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 7F94DC43334 for ; Wed, 29 Jun 2022 09:43:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233041AbiF2Jno (ORCPT ); Wed, 29 Jun 2022 05:43:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56680 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231338AbiF2Jnm (ORCPT ); Wed, 29 Jun 2022 05:43:42 -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 0AE042C649 for ; Wed, 29 Jun 2022 02:43:42 -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=/0f0mtJY9AEVyG9cKutPtOpi9e0QBZowrNf+7r5nfHQ=; b=O9hU6gJ9Cm4QGif7+OHrsFDoK+ N/KBHkiZetFbU6fRkM9mVr+ZJDjpRl1uY4+K8BwYbSCtQa2aIlYQnOXYtLUXUoSLDVGiOmsMbyGYM FRUPpwwozk6IL/xCy5unJV3tFKyKdGjo7OYe1v0lXKOU8lXaW9HvrCo6b6thTguKKxq568CdAeetI d0nVHqbCcyJytKISetWwFzETW+gWwCV/BLQAAcG03nsqC4F9nYxpFG+jCGAunenoOikYbS3XNi7UE UlTQcM3HG4dId4ZLIa84KSbtddqTKDJ23OQvD0crkGcnKJDdAbwiTkLpdgGWHRUuWOOjXiYA7plM9 WzN3CBXw==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:33086) 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 1o6UEI-0002mF-Ue; Wed, 29 Jun 2022 10:43:26 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1o6UEF-0005ki-OW; Wed, 29 Jun 2022 10:43:23 +0100 Date: Wed, 29 Jun 2022 10:43:23 +0100 From: "Russell King (Oracle)" To: Andrew Lunn Cc: Heiner Kallweit , Alexandre Belloni , Alvin =?utf-8?Q?=C5=A0ipraga?= , Claudiu Manoil , "David S. Miller" , DENG Qingfang , Eric Dumazet , Florian Fainelli , George McCollister , Hauke Mehrtens , Jakub Kicinski , Kurt Kanzenbach , Landen Chao , Linus Walleij , linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, Marek =?iso-8859-1?Q?Beh=FAn?= , Matthias Brugger , netdev@vger.kernel.org, Paolo Abeni , Sean Wang , UNGLinuxDriver@microchip.com, Vivien Didelot , Vladimir Oltean , Woojung Huh Subject: Re: [PATCH RFC net-next 0/4] net: dsa: always use phylink Message-ID: References: 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 Wed, Jun 29, 2022 at 09:18:10AM +0200, Andrew Lunn wrote: > > I should point out that if a DSA port can be programmed in software to > > support both SGMII and 1000baseX, this will end up selecting SGMII > > irrespective of what the hardware was wire-strapped to and how it was > > initially configured. Do we believe that would be acceptable? > > I'm pretty sure the devel b board has 1000BaseX DSA links between its > two switches. Since both should end up SGMII that should be O.K. Would such a port have a programmable C_Mode, and would it specify that it supports both SGMII and 1000BaseX ? Without going through a lot of boards and documentation for every switch, I can't say. I don't think we can come to any conclusion on what the right way to deal with this actually is - we don't have enough information about how this is used across all the platforms we have. I think we can only try something, get it merged into net-next, and wait to see whether anyone complains. When we have a CPU or DSA port without a fixed-link, phy or sfp specified, I think we should: (a) use the phy-mode property if present, otherwise, (b,i) have the DSA driver return the interface mode that it wants to use for max speed for CPU and DSA ports. (b,ii) in the absence of the DSA driver returning a valid interface mode, we use the supported_interfaces to find an interface which gives the maximum speed (irrespective of duplex?) that falls within the mac capabilities. If all those fail, then things will break, and we will have to wait for people to report that breakage. Does this sound a sane approach, or does anyone have any other suggestions how to solve this? -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!