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 1D898C2BB1D for ; Sat, 18 Apr 2020 02:16:48 +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 D445A221E9 for ; Sat, 18 Apr 2020 02:16:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="HgcgWuMK" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D445A221E9 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:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=ZGZw5dFfLinfkgNg0guLG/5Wr7RJVPeSl1A3TBCzq6g=; b=HgcgWuMKeYs0O5woYVoZ9D4mM a4O6j6EWr9GJfEbMZ8UGKWHIDR1aroRvph9bIk8ZDbaNLp00YaEHszQCrcco+aOrhORTwgT/epc9p 6/Vl5y5QX0II9cqhbYre1FyPYzPNP+KwAJ+znEIshajKPy+agur73lj/55+yRmyjZkI7e+AfGZGAJ rmqRDDFNi0sTE72f/gAfLtng1k6se48l/rWIHXfPo3ANXQF05eaMg0fKmYIF7JCrdFyr5CbUusik7 TgUjrh1FL5LgLd3CckRgRuZTVWhBVnFHPbKTbY6x/L8/hQGA9PzxNFrjyBJNtD4JL0kRh918gUNcC M17TxfXKA==; 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 1jPd2E-0000gc-MA; Sat, 18 Apr 2020 02:16:46 +0000 Received: from szxga05-in.huawei.com ([45.249.212.191] helo=huawei.com) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jPd29-0000bj-1q for linux-arm-kernel@lists.infradead.org; Sat, 18 Apr 2020 02:16:42 +0000 Received: from DGGEMS404-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 02A29E93685C5E254919; Sat, 18 Apr 2020 10:16:25 +0800 (CST) Received: from [127.0.0.1] (10.166.213.93) by DGGEMS404-HUB.china.huawei.com (10.3.19.204) with Microsoft SMTP Server id 14.3.487.0; Sat, 18 Apr 2020 10:16:15 +0800 Subject: Re: ACPI support for System Control and Management Interface (SCMI) To: Souvik Chakravarty , Sudeep Holla References: <52a50069-7140-b9b4-31b4-8c99e8c0d991@huawei.com> <20200414105424.GB17835@bogus> From: Hanjun Guo Message-ID: Date: Sat, 18 Apr 2020 10:16:14 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-GB X-Originating-IP: [10.166.213.93] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200417_191641_264428_0E33BAB8 X-CRM114-Status: GOOD ( 11.97 ) 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: Thanu Rangarajan , John Garry , Linuxarm , Shameerali Kolothum Thodi , Matteo Carlini , Jonathan Cameron , "linux-arm-kernel@lists.infradead.org" , Charles Garcia-Tobin 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 Hi Sudeep, Souvik, On 2020/4/14 20:08, Souvik Chakravarty wrote: >> From: Sudeep Holla >> Subject: Re: ACPI support for System Control and Management Interface >> (SCMI) >> >> On Fri, Apr 10, 2020 at 10:26:41AM +0800, Hanjun Guo wrote: >>> Hi Sudeep, >>> >>> We are working on the enablement of SCMI for Kunepeng920, which is a >>> server chip using ACPI, but I didn't see the ACPI support in the >>> mainline kernel for SCMI. >>> >>> Kunpeng920 and the upcomming Kunpeng930 have thermal sensors and >> other >>> system management features which needs the SCMI for abstraction layer, >>> do we have plan to support ACPI for SCMI? >>> >> >> Yes and No. >> >> Yes, because the same SCMI compliant firmware needs to work with ACPI as >> SCMI is designed so. >> >> No, because we don't plan to add another SCMI layer below ACPI in the >> kernel. ACPI specification was extended to support special PCC types to >> support the same. IIUC things like sensors are supported using power meter >> objects in ACPI and you must be able to use PCC opregion for it or any >> custom mechanism to achieve that. However one need to add PCC opregion >> handler in Linux. The main idea is you must use existing ACPI methods and >> we don't plan to add anything special for SCMI. > > Additionally, if you already have an SCMI compliant firmware that uses > Shared Memory based transport, it is compatible with PCC Type 3 Channels > in ACPI. We had a disscusion interally (with firmware folks) and this works for our sensor usecase too, thanks! > >> >> SCMI Perf protocol is compatible with CPPC. We can discuss details once you >> explore PCC opregion or any alternative you come up with. I am no ACPI >> firmware expert and I reckon you may have other interesting ideas. Sensor works via PCC channels, and SCMI based clock/reset/cpufreq also have other abstraction level to make it work on ACPI based system, so for now no more requirements are needed, I will update if we got new ones :) Thanks Hanjun _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel