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

[MD Danish Anwar]

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 at 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);
 }
 
 /**
@@ -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
-- 
2.34.1