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 8263810F2847 for ; Fri, 27 Mar 2026 15:47:21 +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:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=uLwZxg+OX1A3lxVf5y7n4bPyXEh1Tpg8FCtox+FDlqs=; b=tQPlyQtjjHpaxAGa7o+nHCCgxl gH4sxCmsQqpK6wUtx+soTEOpjtFClPwrGSzEXhelSqSp8VT0baN3pbvhtpDl/QYI9lRN55mlwyO86 R7zXAppSljtn9hcd6MrxHsnwT9wAV99MyuqlW/pVeTROx7BRi29pr06PzmqaEV1qgL53tndFtWDOy 7OAL9DRfig19TU4668vsv+B0pPOJkcD2x/qWtg4ofuuvPfW1B9IXtxA6FFLti8JOVMDQMI/oSVT11 nG3vS4y1bFRL/vsKfIkp+XGOZGB9I/p41lszKZrWf3NL4eaWPY87yypW695hMpDAZtvX7eSS2bZ1Q jS5ZjC/w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w69P2-00000007iWI-1Awq; Fri, 27 Mar 2026 15:47:16 +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 1w69Oz-00000007iVo-3WB1 for linux-arm-kernel@lists.infradead.org; Fri, 27 Mar 2026 15:47:14 +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 C6C9D35E4; Fri, 27 Mar 2026 08:47:06 -0700 (PDT) Received: from [10.1.196.96] (eglon.cambridge.arm.com [10.1.196.96]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id AD5713FBF8; Fri, 27 Mar 2026 08:47:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1774626432; bh=FwlH74TR5RapPRWbQ8EZJzyzw7m7rDT/kv8QOqeRWLk=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Pn20w3r64JfebMfmtSSXpMWLvZj0MW+93FnR/sIQAHXY3Yh+woGkOkAEN7/vouEe8 rMQt2APDwyIa+dvsmtRvzT2LBNxcN/Hp+0fUyqh8m4c5rC16B34QqkzETJw1qYEnxz ns9SzT3OlvGzT4iOmXuuQP6ir2beZrTs4/b/DXvQ= Message-ID: <85c10fab-9b4e-4a57-9b4e-42adcd069a5e@arm.com> Date: Fri, 27 Mar 2026 15:47:02 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 22/40] arm_mpam: resctrl: Convert to/from MPAMs fixed-point formats To: Gavin Shan , Ben Horgan Cc: amitsinght@marvell.com, baisheng.gao@unisoc.com, baolin.wang@linux.alibaba.com, carl@os.amperecomputing.com, dave.martin@arm.com, david@kernel.org, dfustini@baylibre.com, fenghuay@nvidia.com, jonathan.cameron@huawei.com, kobak@nvidia.com, lcherian@marvell.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, peternewman@google.com, punit.agrawal@oss.qualcomm.com, quic_jiles@quicinc.com, reinette.chatre@intel.com, rohit.mathew@arm.com, scott@os.amperecomputing.com, sdonthineni@nvidia.com, tan.shaopeng@fujitsu.com, xhao@linux.alibaba.com, catalin.marinas@arm.com, will@kernel.org, corbet@lwn.net, maz@kernel.org, oupton@kernel.org, joey.gouly@arm.com, suzuki.poulose@arm.com, kvmarm@lists.linux.dev, zengheng4@huawei.com, linux-doc@vger.kernel.org, Shaopeng Tan References: <20260313144617.3420416-1-ben.horgan@arm.com> <20260313144617.3420416-23-ben.horgan@arm.com> Content-Language: en-GB From: James Morse In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260327_084713_912092_4C2A4887 X-CRM114-Status: GOOD ( 13.45 ) 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 Hi Gavin, On 23/03/2026 22:49, Gavin Shan wrote: > On 3/14/26 12:45 AM, Ben Horgan wrote: >> From: Dave Martin >> >> MPAM uses a fixed-point formats for some hardware controls.  Resctrl >> provides the bandwidth controls as a percentage. Add helpers to convert >> between these. >> >> Ensure bwa_wd is at most 16 to make it clear higher values have no meaning. > One nitpick below, but this looks good to me in either way. > > Reviewed-by: Gavin Shan Thanks! >> diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c >> index 0e5e24ef60fe..0c97f7708722 100644 >> --- a/drivers/resctrl/mpam_devices.c >> +++ b/drivers/resctrl/mpam_devices.c >> @@ -713,6 +713,13 @@ static void mpam_ris_hw_probe(struct mpam_msc_ris *ris) >>               mpam_set_feature(mpam_feat_mbw_part, props); >>             props->bwa_wd = FIELD_GET(MPAMF_MBW_IDR_BWA_WD, mbw_features); >> + >> +        /* >> +         * The BWA_WD field can represent 0-63, but the control fields it >> +         * describes have a maximum of 16 bits. >> +         */ >> +        props->bwa_wd = min(props->bwa_wd, 16); >> + > > 16 may deserve a definition for it since it's a constant value and referred > for multiple times in this patch, if we need to give this series another > respin :-) Hmmm.,. I've left this, I'm not sure what you'd call it. U16_BITS? That sort of thing might be needed for long/int etc. Here there is either a comment, or its accepting/returning a u16. I think its fairly obvious where the number 16 is coming from. Thanks, James