM +0000, Ben Dooks wrote:
> > > -	if (atag->hdr.tag != ATAG_CORE ||
> > > -	    (atag->hdr.size != tag_size(tag_core)&&
> > > -	     atag->hdr.size != 2))
> > > +	if (atag->hdr.tag != atag32_to_cpu(ATAG_CORE) ||
> > > +	    (atag->hdr.size != atag32_to_cpu(tag_size(tag_core))&&
> > > +	     atag->hdr.size != atag32_to_cpu(2)))
> > 
> > This is wrong.  You're saying that "ATAG_CORE" is in LE32 format.  It
> > isn't.  It's in CPU endian format.  If you want to do this kind of thing,
> > you also need to define cpu_to_atag32() macros as well, otherwise this
> > will cause sparse warnings.
> > 
> > > -			initrd_start = atag->u.initrd.start;
> > > -			initrd_size = atag->u.initrd.size;
> > > +			initrd_start = atag32_to_cpu(atag->u.initrd.start);
> > > +			initrd_size = atag32_to_cpu(____atag->u.initrd.size);
> > 
> > Where did those four underscores come from?  Has this been built?
> 
> I probably missed building this one. I've been mostly testing with DT
> based systems.

Is this BE8 mode available on old systems?  Or, will those BE8 
capable old systems have BE userland compiled for them?

Where I want to get to is: do we need to support BE8 mode for ATAG based 
systems at all, given that most if not all the modern ones should be DT 
based now?  Making the ATAG code BE8 aware is looking to be quite 
invasive for potentially no users at all.


Nicolas