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=-5.0 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 ECC9DC6379C for ; Tue, 20 Jul 2021 14:41:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D58C9610A0 for ; Tue, 20 Jul 2021 14:41:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240186AbhGTOAX (ORCPT ); Tue, 20 Jul 2021 10:00:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42814 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240178AbhGTNvp (ORCPT ); Tue, 20 Jul 2021 09:51:45 -0400 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E0951C0613DE for ; Tue, 20 Jul 2021 07:30:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=OTUTsE3kw2/hXyNWz/pqNqxeAFfdkNNb0CODpx/Iecs=; b=mzHNWH875zR6UjvGtXe0aFdF6 py5tO6rfIh3AtR/G5wOcn3xE+mFrpFCc1MB+MHRuczpWIRA7+/7SRl2Dfo5VTB0WfPjJAO7Q6y/rI MzZecNySlm+n4QGkOL9CA3Fo26//GrIz8HQFqi2ecICLjhGtwoULiPSxH3s4QetFigbbWJjvZCj46 JDknAkfWNRLUE0qpbEJKVITaSVmVSk89YBaTcRIsMpyEzvZa6lGnJuN46AqmdqbX5ypzcmEvN/htb 4qu3LlxaqMYHYEkG0OOShst8/HY2uTcmPODAz8ZYgamie9LCMh25NWOVatqb0sNpwa1UHMk6W8bId N5c5KVVgg==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:46374) by pandora.armlinux.org.uk with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1m5qli-0006VO-R5; Tue, 20 Jul 2021 15:30:46 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1m5qli-0006z1-D6; Tue, 20 Jul 2021 15:30:46 +0100 Date: Tue, 20 Jul 2021 15:30:46 +0100 From: "Russell King (Oracle)" To: Andrew Lunn Cc: Heiner Kallweit , "David S. Miller" , netdev@vger.kernel.org, Marek Beh__n , Jakub Kicinski Subject: Re: [PATCH RFC net-next] net: phy: marvell10g: add downshift tunable support Message-ID: <20210720143046.GU22278@shell.armlinux.org.uk> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: Russell King (Oracle) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, Jul 20, 2021 at 04:28:12PM +0200, Andrew Lunn wrote: > > +static int mv3310_set_downshift(struct phy_device *phydev, u8 ds) > > +{ > > + struct mv3310_priv *priv = dev_get_drvdata(&phydev->mdio.dev); > > + u16 val; > > + int err; > > + > > + /* Fails to downshift with v0.3.5.0 and earlier */ > > + if (priv->firmware_ver < MV_VERSION(0,3,5,0)) > > + return -EOPNOTSUPP; > > + > > + if (ds == DOWNSHIFT_DEV_DISABLE) > > + return phy_clear_bits_mmd(phydev, MDIO_MMD_PCS, MV_PCS_DSC1, > > + MV_PCS_DSC1_ENABLE); > > + > > + /* FIXME: The default is disabled, so should we disable? */ > > + if (ds == DOWNSHIFT_DEV_DEFAULT_COUNT) > > + ds = 2; > > Interesting question. > > It is a useful feature, so i would enable it by default. > > Is it possible to read the actual speed via some vendor register? The > phy-core might then give a warning, but it is 50/50 since the link > peer might perform the downshift. We already do read the actual negotiated speed anbd other parameters from the MV_PCS_CSSR1 register. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!