[Skiboot] [PATCH] Add NX P7+ support

[Dan Streetman]

On Tue, Mar 17, 2015 at 1:34 AM, Stewart Smith
<stewart at linux.vnet.ibm.com> wrote:
> Benjamin Herrenschmidt <benh at au1.ibm.com> writes:
>> On Mon, 2015-03-16 at 14:03 -0400, Dan Streetman wrote:
>>>
>>> Well the kernel driver doesn't care at all about P7/P8 except for the
>>> xscom r/w, since the xscom addrs are different between P7/P8.  As I
>>> haven't actually added any error recovery (via xscoms) to the kernel
>>> driver yet, I could remove the xscom stuff from the first kernel patch
>>> set.  However, if the kernel driver is who eventually monitors and
>>> handles NX errors, I don't see any way around r/w directly from the NX
>>> xscoms.  The P7/P8 differences should be able to be abstracted in the
>>> nx-842-xscom.h header though, and I don't think the actual driver will
>>> need to know the P num.
>>
>> I don't want linux to know about SCOMS, instead, create OPAL calls, for
>> example OPAL_GET_NX_STATUS or whatever makes sense for you.
>>
>> In any case, a XSCOM is a roundtrip to OPAL so the above won't be
>> slower.
>
> I'll merge this patch and possibly disable the 842 DT node creation
> before tagging skiboot-5.0 depending on if the patch that adds OPAL
> calls arrives in time or not.

Sorry for the delay.  I sent the patch with the NX opal calls earlier
this week, so let me know if you think it needs any adjustment.

>
> (open question: should the protocol for discovering if firmware supports
> a thing be "check device tree entry exists and OPAL calls exist" or just
> "check device tree" OR check opal call)
>