From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0693FC71156 for ; Mon, 30 Nov 2020 23:08:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BF6722076C for ; Mon, 30 Nov 2020 23:08:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730987AbgK3XIb (ORCPT ); Mon, 30 Nov 2020 18:08:31 -0500 Received: from mga14.intel.com ([192.55.52.115]:58436 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730973AbgK3XI2 (ORCPT ); Mon, 30 Nov 2020 18:08:28 -0500 IronPort-SDR: 419mN7z4MA2W0dBH5XiYcsBB61LcbK3pBzdachodZfR6dzQMhpKnqR0DjQoC7W4Fc/FunoRvPr Qwb6yU4+P92w== X-IronPort-AV: E=McAfee;i="6000,8403,9821"; a="171941906" X-IronPort-AV: E=Sophos;i="5.78,382,1599548400"; d="scan'208";a="171941906" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Nov 2020 15:07:10 -0800 IronPort-SDR: k/T3wces5yNnvKRppoMBqMuuEDUqJZdv714T9Uq/1ObRlyuq167BbGBbsiXeMPpWx1nCC0as9q /oTuUneR8VKA== X-IronPort-AV: E=Sophos;i="5.78,382,1599548400"; d="scan'208";a="364436857" Received: from smtp.ostc.intel.com ([10.54.29.231]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Nov 2020 15:07:10 -0800 Received: from mtg-dev (mtg-dev.jf.intel.com [10.54.74.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.ostc.intel.com (Postfix) with ESMTPS id 0FC5C636D; Mon, 30 Nov 2020 15:07:10 -0800 (PST) Received: from mgross by mtg-dev with local (Exim 4.90_1) (envelope-from ) id 1kjsGD-000C4z-Ta; Mon, 30 Nov 2020 15:07:09 -0800 From: mgross@linux.intel.com To: linux-kernel@vger.kernel.org Cc: markgross@kernel.org, mgross@linux.intel.com, adam.r.gretzinger@intel.com, Srikanth Thokala , Jonathan Corbet , linux-doc@vger.kernel.org Subject: [PATCH 06/22] misc: xlink-pcie: Add documentation for XLink PCIe driver Date: Mon, 30 Nov 2020 15:06:51 -0800 Message-Id: <20201130230707.46351-7-mgross@linux.intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201130230707.46351-1-mgross@linux.intel.com> References: <20201130230707.46351-1-mgross@linux.intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Srikanth Thokala Provide overview of XLink PCIe driver implementation Cc: Jonathan Corbet Cc: linux-doc@vger.kernel.org Reviewed-by: Mark Gross Signed-off-by: Srikanth Thokala --- Documentation/vpu/index.rst | 1 + Documentation/vpu/xlink-pcie.rst | 91 ++++++++++++++++++++++++++++++++ 2 files changed, 92 insertions(+) create mode 100644 Documentation/vpu/xlink-pcie.rst diff --git a/Documentation/vpu/index.rst b/Documentation/vpu/index.rst index 7e290e048910..661cc700ee45 100644 --- a/Documentation/vpu/index.rst +++ b/Documentation/vpu/index.rst @@ -14,3 +14,4 @@ This documentation contains information for the Intel VPU stack. :maxdepth: 2 vpu-stack-overview + xlink-pcie diff --git a/Documentation/vpu/xlink-pcie.rst b/Documentation/vpu/xlink-pcie.rst new file mode 100644 index 000000000000..bc64b566989d --- /dev/null +++ b/Documentation/vpu/xlink-pcie.rst @@ -0,0 +1,91 @@ +.. SPDX-License-Identifier: GPL-2.0-only + +Kernel driver: xlink-pcie driver +================================ +Supported chips: + * Intel Edge.AI Computer Vision platforms: Keem Bay + Suffix: Bay + Slave address: 6240 + Datasheet: Publicly available at Intel + +Author: Srikanth Thokala Srikanth.Thokala@intel.com + +------------- +Introduction: +------------- +The xlink-pcie driver in linux-5.4 provides transport layer implementation for +the data transfers to support xlink protocol subsystem communication with the +peer device. i.e, between remote host system and the local Keem Bay device. + +The Keem Bay device is an ARM based SOC that includes a vision processing +unit (VPU) and deep learning, neural network core in the hardware. +The xlink-pcie driver exports a functional device endpoint to the Keem Bay device +and supports two-way communication with peer device. + +------------------------ +High-level architecture: +------------------------ +Remote Host: IA CPU +Local Host: ARM CPU (Keem Bay):: + + +------------------------------------------------------------------------+ + | Remote Host IA CPU | | Local Host ARM CPU (Keem Bay) | | + +==================================+=+===============================+===+ + | User App | | User App | | + +----------------------------------+-+-------------------------------+---+ + | XLink UAPI | | XLink UAPI | | + +----------------------------------+-+-------------------------------+---+ + | XLink Core | | XLink Core | | + +----------------------------------+-+-------------------------------+---+ + | XLink PCIe | | XLink PCIe | | + +----------------------------------+-+-------------------------------+---+ + | XLink-PCIe Remote Host driver | | XLink-PCIe Local Host driver | | + +----------------------------------+-+-------------------------------+---+ + |-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:|:|:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:| + +----------------------------------+-+-------------------------------+---+ + | PCIe Host Controller | | PCIe Device Controller | HW| + +----------------------------------+-+-------------------------------+---+ + ^ ^ + | | + |------------- PCIe x2 Link -----------------| + +This XLink PCIe driver comprises of two variants: +* Local Host driver + + * Intended for ARM CPU + * It is based on PCI Endpoint Framework + * Driver path: {tree}/drivers/misc/xlink-pcie/local_host + +* Remote Host driver + + * Intended for IA CPU + * It is a PCIe endpoint driver + * Driver path: {tree}/drivers/misc/xlink-pcie/remote_host + +XLink PCIe communication between local host and remote host is achieved through +ring buffer management and MSI/Doorbell interrupts. + +The xlink-pcie driver subsystem registers Keem Bay device as an endpoint driver +and provides standard linux pcie sysfs interface, # /sys/bus/pci/devices/xxxx:xx:xx.0/ + + +------------------------- +XLink protocol subsystem: +------------------------- +xlink is an abstracted control and communication subsystem based on channel +identification. It is intended to support VPU technology both at SoC level as +well as at IP level, over multiple interfaces. + +- The xlink subsystem abstracts several types of communication channels + underneath, allowing the usage of different interfaces with the + same function call interface. +- The Communication channels are full-duplex protocol channels allowing + concurrent bidirectional communication. +- The xlink subsystem also supports control operations to VPU either + from standalone local system or from remote system based on communication + interface underneath. +- The xlink subsystem supports following communication interfaces: + * USB CDC + * Gigabit Ethernet + * PCIe + * IPC -- 2.17.1