From: Sowjanya Komatineni <skomatineni@nvidia.com>
To: Sudeep Holla <sudeep.holla@arm.com>
Cc: <thierry.reding@gmail.com>, <jonathanh@nvidia.com>,
<daniel.lezcano@linaro.org>, <robh+dt@kernel.org>,
<ksitaraman@nvidia.com>, <sanjayc@nvidia.com>,
<linux-tegra@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<linux-pm@vger.kernel.org>, <devicetree@vger.kernel.org>
Subject: Re: [PATCH v1 3/5] dt-bindings: arm: Add cpu-idle-states to Tegra194 CPU nodes
Date: Mon, 8 Mar 2021 10:32:17 -0800 [thread overview]
Message-ID: <4cebf482-a2f8-5a79-a2f6-4ccd7d31c6ad@nvidia.com> (raw)
In-Reply-To: <20210308043755.llvdsuz2jwvweovb@bogus>
On 3/7/21 8:37 PM, Sudeep Holla wrote:
> On Wed, Mar 03, 2021 at 10:08:10PM -0800, Sowjanya Komatineni wrote:
>> This patch adds cpu-idle-states and corresponding state nodes to
>> Tegra194 CPU in dt-binding document
>>
> I see that this platform has PSCI support. Can you care to explain why
> you need additional DT bindings and driver for PSCI based CPU suspend.
> Until the reasons are convincing, consider NACK from my side for this
> driver and DT bindings. You should be really using those bindings and
> the driver may be with minor changes there.
>
MCE firmware is in charge of state transition for Tegra194 carmel CPUs.
For run-time state transitions, need to provide state request along with
its residency time to MCE firmware which is running in the background.
State min residency is updated into power_state value along with state
id that is passed to psci_cpu_suspend_enter
Also states cross-over idle times need to be provided to MCE firmware.
MCE firmware decides on state transition based on these inputs along
with its background work load.
So, Tegra specific CPU idle driver is required mainly to provide
cross-over thresholds from DT and run time idle state information to MCE
firmware through Tegra MCE communication APIs.
Allowing cross-over threshold through DT allows users to vary idle time
thresholds for state transitions based on different use-cases.
next prev parent reply other threads:[~2021-03-08 18:33 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-04 6:08 [PATCH v1 0/5] Add cpuidle support for Tegra194 Sowjanya Komatineni
2021-03-04 6:08 ` [PATCH v1 1/5] MAINTAINERS: Add Tegra CPUIDLE driver section Sowjanya Komatineni
2021-03-04 8:01 ` Daniel Lezcano
2021-03-04 6:08 ` [PATCH v1 2/5] firmware: tegra: Add Tegra194 MCE ARI driver Sowjanya Komatineni
2021-03-04 6:08 ` [PATCH v1 3/5] dt-bindings: arm: Add cpu-idle-states to Tegra194 CPU nodes Sowjanya Komatineni
2021-03-04 20:47 ` Rob Herring
2021-03-08 4:37 ` Sudeep Holla
2021-03-08 18:32 ` Sowjanya Komatineni [this message]
2021-03-10 23:19 ` Sowjanya Komatineni
2021-03-11 2:52 ` Sudeep Holla
2021-03-11 21:11 ` Sowjanya Komatineni
2021-03-16 5:38 ` Sudeep Holla
[not found] ` <08ac26c1-8257-4c6d-d274-595fee28a00f@nvidia.com>
2021-03-16 6:57 ` Sudeep Holla
[not found] ` <4b21f4c7-19cd-fcea-dd1b-9203be60a523@nvidia.com>
2021-03-15 19:26 ` Sowjanya Komatineni
2021-03-16 7:18 ` Sudeep Holla
2021-03-16 11:24 ` Sowjanya Komatineni
2021-03-04 6:08 ` [PATCH v1 4/5] cpuidle: Add Tegra194 cpuidle driver Sowjanya Komatineni
2021-03-05 13:50 ` Dmitry Osipenko
2021-03-04 6:08 ` [PATCH v1 5/5] arm64: dts: tegra194: Add CPU idle states Sowjanya Komatineni
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