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=-4.0 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 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 A06E2C433E1 for ; Fri, 17 Jul 2020 13:21:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7E54A20717 for ; Fri, 17 Jul 2020 13:21:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594992073; bh=7S1J9y8itEN5wvEhbpYW+BZkO1zoG1KjirrP9G0+mZY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=Zq6OzmJub1GCPOcm2vDixU8qfEHuiKXTxNSsYTSI3F2a1CsuEwi+vRyl7s2p+H48R fpaqmPSeTgpmGvrzlyFovmfY1HYlc62Ho6o5hW5O8xAbjzfs8HNVo2V04ivlAxN6Di JmDKQQZjFwzkQctwQFIv5FZuZ57VpDHtsuxzw7dI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726873AbgGQNVM (ORCPT ); Fri, 17 Jul 2020 09:21:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:47942 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726090AbgGQNVL (ORCPT ); Fri, 17 Jul 2020 09:21:11 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9DD8F2064B; Fri, 17 Jul 2020 13:21:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594992071; bh=7S1J9y8itEN5wvEhbpYW+BZkO1zoG1KjirrP9G0+mZY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=yQngermH9mwpKC/FUGsAks4v6MfDXijifC+rDmR27Bt6uhDtFOYjJ2KSY5xs7PeLr RfxRmMNyPT6WW1A8tPdegeS76iTpyS6LyOD1PJPCiz7Jnu+WKTl78eVBCrY3ZKe49Z 0DU/8yLX/miSAt6IDhdsQd3CEUqZzadR49zfo1Nw= Date: Fri, 17 Jul 2020 15:21:01 +0200 From: Greg KH To: Geert Uytterhoeven Cc: Linus Walleij , Anson Huang , John Stultz , Russell King , Shawn Guo , Sascha Hauer , Sascha Hauer , Fabio Estevam , Catalin Marinas , Will Deacon , Bartosz Golaszewski , "oleksandr.suvorov@toradex.com" , Adam Ford , Andreas Kemnade , "hverkuil-cisco@xs4all.nl" , Bjorn Andersson , Leo Li , Vinod Koul , Linux ARM , "linux-kernel@vger.kernel.org" , "open list:GPIO SUBSYSTEM" , dl-linux-imx , Jon Corbet , Arnd Bergmann , Olof Johansson , Kevin Hilman Subject: Re: [PATCH 1/3] gpio: mxc: Support module build Message-ID: <20200717132101.GA2984939@kroah.com> References: <1594164323-14920-1-git-send-email-Anson.Huang@nxp.com> <20200717121436.GA2953399@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 17, 2020 at 02:27:43PM +0200, Geert Uytterhoeven wrote: > Hi Greg, > > On Fri, Jul 17, 2020 at 2:14 PM Greg KH wrote: > > Android is just finally pushing vendors to get their code upstream, > > which is a good thing to see. And building things as a module is an > > even better thing as now it is finally allowing arm64 systems to be > > built to support more than one specific hardware platform at runtime. > > Can you please stop spreading this FUD? For many many SoCs today, this is not true. Their drivers are required to be built in and will not work as modules, as we are seeing the patches try to fix. > As I said before, Arm64 kernels have supported more than one specific > hardware platform at runtime from the beginning of the arm64 port > (assumed the needed platform support has been enabled in the kernel > config, of course). > Even most arm32 kernels support this, since the introduction of the > CONFIG_ARCH_MULTIPLATFORM option. In fact every recently > introduced arm32 platform is usually v7, and must conform to this. > The sole exceptions are very old platforms, and the v4/v5/v6/v7 split > due to architectural issues (the latter still support clusters of > platforms in a single kernel). I think the confusion here is that this really does not work well, if at all, on most "high end" SoC chips due to the collection of different things all of the vendors ship to their customers. This is the work that is trying to be fixed up here. And look at the driver core work for many driver subsystems to be fixed up just to get a single kernel image to work on multiple platforms. Just because older ones did it, doesn't mean it actually works today :) thanks, greg k-h