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 470EBC433F5 for ; Fri, 15 Apr 2022 06:15:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240827AbiDOGRl (ORCPT ); Fri, 15 Apr 2022 02:17:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55354 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349975AbiDOGRb (ORCPT ); Fri, 15 Apr 2022 02:17:31 -0400 Received: from mail-il1-x133.google.com (mail-il1-x133.google.com [IPv6:2607:f8b0:4864:20::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A376E3C492 for ; Thu, 14 Apr 2022 23:15:01 -0700 (PDT) Received: by mail-il1-x133.google.com with SMTP id r11so4400129ila.1 for ; Thu, 14 Apr 2022 23:15:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=QmEp/mMGdmvE393WWBsKkqLvzhV/lIHVVl2pgkJlWKw=; b=Ea5b0mKvenPORYSnxIMfP0qRj7CZ1UXeFgpAe5H/W2rXWzn5F9X8ulED/rqpBJluHo geM986PtAN2iggf05Gn1CU+7BD6TKXfzir94MtF1E1pVyPZ50vBL+UDJupZ8Ay3xt0/b XqJbGSC7k3t+1eJfmSGsNwer1Q1S0udoyi55O2188QJUYfJjchKJ4XI4eDaS43x/yDKS fpCns2xJA7mc6IKkJBmZeA0Lc0FdqOFD3PidE4WUjwKG4bCTczjFs68+iVn0/Yq1mkvt JiEqzzI9R/HNlQXKwM2Sv2aAMATrwNR4+eoqj++55rCTlOBbvd0QaJfb31LYTKeVs4XP +6Yg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=QmEp/mMGdmvE393WWBsKkqLvzhV/lIHVVl2pgkJlWKw=; b=doiFmwAjEGQqtIOUyYdIHukVc7LunvG8e5BLjfdy+/w6tvuaXxIDH6Ewo4HOo36At4 xqzc5OsyDCgse7k2u84AJP/6Z9X8LujXCFj29Htl0v0mc74e233U6l8QozVPl064rbkS PF/ya8PBgoM7hQ5CY6soz6vWkX64nf6qR5/PyIMnxJbLy710p4yFz9nFGgVlOSDzh111 k3IRhm93/5tCOme8UpeorjktbrqfILEjLKlh/5KPEcUd1nL/HgWjmLHfEVEsmiQQ+lPE wlrzUd7vGiRk7/YRAVc5mgt+KVBucLUwLM549dDC2ZCSwhZes8VDSVQgGOwb9HhGyWn6 c06A== X-Gm-Message-State: AOAM531IC87+zqcYf+pe8TRfHsCJedE1OE8/XaVaiFebRZEoxQ/7GoXP hCG+BnucTxmoMknHNViz1x1M8PF/q3zAQm6VT3kW5g== X-Google-Smtp-Source: ABdhPJwcLVQCaKCPBevFx2nnK/pH8pbVZF8DcOsfzTmPQwBuqON2D1SO/RpJYvdJAlXbD/we/fGnqSHI6X1Xd9LlmcM= X-Received: by 2002:a92:cdad:0:b0:2c6:7b76:a086 with SMTP id g13-20020a92cdad000000b002c67b76a086mr2742492ild.5.1650003300783; Thu, 14 Apr 2022 23:15:00 -0700 (PDT) MIME-Version: 1.0 References: <20220415055916.28350-1-rex-bc.chen@mediatek.com> <20220415055916.28350-11-rex-bc.chen@mediatek.com> In-Reply-To: <20220415055916.28350-11-rex-bc.chen@mediatek.com> From: Hsin-Yi Wang Date: Fri, 15 Apr 2022 14:14:34 +0800 Message-ID: Subject: Re: [PATCH V3 10/15] cpufreq: mediatek: Add counter to prevent infinite loop when tracking voltage To: Rex-BC Chen Cc: rafael@kernel.org, Viresh Kumar , Rob Herring , krzk+dt@kernel.org, Matthias Brugger , Tim Chang , roger.lu@mediatek.com, Kevin Hilman , angelogioacchino.delregno@collabora.com, linux-pm@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, Project_Global_Chrome_Upstream_Group@mediatek.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 15, 2022 at 1:59 PM Rex-BC Chen wrote: > > To prevent infinite loop when tracking voltage, we calculate the maximum > value for each platform data. > We assume min voltage is 0 and tracking target voltage using > min_volt_shift for each iteration. > The retry_max is 3 times of expeted iteration count. > > Signed-off-by: Rex-BC Chen > --- > drivers/cpufreq/mediatek-cpufreq.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c > index cc44a7a9427a..d4c00237e862 100644 > --- a/drivers/cpufreq/mediatek-cpufreq.c > +++ b/drivers/cpufreq/mediatek-cpufreq.c > @@ -86,6 +86,16 @@ static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info, > struct regulator *proc_reg = info->proc_reg; > struct regulator *sram_reg = info->sram_reg; > int pre_vproc, pre_vsram, new_vsram, vsram, vproc, ret; > + int retry_max; > + > + /* > + * We assume min voltage is 0 and tracking target voltage using > + * min_volt_shift for each iteration. > + * The retry_max is 3 times of expeted iteration count. > + */ > + retry_max = 3 * DIV_ROUND_UP(max(info->soc_data->sram_max_volt, > + info->soc_data->proc_max_volt), > + info->soc_data->min_volt_shift); mtk_cpufreq_voltage_tracking() will be called very frequently. retry_max is the same every time mtk_cpufreq_voltage_tracking() is called. Is it better to calculate before and store in mtk_cpu_dvfs_info? > > pre_vproc = regulator_get_voltage(proc_reg); > if (pre_vproc < 0) { > @@ -151,6 +161,12 @@ static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info, > > pre_vproc = vproc; > pre_vsram = vsram; > + > + if (--retry_max < 0) { > + dev_err(info->cpu_dev, > + "over loop count, failed to set voltage\n"); > + return -EINVAL; > + } > } while (vproc != new_vproc || vsram != new_vsram); > > return 0; > -- > 2.18.0 > 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DF3D9C433EF for ; Fri, 15 Apr 2022 06:33:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; 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Thu, 14 Apr 2022 23:15:00 -0700 (PDT) MIME-Version: 1.0 References: <20220415055916.28350-1-rex-bc.chen@mediatek.com> <20220415055916.28350-11-rex-bc.chen@mediatek.com> In-Reply-To: <20220415055916.28350-11-rex-bc.chen@mediatek.com> From: Hsin-Yi Wang Date: Fri, 15 Apr 2022 14:14:34 +0800 Message-ID: Subject: Re: [PATCH V3 10/15] cpufreq: mediatek: Add counter to prevent infinite loop when tracking voltage To: Rex-BC Chen Cc: rafael@kernel.org, Viresh Kumar , Rob Herring , krzk+dt@kernel.org, Matthias Brugger , Tim Chang , roger.lu@mediatek.com, Kevin Hilman , angelogioacchino.delregno@collabora.com, linux-pm@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, Project_Global_Chrome_Upstream_Group@mediatek.com X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220414_231502_549066_E940F5B3 X-CRM114-Status: GOOD ( 20.21 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org On Fri, Apr 15, 2022 at 1:59 PM Rex-BC Chen wrote: > > To prevent infinite loop when tracking voltage, we calculate the maximum > value for each platform data. > We assume min voltage is 0 and tracking target voltage using > min_volt_shift for each iteration. > The retry_max is 3 times of expeted iteration count. > > Signed-off-by: Rex-BC Chen > --- > drivers/cpufreq/mediatek-cpufreq.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c > index cc44a7a9427a..d4c00237e862 100644 > --- a/drivers/cpufreq/mediatek-cpufreq.c > +++ b/drivers/cpufreq/mediatek-cpufreq.c > @@ -86,6 +86,16 @@ static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info, > struct regulator *proc_reg = info->proc_reg; > struct regulator *sram_reg = info->sram_reg; > int pre_vproc, pre_vsram, new_vsram, vsram, vproc, ret; > + int retry_max; > + > + /* > + * We assume min voltage is 0 and tracking target voltage using > + * min_volt_shift for each iteration. > + * The retry_max is 3 times of expeted iteration count. > + */ > + retry_max = 3 * DIV_ROUND_UP(max(info->soc_data->sram_max_volt, > + info->soc_data->proc_max_volt), > + info->soc_data->min_volt_shift); mtk_cpufreq_voltage_tracking() will be called very frequently. retry_max is the same every time mtk_cpufreq_voltage_tracking() is called. Is it better to calculate before and store in mtk_cpu_dvfs_info? > > pre_vproc = regulator_get_voltage(proc_reg); > if (pre_vproc < 0) { > @@ -151,6 +161,12 @@ static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info, > > pre_vproc = vproc; > pre_vsram = vsram; > + > + if (--retry_max < 0) { > + dev_err(info->cpu_dev, > + "over loop count, failed to set voltage\n"); > + return -EINVAL; > + } > } while (vproc != new_vproc || vsram != new_vsram); > > return 0; > -- > 2.18.0 > _______________________________________________ Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id EB610C433EF for ; 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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Apr 15, 2022 at 1:59 PM Rex-BC Chen wrote: > > To prevent infinite loop when tracking voltage, we calculate the maximum > value for each platform data. > We assume min voltage is 0 and tracking target voltage using > min_volt_shift for each iteration. > The retry_max is 3 times of expeted iteration count. > > Signed-off-by: Rex-BC Chen > --- > drivers/cpufreq/mediatek-cpufreq.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c > index cc44a7a9427a..d4c00237e862 100644 > --- a/drivers/cpufreq/mediatek-cpufreq.c > +++ b/drivers/cpufreq/mediatek-cpufreq.c > @@ -86,6 +86,16 @@ static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info, > struct regulator *proc_reg = info->proc_reg; > struct regulator *sram_reg = info->sram_reg; > int pre_vproc, pre_vsram, new_vsram, vsram, vproc, ret; > + int retry_max; > + > + /* > + * We assume min voltage is 0 and tracking target voltage using > + * min_volt_shift for each iteration. > + * The retry_max is 3 times of expeted iteration count. > + */ > + retry_max = 3 * DIV_ROUND_UP(max(info->soc_data->sram_max_volt, > + info->soc_data->proc_max_volt), > + info->soc_data->min_volt_shift); mtk_cpufreq_voltage_tracking() will be called very frequently. retry_max is the same every time mtk_cpufreq_voltage_tracking() is called. Is it better to calculate before and store in mtk_cpu_dvfs_info? > > pre_vproc = regulator_get_voltage(proc_reg); > if (pre_vproc < 0) { > @@ -151,6 +161,12 @@ static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info, > > pre_vproc = vproc; > pre_vsram = vsram; > + > + if (--retry_max < 0) { > + dev_err(info->cpu_dev, > + "over loop count, failed to set voltage\n"); > + return -EINVAL; > + } > } while (vproc != new_vproc || vsram != new_vsram); > > return 0; > -- > 2.18.0 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel