Messages in this thread | | | Date | Tue, 16 Mar 2021 07:18:11 +0000 | From | Sudeep Holla <> | Subject | Re: [PATCH v1 3/5] dt-bindings: arm: Add cpu-idle-states to Tegra194 CPU nodes |
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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
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