From patchwork Thu Jun 11 13:05:25 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kishon Vijay Abraham I X-Patchwork-Id: 11600093 X-Patchwork-Delegate: lorenzo.pieralisi@arm.com Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0067190 for ; Thu, 11 Jun 2020 13:06:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D59B9207ED for ; Thu, 11 Jun 2020 13:06:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b="Lk7WX+WM" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728289AbgFKNGu (ORCPT ); Thu, 11 Jun 2020 09:06:50 -0400 Received: from lelv0142.ext.ti.com ([198.47.23.249]:56618 "EHLO lelv0142.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728282AbgFKNGr (ORCPT ); Thu, 11 Jun 2020 09:06:47 -0400 Received: from lelv0265.itg.ti.com ([10.180.67.224]) by lelv0142.ext.ti.com (8.15.2/8.15.2) with ESMTP id 05BD6Y4j085542; Thu, 11 Jun 2020 08:06:34 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1591880794; bh=gIasfhB7kWsDgMz33iBPDD5XtaEwVi4iD+o+7fTFAb4=; h=From:To:CC:Subject:Date:In-Reply-To:References; b=Lk7WX+WMQUDt2GH7O3S/FT3qau4RwbWAPEVGrjAsttVwykFM/Uaxxixy2z+weyXLe ERbOTbHkpq+2Ufe+BxFbSpbXyDhcJduveCJ2oHdEhgW57CDyUe0ZQ86WDn/CwHrNWt YRBwjxpnYdAtQdauKIUD7WQ1meH8nuvptd+o1Qos= Received: from DLEE102.ent.ti.com (dlee102.ent.ti.com [157.170.170.32]) by lelv0265.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 05BD6YA8058925 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 11 Jun 2020 08:06:34 -0500 Received: from DLEE105.ent.ti.com (157.170.170.35) by DLEE102.ent.ti.com (157.170.170.32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1979.3; Thu, 11 Jun 2020 08:06:33 -0500 Received: from lelv0327.itg.ti.com (10.180.67.183) by DLEE105.ent.ti.com (157.170.170.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1979.3 via Frontend Transport; Thu, 11 Jun 2020 08:06:33 -0500 Received: from a0393678ub.india.ti.com (ileax41-snat.itg.ti.com [10.172.224.153]) by lelv0327.itg.ti.com (8.15.2/8.15.2) with ESMTP id 05BD5PZF082585; Thu, 11 Jun 2020 08:06:29 -0500 From: Kishon Vijay Abraham I To: Bjorn Helgaas , Jonathan Corbet , Kishon Vijay Abraham I , Lorenzo Pieralisi , Arnd Bergmann , Jon Mason , Dave Jiang , Allen Hubbe , Tom Joseph , Rob Herring CC: Greg Kroah-Hartman , , , , Subject: [PATCH v2 14/14] Documentation: PCI: Add userguide for PCI endpoint NTB function Date: Thu, 11 Jun 2020 18:35:25 +0530 Message-ID: <20200611130525.22746-15-kishon@ti.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200611130525.22746-1-kishon@ti.com> References: <20200611130525.22746-1-kishon@ti.com> MIME-Version: 1.0 X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Add documentation to help users use pci-epf-ntb function driver and existing host side NTB infrastructure for NTB functionality. Signed-off-by: Kishon Vijay Abraham I --- Documentation/PCI/endpoint/index.rst | 1 + Documentation/PCI/endpoint/pci-ntb-howto.rst | 141 +++++++++++++++++++ 2 files changed, 142 insertions(+) create mode 100644 Documentation/PCI/endpoint/pci-ntb-howto.rst diff --git a/Documentation/PCI/endpoint/index.rst b/Documentation/PCI/endpoint/index.rst index ae6d25621058..74aa7e713299 100644 --- a/Documentation/PCI/endpoint/index.rst +++ b/Documentation/PCI/endpoint/index.rst @@ -12,3 +12,4 @@ PCI Endpoint Framework pci-test-function pci-test-howto pci-ntb-function + pci-ntb-howto diff --git a/Documentation/PCI/endpoint/pci-ntb-howto.rst b/Documentation/PCI/endpoint/pci-ntb-howto.rst new file mode 100644 index 000000000000..88a672c7d6ca --- /dev/null +++ b/Documentation/PCI/endpoint/pci-ntb-howto.rst @@ -0,0 +1,141 @@ +.. SPDX-License-Identifier: GPL-2.0 + +====================== +PCI NTB EPF User Guide +====================== + +:Author: Kishon Vijay Abraham I + +This document is a guide to help users use pci-epf-ntb function driver +and ntb_hw_epf host driver for NTB functionality. The list of steps to +be followed in the host side and EP side is given below. For the hardware +configuration