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=-2.1 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 0E695C43218 for ; Mon, 10 Jun 2019 21:11:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D1D8C20820 for ; Mon, 10 Jun 2019 21:11:45 +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="iPeeqdfV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389714AbfFJVLm (ORCPT ); Mon, 10 Jun 2019 17:11:42 -0400 Received: from vps0.lunn.ch ([185.16.172.187]:42924 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726663AbfFJVLl (ORCPT ); Mon, 10 Jun 2019 17:11:41 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Sender: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=haNK3T2ZntFCRUM4zV1ClpWgl70cpyViZTlgMWG58Ik=; b=iPeeqdfVe8RjXjJ/ONYpk8FHS6 t6xnvjAKjL2id1j8rgCoooi2T1HQNClxc5PbT1SaY/mVRxh3Wbc3HMNHcaqT6+Nb8tLCB5v6j3YlB dGqYuT6cbjheL4AeUj90MHpBZu3VUpq5zg4L4KhL3Uc2tqTc9NVdTQNFxpUbwYqP58BI=; Received: from andrew by vps0.lunn.ch with local (Exim 4.89) (envelope-from ) id 1haRZl-0001xt-T0; Mon, 10 Jun 2019 23:11:33 +0200 Date: Mon, 10 Jun 2019 23:11:33 +0200 From: Andrew Lunn To: Vladimir Oltean Cc: Florian Fainelli , netdev , Ioana Ciornei , Russell King , Vivien Didelot , "David S. Miller" , open list Subject: Re: [PATCH net-next] net: dsa: Deal with non-existing PHY/fixed-link Message-ID: <20190610211133.GC2191@lunn.ch> References: <20190610193150.22231-1-f.fainelli@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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 > Hi Florian, > > Can you give an example of when this is a valid use case, and why > fixed-link is not appropriate? A DSA link is used to connect two switches together. ZII devel b and c are two boards which does this. Such links have the MACs connected back to back, no PHYs involved. You can also connect a SoC interface to the CPU port of a switch without having PHYs involved. We have defined that CPU and DSA ports are always configured by the driver to there maximum speed. Because of this, you often don't need a fixed-link on CPU or DSA ports. So you will see most DT blobs don't have any sort of PHY for the CPU or DSA ports. You only need fixed-link when you need to slow a port down, e.g. a SoC FE port connected to a switch 1G port. Andrew