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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id B76E0C77B60 for ; Mon, 3 Apr 2023 08:33:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=c0LElPzHvIJBXAUtUo4b2Lr+6Ah/1gGRLH7qQf37Wso=; b=cG0jIR5pU65WaR 6ApgOOnS4z5bYI/AMWIgMtDZrvEgQhhixotwHu6jo7HSy9yrA+ET+t0HsAkDsDuxxL/yt9tPGaQOD bQ6zDUhhonsVHcRR6RzrqskmLDobKLGfQMo9Fz1Fie8mYwXEi3jUB8cgWlAP/HVCRKk00v9CD5/qC q+ykVbNl62eE4upSjqTYvuWoMMXbe8yv+9nl3uwM7oSdqQbWD9H64ILwBf7up8P6GsFDh8xcLxBi2 yZC2cjDrV38oIX7Kh5IalJ2MlFJT7EvXb/jG7dQ/TVAAKLBMtJCCwE5eho5Mu6LhfT9UdqUyVMU3G xOqi4uLukQwJijugUNFw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pjFcQ-00EXaQ-2U; Mon, 03 Apr 2023 08:32:50 +0000 Received: from pandora.armlinux.org.uk ([2001:4d48:ad52:32c8:5054:ff:fe00:142]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1pjFcK-00EXX6-26 for linux-arm-kernel@lists.infradead.org; Mon, 03 Apr 2023 08:32:49 +0000 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=01gayVV3++Wf58D2nrigu1LyEW250ZpuC9pqh/U9RlA=; b=mtoKptTHdC8YSa2GcFbmSs0PhN uf2NXfVTDV+4bzJ2P7+iarjijbx/r5Tx//zCtL030LbKB2SxHY/2yvGeje/QW1s5SvhH7mdTCyNZU 7EyoODvszE6IMXoECN+HvNvgtwcnpWES5Up7VsDFAyEYmafZrXz9s7BIZEPcezKr+z8guK0+oI6Sb wpr0Af4+ZSbfW+nPRbqUGni7zsqlM0WS6LRgi3Dcn6ZMpKOxF+dw2+iwJ5x8vnclu2XKVJ8a0evhd OGVLjdHYgL9DmAKI8L99FeD0YRkev8r9Sr6h3AQbITut4KZn6IjR9gyqgkSEOosFe7C6weBKiRlBC Ot9TSWag==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:55416) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1pjFc5-0002OO-P7; Mon, 03 Apr 2023 09:32:29 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1pjFc4-00044E-2P; Mon, 03 Apr 2023 09:32:28 +0100 Date: Mon, 3 Apr 2023 09:32:28 +0100 From: "Russell King (Oracle)" To: Siddharth Vadapalli Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, rogerq@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, srk@ti.com Subject: Re: [PATCH net-next 2/2] net: ethernet: ti: am65-cpsw: Enable USXGMII mode for J784S4 CPSW9G Message-ID: References: <20230331065110.604516-3-s-vadapalli@ti.com> <54c3964b-5dd8-c55e-08db-61df4a07797c@ti.com> <7a9c96f4-6a94-4a2c-18f5-95f7246e10d5@ti.com> <1477e0c3-bb92-72b0-9804-0393c34571d3@ti.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230403_013244_850604_B25902B0 X-CRM114-Status: GOOD ( 38.15 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Apr 03, 2023 at 11:57:21AM +0530, Siddharth Vadapalli wrote: > Hello Russell, > > On 31/03/23 19:16, Siddharth Vadapalli wrote: > > > > > > On 31-03-2023 16:42, Russell King (Oracle) wrote: > >> On Fri, Mar 31, 2023 at 04:23:16PM +0530, Siddharth Vadapalli wrote: > >>> > >>> > >>> On 31/03/23 15:16, Russell King (Oracle) wrote: > >>>> On Fri, Mar 31, 2023 at 02:55:56PM +0530, Siddharth Vadapalli wrote: > >>>>> Russell, > >>>>> > >>>>> On 31/03/23 13:54, Russell King (Oracle) wrote: > >>>>>> On Fri, Mar 31, 2023 at 01:35:10PM +0530, Siddharth Vadapalli wrote: > >>>>>>> Hello Russell, > >>>>>>> > >>>>>>> Thank you for reviewing the patch. > >>>>>>> > >>>>>>> On 31/03/23 13:27, Russell King (Oracle) wrote: > >>>>>>>> On Fri, Mar 31, 2023 at 12:21:10PM +0530, Siddharth Vadapalli wrote: > >>>>>>>>> TI's J784S4 SoC supports USXGMII mode. Add USXGMII mode to the > >>>>>>>>> extra_modes member of the J784S4 SoC data. Additionally, configure the > >>>>>>>>> MAC Control register for supporting USXGMII mode. Also, for USXGMII > >>>>>>>>> mode, include MAC_5000FD in the "mac_capabilities" member of struct > >>>>>>>>> "phylink_config". > >>>>>>>> > >>>>>>>> I don't think TI "get" phylink at all... > >>>>>>>> > >>>>>>>>> diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c > >>>>>>>>> index 4b4d06199b45..ab33e6fe5b1a 100644 > >>>>>>>>> --- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c > >>>>>>>>> +++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c > >>>>>>>>> @@ -1555,6 +1555,8 @@ static void am65_cpsw_nuss_mac_link_up(struct phylink_config *config, struct phy > >>>>>>>>> mac_control |= CPSW_SL_CTL_GIG; > >>>>>>>>> if (interface == PHY_INTERFACE_MODE_SGMII) > >>>>>>>>> mac_control |= CPSW_SL_CTL_EXT_EN; > >>>>>>>>> + if (interface == PHY_INTERFACE_MODE_USXGMII) > >>>>>>>>> + mac_control |= CPSW_SL_CTL_XGIG | CPSW_SL_CTL_XGMII_EN; > >>>>>>>> > >>>>>>>> The configuration of the interface mode should *not* happen in > >>>>>>>> mac_link_up(), but should happen in e.g. mac_config(). > >>>>>>> > >>>>>>> I will move all the interface mode associated configurations to mac_config() in > >>>>>>> the v2 series. > >>>>>> > >>>>>> Looking at the whole of mac_link_up(), could you please describe what > >>>>>> effect these bits are having: > >>>>>> > >>>>>> CPSW_SL_CTL_GIG > >>>>>> CPSW_SL_CTL_EXT_EN > >>>>>> CPSW_SL_CTL_IFCTL_A > >>>>> > >>>>> CPSW_SL_CTL_GIG corresponds to enabling Gigabit mode (full duplex only). > >>>>> CPSW_SL_CTL_EXT_EN when set enables in-band mode of operation and when cleared > >>>>> enables forced mode of operation. > >>>>> CPSW_SL_CTL_IFCTL_A is used to set the RMII link speed (0=10 mbps, 1=100 mbps). > >>>> > >>>> Okay, so I would do in mac_link_up(): > >>>> > >>>> /* RMII needs to be manually configured for 10/100Mbps */ > >>>> if (interface == PHY_INTERFACE_MODE_RMII && speed == SPEED_100) > >>>> mac_control |= CPSW_SL_CTL_IFCTL_A; > >>>> > >>>> if (speed == SPEED_1000) > >>>> mac_control |= CPSW_SL_CTL_GIG; > >>>> if (duplex) > >>>> mac_control |= CPSW_SL_CTL_FULLDUPLEX; > >>>> > >>>> I would also make mac_link_up() do a read-modify-write operation to > >>>> only affect the bits that it is changing. > >>> > >>> This is the current implementation except for the SGMII mode associated > >>> operation that I had recently added. I will fix that. Also, the > >>> cpsw_sl_ctl_set() function which writes the mac_control value performs a read > >>> modify write operation. > >>> > >>>> > >>>> Now, for SGMII, I would move setting CPSW_SL_CTL_EXT_EN to mac_config() > >>>> to enable in-band mode - don't we want in-band mode enabled all the > >>>> time while in SGMII mode so the PHY gets the response from the MAC? > >>> > >>> Thank you for pointing it out. I will move that to mac_config(). > >>> > >>>> > >>>> Lastly, for RGMII at 10Mbps, you seem to suggest that you need RGMII > >>>> in-band mode enabled for that - but if you need RGMII in-band for > >>>> 10Mbps, wouldn't it make sense for the other speeds as well? If so, > >>>> wouldn't that mean that CPSW_SL_CTL_EXT_EN can always be set for > >>>> RGMII no matter what speed is being used? > >>> > >>> The CPSW MAC does not support forced mode at 10 Mbps RGMII. For this reason, if > >>> RGMII 10 Mbps is requested, it is set to in-band mode. > >> > >> What I'm saying is that if we have in-band signalling that is reliable > >> for a particular interface mode, why not always use it, rather than > >> singling out one specific speed as an exception? Does it not work in > >> 100Mbps and 1Gbps? > > While the CPSW MAC supports RGMII in-band status operation, the link partner > might not support it. I have also observed that forced mode is preferred to > in-band mode as implemented for another driver: > commit ade64eb5be9768e40c90ecb01295416abb2ddbac > net: dsa: microchip: Disable RGMII in-band status on KSZ9893 > > and in the mail thread at: > https://lore.kernel.org/netdev/20200905160647.GJ3164319@lunn.ch/ > based on Andrew's suggestion, using forced mode appears to be better. > > Additionally, I have verified that switching to in-band status causes a > regression. Thus, I will prefer keeping it in forced mode for 100 and 1000 Mbps > RGMII mode which is the existing implementation in the driver. Please let me know. Okay, so what this seems to mean is if you have a PHY that does not support in-band status in RGMII mode, then 10Mbps isn't possible - because the MAC requires in-band status mode to select 10Mbps. To put it another way, in such a combination, 10Mbps link modes should not be advertised, nor should they be reported to userspace as being supported. Is that correct? -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last! _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel