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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 1649FC433E0 for ; Mon, 29 Jun 2020 18:35:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0333A255D8 for ; Mon, 29 Jun 2020 18:35:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726010AbgF2Se5 (ORCPT ); Mon, 29 Jun 2020 14:34:57 -0400 Received: from foss.arm.com ([217.140.110.172]:34560 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725887AbgF2Se5 (ORCPT ); Mon, 29 Jun 2020 14:34:57 -0400 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 73384113E; Mon, 29 Jun 2020 02:06:00 -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 0412D3F71E; Mon, 29 Jun 2020 02:05:57 -0700 (PDT) Date: Mon, 29 Jun 2020 10:05:51 +0100 From: Lorenzo Pieralisi To: Hanjun Guo Cc: linux-arm-kernel@lists.infradead.org, Will Deacon , Sudeep Holla , Catalin Marinas , Robin Murphy , "Rafael J. Wysocki" , iommu@lists.linux-foundation.org, linux-acpi@vger.kernel.org, devicetree@vger.kernel.org, linux-pci@vger.kernel.org, Rob Herring , Joerg Roedel , Bjorn Helgaas , Marc Zyngier , Makarand Pawagi , Diana Craciun , Laurentiu Tudor Subject: Re: [PATCH v2 01/12] ACPI/IORT: Make iort_match_node_callback walk the ACPI namespace for NC Message-ID: <20200629090551.GA28873@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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <718cae1f-2f33-f6d9-f278-157300b73116@huawei.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Mon, Jun 29, 2020 at 12:24:43PM +0800, Hanjun Guo wrote: > Hi Lorenzo, > > On 2020/6/19 16:20, Lorenzo Pieralisi wrote: > > When the iort_match_node_callback is invoked for a named component > > the match should be executed upon a device with an ACPI companion. > > > > For devices with no ACPI companion set-up the ACPI device tree must be > > walked in order to find the first parent node with a companion set and > > check the parent node against the named component entry to check whether > > there is a match and therefore an IORT node describing the in/out ID > > translation for the device has been found. > > > > Signed-off-by: Lorenzo Pieralisi > > Cc: Will Deacon > > Cc: Hanjun Guo > > Cc: Sudeep Holla > > Cc: Catalin Marinas > > Cc: Robin Murphy > > Cc: "Rafael J. Wysocki" > > --- > > drivers/acpi/arm64/iort.c | 20 ++++++++++++++++++-- > > 1 file changed, 18 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c > > index 28a6b387e80e..5eee81758184 100644 > > --- a/drivers/acpi/arm64/iort.c > > +++ b/drivers/acpi/arm64/iort.c > > @@ -264,15 +264,31 @@ static acpi_status iort_match_node_callback(struct acpi_iort_node *node, > > if (node->type == ACPI_IORT_NODE_NAMED_COMPONENT) { > > struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL }; > > - struct acpi_device *adev = to_acpi_device_node(dev->fwnode); > > + struct acpi_device *adev; > > struct acpi_iort_named_component *ncomp; > > + struct device *nc_dev = dev; > > + > > + /* > > + * Walk the device tree to find a device with an > > + * ACPI companion; there is no point in scanning > > + * IORT for a device matching a named component if > > + * the device does not have an ACPI companion to > > + * start with. > > + */ > > + do { > > + adev = ACPI_COMPANION(nc_dev); > > + if (adev) > > + break; > > + > > + nc_dev = nc_dev->parent; > > + } while (nc_dev); > > I'm lost here, we need the ACPI_COMPANION (the same as > to_acpi_device_node()) of the device, but why do we need to go > up to find the parent node? 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 ? > 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. Thanks, Lorenzo