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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 35665C28CF6 for ; Wed, 1 Aug 2018 09:10:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E19AD20840 for ; Wed, 1 Aug 2018 09:10:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E19AD20840 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388892AbeHAKzL (ORCPT ); Wed, 1 Aug 2018 06:55:11 -0400 Received: from foss.arm.com ([217.140.101.70]:37958 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387658AbeHAKzL (ORCPT ); Wed, 1 Aug 2018 06:55:11 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E3D1418A; Wed, 1 Aug 2018 02:10:25 -0700 (PDT) Received: from edgewater-inn.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id B4F423F5B3; Wed, 1 Aug 2018 02:10:25 -0700 (PDT) Received: by edgewater-inn.cambridge.arm.com (Postfix, from userid 1000) id DC8F01AE3096; Wed, 1 Aug 2018 10:10:27 +0100 (BST) Date: Wed, 1 Aug 2018 10:10:27 +0100 From: Will Deacon To: Alex Bounine Cc: Alexei Colin , Catalin Marinas , Andrew Morton , Russell King , John Paul Walters , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 6/6] arm64: enable RapidIO menu in Kconfig Message-ID: <20180801091027.GC14438@arm.com> References: <20180730225035.28365-1-acolin@isi.edu> <20180730225035.28365-7-acolin@isi.edu> <20180731084143.GA4680@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 31, 2018 at 04:29:56PM -0400, Alex Bounine wrote: > On 2018-07-31 08:54 AM, Alex Bounine wrote: > >On 2018-07-31 04:41 AM, Will Deacon wrote: > >>On Mon, Jul 30, 2018 at 06:50:34PM -0400, Alexei Colin wrote: > >>>Platforms with a PCI bus will be offered the RapidIO menu since they may > >>>be want support for a RapidIO PCI device. Platforms without a PCI bus > >>>that might include a RapidIO IP block will need to "select HAS_RAPIDIO" > >>>in the platform-/machine-specific "config ARCH_*" Kconfig entry. > >>> > >>>Tested that kernel builds for arm64 with RapidIO subsystem and > >>>switch drivers enabled, also that the modules load successfully > >>>on a custom Aarch64 Qemu model. > >>> > >>>Cc: Andrew Morton > >>>Cc: Russell King > >>>Cc: John Paul Walters > >>>Cc: linux-arm-kernel@lists.infradead.org > >>>Cc: linux-kernel@vger.kernel.org, > >>>Signed-off-by: Alexei Colin > >>>--- > >>>  arch/arm64/Kconfig | 2 ++ > >>>  1 file changed, 2 insertions(+) > >> > >>Thanks, this looks much cleaner than before: > >> > >>Acked-by: Will Deacon > >> > >>The only thing I'm not sure about is why we don't just select HAS_RAPIDIO > >>unconditionally in the arm64 Kconfig. Does selecting only that option > >>actually pull in new code to the build? > >> > >HAS_RAPIDIO option is intended for SOCs that have built in SRIO > >controllers, like TI KeyStoneII or FPGAs. Because RapidIO subsystem core > >is required during RapidIO port driver initialization, having separate > >option allows us to control available build options for RapidIO core and > >port driver (bool vs. tristate) and disable module option if port driver > >is configured as built-in. > > I am thinking about where HAS_RAPIDIO option can be set for arm64 branch. > Having it set globally is too broad. For example we have Xilinx Zinq US > board with SRIO IP on it. Having it globally in arm64 branch - bad. Probably > having it set in drivers/soc/... is the best place. Why is selecting HAS_RAPIDIO globally a bad thing to do? The way these normally work is, if some subsystem requires arch support, then there's an ARCH_HAS_xxxx option which the architecture selects when it implements that support. Once you've enabled that, then that allows other sub-options to be selected, such as specific drivers or what-not. Look at the Kconfig files under drivers/soc/ -- you don't see anybody selecting ARCH_HAS_* options. Now, if HAS_RAPIDIO alone is pulling in a whole load of code to the build, then it sounds like a misnomer. Confused. Will