net: lan966x: Extend switchdev with fdb support

Extend lan966x driver with fdb support by implementing the switchdev
calls SWITCHDEV_FDB_ADD_TO_DEVICE and SWITCHDEV_FDB_DEL_TO_DEVICE.
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/microchip/lan966x/Makefile

@@ -7,4 +7,4 @@ obj-$(CONFIG_LAN966X_SWITCH) += lan966x-switch.o
 
 lan966x-switch-objs  := lan966x_main.o lan966x_phylink.o lan966x_port.o \
 			lan966x_mac.o lan966x_ethtool.o lan966x_switchdev.o \
-			lan966x_vlan.o
+			lan966x_vlan.o lan966x_fdb.o

drivers/net/ethernet/microchip/lan966x/lan966x_fdb.c

+// SPDX-License-Identifier: GPL-2.0+
+
+#include <net/switchdev.h>
+
+#include "lan966x_main.h"
+
+struct lan966x_fdb_event_work {
+	struct work_struct work;
+	struct switchdev_notifier_fdb_info fdb_info;
+	struct net_device *dev;
+	struct lan966x *lan966x;
+	unsigned long event;
+};
+
+struct lan966x_fdb_entry {
+	struct list_head list;
+	unsigned char mac[ETH_ALEN] __aligned(2);
+	u16 vid;
+	u32 references;
+};
+
+static struct lan966x_fdb_entry *
+lan966x_fdb_find_entry(struct lan966x *lan966x,
+		       struct switchdev_notifier_fdb_info *fdb_info)
+{
+	struct lan966x_fdb_entry *fdb_entry;
+
+	list_for_each_entry(fdb_entry, &lan966x->fdb_entries, list) {
+		if (fdb_entry->vid == fdb_info->vid &&
+		    ether_addr_equal(fdb_entry->mac, fdb_info->addr))
+			return fdb_entry;
+	}
+
+	return NULL;
+}
+
+static void lan966x_fdb_add_entry(struct lan966x *lan966x,
+				  struct switchdev_notifier_fdb_info *fdb_info)
+{
+	struct lan966x_fdb_entry *fdb_entry;
+
+	fdb_entry = lan966x_fdb_find_entry(lan966x, fdb_info);
+	if (fdb_entry) {
+		fdb_entry->references++;
+		return;
+	}
+
+	fdb_entry = kzalloc(sizeof(*fdb_entry), GFP_KERNEL);
+	if (!fdb_entry)
+		return;
+
+	ether_addr_copy(fdb_entry->mac, fdb_info->addr);
+	fdb_entry->vid = fdb_info->vid;
+	fdb_entry->references = 1;
+	list_add_tail(&fdb_entry->list, &lan966x->fdb_entries);
+}
+
+static bool lan966x_fdb_del_entry(struct lan966x *lan966x,
+				  struct switchdev_notifier_fdb_info *fdb_info)
+{
+	struct lan966x_fdb_entry *fdb_entry, *tmp;
+
+	list_for_each_entry_safe(fdb_entry, tmp, &lan966x->fdb_entries,
+				 list) {
+		if (fdb_entry->vid == fdb_info->vid &&
+		    ether_addr_equal(fdb_entry->mac, fdb_info->addr)) {
+			fdb_entry->references--;
+			if (!fdb_entry->references) {
+				list_del(&fdb_entry->list);
+				kfree(fdb_entry);
+				return true;
+			}
+			break;
+		}
+	}
+
+	return false;
+}
+
+void lan966x_fdb_write_entries(struct lan966x *lan966x, u16 vid)
+{
+	struct lan966x_fdb_entry *fdb_entry;
+
+	list_for_each_entry(fdb_entry, &lan966x->fdb_entries, list) {
+		if (fdb_entry->vid != vid)
+			continue;
+
+		lan966x_mac_cpu_learn(lan966x, fdb_entry->mac, fdb_entry->vid);
+	}
+}
+
+void lan966x_fdb_erase_entries(struct lan966x *lan966x, u16 vid)
+{
+	struct lan966x_fdb_entry *fdb_entry;
+
+	list_for_each_entry(fdb_entry, &lan966x->fdb_entries, list) {
+		if (fdb_entry->vid != vid)
+			continue;
+
+		lan966x_mac_cpu_forget(lan966x, fdb_entry->mac, fdb_entry->vid);
+	}
+}
+
+static void lan966x_fdb_purge_entries(struct lan966x *lan966x)
+{
+	struct lan966x_fdb_entry *fdb_entry, *tmp;
+
+	list_for_each_entry_safe(fdb_entry, tmp, &lan966x->fdb_entries, list) {
+		list_del(&fdb_entry->list);
+		kfree(fdb_entry);
+	}
+}
+
+int lan966x_fdb_init(struct lan966x *lan966x)
+{
+	INIT_LIST_HEAD(&lan966x->fdb_entries);
