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Date:   Tue, 28 Nov 2023 11:20:37 +0100
From:   Maxime Chevallier <maxime.chevallier@bootlin.com>
To:     Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc:     davem@davemloft.net, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, Jakub Kicinski <kuba@kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        Paolo Abeni <pabeni@redhat.com>,
        linux-arm-kernel@lists.infradead.org,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        Jose Abreu <joabreu@synopsys.com>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Simon Horman <horms@kernel.org>,
        linux-stm32@st-md-mailman.stormreply.com,
        alexis.lothore@bootlin.com
Subject: Re: [PATCH net] net: stmmac: dwmac-socfpga: Don't access SGMII
 adapter when not available
Message-ID: <20231128112037.21e2d5aa@device.home>
In-Reply-To: <20231128101841.627fc97e@windsurf>
References: <20231128094538.228039-1-maxime.chevallier@bootlin.com>
        <20231128101841.627fc97e@windsurf>
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Hello Thomas,

On Tue, 28 Nov 2023 10:18:41 +0100
Thomas Petazzoni <thomas.petazzoni@bootlin.com> wrote:

> On Tue, 28 Nov 2023 10:45:37 +0100
> Maxime Chevallier <maxime.chevallier@bootlin.com> wrote:
> 
> > The SGMII adapter isn't present on all dwmac-socfpga implementations.
> > Make sure we don't try to configure it if we don't have this adapter.
> > 
> > Fixes: 5d1f3fe7d2d5 ("net: stmmac: dwmac-sogfpga: use the lynx pcs driver")
> > Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
> > ---
> >  drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
> > index ba2ce776bd4d..ae120792e1b6 100644
> > --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
> > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
> > @@ -243,7 +243,8 @@ static void socfpga_sgmii_config(struct socfpga_dwmac *dwmac, bool enable)
> >  {
> >  	u16 val = enable ? SGMII_ADAPTER_ENABLE : SGMII_ADAPTER_DISABLE;
> >  
> > -	writew(val, dwmac->sgmii_adapter_base + SGMII_ADAPTER_CTRL_REG);
> > +	if (dwmac->sgmii_adapter_base)
> > +		writew(val, dwmac->sgmii_adapter_base + SGMII_ADAPTER_CTRL_REG);
> >  }
> >  
> >  static int socfpga_set_phy_mode_common(int phymode, u32 *val)  
> 
> Reviewed-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
> 
> As a follow-up improvement, there's an open-coded version of
> socfpga_sgmii_config() in socfpga_dwmac_fix_mac_speed(), which could be
> rewritten as such:
> 
> 	socfpga_sgmii_config(dwmac, false);
>
> 	if (splitter_base) {
> 		val = readl(splitter_base + EMAC_SPLITTER_CTRL_REG);
> 		val &= ~EMAC_SPLITTER_CTRL_SPEED_MASK;
 [...]

I did saw this, but as this is merely a non-functional rework, I'd
like to target this to net-next, so I'll wait for the fix to land and
follow-up with this rework indeed.

Thanks for the review,

Maxime