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 C42A7C677F1 for ; Mon, 16 Jan 2023 13:04:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229695AbjAPNE0 (ORCPT ); Mon, 16 Jan 2023 08:04:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52938 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231517AbjAPNDe (ORCPT ); Mon, 16 Jan 2023 08:03:34 -0500 Received: from mail-ed1-x52a.google.com (mail-ed1-x52a.google.com [IPv6:2a00:1450:4864:20::52a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 76AD41449E; Mon, 16 Jan 2023 05:02:48 -0800 (PST) Received: by mail-ed1-x52a.google.com with SMTP id v10so39413146edi.8; Mon, 16 Jan 2023 05:02:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=DLfqfcaXi73VjYgQd4tjQ0KyH4dC5dOIZrX7XcLcA0g=; b=IfiUMchw8k9k8y7ay2ZB1xaHl/waySQNiTj8vQ1C7L9PsKb3YqbK2roDszZss0jZjm aUTuCnwZWymg9+ghh3Pk+VrNFgSvoRg7gDH6KRDU9XVFgQTkuvKPPx9Y6jPBReS1laEQ 9d5XjhZYJNTGqAj1v9CAbN5QCQAySN1uayGUUuVRqmiMrWnhO6+F/qokjii+eacnuS0m ohH1Lc1UzNsrj8QA+JHc7i07NUvVERRAST/mTNb8tRmx244aUFPk3J6IVcxP+ZMxf/Qg P//4IQ7Dl9I4qJrdGoK4ul5OAMhRdEzSKnlChFXS/YkM4dsj9suawspz6QUtlaR86Qvt 4osQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=DLfqfcaXi73VjYgQd4tjQ0KyH4dC5dOIZrX7XcLcA0g=; b=g9azNW6KKj75y3NkonU/L67HxafEqvbyzQOMAyhXKPaofZYMlbFdhQ27Q6S7PYDxix fhpriKP+QRsjFyust7pTSpF1ydvSFCqxfH6STF1u/D6c5I/oZZi+EWEBJ/h2sZHRLQtC p6/q4qPci6b9XvL56j6kuJ46X5guliTLsZRqE7T5avvc1WEoQ6fG2q68Bf3knfk2KVcD S8DYqApXEdKu+ZZ4AGD6W6bRExT2pU8f8R2lPIjArcgcPbXjv9F/ZEOWZOgGRF8ZYite Rs9sQd7MkPBJH/MqDH/IE3G2t8OXTABVfg7e73m0VRryPOUV7l/ewUKtO2YDkagQsulr O3yA== X-Gm-Message-State: AFqh2koHVgESED0Oez1ii1hd7nvT8u4wTNRgFC3dTEZeQWl/qGIYlrCH wo/zz8It1bhW8NQMUVK8kaY= X-Google-Smtp-Source: AMrXdXuhsVZtvI6rPoBrZ1WlOwVKZWCqvSltMxN/FmJe1tkmeH5ViGG3NZP7SVrPFy8uJYV/isPzSw== X-Received: by 2002:aa7:c04f:0:b0:499:376e:6b31 with SMTP id k15-20020aa7c04f000000b00499376e6b31mr27826579edo.29.1673874166602; Mon, 16 Jan 2023 05:02:46 -0800 (PST) Received: from skbuf ([188.27.185.68]) by smtp.gmail.com with ESMTPSA id r24-20020aa7da18000000b004704658abebsm11535997eds.54.2023.01.16.05.02.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 Jan 2023 05:02:46 -0800 (PST) Date: Mon, 16 Jan 2023 15:02:43 +0200 From: Vladimir Oltean To: nikhil.gupta@nxp.com Cc: linux-arm-kernel@lists.infradead.org, Yangbo Lu , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, vakul.garg@nxp.com, rajan.gupta@nxp.com, richardcochran@gmail.com Subject: Re: [PATCH v1] ptp_qoriq: fix latency in ptp_qoriq_adjtime() operation. Message-ID: <20230116130243.ghtythag3og6745y@skbuf> References: <20230116102440.27189-1-nikhil.gupta@nxp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230116102440.27189-1-nikhil.gupta@nxp.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi Nikhil, On Mon, Jan 16, 2023 at 03:54:40PM +0530, nikhil.gupta@nxp.com wrote: > From: Nikhil Gupta > > 1588 driver loses about 1us in adjtime operation at PTP slave. > This is because adjtime operation uses a slow non-atomic tmr_cnt_read() > followed by tmr_cnt_write() operation. > In the above sequence, since the timer counter operation keeps > incrementing, it leads to latency. > The tmr_offset register (which is added to TMR_CNT_H/L register > gives the current time) must be programmed with the delta > nanoseconds. > > Signed-off-by: Nikhil Gupta > Reviewed-by: Yangbo Lu > --- Your patch breaks eTSEC1 [ and eTSEC2 ] on LS1021A. Before: root@black:~# ip link set eth1 up root@black:~# [ 54.321664] fsl-gianfar soc:ethernet@2d50000 eth1: Link is Up - 1Gbps/Full - flow control off [ 54.331331] IPv6: ADDRCONF(NETDEV_CHANGE): eth1: link becomes ready root@black:~# ptp4l -i eth1 -2 -P -m ptp4l[57.231]: selected /dev/ptp0 as PTP clock ptp4l[57.351]: port 1: INITIALIZING to LISTENING on INIT_COMPLETE ptp4l[57.353]: port 0: INITIALIZING to LISTENING on INIT_COMPLETE ptp4l[57.355]: port 1: link down ptp4l[57.356]: port 1: LISTENING to FAULTY on FAULT_DETECTED (FT_UNSPECIFIED) ptp4l[57.455]: selected local clock 