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 18766C433FE for ; Tue, 8 Feb 2022 16:01:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1382621AbiBHQB4 (ORCPT ); Tue, 8 Feb 2022 11:01:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40524 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1382600AbiBHQBx (ORCPT ); Tue, 8 Feb 2022 11:01:53 -0500 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 32FFAC061579; Tue, 8 Feb 2022 08:01:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=G8d9XT4bl8XpGnnrhh9W2ll+8LVIFjC7omdTT8KDyIw=; b=G06wp3ldf/2hq5KaIhgCznyxLr 1eRODIqoka8a2jjEzzdrjYQY5znwjc5jZRk7brORqM/DIJT7mEGrUpWxmajkB6XEnOzWDLpH4qlQW 1tlGGk00JLv/rSimj+ga93WaVgc49AMYhbj+IklQTribY1unrBotumNR0HLq9Vgxn2bFguXDWx8Ki DyCoBY6Uq84DxYeP77yrwjVO+uoA91bVVcn1sHlVlpKbMWfJCwvixfl32xZqEBzKSS4IE4dHD6cXl 7H+5UaQT56S/BwuUuCdyPH/cc5BIwbeCTxgYuboMlbxsEKcXFWM+PJpyWgVOrWNDtPl/wId7f7g+o PFHD/qog==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:57158) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1nHSw6-0003OK-TH; Tue, 08 Feb 2022 16:01:46 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1nHSw5-0000gN-C5; Tue, 08 Feb 2022 16:01:45 +0000 Date: Tue, 8 Feb 2022 16:01:45 +0000 From: "Russell King (Oracle)" To: Raag Jadav Cc: Andrew Lunn , Heiner Kallweit , "David S. Miller" , Jakub Kicinski , Steen Hegelund , Bjarni Jonasson , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] net: phy: mscc: enable MAC SerDes autonegotiation Message-ID: References: <1644043492-31307-1-git-send-email-raagjadav@gmail.com> <20220206171234.GA5778@localhost> <20220207174948.GA5183@localhost> <20220208155752.GB3003@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220208155752.GB3003@localhost> Sender: Russell King (Oracle) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 08, 2022 at 09:27:52PM +0530, Raag Jadav wrote: > On Tue, Feb 08, 2022 at 03:09:48AM +0100, Andrew Lunn wrote: > > > MAC implementation[1] in a lot of NXP SoCs comes with in-band aneg enabled > > > by default, and it does expect Clause 37 auto-negotiation to complete > > > between MAC and PHY before the actual data transfer happens. > > > > > > [1] https://community.nxp.com/pwmxy87654/attachments/pwmxy87654/t-series/3241/1/AN3869(1).pdf > > > > > > I faced such issue while integrating VSC85xx PHY > > > with one of the recent NXP SoC having similar MAC implementation. > > > Not sure if this is a problem on MAC side or PHY side, > > > But having Clause 37 support should help in most cases I believe. > > > > So please use this information in the commit message. > > > > The only danger with this change is, is the PHY O.K with auto-neg > > turned on, with a MAC which does not actually perform auto-neg? It > > could be we have boards which work now because PHY autoneg is turned > > off. > > > > Introducing an optional device tree property could be of any help? Preferably not. We do need some way that the MAC and PHY can co-operate to work out whether inband should be used or not. Vladimir had some patches for that a while back which were touching phylib and phylink which may be worth looking into to see whether some of that can be applied to your situation. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!