This commit adds hardware offloading for L2 switching on R-Car S4

Signed-off-by: Michael Dege <michael.dege@renesas.com>
Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
---
 drivers/net/ethernet/renesas/Makefile       |   2 +-
 drivers/net/ethernet/renesas/rswitch.h      |  42 +++-
 drivers/net/ethernet/renesas/rswitch_l2.c   | 318 ++++++++++++++++++++++++++++
 drivers/net/ethernet/renesas/rswitch_l2.h   |  15 ++
 drivers/net/ethernet/renesas/rswitch_main.c |  88 +++++++-
 5 files changed, 458 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/renesas/Makefile b/drivers/net/ethernet/renesas/Makefile
index 6222298bb5582b7091cf8de76acb83ac7dd39c11..d63e0c61bb68a9993d388967aea9e1d50f6a95be 100644
--- a/drivers/net/ethernet/renesas/Makefile
+++ b/drivers/net/ethernet/renesas/Makefile
@@ -8,7 +8,7 @@ obj-$(CONFIG_SH_ETH) += sh_eth.o
 ravb-objs := ravb_main.o ravb_ptp.o
 obj-$(CONFIG_RAVB) += ravb.o
 
-rswitch-objs := rswitch_main.o
+rswitch-objs := rswitch_main.o rswitch_l2.o
 obj-$(CONFIG_RENESAS_ETHER_SWITCH) += rswitch.o
 
 obj-$(CONFIG_RENESAS_GEN4_PTP) += rcar_gen4_ptp.o
diff --git a/drivers/net/ethernet/renesas/rswitch.h b/drivers/net/ethernet/renesas/rswitch.h
index 532192cbca4b520e06a7e35653929d8364f1ccb2..45a9d02c5b5d3e7b62554bd56c6c0cb9231f684c 100644
--- a/drivers/net/ethernet/renesas/rswitch.h
+++ b/drivers/net/ethernet/renesas/rswitch.h
@@ -1,19 +1,25 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 /* Renesas Ethernet Switch device driver
  *
- * Copyright (C) 2022 Renesas Electronics Corporation
+ * Copyright (C) 2022-2025 Renesas Electronics Corporation
  */
 
 #ifndef __RSWITCH_H__
 #define __RSWITCH_H__
 
 #include <linux/platform_device.h>
+#include <linux/phy.h>
+
 #include "rcar_gen4_ptp.h"
 
 #define RSWITCH_MAX_NUM_QUEUES	128
 
 #define RSWITCH_NUM_AGENTS	5
 #define RSWITCH_NUM_PORTS	3
+
+#define rswitch_for_all_ports(_priv, _rdev)			\
+	list_for_each_entry(_rdev, &_priv->port_list, list)
+
 #define rswitch_for_each_enabled_port(priv, i)		\
 	for (i = 0; i < RSWITCH_NUM_PORTS; i++)		\
 		if (priv->rdev[i]->disabled)		\
@@ -809,7 +815,8 @@ enum rswitch_gwca_mode {
 #define FWPC0_IP4EA		BIT(10)
 #define FWPC0_IPDSA		BIT(12)
 #define FWPC0_IPHLA		BIT(18)
-#define FWPC0_MACSDA		BIT(20)
+#define FWPC0_MACDSA		BIT(20)
+#define FWPC0_MACSSA		BIT(23)
 #define FWPC0_MACHLA		BIT(26)
 #define FWPC0_MACHMA		BIT(27)
 #define FWPC0_VLANSA		BIT(28)
@@ -821,11 +828,28 @@ enum rswitch_gwca_mode {
 #define FWPC2(i)		(FWPC20 + (i) * 0x10)
 #define FWCP2_LTWFW		GENMASK(16 + (RSWITCH_NUM_AGENTS - 1), 16)
 
+#define FWCP2_LTWFW_MASK	GENMASK(16 + (RSWITCH_NUM_AGENTS - 1), 16)
 #define FWPBFC(i)		(FWPBFC0 + (i) * 0x10)
 #define FWPBFC_PBDV		GENMASK(RSWITCH_NUM_AGENTS - 1, 0)
 
 #define FWPBFCSDC(j, i)         (FWPBFCSDC00 + (i) * 0x10 + (j) * 0x04)
 
