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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C1F33C433EF for ; Wed, 11 May 2022 14:41:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243663AbiEKOl0 (ORCPT ); Wed, 11 May 2022 10:41:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53634 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244964AbiEKOlV (ORCPT ); Wed, 11 May 2022 10:41:21 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 00E3F48885; Wed, 11 May 2022 07:41:20 -0700 (PDT) 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 CBA7B1FB; Wed, 11 May 2022 07:41:20 -0700 (PDT) Received: from bogus (e103737-lin.cambridge.arm.com [10.1.197.49]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 395923F66F; Wed, 11 May 2022 07:41:19 -0700 (PDT) Date: Wed, 11 May 2022 15:41:16 +0100 From: Sudeep Holla To: Pierre Gondois Cc: linux-kernel@vger.kernel.org, Ionela.Voinescu@arm.com, Sudeep Holla , Dietmar.Eggemann@arm.com, "Rafael J. Wysocki" , Len Brown , Viresh Kumar , Robert Moore , linux-acpi@vger.kernel.org, linux-pm@vger.kernel.org, devel@acpica.org Subject: Re: [PATCH v1 4/5] cpufreq: CPPC: Enable fast_switch Message-ID: <20220511144116.ir2wyfqwdpnhkldx@bogus> References: <20220511134559.1466925-1-pierre.gondois@arm.com> <20220511134559.1466925-4-pierre.gondois@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220511134559.1466925-4-pierre.gondois@arm.com> Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Wed, May 11, 2022 at 03:45:58PM +0200, Pierre Gondois wrote: > From: Pierre Gondois > > The communication mean of the _CPC desired performance can be > PCC, System Memory, System IO, or Functional Fixed Hardware. > > commit b7898fda5bc7 ("cpufreq: Support for fast frequency switching") > fast_switching is 'for switching CPU frequencies from interrupt > context'. > Writes to SystemMemory and SystemIo are fast and suitable this. > This is not the case for PCC and might not be the case for FFH. > > Enable fast_switching for the cppc_cpufreq driver in above cases. > > Add cppc_allow_fast_switch() to check the desired performance > register address space and set fast_switching accordingly. > Reviewed-by: Sudeep Holla -- Regards, Sudeep