Re: [PATCH net-next v2 10/10] net: stmmac: Add DW XPCS specified via "pcs-handle" support

From: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Serge Semin <fancer.lancer@gmail.com>
Cc: Andrew Lunn <andrew@lunn.ch>, Tomer Maimon <tmaimon77@gmail.com>,
	Alexandre Torgue <alexandre.torgue@foss.st.com>,
	Eric Dumazet <edumazet@google.com>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Sagar Cheluvegowda <quic_scheluve@quicinc.com>,
	linux-stm32@st-md-mailman.stormreply.com,
	Florian Fainelli <f.fainelli@gmail.com>,
	openbmc@lists.ozlabs.org,
	Maxime Chevallier <maxime.chevallier@bootlin.com>,
	Jose Abreu <joabreu@synopsys.com>,
	Abhishek Chauhan <quic_abchauha@quicinc.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Andrew Halaney <ahalaney@redhat.com>,
	Jose Abreu <Jose.Abreu@synopsys.com>,
	devicetree@vger.kernel.org, Conor Dooley <conor+dt@kernel.org>,
	Jiawen Wu <jiawenwu@trustnetic.com>,
	linux-arm-kernel@lists.infradead.org,
	Mengyuan Lou <mengyuanlou@net-swift.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	Rob Herring <robh+dt@kernel.org>,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>,
	Vladimir Oltean <olteanv@gmail.com>,
	"Da vid S. Miller" <davem@davemloft.net>,
	Heiner Kallweit <hkallweit1@gmail.com>
Subject: Re: [PATCH net-next v2 10/10] net: stmmac: Add DW XPCS specified via "pcs-handle" support
Date: Mon, 3 Jun 2024 10:03:54 +0100	[thread overview]
Message-ID: <Zl2G+gK8qpBjGpb3@shell.armlinux.org.uk> (raw)
In-Reply-To: <2lpomvxhmh7bxqhkuexukztwzjfblulobepmnc4g4us7leldgp@o3a3zgnpua2a>

On Mon, Jun 03, 2024 at 11:54:22AM +0300, Serge Semin wrote:
> >  	if (priv->plat->pcs_init) {
> >  		ret = priv->plat->pcs_init(priv);
> 
> > +	} else if (fwnode_property_present(devnode, "pcs-handle")) {
> > +		pcsnode = fwnode_find_reference(devnode, "pcs-handle", 0);
> > +		xpcs = xpcs_create_fwnode(pcsnode, mode);
> > +		fwnode_handle_put(pcsnode);
> > +		ret = PTR_ERR_OR_ZERO(xpcs);
> 
> Just figured, we might wish to be a bit more portable in the
> "pcs-handle" property semantics implementation seeing there can be at
> least three different PCS attached:
> DW XPCS
> Lynx PCS
> Renesas RZ/N1 MII
> 
> Any suggestion of how to distinguish the passed handle? Perhaps
> named-property, phandle argument, by the compatible string or the
> node-name?

I can't think of a reasonable solution to this at the moment. One
solution could be pushing this down into the platform code to deal
with as an interim solution, via the new .pcs_init() method.

We could also do that with the current XPCS code, since we know that
only Intel mGBE uses xpcs. This would probably allow us to get rid
of the has_xpcs flag.

-- 
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