Re: [RFC 2/3] net: Provide switchdev driver for NXP's More Than IP L2 switch

From: Andrew Lunn <andrew@lunn.ch>
To: Lukasz Majewski <lukma@denx.de>
Cc: "David S . Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Madalin Bucur <madalin.bucur@oss.nxp.com>,
	Nicolas Ferre <nicolas.ferre@microchip.com>,
	Joakim Zhang <qiangqing.zhang@nxp.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Vladimir Oltean <olteanv@gmail.com>,
	netdev@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
	Mark Einon <mark.einon@gmail.com>,
	NXP Linux Team <linux-imx@nxp.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC 2/3] net: Provide switchdev driver for NXP's More Than IP L2 switch
Date: Fri, 25 Jun 2021 16:40:21 +0200	[thread overview]
Message-ID: <YNXq1bp7XH8jRyx0@lunn.ch> (raw)
In-Reply-To: <20210625115935.132922ff@ktm>

> I do believe that I can just extend the L2 switch driver (fec_mtip.c
> file to be precise) to provide full blown L2 switch functionality
> without touching the legacy FEC more than in this patch set.
> 
> Would you consider applying this patch series then?

What is most important is the ABI. If something is merged now, we need
to ensure it does not block later refactoring to a clean new
driver. The DT binding is considered ABI. So the DT binding needs to
be like a traditional switchdev driver. Florian already pointed out,
you can use a binding very similar to DSA. ti,cpsw-switch.yaml is
another good example.

So before considering merging your changes, i would like to see a
usable binding.

I also don't remember seeing support for STP. Without that, your
network has broadcast storm problems when there are loops. So i would
like to see the code needed to put ports into blocking, listening,
learning, and forwarding states.

	  Andrew