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=-9.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 49524C433E1 for ; Fri, 21 Aug 2020 16:32:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1D95B22B47 for ; Fri, 21 Aug 2020 16:32:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gerhold.net header.i=@gerhold.net header.b="M/KVTksU" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728273AbgHUQcx (ORCPT ); Fri, 21 Aug 2020 12:32:53 -0400 Received: from mo4-p01-ob.smtp.rzone.de ([85.215.255.52]:18647 "EHLO mo4-p01-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728122AbgHUQcQ (ORCPT ); Fri, 21 Aug 2020 12:32:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1598027524; s=strato-dkim-0002; d=gerhold.net; h=In-Reply-To:References:Message-ID:Subject:Cc:To:From:Date: X-RZG-CLASS-ID:X-RZG-AUTH:From:Subject:Sender; bh=5oM6hmHrkxSTh2VeiPEAHTyoVLjwfurKxWYpMhitciA=; b=M/KVTksU1p3DnoGrWCOFV3S16GhMXigs6zNTYa6Ps/mQHpp7FoTQWk90YclJeUCZBk vaQ1Zx86QhUZ814akr4NwjdgA8WMmr9eqoP4j5lff+v0GMOfFNVyvtJCTz7UHEvVAMQP 84c2RMMWhKEjSQo1nZOJtkm7V56+696yIE73JaH1YT2P1nmqxURvDepFmwc2QqlX1vZI dGMpTmxSCW0gfw56YedVk2WOsT9u0+cfw7Vejr2etSAcU0jNzi1Zop2stgtLj5PwEby8 /xzScXcrR7NCfd4P/6HMrccilo8bnsZ+PMzTdGdPWfCf8hmdYIW4fstVZo8pkP+GAyM+ ITWw== X-RZG-AUTH: ":P3gBZUipdd93FF5ZZvYFPugejmSTVR2nRPhVOQ/OcYgojyw4j34+u26zEodhPgRDZ8j7Ic/Fboo=" X-RZG-CLASS-ID: mo00 Received: from gerhold.net by smtp.strato.de (RZmta 46.10.7 DYNA|AUTH) with ESMTPSA id g0b6c1w7LGW2KXw (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Fri, 21 Aug 2020 18:32:02 +0200 (CEST) Date: Fri, 21 Aug 2020 18:31:52 +0200 From: Stephan Gerhold To: Viresh Kumar Cc: "Rafael J. Wysocki" , Kevin Hilman , Ulf Hansson , Nishanth Menon , Stephen Boyd , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Niklas Cassel Subject: Re: [RFC PATCH 2/3] opp: Set required OPPs in reverse order when scaling down Message-ID: <20200821163152.GA3422@gerhold.net> References: <20200730080146.25185-1-stephan@gerhold.net> <20200730080146.25185-3-stephan@gerhold.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200730080146.25185-3-stephan@gerhold.net> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Viresh, On Thu, Jul 30, 2020 at 10:01:45AM +0200, Stephan Gerhold wrote: > The OPP core already has well-defined semantics to ensure required > OPPs/regulators are set before/after the frequency change, depending > on if we scale up or down. > > Similar requirements might exist for the order of required OPPs > when multiple power domains need to be scaled for a frequency change. > > For example, on Qualcomm platforms using CPR (Core Power Reduction), > we need to scale the VDDMX and CPR power domain. When scaling up, > MX should be scaled up before CPR. When scaling down, CPR should be > scaled down before MX. > > In general, if there are multiple "required-opps" in the device tree > I would expect that the order is either irrelevant, or there is some > dependency between the power domains. In that case, the power domains > should be scaled down in reverse order. > > This commit updates _set_required_opps() to set required OPPs in > reverse order when scaling down. > > Signed-off-by: Stephan Gerhold This patch does not apply anymore after the cleanup you pushed to opp/linux-next. I would be happy to send a v2 with that fixed. On my other OPP patch set you mentioned that you might apply these directly with some of your own changes - would you also prefer to do it yourself in this case or should I send a v2? Still looking for your feedback on both patch sets by the way! :) Thanks! Stephan > --- > Related discussion: https://lore.kernel.org/linux-arm-msm/20200525194443.GA11851@flawful.org/ > > The advantage of this approach is that the CPR driver does not need > to bother with the VDDMX power domain at all - the requirements > can be fully described within the device tree, see e.g. [1]. > An alternative option would be to modify the CPR driver to make these votes. > > [1]: https://lore.kernel.org/linux-arm-msm/20200507104603.GA581328@gerhold.net/2-msm8916-vdd-mx.patch > --- > drivers/opp/core.c | 30 +++++++++++++++++++++--------- > 1 file changed, 21 insertions(+), 9 deletions(-) > > diff --git a/drivers/opp/core.c b/drivers/opp/core.c > index f7a476b55069..f93f551c911e 100644 > --- a/drivers/opp/core.c > +++ b/drivers/opp/core.c > @@ -799,7 +799,7 @@ static int _set_required_opp(struct device *dev, struct device *pd_dev, > /* This is only called for PM domain for now */ > static int _set_required_opps(struct device *dev, > struct opp_table *opp_table, > - struct dev_pm_opp *opp) > + struct dev_pm_opp *opp, bool up) > { > struct opp_table **required_opp_tables = opp_table->required_opp_tables; > struct device **genpd_virt_devs = opp_table->genpd_virt_devs; > @@ -821,12 +821,24 @@ static int _set_required_opps(struct device *dev, > */ > mutex_lock(&opp_table->genpd_virt_dev_lock); > > - for (i = 0; i < opp_table->required_opp_count; i++) { > - pd_dev = genpd_virt_devs[i]; > + if (up) { > + /* Scaling up? Set required OPPs in normal order */ > + for (i = 0; i < opp_table->required_opp_count; i++) { > + pd_dev = genpd_virt_devs[i]; > > - ret = _set_required_opp(dev, pd_dev, opp, i); > - if (ret) > - break; > + ret = _set_required_opp(dev, pd_dev, opp, i); > + if (ret) > + break; > + } > + } else { > + /* Scaling down? Set required OPPs in reverse order */ > + for (i = opp_table->required_opp_count - 1; i >= 0; i--) { > + pd_dev = genpd_virt_devs[i]; > + > + ret = _set_required_opp(dev, pd_dev, opp, i); > + if (ret) > + break; > + } > } > mutex_unlock(&opp_table->genpd_virt_dev_lock); > > @@ -914,7 +926,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq) > opp_table->regulator_enabled = false; > } > > - ret = _set_required_opps(dev, opp_table, NULL); > + ret = _set_required_opps(dev, opp_table, NULL, false); > goto put_opp_table; > } > > @@ -973,7 +985,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq) > > /* Scaling up? Configure required OPPs before frequency */ > if (freq >= old_freq) { > - ret = _set_required_opps(dev, opp_table, opp); > + ret = _set_required_opps(dev, opp_table, opp, true); > if (ret) > goto put_opp; > } > @@ -993,7 +1005,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq) > > /* Scaling down? Configure required OPPs after frequency */ > if (!ret && freq < old_freq) { > - ret = _set_required_opps(dev, opp_table, opp); > + ret = _set_required_opps(dev, opp_table, opp, false); > if (ret) > dev_err(dev, "Failed to set required opps: %d\n", ret); > } > -- > 2.27.0 >