From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jose Abreu <Jose.Abreu@synopsys.com>
Subject: Re: [RFC] ethtool: Support for driver private ioctl's
Date: Fri, 6 Apr 2018 14:57:26 +0100
Message-ID: <c9e4f4a4-bf58-6272-943e-5eeadeefdaa9@synopsys.com>
References: <cbd05f37-509b-118b-e681-0ccd0ebebd73@synopsys.com>
 <df7773c4-8695-38dd-bedd-39b88f4aaec1@gmail.com>
 <20180406090702.mgzozmkkh3vuhe7w@unicorn.suse.cz>
Mime-Version: 1.0
Content-Type: text/plain; charset="windows-1252"
Content-Transfer-Encoding: 7bit
Cc: Florian Fainelli <f.fainelli@gmail.com>,
        Jose Abreu <Jose.Abreu@synopsys.com>,
        David Miller <davem@redhat.com>,
        Jakub Jelinek <jj@ultra.linux.cz>,
        Jeff Garzik <jgarzik@pobox.com>, Tim Hockin <thockin@sun.com>,
        Eli Kupermann <eli.kupermann@intel.com>,
        Chris Leech <christopher.leech@intel.com>,
        Scott Feldman <scott.feldman@intel.com>,
        "Ben Hutchings" <ben@decadent.org.uk>,
        Joao Pinto <Joao.Pinto@synopsys.com>
To: Michal Kubecek <mkubecek@suse.cz>, <netdev@vger.kernel.org>
Return-path: <netdev-owner@vger.kernel.org>
Received: from smtprelay4.synopsys.com ([198.182.47.9]:45828 "EHLO
        smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1753120AbeDFN5d (ORCPT
        <rfc822;netdev@vger.kernel.org>); Fri, 6 Apr 2018 09:57:33 -0400
In-Reply-To: <20180406090702.mgzozmkkh3vuhe7w@unicorn.suse.cz>
Sender: netdev-owner@vger.kernel.org
List-ID: <netdev.vger.kernel.org>

Hi Michal,

On 06-04-2018 10:07, Michal Kubecek wrote:
> On Thu, Apr 05, 2018 at 08:50:49AM -0700, Florian Fainelli wrote:
>> On 04/05/2018 03:47 AM, Jose Abreu wrote:
>>> Background: Synopsys Ethernet IP's have a certain number of
>>> features which can be reconfigured at runtime. Giving you two
>>> examples: One of the most recent one is the safety features,
>>> which can be enabled/disabled and forced at runtime. Another one
>>> is a Flexible RX Parser which can route specific packets to
>>> specific RX DMA channels. Given that these are features specific
>>> to our IP's it would not be useful to add an uniform API for this
>>> because the users would only be one or two drivers ...
>> Parsing of packets and directing the matched packets to specific
>> queues/channels can be done through ethtool rxnfc API, tc/cls_flower as
>> well, so you should really check whether those APIs don't already allow
>> you to do what you want.
>>
>> ethtool already supports a concept of private  flags, not ioctl() though
>> which allows you to toggle boolean values for instance (or technically
>> up to how many bits a "flag" is used to represent) is that enough or do
>> you need to turn on/off the feature as well as pass configuration
>> parameters?
> Perhaps introducing "driver/device specific tunables" (i.e. something
> like tunables or PHY tunables but specific to a particular device) could
> be a way. But it could get out of control quickly and users wouldn't be
> happy if they had to set the same (or almost the same) parameter under
> five different names for five NIC vendors.

Yeah, that wouldn't be good but I think this should be a
responsibility to developer: To see if there is an existing
API/ethtool entry before implementing the "tunable". I think a
big concern, for me at least, is that ethtool already has a lot
of options and introducing even more would lead the user to
confusion ...

Thanks and Best Regards,
Jose Miguel Abreu

>
> Michal Kubecek