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=-7.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,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 851A1C433E0 for ; Tue, 16 Feb 2021 10:26:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 391C064DA8 for ; Tue, 16 Feb 2021 10:26:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230097AbhBPKZu (ORCPT ); Tue, 16 Feb 2021 05:25:50 -0500 Received: from fllv0015.ext.ti.com ([198.47.19.141]:52852 "EHLO fllv0015.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229923AbhBPKZl (ORCPT ); Tue, 16 Feb 2021 05:25:41 -0500 Received: from fllv0034.itg.ti.com ([10.64.40.246]) by fllv0015.ext.ti.com (8.15.2/8.15.2) with ESMTP id 11GAOeRs127257; Tue, 16 Feb 2021 04:24:40 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1613471080; bh=jXP/A7m1+bRyusmpL52wb3C/gRf4Bo6Hw3U3UA3/J00=; h=Subject:To:CC:References:From:Date:In-Reply-To; b=GedDc0/SqmIZkDbq5PAfBWDTHHn4XOOKFbSDL9C+GnB+tFeuMKrjlaYUapRHsiZiQ hYzFmU6ZeNuEBK3OjHPJ0Hjxz68Im473WdNpa7PKmX289A6NnLKtMcI6b3u7wA4aXy CH52r8WUMom0okKamv0eH+FZAvzGKF+34GfLecAY= Received: from DLEE105.ent.ti.com (dlee105.ent.ti.com [157.170.170.35]) by fllv0034.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 11GAOeDY090324 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Tue, 16 Feb 2021 04:24:40 -0600 Received: from DLEE111.ent.ti.com (157.170.170.22) by DLEE105.ent.ti.com (157.170.170.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1979.3; Tue, 16 Feb 2021 04:24:40 -0600 Received: from lelv0326.itg.ti.com (10.180.67.84) by DLEE111.ent.ti.com (157.170.170.22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1979.3 via Frontend Transport; Tue, 16 Feb 2021 04:24:40 -0600 Received: from [10.250.234.229] (ileax41-snat.itg.ti.com [10.172.224.153]) by lelv0326.itg.ti.com (8.15.2/8.15.2) with ESMTP id 11GAOZ58004811; Tue, 16 Feb 2021 04:24:36 -0600 Subject: Re: [PATCH v14 2/4] phy: Add media type and speed serdes configuration interfaces To: Steen Hegelund , Andrew Lunn CC: Vinod Koul , Alexandre Belloni , Lars Povlsen , Bjarni Jonasson , Microchip UNG Driver List , , References: <20210210085255.2006824-1-steen.hegelund@microchip.com> <20210210085255.2006824-3-steen.hegelund@microchip.com> <04d91f6b-775a-8389-b813-31f7b4a778cb@ti.com> <704b850f-9345-2e36-e84b-b332fed22270@ti.com> From: Kishon Vijay Abraham I Message-ID: Date: Tue, 16 Feb 2021 15:54:35 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 8bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 16/02/21 2:07 pm, Steen Hegelund wrote: > Hi Andrew and Kishon, > > On Mon, 2021-02-15 at 15:07 +0100, Andrew Lunn wrote: >> EXTERNAL EMAIL: Do not click links or open attachments unless you >> know the content is safe >> >> On Mon, Feb 15, 2021 at 05:25:10PM +0530, Kishon Vijay Abraham I >> wrote: >>> Okay. Is it going to be some sort of manual negotiation where the >>> Ethernet controller invokes set_speed with different speeds? Or the >>> Ethernet controller will get the speed using some out of band >>> mechanism >>> and invokes set_speed once with the actual speed? >> >> Hi Kishon >> >> There are a few different mechanism possible. >> >> The SFP has an EEPROM which contains lots of parameters. One is the >> maximum baud rate the module supports. PHYLINK will combine this >> information with the MAC capabilities to determine the default speed. >> >> The users can select the mode the MAC works in, e.g. 1000BaseX vs >> 2500BaseX, via ethtool -s. Different modes needs different speeds. >> >> Some copper PHYs will change there host side interface baud rate when >> the media side interface changes mode. 10GBASE-X for 10G copper, >> 5GBase-X for 5G COPPER, 2500Base-X for 2.5G copper, and SGMII for >> old school 10/100/1G Ethernet. >> >> Mainline Linux has no support for it, but some 'vendor crap' will do >> a >> manual negotiation, simply trying different speeds and see if the >> SERDES establishes link. There is nothing standardised for this, as >> far as i know. >> >>     Andrew > > Yes, in case I mention the only way to ensure communication is human > intervention to set the speed to the highest common denominator. Okay.. is it the same case for set_media as well? Thanks Kishon