+#define FWMACHEC_MACHMUE_MASK	GENMASK(26, 16)
+
+#define FWMACTIM_MACTIOG	BIT(0)
+#define FWMACTIM_MACTR		BIT(1)
+
+#define FWMACAGUSPC_MACAGUSP	GENMASK(9, 0)
+#define FWMACAGC_MACAGT		GENMASK(15, 0)
+#define FWMACAGC_MACAGE		BIT(16)
+#define FWMACAGC_MACAGSL	BIT(17)
+#define FWMACAGC_MACAGPM	BIT(18)
+#define FWMACAGC_MACDES		BIT(24)
+#define FWMACAGC_MACAGOG	BIT(28)
+#define FWMACAGC_MACDESOG	BIT(29)
+
+#define RSW_AGEING_TIME		300
+
 /* TOP */
 #define TPEMIMC7(queue)		(TPEMIMC70 + (queue) * 4)
 
@@ -994,10 +1018,18 @@ struct rswitch_device {
 	DECLARE_BITMAP(ts_skb_used, TS_TAGS_PER_PORT);
 	bool disabled;
 
+	struct list_head list;
+
 	int port;
 	struct rswitch_etha *etha;
 	struct device_node *np_port;
 	struct phy *serdes;
+
+	struct net_device *brdev;	/* master bridge device */
+	unsigned int learning_requested : 1;
+	unsigned int learning_offloaded : 1;
+	unsigned int forwarding_requested : 1;
+	unsigned int forwarding_offloaded : 1;
 };
 
 struct rswitch_mfwd_mac_table_entry {
@@ -1022,11 +1054,17 @@ struct rswitch_private {
 	struct rswitch_etha etha[RSWITCH_NUM_PORTS];
 	struct rswitch_mfwd mfwd;
 
+	struct list_head port_list;
+
 	spinlock_t lock;	/* lock interrupt registers' control */
 	struct clk *clk;
 
 	bool etha_no_runtime_change;
 	bool gwca_halt;
+	struct net_device *offload_brdev;
 };
 
