From patchwork Thu Sep 24 09:25:19 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: 11796723 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 40C47139A for ; Thu, 24 Sep 2020 09:27:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0FC7B2311A for ; Thu, 24 Sep 2020 09:27:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b="vRCJsO7e" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727700AbgIXJ1O (ORCPT ); Thu, 24 Sep 2020 05:27:14 -0400 Received: from fllv0016.ext.ti.com ([198.47.19.142]:58366 "EHLO fllv0016.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727673AbgIXJ1G (ORCPT ); Thu, 24 Sep 2020 05:27:06 -0400 Received: from fllv0034.itg.ti.com ([10.64.40.246]) by fllv0016.ext.ti.com (8.15.2/8.15.2) with ESMTP id 08O9QsgZ117851; Thu, 24 Sep 2020 04:26:54 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1600939614; bh=4Fz6/znawPVT5Re4ej/ysxXwiAWhNVKJ7aypY2BXCzQ=; h=From:To:CC:Subject:Date:In-Reply-To:References; b=vRCJsO7eyzJG7pA/GdGBWLJUqOHCzDJcbgiX9Ido+QAG+apgnlhn4ZdKiS7pVdEBx GSnw5auHURVJjB7hZQxyNHgg880sMqlsamli42SNy+r+v8yAIYhpGi0wWe/Rim9/Q5 0oei4PcuMhXHvGIHhPPQW1cIs6nHK7yAuVRmOXsg= Received: from DFLE106.ent.ti.com (dfle106.ent.ti.com [10.64.6.27]) by fllv0034.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 08O9Qspg036981 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 24 Sep 2020 04:26:54 -0500 Received: from DFLE114.ent.ti.com (10.64.6.35) by DFLE106.ent.ti.com (10.64.6.27) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1979.3; Thu, 24 Sep 2020 04:26:54 -0500 Received: from fllv0039.itg.ti.com (10.64.41.19) by DFLE114.ent.ti.com (10.64.6.35) 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, 24 Sep 2020 04:26:54 -0500 Received: from a0393678-ssd.dal.design.ti.com (ileax41-snat.itg.ti.com [10.172.224.153]) by fllv0039.itg.ti.com (8.15.2/8.15.2) with ESMTP id 08O9POZ6011000; Thu, 24 Sep 2020 04:26:49 -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 v6 17/17] Documentation: PCI: Add userguide for PCI endpoint NTB function Date: Thu, 24 Sep 2020 14:55:19 +0530 Message-ID: <20200924092519.17082-18-kishon@ti.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200924092519.17082-1-kishon@ti.com> References: <20200924092519.17082-1-kishon@ti.com> MIME-Version: 1.0 X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 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 Reviewed-by: Randy Dunlap --- Documentation/PCI/endpoint/index.rst | 1 + Documentation/PCI/endpoint/pci-ntb-howto.rst | 160 +++++++++++++++++++ 2 files changed, 161 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 9cb6e5f3c4d5..38ea1f604b6d 100644 --- a/Documentation/PCI/endpoint/index.rst +++ b/Documentation/PCI/endpoint/index.rst @@ -12,6 +12,7 @@ PCI Endpoint Framework pci-test-function pci-test-howto pci-ntb-function + pci-ntb-howto function/binding/pci-test function/binding/pci-ntb diff --git a/Documentation/PCI/endpoint/pci-ntb-howto.rst b/Documentation/PCI/endpoint/pci-ntb-howto.rst new file mode 100644 index 000000000000..b6e1073c9a39 --- /dev/null +++ b/Documentation/PCI/endpoint/pci-ntb-howto.rst @@ -0,0 +1,160 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=================================================================== +PCI Non-Transparent Bridge (NTB) Endpoint Function (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 at least 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 its configfs entry. In order +to change the vendorid and the deviceid, the following +commands can be used:: + + # echo 0x104c > functions/pci_epf_ntb/func1/vendorid + # echo 0xb00d > functions/pci_epf_ntb/func1/deviceid + +In order to configure NTB specific attributes, a new sub-directory to func1 +should be created:: + + # mkdir functions/pci_epf_ntb/func1/pci_epf_ntb.0/ + +The NTB function driver will populate this directory with various attributes +that can be configured by the user:: + + # ls functions/pci_epf_ntb/func1/pci_epf_ntb.0/ + db_count mw1 mw2 mw3 mw4 num_mws + spad_count + +A sample configuration for NTB function is given below:: + + # echo 4 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/db_count + # echo 128 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/spad_count + # echo 2 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/num_mws + # echo 0x100000 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/mw1 + # echo 0x100000 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/mw2 + +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 are 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 values populated in +"Creating pci-epf-ntb Device" section 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 Client can be used with NTB +function device. + +For more information on NTB see +:doc:`Non-Transparent Bridge <../../driver-api/ntb>`