From patchwork Tue Apr 2 13:15:47 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: 10881691 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 B162B1669 for ; Tue, 2 Apr 2019 13:21:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 97E9E287C8 for ; Tue, 2 Apr 2019 13:21:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8BE2B288D3; Tue, 2 Apr 2019 13:21:31 +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=-5.2 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 21E21287C8 for ; Tue, 2 Apr 2019 13:21:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=y/Sf2s11WZB3CZGGnS1mePCINxitORWP5KWwl5u9j4A=; b=SZM8sKNOrgLGc9 iNBE/jkAKUu/tAnJW6WOgq8x/LHp7WgRS3dVsw8o2J7CCMrxGiRV9bjFIgdkvQ9UxpOzsOxn1HWnX 9doO3D9W/3S7uy/YtWjkxjIqugctqzQlchxjrtQciv3s/OoinBIzGTYsvevmCkRq+yU+tRk5ph7Eh zPXTMx51GOkRZEVSOLFxYaTsxZH3KxVWSSRbV5OmJyv8EMMxeKntb3H8GvWZv2rrmoqAggMsKHZpV QYJA9c8OdAlfPe5PS6uNaStpNibHZXEf9rx9dqpMCgvBB7HrvX5Gm5T/HRzemmhwFDetoVz0Lq6RQ oX+mJLrFVr6BH/R1TztQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hBJLw-0000ii-SI; Tue, 02 Apr 2019 13:21:24 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hBJLp-0000Yt-Ab for linux-arm-kernel@lists.infradead.org; Tue, 02 Apr 2019 13:21:18 +0000 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 EE5CE1993; Tue, 2 Apr 2019 06:21:14 -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 506E23F690; Tue, 2 Apr 2019 06:21:13 -0700 (PDT) From: Jean-Philippe Brucker To: bhelgaas@google.com, robh+dt@kernel.org, mark.rutland@arm.com Subject: [PATCH v2 1/2] dt-bindings: Add external-facing PCIe port property Date: Tue, 2 Apr 2019 14:15:47 +0100 Message-Id: <20190402131548.41949-2-jean-philippe.brucker@arm.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190402131548.41949-1-jean-philippe.brucker@arm.com> References: <20190402131548.41949-1-jean-philippe.brucker@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190402_062117_367487_0C862A6E X-CRM114-Status: GOOD ( 15.48 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, linux-pci@vger.kernel.org, Jeremy.Linton@arm.com, Grant.Likely@arm.com, Robin.Murphy@arm.com, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.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 user-accessible ports, which should always have the strongest IOMMU protection. Signed-off-by: Jean-Philippe Brucker Reviewed-by: Robin Murphy Reviewed-by: Rob Herring --- Documentation/devicetree/bindings/pci/pci.txt | 50 +++++++++++++++++++ 1 file changed, 50 insertions(+) diff --git a/Documentation/devicetree/bindings/pci/pci.txt b/Documentation/devicetree/bindings/pci/pci.txt index c77981c5dd18..92c01db610df 100644 --- a/Documentation/devicetree/bindings/pci/pci.txt +++ b/Documentation/devicetree/bindings/pci/pci.txt @@ -24,3 +24,53 @@ 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 +------------------------- + +PCIe 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. The OS can, for + example, use this information to identify devices that cannot be + trusted with relaxed DMA protection, as users could easily attach + malicious devices to this port. + +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; + }; +};