Info on IO vs. Memory mapped PCI configuration ...

[Michel Lanners]

On  27 Jan, this message from vinai echoed through cyberspace:
> I am just getting into some driver programming for my work.  I read a
> bit of the PCI System Architecture book, and it talked about one of the
> main ways x86 vs the PPC did PCI configuration was through IO vs memory
> space.

Configration? That's inherently platform-dependant. The host bridge
arranges for _some_ way of configuration space access to be available.
_You_ need to know _how_ you access it from the bridge docs.

It happens that PowerPC lacks the seperate address space that is called
'IO' on i386. So yes, everything is memory-mapped on PowerPC, be it
PCI's memory space (big fat mapping often mapped 1:1), IO space (smaller
mapping) or configuration space (mapped in the host bridge's memory
space).

>  Is there an on-line reference somewhere that talks about these
> ideas or concept in more detail?

Not much that I know of... Try Intel or PCI SIG.

Cheers

Michel

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