From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Roese Subject: Problem with am335x (cpsw) MDIO state machine Date: Fri, 22 Nov 2013 17:06:08 +0100 Message-ID: <528F80F0.7010003@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: "netdev@vger.kernel.org" To: Mugunthan V N Return-path: Received: from mo-p05-ob.rzone.de ([81.169.146.181]:10682 "EHLO mo-p05-ob.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755801Ab3KVQGO (ORCPT ); Fri, 22 Nov 2013 11:06:14 -0500 Sender: netdev-owner@vger.kernel.org List-ID: Hi All! I'm currently struggling with the MDIO interface of the am335x SoC. As its state machine continuously communicates with the potentially available PHY devices (0...31). To determine the link status etc. But I'm trying to communicate with am SMSC9303 switch via this MDIO interface. It has 32bit registers organized as 2 16bit registers. These registers need to be accessed back-to-back. Without any other frame in between. And this is often interrupted (disturbed) by these state machines polling frames. Has anyone ever tried to work in this SoC with this MDIO state machine disabled? I tried this by clearing the ENABLE bit in the MDIOCONTROL register after each transaction. But this doesn't seem to work (resulting in timeouts etc)? Has anybody ever tried anything like this? Thanks, Stefan