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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham 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 74B36C28CC0 for ; Thu, 30 May 2019 14:48:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 45DDC238F9 for ; Thu, 30 May 2019 14:48:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="rflj/enl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726664AbfE3OsJ (ORCPT ); Thu, 30 May 2019 10:48:09 -0400 Received: from mail-ed1-f68.google.com ([209.85.208.68]:38372 "EHLO mail-ed1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725897AbfE3OsI (ORCPT ); Thu, 30 May 2019 10:48:08 -0400 Received: by mail-ed1-f68.google.com with SMTP id g13so9509678edu.5; Thu, 30 May 2019 07:48:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=C9E51ZhwTVP2YDkKNnHyBwrwMch4rhjQofN8cIkB4Wk=; b=rflj/enlljMqqWL5Fspgm/IFob3rkrZIcEFvxHqEO1GO8OoyGwHQlbM788bklcYMkD yfDX9H1WXd7dtD0biy5Maaumln3ywPLCa1NUJDvq1V40EVmeg4CIX2B6Lxp/tkrueZXr QpeD1Sdp7S7oPmgwWADz1VkUBA74XY/5H7hPikSFfEIw6Oa8TjSewUN/q0snPYuUP2di R59LNpF2R7Pl8fUsGebhbchrImCuEyO38JQWj+50rhWwdUcv0sdH6807dTrA6yB2keTW EM6BjegcWMACoE9vkFo0ILBjjd71mnP1ssz2Bj38NtQq2nAl1GG/ar2qb1i5416nH62t zCBg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=C9E51ZhwTVP2YDkKNnHyBwrwMch4rhjQofN8cIkB4Wk=; b=kBzvILv0MDb23Ob83IzOILT9eqOD9n1kR6pUxt+iEae+4uim5UN7pgjOIHsKaBN7yM IyIJ20f/wJPOXk4QS2mavW3WhWTeW+mCJ7LDMYS0BkLtH4WCpXIqcUSF/MOsfEC8n49C Vj2CNUxYaFetEegqCu78qesDwy3qBxaQL14lcODP1zBw5p7SKv+1VfP4XDTP+i/8GOyj EGtPL8sKAX6eC+vAevZJ/lH8MzI3N3fOQTvVxs3L9GaYrv2LRf3h/btnnRTsdLkmakew lTWQsSzMXPDsQ1nDnBSWVGW90RyzKUR4s2cb1rEKMx1ebpupEx33yJojJsZhM6InkhEz OUcg== X-Gm-Message-State: APjAAAXTZm1XkbEGZawf2fvsSBj/ipKYnGBFdB3PN/rK74uiLF8DVtGf rGW7bC0qb47wfy1aP2LFZCYzlw038dluk9/s7Ow= X-Google-Smtp-Source: APXvYqwGgVx8dH1DO0bkYjO/Mjf0Bdl50l/INQBcBiPlW8sHmh9iDs4hd6EHSw/TBd5FH+hBST3PqZKxt4PRDLJ1ri0= X-Received: by 2002:a17:906:5855:: with SMTP id h21mr3907379ejs.15.1559227686918; Thu, 30 May 2019 07:48:06 -0700 (PDT) MIME-Version: 1.0 References: <20190528235627.1315-1-olteanv@gmail.com> <20190528235627.1315-4-olteanv@gmail.com> <20190529044912.cyg44rqvdo73oeiu@localhost> <20190530035112.qbn3nnoxrgum7anz@localhost> <20190530142356.vxkhsjalxfytvx2c@localhost> In-Reply-To: <20190530142356.vxkhsjalxfytvx2c@localhost> From: Vladimir Oltean Date: Thu, 30 May 2019 17:47:55 +0300 Message-ID: Subject: Re: [PATCH net-next 3/5] net: dsa: mv88e6xxx: Let taggers specify a can_timestamp function To: Richard Cochran Cc: Florian Fainelli , Vivien Didelot , Andrew Lunn , "David S. Miller" , John Stultz , Thomas Gleixner , Stephen Boyd , lkml , netdev Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 30 May 2019 at 17:24, Richard Cochran wrote: > > On Thu, May 30, 2019 at 10:42:41AM +0300, Vladimir Oltean wrote: > > The meta frames generated by the SJA1105 do not contain any seqid. > > So this cannot ever work... > > > They contain: > > * A globally programmable DMAC > > * A globally programmable SMAC > > Don't know what these are, but doesn't sound like they uniquely > identify the original frame. > > > * The 0x8 EtherType > > * A partial (24-bit or 32-bit) RX timestamp > > * Two bytes from the initial (pre follow-up) frame's DMAC, before the > > switch mangled those with the source port and switch id. The driver is > > supposed to patch these bytes from the follow-up back into the initial > > frame before passing them up the stack. > > * The source port that generated the meta frame > > * The switch id that generated the meta frame > > None of these match to the original frame uniquely. Looks like this > is a dead end. > Yes, they don't identify the original frame. The hardware's line of thinking seems to be "The meta frame is sent immediately after the trapped frame that triggered the action." (quote from https://www.nxp.com/docs/en/user-guide/UM10944.pdf). > I recommend forgetting about these meta frames. Instead, read out the > time stamps over MDIO. > If there was any other way to retrieve RX timestamps I would have done it already. > Thanks, > Richard