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 C80DAC6FD1D for ; Mon, 20 Mar 2023 16:17:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230499AbjCTQRv (ORCPT ); Mon, 20 Mar 2023 12:17:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49086 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229952AbjCTQR1 (ORCPT ); Mon, 20 Mar 2023 12:17:27 -0400 Received: from mail-oa1-x36.google.com (mail-oa1-x36.google.com [IPv6:2001:4860:4864:20::36]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 086D930191; Mon, 20 Mar 2023 09:07:15 -0700 (PDT) Received: by mail-oa1-x36.google.com with SMTP id 586e51a60fabf-17ac5ee3f9cso13438324fac.12; Mon, 20 Mar 2023 09:07:15 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679328101; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=Ycdbh/3im0d0MXCRS+MVRgOfUwsMwW5wd9W+JCKfV/o=; b=E+Pr8u9gmHBQZTNZQpUc9GvmZnrdszR9iS+GmECWvFOGiFG58/sXvKMBj66J9oYgrF Ax3wqSdk2q7Gv/Ewv0qKdreErNrtDXfMenESWsR5yB1b+hmUtAtq7ypozTdq0kMv5mHb SoTrRSsxM7BigWl6S73GK8jB/+JZATNbTt0hyjitN9HaLeaV/UjKXIsru+WJMcYfI6Qt bfMEn87SzBcSPYrQXaTDGP4oZf+vJDHOE8zOnYHAlKgzFElKGkvJpsXWNc6SKg6g5Ptd hYmAl/3pF6eXUa4UKxtjHhAJyVX+oSRvnTbUjWfkX8LZ0Kc2wVFhmvvnoJyoeqoCAn+I tLxA== X-Gm-Message-State: AO0yUKVo/HF1Hy8w2GoV2jXcKIPAMujWIDZp7gTt9aC7TphY0Hcoqqxx L2qQfsN2L8uc33Qa1987vw== X-Google-Smtp-Source: AK7set+BBHYnuq6OwVL9kjgfa2qix8lcrHAvO1bkzPcA8ohY9QPJdfChG4+hLAEfhyzub/UAI84YdA== X-Received: by 2002:a05:6870:330a:b0:177:b026:3cda with SMTP id x10-20020a056870330a00b00177b0263cdamr5812793oae.37.1679328099533; Mon, 20 Mar 2023 09:01:39 -0700 (PDT) Received: from robh_at_kernel.org (66-90-144-107.dyn.grandenetworks.net. [66.90.144.107]) by smtp.gmail.com with ESMTPSA id tb7-20020a05687186c700b0017630fe87e5sm3404469oab.33.2023.03.20.09.01.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Mar 2023 09:01:39 -0700 (PDT) Received: (nullmailer pid 1764454 invoked by uid 1000); Mon, 20 Mar 2023 16:01:37 -0000 Date: Mon, 20 Mar 2023 11:01:37 -0500 From: Rob Herring To: Cristian Ciocaltea Cc: Conor Dooley , Krzysztof Kozlowski , Sudeep Holla , Cristian Marussi , Krzysztof Kozlowski , Greg Kroah-Hartman , Liam Girdwood , Mark Brown , Nicolas Frattaroli , Heiko Stuebner , Jaroslav Kysela , Takashi Iwai , Paul Walmsley , Palmer Dabbelt , Albert Ou , Daniel Drake , Katsuhiro Suzuki , linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, alsa-devel@alsa-project.org, linux-rockchip@lists.infradead.org, linux-riscv@lists.infradead.org, kernel@collabora.com Subject: Re: [PATCH 02/11] dt-bindings: serial: snps-dw-apb-uart: Relax dma-names order constraint Message-ID: <20230320160137.GB1755078-robh@kernel.org> References: <20230315114806.3819515-1-cristian.ciocaltea@collabora.com> <20230315114806.3819515-3-cristian.ciocaltea@collabora.com> <3679f2d0-55f0-1710-abc2-b268b6fc6969@linaro.org> <8ae57fe3-56aa-7e50-3eaa-a12a40657baf@collabora.com> <80796828-7b38-184a-2e8e-3cfe9158b67f@linaro.org> <13cb8dbd-994c-4b38-b715-44a3bf3d278d@spud> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 17, 2023 at 07:43:53PM +0200, Cristian Ciocaltea wrote: > On 3/17/23 18:26, Conor Dooley wrote: > > On Fri, Mar 17, 2023 at 04:54:47PM +0100, Krzysztof Kozlowski wrote: > > > On 17/03/2023 11:21, Cristian Ciocaltea wrote: > > > > On 3/17/23 10:31, Krzysztof Kozlowski wrote: > > > > > On 15/03/2023 12:47, Cristian Ciocaltea wrote: > > > > > > Commit 370f696e4474 ("dt-bindings: serial: snps-dw-apb-uart: add dma & > > > > > > dma-names properties") documented dma-names property to handle Allwiner > > > > > > D1 dtbs_check warnings, but relies on a strict rx->tx ordering, which is > > > > > > the reverse of what a different board expects: > > > > > > > > > > > > rk3326-odroid-go2.dtb: serial@ff030000: dma-names:0: 'rx' was expected > > > > > > > > > > > > A quick and incomplete check shows the inconsistency is present in many > > > > > > other DT files: > > > > > > > > > > Why not fixing the DTS? The properties should have fixed order. > > > > > > > > I was initially concerned about the risk of a potential ABI breakage, > > > > but I think that's not really a problem since dma-names is not directly > > > > accessed in the driver and DT Kernel API doesn't rely on a particular order. > > > > > > > > If there are no objections, I would switch the order in the binding to > > > > tx->rx, since that's what most of the DTS use, and fix the remaining ones. > > > > > > Since we added the order recently, I rather assume it is the correct or > > > preferred one. > > > > IIRC I checked around the other serial bindings & there was not a > > consistent order that all serial bindings used, so I picked the order that > > was used across the various allwinner boards that do use dma-names. > > Thanks for clarifying this, Conor! Would it be fine to switch to tx->rx > order as it requires less changes to fix the inconsistencies? > > > Before changing dts files, it's probably a good idea to make sure that > > the dma-names are not used somewhere outside of Linux. > > Right, that means we cannot exclude the ABI breakage concern. Not sure how > easy would be to actually verify this. Hence I wonder if there is really no > chance to allow the flexible order in the binding.. If it changes and someone complains, then yes we'll allow flexible order. Rob