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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 2E169C433DF for ; Wed, 27 May 2020 14:35:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0F68320899 for ; Wed, 27 May 2020 14:35:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389310AbgE0Of4 (ORCPT ); Wed, 27 May 2020 10:35:56 -0400 Received: from lhrrgout.huawei.com ([185.176.76.210]:2249 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2389205AbgE0Of4 (ORCPT ); Wed, 27 May 2020 10:35:56 -0400 Received: from lhreml724-chm.china.huawei.com (unknown [172.18.7.108]) by Forcepoint Email with ESMTP id B48B11895055C8A31AB1; Wed, 27 May 2020 15:35:53 +0100 (IST) Received: from [127.0.0.1] (10.47.6.244) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1913.5; Wed, 27 May 2020 15:35:52 +0100 From: John Garry Subject: Re: [PATCH V1 RESEND 1/3] perf/imx_ddr: Add system PMU identifier for userspace To: Will Deacon , Rob Herring CC: Mark Rutland , , Joakim Zhang , "linux-kernel@vger.kernel.org" , NXP Linux Team , Shawn Guo , "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" , Zhangshaokun References: <20200512073115.14177-1-qiangqing.zhang@nxp.com> <20200512073115.14177-2-qiangqing.zhang@nxp.com> <20200519185125.GB453195@bogus> <20200520073304.GA23534@willie-the-truck> <20200521130415.GB5949@willie-the-truck> Message-ID: <51aa7cbc-0ce2-b96d-b056-fcc6013ccecf@huawei.com> Date: Wed, 27 May 2020 15:34:48 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.47.6.244] X-ClientProxiedBy: lhreml717-chm.china.huawei.com (10.201.108.68) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>>> >>>> I also really dislike this. What's the preferred way to identify the >>>> SoC >>>> from userspace? >>> >>> /proc/cpuinfo? ;) >> >> The *SoC*! >> >>> For an non-firmware specific case, I'd say soc_device should be. I'd >>> guess ACPI systems don't use it and for them it's dmidecode typically. >>> The other problem I have with soc_device is it is optional. >> > > Hi Will, > >> John -- what do you think about using soc_device to expose this >> information, >> with ACPI systems using DMI data instead? > > Generally I don't think that DMI is reliable, and I saw this as the > least preferred choice. I'm looking at the sysfs DMI info for my dev > board, and I don't even see anything like a SoC identifier. > > As for the event_source device sysfs identifier file, it would not > always contain effectively the same as the SoC ID. > > Certain PMUs which I'm interested in plan to have probe-able > identification info available in future. > BTW, Shaokun now tells me that the HiSi uncore PMU HW have such registers to identify the implementation. I didn't know. So we could add that identifier file for those PMUs as proof-of-concept, exposing that register. As for other PMUs which I'm interested in, again, future versions should have such registers to self-identify. So using something derived from the DT compat string would hopefully be the uncommon case. Cheers, John 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=-2.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 9DE15C433DF for ; Wed, 27 May 2020 14:36:23 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 652D2207D8 for ; Wed, 27 May 2020 14:36:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="VHLydcgM" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 652D2207D8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:References: To:Subject:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=EUYwnVti7CLVsLFGuN0HYm6WyxmhW9Bsredj8sZ8LpY=; b=VHLydcgMurf0OWbhFjRPZtdlx VEKmMe7w1B/VTQQpYlSxK80u6rK5GjHQSxemqwW2MqU0So/LTJyIHSpI2Xy7nUe+bmDWnnavT4k+H x2cSADpAdgqhflfiLSv/t+P4Uo+Zz+lXRarW4Kb+tw6HlxxFq1phnNDgcjiYLFDusv8UkObb5QbNr byx/9RaC4WqUkdvxVw89yla6gnJzilEFpKCHrTQGNkoR3Xv3eGYq6J0aCS1V+0xC34PW9N6wkWpIh DGgtl+rX3tSPcebQxejKnLAFkVuKA15C+4FEDhLXEJES4yzcR26r3IuEjHyEmH6bikLqhnSavPNm+ GPMhEONcg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jdxAM-00076Q-Bb; Wed, 27 May 2020 14:36:22 +0000 Received: from lhrrgout.huawei.com ([185.176.76.210] helo=huawei.com) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jdxAI-00074r-VP for linux-arm-kernel@lists.infradead.org; Wed, 27 May 2020 14:36:20 +0000 Received: from lhreml724-chm.china.huawei.com (unknown [172.18.7.108]) by Forcepoint Email with ESMTP id B48B11895055C8A31AB1; Wed, 27 May 2020 15:35:53 +0100 (IST) Received: from [127.0.0.1] (10.47.6.244) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1913.5; Wed, 27 May 2020 15:35:52 +0100 From: John Garry Subject: Re: [PATCH V1 RESEND 1/3] perf/imx_ddr: Add system PMU identifier for userspace To: Will Deacon , Rob Herring References: <20200512073115.14177-1-qiangqing.zhang@nxp.com> <20200512073115.14177-2-qiangqing.zhang@nxp.com> <20200519185125.GB453195@bogus> <20200520073304.GA23534@willie-the-truck> <20200521130415.GB5949@willie-the-truck> Message-ID: <51aa7cbc-0ce2-b96d-b056-fcc6013ccecf@huawei.com> Date: Wed, 27 May 2020 15:34:48 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-Originating-IP: [10.47.6.244] X-ClientProxiedBy: lhreml717-chm.china.huawei.com (10.201.108.68) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200527_073619_152639_51EC390A X-CRM114-Status: GOOD ( 16.82 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , devicetree@vger.kernel.org, Joakim Zhang , "linux-kernel@vger.kernel.org" , Zhangshaokun , NXP Linux Team , Shawn Guo , "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org >>>> >>>> I also really dislike this. What's the preferred way to identify the >>>> SoC >>>> from userspace? >>> >>> /proc/cpuinfo? ;) >> >> The *SoC*! >> >>> For an non-firmware specific case, I'd say soc_device should be. I'd >>> guess ACPI systems don't use it and for them it's dmidecode typically. >>> The other problem I have with soc_device is it is optional. >> > > Hi Will, > >> John -- what do you think about using soc_device to expose this >> information, >> with ACPI systems using DMI data instead? > > Generally I don't think that DMI is reliable, and I saw this as the > least preferred choice. I'm looking at the sysfs DMI info for my dev > board, and I don't even see anything like a SoC identifier. > > As for the event_source device sysfs identifier file, it would not > always contain effectively the same as the SoC ID. > > Certain PMUs which I'm interested in plan to have probe-able > identification info available in future. > BTW, Shaokun now tells me that the HiSi uncore PMU HW have such registers to identify the implementation. I didn't know. So we could add that identifier file for those PMUs as proof-of-concept, exposing that register. As for other PMUs which I'm interested in, again, future versions should have such registers to self-identify. So using something derived from the DT compat string would hopefully be the uncommon case. Cheers, John _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel