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=-5.3 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 A330BC433DF for ; Wed, 29 Jul 2020 10:58:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7D72820663 for ; Wed, 29 Jul 2020 10:58:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="NWWsEXP7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726533AbgG2K6K (ORCPT ); Wed, 29 Jul 2020 06:58:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55356 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726299AbgG2K6K (ORCPT ); Wed, 29 Jul 2020 06:58:10 -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 D37EAC061794 for ; Wed, 29 Jul 2020 03:58:09 -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=YwHcAo8JtZ8pPTU5tNcYUhAKmdKCD95vxiiMjQq4OJs=; b=NWWsEXP7dYzMqa7tTgE70CU26 3aAjrSgaFYKfgpk5wHMWI1DF54sEtQvd3z6AfQS9H7qup1WyPcHAdjFdOgcokY0v0LXKjvYNMd9/P 9i5GLPNiW2LEMV/p75vhyWxXEl7XAbL1QWCQXPx3Cw7gsaQbM1gfIxH/k+qN278mORypQNYuMu1ip +x15iHQVxnZQ4oxC+r31SLrLRNNZqa+Gw46iJw8UP2Hq8NYKkWBHPKZQg1HkeUZa7EjK4ZN3lzOsN j6qLwHWjf/7EkWai/iiPtXcupMiDhcySwHexOJXXfWG/MHU1heVT1OTvR8TNhVm/xhJxCBdqUCaeM Pmtc88sFg==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:45644) by pandora.armlinux.org.uk with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1k0jmh-0005J6-SS; Wed, 29 Jul 2020 11:58:07 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1k0jmh-0005cX-9w; Wed, 29 Jul 2020 11:58:07 +0100 Date: Wed, 29 Jul 2020 11:58:07 +0100 From: Russell King - ARM Linux admin To: Richard Cochran , Andrew Lunn , Florian Fainelli , Heiner Kallweit Cc: "David S. Miller" , Jakub Kicinski , netdev@vger.kernel.org Subject: Re: [PATCH RFC net-next] net: phy: add Marvell PHY PTP support Message-ID: <20200729105807.GZ1551@shell.armlinux.org.uk> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, Jul 14, 2020 at 05:26:28PM +0100, Russell King wrote: > Add PTP basic support for Marvell 88E151x PHYs. These PHYs support > timestamping the egress and ingress of packets, but does not support > any packet modification, nor do we support any filtering beyond > selecting packets that the hardware recognises as PTP/802.1AS. A question has come up concerning the selection of PTP timestamping sources within a network device. I have the situation on a couple of devices where there are multiple places that can do PTP timestamping: - the PHY (slow to access, only event capture which may not be wired, doesn't seem to synchronise well - delay of 58000, frequency changes every second between +/-1500ppb.) - the Ethernet MAC (fast to access, supports event capture and trigger generation which also may not be wired, synchronises well, delay of 700, frequency changes every second +/- 40ppb.) How do we deal with this situation - from what I can see from the ethtool API, we have to make a choice about which to use. How do we make that choice? It's not a case of "just implement one" since hardware may have both available on a particular ethernet interface or just one available. Do we need a property to indicate whether we wish to use the PHY or MAC PTP stamping, or something more elaborate? -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!