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=-5.2 required=3.0 tests=BAYES_00, 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 D7F92C4727E for ; Tue, 22 Sep 2020 10:26:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 85EF6208A9 for ; Tue, 22 Sep 2020 10:26:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726552AbgIVK0L (ORCPT ); Tue, 22 Sep 2020 06:26:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:54058 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726454AbgIVK0L (ORCPT ); Tue, 22 Sep 2020 06:26:11 -0400 Received: from gaia (unknown [31.124.44.166]) (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 348FD2086A; Tue, 22 Sep 2020 10:26:08 +0000 (UTC) Date: Tue, 22 Sep 2020 11:26:05 +0100 From: Catalin Marinas To: Arnd Bergmann Cc: Manivannan Sadhasivam , Matheus Castello , Olof Johansson , Andreas =?iso-8859-1?Q?F=E4rber?= , Mark Rutland , Rob Herring , edgar.righi@lsitec.org.br, igor.lima@lsitec.org.br, Helen Koike , Linux ARM , DTML , "linux-kernel@vger.kernel.org" , linux-actions@lists.infradead.org, Will Deacon Subject: Re: [PATCH v7 4/4] arm64: dts: Add Caninos Loucos Labrador v3 Message-ID: <20200922102605.GE15643@gaia> References: <20200922024302.205062-1-matheus@castello.eng.br> <20200922024302.205062-5-matheus@castello.eng.br> <20200922061454.GA29035@Mani-XPS-13-9360> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 22, 2020 at 10:32:06AM +0200, Arnd Bergmann wrote: > On Tue, Sep 22, 2020 at 8:15 AM Manivannan Sadhasivam > wrote: > > On Mon, Sep 21, 2020 at 11:43:02PM -0300, Matheus Castello wrote: > > > + /* Labrador v3 firmware does not support PSCI */ > > > > Oops. This is unfortunate... I'm not sure if this is even acceptable for > > ARM64 machines. > > > > Let me add Olof and Arnd... > > Adding Catalin and Will for additional input as well, this is more their > area than ours. > > I don't think we have formalized this as a policy, but we clearly don't > want new boards to use the spin table hack. As there are other > boards using psci on the same chip, I don't think this is a > hardware bug. I fully agree, we shouldn't allow new boards to use the spin-table method unless EL3 is missing on the CPU implementation (not the case here; only the APM hardware has this issue). Unfortunately we missed another platform with A53, see commit bc66392d8258 ("arm64: dts: fsl: Add device tree for S32V234-EVB"). The kernel relies on firmware for other things (power management, errata workarounds), so an SMC calling convention compliant firmware is highly recommended. I also don't see why it would be that hard to add PSCI. Even if you don't port something like Trusted Firmware, U-Boot has basic support for PSCI. So from my perspective, NAK on this patch. I'm tempted to also modify smp_spin_table_cpu_init() to print a big warning and return an error if this is attempted on new platforms. IOW, we make it a policy from now on. -- Catalin