[net-next v13 08/11] net: mtip: Extend the L2 switch driver for imx287 with bridge operations

[Lukasz Majewski]

After this change the MTIP L2 switch can be configured as offloading
device for packet switching when bridge on their interfaces is created.

Signed-off-by: Lukasz Majewski <lukma@xxxxxxx>
---

Changes for v13:
- New patch - created by excluding some code from large (i.e. v12 and
  earlier) MTIP driver
---
 .../net/ethernet/freescale/mtipsw/Makefile    |   2 +-
 .../net/ethernet/freescale/mtipsw/mtipl2sw.c  |   6 +
 .../net/ethernet/freescale/mtipsw/mtipl2sw.h  |   2 +
 .../ethernet/freescale/mtipsw/mtipl2sw_br.c   | 120 ++++++++++++++++++
 4 files changed, 129 insertions(+), 1 deletion(-)
 create mode 100644 drivers/net/ethernet/freescale/mtipsw/mtipl2sw_br.c

diff --git a/drivers/net/ethernet/freescale/mtipsw/Makefile b/drivers/net/ethernet/freescale/mtipsw/Makefile
index a99aaf6ddfb2..81e2b0e03e6c 100644
--- a/drivers/net/ethernet/freescale/mtipsw/Makefile
+++ b/drivers/net/ethernet/freescale/mtipsw/Makefile
@@ -1,4 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
 
 obj-$(CONFIG_FEC_MTIP_L2SW) += nxp-mtipl2sw.o
-nxp-mtipl2sw-objs := mtipl2sw.o mtipl2sw_mgnt.o
+nxp-mtipl2sw-objs := mtipl2sw.o mtipl2sw_mgnt.o mtipl2sw_br.o
diff --git a/drivers/net/ethernet/freescale/mtipsw/mtipl2sw.c b/drivers/net/ethernet/freescale/mtipsw/mtipl2sw.c
index 36700951cc97..95a2b874fd9c 100644
--- a/drivers/net/ethernet/freescale/mtipsw/mtipl2sw.c
+++ b/drivers/net/ethernet/freescale/mtipsw/mtipl2sw.c
@@ -1918,6 +1918,10 @@ static int mtip_sw_probe(struct platform_device *pdev)
 	if (ret)
 		return dev_err_probe(&pdev->dev, ret, "Could not alloc IRQ\n");
 
+	ret = mtip_register_notifiers(fep);
+	if (ret)
+		return ret;
+
 	ret = mtip_ndev_init(fep, pdev);
 	if (ret) {
 		dev_err(&pdev->dev, "%s: Failed to create virtual ndev (%d)\n",
@@ -1959,6 +1963,7 @@ static int mtip_sw_probe(struct platform_device *pdev)
  dma_init_err:
 	mtip_ndev_cleanup(fep);
  ndev_init_err:
+	mtip_unregister_notifiers(fep);
 
 	return ret;
 }
@@ -1967,6 +1972,7 @@ static void mtip_sw_remove(struct platform_device *pdev)
 {
 	struct switch_enet_private *fep = platform_get_drvdata(pdev);
 
+	mtip_unregister_notifiers(fep);
 	mtip_ndev_cleanup(fep);
 
