Re: [PATCH net-next v2 4/4] net: dsa: xrs700x: add HSR offloading support

[Vladimir Oltean <olteanv@gmail.com>]

On Thu, Feb 04, 2021 at 03:59:26PM -0600, George McCollister wrote:
> +static int xrs700x_hsr_join(struct dsa_switch *ds, int port,
> +			    struct net_device *hsr)
> +{
> +	unsigned int val = XRS_HSR_CFG_HSR_PRP;
> +	struct dsa_port *partner = NULL, *dp;
> +	struct xrs700x *priv = ds->priv;
> +	struct net_device *slave;
> +	enum hsr_version ver;
> +	int ret;
> +
> +	ret = hsr_get_version(hsr, &ver);
> +	if (ret)
> +		return ret;
> +
> +	if (ver == HSR_V1)
> +		val |= XRS_HSR_CFG_HSR;
> +	else if (ver == PRP_V1)
> +		val |= XRS_HSR_CFG_PRP;
> +	else
> +		return -EOPNOTSUPP;
> +
> +	dsa_hsr_foreach_port(dp, ds, hsr) {
> +		partner = dp;
> +	}
> +
> +	/* We can't enable redundancy on the switch until both
> +	 * redundant ports have signed up.
> +	 */
> +	if (!partner)
> +		return 0;
> +
> +	regmap_fields_write(priv->ps_forward, partner->index,
> +			    XRS_PORT_DISABLED);
> +	regmap_fields_write(priv->ps_forward, port, XRS_PORT_DISABLED);
> +
> +	regmap_write(priv->regmap, XRS_HSR_CFG(partner->index),
> +		     val | XRS_HSR_CFG_LANID_A);
> +	regmap_write(priv->regmap, XRS_HSR_CFG(port),
> +		     val | XRS_HSR_CFG_LANID_B);
> +
> +	/* Clear bits for both redundant ports (HSR only) and the CPU port to
> +	 * enable forwarding.
> +	 */
> +	val = GENMASK(ds->num_ports - 1, 0);
> +	if (ver == HSR_V1) {
> +		val &= ~BIT(partner->index);
> +		val &= ~BIT(port);
> +	}
> +	val &= ~BIT(dsa_upstream_port(ds, port));
> +	regmap_write(priv->regmap, XRS_PORT_FWD_MASK(partner->index), val);
> +	regmap_write(priv->regmap, XRS_PORT_FWD_MASK(port), val);
> +
> +	regmap_fields_write(priv->ps_forward, partner->index,
> +			    XRS_PORT_FORWARDING);
> +	regmap_fields_write(priv->ps_forward, port, XRS_PORT_FORWARDING);
> +
> +	slave = dsa_to_port(ds, port)->slave;
> +
> +	slave->features |= NETIF_F_HW_HSR_TAG_INS | NETIF_F_HW_HSR_TAG_RM |
> +			   NETIF_F_HW_HSR_FWD | NETIF_F_HW_HSR_DUP;
> +
> +	return 0;
> +}

Is it deliberate that only one slave HSR/PRP port will have the offload
ethtool features set? If yes, then I find that a bit odd from a user
point of view.