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 372A81125866 for ; Wed, 11 Mar 2026 18:45:59 +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=XAu+BmUZJ7E3VDzrG0SngQJMH9WKusejc8OjrJ/RKM4=; b=HRk8zWhRLCPlmSHFWVJ+EILbtP agFgfFH5ZT0IwG+ShkYawxrAWELu4J+7vrdug7xlsDooNwvKruyzmtSzco14jKVWakGYQe9WRqyWz MwcggRSvwN0HP2D74cSkeqV3Yski7aJ/uJqdCZ/TpzmbAV+wA5Gq9VgOqX3BJW4Ddl8wlz/dBhtys eKAhAiBKfbV7iJOK9V0xde3oDcZDFlB9NyijP9HHCq+NEUwRBksKF80P1U97aEq6ifmNKnRTLt+lc GJG/pUIT2rI5j6o5JB33Mz9Go4BI5O/6o6KBYybMXPFpKEwT7f1FMgb+PmRtOCcP3/3IYPtu70bKw qpBXs+7A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w0OZ7-0000000CE0U-1JcG; Wed, 11 Mar 2026 18:45:53 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w0OZ5-0000000CDzi-2gZm for linux-arm-kernel@lists.infradead.org; Wed, 11 Mar 2026 18:45:52 +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 62FF61682; Wed, 11 Mar 2026 11:45:42 -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 CA51B3F73B; Wed, 11 Mar 2026 11:45:44 -0700 (PDT) Date: Wed, 11 Mar 2026 18:45:41 +0000 From: Cristian Marussi To: Geert Uytterhoeven Cc: Cristian Marussi , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, arm-scmi@vger.kernel.org, linux-clk@vger.kernel.org, linux-renesas-soc@vger.kernel.org, sudeep.holla@arm.com, philip.radford@arm.com, james.quinlan@broadcom.com, f.fainelli@gmail.com, vincent.guittot@linaro.org, etienne.carriere@foss.st.com, peng.fan@oss.nxp.com, michal.simek@amd.com, dan.carpenter@linaro.org, geert+renesas@glider.be, kuninori.morimoto.gx@renesas.com, marek.vasut+renesas@gmail.com Subject: Re: [PATCH v2 08/13] firmware: arm_scmi: Harden clock protocol initialization Message-ID: References: <20260310184030.3669330-1-cristian.marussi@arm.com> <20260310184030.3669330-9-cristian.marussi@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260311_114551_720673_A3BBC277 X-CRM114-Status: GOOD ( 19.44 ) 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 Wed, Mar 11, 2026 at 05:59:43PM +0100, Geert Uytterhoeven wrote: > Hi Cristian, > > On Tue, 10 Mar 2026 at 19:56, Cristian Marussi wrote: > > Add proper error handling on failure to enumerate clocks features or > > rates. > > > > Signed-off-by: Cristian Marussi Hi, > > Thanks for your patch! > > > --- a/drivers/firmware/arm_scmi/clock.c > > +++ b/drivers/firmware/arm_scmi/clock.c > > > @@ -1143,8 +1149,12 @@ static int scmi_clock_protocol_init(const struct scmi_protocol_handle *ph) > > for (clkid = 0; clkid < cinfo->num_clocks; clkid++) { > > cinfo->clkds[clkid].id = clkid; > > ret = scmi_clock_attributes_get(ph, clkid, cinfo); > > - if (!ret) > > - scmi_clock_describe_rates_get(ph, clkid, cinfo); > > + if (ret) > > + return ret; > > This change breaks R-Car X5H with SCP FW SDKv4.28.0, as some clocks > do not support the SCMI CLOCK_ATTRIBUTES command. > Before, these clocks were still instantiated, but were further unusable. > After, the whole clock driver fails to initialize, and no SCMI clocks > are available at all. ...and this is exactly what I feared while doing this sort of hardening :P So there are a few possible solutions (beside reverting this straight away) The easy fix would be instead change the above in a if (ret) continue; ...with a bit of annoying accompanying FW_BUG logs, of course, to cause future FW releases to fix this :D Another option could be leave it as it is, since indeed it is the correct enforced behaviour, being CLOCK_ATTRIBUTES a mandatory command, BUT add on top an ad-hoc SCMI quirk targeting the affected FW releases... This latter option, though, while enforcing the correct behaviour AND fixing your R-Car issue, leaves open the door for a number of possible failures of other unknowingly buggy Vendors similarly deployed firmwares... ...that could be solved with more quirks of course...but...worth it ? Thoughts ? Let's see also what @Sudeep thinks about this... Thanks for testing ! Cristian