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 X-Spam-Level: X-Spam-Status: No, score=-7.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2C5BAC433E9 for ; Fri, 12 Feb 2021 04:42:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D1E1464DAE for ; Fri, 12 Feb 2021 04:42:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229662AbhBLEmK (ORCPT ); Thu, 11 Feb 2021 23:42:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53380 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229562AbhBLEmH (ORCPT ); Thu, 11 Feb 2021 23:42:07 -0500 Received: from mail-pj1-x102c.google.com (mail-pj1-x102c.google.com [IPv6:2607:f8b0:4864:20::102c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D458DC0613D6 for ; Thu, 11 Feb 2021 20:41:26 -0800 (PST) Received: by mail-pj1-x102c.google.com with SMTP id lw17so5613669pjb.0 for ; Thu, 11 Feb 2021 20:41:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=3WNMt5XR+692WIpXHZivWGdM4xBg7M/kL8/oPyqVZG4=; b=qaQ5JWYqNNgsWrAMQwM8o2jl8EI0jJR2snb9qPJvnTXgING1a+YDGz4nusTevahy80 kWwJ8PR+3Xbj7JFAtYCUuqkzUUc12Y/7Pta24nOyz6mjnVappjZrdflJ3JuSm4bYIQOW w3FYTt1q83kY+ycLunbpsWg7ALI12ARzJcgferXPxk4uZ3euWCv1PPExNynfikwGKhiv MXEt0dgmQ1sAOktW+4niEDh8HTnY43T2cepdVJL1v7+atSnoexSzs98yz40ZSeThDsYr hcbjqWHeBSWXMS1uURtgLlrKaQ0dN3V36yQpSeQQGbIzqapNOylA7gm3ah6LiqEaozAP RZzQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=3WNMt5XR+692WIpXHZivWGdM4xBg7M/kL8/oPyqVZG4=; b=Ik1wl1qAeXTlupBzsNvxCLnY2D5gTkhJQqeFKZzA8jI+VgJp0a7V0qFRCs33APpA43 JI/5ZfmnUamXmEDHgMrNZjuBUIZH3laoBmMIfPk70ASa8YgTmEhwfUeUF8tTUjSI3Dfh 3f5Mx2AU7C/b6QSdRNjQqm1LSQKt9Ebt4kdEd4TGxmmKy3zpNLWaPz23uk/WaIjG0FQ4 2U7GXQz8LapXH9b8Q20k46bE9//Yp5sUahirgH0AikpWd7t1tfzL6NBcpU5mkJEgTEVd gLT0VkZd/k3x1VF0bkVVS7NesdVylhAGKwOKh2QmqfPMvt7RA7XradHtZJG98G1OJZB4 iTqg== X-Gm-Message-State: AOAM530uVIlxGoJWUsWxK3kd8vlgNEAsLYVtxnV9HLrLw1io3UYI6/RJ wEKnW4xDs8tSLbZhxpa8HBWRHQ== X-Google-Smtp-Source: ABdhPJyd9z/0E7cIiRh5X4uMlSbgcHzZSG/VIra3j3yOYbbXcYBEgVNzBzpdHejP7k0epZ2ItDg0Nw== X-Received: by 2002:a17:902:b094:b029:e3:a2f:4681 with SMTP id p20-20020a170902b094b02900e30a2f4681mr1370874plr.69.1613104886229; Thu, 11 Feb 2021 20:41:26 -0800 (PST) Received: from localhost ([122.172.59.240]) by smtp.gmail.com with ESMTPSA id h11sm7316176pfr.201.2021.02.11.20.41.24 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 11 Feb 2021 20:41:25 -0800 (PST) Date: Fri, 12 Feb 2021 10:11:23 +0530 From: Viresh Kumar To: Masahiro Yamada Cc: Rob Herring , Frank Rowand , Pantelis Antoniou , Michal Marek , Vincent Guittot , linux-arm-kernel , Linux Kernel Mailing List , Anmar Oueja , Bill Mills , David Gibson , DTML , Linux Kbuild mailing list , Geert Uytterhoeven , Michal Simek Subject: Re: [PATCH V7 1/3] kbuild: Add generic rule to apply fdtoverlay Message-ID: <20210212044123.7i6kzgekoddqufko@vireshk-i7> References: <44dad578df8a848fc378cd358f03b071f44c9a5b.1612955268.git.viresh.kumar@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180716-391-311a52 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12-02-21, 12:07, Masahiro Yamada wrote: > BTW, I do not know how to use overlay. > Do we apply overlay in the build time? Ideally it can be applied at both build time and runtime, but we haven't allowed the runtime way until now in kernel. This patchset is all about applying it at build time. > If so, I do not know what the benefit of overlay is. > Or is this just for build testing? For now the main benefit of using them is that we can keep stuff in separate files without including each other. For example a primary board may or may not have an extension board connected to it. Without overlays we will have this many dtbs for this simple case: 1. primary.dtb 2. extension.dtb 3. primary-includes-extension.dtb With overlays we will have the first two. Now the same extension can be applied to lots of boards and multiple extensions can be applied to the same primary board. This just complicates the process of managing dtbs. > I just thought this was done in the boot time, > for example, in U-Boot or something. Yes, bootloader can do it as well. -- viresh 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 X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 63C30C433DB for ; Fri, 12 Feb 2021 04:43:19 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0CA6A64E6B for ; Fri, 12 Feb 2021 04:43:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0CA6A64E6B Authentication-Results: mail.kernel.org; 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Thu, 11 Feb 2021 20:41:25 -0800 (PST) Date: Fri, 12 Feb 2021 10:11:23 +0530 From: Viresh Kumar To: Masahiro Yamada Subject: Re: [PATCH V7 1/3] kbuild: Add generic rule to apply fdtoverlay Message-ID: <20210212044123.7i6kzgekoddqufko@vireshk-i7> References: <44dad578df8a848fc378cd358f03b071f44c9a5b.1612955268.git.viresh.kumar@linaro.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180716-391-311a52 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210211_234128_800643_A8E33DF8 X-CRM114-Status: GOOD ( 18.23 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: DTML , Michal Marek , Vincent Guittot , Linux Kbuild mailing list , Bill Mills , Pantelis Antoniou , Linux Kernel Mailing List , Michal Simek , Anmar Oueja , Rob Herring , Geert Uytterhoeven , Frank Rowand , linux-arm-kernel , David Gibson Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 12-02-21, 12:07, Masahiro Yamada wrote: > BTW, I do not know how to use overlay. > Do we apply overlay in the build time? Ideally it can be applied at both build time and runtime, but we haven't allowed the runtime way until now in kernel. This patchset is all about applying it at build time. > If so, I do not know what the benefit of overlay is. > Or is this just for build testing? For now the main benefit of using them is that we can keep stuff in separate files without including each other. For example a primary board may or may not have an extension board connected to it. Without overlays we will have this many dtbs for this simple case: 1. primary.dtb 2. extension.dtb 3. primary-includes-extension.dtb With overlays we will have the first two. Now the same extension can be applied to lots of boards and multiple extensions can be applied to the same primary board. This just complicates the process of managing dtbs. > I just thought this was done in the boot time, > for example, in U-Boot or something. Yes, bootloader can do it as well. -- viresh _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel