Re: [PATCH net-next v2] net: ti: icssg-prueth: Add multicast filtering support

[Wojciech Drewek <wojciech.drewek@intel.com>]

On 04.06.2024 13:44, MD Danish Anwar wrote:
> Add multicast filtering support for ICSSG Driver.
> 
> The driver will keep a copy of multicast addresses in emac->mcast_list.
> This list will be kept in sync with the netdev list and to add / del
> multicast address icssg_prueth_mac_add_mcast / icssg_prueth_mac_del_mcast
> APIs will be called.
> 
> To add a mac_address for a port, driver need to call icssg_fdb_add_del()
> and pass the mac_address and BIT(port_id) to the API. The ICSSG firmware
> will then configure the rules and allow filtering.
> 
> If a mac_address is added to port0 and the same mac_address needs to be
> added for port1, driver needs to pass BIT(port0) | BIT(port1) to the
> icssg_fdb_add_del() API. If driver just pass BIT(port1) then the entry for
> port0 will be overwritten / lost. This is a design constraint on the
> firmware side.
> 
> To overcome this in the driver, to add any mac_address for let's say portX
> driver first checks if the same mac_address is already added for any other
> port. If yes driver calls icssg_fdb_add_del() with BIT(portX) |
> BIT(other_existing_port). If not, driver calls icssg_fdb_add_del() with
> BIT(portX).
> 
> The same thing is applicable for deleting mac_addresses as well. This
> logic is in icssg_prueth_mac_add_mcast / icssg_prueth_mac_del_mcast APIs.
> 
> Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
> ---
> v1 -> v2:
> *) Rebased on latest net-next/main.
> 
> NOTE: This series can be applied cleanly on the tip of net-next/main. This
> series doesn't depend on any other ICSSG driver related series that is
> floating around in netdev.
> 
> v1 https://lore.kernel.org/all/20240516091752.2969092-1-danishanwar@ti.com/
> 
>  drivers/net/ethernet/ti/icssg/icssg_prueth.c | 50 ++++++++++++++++++--
>  drivers/net/ethernet/ti/icssg/icssg_prueth.h |  3 ++
>  2 files changed, 49 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/ti/icssg/icssg_prueth.c b/drivers/net/ethernet/ti/icssg/icssg_prueth.c
> index 6e65aa0977d4..03dd49f0afb7 100644
> --- a/drivers/net/ethernet/ti/icssg/icssg_prueth.c
> +++ b/drivers/net/ethernet/ti/icssg/icssg_prueth.c
> @@ -439,6 +439,37 @@ const struct icss_iep_clockops prueth_iep_clockops = {
>  	.perout_enable = prueth_perout_enable,
>  };
>  
> +static int icssg_prueth_mac_add_mcast(struct net_device *ndev, const u8 *addr)
> +{
> +	struct prueth_emac *emac = netdev_priv(ndev);
> +	int port_mask = BIT(emac->port_id);
> +
> +	port_mask |= icssg_fdb_lookup(emac, addr, 0);
> +	icssg_fdb_add_del(emac, addr, 0, port_mask, true);
> +	icssg_vtbl_modify(emac, 0, port_mask, port_mask, true);
> +
> +	return 0;
> +}
> +
> +static int icssg_prueth_mac_del_mcast(struct net_device *ndev, const u8 *addr)
> +{
> +	struct prueth_emac *emac = netdev_priv(ndev);
> +	int port_mask = BIT(emac->port_id);
> +	int other_port_mask;
> +
> +	other_port_mask = port_mask ^ icssg_fdb_lookup(emac, addr, 0);
> +
> +	icssg_fdb_add_del(emac, addr, 0, port_mask, false);
> +	icssg_vtbl_modify(emac, 0, port_mask, port_mask, false);
> +
> +	if (other_port_mask) {
> +		icssg_fdb_add_del(emac, addr, 0, other_port_mask, true);
> +		icssg_vtbl_modify(emac, 0, other_port_mask, other_port_mask, true);
> +	}
> +
> +	return 0;
> +}
> +
>  /**
>   * emac_ndo_open - EMAC device open
>   * @ndev: network adapter device
> @@ -547,6 +578,8 @@ static int emac_ndo_open(struct net_device *ndev)
>  
>  	prueth->emacs_initialized++;
>  
> +	__hw_addr_init(&emac->mcast_list);
> +
>  	queue_work(system_long_wq, &emac->stats_work.work);
>  
>  	return 0;
> @@ -599,6 +632,9 @@ static int emac_ndo_stop(struct net_device *ndev)
>  
>  	icssg_class_disable(prueth->miig_rt, prueth_emac_slice(emac));
>  
> +	__dev_mc_unsync(ndev, icssg_prueth_mac_del_mcast);
> +	__hw_addr_init(&emac->mcast_list);
> +
>  	atomic_set(&emac->tdown_cnt, emac->tx_ch_num);
>  	/* ensure new tdown_cnt value is visible */
>  	smp_mb__after_atomic();
> @@ -675,10 +711,15 @@ static void emac_ndo_set_rx_mode_work(struct work_struct *work)
>  		return;
>  	}
>  
> -	if (!netdev_mc_empty(ndev)) {
> -		emac_set_port_state(emac, ICSSG_EMAC_PORT_MC_FLOODING_ENABLE);
> -		return;
> -	}
> +	/* make a mc list copy */
> +
> +	netif_addr_lock_bh(ndev);
> +	__hw_addr_sync(&emac->mcast_list, &ndev->mc, ndev->addr_len);
> +	netif_addr_unlock_bh(ndev);
> +
> +	__hw_addr_sync_dev(&emac->mcast_list, ndev,
> +			   icssg_prueth_mac_add_mcast,
> +			   icssg_prueth_mac_del_mcast);

Is there a reason __dev_mc_sync can't be used here?
net_device has mc list already, no need to keep your own list
in prueth_emac.

>  }
>  
>  /**
> @@ -767,6 +808,7 @@ static int prueth_netdev_init(struct prueth *prueth,
>  	SET_NETDEV_DEV(ndev, prueth->dev);
>  	spin_lock_init(&emac->lock);
>  	mutex_init(&emac->cmd_lock);
> +	__hw_addr_init(&emac->mcast_list);
>  
>  	emac->phy_node = of_parse_phandle(eth_node, "phy-handle", 0);
>  	if (!emac->phy_node && !of_phy_is_fixed_link(eth_node)) {
> diff --git a/drivers/net/ethernet/ti/icssg/icssg_prueth.h b/drivers/net/ethernet/ti/icssg/icssg_prueth.h
> index 5eeeccb73665..2bfda26b5901 100644
> --- a/drivers/net/ethernet/ti/icssg/icssg_prueth.h
> +++ b/drivers/net/ethernet/ti/icssg/icssg_prueth.h
> @@ -155,6 +155,9 @@ struct prueth_emac {
>  	unsigned int tx_ts_enabled : 1;
>  	unsigned int half_duplex : 1;
>  
> +	/* List for storing multicast addresses */
> +	struct netdev_hw_addr_list mcast_list;
> +
>  	/* DMA related */
>  	struct prueth_tx_chn tx_chns[PRUETH_MAX_TX_QUEUES];
>  	struct completion tdown_complete;
> 
> base-commit: 2589d668e1a6ebe85329f1054cdad13647deac06