Re: [PATCH 0/2] add Ethernet driver support for mt2712

From: Jose Abreu <Jose.Abreu@synopsys.com>
To: Andrew Lunn <andrew@lunn.ch>,
	Biao Huang <biao.huang@mediatek.com>, <peppe.cavallaro@st.com>,
	<alexandre.torgue@st.com>, <Jose.Abreu@synopsys.com>
Cc: <davem@davemloft.net>, <robh+dt@kernel.org>,
	<honghui.zhang@mediatek.com>, <yt.shen@mediatek.com>,
	<liguo.zhang@mediatek.com>, <mark.rutland@arm.com>,
	<sean.wang@mediatek.com>, <nelson.chang@mediatek.com>,
	<matthias.bgg@gmail.com>, <netdev@vger.kernel.org>,
	<devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-mediatek@lists.infradead.org>
Subject: Re: [PATCH 0/2] add Ethernet driver support for mt2712
Date: Mon, 17 Sep 2018 17:18:14 +0100	[thread overview]
Message-ID: <a8c0a091-6bee-6504-04cd-36e214e805aa@synopsys.com> (raw)
In-Reply-To: <20180917152441.GD5458@lunn.ch>

Hi Andrew, Biao,

On 17-09-2018 16:24, Andrew Lunn wrote:
> On Mon, Sep 17, 2018 at 02:29:21PM +0800, Biao Huang wrote:
>
> Adding in the STMMAC driver maintainers.
>
>> Ethernet in mt2712 is totally different from that in
>> drivers/net/ethernet/mediatek/*, so we add new folder for mt2712 SoC.
>>
>> The mt2712 Ethernet IP is from Synopsys, and we notice that there is a
>> reference driver in drivers/net/ethernet/synopsys/*. But
>> 1. our version is only for 10/100/1000Mbps, not for 2.5/4/5Gbps.
>> mt2712 Ethernet design is differnet from that in synopsys folder in many
>> aspects, and some key features are not included in mt2712, such as rss
>> and split header. At the same time, some features we need have not been
>> implenmented in synopsys folder.
> In general, we don't have two very similar drivers. We try to have one
> driver. If the problem was just missing features in the stmmac driver,
> you can add them. I doubt not supporting 2.5/4/5Gbps in your silicon
> is an issue, since very few STMMAC devices have this. By split header,
> do you mean support for TSO? That seems to be a gmac4 or newer
> feature, but the driver supports not having tso support in hardware.
>
> Giuseppe, Alexandre, Jose: Please can you look at the proposed driver
> and see how much it really differs from the STMMAC driver. 

Thanks for the cc Andrew, indeed this looks very similar and the
register bank matches, by what I've seen, GMAC 4+.

> How easy
> would it be to extend stmmac it to support the mt2712?

Very easy, as I've just done with XGMAC2. If Biao wants to expand
stmmac functionality I'm all in favor!

Thanks and Best Regards,
Jose Miguel Abreu

>
> Thanks
> 	Andrew