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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 61A58C433EF for ; Tue, 12 Jul 2022 09:25:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Cc:To:Subject:Message-ID:Date:From: In-Reply-To:References:MIME-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=U2srVR1WEMyQ9WX9Xp+nLgQ0JmsCQl9XIi+xfstBCtQ=; b=lOSGotKBytuzmS ZHKolUIK0PIg0ednLqI3ie7J7HjliDIxxOcP0PdH5XOiEeUvvHHY3vQfZ1D/IamJgglpEJPPUq19O ff6TQoNVfpcpI+4D2K6XZ2AFxFAf3GDwAVuZYGjReFyhiGq7jwGToA5e4wYZdmFxUudWaHepa0OUK qcs9DYJ0npUAZ+uhdgPhVJ/wE4dhpKRNsJbuaGHQRk1BfdnEaF/RhOK9Cc8S/Xe1kO16MVg/wX98B ADodmE+vbZRBHSXR7QpoShCNnJvJcUMWeEIy+SqkBUYXi0xoTDNR23tvtxKzC4a7mG5A6DCujfX5M kvOk8aKMMjLRrlycYJ2Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oBC7b-009Crr-41; Tue, 12 Jul 2022 09:23:59 +0000 Received: from mout.kundenserver.de ([212.227.126.135]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oBC7X-009CoQ-Sl for linux-arm-kernel@lists.infradead.org; Tue, 12 Jul 2022 09:23:57 +0000 Received: from mail-yb1-f169.google.com ([209.85.219.169]) by mrelayeu.kundenserver.de (mreue010 [213.165.67.97]) with ESMTPSA (Nemesis) id 1Mq2za-1nppjC33ys-00n9OX for ; Tue, 12 Jul 2022 11:23:48 +0200 Received: by mail-yb1-f169.google.com with SMTP id h62so10305344ybb.11 for ; Tue, 12 Jul 2022 02:23:48 -0700 (PDT) X-Gm-Message-State: AJIora+EYcFwjF+4KZnupHuOHh+W9Z4a6mMWxOnAa+s+c4nz/x55qGcD r+seNIBkVr19RQJsuu34kJeESY7EOwWJ85j1C9Q= X-Google-Smtp-Source: AGRyM1vvu7IPuckfzKVSX5vEdFZWzi3D02Yak8s6zNNkpMlgrf2ASLos5nqMVbEvvfRf9d+/jAmONuNoP1P7k2unqa8= X-Received: by 2002:a25:7c41:0:b0:66d:766a:4815 with SMTP id x62-20020a257c41000000b0066d766a4815mr21431651ybc.480.1657617827417; Tue, 12 Jul 2022 02:23:47 -0700 (PDT) MIME-Version: 1.0 References: <20220630083641.21835-1-vladimir.murzin@arm.com> In-Reply-To: From: Arnd Bergmann Date: Tue, 12 Jul 2022 11:23:30 +0200 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [RFC PATCH 0/3] ARM: Support Cortex-R platform(s) To: Vladimir Murzin Cc: Linux ARM , Arnd Bergmann , Ayan Kumar Halder , Stefano Stabellini X-Provags-ID: V03:K1:rdHpWKlYW2iHBV0IsTX1WSY9gYKgXBmMUwQUu1VPYrdvI+bewDR 6LwoV5eAhH3Dhh7BSRVo3KLxE0ZxJucnuKps5s/QmJGKCfyrhmx3cKHXFFp0eubiI5iZiTz Wz16R84MThER5Mo2eBp7Czpx5ARhiNk8YgF0RlLFfXGILKqfecDWzvLmdp/W6MLIHUtYmZy aDib5zfx5TXAV7U/8MO+w== X-UI-Out-Filterresults: notjunk:1;V03:K0:QeBYWIDXOZY=:WAfs8UP7uzfu+UlvHSoXbQ /qL7wFhEGKaibEKP+A89HLTrEjCOypmKEMZQonaFmvayfONTz9apYsgSOUQFwzd7NTtnowR2V A8oPKOEnc1GFrMumaz3sh3SJ2Kxa1B6mbA3dytsk3y04dzJUXyrrmtwhimm/BFynSSuwtfyD0 qJIbPdWKDd5hfU3Wa4kFsyVR536G0sr9lUX3GtWOkwBzKpk3yVdCnxD27+oS+AWBRM62omHfU JS6vPn63c3gY4AvgJNEQHn5Xr8dYb1yml35fWRNBt+cOt74j5tAwomOeAnfJPmUH65nRH5Lm8 1CK5Pxlbrd2FCGgyy3hcqvgAtMSw8GKhl/SrfcUT16id1l21QCPG3GX92FovZ1Og2+l9Ox4Gn 0/IwgWvr2qvegX+nhreoa/dkGf3FW9lUNoQ0o1/I/u+BJo+5uJjLSB58kU7N3mpu3/KFHARyK TWaHeTASLrAA1vo6LxSN0hsmS/JEphyg1BKzkJWZFlcIXF9Ni77RykWVcDq0QIhxdjfDwzFZd f2GO2fdmB65+HE6Bdcp4m49OxBDPVmBxRSUZRt1zeB2IhiLG4IVn7XHFwxxJsAV4b98iJBkk4 OecDoUNfM1tUxBSzBHHEFowalIocszkHrJbJiSTM5OkgFCgVJlZfIU84KsAFzRO0I9HsRRh9T DbryL2hnYGjpKjGS047dTFTGvf6OlK9kF8BBcll4K9wQPJLEIJaLYq9X61n/6AppnnK6IM/sd Ds7czIHN8ZMeztNECLFXD+bWOaOEA6NzAwjxPQ== X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220712_022356_242104_2B162734 X-CRM114-Status: GOOD ( 22.17 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 Tue, Jul 12, 2022 at 10:33 AM Vladimir Murzin wrote: > On 6/30/22 09:36, Vladimir Murzin wrote: > > > > I've been running Linux on Cortex-R cores with downstream patches for > > several years already. There are few reasons why we have not got any > > real platform supporting Cortex-R cores so far: > > 1) lack of interest > > 2) lack of easily available platforms > > 3) missing Kconfig bits > > > > During these years I've been receiving questions (mostly in private) > > about running Linux with Cortex-R cores. Use cases vary, but mostly > > fall under "we know Linux and do not want yet another RTOS", also > > people not always care about real-time features of R-class cores and > > see it as an upgrade from M-class cores. > > > > Sometime ago MPS3 platform got support for FPGA image [1] with > > Cortex-R52 cores where Linux can live comfortably. > > > > This patchset addresses #3 and brings support for MPS3 platform > > featuring Cortex-R52 > > > > [1] https://developer.arm.com/downloads/-/download-fpga-images > > Anything I can do to make progress with the series or it falls under > "we do not care" category? I think at this point it's an actively bad idea to merge support for Cortex-R. I don't think anyone else cares, but if you can find other people that want this to get merged (and know what they are talking about), you can overrule me on this. The existing MPS2 support is important because it gives developers an easy way to test Cortex-M based NOMMU code, and we still have users on STM32 at least. I do expect the STM32 MCU user base to further shrink, to the point where nobody is updating their kernels any more and we want to remove not just STM32 but all other Cortex-M platforms. All others are already further down the road of decline and MPS2 is not useful by itself. Merging MPS3/Cortex-R52 now feels like a step in the wrong direction, if that leads to a future situation where we remove Cortex-M but keep Cortex-R support around. Arnd _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel