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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 85C39C433F5 for ; Thu, 28 Apr 2022 13:52:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347783AbiD1Nz7 (ORCPT ); Thu, 28 Apr 2022 09:55:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34152 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347725AbiD1Nz4 (ORCPT ); Thu, 28 Apr 2022 09:55:56 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id C8CF2B42D9 for ; Thu, 28 Apr 2022 06:52:40 -0700 (PDT) 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 8AAAD1474; Thu, 28 Apr 2022 06:52:40 -0700 (PDT) Received: from bogus (unknown [10.57.11.83]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 637AF3F5A1; Thu, 28 Apr 2022 06:52:38 -0700 (PDT) Date: Thu, 28 Apr 2022 14:52:33 +0100 From: Sudeep Holla To: Cristian Marussi Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, james.quinlan@broadcom.com, Jonathan.Cameron@huawei.com, f.fainelli@gmail.com, etienne.carriere@linaro.org, Sudeep Holla , vincent.guittot@linaro.org, souvik.chakravarty@arm.com Subject: Re: [PATCH 22/22] firmware: arm_scmi: Add SCMIv3.1 PERFORMANCE_LIMITS_SET checks Message-ID: <20220428135233.r2yzwgr5uxex7vox@bogus> References: <20220330150551.2573938-1-cristian.marussi@arm.com> <20220330150551.2573938-23-cristian.marussi@arm.com> <20220428131357.mbj5pksrnt5auotb@bogus> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 28, 2022 at 02:49:48PM +0100, Cristian Marussi wrote: > On Thu, Apr 28, 2022 at 02:13:57PM +0100, Sudeep Holla wrote: > > On Wed, Mar 30, 2022 at 04:05:51PM +0100, Cristian Marussi wrote: > > > Starting with SCMIv3.1, the PERFORMANCE_LIMITS_SET command allows a user > > > to request only one between max and min ranges to be changed, while leaving > > > the other untouched if set to zero in the request; anyway SCMIv3.1 states > > > also explicitly that you cannot leave both of those unchanged (zeroed) when > > > issuing such command: add a proper check for this condition. > > > > > > Signed-off-by: Cristian Marussi > > > --- > > > drivers/firmware/arm_scmi/perf.c | 3 +++ > > > 1 file changed, 3 insertions(+) > > > > > > diff --git a/drivers/firmware/arm_scmi/perf.c b/drivers/firmware/arm_scmi/perf.c > > > index 65ffda5495d6..8f4051aca220 100644 > > > --- a/drivers/firmware/arm_scmi/perf.c > > > +++ b/drivers/firmware/arm_scmi/perf.c > > > @@ -423,6 +423,9 @@ static int scmi_perf_limits_set(const struct scmi_protocol_handle *ph, > > > struct scmi_perf_info *pi = ph->get_priv(ph); > > > struct perf_dom_info *dom = pi->dom_info + domain; > > > > > > + if (PROTOCOL_REV_MAJOR(pi->version) >= 0x3 && !max_perf && !min_perf) > > > + return -EINVAL; > > > + > > > > Do we really need the version check here ? I agree it was explicitly added > > in v3.1, but it makes sense on any version really. No ? > > Indeed seemed a silly patch also to me but given that only in v3.1 it is > explicitly stated that you cannot issue this command with both min and > max ZEROED I though this could have broken older fw that allowed > setting PERF_LIMITS_SET max=0 min=0 > > ....maybe overthought ... Hmm, let's keep it unconditional for now. We can add if someone reports broken firmware. BTW there are no users in the kernel 😄. -- Regards, Sudeep