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 X-Spam-Level: X-Spam-Status: No, score=-5.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9D731C43381 for ; Wed, 20 Mar 2019 08:19:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6E47B21871 for ; Wed, 20 Mar 2019 08:19:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553069960; bh=nkM+KtRVPjQUt1pQmj9DalXM/7+xvh8bqtVNzoBCheQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=j5UizZApbw/UsZ2hm2vQdz5tEq99bUO0BIOMvuuq51xgC8WgnQDs+tf6ZeVYD6WG5 7UL4OsSeqK+kLqdE+8Ubu7dKqhRnM18B32RHeWB3qQh7r9wjlbx3bxsk4m5Ijyfgcg K0A76uh+TN4YzzERoG8jSqBDvsRnm4pxLHVfn3SM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727837AbfCTITT (ORCPT ); Wed, 20 Mar 2019 04:19:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:58250 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725996AbfCTITS (ORCPT ); Wed, 20 Mar 2019 04:19:18 -0400 Received: from dragon (98.142.130.235.16clouds.com [98.142.130.235]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 79C0C20657; Wed, 20 Mar 2019 08:19:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553069956; bh=nkM+KtRVPjQUt1pQmj9DalXM/7+xvh8bqtVNzoBCheQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=RGvogefzjixxnh/ZE1SX1tpWVM5SQdUinz9ZNVaSv/nueFt6jUWAxQRazzLhvrdkD sMkhl9hZScXnD0vj62XWuzVxxIwA9WfvDYX5G9NteR0DbiAObTqJPUQanU1LRcF/E+ 9J9BOeI9InyBCACqgfih9J2hqEugTLlYsy+UqBxQ= Date: Wed, 20 Mar 2019 16:18:55 +0800 From: Shawn Guo To: Andy Tang Cc: Daniel Lezcano , "mark.rutland@arm.com" , "devicetree@vger.kernel.org" , "linux-pm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Leo Li , "edubezval@gmail.com" , "robh+dt@kernel.org" , "rui.zhang@intel.com" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH v2] arm64: dts: ls1088a: add one more thermal zone node Message-ID: <20190320081853.GE4980@dragon> References: <20190304032111.21770-1-andy.tang@nxp.com> <20190304062115.GB26041@dragon> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 08, 2019 at 09:57:09AM +0000, Andy Tang wrote: > > > > -----Original Message----- > > From: Daniel Lezcano > > Sent: 2019年3月8日 17:28 > > To: Andy Tang ; Shawn Guo > > Cc: Leo Li ; robh+dt@kernel.org; mark.rutland@arm.com; > > linux-arm-kernel@lists.infradead.org; devicetree@vger.kernel.org; > > linux-kernel@vger.kernel.org; linux-pm@vger.kernel.org; rui.zhang@intel.com; > > edubezval@gmail.com > > Subject: Re: [PATCH v2] arm64: dts: ls1088a: add one more thermal zone node > > > > On 08/03/2019 03:07, Andy Tang wrote: > > > > > > > > >> -----Original Message----- > > >> From: Daniel Lezcano > > >> Sent: 2019年3月7日 17:15 > > >> To: Andy Tang ; Shawn Guo > > >> Cc: Leo Li ; robh+dt@kernel.org; > > >> mark.rutland@arm.com; linux-arm-kernel@lists.infradead.org; > > >> devicetree@vger.kernel.org; linux-kernel@vger.kernel.org; > > >> linux-pm@vger.kernel.org; rui.zhang@intel.com; edubezval@gmail.com > > >> Subject: Re: [PATCH v2] arm64: dts: ls1088a: add one more thermal > > >> zone node > > >> > > >>>>> PS: In order to keep consistency to the first thermal-zone node, > > >>>>> there will be "WARNING: line over 80 characters" warnings. > > >>>>> > > >>>>> arch/arm64/boot/dts/freescale/fsl-ls1088a.dtsi | 43 > > >>>> +++++++++++++++++++++-- > > >>>>> 1 files changed, 39 insertions(+), 4 deletions(-) > > >>>>> > > >>>>> diff --git a/arch/arm64/boot/dts/freescale/fsl-ls1088a.dtsi > > >>>>> b/arch/arm64/boot/dts/freescale/fsl-ls1088a.dtsi > > >>>>> index 661137f..9f52bc9 100644 > > >>>>> --- a/arch/arm64/boot/dts/freescale/fsl-ls1088a.dtsi > > >>>>> +++ b/arch/arm64/boot/dts/freescale/fsl-ls1088a.dtsi > > >>>>> @@ -129,19 +129,19 @@ > > >>>>> }; > > >>>>> > > >>>>> thermal-zones { > > >>>>> - cpu_thermal: cpu-thermal { > > >>>>> + ccu { > > >>>> > > >>>> Is this change really necessary? What does 'ccu' stand for? > > >>> I think so. ccu stands for core cluster unit. cpu is too general. > > >>> On some platforms, there are more than one core clusters. > > >>> At least we should change it to "core cluster" if short form is not > > appropriate. > > >> > > >> If the sensor is a the cluster level, 'cluster' is enough. IMHO, no > > >> need to give a description of what contains the cluster, otherwise > > >> you will end up with a 'core-gpu-cluster-l2' name. > > > If cluster is specific to core, we can use cluster instead. But I don't think so. > > > Cluster may refer to "core cluster", "GPU cluster" etc. > > > So, I think "core-cluster" is ok. > > > If core was divided to several clusters, we can name it as "core-cluster1", > > "core-cluster2" etc. > > > If GPU was divided to several clusters we can name it as "gpu-cluster1", > > "gpu-cluster2" etc. > > > > > > Hi Andy, > > > > I think there is a confusion around the 'cpu' term and 'cluster'. > > > > ARM would like to see the 'cluster' word to disappear, so whenever possible we > > should avoid it. > > > > From the hardware side, 'CPU' is usually used to describe the physical chip > > containing the cores+cache. > > > > From the software side, 'CPU' is usually used to describe the logical process > > unit, aka a core or a hyper-thread. > > > > As we are in the DT, so describing the hardware, the CPU refers to the group > > cores+caches. > > > > From my POV, using 'cpu' for the group of cores and 'gpu' for the graphic > > sounds ok, and so far that is what is used for the other platforms. > > > > If you change the name, that may give the feeling there is something special > > with those thermal zones. > > Thanks Daniel for your detailed explanations. > > But as you said 'CPU' is usually used to describe the physical chip. Here is how I would understand Daniel's comments: CPU = cores + caches physical chip = SoC = CPU + GPU + peripherals ... > So if we name it as CPU, it sounds like this temperature sensor is monitoring the whole chip. > That's not true in our case. > > Take ls2088a for example: > In ls2088a SoC, there are 7 temperature sensors. Please note that they are all located in SoC. > The placement of the temperature sensors are showed below: > > Sensor ID placement > 1 DDR controller 1 > 2 DDR controller 2 > 3 DDR controller 3 > 4 core cluster 1 > 5 core cluster 2 > 6 core cluster 3 > 7 core cluster 4 > > Apparently using CPU or CPU-cluster is not appropriate. Core-cluster is better. So using CPU is appropriate for me, less confusing, more consistent with other platforms. Shawn