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=-8.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,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 77A12C433DF for ; Wed, 17 Jun 2020 10:55:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5472B214DB for ; Wed, 17 Jun 2020 10:55:34 +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="ERBCM48N" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726642AbgFQKzd (ORCPT ); Wed, 17 Jun 2020 06:55:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54056 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725894AbgFQKzc (ORCPT ); Wed, 17 Jun 2020 06:55:32 -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 7602FC061573 for ; Wed, 17 Jun 2020 03:55:32 -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=KtF7AHwx+IWjHeMNIIoYJUSw5kkF6TtU7N5IVTw4PmQ=; b=ERBCM48Nxul+mEUwO3o2Vdpqd e/lt3DWi96iiW6MiXKNzQ0B/gtX58paP1c+DC5gSW6AzYx66+7I34o1PwmGuASM/2e3Is79WM0OnE g/b870l7bGSomDyKAHhZIxQS7mLtgSoQzMCYoxmgqsLWYAPhZiz303xxgVAPzcuzd+cLYnHpAoblZ Y1n+SIo8M/gThlCBhhJoKYYOS0TVOxM4JVB+3WAyRQDNnPc2MxyxHOXV9HFRcq3MUartnn4Hxvazy Sb+q0MbvJ4FhzsKSL3MmcyaZ+rwZv6ZMhGrdm3k8o6s9siEbCJgse9QCXjJJqRnCoI1nv3f7PQ7lG sBGDdxT5A==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:58442) by pandora.armlinux.org.uk with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jlVj0-0003dJ-3V; Wed, 17 Jun 2020 11:55:22 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1jlViw-0003fF-Df; Wed, 17 Jun 2020 11:55:18 +0100 Date: Wed, 17 Jun 2020 11:55:18 +0100 From: Russell King - ARM Linux admin To: Helmut Grohne Cc: Nicolas Ferre , "David S. Miller" , Jakub Kicinski , Palmer Dabbelt , Paul Walmsley , netdev@vger.kernel.org Subject: Re: [PATCH] net: macb: reject unsupported rgmii delays Message-ID: <20200617105518.GO1551@shell.armlinux.org.uk> References: <20200616074955.GA9092@laureti-dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200616074955.GA9092@laureti-dev> 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, Jun 16, 2020 at 09:49:56AM +0200, Helmut Grohne wrote: > The macb driver does not support configuring rgmii delays. At least for > the Zynq GEM, delays are not supported by the hardware at all. However, > the driver happily accepts and ignores any such delays. > > When operating in a mac to phy connection, the delay setting applies to > the phy. Since the MAC does not support delays, the phy must provide > them and the only supported mode is rgmii-id. However, in a fixed mac > to mac connection, the delay applies to the mac itself. Therefore the > only supported rgmii mode is rgmii. This seems incorrect - see the phy documentation in Documentation/networking/phy.rst: * PHY_INTERFACE_MODE_RGMII: the PHY is not responsible for inserting any internal delay by itself, it assumes that either the Ethernet MAC (if capable or the PCB traces) insert the correct 1.5-2ns delay * PHY_INTERFACE_MODE_RGMII_TXID: the PHY should insert an internal delay for the transmit data lines (TXD[3:0]) processed by the PHY device * PHY_INTERFACE_MODE_RGMII_RXID: the PHY should insert an internal delay for the receive data lines (RXD[3:0]) processed by the PHY device * PHY_INTERFACE_MODE_RGMII_ID: the PHY should insert internal delays for both transmit AND receive data lines from/to the PHY device Note that PHY_INTERFACE_MODE_RGMII, the delay can be added by _either_ the MAC or by PCB trace routing. The individual RGMII delay modes are more about what the PHY itself is asked to do with respect to inserting delays, so I don't think your patch makes sense. In any case... > Link: https://lore.kernel.org/netdev/20200610081236.GA31659@laureti-dev/ > Signed-off-by: Helmut Grohne > --- > drivers/net/ethernet/cadence/macb_main.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c > index 5b9d7c60eebc..bee5bf65e8b3 100644 > --- a/drivers/net/ethernet/cadence/macb_main.c > +++ b/drivers/net/ethernet/cadence/macb_main.c > @@ -514,7 +514,7 @@ static void macb_validate(struct phylink_config *config, > state->interface != PHY_INTERFACE_MODE_RMII && > state->interface != PHY_INTERFACE_MODE_GMII && > state->interface != PHY_INTERFACE_MODE_SGMII && > - !phy_interface_mode_is_rgmii(state->interface)) { > + state->interface != PHY_INTERFACE_MODE_RGMII_ID) { Here you reject everything except PHY_INTERFACE_MODE_RGMII_ID. > bitmap_zero(supported, __ETHTOOL_LINK_MODE_MASK_NBITS); > return; > } > @@ -694,6 +694,13 @@ static int macb_phylink_connect(struct macb *bp) > struct phy_device *phydev; > int ret; > > + if (of_phy_is_fixed_link(dn) && > + phy_interface_mode_is_rgmii(bp->phy_interface) && > + bp->phy_interface != PHY_INTERFACE_MODE_RGMII) { but here you reject everything except PHY_INTERFACE_MODE_RGMII. These can't both be right. If you start with PHY_INTERFACE_MODE_RGMII, and have a fixed link, you'll have PHY_INTERFACE_MODE_RGMII passed into the validate function, which will then fail. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!