Re: [PATCH] net: phy: marvell: Fix RGMII Tx/Rx delays setting in 88e1121-compatible PHYs

[Serge Semin]

+Cc: Heiner, Russel, David, Jakub

-Sergey

On Fri, Feb 04, 2022 at 08:29:11AM +0300, Пархоменко Павел Кириллович wrote:
> It is mandatory for a software to issue a reset upon modifying RGMII
> Receive Timing Control and RGMII Transmit Timing Control bit fields of MAC
> Specific Control register 2 (page 2, register 21) otherwise the changes
> won't be perceived by the PHY (the same is applicable for a lot of other
> registers). Not setting the RGMII delays on the platforms that imply
> it's being done on the PHY side will consequently cause the traffic loss.
> We discovered that the denoted soft-reset is missing in the
> m88e1121_config_aneg() method for the case if the RGMII delays are
> modified but the MDIx polarity isn't changed or the auto-negotiation is
> left enabled, thus causing the traffic loss on our platform with Marvell
> Alaska 88E1510 installed. Let's fix that by issuing the soft-reset if the
> delays have been actually set in the m88e1121_config_aneg_rgmii_delays()
> method.
> 
> Fixes: d6ab93364734 ("net: phy: marvell: Avoid unnecessary soft reset")
> Signed-off-by: Pavel Parkhomenko <Pavel.Parkhomenko@xxxxxxxxxxxxxxxxxxxx>
> Reviewed-by: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx>
> Cc: Alexey Malahov <Alexey.Malahov@xxxxxxxxxxxxxxxxxxxx>
> Cc: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx>
> Cc: netdev@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> 
> ---
>  drivers/net/phy/marvell.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/phy/marvell.c b/drivers/net/phy/marvell.c
> index 4fcfca4e1702..a4f685927a64 100644
> --- a/drivers/net/phy/marvell.c
> +++ b/drivers/net/phy/marvell.c
> @@ -551,9 +551,9 @@ static int m88e1121_config_aneg_rgmii_delays(struct
> phy_device *phydev)
>  	else
>  		mscr = 0;
>  
> -	return phy_modify_paged(phydev, MII_MARVELL_MSCR_PAGE,
> -				MII_88E1121_PHY_MSCR_REG,
> -				MII_88E1121_PHY_MSCR_DELAY_MASK, mscr);
> +	return phy_modify_paged_changed(phydev, MII_MARVELL_MSCR_PAGE,
> +					MII_88E1121_PHY_MSCR_REG,
> +					MII_88E1121_PHY_MSCR_DELAY_MASK, mscr);
>  }
>  
>  static int m88e1121_config_aneg(struct phy_device *phydev)
> @@ -567,11 +567,13 @@ static int m88e1121_config_aneg(struct phy_device *phydev)
>  			return err;
>  	}
>  
> +	changed = err;
> +
>  	err = marvell_set_polarity(phydev, phydev->mdix_ctrl);
>  	if (err < 0)
>  		return err;
>  
> -	changed = err;
> +	changed |= err;
>  
>  	err = genphy_config_aneg(phydev);
>  	if (err < 0)
> -- 
> 2.34.1
> 
>