Re: [patch 2.5] PCI: allow alternative methods for probing the BARs

Grant Grundler (grundler@cup.hp.com)
Wed, 08 Jan 2003 14:34:13 -0800


Ivan Kokshaysky wrote:
> On Tue, Jan 07, 2003 at 12:17:00PM -0800, Grant Grundler wrote:
> > BTW, please don't equate PCI controller instance number with PCI Domain.
>
> I agree, it's quite confusing. However, I don't think that the PCI spec
> defines "PCI controller" or "PCI domain" terms, it's pretty much
> implementation specific.

Oh. The definition I was using is based on which PCI devices can do
peer-to-peer transactions. ie a "PCI Domain" is defined by the
PCI MMIO address space routing.

> Assuming that each PCI controller can handle up to 256 bridged buses,
> the unique PCI controller index and PCI bus number is all that userspace
> needs to know in order to properly identify devices in the system.

yes - that makes sense for configuration space accesses.
I can see why you'd call this a "PCI Domain" as well.

The platforms I was commenting on can only generate config cycles below
a PCI "Host Bus Adapter" (aka controller).

thanks,
grant
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