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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 52CAAC83F1B for ; Thu, 17 Jul 2025 08:33:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=4jTDyoISAKqJ6yoBRmBxJGabYsMp9DWXVs7dHeIYUcU=; b=mKovyZPDgwUhU2U6Kf1I3XCm8B ecBmd6iOSnLWtjek6VIFB2pGvDbJ5rwoPf3qSE/Z/RJbBJjp02nNPE/rjyv+UGXtOmLu6SBkvChUh P4cERbKjD8fBLkQ6NW49H6tlEUJw/yCj40ukJHDs8Jmrod0AMXxXnrMC3gi1PmiBflOCMRYKD47r0 1l5gVdXUpR/v4ahgHR1Pn0u6hMLSbZQoeBXUF1TUqpLmHiEZbYg8EtVau4X8VqQ+dDp9pjRX/V2cT XicAsd11mcf8NO2XneVp48deXD0ORlxMHVpxAxL82HkIwKkOkB6iXACcbJwGI8EVyE1kKcMeOeOut vL7IDr7w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1ucK3P-00000009a1u-2iNN; Thu, 17 Jul 2025 08:33:23 +0000 Received: from relay9-d.mail.gandi.net ([217.70.183.199]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1ucJ4r-00000009S95-2bf4 for linux-arm-kernel@lists.infradead.org; Thu, 17 Jul 2025 07:30:50 +0000 Received: by mail.gandi.net (Postfix) with ESMTPSA id D10D9443E8; Thu, 17 Jul 2025 07:30:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1752737448; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=4jTDyoISAKqJ6yoBRmBxJGabYsMp9DWXVs7dHeIYUcU=; b=Y8U1vxSqPs0StEXualMiHptg9f+IeS2axb8oxhi7bMllkCU9xYeY52GFLRt1C7Lw2Ft7bN rXCT09IMTzTSmChU9BZJj9mgwjSxXYu/GwSud6o5T0Y94lOTYvlFm8063m1cKGHbSkRiHA y54QAV1ixQX2rlClfhWPdrwEs0fydomDWgZqj3aGg/RwSAgSoxvcgPdhyGKxuGAv7DCeFz g4vD52nV0Rnw25zfg+xxnUwU24IlClMYnTHueJ2y0lsEqEH7jWVNMNV4kVb7W/EiVlKZeP nV7S2rFrUmepl3v6qmyTqcB/pgHLnms1MBIi1ouP3nnanwKlsgCVWtclqJQbbA== From: Maxime Chevallier To: davem@davemloft.net Cc: Maxime Chevallier , 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 , Russell King , linux-arm-kernel@lists.infradead.org, Christophe Leroy , Herve Codina , Florian Fainelli , Heiner Kallweit , Vladimir Oltean , =?UTF-8?q?K=C3=B6ry=20Maincent?= , =?UTF-8?q?Marek=20Beh=C3=BAn?= , Oleksij Rempel , =?UTF-8?q?Nicol=C3=B2=20Veronese?= , Simon Horman , mwojtas@chromium.org, Antoine Tenart , devicetree@vger.kernel.org, Conor Dooley , Krzysztof Kozlowski , Rob Herring , Romain Gantois , Daniel Golle , Dimitri Fedrau Subject: [PATCH net-next v9 15/15] Documentation: networking: Document the phy_port infrastructure Date: Thu, 17 Jul 2025 09:30:19 +0200 Message-ID: <20250717073020.154010-16-maxime.chevallier@bootlin.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250717073020.154010-1-maxime.chevallier@bootlin.com> References: <20250717073020.154010-1-maxime.chevallier@bootlin.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-GND-State: clean X-GND-Score: -100 X-GND-Cause: gggruggvucftvghtrhhoucdtuddrgeeffedrtdefgdehleellecutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfitefpfffkpdcuggftfghnshhusghstghrihgsvgenuceurghilhhouhhtmecufedtudenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhephffvvefufffkofgjfhgggfestdekredtredttdenucfhrhhomhepofgrgihimhgvucevhhgvvhgrlhhlihgvrhcuoehmrgigihhmvgdrtghhvghvrghllhhivghrsegsohhothhlihhnrdgtohhmqeenucggtffrrghtthgvrhhnpeevgedtffelffelveeuleelgfejfeevvdejhfehgeefgfffvdefteegvedutefftdenucfkphepvdgrtddumegtsgduleemkegugeehmeegledttdemieehieekmedvlegsudemlegvfhehmegvkegtjeenucevlhhushhtvghrufhiiigvpedufeenucfrrghrrghmpehinhgvthepvdgrtddumegtsgduleemkegugeehmeegledttdemieehieekmedvlegsudemlegvfhehmegvkegtjedphhgvlhhopehfvgguohhrrgdrhhhomhgvpdhmrghilhhfrhhomhepmhgrgihimhgvrdgthhgvvhgrlhhlihgvrhessghoohhtlhhinhdrtghomhdpnhgspghrtghpthhtohepfedupdhrtghpthhtohepuggrvhgvmhesuggrvhgvmhhlohhfthdrnhgvthdprhgtphhtthhopehmrgigihhmvgdrtghhvghvrghllhhivghrsegsohhothhlihhnrdgtohhmpdhrtghpthhtohepnhgvthguvghvsehvghgvrhdrk hgvrhhnvghlrdhorhhgpdhrtghpthhtoheplhhinhhugidqkhgvrhhnvghlsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtoheplhhinhhugidqrghrmhdqmhhsmhesvhhgvghrrdhkvghrnhgvlhdrohhrghdprhgtphhtthhopehthhhomhgrshdrphgvthgriiiiohhnihessghoohhtlhhinhdrtghomhdprhgtphhtthhopegrnhgurhgvfieslhhunhhnrdgthhdprhgtphhtthhopehkuhgsrgeskhgvrhhnvghlrdhorhhg X-GND-Sasl: maxime.chevallier@bootlin.com X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250717_003049_806875_5FA8920A X-CRM114-Status: GOOD ( 20.03 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org This documentation aims at describing the main goal of the phy_port infrastructure. Signed-off-by: Maxime Chevallier --- Documentation/networking/index.rst | 1 + Documentation/networking/phy-port.rst | 111 ++++++++++++++++++++++++++ MAINTAINERS | 1 + 3 files changed, 113 insertions(+) create mode 100644 Documentation/networking/phy-port.rst diff --git a/Documentation/networking/index.rst b/Documentation/networking/index.rst