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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_MUTT autolearn=unavailable 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 B5FC2C48BE4 for ; Thu, 27 Jun 2019 19:28:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 97FDF208E3 for ; Thu, 27 Jun 2019 19:28:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=lunn.ch header.i=@lunn.ch header.b="KXsLMH0h" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726480AbfF0T2h (ORCPT ); Thu, 27 Jun 2019 15:28:37 -0400 Received: from vps0.lunn.ch ([185.16.172.187]:38366 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726384AbfF0T2h (ORCPT ); Thu, 27 Jun 2019 15:28:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Transfer-Encoding:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: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=pfFOMoKJzOKIQebJNqxQnidmbuTVklA+Iu6cpCenVNE=; b=KXsLMH0hNE8NJ4cEwwQM99d3Me gRSSxDznM4Bg2y37GuZ5KL6eCrBoR2YCPrkvTLWL2r2BtqaeoioZPnXheGxF8DoLf3svxxhEwDuMJ sSCtzMcfYZO3ZVB6LfQlde6hYtvefr76UEEHBaqjXCMjOQOuFyhU5uxartSW9ErTnewE=; Received: from andrew by vps0.lunn.ch with local (Exim 4.89) (envelope-from ) id 1hga3y-00037F-Tj; Thu, 27 Jun 2019 21:28:06 +0200 Date: Thu, 27 Jun 2019 21:28:06 +0200 From: Andrew Lunn To: Daniel Santos Cc: Russell King - ARM Linux admin , =?iso-8859-1?Q?Ren=E9?= van Dorst , sean.wang@mediatek.com, f.fainelli@gmail.com, davem@davemloft.net, matthias.bgg@gmail.com, vivien.didelot@gmail.com, frank-w@public-files.de, netdev@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-mips@vger.kernel.org Subject: Re: [PATCH RFC net-next 1/5] net: dsa: mt7530: Convert to PHYLINK API Message-ID: <20190627192806.GQ27733@lunn.ch> References: <20190624145251.4849-1-opensource@vdorst.com> <20190624145251.4849-2-opensource@vdorst.com> <20190624153950.hdsuhrvfd77heyor@shell.armlinux.org.uk> <20190625113158.Horde.pCaJOVUsgyhYLd5Diz5EZKI@www.vdorst.com> <20190625121030.m5w7wi3rpezhfgyo@shell.armlinux.org.uk> <1ad9f9a5-8f39-40bd-94bb-6b700f30c4ba@pobox.com> <20190625190246.GA27733@lunn.ch> <4fc51dc4-0eec-30d7-86d1-3404819cf6fe@pobox.com> <20190625204148.GB27733@lunn.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org > > Looking at the data sheet page, you want FORCE_MODE_Pn set. You never > > want the MAC directly talking to the PHY. Bad things will happen. > > So what exactly do you mean by the MAC directly talking to the PHY?  Do > you mean setting speed, duplex, etc. via the MAC registers instead of > via MDIO to the MII registers of the PHY? The data sheet implies the MAC hardware performs reads on the PHY to get the status, and then uses that to configure the MAC. This is often called PHY polling. The MAC hardware however has no idea what the PHY driver is doing. The MAC does not take the PHY mutex. So the PHY driver might be doing something at the same time the MAC hardware polls the PHY, and it gets odd results. Some PHYs have multiple pages, and for example reading the temperature sensor means swapping pages. If the MAC hardware was to poll while the sensor is being read, it would not get the link status, it would read some random temperature register. So you want the PHY driver to read the results of auto-neg and it then tell the MAC the results, so the MAC can be configured correctly. > > Then use FORCE_RX_FC_Pn and FORCE_TX_Pn to reflect phydev->pause and > > phydev->asym_pause. > > > > The same idea applies when using phylink. > > > > Andrew > > You're help is greatly appreciated here.  Admittedly, I'm also trying to > get this working in the now deprecated swconfig for a 3.18 kernel that's > in production. I'm not very familiar with swconfig. Is there software driving the PHY? If not, it is then safe for the MAC hardware to poll the PHY. Andrew