Re: [PATCH iwl-next v5 5/9] igc: Add support for frame preemption verification

[Vladimir Oltean <vladimir.oltean@nxp.com>]

On Wed, Feb 19, 2025 at 09:53:45PM -0500, Faizal Rahim wrote:
> @@ -3956,6 +3970,30 @@ static int igc_uc_unsync(struct net_device *netdev, const unsigned char *addr)
>  	return 0;
>  }
>  
> +/**
> + * igc_enable_empty_addr_recv - Enable rx of packets with all-zeroes MAC address
> + * @adapter: Pointer to the igc_adapter structure.
> + *
> + * Frame preemption verification requires that packets with the all-zeroes
> + * MAC address are allowed to be received by IGC. This function adds the
> + * all-zeroes destination address to the list of acceptable addresses.
> + *
> + * Return: 0 on success, negative value otherwise.
> + */
> +int igc_enable_empty_addr_recv(struct igc_adapter *adapter)
> +{
> +	u8 empty[ETH_ALEN] = { };
> +
> +	return igc_add_mac_filter(adapter, IGC_MAC_FILTER_TYPE_DST, empty, -1);
> +}
> +
> +void igc_disable_empty_addr_recv(struct igc_adapter *adapter)
> +{
> +	u8 empty[ETH_ALEN] = { };
> +
> +	igc_del_mac_filter(adapter, IGC_MAC_FILTER_TYPE_DST, empty);
> +}
> +
>  /**
>   * igc_set_rx_mode - Secondary Unicast, Multicast and Promiscuous mode set
>   * @netdev: network interface device structure
> @@ -434,6 +569,11 @@ int igc_tsn_reset(struct igc_adapter *adapter)
>  	unsigned int new_flags;
>  	int err = 0;
>  
> +	if (adapter->fpe.mmsv.pmac_enabled)
> +		igc_enable_empty_addr_recv(adapter);
> +	else
> +		igc_disable_empty_addr_recv(adapter);
> +
>  	new_flags = igc_tsn_new_flags(adapter);
>  
>  	if (!(new_flags & IGC_FLAG_TSN_ANY_ENABLED))

Please monitor failures to add this MAC address filter somehow, don't
let errors be silent. If it returns -ENOSPC, you won't be able to
receive verification frames, but you'll never know it from the logs
(assuming the netdev_dbg() on the igc_add_mac_filter() success path
doesn't get printed anyway).