From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id DE24D38F64B; Thu, 12 Mar 2026 16:36:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773333419; cv=none; b=GrFJPvhcjuZDQbJ7bUPyJNwFB5AtQlTpjUaqFrIYP3pOtWMVgbxOcVmmXifXaHK4nos22z5vuXeOvhHVZ+g4yRDFlG4t4d5sVcp6BrJk4W3iWR0wuMzVIRj5OiKQ9S2c8oGh7f5EKkFXkKqNswD3srIV0rYkWQWibmjizshlnxE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773333419; c=relaxed/simple; bh=PHTycdlf1dFs7CToXS9wxFQ5DOSHhKZ3v+bxy6sc4qA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kYOwfJiRpOXzACnkyz3xUhyygxQBQmr7Ytb46YeJfalL7YwLZSjRdTTRByu7rn3Xwo4oVY3CZ66vpoofTek94u9T0G7rplEEjazg7CXwlWtV2xnRIchvp3mkyE2xkp9ZCDbz/322Z6BtyijrES5R+3eIDJmLVkwW96Frne1g0eU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com 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 D9E60165C; Thu, 12 Mar 2026 09:36:49 -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 0541C3F694; Thu, 12 Mar 2026 09:36:52 -0700 (PDT) Date: Thu, 12 Mar 2026 16:36:43 +0000 From: Cristian Marussi To: Sudeep Holla Cc: Cristian Marussi , Geert Uytterhoeven , 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, 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> <20260312-classy-misty-platypus-5baea1@sudeepholla> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260312-classy-misty-platypus-5baea1@sudeepholla> On Thu, Mar 12, 2026 at 03:33:52PM +0000, Sudeep Holla wrote: > On Wed, Mar 11, 2026 at 06:45:41PM +0000, Cristian Marussi wrote: > > 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... > > > > I prefer to fix it as a quirk to prevent similar issues on newer platforms if > the firmware baselines are derived from it. In the worst case, we can relax > the hardening until we figure out a proper quirk-based solution. Ok, I can post a V3 with a dummy quirk 'template' RFC to be filled by Geert with proper versioning....so I can check that there are no surprises round the (quirked) corner... Thanks, Cristian