 	mtip_mii_remove(fep);
diff --git a/drivers/net/ethernet/freescale/mtipsw/mtipl2sw.h b/drivers/net/ethernet/freescale/mtipsw/mtipl2sw.h
index 458c06f5be68..e85034df7031 100644
--- a/drivers/net/ethernet/freescale/mtipsw/mtipl2sw.h
+++ b/drivers/net/ethernet/freescale/mtipsw/mtipl2sw.h
@@ -647,6 +647,8 @@ int mtip_port_learning_config(struct switch_enet_private *fep, int port,
 int mtip_port_blocking_config(struct switch_enet_private *fep, int port,
 			      bool enable);
 bool mtip_is_switch_netdev_port(const struct net_device *ndev);
+int mtip_register_notifiers(struct switch_enet_private *fep);
+void mtip_unregister_notifiers(struct switch_enet_private *fep);
 int mtip_port_enable_config(struct switch_enet_private *fep, int port,
 			    bool tx_en, bool rx_en);
 void mtip_clear_atable(struct switch_enet_private *fep);
diff --git a/drivers/net/ethernet/freescale/mtipsw/mtipl2sw_br.c b/drivers/net/ethernet/freescale/mtipsw/mtipl2sw_br.c
new file mode 100644
index 000000000000..edfd95a7790d
--- /dev/null
+++ b/drivers/net/ethernet/freescale/mtipsw/mtipl2sw_br.c
@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  L2 switch Controller driver for MTIP block - bridge network interface
+ *
+ *  Copyright (C) 2025 DENX Software Engineering GmbH
+ *  Lukasz Majewski <lukma@xxxxxxx>
+ */
+
+#include <linux/etherdevice.h>
+#include <linux/netdevice.h>
+#include <linux/platform_device.h>
+
+#include "mtipl2sw.h"
+
+static int mtip_ndev_port_link(struct net_device *ndev,
+			       struct net_device *br_ndev,
+			       struct netlink_ext_ack *extack)
+{
+	struct mtip_ndev_priv *priv = netdev_priv(ndev), *other_priv;
+	struct switch_enet_private *fep = priv->fep;
+	struct net_device *other_ndev;
+
+	/* Check if one port of MTIP switch is already bridged */
+	if (fep->br_members && !fep->br_offload) {
+		/* Get the second bridge ndev */
+		other_ndev = fep->ndev[fep->br_members - 1];
+		other_priv = netdev_priv(other_ndev);
+		if (other_priv->master_dev != br_ndev) {
+			NL_SET_ERR_MSG_MOD(extack,
+					   "L2 offloading only possible for the same bridge!");
+			return notifier_from_errno(-EOPNOTSUPP);
+		}
+
+		fep->br_offload = 1;
+		mtip_switch_dis_port_separation(fep);
+		mtip_clear_atable(fep);
+	}
+
+	if (!priv->master_dev)
+		priv->master_dev = br_ndev;
+
+	fep->br_members |= BIT(priv->portnum - 1);
+
+	dev_dbg(&ndev->dev,
+		"%s: ndev: %s br: %s fep: %p members: 0x%x offload: %d\n",
+		__func__, ndev->name,  br_ndev->name, fep, fep->br_members,
+		fep->br_offload);
+
+	return NOTIFY_DONE;
+}
+
+static void mtip_netdevice_port_unlink(struct net_device *ndev)
+{
+	struct mtip_ndev_priv *priv = netdev_priv(ndev);
+	struct switch_enet_private *fep = priv->fep;
+
+	dev_dbg(&ndev->dev, "%s: ndev: %s members: 0x%x\n", __func__,
+		ndev->name, fep->br_members);
+
+	fep->br_members &= ~BIT(priv->portnum - 1);
+	priv->master_dev = NULL;
+
+	if (fep->br_members && fep->br_offload) {
+		fep->br_offload = 0;
+		mtip_switch_en_port_separation(fep);
+		mtip_clear_atable(fep);
+	}
+}
+
+/* netdev notifier */
+static int mtip_netdevice_event(struct notifier_block *unused,
+				unsigned long event, void *ptr)
+{
+	struct net_device *ndev = netdev_notifier_info_to_dev(ptr);
+	struct netdev_notifier_changeupper_info *info = ptr;
+	struct netlink_ext_ack *extack;
+	int ret = NOTIFY_DONE;
+
+	if (!mtip_is_switch_netdev_port(ndev))
+		return NOTIFY_DONE;
+
+	extack = netdev_notifier_info_to_extack(&info->info);
+
+	switch (event) {
+	case NETDEV_CHANGEUPPER:
+		if (!netif_is_bridge_master(info->upper_dev))
+			break;
+
+		if (info->linking)
+			ret = mtip_ndev_port_link(ndev, info->upper_dev,
+						  extack);
+		else
+			mtip_netdevice_port_unlink(ndev);
+
+		break;
+	default:
+		return NOTIFY_DONE;
+	}
+
+	return notifier_from_errno(ret);
+}
+
+static struct notifier_block mtip_netdevice_nb __read_mostly = {
+	.notifier_call = mtip_netdevice_event,
+};
+
+int mtip_register_notifiers(struct switch_enet_private *fep)
+{
+	int ret = register_netdevice_notifier(&mtip_netdevice_nb);
+
+	if (ret)
+		dev_err(&fep->pdev->dev, "can't register netdevice notifier\n");
+
+	return ret;
+}
+
+void mtip_unregister_notifiers(struct switch_enet_private *fep)
+{
+	unregister_netdevice_notifier(&mtip_netdevice_nb);
+}
-- 
2.39.5