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=-2.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 8AA37C433DB for ; Tue, 23 Mar 2021 06:58:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 492D0619B9 for ; Tue, 23 Mar 2021 06:58:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229994AbhCWG5k (ORCPT ); Tue, 23 Mar 2021 02:57:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35744 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229670AbhCWG5G (ORCPT ); Tue, 23 Mar 2021 02:57:06 -0400 Received: from mail-wm1-x329.google.com (mail-wm1-x329.google.com [IPv6:2a00:1450:4864:20::329]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3D44FC061574 for ; Mon, 22 Mar 2021 23:57:06 -0700 (PDT) Received: by mail-wm1-x329.google.com with SMTP id t5-20020a1c77050000b029010e62cea9deso10203984wmi.0 for ; Mon, 22 Mar 2021 23:57:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=message-id:subject:from:to:cc:date:in-reply-to:references :user-agent:mime-version:content-transfer-encoding; bh=5ZMjc9VXo9ubTn31PzCPvTM8mI49yM+c9RTAVxtpnpw=; b=AfPaVGk8GV8XMUonuzx6QfTnVqBvCdBO9LvGBuguQraZRnkc6XnJ0Q95dIR7cFTVBc N8Ig+WftiCnBV4pq2NbzARBIJWtRwG5DG5z8AS0Kl3yHlXNtEzrvStjTyRIoWfUBLbm+ 7UjbjsMM4YztwLL63EjzVDLZ2Ltx+XF7bO6h5tfRXi+LFNZZsLcXrsPexN+By4bYJo88 whuPM2lHejNnbg/vyl5+kUxYUtlAW9/ZQu9jBis0pNRcyuG4OVwXYh10qXNxE7n0OB5v ZG2VmVXVpVaiyKeoYbyGLYUmSs6Dl0t1E5G+nMy1b2KR4vtxQpc1KXWnug9bMzFYL4X7 uX1w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:subject:from:to:cc:date:in-reply-to :references:user-agent:mime-version:content-transfer-encoding; bh=5ZMjc9VXo9ubTn31PzCPvTM8mI49yM+c9RTAVxtpnpw=; b=LFPuKAMX9soVKWLPDQJGW2lVz0/10+gMkXIDlQOXhbUBTrf50u9KEf+FE1oye9lDMb xDPU2pLT7ffDR9cSrlcrIYvgPSQnA1YECbVispGSY0ZKMNKuMBhJHjovi0GBVxkAf3f7 gWy388vgw/Dmcc/zkvuemKAB4/kqZjxGtZaeqTFyYkYtJv/xOZBvTVgi2bCxJCvpep2s j2ZjyjT2NRP4yPx/9RM9607Ebkgdb95WaWDylxnPlS5wdrinnczjaQ4Ry5vCAU8OPL/D Ifx4GXwBEUvIuBkC+TPNpSHgtucfwAiyLTDsm1nTVNTm9/F85xTQ4rRWXhzI2606fo41 wZiA== X-Gm-Message-State: AOAM530uDzrBuHnRPomGWwZ3K5Y/ASZ6T9DRl6kJMxoghn5gOunloTCi aXo1dBWMLIybBog/p3eg8dJ1QYTdp22b9g== X-Google-Smtp-Source: ABdhPJz3+iV4FIBX4EKi4hgYNJtSbL0JsqeV154oIhUtr38a2kux3bYq5RyP/AdQx3H88cipHuuNpQ== X-Received: by 2002:a05:600c:21d2:: with SMTP id x18mr1785482wmj.175.1616482624927; Mon, 22 Mar 2021 23:57:04 -0700 (PDT) Received: from [192.168.1.21] ([195.245.23.48]) by smtp.gmail.com with ESMTPSA id n6sm25776205wrw.63.2021.03.22.23.57.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Mar 2021 23:57:04 -0700 (PDT) Message-ID: <854f1b96be2e2bf3daa9b8f2d8d00560f11fdfd3.camel@gmail.com> Subject: Re: RFC Need advice on reworking gpio-ep93xx.c to DT support From: Alexander Sverdlin To: Arnd Bergmann Cc: "nikita.shubin@maquefel.me" , Hartley Sweeten , "linux-gpio@vger.kernel.org" , Linus Walleij , "bgolaszewski@baylibre.com" , Arnd Bergmann Date: Tue, 23 Mar 2021 07:57:03 +0100 In-Reply-To: References: <1042421616413081@mail.yandex.ru> <01b4dedd0f7efba749ebf598925886a6a69d5b41.camel@gmail.com> <36281616430257@mail.yandex.ru> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.38.4 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org Hello Arnd! On Mon, 2021-03-22 at 23:31 +0100, Arnd Bergmann wrote: > Unfortunately, building a multiplatform kernel makes the kernel image > somewhat larger because it includes the code for CONFIG_OF, though > it does not have the runtime overhead for the DT data structures that you > get when running a DT-enabled kernel. Enabling CONFIG_USE_OF > increased the ep93xx_defconfig build for me by 128KB, replacing > the private clk driver with CONFIG_COMMON_CLOCK (and no driver) > on top added another 50KB, and finally enabling multiplatform added > another 2KB. In total, that is 2.7% total bloat in just the kernel image This doesn't sound so bad as I expected. I still had no chance to figure out much bigger increase from 5.4 to 5.12 ;) >    text    data     bss     dec     hex filename > 5677321 1119704   90556 6887581 69189d build/tmp/vmlinux > 5782854 1143720   92188 7018762 6b190a build/tmp/vmlinux-use_of > 5830020 1153408   89396 7072824 6bec38 build/tmp/vmlinux-of+clk > 5829320 1153920   91308 7074548 6bf2f4 build/tmp/vmlinux-multi > > I also think at some point in the distant future we will require DT boot for > everything, but that probably comes after most ARMv4T and earlier machines > have fallen out of use. I'd like to get a feeling for how EP93xx fits in there, > can you say what memory configurations are widely deployed and how The systems I know have 32MB RAM and 16MB Flash (but only 2MB was reserved for compressed kernel back then). > long you expect them to receive kernel upgrades in the future? Are these > systems that will definitely get put out of use at a particular time (e.g. > mobile phone infrastructure for older networks or fixed-time support > contracts), or are these systems that you expect to keep patching until > the hardware dies? Yes, I expect them to work (and be patched) until they die and this may take another decade ;) -- Alexander Sverdlin.