From patchwork Fri Apr 15 05:59:11 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?b?UmV4LUJDIENoZW4gKOmZs+afj+i+sCk=?= X-Patchwork-Id: 12814562 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 373D0C433FE for ; Fri, 15 Apr 2022 06:01:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:CC:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Fgk4JbV/i35WuSXpne0wZoCcaVDXza4D7cvNfwDxk5c=; b=kQek84iC79mlkR 7LNzbcq7mS1T2a1qNuEG28Ee56DdjM9DFmb8FVmaIac+duaRfQay6Uq0as4AgCddGg2aPKpDg2xJM 7n6ruMZTXlQKm+/YGiV9p3VNupC1yEA/aglweV8+ChdzTBQKVGyYdomc/H4JcbULAX0Lx2U8Zysj1 olNEYLont6yT9UxjJziD05Szk2oHvNTLfwzNFkn65EIJjNjonmc5EdVkwkW0IbakUFcDIUdXQr6lE /S931zqWcLm3AiQtlCWSQtzxMpoMCnzTyS8s7bSvzbg4bKzybVy0OJvAc6snptgtQUrwjpPbLs1Pw 9h32VfSUJwvTtgSfF4XA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nfEzt-008oA2-Qu; Fri, 15 Apr 2022 05:59:58 +0000 Received: from mailgw02.mediatek.com ([216.200.240.185]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nfEzP-008nsm-AK; Fri, 15 Apr 2022 05:59:28 +0000 X-UUID: d2a753dc4d0a4453a8f09059b6726fa5-20220414 X-UUID: d2a753dc4d0a4453a8f09059b6726fa5-20220414 Received: from mtkcas68.mediatek.inc [(172.29.94.19)] by mailgw02.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 1046645988; Thu, 14 Apr 2022 22:59:21 -0700 Received: from MTKMBS07N2.mediatek.inc (172.21.101.141) by MTKMBS62N2.mediatek.inc (172.29.193.42) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 14 Apr 2022 22:59:20 -0700 Received: from mtkcas11.mediatek.inc (172.21.101.40) by mtkmbs07n2.mediatek.inc (172.21.101.141) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 15 Apr 2022 13:59:19 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by mtkcas11.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Fri, 15 Apr 2022 13:59:19 +0800 From: Rex-BC Chen To: , , , , CC: , , , , , , , , , , , Rex-BC Chen Subject: [PATCH V3 10/15] cpufreq: mediatek: Add counter to prevent infinite loop when tracking voltage Date: Fri, 15 Apr 2022 13:59:11 +0800 Message-ID: <20220415055916.28350-11-rex-bc.chen@mediatek.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20220415055916.28350-1-rex-bc.chen@mediatek.com> References: <20220415055916.28350-1-rex-bc.chen@mediatek.com> MIME-Version: 1.0 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220414_225927_384465_A920F9E4 X-CRM114-Status: GOOD ( 11.75 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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); 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;