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 X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B2074C54E4A for ; Mon, 11 May 2020 14:13:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9D2F5206DB for ; Mon, 11 May 2020 14:13:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730458AbgEKONX (ORCPT ); Mon, 11 May 2020 10:13:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37030 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1730158AbgEKONX (ORCPT ); Mon, 11 May 2020 10:13:23 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2B904C061A0C for ; Mon, 11 May 2020 07:13:23 -0700 (PDT) Received: from dude.hi.pengutronix.de ([2001:67c:670:100:1d::7]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jY9BC-0003lJ-88; Mon, 11 May 2020 16:13:14 +0200 Received: from ore by dude.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1jY9B8-0001LY-Ts; Mon, 11 May 2020 16:13:10 +0200 Date: Mon, 11 May 2020 16:13:10 +0200 From: Oleksij Rempel To: Andrew Lunn , "David S. Miller" , Florian Fainelli , Heiner Kallweit , Jakub Kicinski , Jonathan Corbet , Michal Kubecek Cc: David Jander , kernel@pengutronix.de, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Russell King , mkl@pengutronix.de, Marek Vasut , Christian Herber Subject: signal quality and cable diagnostic Message-ID: <20200511141310.GA2543@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 15:31:16 up 243 days, 2:19, 514 users, load average: 0.45, 0.37, 0.66 User-Agent: Mutt/1.10.1 (2018-07-13) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::7 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Andrew, First of all, great work! As your cable diagnostic patches are in net-next now and can be used as base for the follow-up discussion. Do you already have ethtool patches somewhere? :=) Can you please give a link for testing? I continue to work on TJA11xx PHY and need to export some additional cable diagnostic/link stability information: Signal Quality Index (SQI). The PHY data sheet describes it as following [1]: ================================================================================ 6.10.3 Link stability The signal-to-noise ratio is the parameter used to estimate link stability. The PMA Receive function monitors the signal-to-noise ratio continuously. Once the signal-to-noise ratio falls below a configurable threshold (SQI_FAILLIMIT), the link status is set to FAIL and communication is interrupted. The TJA1100 allows for adjusting the sensitivity of the PMA Receive function by configuring this threshold. The microcontroller can always check the current value of the signal-to-noise ratio via the SMI, allowing it to track a possible degradation in link stability. ================================================================================ Since this functionality is present at least on TJA11xx PHYs and mandatory according to Open Alliance[2], I hope this functionality is present on other 100/1000Base-T1 PHYs. So may be some common abstraction is possible. What would be the best place to provide it for the user space? According to the [2] SQI, is the part of Dynamic Channel Quality (DCQ) together with Mean Square Error (MSE) and Peak MSE value (pMSE). [1] https://www.nxp.com/docs/en/data-sheet/TJA1100.pdf [2] http://www.opensig.org/download/document/218/Advanced_PHY_features_for_automotive_Ethernet_V1.0.pdf http://www.opensig.org/download/document/225/Open_Alliance_100BASE-T1_PMA_Test_Suite_v1.0-dec.pdf -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |