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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7F979EB64DD for ; Fri, 23 Jun 2023 13:32:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229666AbjFWNcf (ORCPT ); Fri, 23 Jun 2023 09:32:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54750 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229657AbjFWNcb (ORCPT ); Fri, 23 Jun 2023 09:32:31 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A45B52130; Fri, 23 Jun 2023 06:32:30 -0700 (PDT) Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4QndRp0hpJz6J66G; Fri, 23 Jun 2023 21:31:18 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.27; Fri, 23 Jun 2023 14:32:28 +0100 Date: Fri, 23 Jun 2023 14:32:27 +0100 From: Jonathan Cameron To: Terry Bowman CC: , , , , , , , , , Subject: Re: [PATCH v7 14/27] cxl/port: Store the port's Component Register mappings in struct cxl_port Message-ID: <20230623143227.00001bf6@Huawei.com> In-Reply-To: <20230622205523.85375-15-terry.bowman@amd.com> References: <20230622205523.85375-1-terry.bowman@amd.com> <20230622205523.85375-15-terry.bowman@amd.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.227.76] X-ClientProxiedBy: lhrpeml500001.china.huawei.com (7.191.163.213) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 22 Jun 2023 15:55:10 -0500 Terry Bowman wrote: > From: Robert Richter > > CXL capabilities are stored in the Component Registers. To use them, > the specific I/O ranges of the capabilities must be determined by > probing the registers. For this, the whole Component Register range > needs to be mapped temporarily to detect the offset and length of a > capability range. > > In order to use more than one capability of a component (e.g. RAS and > HDM) the Component Register are probed and its mappings created > multiple times. This also causes overlapping I/O ranges as the whole > Component Register range must be mapped again while a capability's I/O > range is already mapped. > > Different capabilities cannot be setup at the same time. E.g. the RAS > capability must be made available as soon as the PCI driver is bound, > the HDM decoder is setup later during port enumeration. Moreover, > during early setup it is still unknown if a certain capability is > needed. A central capability setup is therefore not possible, > capabilities must be individually enabled once needed during > initialization. > > To avoid a duplicate register probe and overlapping I/O mappings, only > probe the Component Registers one time and store the Component > Register mapping in struct port. The stored mappings can be used later > to iomap the capability register range when enabling the capability, > which will be implemented in a follow-on patch. > > Signed-off-by: Robert Richter > Signed-off-by: Terry Bowman Reviewed-by: Jonathan Cameron