+	lan966x->fdb_work = alloc_ordered_workqueue("lan966x_order", 0);
+	if (!lan966x->fdb_work)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void lan966x_fdb_deinit(struct lan966x *lan966x)
+{
+	destroy_workqueue(lan966x->fdb_work);
+	lan966x_fdb_purge_entries(lan966x);
+}
+
+static void lan966x_fdb_event_work(struct work_struct *work)
+{
+	struct lan966x_fdb_event_work *fdb_work =
+		container_of(work, struct lan966x_fdb_event_work, work);
+	struct switchdev_notifier_fdb_info *fdb_info;
+	struct net_device *dev = fdb_work->dev;
+	struct lan966x_port *port;
+	struct lan966x *lan966x;
+	int ret;
+
+	fdb_info = &fdb_work->fdb_info;
+	lan966x = fdb_work->lan966x;
+
+	if (lan966x_netdevice_check(dev)) {
+		port = netdev_priv(dev);
+
+		switch (fdb_work->event) {
+		case SWITCHDEV_FDB_ADD_TO_DEVICE:
+			if (!fdb_info->added_by_user)
+				break;
+			lan966x_mac_add_entry(lan966x, port, fdb_info->addr,
+					      fdb_info->vid);
+			break;
+		case SWITCHDEV_FDB_DEL_TO_DEVICE:
+			if (!fdb_info->added_by_user)
+				break;
+			lan966x_mac_del_entry(lan966x, fdb_info->addr,
+					      fdb_info->vid);
+			break;
+		}
+	} else {
+		if (!netif_is_bridge_master(dev))
+			goto out;
+
+		/* In case the bridge is called */
+		switch (fdb_work->event) {
+		case SWITCHDEV_FDB_ADD_TO_DEVICE:
+			/* If there is no front port in this vlan, there is no
+			 * point to copy the frame to CPU because it would be
+			 * just dropped at later point. So add it only if
+			 * there is a port but it is required to store the fdb
+			 * entry for later point when a port actually gets in
+			 * the vlan.
+			 */
+			lan966x_fdb_add_entry(lan966x, fdb_info);
+			if (!lan966x_vlan_cpu_member_cpu_vlan_mask(lan966x,
+								   fdb_info->vid))
+				break;
+
+			lan966x_mac_cpu_learn(lan966x, fdb_info->addr,
+					      fdb_info->vid);
+			break;
+		case SWITCHDEV_FDB_DEL_TO_DEVICE:
+			ret = lan966x_fdb_del_entry(lan966x, fdb_info);
+			if (!lan966x_vlan_cpu_member_cpu_vlan_mask(lan966x,
+								   fdb_info->vid))
+				break;
+
+			if (ret)
+				lan966x_mac_cpu_forget(lan966x, fdb_info->addr,
+						       fdb_info->vid);
+			break;
+		}
+	}
+
+out:
+	kfree(fdb_work->fdb_info.addr);
+	kfree(fdb_work);
+	dev_put(dev);
+}
+
+int lan966x_handle_fdb(struct net_device *dev,
+		       struct net_device *orig_dev,
+		       unsigned long event, const void *ctx,
+		       const struct switchdev_notifier_fdb_info *fdb_info)
+{
+	struct lan966x_port *port = netdev_priv(dev);
+	struct lan966x *lan966x = port->lan966x;
+	struct lan966x_fdb_event_work *fdb_work;
+
+	if (ctx && ctx != port)
+		return 0;
+
+	switch (event) {
+	case SWITCHDEV_FDB_ADD_TO_DEVICE:
+	case SWITCHDEV_FDB_DEL_TO_DEVICE:
+		if (lan966x_netdevice_check(orig_dev) &&
+		    !fdb_info->added_by_user)
+			break;
+
+		fdb_work = kzalloc(sizeof(*fdb_work), GFP_ATOMIC);
+		if (!fdb_work)
+			return -ENOMEM;
+
+		fdb_work->dev = orig_dev;
+		fdb_work->lan966x = lan966x;
+		fdb_work->event = event;
+		INIT_WORK(&fdb_work->work, lan966x_fdb_event_work);
+		memcpy(&fdb_work->fdb_info, fdb_info, sizeof(fdb_work->fdb_info));
+		fdb_work->fdb_info.addr = kzalloc(ETH_ALEN, GFP_ATOMIC);
+		if (!fdb_work->fdb_info.addr)
+			goto err_addr_alloc;
+
+		ether_addr_copy((u8 *)fdb_work->fdb_info.addr, fdb_info->addr);
+		dev_hold(orig_dev);
+
+		queue_work(lan966x->fdb_work, &fdb_work->work);
+		break;
+	}
+
+	return 0;
+err_addr_alloc:
+	kfree(fdb_work);
+	return -ENOMEM;
+}

