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From:   Amit Tomer <amittomer25@gmail.com>
Date:   Mon, 28 Jun 2021 13:55:40 +0530
Message-ID: <CABHD4K_r_ixtBXH_v82S62onYr-=fbh8cHJsdz0oo6MN-i5tVg@mail.gmail.com>
Subject: Re: [PATCH v3 2/3] net: ethernet: actions: Add Actions Semi Owl
 Ethernet MAC driver
To:     Cristian Ciocaltea <cristian.ciocaltea@gmail.com>
Cc:     Florian Fainelli <f.fainelli@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Andrew Lunn <andrew@lunn.ch>, Jakub Kicinski <kuba@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        =?UTF-8?Q?Andreas_F=C3=A4rber?= <afaerber@suse.de>,
        Manivannan Sadhasivam <mani@kernel.org>,
        Philipp Zabel <p.zabel@pengutronix.de>, netdev@vger.kernel.org,
        devicetree@vger.kernel.org,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        linux-actions@lists.infradead.org, linux-kernel@vger.kernel.org
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Hi,

> > Do you know the story behind this Ethernet controller?
>
> I just happened to get a board based on the S500 SoC, so I took this
> opportunity to help improving the mainline kernel support, but other
> than that I do not really know much about the hardware history.
>
> > The various
> > receive/transmit descriptor definitions are 99% those defined in
> > drivers/net/ethernet/stmmicro/stmmac/descs.h for the normal descriptor.
>
> That's an interesting observation. I could only assume the vendor did
> not want to reinvent the wheel here, but I cannot say if this is a
> common design scheme or is something specific to STMicroelectronics
> only.

I am not entirely sure about it but it looks like it *may* only need
to have a glue driver to
connect to DWMAC.
For instance, on the U-boot[1] side (S700 is one of 64bit OWL SoC from
actions), we kind of re-uses already
existing DWMAC and provide a glue code, and on the Linux side as well
have some similar implementation (locally).

Thanks
-Amit.

[1]: https://source.denx.de/u-boot/u-boot/-/blob/master/drivers/net/dwmac_s700.c