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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 52A5FCC6B38 for ; Thu, 15 Oct 2026 19:36:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc: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=0ExLOTvMpNdwpLI0kZtOgkFwCcZ4IqWfr3EbUwrSECg=; b=0gzihVrhWVIPnO5ZIjBhfkwVHR 1r0YAIMpyrois9r1noJTJtRI9xP+TBnHA+iZ/ykmjoq8SaxQoh9wKCRsrgbFl0XTSYnBiXis1FZHJ I1SoLl8URtsWlrwvwB2TiTR/gH/D4pRw1owW7XdsNASE3AzdBgSxM4/eqe4F0b7rqhpE4FSg273cE 6bYV4z6hhu4aQ5aJkA98r8sEzr4zLJHcCnzoV56uWiJo6AA2ELgZ/s08nWFwGHadJ4BauFrwwl+9q vh5DvREWGDIW5rba9UzUqakJyw2oxpwuDnT5M6tGRmcOnQaqh6O3HW8cttg2HVWAqYOzTr2D5y9tK rqn+r4mA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xHRFr-00000001G4L-2HQx; Thu, 15 Oct 2026 19:36:43 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1xHRFp-00000001G3o-49YX for linux-arm-kernel@lists.infradead.org; Thu, 15 Oct 2026 19:36:42 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 6AD6840596; Thu, 15 Oct 2026 19:36:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0B4411F000C4; Thu, 15 Oct 2026 19:36:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792093001; bh=0ExLOTvMpNdwpLI0kZtOgkFwCcZ4IqWfr3EbUwrSECg=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=kLw0KzYYomReQQbQQ+K2sJiVxDSsJH3OUDHmvawLUtBzvBzvcoW02JSoYsrIVSOS9 o3t+C+DkAJOuGf8MwzrhLtFqBHaKpuB89H0Eqh8m3+VrAI/Qaxxgrty/FBnR9QmXbc mV+TBLIA4H6rnBhyWJRcwojbpXOxNKsODmequC9xvI5dGd5vBUad4/F0uLMJzOldK0 T8t3g8LrSrBoo9dTrKfxNetSr+mDHHmzhX6hSeT3ZK99f/QhtkTUQnp1NUyPJra700 T+eGYsGTzKY8rFD1jN0Q+jSpSCCSCYLlI+KA4Qie5tMdCcCdVE826GzWfz5sj6+yP5 /nKwaas4pTTog== Date: Thu, 15 Oct 2026 14:36:39 -0500 From: Rob Herring To: Yin Li Cc: James Morse , Shanker Donthineni , Ben Horgan , Krzysztof Kozlowski , Conor Dooley , Catalin Marinas , Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich , Reinette Chatre , Fenghua Yu , Jonathan Cameron , Bjorn Andersson , Konrad Dybcio , Gavin Shan , Andre Przywara , Drew Fustini , Ilpo =?iso-8859-1?Q?J=E4rvinen?= , Shaopeng Tan , trilok.soni@oss.qualcomm.com, aiqun.yu@oss.qualcomm.com, ganapatrao.kulkarni@oss.qualcomm.com, Srivathsa L Rao , Huang Yiwei , linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, driver-core@lists.linux.dev, devicetree@vger.kernel.org Subject: Re: [PATCH v3 3/8] dt-bindings: arm: Add MPAM MSC binding Message-ID: <20261015193639.GE5059-robh@kernel.org> References: <20261008-mpam-resctrl-dt-knp-support-v3-0-35196c2b43bf@oss.qualcomm.com> <20261008-mpam-resctrl-dt-knp-support-v3-3-35196c2b43bf@oss.qualcomm.com> <20261008212736.GB1318789-robh@kernel.org> <2eddfb6d-c622-4d72-827e-aed685e72b9c@oss.qualcomm.com> <51bc6576-7e52-4685-b7b2-a355c2b7e1ae@oss.qualcomm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <51bc6576-7e52-4685-b7b2-a355c2b7e1ae@oss.qualcomm.com> X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Oct 12, 2026 at 06:24:06PM +0800, Yin Li wrote: > > > On 10/12/2026 3:05 PM, Yin Li wrote: > > > > > > On 10/9/2026 5:27 AM, Rob Herring wrote: > > > On Thu, Oct 08, 2026 at 02:41:12PM +0800, Yin Li wrote: > > > > From: Rob Herring > > > > > > > > The binding is designed around the assumption that an MSC will be a > > > > sub-block of something else such as a memory controller, cache > > > > controller, > > > > or IOMMU. However, it's certainly possible a design does not have that > > > > association or has a mixture of both, so