[Skiboot] [PATCH 07/16] core: hardcode P9 large decrementer width

[Michael Neuling]

On Tue, 2019-02-12 at 12:23 +1100, Stewart Smith wrote:
> Oliver <oohall at gmail.com> writes:
> > On Mon, Feb 11, 2019 at 3:12 PM Stewart Smith <stewart at linux.ibm.com> wrote:
> > > Nicholas Piggin <npiggin at gmail.com> writes:
> > > > There is no good reason to "discover" the large decremeter width.
> > > > We are firmware, we know the large decrementer width.
> > > > 
> > > > Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
> > > 
> > > Oliver - do you remember the original motivation around detecting it
> > > rather than just coding how many bits there were? Was it because we were
> > > experimenting with things in sim before the HW design was finalised? Or
> > > are we just being fancy?
> > 
> > Dunno. I'm pretty sure this was one of the first bits of skiboot code
> > I wrote so either,
> > 
> > a) I was overthinking it, or
> > b) Mikey told me to.
> > 
> > I do remember having to get some mambo bugs fixed to test it though.
> > So it's possible the actual size wasn't finalised yet.
> 
> Mikey, was it (b) ?
> 
> (and at this point am *I* overthinking this? Hard-coding it is *fine*)

IIRC, we wanted to make it future proof and it was easy enough to do, so we did.

Is there a problem with auto detecting it?

Mikey