Re: [PATCH v3 00/3] MIPS: SGI-IP27 rework part2

[Christoph Hellwig]

On Tue, May 07, 2019 at 05:48:20PM +0200, Thomas Bogendoerfer wrote:
> > I had a look and the code is really, really MIPS specific, actually
> > I would be interested in understanding how many platforms it supports,
> > it is not even FW configurable.
> 
> it's MIPS only and used in basically 3 different SGI platforms.

Actually this isn't quite true, this whole infraÑtructure was also
shared by the SGI IA64 systems.

The early SN1 prototypes were basically just IP35 systems with IA64
CPUs glued in, and even the later SN2 that were released as Altix
shared the same xtalk + bridge infrastructure, just with some hardware
updates.  It just turned out SGI at some point decided to hide all that
in firmware.  Linux 2.4 was still accessing this natively, but the code
was a mess.  I tried to consolidate it with the mips version at that
point, but SGI decided that hiding it under firmware calls was easier
as they could just move the messy code there.

So, not it isn't really MIPS only in theory, although in practice it
very much is..