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 075D5CCA473 for ; Fri, 22 Jul 2022 14:22:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231304AbiGVOV7 (ORCPT ); Fri, 22 Jul 2022 10:21:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53580 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229959AbiGVOV7 (ORCPT ); Fri, 22 Jul 2022 10:21:59 -0400 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 1CCE56406; Fri, 22 Jul 2022 07:21:58 -0700 (PDT) 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=hLPlQqZjJSQKPGHb0YS9zkev/y0pH7c+d/jPKAb2GH0=; b=Eipa470pMb32q7EeATriUghX+/ KITuXZ9S4vCLTY46DmqjDyGpM7vOaTX373ELSkiENYVCUbx37ijqPkd2wE1e8eoZ/NXZn+FVtqsz4 5A2IXJfCRbSu4HpYZz1TJWAO/I1puYiooK+eEk4qyILtT2gAbRvdqAuK7BuODcMliMa/h6kELMlhy wIVeKCswUAQFHcWin+dBmP6pOsTdfWz2RcKi3eUrlLuied06chsOSAqrvqr18tEZk2V7nQqkCA3Ei o6d+sBhp7fmyprsdGAzuuaiZSBcNf0kpciA3v0JXXoXb2tvk2/APeeqctcks5LlC1MElSVoNmw11j u8LOPsqw==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:33510) 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 1oErYE-0006sX-48; Fri, 22 Jul 2022 13:14:38 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1oErY1-0005of-0U; Fri, 22 Jul 2022 13:14:25 +0100 Date: Fri, 22 Jul 2022 13:14:24 +0100 From: "Russell King (Oracle)" To: Vladimir Oltean Cc: Marek =?iso-8859-1?Q?Beh=FAn?= , Andrew Lunn , Heiner Kallweit , Alexandre Belloni , Alvin __ipraga , Andy Shevchenko , Claudiu Manoil , Daniel Scally , "David S. Miller" , DENG Qingfang , Eric Dumazet , Florian Fainelli , George McCollister , Greg Kroah-Hartman , Hauke Mehrtens , Heikki Krogerus , Jakub Kicinski , Kurt Kanzenbach , Landen Chao , Linus Walleij , linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, Matthias Brugger , netdev@vger.kernel.org, Paolo Abeni , "Rafael J. Wysocki" , Sakari Ailus , Sean Wang , UNGLinuxDriver@microchip.com, Vivien Didelot , Woojung Huh Subject: Re: [PATCH net-next 3/6] net: dsa: add support for retrieving the interface mode Message-ID: References: <20220721151533.3zomvnfogshk5ze3@skbuf> <20220721192145.1f327b2a@dellmb> <20220721192145.1f327b2a@dellmb> <20220721182216.z4vdaj4zfb6w3emo@skbuf> <20220721213645.57ne2jf7f6try4ec@skbuf> <20220722105238.qhfq5myqa4ixkvy4@skbuf> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: Russell King (Oracle) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Jul 22, 2022 at 12:44:17PM +0100, Russell King (Oracle) wrote: > Given that this managed property was introduced for mvneta, mvneta's > implementation of it is the best reference we have to work out what > the intentions of it were beyond the commit text. > > With in-band mode enabled, mvneta makes use of a fixed-link PHY, and > updates the fixed-link PHY with the status from its GMAC block (which > is the combined PCS+MAC). > > So, when in-band mode is specified, the results from SGMII or 1000base-X > negotiation are read from the MAC side of the link, pushed into the > fixed-PHY, which then are reflected back into the driver via the usual > phylib adjust_link(). ... and I should have said that this is exactly why in-band mode is treated as a fixed-link, even though it's nothing of the sort. It makes use of the infrastructure that was present at the time (fixed-phy) to implement this feature of reading the link status from the PCS/MAC end of the link. It may not have been the best design, but it's an evolved design based on the code that was available and what people thought at the time (and pre-dates my involvement with mvneta in mainline.) -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!