Re: ibm4xx pci (Re: IBM405GP/GPr OPB bus_space endian (powerpc/ibm4xx/dev/opb.c))

[Jachym Holecek <freza%liberouter.org@localhost>]

> > Hmm, I think they're pretty much the same, see also below. As I
> > understand it, "PCI host bridge" == "PCI-to-${whatever} bridge
> > that on given system is used to configure the PCI bus" (eg. initiates
> > configuration cycles for given segment).
> 
> Well, I know they are the same physical device. I said they are
> different views on autoconf(9).

Aha -- sorry, I misunderstood you.

> On most port the name of pchb(4) is
> used to attach PCI-HOST bridge during configuring PCI bus,
> i.e. all pchbmatch() functions found in
>  [... list ...]
> check PCI_CLASS and PCI_SUBCLASS, or PCI_VENDOR and PCI_PRODUCT
> (and do nothing other than print product info in pchbattach() BTW).
> 
> On the other hand, some of these ports also configure these bridge
> devices at mainbus:
>  [... list ...]
> while some other ports don't have specific sources (i.e. pci bus
> is attached at mainbus directly), maybe because they are
> initialized by firmware or have no pchb variants so there
> is few thing to be done by OS during autoconf, I think.
> 
> On some ports have both "pchb* at pci?" and "pci* at pchb?"
> but it seems wrong, IMO.

That's somewhat confusing, indeed -- the 4xx would then end up
with "pchb -> pci -> pchb" if it wanted to catch the second view.
A rename sounds good then.

        -- Jachym