Re: [PATCH 5/9] ax88179_178a: Add support for ethtool pause parameter configuration

[Maxime Chevallier <maxime.chevallier@bootlin.com>]

Hi

On 7/1/26 07:42, Birger Koblitz wrote:
> The AX179A-based chips support pause parameter configuration.
> Make it available through ethtool ops.
> 
> Signed-off-by: Birger Koblitz <mail@birger-koblitz.de>
> ---
>  drivers/net/usb/ax88179_178a.c | 67 ++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 67 insertions(+)
> 
> diff --git a/drivers/net/usb/ax88179_178a.c b/drivers/net/usb/ax88179_178a.c
> index 16528d873e804fde5dcc27659048882eee1c3eaa..586c049c6f7422a853aeae5e9372ead3a6d106c5 100644
> --- a/drivers/net/usb/ax88179_178a.c
> +++ b/drivers/net/usb/ax88179_178a.c
> @@ -956,6 +956,71 @@ static int ax88179_set_link_ksettings(struct net_device *net,
>  	return mii_ethtool_set_link_ksettings(&dev->mii, cmd);
>  }
>  
> +static void ax88179a_get_pauseparam(struct net_device *net, struct ethtool_pauseparam *pause)
> +{
> +	struct usbnet *dev = netdev_priv(net);
> +	struct ax88179_data *data;
> +	u16 bmcr, lcladv, rmtadv;
> +	u8 cap;
> +
> +	data = dev->driver_priv;
> +
> +	if (data->chip_version < AX_VERSION_AX88179A)
> +		return;
> +
> +	bmcr = ax88179_mdio_read(net, dev->mii.phy_id, MII_BMCR);
> +	lcladv = ax88179_mdio_read(net, dev->mii.phy_id, MII_ADVERTISE);
> +	rmtadv = ax88179_mdio_read(net, dev->mii.phy_id, MII_LPA);
> +
> +	if (!(bmcr & BMCR_ANENABLE)) {
> +		pause->autoneg = 0;
> +		pause->rx_pause = 0;
> +		pause->tx_pause = 0;
> +		return;
> +	}
> +
> +	pause->autoneg = 1;

pause autoneg is not the same as link-wide autoneg. If link autoneg is disabled,
you have to keep track on how pause autoneg was configured by user, so that this
can be re-applied when link aneg gets re-enabled.

The best way to have this correct is to use phylink, but for that you'd need to
have a proper PHY driver instead of using the mii_ API here.

> +
> +	cap = mii_resolve_flowctrl_fdx(lcladv, rmtadv);
> +
> +	if (cap & FLOW_CTRL_RX)
> +		pause->rx_pause = 1;
> +
> +	if (cap & FLOW_CTRL_TX)
> +		pause->tx_pause = 1;
> +}
> +
> +static int ax88179a_set_pauseparam(struct net_device *net, struct ethtool_pauseparam *pause)
> +{
> +	struct usbnet *dev = netdev_priv(net);
> +	struct ax88179_data *data;
> +	u16 old, new1, bmcr;
> +	u8 cap = 0;
> +
> +	data = dev->driver_priv;
> +
> +	if (data->chip_version < AX_VERSION_AX88179A)
> +		return -EOPNOTSUPP;
> +
> +	bmcr = ax88179_mdio_read(net, dev->mii.phy_id, MII_BMCR);
> +	if (pause->autoneg && !(bmcr & BMCR_ANENABLE))
> +		return -EINVAL;

As I said, pause autoneg can be on while linke autoneg is off. of course, the
device doesn't advertise pause, but the driver needs to keep track of what's
the pause aneg flag.

Maxime