+bool is_rdev(const struct net_device *ndev);
+void rswitch_modify(void __iomem *addr, enum rswitch_reg reg, u32 clear, u32 set);
+
 #endif	/* #ifndef __RSWITCH_H__ */
diff --git a/drivers/net/ethernet/renesas/rswitch_l2.c b/drivers/net/ethernet/renesas/rswitch_l2.c
new file mode 100644
index 0000000000000000000000000000000000000000..242beb1f15c089585f5fe5019f626df8824b971a
--- /dev/null
+++ b/drivers/net/ethernet/renesas/rswitch_l2.c
@@ -0,0 +1,318 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Renesas Ethernet Switch device driver
+ *
+ * Copyright (C) 2025 Renesas Electronics Corporation
+ */
+
+#include <linux/err.h>
+#include <linux/etherdevice.h>
+#include <linux/if_bridge.h>
+#include <linux/kernel.h>
+#include <net/switchdev.h>
+
+#include "rswitch.h"
+#include "rswitch_l2.h"
+
+static bool rdev_for_l2_offload(struct rswitch_device *rdev)
+{
+	return rdev->priv->offload_brdev &&
+	       rdev->brdev == rdev->priv->offload_brdev &&
+	       (test_bit(rdev->port, rdev->priv->opened_ports));
+}
+
+void rswitch_update_l2_offload(struct rswitch_private *priv)
+{
+	bool learning_needed, forwarding_needed;
+	unsigned int all_ports_mask, fwd_mask;
+	struct rswitch_device *rdev;
+
+	/* calculate fwd_mask with zeroes in bits corresponding to ports that
+	 * shall participate in hardware forwarding
+	 */
+	all_ports_mask = GENMASK(RSWITCH_NUM_AGENTS - 1, 0);
+	fwd_mask = all_ports_mask;
+
+	rswitch_for_all_ports(priv, rdev) {
+		if (rdev_for_l2_offload(rdev) && rdev->forwarding_requested)
+			fwd_mask &= ~BIT(rdev->port);
+	}
+
+	rswitch_for_all_ports(priv, rdev) {
+		if (rdev_for_l2_offload(rdev)) {
+			learning_needed = rdev->learning_requested;
+			forwarding_needed = rdev->forwarding_requested;
+		} else {
+			learning_needed = false;
+			forwarding_needed = false;
+		}
+
+		if (!rdev->learning_offloaded && learning_needed) {
+			rswitch_modify(priv->addr, FWPC0(rdev->port),
+				       0,
+				       FWPC0_MACSSA | FWPC0_MACHLA | FWPC0_MACHMA);
+
+			rdev->learning_offloaded = true;
+			netdev_info(rdev->ndev, "starting hw learning\n");
+		}
+
+		if (rdev->learning_offloaded && !learning_needed) {
+			rswitch_modify(priv->addr, FWPC0(rdev->port),
+				       FWPC0_MACSSA | FWPC0_MACHLA | FWPC0_MACHMA,
+				       0);
+
+			rdev->learning_offloaded = false;
+			netdev_info(rdev->ndev, "stopping hw learning\n");
+		}
+
+		if (forwarding_needed) {
+			/* Update allowed offload destinations even for ports
+			 * with L2 offload enabled earlier.
+			 *
+			 * Do not allow L2 forwarding to self for hw port.
+			 */
+			iowrite32(FIELD_PREP(FWCP2_LTWFW_MASK, fwd_mask | BIT(rdev->port)),
+				  priv->addr + FWPC2(rdev->port));
+
+			if (!rdev->forwarding_offloaded) {
+				rswitch_modify(priv->addr, FWPC0(rdev->port),
+					       0,
+					       FWPC0_MACDSA);
+
+				rdev->forwarding_offloaded = true;
+				netdev_info(rdev->ndev,
+					    "starting hw forwarding\n");
+			}
+		} else if (rdev->forwarding_offloaded) {
+			iowrite32(FIELD_PREP(FWCP2_LTWFW_MASK, fwd_mask | BIT(rdev->port)),
+				  priv->addr + FWPC2(rdev->port));
+
+			rswitch_modify(priv->addr, FWPC0(rdev->port),
+				       FWPC0_MACDSA,
+				       0);
+
+			rdev->forwarding_offloaded = false;
+			netdev_info(rdev->ndev, "stopping hw forwarding\n");
+		}
+	}
+}
+
+static void rswitch_update_offload_brdev(struct rswitch_private *priv,
+					 bool force_update_l2_offload)
+{
+	struct net_device *offload_brdev = NULL;
+	struct rswitch_device *rdev, *rdev2;
+
+	rswitch_for_all_ports(priv, rdev) {
+		if (!rdev->brdev)
+			continue;
+		rswitch_for_all_ports(priv, rdev2) {
+			if (rdev2 == rdev)
+				break;
+			if (rdev2->brdev == rdev->brdev) {
+				offload_brdev = rdev->brdev;
+				break;
+			}
+		}
+		if (offload_brdev)
+			break;
+	}
+
+	if (offload_brdev == priv->offload_brdev) {
+		if (offload_brdev && force_update_l2_offload)
+			rswitch_update_l2_offload(priv);
+		return;
+	}
+
+	if (offload_brdev && !priv->offload_brdev)
+		dev_info(&priv->pdev->dev, "starting l2 offload for %s\n",
+			 netdev_name(offload_brdev));
+	else if (!offload_brdev && priv->offload_brdev)
+		dev_info(&priv->pdev->dev, "stopping l2 offload for %s\n",
+			 netdev_name(priv->offload_brdev));
+	else
+		dev_info(&priv->pdev->dev,
+			 "changing l2 offload from %s to %s\n",
+			 netdev_name(priv->offload_brdev),
+			 netdev_name(offload_brdev));
+
+	priv->offload_brdev = offload_brdev;
+
+	rswitch_update_l2_offload(priv);
+}
+
+static bool rswitch_port_check(const struct net_device *ndev)
+{
+	return is_rdev(ndev);
+}
+
+static void rswitch_port_update_brdev(struct net_device *ndev,
+				      struct net_device *brdev)
+{
+	struct rswitch_device *rdev;
+
+	if (!is_rdev(ndev))
+		return;
+
+	rdev = netdev_priv(ndev);
+	rdev->brdev = brdev;
+	rswitch_update_offload_brdev(rdev->priv, false);
+}
+
+static int rswitch_port_update_stp_state(struct net_device *ndev, u8 stp_state)
+{
+	struct rswitch_device *rdev;
+
+	if (!is_rdev(ndev))
+		return -ENODEV;
+
+	rdev = netdev_priv(ndev);
+	rdev->learning_requested = (stp_state == BR_STATE_LEARNING ||
+				    stp_state == BR_STATE_FORWARDING);
