From patchwork Fri Sep 1 07:36:40 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Devi Priya X-Patchwork-Id: 13372149 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 31C8BCA0FE6 for ; Fri, 1 Sep 2023 07:37:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245120AbjIAHhM (ORCPT ); Fri, 1 Sep 2023 03:37:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43736 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234471AbjIAHhL (ORCPT ); Fri, 1 Sep 2023 03:37:11 -0400 Received: from mx0a-0031df01.pphosted.com (mx0a-0031df01.pphosted.com [205.220.168.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5181410D2; Fri, 1 Sep 2023 00:37:08 -0700 (PDT) Received: from pps.filterd (m0279862.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 3815wRc6013405; Fri, 1 Sep 2023 07:36:59 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h=from : to : cc : subject : date : message-id : mime-version : content-type; s=qcppdkim1; bh=CKvBT38tHSqEYMIsnstJQ+NMjLwRjhLHwqunnq7Hwrw=; b=dJUHyCbL4uqlEbAl2+uwzaAdjO42eSiS+jEErBee1wphUy98hagXMCHV3T1qegvYWuC/ Oeoe4VyGnPS9NVsTt32HmKVzOQDonTqyN5eiK7rt8vP9lq8dkPxeyEZ4/pWLiKLP3it5 4f4W6tQHNNDcrHAcFQFVvbRHFuxVFXBP4ppfdBeWeSTBgDW3r38dsq5hrQOlPzk93gXL kdQgw3+oEaAwdxx2P1rVoSStn8/o6eFH/nP/kFNr80T4lsQ7AnwoFyVilrHfiSGyWziT j9gtn0aeDJys5svA5/0JPBnYkjhRRZTG0pig7XkZ0JINuK7mAsCMP/KsvPGLm8HwbB+w NQ== Received: from nalasppmta05.qualcomm.com (Global_NAT1.qualcomm.com [129.46.96.20]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3su89e8edb-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 01 Sep 2023 07:36:59 +0000 Received: from nalasex01a.na.qualcomm.com (nalasex01a.na.qualcomm.com [10.47.209.196]) by NALASPPMTA05.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 3817awft032413 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 1 Sep 2023 07:36:58 GMT Received: from devipriy-linux.qualcomm.com (10.80.80.8) by nalasex01a.na.qualcomm.com (10.47.209.196) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.36; Fri, 1 Sep 2023 00:36:54 -0700 From: Devi Priya To: , , , , , , , , CC: , Subject: [PATCH V2] clk: qcom: clk-rcg2: Fix clock rate overflow for high parent frequencies Date: Fri, 1 Sep 2023 13:06:40 +0530 Message-ID: <20230901073640.4973-1-quic_devipriy@quicinc.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01a.na.qualcomm.com (10.52.223.231) To nalasex01a.na.qualcomm.com (10.47.209.196) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-ORIG-GUID: 4Z3cnFO4cjXB8yxRsPz1NXuYH4RTN16n X-Proofpoint-GUID: 4Z3cnFO4cjXB8yxRsPz1NXuYH4RTN16n X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.267,Aquarius:18.0.957,Hydra:6.0.601,FMLib:17.11.176.26 definitions=2023-09-01_04,2023-08-31_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 spamscore=0 priorityscore=1501 adultscore=0 clxscore=1011 suspectscore=0 malwarescore=0 mlxscore=0 impostorscore=0 bulkscore=0 lowpriorityscore=0 mlxlogscore=953 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2308100000 definitions=main-2309010071 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org If the parent clock rate is greater than unsigned long max/2 then integer overflow happens when calculating the clock rate on 32-bit systems. As RCG2 uses half integer dividers, the clock rate is first being multiplied by 2 which will overflow the unsigned long max value. Hence, replace the common pattern of doing 64-bit multiplication and then a do_div() call with simpler mult_frac call. Fixes: bcd61c0f535a ("clk: qcom: Add support for root clock generators (RCGs)") Signed-off-by: Devi Priya Reviewed-by: Marijn Suijten --- Changes in V2: - Replaced 64-bit multiplication & a do_div call with mult_frac call as suggested by Marijn Suijten. - Updated the subject title - Added Fixes tag - Did not pick up the R-b tag due to the above changes. drivers/clk/qcom/clk-rcg2.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c index a42f661550ca..f64d69164547 100644 --- a/drivers/clk/qcom/clk-rcg2.c +++ b/drivers/clk/qcom/clk-rcg2.c @@ -159,15 +159,11 @@ static unsigned long calc_rate(unsigned long rate, u32 m, u32 n, u32 mode, u32 hid_div) { if (hid_div) { - rate *= 2; - rate /= hid_div + 1; + rate = mult_frac(rate, 2, hid_div + 1); } if (mode) { - u64 tmp = rate; - tmp *= m; - do_div(tmp, n); - rate = tmp; + rate = mult_frac(rate, m, n); } return rate;