and internals of NTB using configurable endpoints see +Documentation/PCI/endpoint/pci-ntb-function.rst + +Endpoint Device +=============== + +Endpoint Controller Devices +--------------------------- + +For implementing NTB functionality atleast two endpoint controller devices +are required. +To find the list of endpoint controller devices in the system:: + + # ls /sys/class/pci_epc/ + 2900000.pcie-ep 2910000.pcie-ep + +If PCI_ENDPOINT_CONFIGFS is enabled:: + + # ls /sys/kernel/config/pci_ep/controllers + 2900000.pcie-ep 2910000.pcie-ep + + +Endpoint Function Drivers +------------------------- + +To find the list of endpoint function drivers in the system:: + + # ls /sys/bus/pci-epf/drivers + pci_epf_ntb pci_epf_ntb + +If PCI_ENDPOINT_CONFIGFS is enabled:: + + # ls /sys/kernel/config/pci_ep/functions + pci_epf_ntb pci_epf_ntb + + +Creating pci-epf-ntb Device +---------------------------- + +PCI endpoint function device can be created using the configfs. To create +pci-epf-ntb device, the following commands can be used:: + + # mount -t configfs none /sys/kernel/config + # cd /sys/kernel/config/pci_ep/ + # mkdir functions/pci_epf_ntb/func1 + +The "mkdir func1" above creates the pci-epf-ntb function device that will +be probed by pci_epf_ntb driver. + +The PCI endpoint framework populates the directory with the following +configurable fields:: + + # ls functions/pci_epf_ntb/func1 + baseclass_code deviceid msi_interrupts pci-epf-ntb.0 + progif_code secondary subsys_id vendorid + cache_line_size interrupt_pin msix_interrupts primary + revid subclass_code subsys_vendor_id + +The PCI endpoint function driver populates these entries with default values +when the device is bound to the driver. The pci-epf-ntb driver populates +vendorid with 0xffff and interrupt_pin with 0x0001:: + + # cat functions/pci_epf_ntb/func1/vendorid + 0xffff + # cat functions/pci_epf_ntb/func1/interrupt_pin + 0x0001 + + +Configuring pci-epf-ntb Device +------------------------------- + +The user can configure the pci-epf-ntb device using configfs entry. In order +to change the vendorid and the number of MSI interrupts device, the following +commands can be used:: + + # echo 0x104c > functions/pci_epf_ntb/func1/vendorid + # echo 0xb00d > functions/pci_epf_ntb/func1/deviceid + + +Binding pci-epf-ntb Device to EP Controller +-------------------------------------------- + +NTB function device should be attached to two PCIe endpoint controllers +connected to the two hosts. Use the 'primary' and 'secondary' entries +inside NTB function device to attach one PCIe endpoint controller to +primary interface and the other PCIe endpoint controller to the secondary +interface. :: + + # ln -s controllers/2900000.pcie-ep/ functions/pci-epf-ntb/func1/primary + # ln -s controllers/2910000.pcie-ep/ functions/pci-epf-ntb/func1/secondary + +Once the above step is completed, both the PCI endpoint controllers is ready to +establish a link with the host. + + +Start the Link +-------------- + +In order for the endpoint device to establish a link with the host, the _start_ +field should be populated with '1'. For NTB, both the PCIe endpoint controllers +should establish link with the host:: + + #echo 1 > controllers/2900000.pcie-ep/start + #echo 1 > controllers/2910000.pcie-ep/start + + +RootComplex Device +================== + +lspci Output +------------ + +Note that the devices listed here correspond to the value populated in 1.4 +above:: + + # lspci + 0000:00:00.0 PCI bridge: Texas Instruments Device b00d + 0000:01:00.0 RAM memory: Texas Instruments Device b00d + + +Using ntb_hw_epf Device +----------------------- + +The host side software follows the standard NTB software architecture in Linux. +All the existing client side NTB utilities like NTB Transport Client and NTB +Netdev, NTB Ping Pong Test Client and NTB Tool Test Clientcan be used with NTB +function device. + +For more information on NTB see +Documentation/driver-api/ntb.rst