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 3C4EDC433EF for ; Mon, 11 Apr 2022 11:35:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345809AbiDKLh1 (ORCPT ); Mon, 11 Apr 2022 07:37:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53642 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236405AbiDKLhY (ORCPT ); Mon, 11 Apr 2022 07:37:24 -0400 Received: from mailgw02.mediatek.com (unknown [210.61.82.184]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EBD1539D; Mon, 11 Apr 2022 04:35:08 -0700 (PDT) X-UUID: dbd08abc811945b1993f258b3e75863a-20220411 X-UUID: dbd08abc811945b1993f258b3e75863a-20220411 Received: from mtkexhb02.mediatek.inc [(172.21.101.103)] by mailgw02.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 1613410139; Mon, 11 Apr 2022 19:35:02 +0800 Received: from mtkexhb01.mediatek.inc (172.21.101.102) by mtkmbs10n1.mediatek.inc (172.21.101.34) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.2.792.15; Mon, 11 Apr 2022 19:35:01 +0800 Received: from mtkcas10.mediatek.inc (172.21.101.39) by mtkexhb01.mediatek.inc (172.21.101.102) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Mon, 11 Apr 2022 19:35:01 +0800 Received: from mtksdccf07 (172.21.84.99) by mtkcas10.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Mon, 11 Apr 2022 19:35:01 +0800 Message-ID: <096e5da55313bb064575af4e64915fecb839a248.camel@mediatek.com> Subject: Re: [PATCH V2 06/15] cpufreq: mediatek: Record previous target vproc value From: Rex-BC Chen To: AngeloGioacchino Del Regno , , , , CC: , , , , , , , , , , "Andrew-sh . Cheng" Date: Mon, 11 Apr 2022 19:35:00 +0800 In-Reply-To: <4cc24333-3985-5efe-cc5f-c7b8492f6c1e@collabora.com> References: <20220408045908.21671-1-rex-bc.chen@mediatek.com> <20220408045908.21671-7-rex-bc.chen@mediatek.com> <4cc24333-3985-5efe-cc5f-c7b8492f6c1e@collabora.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.2 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2022-04-08 at 15:36 +0200, AngeloGioacchino Del Regno wrote: > Il 08/04/22 06:58, Rex-BC Chen ha scritto: > > From: Jia-Wei Chang > > > > We found the buck voltage may not be exactly the same with what we > > set > > because CPU may share the same buck with other module. > > Therefore, we need to record the previous desired value instead of > > reading > > it from regulators. > > > > Signed-off-by: Andrew-sh.Cheng > > Signed-off-by: Jia-Wei Chang > > --- > > drivers/cpufreq/mediatek-cpufreq.c | 31 +++++++++++++++++++---- > > ------- > > 1 file changed, 20 insertions(+), 11 deletions(-) > > > > diff --git a/drivers/cpufreq/mediatek-cpufreq.c > > b/drivers/cpufreq/mediatek-cpufreq.c > > index dc4a87e68940..472f4de29e5f 100644 > > --- a/drivers/cpufreq/mediatek-cpufreq.c > > +++ b/drivers/cpufreq/mediatek-cpufreq.c > > @@ -40,6 +40,7 @@ struct mtk_cpu_dvfs_info { > > struct list_head list_head; > > int intermediate_voltage; > > bool need_voltage_tracking; > > + int old_vproc; > > }; > > > > static LIST_HEAD(dvfs_info_list); > > @@ -190,11 +191,17 @@ static int > > mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info, > > > > static int mtk_cpufreq_set_voltage(struct mtk_cpu_dvfs_info > > *info, int vproc) > > { > > + int ret; > > + > > if (info->need_voltage_tracking) > > - return mtk_cpufreq_voltage_tracking(info, vproc); > > + ret = mtk_cpufreq_voltage_tracking(info, vproc); > > else > > - return regulator_set_voltage(info->proc_reg, vproc, > > - vproc + VOLT_TOL); > > + ret = regulator_set_voltage(info->proc_reg, vproc, > > + MAX_VOLT_LIMIT); > > + if (!ret) > > + info->old_vproc = vproc; > > + > > + return ret; > > } > > > > static int mtk_cpufreq_set_target(struct cpufreq_policy *policy, > > @@ -211,15 +218,7 @@ static int mtk_cpufreq_set_target(struct > > cpufreq_policy *policy, > > > > inter_vproc = info->intermediate_voltage; > > > > - old_freq_hz = clk_get_rate(cpu_clk); > > - old_vproc = regulator_get_voltage(info->proc_reg); > > - if (old_vproc < 0) { > > - pr_err("%s: invalid Vproc value: %d\n", __func__, > > old_vproc); > > - return old_vproc; > > - } > > - > > freq_hz = freq_table[index].frequency * 1000; > > - > > opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_hz); > > if (IS_ERR(opp)) { > > pr_err("cpu%d: failed to find OPP for %ld\n", > > @@ -229,6 +228,16 @@ static int mtk_cpufreq_set_target(struct > > cpufreq_policy *policy, > > vproc = dev_pm_opp_get_voltage(opp); > > dev_pm_opp_put(opp); > > > > + old_freq_hz = clk_get_rate(cpu_clk); > > + old_vproc = info->old_vproc; > > + if (old_vproc == 0) > > + old_vproc = regulator_get_voltage(info->proc_reg); > > + if (old_vproc < 0) { > > + dev_err(cpu_dev, "%s: invalid Vproc value: %d\n", > > + __func__, old_vproc); > > + return old_vproc; > > + } > > From my understandment, if this fails once, it fails forever! > > info->old_vproc is set only if info->need_voltage_tracking is true, > and only > in mtk_cpufreq_set_voltage(): this function is called only after the > checks > that you've introduced there, and that's on previously stored values. > While this was fine in the previous version, because it was always > calling > regulator_get_voltage(), here it's not. > > I think that a good option here is to: > > old_vproc = info->old_vproc; > if (old_vproc <= 0) > old_vproc = regulator_get_voltage(info->proc_reg); > if (old_vproc < 0) { > dev_err and return > } > > ...or, if this is not applicable, we should still find another way to > not > let this driver to simply fail forever in case anything goes wrong. > > Regards, > Angelo Hello Angelo, Yes, your concern is right. I will add this in next version. if (old_vproc <= 0) old_vproc = regulator_get_voltage(info->proc_reg); if (old_vproc < 0) { dev_err and return } BRs, Rex