[RFC PATCH 0/3] ACPI PCI support for arm64

On Fri, Dec 04, 2015 at 12:11:30AM +0530, Jayachandran C. wrote:

On Thu, Dec 03, 2015 at 10:56:28AM +0000, Lorenzo Pieralisi wrote:

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[CC'ing Tomasz]

On Thu, Dec 03, 2015 at 03:54:43AM +0530, Jayachandran C wrote:

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This is a very simple and generic implementation of a PCI host controller
based on ACPI. This approach does not pull in the MMCONFIG and ECAM code
from x86.

Why ? Tomasz's patchset does not move MMCONFIG and ECAM code to the generic
PCI layer for fun,

Honestly, Lorenzo, I can see that it was not fun :)

Ok, maybe you have not noticed it was done on Bjorn's request to
consolidate ECAM (ie pulling that code out of x86) instead of reinventing
the wheel for arm64.

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it is generic code and should be shared by all
architectures and most importantly we should not add more churn on
top of it which would complicate consolidation even further.

There is no need for such a common/generic infrastructure to
walk thru a simple table. In my opinion, trying to do this added
a lot of complexity into what should be a very simple patchset.

The x86 code has to deal with a lot more fw/hw issues and I fail
to see why that mess should be brought into the a new architecture.

See above. We can't keep adding code that does the same thing as
code already in the mainline.

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It is important for us to have a working ACPI based PCI host controller
implementation for arm64, so I thought I would post this as a simple
and less disruptive alternative.

It is important for everyone but that's not a reason granting shortcuts.

 
I am suggesting a simpler (and maybe better) implementation, which
is much easier to review and merge - not a shortcut.

You are suggesting adding code to parse the MCFG table, it exists today
and should be consolidated instead of adding on top of it.

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This is tested with arm64 QEMU and OVMF. Comments are very welcome.

Tomasz's patch went through several review cycles, please help review
it and test it, that's my comment.

A new version should be posted soon, previous version here:

https://lkml.org/lkml/2015/10/27/504

It seems to be v1, I did not see any ACKs from maintainers either -
sorry if I am missing something here.

That patchset went through several reviews already, they just reset the
version. I agree with you it is time we got this done, with Tomasz's code,
your code or any combination thereof, please help us get this through,
thanks.

Lorenzo