[Skiboot] [PATCH 07/16] core: hardcode P9 large decrementer width
stewart at linux.ibm.com
Wed Feb 13 14:38:23 AEDT 2019
Michael Neuling <mikey at neuling.org> writes:
> 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?
Not really? I'll drop this patch for the time being.
OPAL Architect, IBM.
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