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 DCD6AC433E0 for ; Thu, 9 Jul 2020 09:23:57 +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 A87ED206A1 for ; Thu, 9 Jul 2020 09:23:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="UR+Njoc2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A87ED206A1 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.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-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=ve3gPi4uUHOUvgNOkNz1GW6MXHnmSbHm8DmwwNaGV1Y=; b=UR+Njoc2V24hApppkUxT8Ddbl Eq78+SNAioTzCI47/lF4XgJErssYJ6NUV+p7wn4uB/x9QcHyQ45uQF6qzUQTqlYQbNRz2UpNmCOSI RoNL6Af1p8E5ANc3Ja86XoABQQa7JVwuaiVPXmrVu7CNB/mou0VL/E4gfIL6Uj31YI23Cm1t6t7ZF FKEj9IBCXLob8ps15BP/2D16bjOf3fZ1EeD4Y0fV/j373rGUWmrRAwiI+dFUOL6xN5gMFIIiOxNQ9 1icHBx56VSBGHnc+SsWBDU8fyRBknGqvCwzdu/VY6oZ54K91VK7tuJ4pA3sd5EZp9xGUTr9P/LUKR O7deaLtrw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jtSkq-0005cG-Og; Thu, 09 Jul 2020 09:22:08 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jtSkn-0005bT-RU for linux-arm-kernel@lists.infradead.org; Thu, 09 Jul 2020 09:22:06 +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 143C231B; Thu, 9 Jul 2020 02:22:01 -0700 (PDT) Received: from e121166-lin.cambridge.arm.com (e121166-lin.cambridge.arm.com [10.1.196.255]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 83EC53F887; Thu, 9 Jul 2020 02:21:58 -0700 (PDT) Date: Thu, 9 Jul 2020 10:21:56 +0100 From: Lorenzo Pieralisi To: Hanjun Guo Subject: Re: [PATCH v2 01/12] ACPI/IORT: Make iort_match_node_callback walk the ACPI namespace for NC Message-ID: <20200709092156.GB18149@e121166-lin.cambridge.arm.com> 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> <4817d766-0437-5356-a0b9-97b111d4cae2@huawei.com> <952a6720-f401-1441-5548-5b40cfc76d3a@arm.com> <0cbd1da8-e283-7e13-d2b3-4d14775fd870@huawei.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <0cbd1da8-e283-7e13-d2b3-4d14775fd870@huawei.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200709_052206_037249_8F7C4D8C X-CRM114-Status: GOOD ( 42.52 ) 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, Sudeep Holla , Marc Zyngier , Will Deacon , linux-pci@vger.kernel.org, Joerg Roedel , Diana Craciun , "Rafael J. Wysocki" , iommu@lists.linux-foundation.org, linux-acpi@vger.kernel.org, Makarand Pawagi , Rob Herring , Catalin Marinas , Bjorn Helgaas , Robin Murphy , linux-arm-kernel@lists.infradead.org, Laurentiu Tudor Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Jul 02, 2020 at 04:22:00PM +0800, Hanjun Guo wrote: > Hi Robin, > > On 2020/7/2 0:12, Robin Murphy wrote: > > On 2020-06-30 14:04, Hanjun Guo wrote: > > > 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. > > > > Is that even a valid case though? The principal thing we want to > > accommodate here is when device B *is* the one accessing memory, either > > because it is a bridge with device A sat behind it, or because device A > > is actually just some logical function or subset of physical device B. > > Thanks for the clarify, for CCA attributes, child device should be the > same as its parent and that was written in the ACPI spec, so it's better > to make it clear for other properties in the spec as well. > > > > > If the topology is such that device A is a completely independent device > > with its own path to memory such that it could have different > > properties, I would expect that it *should* be described in DSDT, and I > > can't easily think of a good reason why it wouldn't be. I'm also > > struggling to imagine how it might even have an ID that had to be > > interpreted in the context of device B if it wasn't one of the cases > > above :/ > > > > I don't doubt that people could - or maybe even have - come up with crap > > DSDT bindings that don't represent the hardware sufficiently accurately, > > but I'm not sure that should be IORT's problem... > > As I said in previous email, I'm not against this patch, and seems > have no regressions for platforms that using named component node > such as D05/D06 (I will test it shortly to make sure), but it's better > to update the wording of the spec (even after this patch set is merged). Have you managed to test this series ? Thanks, Lorenzo _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel