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 E50F2C71153 for ; Tue, 29 Aug 2023 13:59:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236555AbjH2N6s (ORCPT ); Tue, 29 Aug 2023 09:58:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39746 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236627AbjH2N6c (ORCPT ); Tue, 29 Aug 2023 09:58:32 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A4864E0; Tue, 29 Aug 2023 06:58:29 -0700 (PDT) Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4RZpL74jLhz6K6Fx; Tue, 29 Aug 2023 21:34:07 +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 15.1.2507.31; Tue, 29 Aug 2023 14:38:52 +0100 Date: Tue, 29 Aug 2023 14:38:51 +0100 From: Jonathan Cameron To: Terry Bowman CC: , , , , , , , , , Subject: Re: [PATCH v9 01/15] cxl/port: Pre-initialize component register mappings Message-ID: <20230829143851.00006467@Huawei.com> In-Reply-To: <20230825233211.3029825-2-terry.bowman@amd.com> References: <20230825233211.3029825-1-terry.bowman@amd.com> <20230825233211.3029825-2-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: lhrpeml500006.china.huawei.com (7.191.161.198) 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 Fri, 25 Aug 2023 18:31:57 -0500 Terry Bowman wrote: > From: Robert Richter Hi Robert, Terry, > > The component registers of a component may not exist or are not > needed. How do we now it's not needed in this function? Perhaps "may not exist." is the bit that matters in this sentence. > The setup may fail for that reason. In some cases the > initialization should continue anyway. Thus, always initialize struct > cxl_register_map with valid values. In case of errors, zero it, set a > value for @dev and make @resource a the valid value using make @resource CXL_RESOURCE_NONE. (not "a the") > CXL_RESOURCE_NONE. It might be worth making it clear that this will (I think) only matter for future usecases and isn't a fix for how this function is used today. > > Signed-off-by: Robert Richter > Signed-off-by: Terry Bowman Otherwise seems sensible to me with one comment below. Reviewed-by: Jonathan Cameron > --- > drivers/cxl/core/port.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c > index 724be8448eb4..2d22e7a5629b 100644 > --- a/drivers/cxl/core/port.c > +++ b/drivers/cxl/core/port.c > @@ -693,16 +693,17 @@ static struct cxl_port *cxl_port_alloc(struct device *uport_dev, > static int cxl_setup_comp_regs(struct device *dev, struct cxl_register_map *map, > resource_size_t component_reg_phys) > { > - if (component_reg_phys == CXL_RESOURCE_NONE) > - return 0; > - > *map = (struct cxl_register_map) { > .dev = dev, > - .reg_type = CXL_REGLOC_RBI_COMPONENT, Could set this explicitly to CXL_REGLOC_RBI_EMPTY which is what happens anyway, but it isn't obvious that 0 maps to something that indicates this doesn't exist. > .resource = component_reg_phys, > - .max_size = CXL_COMPONENT_REG_BLOCK_SIZE, > }; > > + if (component_reg_phys == CXL_RESOURCE_NONE) > + return 0; > + > + map->reg_type = CXL_REGLOC_RBI_COMPONENT; > + map->max_size = CXL_COMPONENT_REG_BLOCK_SIZE; > + > return cxl_setup_regs(map); > } >