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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 49104C433DB for ; Fri, 8 Jan 2021 02:10:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EA15A23603 for ; Fri, 8 Jan 2021 02:10:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728605AbhAHCK5 (ORCPT ); Thu, 7 Jan 2021 21:10:57 -0500 Received: from mga07.intel.com ([134.134.136.100]:14295 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726720AbhAHCK4 (ORCPT ); Thu, 7 Jan 2021 21:10:56 -0500 IronPort-SDR: UgUgcL2Do8tlDxWhsfeSSK3y120PeIPw1txt72cj29FNaRrJ2niXqGpYkMMtYCaXkluDNFjt4v Az4X2UsdMPPw== X-IronPort-AV: E=McAfee;i="6000,8403,9857"; a="241601783" X-IronPort-AV: E=Sophos;i="5.79,330,1602572400"; d="scan'208";a="241601783" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jan 2021 18:10:15 -0800 IronPort-SDR: N67v0aA70R1CbVpDWG5IJqyPmHZjZE5QRETh5lKYQSZmJ7UoltFbrPBaMZfCXgGJ+PAUuksAYf oC/nYXt/PvLg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.79,330,1602572400"; d="scan'208";a="398826424" Received: from yilunxu-optiplex-7050.sh.intel.com (HELO localhost) ([10.239.159.141]) by fmsmga002.fm.intel.com with ESMTP; 07 Jan 2021 18:10:12 -0800 Date: Fri, 8 Jan 2021 10:05:26 +0800 From: Xu Yilun To: Greg KH Cc: andrew@lunn.ch, arnd@arndb.de, lee.jones@linaro.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, trix@redhat.com, lgoncalv@redhat.com, hao.wu@intel.com, matthew.gerlach@intel.com, russell.h.weight@intel.com, yilun.xu@intel.com Subject: Re: [RESEND PATCH 2/2] misc: add support for retimers interfaces on Intel MAX 10 BMC Message-ID: <20210108020526.GB13860@yilunxu-OptiPlex-7050> References: <1609999628-12748-1-git-send-email-yilun.xu@intel.com> <1609999628-12748-3-git-send-email-yilun.xu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 07, 2021 at 10:26:12AM +0100, Greg KH wrote: > On Thu, Jan 07, 2021 at 02:07:08PM +0800, Xu Yilun wrote: > > This driver supports the ethernet retimers (C827) for the Intel PAC > > (Programmable Acceleration Card) N3000, which is a FPGA based Smart NIC. > > > > C827 is an Intel(R) Ethernet serdes transceiver chip that supports > > up to 100G transfer. On Intel PAC N3000 there are 2 C827 chips > > managed by the Intel MAX 10 BMC firmware. They are configured in 4 ports > > 10G/25G retimer mode. Host could query their link states and firmware > > version information via retimer interfaces (Shared registers) on Intel > > MAX 10 BMC. The driver creates sysfs interfaces for users to query these > > information. > > Networking people, please look at this sysfs file: > > > +What: /sys/bus/platform/devices/n3000bmc-retimer.*.auto/link_statusX > > +Date: Jan 2021 > > +KernelVersion: 5.12 > > +Contact: Xu Yilun > > +Description: Read only. Returns the status of each line side link. "1" for > > + link up, "0" for link down. > > + Format: "%u". > > as I need your approval to add it because it is not the "normal" way for > link status to be exported to userspace. > > One code issue: > > > +#define to_link_attr(dev_attr) \ > > + container_of(dev_attr, struct link_attr, attr) > > + > > +static ssize_t > > +link_status_show(struct device *dev, struct device_attribute *attr, char *buf) > > +{ > > + struct m10bmc_retimer *retimer = dev_get_drvdata(dev); > > + struct link_attr *lattr = to_link_attr(attr); > > + unsigned int val; > > + int ret; > > + > > + ret = m10bmc_sys_read(retimer->m10bmc, M10BMC_PKVL_LSTATUS, &val); > > + if (ret) > > + return ret; > > + > > + return sysfs_emit(buf, "%u\n", > > + !!(val & BIT((retimer->id << 2) + lattr->index))); > > +} > > + > > +#define link_status_attr(_index) \ > > + static struct link_attr link_attr_status##_index = \ > > + { .attr = __ATTR(link_status##_index, 0444, \ > > + link_status_show, NULL), \ > > + .index = (_index) } > > Why is this a "raw" attribute and not a device attribute? It is actually a device_attribute. The device_attribute is embedded in link_attr, like: struct link_attr { struct device_attribute attr; u32 index; }; An index for the link is appended along with the device_attribute, so we could identify which link is being queried on link_status_show(). There are 4 links and this is to avoid duplicated code like link_status_1_show(), link_status_2_show() ... > > Please just use a normal DEVICE_ATTR_RO() macro to make it simpler and DEVICE_ATTR_RO() is to define a standalone device_attribute variable, but here we are initializing a field in struct link_attr. Thanks, Yilun > easier to understand over time, what you are doing here. I can't > determine what is happening with this code now... > > thanks, > > greg k-h