+	rdev->forwarding_requested = (stp_state == BR_STATE_FORWARDING);
+	rswitch_update_l2_offload(rdev->priv);
+
+	return 0;
+}
+
+static int rswitch_netdevice_event(struct notifier_block *nb,
+				   unsigned long event, void *ptr)
+{
+	struct net_device *ndev = netdev_notifier_info_to_dev(ptr);
+	struct netdev_notifier_changeupper_info *info;
+	struct net_device *brdev;
+
+	if (!rswitch_port_check(ndev))
+		return NOTIFY_DONE;
+	if (event != NETDEV_CHANGEUPPER)
+		return NOTIFY_DONE;
+
+	info = ptr;
+
+	if (netif_is_bridge_master(info->upper_dev)) {
+		brdev = info->linking ? info->upper_dev : NULL;
+		rswitch_port_update_brdev(ndev, brdev);
+	}
+
+	return NOTIFY_OK;
+}
+
+static int rswitch_port_attr_set(struct net_device *ndev, const void *ctx,
+				 const struct switchdev_attr *attr,
+				 struct netlink_ext_ack *extack)
+{
+	switch (attr->id) {
+	case SWITCHDEV_ATTR_ID_PORT_STP_STATE:
+		return rswitch_port_update_stp_state(ndev, attr->u.stp_state);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int rswitch_port_obj_add(struct net_device *ndev, const void *ctx,
+				const struct switchdev_obj *obj,
+				struct netlink_ext_ack *extack)
+{
+	return -EOPNOTSUPP;
+}
+
+static int rswitch_port_obj_del(struct net_device *ndev, const void *ctx,
+				const struct switchdev_obj *obj)
+{
+	return -EOPNOTSUPP;
+}
+
+static int rswitch_switchdev_event(struct notifier_block *nb,
+				   unsigned long event, void *ptr)
+{
+	struct net_device *ndev = switchdev_notifier_info_to_dev(ptr);
+	int ret;
+
+	if (event == SWITCHDEV_PORT_ATTR_SET) {
+		ret = switchdev_handle_port_attr_set(ndev, ptr,
+						     rswitch_port_check,
+						     rswitch_port_attr_set);
+		return notifier_from_errno(ret);
+	}
+
+	if (!rswitch_port_check(ndev))
+		return NOTIFY_DONE;
+
+	return notifier_from_errno(-EOPNOTSUPP);
+}
+
+static int rswitch_switchdev_blocking_event(struct notifier_block *nb,
+					    unsigned long event, void *ptr)
+{
+	struct net_device *ndev = switchdev_notifier_info_to_dev(ptr);
+	int ret;
+
+	switch (event) {
+	case SWITCHDEV_PORT_OBJ_ADD:
+		ret = switchdev_handle_port_obj_add(ndev, ptr,
+						    rswitch_port_check,
+						    rswitch_port_obj_add);
+		break;
+	case SWITCHDEV_PORT_OBJ_DEL:
+		ret = switchdev_handle_port_obj_del(ndev, ptr,
+						    rswitch_port_check,
+						    rswitch_port_obj_del);
+		break;
+	case SWITCHDEV_PORT_ATTR_SET:
+		ret = switchdev_handle_port_attr_set(ndev, ptr,
+						     rswitch_port_check,
+						     rswitch_port_attr_set);
+		break;
+	default:
+		if (!rswitch_port_check(ndev))
+			return NOTIFY_DONE;
+		ret = -EOPNOTSUPP;
+	}
+
+	return notifier_from_errno(ret);
+}
+
+static struct notifier_block rswitch_netdevice_nb = {
+	.notifier_call = rswitch_netdevice_event,
+};
+
+static struct notifier_block rswitch_switchdev_nb = {
+	.notifier_call = rswitch_switchdev_event,
+};
+
+static struct notifier_block rswitch_switchdev_blocking_nb = {
+	.notifier_call = rswitch_switchdev_blocking_event,
+};
+
+int rswitch_register_notifiers(void)
+{
+	int ret;
+
+	ret = register_netdevice_notifier(&rswitch_netdevice_nb);
+	if (ret)
+		goto register_netdevice_notifier_failed;
+
+	ret = register_switchdev_notifier(&rswitch_switchdev_nb);
+	if (ret)
+		goto register_switchdev_notifier_failed;
+
+	ret = register_switchdev_blocking_notifier(&rswitch_switchdev_blocking_nb);
+	if (ret)
+		goto register_switchdev_blocking_notifier_failed;
+
+	return 0;
+
+register_switchdev_blocking_notifier_failed:
+	unregister_switchdev_notifier(&rswitch_switchdev_nb);
+register_switchdev_notifier_failed:
+	unregister_netdevice_notifier(&rswitch_netdevice_nb);
+register_netdevice_notifier_failed:
+
+	return ret;
+}
+
+void rswitch_unregister_notifiers(void)
+{
+	unregister_switchdev_blocking_notifier(&rswitch_switchdev_blocking_nb);
+	unregister_switchdev_notifier(&rswitch_switchdev_nb);
+	unregister_netdevice_notifier(&rswitch_netdevice_nb);
+}
diff --git a/drivers/net/ethernet/renesas/rswitch_l2.h b/drivers/net/ethernet/renesas/rswitch_l2.h
new file mode 100644
index 0000000000000000000000000000000000000000..57050ede8f31848cde5a497811a6ee1b60dedc65
--- /dev/null
+++ b/drivers/net/ethernet/renesas/rswitch_l2.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Renesas Ethernet Switch device driver
+ *
+ * Copyright (C) 2025 Renesas Electronics Corporation
+ */
+
+#ifndef __RSWITCH_L2_H__
+#define __RSWITCH_L2_H__
+
+void rswitch_update_l2_offload(struct rswitch_private *priv);
+
+int rswitch_register_notifiers(void);
+void rswitch_unregister_notifiers(void);
+
+#endif	/* #ifndef __RSWITCH_L2_H__ */
diff --git a/drivers/net/ethernet/renesas/rswitch_main.c b/drivers/net/ethernet/renesas/rswitch_main.c
index aba772e14555d30891dc74a5a123121dad77e92b..12689530e09385b7912b25fa1b982bfd637948d4 100644
--- a/drivers/net/ethernet/renesas/rswitch_main.c
+++ b/drivers/net/ethernet/renesas/rswitch_main.c
@@ -1,15 +1,18 @@
 // SPDX-License-Identifier: GPL-2.0
 /* Renesas Ethernet Switch device driver
  *
- * Copyright (C) 2022 Renesas Electronics Corporation
+ * Copyright (C) 2022-2025 Renesas Electronics Corporation
  */
 
