From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiri Pirko Subject: Re: sfc userland MCDI - request for guidance Date: Sat, 16 Jan 2016 11:03:09 +0100 Message-ID: <20160116100309.GB2129@nanopsycho.orion> References: <56992D8C.7090003@solarflare.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev , linux-net-drivers To: Edward Cree Return-path: Received: from mail-wm0-f67.google.com ([74.125.82.67]:34438 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751097AbcAPKDM (ORCPT ); Sat, 16 Jan 2016 05:03:12 -0500 Received: by mail-wm0-f67.google.com with SMTP id b14so7054079wmb.1 for ; Sat, 16 Jan 2016 02:03:11 -0800 (PST) Content-Disposition: inline In-Reply-To: <56992D8C.7090003@solarflare.com> Sender: netdev-owner@vger.kernel.org List-ID: Fri, Jan 15, 2016 at 06:34:04PM CET, ecree@solarflare.com wrote: >I have a design problem with a few possible solutions and I'd like some > guidance on which ones would be likely to be acceptable. > >The sfc driver communicates with the hardware using a protocol called MCDI - > Management Controller to Driver Interface - and for various reasons > (ranging from test automation to configuration utilities) we would like to > be able to do this from userspace. We currently have two ways of handling > this, neither of which is satisfactory. It is wrong to send commands to HW directly to userspace. Please, do proper in-kernel vendor neutral feature abstraction and the implement in your driver. That is how things work. Userspace->HW bypass is simply unacceptable.