From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 91E4DC4332D for ; Tue, 16 Mar 2021 07:19:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 64CA065007 for ; Tue, 16 Mar 2021 07:19:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232139AbhCPHSh (ORCPT ); Tue, 16 Mar 2021 03:18:37 -0400 Received: from foss.arm.com ([217.140.110.172]:50050 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231630AbhCPHSS (ORCPT ); Tue, 16 Mar 2021 03:18:18 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 12BABD6E; Tue, 16 Mar 2021 00:18:18 -0700 (PDT) Received: from bogus (unknown [10.163.66.225]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 443473F792; Tue, 16 Mar 2021 00:18:14 -0700 (PDT) Date: Tue, 16 Mar 2021 07:18:11 +0000 From: Sudeep Holla To: Sowjanya Komatineni Cc: thierry.reding@gmail.com, jonathanh@nvidia.com, daniel.lezcano@linaro.org, robh+dt@kernel.org, ksitaraman@nvidia.com, sanjayc@nvidia.com, Lorenzo Pieralisi , Sudeep Holla , 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 Message-ID: <20210316071811.5mqcatmmbvrask2p@bogus> References: <1614838092-30398-1-git-send-email-skomatineni@nvidia.com> <1614838092-30398-4-git-send-email-skomatineni@nvidia.com> <20210308043755.llvdsuz2jwvweovb@bogus> <4cebf482-a2f8-5a79-a2f6-4ccd7d31c6ad@nvidia.com> <20210311025138.o4ub4j2ss725zpv4@bogus> <08ac26c1-8257-4c6d-d274-595fee28a00f@nvidia.com> <4b21f4c7-19cd-fcea-dd1b-9203be60a523@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4b21f4c7-19cd-fcea-dd1b-9203be60a523@nvidia.com> User-Agent: NeoMutt/20171215 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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