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,URIBL_BLOCKED,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 92484C10F0E for ; Fri, 12 Apr 2019 09:55:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6A48021872 for ; Fri, 12 Apr 2019 09:55:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726860AbfDLJzj (ORCPT ); Fri, 12 Apr 2019 05:55:39 -0400 Received: from foss.arm.com ([217.140.101.70]:56754 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726713AbfDLJzi (ORCPT ); Fri, 12 Apr 2019 05:55:38 -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 45D0F15AB; Fri, 12 Apr 2019 02:55:38 -0700 (PDT) Received: from e107155-lin (e107155-lin.cambridge.arm.com [10.1.196.42]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id BDE343F59C; Fri, 12 Apr 2019 02:55:36 -0700 (PDT) Date: Fri, 12 Apr 2019 10:55:28 +0100 From: Sudeep Holla To: Aaro Koskinen Cc: "Koskinen, Aaro (Nokia - FI/Espoo)" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Florian Fainelli , Michal Simek , Mark Rutland , Lorenzo Pieralisi Subject: Re: [RESEND][PATCH v2] firmware/psci: add support for SYSTEM_RESET2 Message-ID: <20190412095528.GA12424@e107155-lin> References: <20190411103346.22462-1-sudeep.holla@arm.com> <20190411164936.GB5327@e107155-lin> <20190411182637.GC16745@darkstar.musicnaut.iki.fi> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190411182637.GC16745@darkstar.musicnaut.iki.fi> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 11, 2019 at 09:26:37PM +0300, Aaro Koskinen wrote: > Hi, > > On Thu, Apr 11, 2019 at 05:49:36PM +0100, Sudeep Holla wrote: > > On Thu, Apr 11, 2019 at 11:42:28AM +0000, Koskinen, Aaro (Nokia - FI/Espoo) wrote: > > > From: Sudeep Holla [sudeep.holla@arm.com]: > > > > static void psci_sys_reset(enum reboot_mode reboot_mode, const char *cmd) > > > > { > > > > + if ((reboot_mode == REBOOT_WARM || reboot_mode == REBOOT_SOFT) && > > > > > > I would omit the REBOOT_SOFT here. > > > > I included REBOOT_SOFT for 2 reasons: > > 1. drivers/firmware/efi/reboot.c - efi_reboot treats WARM and SOFT reboots same > > 2. If the vendors specific reboots are added and handled in EFI, I assume it > > will be categorised under REBOOT_SOFT. > > > > If that's wrong I can drop REBOOT_SOFT. > > Not a big issue, but it's just unclear what SOFT means. WARM at least maps > nicely to the PSCI spec. > OK, I will keep it for now. > > > > + psci_system_reset2_supported) > > > > + /* > > > > + * reset_type[31] = 0 (architectural) > > > > + * reset_type[30:0] = 0 (SYSTEM_WARM_RESET) > > > > + * cookie = 0 (ignored by the implementation) > > > > + */ > > > > + invoke_psci_fn(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2), 0, 0, 0); > > > > + > > > > invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0); > > > > > > Use else here, so that we fall back to system halt if SYSTEM_RESET2 fails. > > > > Will that not change current behaviour ? IOW, is that expected behaviour ? > > I am not sure if halt can be prefer over cold reboot in absence of warm/soft > > reboot when the system is request to reboot. From PSCI perspective, since > > SYSTEM_RESET is mandatory I prefer that unless Linux has any restriction > > on this behaviour. > > Hmm, so does it mean that even if firmware tells that SYSTEM_RESET2 > is implemented it does not imply that SYSTEM_WARM_RESET is > available? I.e. the firmware could choose to implement only some > vendor-specific resets but not architectural ones. In that case, could > we fall back to cold reset only if NOT_SUPPORTED is returned? My point > is that if the warm reset fails unexpectedly, we should halt the system > like we do if the cold reset fails. > OK, I understood. Sorry I was under the assumption that architectural reset was mandatory if SYSTEM_RESET2 is implemented. I checked the PSCI specification and I am wrong. So I am happy to add else as per your suggestion. -- Regards, Sudeep