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=-5.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 449A2C433E0 for ; Mon, 8 Jun 2020 16:08:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1F91F2063A for ; Mon, 8 Jun 2020 16:08:12 +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="0WRHvJzJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730516AbgFHQIL (ORCPT ); Mon, 8 Jun 2020 12:08:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57582 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730357AbgFHQIK (ORCPT ); Mon, 8 Jun 2020 12:08:10 -0400 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:3201:214:fdff:fe10:1be6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CB631C08C5C2; Mon, 8 Jun 2020 09:08:08 -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=7VoRl6qQlPxAENq4swBjnhUVEexaLc0WppnAtA1JmcY=; b=0WRHvJzJToSgd8Xjgr1TW5lNh f6sbLcPfQYlR930Di+98noAUh6OtZQe7W6tdF6mQgk3nI3Of8xrxCVr8ots3PjNSAuSaGxDPlB5+a UZ3dzCTg/NReHWAwOA/J1G49dKJtwWy8u0XbEGN/XncsysEekP+B5WOP0+96wJ2SmnwIWBov2+QLY PeEfH4tSH0f4AZfr8n16AhQaXDXP/8lpYc4QjE+MpNYTG5fygyCk4ISApJJ/VXtWutflbFMcbPhoB WYDkjXyaopMoJI+WASx25CpQynsHz75ghL4IRBZmFlCn/uV1SkeUnMCGTxjsge7bQRG4NsdRY9ZhC dOQyVdQhQ==; Received: from shell.armlinux.org.uk ([2001:4d48:ad52:3201:5054:ff:fe00:4ec]:51000) by pandora.armlinux.org.uk with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jiKJf-0000c8-OJ; Mon, 08 Jun 2020 17:08:03 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1jiKJd-0002CW-W7; Mon, 08 Jun 2020 17:08:02 +0100 Date: Mon, 8 Jun 2020 17:08:01 +0100 From: Russell King - ARM Linux admin To: Sascha Hauer Cc: netdev@vger.kernel.org, devicetree@vger.kernel.org, kernel@pengutronix.de, linux-kernel@vger.kernel.org, Thomas Petazzoni , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] net: ethernet: mvneta: add support for 2.5G DRSGMII mode Message-ID: <20200608160801.GO1551@shell.armlinux.org.uk> References: <20200608074716.9975-1-s.hauer@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200608074716.9975-1-s.hauer@pengutronix.de> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 08, 2020 at 09:47:16AM +0200, Sascha Hauer wrote: > The Marvell MVNETA Ethernet controller supports a 2.5 Gbps SGMII mode > called DRSGMII. > > This patch adds a corresponding phy-mode string 'drsgmii' and parses it > from DT. The MVNETA then configures the SERDES protocol value > accordingly. > > It was successfully tested on a MV78460 connected to a FPGA. Digging around, this is Armada XP? Which SoCs is this mode supported? There's no mention of DRSGMII in the A38x nor A37xx documentation which are later than Armada XP. What exactly is "drsgmii"? It can't be "double-rate" SGMII because that would give you 2Gbps max instead of the 1Gbps, but this gives 2.5Gbps, so I'm really not sure using "drsgmii" is a good idea. It may be what Marvell call it, but we really need to know if there's some vendor neutral way to refer to it. > Signed-off-by: Sascha Hauer > --- > .../devicetree/bindings/net/ethernet-controller.yaml | 1 + > drivers/net/ethernet/marvell/mvneta.c | 7 ++++++- > include/linux/phy.h | 3 +++ > 3 files changed, 10 insertions(+), 1 deletion(-) > > This patch has already been sent 3 years ago here: > https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20170123142206.5390-1-jlu@pengutronix.de/ > Since then the driver has evolved a lot. 2.5Gbps is properly configured in the > MAC now. Nevertheless, adding a new interface mode needs properly documenting to describe exactly what it is - see Documentation/networking/phy.rst, the section "PHY interface modes". The above point about "what is this" illustrates why we need these documented. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTC for 0.8m (est. 1762m) line in suburbia: sync at 13.1Mbps down 424kbps up 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=-5.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 9EE33C433E0 for ; Mon, 8 Jun 2020 16:08:43 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 4ECA42063A for ; 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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Jun 08, 2020 at 09:47:16AM +0200, Sascha Hauer wrote: > The Marvell MVNETA Ethernet controller supports a 2.5 Gbps SGMII mode > called DRSGMII. > > This patch adds a corresponding phy-mode string 'drsgmii' and parses it > from DT. The MVNETA then configures the SERDES protocol value > accordingly. > > It was successfully tested on a MV78460 connected to a FPGA. Digging around, this is Armada XP? Which SoCs is this mode supported? There's no mention of DRSGMII in the A38x nor A37xx documentation which are later than Armada XP. What exactly is "drsgmii"? It can't be "double-rate" SGMII because that would give you 2Gbps max instead of the 1Gbps, but this gives 2.5Gbps, so I'm really not sure using "drsgmii" is a good idea. It may be what Marvell call it, but we really need to know if there's some vendor neutral way to refer to it. > Signed-off-by: Sascha Hauer > --- > .../devicetree/bindings/net/ethernet-controller.yaml | 1 + > drivers/net/ethernet/marvell/mvneta.c | 7 ++++++- > include/linux/phy.h | 3 +++ > 3 files changed, 10 insertions(+), 1 deletion(-) > > This patch has already been sent 3 years ago here: > https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20170123142206.5390-1-jlu@pengutronix.de/ > Since then the driver has evolved a lot. 2.5Gbps is properly configured in the > MAC now. Nevertheless, adding a new interface mode needs properly documenting to describe exactly what it is - see Documentation/networking/phy.rst, the section "PHY interface modes". The above point about "what is this" illustrates why we need these documented. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTC for 0.8m (est. 1762m) line in suburbia: sync at 13.1Mbps down 424kbps up _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel