Re: [RFC PATCH net-next] net: mvneta: deny disabling autoneg for 802.3z modes

[Marek Behun <marek.behun@nic.cz>]

On Mon, 12 Jul 2021 16:47:16 +0100
"Russell King (Oracle)" <rmk+kernel@armlinux.org.uk> wrote:

> The documentation for Armada 38x says:
> 
>   Bit 2 Field InBandAnEn In-band Auto-Negotiation enable. ...
>   When <PortType> = 1 (1000BASE-X) this field must be set to 1.
> 
> We presently ignore whether userspace requests autonegotiation or not
> through the ethtool ksettings interface. However, we have some network
> interfaces that wish to do this. To offer a consistent API across
> network interfaces, deny the ability to disable autonegotiation on
> mvneta hardware when in 1000BASE-X and 2500BASE-X.
> 
> This means the only way to switch between 2500BASE-X and 1000BASE-X
> on SFPs that support this will be:
> 
>  # ethtool -s ethX advertise 0x20000002000 # 1000BASE-X Pause
>  # ethtool -s ethX advertise 0xa000        # 2500BASE-X Pause
> 
> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
> ---
> net-next is currently closed, but I'd like to collect acks for this
> patch. Thanks.
> 
>  drivers/net/ethernet/marvell/mvneta.c | 20 ++++++++++++++------
>  1 file changed, 14 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
> index 361bc4fbe20b..0a35d216b742 100644
> --- a/drivers/net/ethernet/marvell/mvneta.c
> +++ b/drivers/net/ethernet/marvell/mvneta.c
> @@ -3832,12 +3832,20 @@ static void mvneta_validate(struct phylink_config *config,
>  	struct mvneta_port *pp = netdev_priv(ndev);
>  	__ETHTOOL_DECLARE_LINK_MODE_MASK(mask) = { 0, };
>  
> -	/* We only support QSGMII, SGMII, 802.3z and RGMII modes */
> -	if (state->interface != PHY_INTERFACE_MODE_NA &&
> -	    state->interface != PHY_INTERFACE_MODE_QSGMII &&
> -	    state->interface != PHY_INTERFACE_MODE_SGMII &&
> -	    !phy_interface_mode_is_8023z(state->interface) &&
> -	    !phy_interface_mode_is_rgmii(state->interface)) {
> +	/* We only support QSGMII, SGMII, 802.3z and RGMII modes.
> +	 * When in 802.3z mode, we must have AN enabled:
> +	 * "Bit 2 Field InBandAnEn In-band Auto-Negotiation enable. ...
> +	 * When <PortType> = 1 (1000BASE-X) this field must be set to 1."
> +	 */
> +	if (phy_interface_mode_is_8023z(state->interface)) {
> +		if (!phylink_test(state->advertising, Autoneg)) {
> +			bitmap_zero(supported, __ETHTOOL_LINK_MODE_MASK_NBITS);
> +			return;
> +		}
> +	} else if (state->interface != PHY_INTERFACE_MODE_NA &&
> +		   state->interface != PHY_INTERFACE_MODE_QSGMII &&
> +		   state->interface != PHY_INTERFACE_MODE_SGMII &&
> +		   !phy_interface_mode_is_rgmii(state->interface)) {
>  		bitmap_zero(supported, __ETHTOOL_LINK_MODE_MASK_NBITS);
>  		return;
>  	}

Acked-by: Marek Behún <kabel@kernel.org>