drivers/net/ethernet/microchip/lan966x/lan966x_main.c

@@ -919,6 +919,10 @@ static int lan966x_probe(struct platform_device *pdev)
 		lan966x_port_init(lan966x->ports[p]);
 	}
 
+	err = lan966x_fdb_init(lan966x);
+	if (err)
+		goto cleanup_ports;
+
 	return 0;
 
 cleanup_ports:
@@ -944,6 +948,7 @@ static int lan966x_remove(struct platform_device *pdev)
 	mutex_destroy(&lan966x->stats_lock);
 
 	lan966x_mac_purge_entries(lan966x);
+	lan966x_fdb_deinit(lan966x);
 
 	return 0;
 }

drivers/net/ethernet/microchip/lan966x/lan966x_main.h

@@ -8,6 +8,7 @@
 #include <linux/jiffies.h>
 #include <linux/phy.h>
 #include <linux/phylink.h>
+#include <net/switchdev.h>
 
 #include "lan966x_regs.h"
 #include "lan966x_ifh.h"
@@ -100,6 +101,10 @@ struct lan966x {
 	/* interrupts */
 	int xtr_irq;
 	int ana_irq;
+
+	/* worqueue for fdb */
+	struct workqueue_struct *fdb_work;
+	struct list_head fdb_entries;
 };
 
 struct lan966x_port_config {
@@ -190,6 +195,15 @@ void lan966x_vlan_port_del_vlan(struct lan966x_port *port, u16 vid);
 void lan966x_vlan_cpu_add_vlan(struct lan966x *lan966x, u16 vid);
 void lan966x_vlan_cpu_del_vlan(struct lan966x *lan966x, u16 vid);
 
+void lan966x_fdb_write_entries(struct lan966x *lan966x, u16 vid);
+void lan966x_fdb_erase_entries(struct lan966x *lan966x, u16 vid);
+int lan966x_fdb_init(struct lan966x *lan966x);
+void lan966x_fdb_deinit(struct lan966x *lan966x);
+int lan966x_handle_fdb(struct net_device *dev,
+		       struct net_device *orig_dev,
+		       unsigned long event, const void *ctx,
+		       const struct switchdev_notifier_fdb_info *fdb_info);
+
 static inline void __iomem *lan_addr(void __iomem *base[],
 				     int id, int tinst, int tcnt,
 				     int gbase, int ginst,

drivers/net/ethernet/microchip/lan966x/lan966x_switchdev.c

@@ -293,6 +293,19 @@ static int lan966x_netdevice_event(struct notifier_block *nb,
 	return notifier_from_errno(ret);
 }
 
