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 90F88C32772 for ; Thu, 18 Aug 2022 15:06:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344167AbiHRPGM (ORCPT ); Thu, 18 Aug 2022 11:06:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34090 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344144AbiHRPF5 (ORCPT ); Thu, 18 Aug 2022 11:05:57 -0400 Received: from ssl.serverraum.org (ssl.serverraum.org [176.9.125.105]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BC3D377554; Thu, 18 Aug 2022 08:05:55 -0700 (PDT) Received: from ssl.serverraum.org (web.serverraum.org [172.16.0.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ssl.serverraum.org (Postfix) with ESMTPSA id E47F922248; Thu, 18 Aug 2022 17:05:53 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=walle.cc; s=mail2016061301; t=1660835153; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=HiAnFI7kVMl6PXgrx9Z0nQjSTLDVTqf5Dg5Dp/xCy04=; b=Naxxk5zfgMsndAFJBEUHrYsp1llu3XuJV4ZWqdOLoYBgbT9o7K3IXapYC8ZEMnV+K9caT7 NmAg9mtlrKQNfsLF3W+d3hyXKI4T5YumGvkQyhPGV5YfJwFCSxA1uz1el28u3OjdR/bgmV 6e9WGMYSE76czWPDCE2RsNXGgThvKnc= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Thu, 18 Aug 2022 17:05:53 +0200 From: Michael Walle To: Vladimir Oltean Cc: devicetree@vger.kernel.org, netdev@vger.kernel.org, Shawn Guo , Leo Li , Rob Herring , Krzysztof Kozlowski , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH devicetree 0/3] NXP LS1028A DT changes for multiple switch CPU ports In-Reply-To: <20220818145556.ieg37btfny3o2i4q@skbuf> References: <20220818140519.2767771-1-vladimir.oltean@nxp.com> <8d3d96cdede2f1e40ed9ae5742a0468d@walle.cc> <20220818145556.ieg37btfny3o2i4q@skbuf> User-Agent: Roundcube Webmail/1.4.13 Message-ID: <04fb89b973011bf111795e1f17fac311@walle.cc> X-Sender: michael@walle.cc Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am 2022-08-18 16:55, schrieb Vladimir Oltean: > On Thu, Aug 18, 2022 at 04:49:49PM +0200, Michael Walle wrote: >> Is it used automatically or does the userspace has to configure >> something? > > DSA doesn't yet support multiple CPU ports, but even when it will, the > second DSA master still won't be used automatically. If you want more > details about the proposed UAPI to use the second CPU port, see here: > https://patchwork.kernel.org/project/netdevbpf/cover/20220523104256.3556016-1-olteanv@gmail.com/ > >> > Care has been taken that this change does not produce regressions when >> > using updated device trees with old kernels that do not support multiple >> > DSA CPU ports. The only difference for old kernels will be the >> > appearance of a new net device (for &enetc_port3) which will not be very >> > useful for much of anything. >> >> Mh, I don't understand. Does it now cause regressions or not? I mean >> besides that there is a new unused interface? > > It didn't cause regressions until kernel 5.13 when commit adb3dccf090b > ("net: dsa: felix: convert to the new .change_tag_protocol DSA API") > happened, then commit 00fa91bc9cc2 ("net: dsa: felix: fix tagging > protocol changes with multiple CPU ports") fixed that regression and > was > backported to the linux-5.15.y stable branch AFAIR. So at least kernels > 5.15 and newer should work properly with the new device trees. Thanks for the details! >> I was just thinking of that systemready stuff where the u-boot might >> supply its (newer) device tree to an older kernel, i.e. an older >> debian >> or similar. >> >> -michael > > Yeah, I hear you, I'm doing my best to make the driver work with a > one-size-fits-all device tree, both ways around. TBH I don't really care much, I was merely curious what to expect. -michael