RE: [PATCH, net] phy: aquantia: Fix AN when higher speeds than 1G are not advertised

From: Claudiu Manoil <claudiu.manoil@nxp.com>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Heiner Kallweit <hkallweit1@gmail.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Russell King <linux@armlinux.org.uk>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	Ondrej Spacek <ondrej.spacek@nxp.com>
Subject: RE: [PATCH, net] phy: aquantia: Fix AN when higher speeds than 1G are not advertised
Date: Sat, 11 Jun 2022 18:13:12 +0000	[thread overview]
Message-ID: <AM9PR04MB8397DF04A87E32E6B7E690E096A99@AM9PR04MB8397.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <YqSt5Rysq110xpA3@lunn.ch>

> -----Original Message-----
> From: Andrew Lunn <andrew@lunn.ch>
> Sent: Saturday, June 11, 2022 6:00 PM
[...]
> Subject: Re: [PATCH, net] phy: aquantia: Fix AN when higher speeds than 1G are
> not advertised
> 
> On Fri, Jun 10, 2022 at 11:40:37AM +0300, Claudiu Manoil wrote:
> > Even when the eth port is resticted to work with speeds not higher than 1G,
> > and so the eth driver is requesting the phy (via phylink) to advertise up
> > to 1000BASET support, the aquantia phy device is still advertising for 2.5G
> > and 5G speeds.
> > Clear these advertising defaults when requested.
> 
> Hi Claudiu
> 
> genphy_c45_an_config_aneg(phydev) is called in aqr_config_aneg, which
> should set/clear MDIO_AN_10GBT_CTRL_ADV5G and
> MDIO_AN_10GBT_CTRL_ADV2_5G. Does the aQuantia PHY not have these bits?
> 

Hi Andrew,

Apparently it's not enough to clear the 7.20h register (aka MDIO_AN_10GBT_CTRL)
to stop AQR advertising for higher speeds, otherwise I wouldn't have bothered with
the patch.

We have AQR113c and AQR107 phys on 3 board types, 2 firmware versions for the phys,
but for every instance the AQR phys auto-negotiate at 2.5G when phydev->advertising
is set to 1G, or even 5G when phydev->advertising is set to 2.5G (for the port that supports
2.5G).

Do you have any board with any AQR phy (I think they are called AQrate Gen3 PHYs)?
Have you tried to restrict phydev->advertising to 1G and connect to a link partner that
has 2.5G capability?
At least in our case the link is always resolved to 2.5G unless we set the 7.C400h register
as shown in this patch.

Thanks.
Claudiu  