+static bool lan966x_foreign_dev_check(const struct net_device *dev,
+				      const struct net_device *foreign_dev)
+{
+	struct lan966x_port *port = netdev_priv(dev);
+	struct lan966x *lan966x = port->lan966x;
+
+	if (netif_is_bridge_master(foreign_dev))
+		if (lan966x->bridge != foreign_dev)
+			return true;
+
+	return false;
+}
+
 static int lan966x_switchdev_event(struct notifier_block *nb,
 				   unsigned long event, void *ptr)
 {
@@ -305,6 +318,14 @@ static int lan966x_switchdev_event(struct notifier_block *nb,
 						     lan966x_netdevice_check,
 						     lan966x_port_attr_set);
 		return notifier_from_errno(err);
+	case SWITCHDEV_FDB_ADD_TO_DEVICE:
+	case SWITCHDEV_FDB_DEL_TO_DEVICE:
+		err = switchdev_handle_fdb_event_to_device(dev, event, ptr,
+							   lan966x_netdevice_check,
+							   lan966x_foreign_dev_check,
+							   lan966x_handle_fdb,
+							   NULL);
+		return notifier_from_errno(err);
 	}
 
 	return NOTIFY_DONE;

drivers/net/ethernet/microchip/lan966x/lan966x_vlan.c

@@ -211,8 +211,15 @@ void lan966x_vlan_port_add_vlan(struct lan966x_port *port,
 {
 	struct lan966x *lan966x = port->lan966x;
 
-	if (lan966x_vlan_cpu_member_cpu_vlan_mask(lan966x, vid))
+	/* If the CPU(br) is already part of the vlan then add the fdb
+	 * entries in MAC table to copy the frames to the CPU(br).
+	 * If the CPU(br) is not part of the vlan then it would
+	 * just drop the frames.
+	 */
+	if (lan966x_vlan_cpu_member_cpu_vlan_mask(lan966x, vid)) {
 		lan966x_vlan_cpu_add_vlan_mask(lan966x, vid);
+		lan966x_fdb_write_entries(lan966x, vid);
+	}
 
 	lan966x_vlan_port_set_vid(port, vid, pvid, untagged);
 	lan966x_vlan_port_add_vlan_mask(port, vid);
@@ -231,8 +238,10 @@ void lan966x_vlan_port_del_vlan(struct lan966x_port *port, u16 vid)
 	 * that vlan but still keep it in the mask because it may be needed
 	 * again then another port gets added in that vlan
 	 */
-	if (!lan966x_vlan_port_any_vlan_mask(lan966x, vid))
+	if (!lan966x_vlan_port_any_vlan_mask(lan966x, vid)) {
 		lan966x_vlan_cpu_del_vlan_mask(lan966x, vid);
+		lan966x_fdb_erase_entries(lan966x, vid);
+	}
 }
 
 void lan966x_vlan_cpu_add_vlan(struct lan966x *lan966x, u16 vid)
@@ -249,6 +258,7 @@ void lan966x_vlan_cpu_add_vlan(struct lan966x *lan966x, u16 vid)
 		lan966x_vlan_cpu_add_vlan_mask(lan966x, vid);
 
 	lan966x_vlan_cpu_add_cpu_vlan_mask(lan966x, vid);
+	lan966x_fdb_write_entries(lan966x, vid);
 }
 
 void lan966x_vlan_cpu_del_vlan(struct lan966x *lan966x, u16 vid)
@@ -256,6 +266,7 @@ void lan966x_vlan_cpu_del_vlan(struct lan966x *lan966x, u16 vid)
 	/* Remove the CPU part of the vlan */
 	lan966x_vlan_cpu_del_cpu_vlan_mask(lan966x, vid);
 	lan966x_vlan_cpu_del_vlan_mask(lan966x, vid);
+	lan966x_fdb_erase_entries(lan966x, vid);
 }
 
 void lan966x_vlan_init(struct lan966x *lan966x)