Subject: Re: [PATCH 00/18] ARM/ARM64: Support hierarchical CPU arrangement for PSCI

From: Lorenzo Pieralisi <[email-masked]>
Date: Mon, 10 Jun 2019 18:16:08 +0100

On Mon, Jun 10, 2019 at 05:54:39PM +0200, Ulf Hansson wrote:

[...]

> My summary from the earlier ones, is that because the PSCI spec
> includes support for OSI, we should also support it in the kernel (and
> ATF). In a discussion offlist, Lorenzo agreed that it's okay to add,
> without an apple to apple comparison. Maybe Lorenzo can fill in and
> state this publicly, to save us all some time?

The comparison should have been made before even requesting PSCI OSI
mode changes to the specifications, so we have a chip on our shoulders
anyway.

We will enable PSCI OSI but that's not where the problem lies, enabling
PSCI OSI from a firmware perspective should take 10 lines of code,
not:

 drivers/firmware/psci/Makefile                |   2 +-
 drivers/firmware/psci/psci.c                  | 219 ++++++++--
 drivers/firmware/psci/psci.h                  |  29 ++
 drivers/firmware/psci/psci_pm_domain.c        | 403 ++++++++++++++++++

I have some concerns about these changes that I will state in the
relevant patches.

> My final point in regards to the OSI mode support, it's a minor part
> of the series. I don't see how that should hurt from a maintenance
> point of view, or perhaps I am wrong? In any case, I offer my help
> with review/maintenance in any form as you may see need/fit.

I will go through the series but most of this code should move
to core PM code, it has nothing to do with PSCI.

BTW, apologies for the delay, I was away.

Thanks,
Lorenzo

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