Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751997AbdINVBl (ORCPT ); Thu, 14 Sep 2017 17:01:41 -0400 Received: from vps0.lunn.ch ([185.16.172.187]:43787 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751562AbdINVBk (ORCPT ); Thu, 14 Sep 2017 17:01:40 -0400 Date: Thu, 14 Sep 2017 23:01:32 +0200 From: Andrew Lunn To: Alexander Duyck Cc: Maxim Uvarov , Vivien Didelot , Greg KH , netdev , "linux-kernel@vger.kernel.org" , kernel@savoirfairelinux.com, "David S. Miller" , Florian Fainelli , Egil Hjelmeland , John Crispin , Woojung Huh , Sean Wang , Nikita Yushchenko , Chris Healy Subject: Re: [PATCH net-next v2 01/10] net: dsa: add debugfs interface Message-ID: <20170914210132.GC3084@lunn.ch> References: <20170828191748.19492-1-vivien.didelot@savoirfairelinux.com> <20170828191748.19492-2-vivien.didelot@savoirfairelinux.com> <20170907193434.GA11006@kroah.com> <87h8wdb8bj.fsf@weeman.i-did-not-set--mail-host-address--so-tickle-me> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1249 Lines: 28 > Can you clarify what type of registers it is you are wanting to read? > We already have ethtool which is meant to allow reading the device > registers for a given netdev. As long as the port has a netdev > associated it then there is no need to be getting into debugfs since > we should probably just be using ethtool. Not all ports of a DSA switch have a netdev. This is by design. The presentation we gave to Netdev 2.1 gives some of the background. Plus a switch has a lot of registers not associated to port. Often a switch has more global registers than port registers. > Also as Jiri pointed out there is already devlink which would probably > be a better way to get the associated information for those pieces > that don't have a netdev associated with them. We have looked at the devlink a few times. The current dpipe code is not generic enough. It makes assumptions about the architecture of the switch, that it is all match/action based. The niche of top of rack switches might be like that, but average switches are not. If dpipe was to support simple generic two dimensional tables, we probably would use it. David suggested making a class device for DSA. It is not ideal, but we are probably going to go that way. Andrew