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 EA357C6FD18 for ; Wed, 29 Mar 2023 09:48:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231172AbjC2Jse (ORCPT ); Wed, 29 Mar 2023 05:48:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48494 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231166AbjC2Jsc (ORCPT ); Wed, 29 Mar 2023 05:48:32 -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 095191990; Wed, 29 Mar 2023 02:48:31 -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=au9j1RKX6uBNeqzDDu1OuVZGAvYR+PBKjc7fF9etf8g=; b=uQR1dij+ectpu7hzYEJ45EbjLP sQ/NxyhnOmjLTKzzlicb6edwu3KbL2D9pfnGksaT1qEvWY28vo3bmL+uWaB3oSQwJBHho1RPlZ4ZH Yw8gA5FGztN+Szwpc3fs00oAbQIliZ3Fbv7UOaoGaC3gtDXLlZn8VVEPw/bCiIxeBLoWGkWRYPRQm He4yJWhNFMe+Y8c3Gc9d4L5Cebsh0LzVydvvdbW3NeKnckV7xbaXPbHFyoDRBR8+/d1n/4YEKgyBq vHrBAElZLL1vlGjGB3R9dcOLxSE0iVbDHcos/7joOAQS0mcNtMSpCzh7Lq0i6nfx9MJF2UtzEcM6l NH2HaebA==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:41268) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1phSPd-0008J7-UH; Wed, 29 Mar 2023 10:48:13 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1phSPZ-0007Pv-Qo; Wed, 29 Mar 2023 10:48:09 +0100 Date: Wed, 29 Mar 2023 10:48:09 +0100 From: "Russell King (Oracle)" To: "Sit, Michael Wei Hong" Cc: Jakub Kicinski , Giuseppe Cavallaro , Alexandre Torgue , Jose Abreu , "David S . Miller" , Eric Dumazet , Paolo Abeni , Maxime Coquelin , "Ong, Boon Leong" , "netdev@vger.kernel.org" , "linux-stm32@st-md-mailman.stormreply.com" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "Looi, Hong Aun" , "Voon, Weifeng" , "Lai, Peter Jun Ann" Subject: Re: [PATCH net v3 1/3] net: phylink: add phylink_expects_phy() method Message-ID: References: <20230324081656.2969663-1-michael.wei.hong.sit@intel.com> <20230324081656.2969663-2-michael.wei.hong.sit@intel.com> <20230328185720.6239e4a7@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: Russell King (Oracle) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, Mar 29, 2023 at 09:34:05AM +0000, Sit, Michael Wei Hong wrote: > > > > -----Original Message----- > > From: Russell King > > Sent: Wednesday, March 29, 2023 5:01 PM > > To: Jakub Kicinski > > Cc: Sit, Michael Wei Hong ; > > Giuseppe Cavallaro ; Alexandre Torgue > > ; Jose Abreu > > ; David S . Miller ; > > Eric Dumazet ; Paolo Abeni > > ; Maxime Coquelin > > ; Ong, Boon Leong > > ; netdev@vger.kernel.org; linux- > > stm32@st-md-mailman.stormreply.com; linux-arm- > > kernel@lists.infradead.org; linux-kernel@vger.kernel.org; Looi, > > Hong Aun ; Voon, Weifeng > > ; Lai, Peter Jun Ann > > > > Subject: Re: [PATCH net v3 1/3] net: phylink: add > > phylink_expects_phy() method > > > > On Tue, Mar 28, 2023 at 06:57:20PM -0700, Jakub Kicinski wrote: > > > On Fri, 24 Mar 2023 16:16:54 +0800 Michael Sit Wei Hong wrote: > > > > Provide phylink_expects_phy() to allow MAC drivers to check if it > > is > > > > expecting a PHY to attach to. Since fixed-linked setups do not > > need > > > > to attach to a PHY. > > > > > > > > Provides a boolean value as to if the MAC should expect a PHY. > > > > returns true if a PHY is expected. > > > > > > > > Signed-off-by: Michael Sit Wei Hong > > > > > > > > Russell, looks good? > > > > Not really, given that phylink_attach_phy() will refuse to attach a > > PHY > > when: > > > > if (WARN_ON(pl->cfg_link_an_mode == MLO_AN_FIXED || > > (pl->cfg_link_an_mode == MLO_AN_INBAND && > > phy_interface_mode_is_8023z(interface) && !pl- > > >sfp_bus))) > > return -EINVAL; > > > > So, if we introduce a helper named "phylink_expects_phy" that > > returns true when cfg_link_an_mode == MLO_AN_INBAND and the > > interface mode is e.g. 1000base-X, but then someone tries to attach > > a PHY, the kernel spits out a warning, backtrace, and a return value > > of -EINVAL, things are going to look really rather stupid. > > > Should we check for these 3 conditions as well then? > (pl->cfg_link_an_mode == MLO_AN_INBAND && > phy_interface_mode_is_8023z(interface) && !pl->sfp_bus) > to determine if phylink expects a phy. If there's a sfp bus, then we don't expect a PHY from the MAC driver (as there can only be one PHY attached), and as phylink_expects_phy() is for the MAC driver to use, we should be returning false if pl->sfp_bus != NULL. pl->cfg_link_an_mode == MLO_AN_FIXED || (pl->cfg_link_an_mode == MLO_AN_INBAND && phy_interface_mode_is_8023z(interface)) Is true when we're in fixed-link mode, or if we're in in-band mode and using 1000base-X or 25000base-X. These are the conditions that we don't expect the MAC driver to give us a PHY. To put that in positive logic, we expect a PHY from the MAC when we're in PHY mode, or when we're in in-band mode and using SGMII, QSGMII, USXGMII, RGMII, etc. The reason for the extra "&& !pl->sfp_bus" in phylink_attach_phy() is to allow SFPs to connect to the MAC using inband mode with 1000base-X and 2500base-X interface modes. These are not for the MAC-side of things though. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!