index ac90b82f3ce9..f60acc06e3f7 100644 --- a/Documentation/networking/index.rst +++ b/Documentation/networking/index.rst @@ -96,6 +96,7 @@ Contents: packet_mmap phonet phy-link-topology + phy-port pktgen plip ppp_generic diff --git a/Documentation/networking/phy-port.rst b/Documentation/networking/phy-port.rst new file mode 100644 index 000000000000..6d9d46ebe438 --- /dev/null +++ b/Documentation/networking/phy-port.rst @@ -0,0 +1,111 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. _phy_port: + +================= +Ethernet ports +================= + +This document is a basic description of the phy_port infrastructure, +introduced to represent physical interfaces of Ethernet devices. + +Without phy_port, we already have quite a lot of information about what the +media-facing interface of a NIC can do and looks like, through the +:c:type:`struct ethtool_link_ksettings ` attributes, +which includes : + + - What the NIC can do through the :c:member:`supported` field + - What the Link Partner advertises through :c:member:`lp_advertising` + - Which features we're advertising through :c:member:`advertising` + +We also have info about the number of lanes and the PORT type. These settings +are built by aggregating together information reported by various devices that +are sitting on the link : + + - The NIC itself, through the :c:member:`get_link_ksettings` callback + - Precise information from the MAC and PCS by using phylink in the MAC driver + - Information reported by the PHY device + - Information reported by an SFP module (which can itself include a PHY) + +This model however starts showing its limitations when we consider devices that +have more than one media interface. In such a case, only information about the +actively used interface is reported, and it's not possible to know what the +other interfaces can do. In fact, we have very few information about whether or +not there are any other media interfaces. + +The goal of the phy_port representation is to provide a way of representing a +physical interface of a NIC, regardless of what is driving the port (NIC through +a firmware, SFP module, Ethernet PHY). + +Multi-port interfaces examples +============================== + +Several cases of multi-interface NICs have been observed so far : + +Internal MII Mux:: + + +------------------+ + | SoC | + | +-----+ | +-----+ + | +-----+ | |-------------| PHY | + | | MAC |--| Mux | | +-----+ +-----+ + | +-----+ | |-----| SFP | + | +-----+ | +-----+ + +------------------+ + +Internal Mux with internal PHY:: + + +------------------------+ + | SoC | + | +-----+ +-----+ + | +-----+ | |-| PHY | + | | MAC |--| Mux | +-----+ +-----+ + | +-----+ | |-----------| SFP | + | +-----+ | +-----+ + +------------------------+ + +External Mux:: + + +---------+ + | SoC | +-----+ +-----+ + | | | |--| PHY | + | +-----+ | | | +-----+ + | | MAC |----| Mux | +-----+ + | +-----+ | | |--| PHY | + | | +-----+ +-----+ + | | | + | GPIO-------+ + +---------+ + +Double-port PHY:: + + +---------+ + | SoC | +-----+ + | | | |--- RJ45 + | +-----+ | | | + | | MAC |---| PHY | +-----+ + | +-----+ | | |---| SFP | + +---------+ +-----+ +-----+ + +phy_port aims at providing a path to support all the above topologies, by +representing the media interfaces in a way that's agnostic to what's driving +the interface. the struct phy_port object has its own set of callback ops, and +will eventually be able to report its own ksettings:: + + _____ +------+ + ( )-----| Port | + +-----+ ( ) +------+ + | MAC |--( ??? ) + +-----+ ( ) +------+ + (_____)-----| Port | + +------+ + +Next steps +========== + +As of writing this documentation, only ports controlled by PHY devices are +supported. The next steps will be to add the Netlink API to expose these +to userspace and add support for raw ports (controlled by some firmware, and directly +managed by the NIC driver). + +Another parallel task is the introduction of a MII muxing framework to allow the +control of non-PHY driver multi-port setups. diff --git a/MAINTAINERS b/MAINTAINERS index 2317e420c311..8fcb43cce415 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -8965,6 +8965,7 @@ F: Documentation/devicetree/bindings/net/ethernet-connector.yaml F: Documentation/devicetree/bindings/net/ethernet-phy.yaml F: Documentation/devicetree/bindings/net/mdio* F: Documentation/devicetree/bindings/net/qca,ar803x.yaml +F: Documentation/networking/phy-port.rst F: Documentation/networking/phy.rst F: drivers/net/mdio/ F: drivers/net/mdio/acpi_mdio.c -- 2.49.0