From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from vps0.lunn.ch (vps0.lunn.ch [156.67.10.101]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C05A52BE033; Tue, 2 Dec 2025 13:36:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=156.67.10.101 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764682613; cv=none; b=AccLlu45GsfwuTamrii4Q96UA9DQ11d2VeO9OI6sVK+2H7DljiSA67QJ0g1job22hpE9u1oGEKxHmg5zF49xFz7vK++WMc7SKSluUNnsH0vJIhHRk4UK9GZMDU2SF0W7e5foP3y3ZYOpBBsq6yZvo4jyDC/4+goUbi6iaQs8mlg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764682613; c=relaxed/simple; bh=fdhup/S/zrXpJWaUcDkcxNrD2Cwp5IAQxDToERCP1nI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=GuzJ477PwwfLSfX3c6PR+2VSOvSHfST7oEn98jTsOei3ivmg+Xp8vSfq/a26RRhkLENPhFafALfaJ9Qc+ijdij0a3+s75+dOt8FFPyolkxSLQOEEJtd83yppQh79DoIo4M0FG6SUrCZskGwiDT+mD523uUzIBx79E6SrtAS0URI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lunn.ch; spf=pass smtp.mailfrom=lunn.ch; dkim=pass (1024-bit key) header.d=lunn.ch header.i=@lunn.ch header.b=VC9d/UAn; arc=none smtp.client-ip=156.67.10.101 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lunn.ch Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lunn.ch Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=lunn.ch header.i=@lunn.ch header.b="VC9d/UAn" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Disposition:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:From:Sender:Reply-To:Subject: Date:Message-ID:To:Cc:MIME-Version:Content-Type:Content-Transfer-Encoding: Content-ID:Content-Description:Content-Disposition:In-Reply-To:References; bh=1Wpx9IjkcuCXJrN+lvoQ0/PWGUe4eWqI7yjH11ZhMTc=; b=VC9d/UAnse+naHpZdifFVmTv3e 21BAnHhjw8HPGF19RKmyVaDfCX6uHMOxsibeLkKxh5KZZeEQwS0ZaR2Ua03HSCUyahL8vElefUN41 iBZxxnp/a8B+iPeb1ShSxBRSNEViUIygvNlf3anjA6FMYUa0PzxmLXuwq5Uhc3Ct54bE=; Received: from andrew by vps0.lunn.ch with local (Exim 4.94.2) (envelope-from ) id 1vQQY7-00FhXN-UW; Tue, 02 Dec 2025 14:36:11 +0100 Date: Tue, 2 Dec 2025 14:36:11 +0100 From: Andrew Lunn To: Jacky Chou Cc: Tao Ren , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Po-Yu Chuang , Joel Stanley , Andrew Jeffery , "netdev@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-aspeed@lists.ozlabs.org" , "taoren@meta.com" Subject: Re: [PATCH net-next v4 4/4] net: ftgmac100: Add RGMII delay support for AST2600 Message-ID: <4f0e4aa0-166d-4a7f-b91e-42dbc6b832e5@lunn.ch> References: <68f10ee1-d4c8-4498-88b0-90c26d606466@lunn.ch> <3af52caa-88a7-4b88-bd92-fd47421cc81a@lunn.ch> <041e23a2-67e6-4ebb-aee5-14400491f99c@lunn.ch> <1c2ace4e-f3bb-4efa-a621-53c3711f46cb@lunn.ch> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: > Hi Andrew, > > I miss one condition is using fixed-link property. > In ftgmac100, there are RGMII, NC-SI and fixed-link property. > On RGMII, we have solution on dedicated PHY, but there is an issue on fixed-link > property. > > Example on dedicated PHY. > The driver can pass the "rgmii-id" to tell PHY driver to enable the internal delay on > PHY side. Therefore, we can force to disable RGMII delay on MAC side. > But there is not any driver when using fixed-link property, which means > no body can tell the outside device, like switch or MAC-to-MAC, to enable the internal > delay on them. Also mean the phy-mode in fixed-link case is not used. > > Therefore, could we ignore the RGMII delay on MAC side when the ftgmac100 driver gets > the fixed-link property? Just keep the original delay value? MAC to MAC is one of the edge cases where phy-mode is not great. What is generally accepted it to use rx-internal-delay-ps and tx-internal-delay-ps with 2ns and a comment explaining it is a MAC to MAC link, with this MAC adding the delays. I suggest you see how messy it is to implement this for 2600. If the code looks horrible, keep the bootloader delays. For 2700 you have a clean slate, you can implement all this correctly from the start. Andrew