From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [78.32.30.218]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 92662179BC; Mon, 17 Feb 2025 14:21:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=78.32.30.218 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739802101; cv=none; b=XHXIjvNn2C7fWz5ekN2E9bJEsrxLSPAqM6/z+HoxgiJL9beHhd/sZ54C2/KVX5VKLKd5EBsx3OA1AbKRWqCpeEzRTEI8MiZC1cSLY/7HQ2Jw764C/i8qcUdL0y57bAA9RtQ7bkobz1Cydpdhq8NcWts7WqujTwgXYvB5PrpAVnQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739802101; c=relaxed/simple; bh=BJglNCLgDoRehZkHvYuLehjrYWHHpDkp1i8i+gd9c34=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=JbuUQ/QUxYSDXBAVxS8oLqppsgMAzzKX9dTuvYaMZ0Mg1e+S/7NaOAcddXHf5pH812brmKGjj0BoD20BQ5i3W28VOfCKV2baBHZro5IOfJZMpCy2ynGxbt6d8Y3S7kFuz6VeJ1ywfW70LzOgYJCRpVpvcm4sfxkzojevxh5tfZ0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk; spf=none smtp.mailfrom=armlinux.org.uk; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b=TNNthJYg; arc=none smtp.client-ip=78.32.30.218 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="TNNthJYg" 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=2m1Fn2cs47esDRZLqZGoIEgYTLep9xsmVfAdq3qlyCs=; b=TNNthJYgcXpz/nfrJyCILETGwQ rwYd+O4HWS9Wz2Hx0R2/UB7Zc5pp7aFjK0L0RIKIQPZvFGURXiAiCrPE4443CBWM0ghjrYNdXlBW7 ula/FZXItczt+kvnzMLFpG+pyZFKLt4LLlydYktUYCTacN41yN/uy5ubtFk2R3/TUo+l94TY2Wx89 oQs2teE7o/Dth/kCDTq5EGlww4MzUT5xuVsh2/L8gZjaER0FPr6vJQcSHL8MlxfpBSNT/qwv6sotg jHFFSFAwR/TkqbX4rP9f7m+bOdrAiRvcwmx2ueqM83+BbHWknD+lmSSPuxB+h3xCoKHRT5Fsa8ivB ozJ2Xulg==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:42956) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1tk205-0006sW-2T; Mon, 17 Feb 2025 14:21:34 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.96) (envelope-from ) id 1tk201-0006Hd-1e; Mon, 17 Feb 2025 14:21:29 +0000 Date: Mon, 17 Feb 2025 14:21:29 +0000 From: "Russell King (Oracle)" To: Maxime Chevallier Cc: davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, thomas.petazzoni@bootlin.com, Andrew Lunn , Jakub Kicinski , Eric Dumazet , Paolo Abeni , linux-arm-kernel@lists.infradead.org, Christophe Leroy , Herve Codina , Florian Fainelli , Heiner Kallweit , Vladimir Oltean , =?iso-8859-1?Q?K=F6ry?= Maincent , Marek =?iso-8859-1?Q?Beh=FAn?= , Oleksij Rempel , =?iso-8859-1?Q?Nicol=F2?= Veronese , Simon Horman , mwojtas@chromium.org, Antoine Tenart , devicetree@vger.kernel.org, Conor Dooley , Krzysztof Kozlowski , Rob Herring , Romain Gantois , Daniel Golle , Dimitri Fedrau , Sean Anderson Subject: Re: [PATCH net-next v4 05/15] net: phy: Create a phy_port for PHY-driven SFPs Message-ID: References: <20250213101606.1154014-1-maxime.chevallier@bootlin.com> <20250213101606.1154014-6-maxime.chevallier@bootlin.com> <20250217092911.772da5d0@fedora.home> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250217092911.772da5d0@fedora.home> Sender: Russell King (Oracle) On Mon, Feb 17, 2025 at 09:29:11AM +0100, Maxime Chevallier wrote: > Hello Russell, > > On Sat, 15 Feb 2025 18:57:01 +0000 > "Russell King (Oracle)" wrote: > > > On Thu, Feb 13, 2025 at 11:15:53AM +0100, Maxime Chevallier wrote: > > > Some PHY devices may be used as media-converters to drive SFP ports (for > > > example, to allow using SFP when the SoC can only output RGMII). This is > > > already supported to some extend by allowing PHY drivers to registers > > > themselves as being SFP upstream. > > > > > > However, the logic to drive the SFP can actually be split to a per-port > > > control logic, allowing support for multi-port PHYs, or PHYs that can > > > either drive SFPs or Copper. > > > > > > To that extent, create a phy_port when registering an SFP bus onto a > > > PHY. This port is considered a "serdes" port, in that it can feed data > > > to anther entity on the link. The PHY driver needs to specify the > > > various PHY_INTERFACE_MODE_XXX that this port supports. > > > > > > Signed-off-by: Maxime Chevallier > > > > With this change, using phy_port requires phylink to also be built in > > an appropriate manner. Currently, phylink depends on phylib. phy_port > > becomes part of phylib. This patch makes phylib depend on phylink, > > thereby creating a circular dependency when modular. > > > > I think a different approach is needed here. > > That's true. > > One way to avoid that would be to extract out of phylink/phylib all the > functions for linkmode handling that aren't tied to phylink/phylib > directly, but are about managing the capabilities of each interface, > linkmode, speed, duplex, etc. For phylink, that would be : > > phylink_merge_link_mode > phylink_get_capabilities > phylink_cap_from_speed_duplex > phylink_limit_mac_speed > phylink_caps_to_linkmodes > phylink_interface_max_speed > phylink_interface_signal_rate > phylink_is_empty_linkmode > phylink_an_mode_str > phylink_set_port_modes > > For now all these are phylink internal and that makes sense, but if we want > phy-driven SFP support, stackable PHYs and so on, we'll need some ways for > the PHY to expose its media-side capabilities, and we'd reuse these. > > These would go into linkmode.c/h for example, and we'd have a shared set > of helpers that we can use in phylink, phylib and phy_port. > > Before I go around and rearrange that, are you OK with this approach ? I'm not convinced. If you're thinking of that level of re-use, you're probably going to miss out on a lot of logic that's in phylink. Maybe there should be a way to re-use phylink in its entirety between the PHY and SFP. Some of the above (that deal only with linkmodes) would make sense to move out though. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!