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 7B47BD0D791 for ; Fri, 11 Oct 2024 13:49:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=7NmmAxWcsO2sbmuPkS7qbP+mBMQQZwLpETCmDz7Tdvs=; b=RGQL9UsPM2lj+a28d9Jegh2hjA l7yf8VE0jsDzG22GAQT1UgrRCnl8CYg7p1ofxbeGTJ2dwnCoaDSq2DtFk81kwe/VwdUYBS+y5NAHx i6vtYdHSSmo371L9Hbil6MYlEmLoXhxEDNAHifAcdn4tRVRhdsEzoRgN51KQUHR3d16RcJHe6EDFa L97Mvl10RrQmGTbppRFZoE0F5mdzB/bWpxyDUZAVgsfLy3UiHQTAJDkXXdRvWW2mXzD421QiWHLln de6xWgE/mhrCM/hk647EzlBHJhBqCMeve0XbUfO8O388yXb9al70L2Yhq/Dy3CZKvg6Ua9RsnFmIt 28rGmUcQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1szG10-0000000GVog-38Mi; Fri, 11 Oct 2024 13:49:10 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1szFz7-0000000GVZV-3MQT for linux-arm-kernel@lists.infradead.org; Fri, 11 Oct 2024 13:47:16 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B45E2497; Fri, 11 Oct 2024 06:47:42 -0700 (PDT) Received: from pluto (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 82FF23F5A1; Fri, 11 Oct 2024 06:47:10 -0700 (PDT) Date: Fri, 11 Oct 2024 14:47:07 +0100 From: Cristian Marussi To: Florian Fainelli Cc: linux-arm-kernel@lists.infreadead.org, Rob Herring , Krzysztof Kozlowski , Conor Dooley , Sudeep Holla , Cristian Marussi , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , open list , "open list:SYSTEM CONTROL & POWER/MANAGEMENT INTERFACE" , "moderated list:SYSTEM CONTROL & POWER/MANAGEMENT INTERFACE" , justin.chen@broadcom.com, opendmb@gmail.com, kapil.hali@broadcom.com, bcm-kernel-feedback-list@broadcom.com, Arnd Bergmann Subject: Re: [PATCH v2] firmware: arm_scmi: Give SMC transport precedence over mailbox Message-ID: References: <20241007235413.507860-1-florian.fainelli@broadcom.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241007235413.507860-1-florian.fainelli@broadcom.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241011_064713_908644_F99C26E8 X-CRM114-Status: GOOD ( 15.62 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Oct 07, 2024 at 04:54:13PM -0700, Florian Fainelli wrote: > Broadcom STB platforms have for historical reasons included both > "arm,scmi-smc" and "arm,scmi" in their SCMI Device Tree node compatible > string, in that order. > > After the commit cited in the Fixes tag and with a kernel configuration > that enables both the SMC and the Mailbox transports, we would probe > the mailbox transport, but fail to complete since we would not have a > mailbox driver available. With each SCMI transport being a platform > driver with its own set of compatible strings to match, rather than an > unique platform driver entry point, we no longer match from most > specific to least specific. There is also no simple way for the mailbox > driver to return -ENODEV and let another platform driver attempt > probing. This leads to a platform with no SCMI provider, therefore all > drivers depending upon SCMI resources are put on deferred probe forever. > > By keeping the SMC transport objects linked first, we can let the > platform driver match the compatible string and probe successfully with > no adverse effects on platforms using the mailbox transport. > > Fixes: b53515fa177c ("firmware: arm_scmi: Make MBOX transport a standalone driver") > Signed-off-by: Florian Fainelli I was hoping to find some way to avoid this workaround.... ...but I failed :P ... so LGTM. Reviewed-by: Cristian Marussi Thanks, Cristian