From patchwork Mon Feb 1 05:38:03 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xu Yilun X-Patchwork-Id: 12058109 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=-16.7 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=unavailable 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 CE1F2C433DB for ; Mon, 1 Feb 2021 05:48:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8AAF864E15 for ; Mon, 1 Feb 2021 05:48:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231571AbhBAFra (ORCPT ); Mon, 1 Feb 2021 00:47:30 -0500 Received: from mga11.intel.com ([192.55.52.93]:18860 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229917AbhBAFpW (ORCPT ); Mon, 1 Feb 2021 00:45:22 -0500 IronPort-SDR: L8tueSMKodp4mWVDM79ITvmVwqwJgOdXTR3ab7B3e2O7tmI+6GEugh9Lc6gRLLpcJI5Q4Il/C2 u6RHigW27/Sw== X-IronPort-AV: E=McAfee;i="6000,8403,9881"; a="177129268" X-IronPort-AV: E=Sophos;i="5.79,391,1602572400"; d="scan'208";a="177129268" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Jan 2021 21:42:48 -0800 IronPort-SDR: PLphEVLiZVB9bAjv1uXDE6J3QX7nlD9kyHW+EUhi0kqwN0sytb+TZSxJTiQwTflZIgck05kJgU yproivahxrbg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.79,391,1602572400"; d="scan'208";a="368973525" Received: from yilunxu-optiplex-7050.sh.intel.com ([10.239.159.141]) by fmsmga008.fm.intel.com with ESMTP; 31 Jan 2021 21:42:46 -0800 From: Xu Yilun To: gregkh@linuxfoundation.org, mdf@kernel.org, linux-fpga@vger.kernel.org, linux-kernel@vger.kernel.org Cc: trix@redhat.com, lgoncalv@redhat.com, yilun.xu@intel.com, hao.wu@intel.com Subject: [PATCH v10 2/2] Documentation: fpga: dfl: Add description for DFL UIO support Date: Mon, 1 Feb 2021 13:38:03 +0800 Message-Id: <1612157883-18616-3-git-send-email-yilun.xu@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1612157883-18616-1-git-send-email-yilun.xu@intel.com> References: <1612157883-18616-1-git-send-email-yilun.xu@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-fpga@vger.kernel.org This patch adds description for UIO support for dfl devices on DFL bus. Signed-off-by: Xu Yilun Reviewed-by: Tom Rix --- v2: no doc in v1, add it for v2. v3: some documentation fixes. v4: documentation change since the driver matching is changed. v5: no change. v6: improve the title of the userspace driver support section. some word improvement. v7: rebased to next-20210119 v8: some doc fixes. v9: some doc change since we switch to the driver in drivers/uio. v10: no change. --- Documentation/fpga/dfl.rst | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/Documentation/fpga/dfl.rst b/Documentation/fpga/dfl.rst index c41ac76..e35cf87 100644 --- a/Documentation/fpga/dfl.rst +++ b/Documentation/fpga/dfl.rst @@ -7,6 +7,7 @@ Authors: - Enno Luebbers - Xiao Guangrong - Wu Hao +- Xu Yilun The Device Feature List (DFL) FPGA framework (and drivers according to this framework) hides the very details of low layer hardwares and provides @@ -530,6 +531,28 @@ Being able to specify more than one DFL per BAR has been considered, but it was determined the use case did not provide value. Specifying a single DFL per BAR simplifies the implementation and allows for extra error checking. + +Userspace driver support for DFL devices +======================================== +The purpose of an FPGA is to be reprogrammed with newly developed hardware +components. New hardware can instantiate a new private feature in the DFL, and +then present a DFL device in the system. In some cases users may need a +userspace driver for the DFL device: + +* Users may need to run some diagnostic test for their hardware. +* Users may prototype the kernel driver in user space. +* Some hardware is designed for specific purposes and does not fit into one of + the standard kernel subsystems. + +This requires direct access to MMIO space and interrupt handling from +userspace. The uio_dfl module exposes the UIO device interfaces for this +purpose. + +UIO_DFL should be selected to enable the uio_dfl module driver. To support a +new DFL feature via UIO direct access, its feature id should be added to the +driver's id_table. + + Open discussion =============== FME driver exports one ioctl (DFL_FPGA_FME_PORT_PR) for partial reconfiguration