From patchwork Tue Jun 28 15:48:22 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Robin Murphy X-Patchwork-Id: 71097 Delivered-To: patch@linaro.org Received: by 10.140.28.4 with SMTP id 4csp1663023qgy; Tue, 28 Jun 2016 08:51:22 -0700 (PDT) X-Received: by 10.98.30.199 with SMTP id e190mr3061963pfe.146.1467129056964; Tue, 28 Jun 2016 08:50:56 -0700 (PDT) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id f15si34207340pap.97.2016.06.28.08.50.56; Tue, 28 Jun 2016 08:50:56 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of devicetree-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of devicetree-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=devicetree-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752020AbcF1Puy (ORCPT + 7 others); Tue, 28 Jun 2016 11:50:54 -0400 Received: from foss.arm.com ([217.140.101.70]:48421 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752101AbcF1Pux (ORCPT ); Tue, 28 Jun 2016 11:50:53 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 7762146E; Tue, 28 Jun 2016 08:51:45 -0700 (PDT) Received: from e104324-lin.cambridge.arm.com (e104324-lin.cambridge.arm.com [10.1.205.154]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id B53733F21A; Tue, 28 Jun 2016 08:50:51 -0700 (PDT) From: Robin Murphy To: will.deacon@arm.com, joro@8bytes.org, iommu@lists.linux-foundation.org Cc: lorenzo.pieralisi@arm.com, thunder.leizhen@huawei.com, jean-philippe.brucker@arm.com, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Mark Rutland Subject: [PATCH v3 3/9] Docs: dt: add PCI IOMMU map bindings Date: Tue, 28 Jun 2016 16:48:22 +0100 Message-Id: <274a234dcd7165cdbf1cc0bbc495b1a164ace14d.1467123945.git.robin.murphy@arm.com> X-Mailer: git-send-email 2.8.1.dirty In-Reply-To: References: Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org From: Mark Rutland The existing IOMMU bindings are able to specify the relationship between masters and IOMMUs, but they are insufficient for describing the general case of hotpluggable busses such as PCI where the set of masters is not known until runtime, and the relationship between masters and IOMMUs is a property of the integration of the system. This patch adds a generic binding for mapping PCI devices to IOMMUs, using a new iommu-map property (specific to PCI*) which may be used to map devices (identified by their Requester ID) to sideband data for the IOMMU which they master through. Acked-by: Rob Herring Acked-by: Will Deacon Signed-off-by: Mark Rutland --- v3: +Will's ack. .../devicetree/bindings/pci/pci-iommu.txt | 171 +++++++++++++++++++++ 1 file changed, 171 insertions(+) create mode 100644 Documentation/devicetree/bindings/pci/pci-iommu.txt -- 2.8.1.dirty -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/Documentation/devicetree/bindings/pci/pci-iommu.txt b/Documentation/devicetree/bindings/pci/pci-iommu.txt new file mode 100644 index 000000000000..56c829621b9a --- /dev/null +++ b/Documentation/devicetree/bindings/pci/pci-iommu.txt @@ -0,0 +1,171 @@ +This document describes the generic device tree binding for describing the +relationship between PCI(e) devices and IOMMU(s). + +Each PCI(e) device under a root complex is uniquely identified by its Requester +ID (AKA RID). A Requester ID is a triplet of a Bus number, Device number, and +Function number. + +For the purpose of this document, when treated as a numeric value, a RID is +formatted such that: + +* Bits [15:8] are the Bus number. +* Bits [7:3] are the Device number. +* Bits [2:0] are the Function number. +* Any other bits required for padding must be zero. + +IOMMUs may distinguish PCI devices through sideband data derived from the +Requester ID. While a given PCI device can only master through one IOMMU, a +root complex may split masters across a set of IOMMUs (e.g. with one IOMMU per +bus). + +The generic 'iommus' property is insufficient to describe this relationship, +and a mechanism is required to map from a PCI device to its IOMMU and sideband +data. + +For generic IOMMU bindings, see +Documentation/devicetree/bindings/iommu/iommu.txt. + + +PCI root complex +================ + +Optional properties +------------------- + +- iommu-map: Maps a Requester ID to an IOMMU and associated iommu-specifier + data. + + The property is an arbitrary number of tuples of + (rid-base,iommu,iommu-base,length). + + Any RID r in the interval [rid-base, rid-base + length) is associated with + the listed IOMMU, with the iommu-specifier (r - rid-base + iommu-base). + +- iommu-map-mask: A mask to be applied to each Requester ID prior to being + mapped to an iommu-specifier per the iommu-map property. + + +Example (1) +=========== + +/ { + #address-cells = <1>; + #size-cells = <1>; + + iommu: iommu@a { + reg = <0xa 0x1>; + compatible = "vendor,some-iommu"; + #iommu-cells = <1>; + }; + + pci: pci@f { + reg = <0xf 0x1>; + compatible = "vendor,pcie-root-complex"; + device_type = "pci"; + + /* + * The sideband data provided to the IOMMU is the RID, + * identity-mapped. + */ + iommu-map = <0x0 &iommu 0x0 0x10000>; + }; +}; + + +Example (2) +=========== + +/ { + #address-cells = <1>; + #size-cells = <1>; + + iommu: iommu@a { + reg = <0xa 0x1>; + compatible = "vendor,some-iommu"; + #iommu-cells = <1>; + }; + + pci: pci@f { + reg = <0xf 0x1>; + compatible = "vendor,pcie-root-complex"; + device_type = "pci"; + + /* + * The sideband data provided to the IOMMU is the RID with the + * function bits masked out. + */ + iommu-map = <0x0 &iommu 0x0 0x10000>; + iommu-map-mask = <0xfff8>; + }; +}; + + +Example (3) +=========== + +/ { + #address-cells = <1>; + #size-cells = <1>; + + iommu: iommu@a { + reg = <0xa 0x1>; + compatible = "vendor,some-iommu"; + #iommu-cells = <1>; + }; + + pci: pci@f { + reg = <0xf 0x1>; + compatible = "vendor,pcie-root-complex"; + device_type = "pci"; + + /* + * The sideband data provided to the IOMMU is the RID, + * but the high bits of the bus number are flipped. + */ + iommu-map = <0x0000 &iommu 0x8000 0x8000>, + <0x8000 &iommu 0x0000 0x8000>; + }; +}; + + +Example (4) +=========== + +/ { + #address-cells = <1>; + #size-cells = <1>; + + iommu_a: iommu@a { + reg = <0xa 0x1>; + compatible = "vendor,some-iommu"; + #iommu-cells = <1>; + }; + + iommu_b: iommu@b { + reg = <0xb 0x1>; + compatible = "vendor,some-iommu"; + #iommu-cells = <1>; + }; + + iommu_c: iommu@c { + reg = <0xc 0x1>; + compatible = "vendor,some-iommu"; + #iommu-cells = <1>; + }; + + pci: pci@f { + reg = <0xf 0x1>; + compatible = "vendor,pcie-root-complex"; + device_type = "pci"; + + /* + * Devices with bus number 0-127 are mastered via IOMMU + * a, with sideband data being RID[14:0]. + * Devices with bus number 128-255 are mastered via + * IOMMU b, with sideband data being RID[14:0]. + * No devices master via IOMMU c. + */ + iommu-map = <0x0000 &iommu_a 0x0000 0x8000>, + <0x8000 &iommu_b 0x0000 0x8000>; + }; +};