From patchwork Mon Feb 15 07:51:36 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicola Mazzucato X-Patchwork-Id: 12087791 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=-11.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_GIT autolearn=ham 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 1D2E7C433DB for ; Mon, 15 Feb 2021 07:49:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C32FE64E6D for ; Mon, 15 Feb 2021 07:49:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229758AbhBOHtw (ORCPT ); Mon, 15 Feb 2021 02:49:52 -0500 Received: from foss.arm.com ([217.140.110.172]:60422 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229597AbhBOHtw (ORCPT ); Mon, 15 Feb 2021 02:49:52 -0500 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 76CF8101E; Sun, 14 Feb 2021 23:49:05 -0800 (PST) Received: from ubuntu.arm.com (unknown [10.57.16.99]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id A13F93F40C; Sun, 14 Feb 2021 23:49:03 -0800 (PST) From: Nicola Mazzucato To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org, sudeep.holla@arm.com, rjw@rjwysocki.net, vireshk@kernel.org, cristian.marussi@arm.com Cc: morten.rasmussen@arm.com, chris.redpath@arm.com, ionela.voinescu@arm.com, nicola.mazzucato@arm.com Subject: [PATCH v7 0/3] CPUFreq: Add support for opp-sharing cpus Date: Mon, 15 Feb 2021 07:51:36 +0000 Message-Id: <20210215075139.30772-1-nicola.mazzucato@arm.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Hi Viresh, In this V7 posting I have reworked the CPUFreq scmi driver in a different way as suggested in v6. Essentially I believe it is more efficient to keep the support for opp-shared in the _init() stage, rather than moving everything to _probe(), storing whatever is required and reuse it only once in _init(). The reasons for this are: - scmi-cpufreq has no init cases that would require a deferred probe. - therefore, moving the all the cpus initialisation to probe, whilst possible, will result in a waste of memory, since we need to store cpumask and freq_table only for them to be reused just once later on at init. - it does not appear to be functional justification for moving the init code to probe, which results in unnecessary overhead for both coding and review. - this change is much smaller and only one patch required (1 file changed, 52 insertions, 20 deletions) compared to a version where we first move init code to _probe and later add support for opp-v2 (2 patches, 1 file changed, 194+34 insertions, 44+9 deletions, version with a linked list). - this v7 implementation is much easier to maintain. Many thanks, Nicola [v7] * Bring back common stuff for CPUs from _init stage to _probe * Remove patch "scmi-cpufreq: Move CPU initialisation to probe" This v7 is based on Linux 5.11-rc6 [v6] * Remove deferred probe, not occurring * Move common stuff for CPUs from _init stage to _probe This V6 is rebased on next-20210111 [v5] * Rework documentation of opp-shared within OPP node * Register EM only for the first CPU within cpumask in driver * Add check for nr_opp in driver before registering EM * Add comments on both dev_pm_opp_get_opp_count in driver * Remove redundant ret=0 in driver This v5 is rebased on top of: next-20201208 + Lukasz Luba's patches [1] [v4] * Remove unconditional set of opp_table->shared_opp to exclusive * Add implementation for scmi-cpufreq * Change subject These patches are on top of: next-20201201 + Lukasz Luba's patches (waiting for Rafael) [1] [v3] * Remove proposal for new 'cpu-performance-dependencies' as we instead can reuse the opp table. * Update documentation for devicetree/bindings/opp * Minor changes within opp to support empty opp table * Rework the RFC by adding a second proposal [v2] * Fix errors when running make dt_binding_check * Improve commit message description for the dt-binding * Add RFC for implementation in cpufreq-core and one of its drivers. Nicola Mazzucato (2): scmi-cpufreq: Remove deferred probe scmi-cpufreq: Get opp_shared_cpus from opp-v2 for EM Sudeep Holla (1): cpufreq: blacklist Arm Vexpress platforms in cpufreq-dt-platdev drivers/cpufreq/cpufreq-dt-platdev.c | 2 + drivers/cpufreq/scmi-cpufreq.c | 70 +++++++++++++++++++++------- 2 files changed, 54 insertions(+), 18 deletions(-)