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=-2.5 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 32FE2C433E0 for ; Tue, 30 Jun 2020 13:06:03 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 0219820672 for ; Tue, 30 Jun 2020 13:06:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="f4K+sRGW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0219820672 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+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=merlin.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=tb6cNoYawXGDMIci8GnU1MWtNL7fBHNFMMqUokNBCaQ=; b=f4K+sRGW6hPvu5/ekR1LKM2q+ OaoUSv0rhf9UTEGBpdtpolasp68j8WENE360DBOBRewTPr1zXThQWSsA1IW8AAu0YiidCK6b4Qmlj FTMJPHiwu4quvCFLVFl8m/7pNofTSXQw4O3scr7S1zTxWwkxNRezlr5KLHO1t0f85J6uq0hbab6eB dNAliTWlYd+rhrSvuEh8ewyxeINK/SXNcllir5EOFRtrcGflsthOdBVwUG3uBml4kvTcGcZcfRNbf qj2bey6/NRqaBNxKMVVPR+otMuuqTaaXAm2lPu/gw3qUJuM8MdMQtIx2VXCsEY4bc+6EbbV6Dry5O S1K5aM71g==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jqFwH-00018l-QM; Tue, 30 Jun 2020 13:04:41 +0000 Received: from szxga05-in.huawei.com ([45.249.212.191] helo=huawei.com) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jqFwE-00015q-KL for linux-arm-kernel@lists.infradead.org; Tue, 30 Jun 2020 13:04:40 +0000 Received: from DGGEMS402-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 27BDADEC1BEF76A390DF; Tue, 30 Jun 2020 21:04:24 +0800 (CST) Received: from [127.0.0.1] (10.174.179.33) by DGGEMS402-HUB.china.huawei.com (10.3.19.202) with Microsoft SMTP Server id 14.3.487.0; Tue, 30 Jun 2020 21:04:21 +0800 Subject: Re: [PATCH v2 01/12] ACPI/IORT: Make iort_match_node_callback walk the ACPI namespace for NC To: Lorenzo Pieralisi References: <20200521130008.8266-1-lorenzo.pieralisi@arm.com> <20200619082013.13661-1-lorenzo.pieralisi@arm.com> <20200619082013.13661-2-lorenzo.pieralisi@arm.com> <718cae1f-2f33-f6d9-f278-157300b73116@huawei.com> <20200629090551.GA28873@e121166-lin.cambridge.arm.com> <765078e7-b3ec-af5d-0405-7834ba0f120a@huawei.com> <20200630102454.GA17556@e121166-lin.cambridge.arm.com> From: Hanjun Guo Message-ID: <4817d766-0437-5356-a0b9-97b111d4cae2@huawei.com> Date: Tue, 30 Jun 2020 21:04:20 +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: <20200630102454.GA17556@e121166-lin.cambridge.arm.com> Content-Language: en-GB X-Originating-IP: [10.174.179.33] X-CFilter-Loop: Reflected 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: devicetree@vger.kernel.org, Marc Zyngier , Makarand Pawagi , linux-pci@vger.kernel.org, Catalin Marinas , Joerg Roedel , Diana Craciun , "Rafael J. Wysocki" , Robin Murphy , linux-acpi@vger.kernel.org, iommu@lists.linux-foundation.org, Rob Herring , Sudeep Holla , Bjorn Helgaas , Will Deacon , linux-arm-kernel@lists.infradead.org, Laurentiu Tudor Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2020/6/30 18:24, Lorenzo Pieralisi wrote: > On Tue, Jun 30, 2020 at 11:06:41AM +0800, Hanjun Guo wrote: > > [...] > >>> For devices that aren't described in the DSDT - IORT translations >>> are determined by their ACPI parent device. Do you see/Have you >>> found any issue with this approach ? >> >> The spec says "Describes the IO relationships between devices >> represented in the ACPI namespace.", and in section 3.1.1.3 Named >> component node, it says: > > PCI devices aren't necessarily described in the ACPI namespace and we > still use IORT to describe them - through the RC node. > >> "Named component nodes are used to describe devices that are also >> included in the Differentiated System Description Table (DSDT). See >> [ACPI]." >> >> So from my understanding, the IORT spec for now, can only do ID >> translations for devices in the DSDT. > > I think you can read this multiple ways but this patch does not > change this concept. What changes, is applying parent's node IORT > mapping to child nodes with no associated DSDT nodes, it is the > same thing we do with PCI and the _DMA method - we could update > the wording in the specs if that clarifies but I don't think this > deliberately disregards the specifications. I agree, but it's better to update the wording of the spec. > >>>> For a platform device, if I use its parent's full path name for >>>> its named component entry, then it will match, but this will violate >>>> the IORT spec. >>> >>> Can you elaborate on this please I don't get the point you >>> are making. >> >> For example, device A is not described in DSDT so can't represent >> as a NC node in IORT. Device B can be described in DSDT and it >> is the parent of device A, so device B can be represented in IORT >> with memory access properties and node flags with Substream width >> and Stall supported info. >> >> When we trying to translate device A's ID, we reuse all the memory >> access properties and node flags from its parent (device B), but >> will it the same? > > I assume so why wouldn't it be ? Why would be describe them in > a parent-child relationship if that's not how the system looks like > in HW ? The point I'm making is that I'm not sure all the memory access and stall properties are the same for the parent and the device itself. > > Do you have a specific example in mind that we should be aware of ? > >> So the IORT spec don't support this, at least it's pretty vague >> I think. > > I think that's a matter of wording, it can be updated if it needs be, > reach out if you see any issue with the current approach please. If the all the properties for parent and device itself are the same, I have no strong opinion for this patch, but it's better to update the wording of the spec as well. Thanks Hanjun _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel