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

[Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>]

In article <4461C1F1.5080300%netbsd.org@localhost>
shige%NetBSD.org@localhost wrote:

> Why is pchb below on plb directly?
> (cf. On i386 port, mainbus -> pci -> pchb.)

Maybe difference between physical and logical structures, as Allen said.

>From software view, the PCI bridge can be seen via PCI configuration
space. It's a logical "PCI-HOST bridge" PCI device.
On real hardware, the PCI bridge is located on CPU local bus.
While it's called "pchb" on evbppc, it isn't the same device
with the former PCI-HOST bridge device seen via PCI, but a bus
controller attached to the local bus.

We shouldn't call the latter one "pchb" to avoid confusion?
(on arc it's called "necpb" and on evbmips it's "aupci", I think)
---
Izumi Tsutsui