From patchwork Mon Mar 18 18:21:23 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jean-Philippe Brucker X-Patchwork-Id: 10858379 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 4C21E14DE for ; Mon, 18 Mar 2019 18:24:46 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 349A12949B for ; Mon, 18 Mar 2019 18:24:46 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 290D52949A; Mon, 18 Mar 2019 18:24:46 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B644A28CC9 for ; Mon, 18 Mar 2019 18:24:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726765AbfCRSYp (ORCPT ); Mon, 18 Mar 2019 14:24:45 -0400 Received: from foss.arm.com ([217.140.101.70]:39494 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726828AbfCRSYo (ORCPT ); Mon, 18 Mar 2019 14:24:44 -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 72170165C; Mon, 18 Mar 2019 11:24:44 -0700 (PDT) Received: from ostrya.cambridge.arm.com (ostrya.cambridge.arm.com [10.1.196.129]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id C94783F614; Mon, 18 Mar 2019 11:24:42 -0700 (PDT) From: Jean-Philippe Brucker To: bhelgaas@google.com, robh+dt@kernel.org, mark.rutland@arm.com Cc: linux-pci@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Grant.Likely@arm.com, Jeremy.Linton@arm.com, Robin.Murphy@arm.com Subject: [PATCH 1/2] dt-bindings: Add external-facing PCIe port property Date: Mon, 18 Mar 2019 18:21:23 +0000 Message-Id: <20190318182124.53859-2-jean-philippe.brucker@arm.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190318182124.53859-1-jean-philippe.brucker@arm.com> References: <20190318182124.53859-1-jean-philippe.brucker@arm.com> MIME-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Provide a way for the firmware to tell the OS which devices are external to the machine and therefore untrusted. The property can describe for example thunderbolt and other hot-pluggable ports, which should always have the strongest IOMMU protection. Signed-off-by: Jean-Philippe Brucker --- Documentation/devicetree/bindings/pci/pci.txt | 47 +++++++++++++++++++ 1 file changed, 47 insertions(+) diff --git a/Documentation/devicetree/bindings/pci/pci.txt b/Documentation/devicetree/bindings/pci/pci.txt index c77981c5dd18..55cdbc5d2804 100644 --- a/Documentation/devicetree/bindings/pci/pci.txt +++ b/Documentation/devicetree/bindings/pci/pci.txt @@ -24,3 +24,50 @@ driver implementation may support the following properties: unsupported link speed, for instance, trying to do training for unsupported link speed, etc. Must be '4' for gen4, '3' for gen3, '2' for gen2, and '1' for gen1. Any other values are invalid. + +PCI-PCI Bridge properties +------------------------- + +Root ports and switch ports may be described explicitly in the device +tree, as children of the host bridge node. Even though those devices are +discoverable by probing, it might be necessary to describe properties that +aren't provided by standard PCIe capabilities. + +Required properties: + +- reg: + Identifies the PCI-PCI bridge. As defined in the IEEE Std 1275-1994 + document, it is a five-cell address encoded as (phys.hi phys.mid + phys.lo size.hi size.lo). phys.hi should contain the device's BDF as + 0b00000000 bbbbbbbb dddddfff 00000000. The other cells should be zero. + + The bus number is defined by firmware, through the standard bridge + configuration mechanism. If this port is a switch port, then firmware + allocates the bus number and writes it into the Secondary Bus Number + register of the bridge directly above this port. Otherwise, the bus + number of a root port is the first number in the bus-range property, + defaulting to zero. + + If firmware leaves the ARI Forwarding Enable bit set in the bridge + above this port, then phys.hi contains the 8-bit function number as + 0b00000000 bbbbbbbb ffffffff 00000000. Note that the PCIe specification + recommends that firmware only leaves ARI enabled when it knows that the + OS is ARI-aware. + +Optional properties: + +- external-facing: + When present, the port is external facing. All bridges and endpoints + downstream of this port are external to the machine. + +Example: + +pcie@10000000 { + compatible = "pci-host-ecam-generic"; + ... + pcie@0008 { + /* Root port 00:01.0 is external-facing */ + reg = <0x00000800 0 0 0 0>; + external-facing; + }; +};