From patchwork Thu Sep 2 19:50:06 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ben Widawsky X-Patchwork-Id: 12472411 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,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 E58C9C4332F for ; Thu, 2 Sep 2021 19:50:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BC7B360FDC for ; Thu, 2 Sep 2021 19:50:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231467AbhIBTva (ORCPT ); Thu, 2 Sep 2021 15:51:30 -0400 Received: from mga12.intel.com ([192.55.52.136]:41967 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231476AbhIBTvY (ORCPT ); Thu, 2 Sep 2021 15:51:24 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10095"; a="198778194" X-IronPort-AV: E=Sophos;i="5.85,263,1624345200"; d="scan'208";a="198778194" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Sep 2021 12:50:24 -0700 X-IronPort-AV: E=Sophos;i="5.85,263,1624345200"; d="scan'208";a="533451605" Received: from kappusam-mobl.amr.corp.intel.com (HELO bad-guy.kumite) ([10.252.143.117]) by fmsmga003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Sep 2021 12:50:23 -0700 From: Ben Widawsky To: linux-cxl@vger.kernel.org Cc: Ben Widawsky , Alison Schofield , Dan Williams , Ira Weiny , Jonathan Cameron , Vishal Verma Subject: [PATCH 02/13] cxl/core/bus: Add kernel docs for decoder ops Date: Thu, 2 Sep 2021 12:50:06 -0700 Message-Id: <20210902195017.2516472-3-ben.widawsky@intel.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210902195017.2516472-1-ben.widawsky@intel.com> References: <20210902195017.2516472-1-ben.widawsky@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-cxl@vger.kernel.org Since the code to add decoders for switches and endpoints is on the horizon, document the new interfaces that will be consumed by them. Signed-off-by: Ben Widawsky --- drivers/cxl/core/bus.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/drivers/cxl/core/bus.c b/drivers/cxl/core/bus.c index 3991ac231c3e..9d98dd50d424 100644 --- a/drivers/cxl/core/bus.c +++ b/drivers/cxl/core/bus.c @@ -453,6 +453,19 @@ int cxl_add_dport(struct cxl_port *port, struct device *dport_dev, int port_id, } EXPORT_SYMBOL_GPL(cxl_add_dport); +/** + * cxl_decoder_alloc - Allocate a new CXL decoder + * @port: owning port of this decoder + * @nr_targets: downstream targets accessible by this decoder + * + * A port should contain one or more decoders. Each of those decoders enable + * some address space for CXL.mem utilization. Therefore, it is logical to + * allocate decoders while enumerating a port. While >= 1 is defined by the CXL + * specification, due to error conditions it is possible that a port may have 0 + * decoders. + * + * Return: A new cxl decoder which wants to be added with cxl_decoder_add() + */ struct cxl_decoder *cxl_decoder_alloc(struct cxl_port *port, int nr_targets) { struct cxl_decoder *cxld; @@ -491,6 +504,21 @@ struct cxl_decoder *cxl_decoder_alloc(struct cxl_port *port, int nr_targets) } EXPORT_SYMBOL_GPL(cxl_decoder_alloc); +/** + * cxl_decoder_add - Add a decoder with targets + * @host: The containing struct device. This is typically the PCI device that is + * CXL capable + * @cxld: The cxl decoder allocated by cxl_decoder_alloc() + * @target_map: A list of downstream ports that this decoder can direct memory + * traffic to. These numbers should correspond with the port number + * in the PCIe Link Capabilities structure. + * + * Return: 0 if decoder was successfully added. + * + * Certain types of decoders may not have any targets. The main example of this + * is an endpoint device. A more awkward example is a hostbridge whose root + * ports get hot added (technically possible, though unlikely). + */ int cxl_decoder_add(struct device *host, struct cxl_decoder *cxld, int *target_map) {