Change in coreboot[master]: Rename MMCONF Kconfigs to ECAM_MMCONF

[Nico Huber (Code Review)]

Attention is currently required from: Raul Rangel, Mariusz Szafrański, Jonathan Zhang, Paul Menzel, Stefan Reinauer, Kyösti Mälkki, Andrey Petrov, Patrick Rudolph, Anjaneya "Reddy" Chagam, Johnny Lin, Suresh Bellampalli, Morgan Jang, Michal Motyl, Alexander Couzens, Felix Held, Shelley Chen, Furquan Shaikh, Lance Zhao, Jason Glenesk, Martin Roth, Damien Zammit, Lee Leahy, Marshall Dawson, Tim Wawrzynczak, Vanessa Eusebio, Huang Jin.
Nico Huber has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/57333 )

Change subject: Rename MMCONF Kconfigs to ECAM_MMCONF
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Patch Set 5:

(2 comments)

Commit Message:

https://review.coreboot.org/c/coreboot/+/57333/comment/ca635a53_a113b593 
PS4, Line 9: the MMCONF Kconfigs only use the Enhanced Configuration
           : Access mechanism (ECAM) method
> Reading following two docs again: […]

The IO/MMIO distinction seems x86 specific to me, where we have two
mechanisms concurrently. I'd say all other platforms simply need to
implement some PCI OPS, without any special notion. They can use
`device/pci_mmio_ops.h` for this, but don't have to.

Patchset:

PS5: 
Can we please back up a little and discuss this on the mailing list first?
I've skimmed through the comments and it seems there is a lot of confusion
both for authors and reviewers what is architecture specific and what isn't.
And so far I see no reasoning about requirements; it looks like this patch
is just growing in uncontrolled directions.

I'd like to start with some simple questions, e.g.

* Does QC actually call their mechanism MMCONF(IG)?
* Does any other project use the MMCONF term for more than coreboot currently does?
* What does/should the term MMCONF comprise? Isn't it it about (directly) memory mapping PCI(e) config space? which QC doesn't do, as it seems