the binding illustrates > > > > how we can > > > > support that with RIS child nodes. > > > > > > > > A key part of MPAM is we need to know about all of the MSCs in > > > > the system > > > > before it can be enabled. This drives the need for the genericish > > > > 'arm,mpam-msc' compatible. Though we can't assume an MSC is accessible > > > > until a h/w specific driver potentially enables the h/w. > > > > > > > > Cc: James Morse > > > > Signed-off-by: Rob Herring > > > > Signed-off-by: James Morse > > > > [ Yin Li and Huang Yiwei: use oneOf for the compatible to allow both > > > >    standalone arm,mpam-msc and the two-item combination; fix > > > > schema field > > > >    order, type constraints and yamllint spacing; fix example reg > > > > addresses, > > > >    add arm,mpam-device phandle and remove TODO comment ] > > > > Co-developed-by: Huang Yiwei > > > > Signed-off-by: Huang Yiwei > > > > Signed-off-by: Yin Li > > > > --- > > > >   .../devicetree/bindings/arm/arm,mpam-msc.yaml      | 202 > > > > ++++++++++ +++++++++++ > > > >   1 file changed, 202 insertions(+) > > > > > > > > diff --git > > > > a/Documentation/devicetree/bindings/arm/arm,mpam-msc.yaml > > > > b/Documentation/devicetree/bindings/arm/arm,mpam-msc.yaml > > > > new file mode 100644 > > > > index 000000000000..3c7b13a23ff2 > > > > --- /dev/null > > > > +++ b/Documentation/devicetree/bindings/arm/arm,mpam-msc.yaml > > > > @@ -0,0 +1,202 @@ > > > > +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause > > > > +%YAML 1.2 > > > > +--- > > > > +$id: http://devicetree.org/schemas/arm/arm,mpam-msc.yaml# > > > > +$schema: http://devicetree.org/meta-schemas/core.yaml# > > > > + > > > > +title: Arm Memory System Resource Partitioning and Monitoring (MPAM) > > > > + > > > > +maintainers: > > > > +  - Rob Herring > > > > + > > > > +description: | > > > > +  The Arm MPAM specification can be found here: > > > > + > > > > +  https://developer.arm.com/documentation/ddi0598/latest > > > > + > > > > +properties: > > > > +  compatible: > > > > +    oneOf: > > > > +      - const: arm,mpam-msc                   # Further details > > > > are discoverable > > > > +      - items: > > > > +          - const: arm,mpam-memory-controller-msc > > > > > > Why do we need this? > > > > > > > Hi Rob, > > > > Thanks for the review. > > > > The 'arm,mpam-memory-controller-msc' compatible is needed because, > > unlike cache MSCs, memory controller MSCs cannot rely on the parent node > > to identify the resource type. > > > > Cache controllers universally carry a 'cache' compatible, so the driver > > can recognise any cache parent and derive the cache ID from standard > > properties. No equivalent convention exists for memory controllers, and > > the component ID comes from the MSC's own 'numa-node-id' rather than the > > parent, so there is no parent attribute to rely on. > > > > Hi Rob, > > As a follow-up to my previous reply: > Whatever the outcome of the discussion on "arm_mpam: Add support for > memory controller MSC on DT platforms", we will keep the binding and > driver support consistent. If it's dropped, the > 'arm,mpam-memory-controller-msc' compatible, 'numa-node-id' property, and > the memory controller example will be removed together. Which parts are you actually using/needing and not using? If you don't need RIS support, for example, we should drop it. Rob