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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 76C49C6FA8E for ; Thu, 2 Mar 2023 17:23:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229764AbjCBRXZ (ORCPT ); Thu, 2 Mar 2023 12:23:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33914 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229758AbjCBRXY (ORCPT ); Thu, 2 Mar 2023 12:23:24 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 545F01C7DD for ; Thu, 2 Mar 2023 09:23:23 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D60706160D for ; Thu, 2 Mar 2023 17:23:22 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D3DD0C433A0; Thu, 2 Mar 2023 17:23:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1677777802; bh=QlUaI9YM2OKoLqI5rk+BPrX+1XMc8It7bT4E9dfu2FA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=r5RA0F8l+kjTseXyormEX4PoTnyY+ocn+H+97+bx09/yw4L+TiC42tyrqlZBLP8Qx ObdF9gAQtUszItUafKybe2UN6ckUU55HiaJw0U7llsCII2e3RNePwRnKBQtrlWkoud yV+SN8ERjjI13V3RJPhsPZW1+ehAzvfQEPwP2Zt3gS+y7W+BZ6Um8R0hC7vysrFXr+ w3+QvG6h1uutUOlNSPBvPM0LSuBAVdd6LDPzI9/ROd8M3pnXn5b1EknZkSAIuEgf07 RGFWrii/xxg6jPpmv0wKLIpfzCpYh7l19k5dzN8DcZ8vzDeZbSw7xeTNthdrvtIseY fYhjTlmGIm/7w== Date: Thu, 2 Mar 2023 09:23:20 -0800 From: Jakub Kicinski To: =?UTF-8?B?S8O2cnk=?= Maincent Cc: "Russell King (Oracle)" , Richard Cochran , andrew@lunn.ch, davem@davemloft.net, f.fainelli@gmail.com, hkallweit1@gmail.com, netdev@vger.kernel.org, Thomas Petazzoni , Maxime Chevallier Subject: Re: [PATCH RFC net-next] net: phy: add Marvell PHY PTP support [multicast/DSA issues] Message-ID: <20230302092320.6ee8eb6d@kernel.org> In-Reply-To: <20230302180616.7bcfc1ef@kmaincent-XPS-13-7390> References: <20230228141630.64d5ef63@kmaincent-XPS-13-7390> <20230228142648.408f26c4@kernel.org> <20230228145911.2df60a9f@kernel.org> <20230301170408.0cc0519d@kmaincent-XPS-13-7390> <20230302084932.4e242f71@kernel.org> <20230302180616.7bcfc1ef@kmaincent-XPS-13-7390> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, 2 Mar 2023 18:06:16 +0100 K=C3=B6ry Maincent wrote: > I have measured it with the Marvell PHY and MACB MAC but it is the contra= ry on > my side: > https://lkml.kernel.org/netdev/20230302113752.057a3213@kmaincent-XPS-13-7= 390/ > Also PHY default seems more logical as it is nearer to the physical link,= but > still I am interesting by the answer as I am not a PTP expert. Is really = PTP > MAC often more precise than PTP PHY? Do you happen to have a datasheet for MACB? The time stamping capability is suspiciously saved in a variable called hw_dma_cap which may indicate it's a DMA time stamp not a true PTP stamp. Quite a few NICs/MACs support DMA time stamps because it's far=20 easier to take the stamp where the descriptor writing logic is (DMA block) than take it at the end of the MAC and haul it all=20 the way thru the pipeline back to the DMA block.