001f7b.fffe.630228 as best master ptp4l[57.458]: port 1: assuming the grand master role ptp4l[57.464]: selected local clock 001f7b.fffe.630228 as best master ptp4l[57.466]: port 1: assuming the grand master role [ 60.086366] fsl-gianfar soc:ethernet@2d50000 eth1: Link is Up - 1Gbps/Full - flow control off ptp4l[60.089]: port 1: link up ptp4l[60.183]: port 1: FAULTY to LISTENING on INIT_COMPLETE ptp4l[66.713]: port 1: LISTENING to MASTER on ANNOUNCE_RECEIPT_TIMEOUT_EXPIRES ptp4l[66.714]: selected local clock 001f7b.fffe.630228 as best master ptp4l[66.715]: port 1: assuming the grand master role ptp4l[102.753]: port 1: new foreign master 00049f.fffe.05f4ad-1 ptp4l[106.757]: selected best master clock 00049f.fffe.05f4ad ptp4l[106.758]: port 1: MASTER to UNCALIBRATED on RS_SLAVE ptp4l[107.763]: master offset -363290000824 s0 freq +0 path delay 735 ptp4l[108.764]: master offset -363289992530 s1 freq +8285 path delay 736 ptp4l[109.767]: master offset -1648 s2 freq +6637 path delay 736 ptp4l[109.768]: port 1: UNCALIBRATED to SLAVE on MASTER_CLOCK_SELECTED ptp4l[110.770]: master offset -6 s2 freq +7784 path delay 736 ptp4l[111.772]: master offset 491 s2 freq +8280 path delay 735 ptp4l[112.773]: master offset 495 s2 freq +8431 path delay 735 ptp4l[113.776]: master offset 342 s2 freq +8426 path delay 731 ptp4l[114.778]: master offset 198 s2 freq +8385 path delay 724 ptp4l[115.781]: master offset 100 s2 freq +8346 path delay 722 After: root@black:~# ip link set eth1 up root@black:~# [ 311.001924] fsl-gianfar soc:ethernet@2d50000 eth1: Link is Up - 1Gbps/Full - flow control off [ 311.013236] IPv6: ADDRCONF(NETDEV_CHANGE): eth1: link becomes ready root@black:~# ptp4l -i eth1 -2 -P -m ptp4l[333.797]: selected /dev/ptp0 as PTP clock ptp4l[333.916]: port 1: INITIALIZING to LISTENING on INIT_COMPLETE ptp4l[333.918]: port 0: INITIALIZING to LISTENING on INIT_COMPLETE ptp4l[333.919]: port 1: link down ptp4l[333.919]: port 1: LISTENING to FAULTY on FAULT_DETECTED (FT_UNSPECIFIED) ptp4l[334.012]: selected local clock 001f7b.fffe.630228 as best master ptp4l[334.013]: port 1: assuming the grand master role [ 336.626213] fsl-gianfar soc:ethernet@2d50000 eth1: Link is Up - 1Gbps/Full - flow control off ptp4l[336.631]: port 1: link up ptp4l[336.713]: port 1: FAULTY to LISTENING on INIT_COMPLETE ptp4l[343.832]: port 1: LISTENING to MASTER on ANNOUNCE_RECEIPT_TIMEOUT_EXPIRES ptp4l[343.833]: selected local clock 001f7b.fffe.630228 as best master ptp4l[343.834]: port 1: assuming the grand master role ptp4l[344.873]: port 1: new foreign master 00049f.fffe.05f4ad-1 ptp4l[348.879]: selected best master clock 00049f.fffe.05f4ad ptp4l[348.879]: port 1: MASTER to UNCALIBRATED on RS_SLAVE ptp4l[349.888]: master offset 215392521359 s0 freq +0 path delay 737 ptp4l[350.890]: master offset 215392529808 s1 freq +8433 path delay 738 ptp4l[351.896]: master offset 215392529845 s2 freq +32767999 path delay 735 ptp4l[351.896]: port 1: UNCALIBRATED to SLAVE on MASTER_CLOCK_SELECTED ptp4l[352.897]: master offset 215359819000 s2 freq +32767999 path delay 731 ptp4l[353.899]: master offset 215326980590 s2 freq +32767999 path delay 731 ptp4l[354.900]: master offset 215294167912 s2 freq +32767999 path delay 729 ptp4l[355.902]: master offset 215261357366 s2 freq +32767999 path delay 725 ptp4l[356.905]: master offset 215228532618 s2 freq +32767999 path delay -24741 ptp4l[357.907]: master offset 215195717627 s2 freq +32767999 path delay -51970 ptp4l[358.909]: master offset 215162898062 s2 freq +32767999 path delay -57014 ptp4l[359.912]: master offset 215130057602 s2 freq +32767999 path delay -59714 ptp4l[360.915]: master offset 215097182978 s2 freq +32767999 path delay -60737 ptp4l[361.917]: master offset 215064357344 s2 freq +32767999 path delay -60783 I have forwarded you an internal email which gives more details about how the 1588 block was integrated on the 3 eTSEC ports on LS1021A. The general takeaway is: please don't break that SoC, and NACK for this patch.