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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 ABD37C433E0 for ; Wed, 27 May 2020 07:01:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8FA31207CB for ; Wed, 27 May 2020 07:01:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728873AbgE0HBD convert rfc822-to-8bit (ORCPT ); Wed, 27 May 2020 03:01:03 -0400 Received: from relay2-d.mail.gandi.net ([217.70.183.194]:62379 "EHLO relay2-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726025AbgE0HBC (ORCPT ); Wed, 27 May 2020 03:01:02 -0400 X-Originating-IP: 90.76.143.236 Received: from localhost (lfbn-tou-1-1075-236.w90-76.abo.wanadoo.fr [90.76.143.236]) (Authenticated sender: antoine.tenart@bootlin.com) by relay2-d.mail.gandi.net (Postfix) with ESMTPSA id F1F1940009; Wed, 27 May 2020 07:00:59 +0000 (UTC) Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT In-Reply-To: <20200526170100.GM768009@lunn.ch> References: <20200526162256.466885-1-antoine.tenart@bootlin.com> <20200526170100.GM768009@lunn.ch> To: Andrew Lunn Subject: Re: [PATCH net-next 0/4] net: phy: mscc-miim: reduce waiting time between MDIO transactions From: Antoine Tenart Cc: davem@davemloft.net, f.fainelli@gmail.com, hkallweit1@gmail.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, alexandre.belloni@bootlin.com, thomas.petazzoni@bootlin.com, allan.nielsen@microchip.com Message-ID: <159056285904.265465.1821646548974311512@kwain> Date: Wed, 27 May 2020 09:00:59 +0200 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Andrew, Quoting Andrew Lunn (2020-05-26 19:01:00) > On Tue, May 26, 2020 at 06:22:52PM +0200, Antoine Tenart wrote: > > > > This series aims at reducing the waiting time between MDIO transactions > > when using the MSCC MIIM MDIO controller. > > There are a couple of other things you can look at: > > Can you disable the pre-amble on the MDIO transaction. It requires > that both the bus master and all devices on the bus support it, but > when it is usable, you half the number of bits sent over the wire. > > Can you control the frequency of MDC? 802.3 says 2.5MHz, but many > devices support higher speeds. Again, you need all devices on the bus > to support the speed. > > When accessing raw TDR data for cable tests i also have a lot of PHY > accesses. I implemented both of these for the FEC MDIO bus, and made > it a lot faster. Thanks for the tips! Antoine -- Antoine Ténart, Bootlin Embedded Linux and Kernel engineering https://bootlin.com