Date:   Fri, 10 Feb 2023 12:52:56 +0000
From:   Daniel Golle <daniel@makrotopia.org>
To:     "Russell King (Oracle)" <linux@armlinux.org.uk>
Cc:     netdev@vger.kernel.org, linux-mediatek@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Lorenzo Bianconi <lorenzo@kernel.org>,
        Mark Lee <Mark-MC.Lee@mediatek.com>,
        John Crispin <john@phrozen.org>, Felix Fietkau <nbd@nbd.name>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        DENG Qingfang <dqfext@gmail.com>,
        Landen Chao <Landen.Chao@mediatek.com>,
        Sean Wang <sean.wang@mediatek.com>,
        Paolo Abeni <pabeni@redhat.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        "David S. Miller" <davem@davemloft.net>,
        Vladimir Oltean <olteanv@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Andrew Lunn <andrew@lunn.ch>,
        Jianhui Zhao <zhaojh329@gmail.com>,
        =?iso-8859-1?Q?Bj=F8rn?= Mork <bjorn@mork.no>
Subject: Re: [PATCH v2 11/11] net: dsa: mt7530: use external PCS driver
Message-ID: <Y+Y+KHXnGUgroYQ/@makrotopia.org>
References: <cover.1675779094.git.daniel@makrotopia.org>
 <dcda0a3a1bf89e27e600822df63009b2b10e136a.1675779094.git.daniel@makrotopia.org>
 <Y+Yi+ajKHaLo4Vvq@shell.armlinux.org.uk>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <Y+Yi+ajKHaLo4Vvq@shell.armlinux.org.uk>
Precedence: bulk

On Fri, Feb 10, 2023 at 10:56:57AM +0000, Russell King (Oracle) wrote:
> On Tue, Feb 07, 2023 at 02:24:17PM +0000, Daniel Golle wrote:
> > @@ -2728,11 +2612,11 @@ mt753x_phylink_mac_select_pcs(struct dsa_switch *ds, int port,
> >  
> >  	switch (interface) {
> >  	case PHY_INTERFACE_MODE_TRGMII:
> > +		return &priv->pcs[port].pcs;
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

> >  	case PHY_INTERFACE_MODE_SGMII:
> >  	case PHY_INTERFACE_MODE_1000BASEX:
> >  	case PHY_INTERFACE_MODE_2500BASEX:
> > -		return &priv->pcs[port].pcs;
> > -
> > +		return priv->ports[port].sgmii_pcs;
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> 
> My only concern here is that we also use the PCS when in TRGMII mode in
> this driver, but the mtk pcs code from mtk_eth_soc doesn't handle
> TRGMII (and getting the link timer will fail for this mode, causing
> the pcs_config() method to fail.)
> 
> Thus, this driver will stop working in TRGMII mode.

But in TRGMII mode we return &priv->pcs[port].pcs which is not the PCS
code from mtk_eth_soc now moved to the new pcs-mtk-lynxi driver, but
rather the old existing codepath from mt7530.c.

The new PCS driver only replaces mt7531_sgmii_pcs_* functions, which
were all nearly identical with what is now in pcs-mtk-lynxi.c.

Or do I miss something here?