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=-17.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 76C88C2D0E4 for ; Fri, 18 Dec 2020 23:00:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3523C23B28 for ; Fri, 18 Dec 2020 23:00:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726209AbgLRW74 (ORCPT ); Fri, 18 Dec 2020 17:59:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53676 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725957AbgLRW74 (ORCPT ); Fri, 18 Dec 2020 17:59:56 -0500 Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2412EC0617B0; Fri, 18 Dec 2020 14:59:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To:Subject:Sender :Reply-To:Content-ID:Content-Description; bh=wZt5jPkvDSYDw1XVc5r0R9C+AIg9SwGtTG0KRX6U9Fw=; b=QEbvfz27RCcd47U1jfTFu5wjHF 4qNrQqRDEK5VTtx69yxp0uca/x1i6r9+kRqjPkjZftduHIf+VdopkauCB7Ww9g6F+2u0nb0a2xbsz TitDRYLBtxSeliJzCYqNRsW5VgY3ze4qHi3BjDyfzX/+k7ZTgYozobXyabbc1Ij7lbF1/KdIEnoJN Mlqm3JFUE6TfwAf6/W1+zPyCRpCnC/kEPiXr45t0Vun8wHAoGmvxWcbbqkVLTt3Zg9o70sHHEZU75 JSuQ3kzfeoJtc48tlp0LffA6kiT8Z43g2bNyHQ/KUoCqcpnRB9VYOq5uuhKcb45uMP37GlZmGrGZH QHjumSnw==; Received: from [2601:1c0:6280:3f0::64ea] by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kqOiK-0005zy-Kx; Fri, 18 Dec 2020 22:59:09 +0000 Subject: Re: [PATCH 06/22] misc: xlink-pcie: Add documentation for XLink PCIe driver To: mgross@linux.intel.com, markgross@kernel.org, arnd@arndb.de, bp@suse.de, damien.lemoal@wdc.com, dragan.cvetic@xilinx.com, gregkh@linuxfoundation.org, corbet@lwn.net, leonard.crestez@nxp.com, palmerdabbelt@google.com, paul.walmsley@sifive.com, peng.fan@nxp.com, robh+dt@kernel.org, shawnguo@kernel.org Cc: linux-kernel@vger.kernel.org, Srikanth Thokala , linux-doc@vger.kernel.org References: <20201201223511.65542-1-mgross@linux.intel.com> <20201201223511.65542-7-mgross@linux.intel.com> From: Randy Dunlap Message-ID: <2fd73da0-ee89-3831-bf96-5ed130e90c4d@infradead.org> Date: Fri, 18 Dec 2020 14:59:00 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: <20201201223511.65542-7-mgross@linux.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On 12/1/20 2:34 PM, mgross@linux.intel.com wrote: > From: Srikanth Thokala > > Provide overview of XLink PCIe driver implementation > > 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 > Hi-- For document, chapter, section, etc., headings, please read & use Documentation/doc-guide/sphinx.rst: * Please stick to this order of heading adornments: 1. ``=`` with overline for document title:: ============== Document title ============== 2. ``=`` for chapters:: Chapters ======== 3. ``-`` for sections:: Section ------- 4. ``~`` for subsections:: Subsection ~~~~~~~~~~ > 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: No colon at end of chapter/section headings. > +------------- > +The xlink-pcie driver in linux-5.4 provides transport layer implementation for Linux 5.4 (?) > +the data transfers to support xlink protocol subsystem communication with the Xlink > +peer device. i.e, between remote host system and the local Keem Bay device. device, i.e., between the remote host system and > + > +The Keem Bay device is an ARM based SOC that includes a vision processing ARM-based > +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. with the 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 registers the > +and provides standard linux pcie sysfs interface, # /sys/bus/pci/devices/xxxx:xx:xx.0/ Linux PCIe > + > + > +------------------------- > +XLink protocol subsystem: No colon at end. > +------------------------- > +xlink is an abstracted control and communication subsystem based on channel Xlink > +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 Xlink > + 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 Xlink > + from standalone local system or from remote system based on communication > + interface underneath. > +- The xlink subsystem supports following communication interfaces: Xlink supports the following > + * USB CDC > + * Gigabit Ethernet > + * PCIe > + * IPC > cheers. -- ~Randy