On Mon, Mar 15, 2021 at 11:13:24AM -0700, Sowjanya Komatineni wrote:

Hi Sudeep,

I see you are one of the maintainer of PSCI driver. Please add any other
right persons if you think should also agree/comment.

Can you please comment on below 2 items based on your feedback?

1. Can you please suggest on proper way of generalizing to pass state
residency time run-time along with state during state enter?

Not sure if any other drivers need this but for Tegra as MCE firmware is
in-charge of states enter and decisions, passing run-time state residency
from kernel to ATF is required and agree on not using power_state value for
this which is against PSCI spec.

Yes, I prefer you need to get this added in the PSCI specification.
I have passed this thread to the author of the specification.

2. Regarding state thresholds, although state thresholds are policy related
in Tegra cpu idle perspective these thresholds are platform specific based
on use case and mainly for MCE firmware usage to decide on state transitions
for core and core clusters as well.

From previous emails, I gather these can be moved to firmware and need not be
there in DT ?

As these are Tegra platform specific, Please comment if any other concerns
in having this configured by Tegra CPU Idle kernel driver.

I prefer not to have Tegra specific idle driver if we can get the necessary
changes in PSCI spec. We must then have just one PSCI idle driver in the
kernel.

Based on my understanding only above issue-1 is PSCI compliant related.
Please confirm.

Correct.

--
Regards,
Sudeep