 #include <linux/clk.h>
 #include <linux/dma-mapping.h>
 #include <linux/err.h>
 #include <linux/etherdevice.h>
+#include <linux/ethtool.h>
+#include <linux/ip.h>
 #include <linux/iopoll.h>
 #include <linux/kernel.h>
+#include <linux/list.h>
 #include <linux/module.h>
 #include <linux/net_tstamp.h>
 #include <linux/of.h>
@@ -25,6 +28,7 @@
 #include <linux/sys_soc.h>
 
 #include "rswitch.h"
+#include "rswitch_l2.h"
 
 static int rswitch_reg_wait(void __iomem *addr, u32 offs, u32 mask, u32 expected)
 {
@@ -34,7 +38,7 @@ static int rswitch_reg_wait(void __iomem *addr, u32 offs, u32 mask, u32 expected
 					 1, RSWITCH_TIMEOUT_US);
 }
 
-static void rswitch_modify(void __iomem *addr, enum rswitch_reg reg, u32 clear, u32 set)
+void rswitch_modify(void __iomem *addr, enum rswitch_reg reg, u32 clear, u32 set)
 {
 	iowrite32((ioread32(addr + reg) & ~clear) | set, addr + reg);
 }
@@ -109,10 +113,12 @@ static void rswitch_top_init(struct rswitch_private *priv)
 }
 
 /* Forwarding engine block (MFWD) */
-static void rswitch_fwd_init(struct rswitch_private *priv)
+static int rswitch_fwd_init(struct rswitch_private *priv)
 {
 	u32 all_ports_mask = GENMASK(RSWITCH_NUM_AGENTS - 1, 0);
 	unsigned int i;
+	u32 reg_val;
+	u32 ret;
 
 	/* Start with empty configuration */
 	for (i = 0; i < RSWITCH_NUM_AGENTS; i++) {
@@ -128,6 +134,14 @@ static void rswitch_fwd_init(struct rswitch_private *priv)
 		iowrite32(0, priv->addr + FWPBFC(i));
 	}
 
+	/* Configure MAC table aging */
+	rswitch_modify(priv->addr, FWMACAGUSPC, FWMACAGUSPC_MACAGUSP,
+		       FIELD_PREP(FWMACAGUSPC_MACAGUSP, 0x140));
+
+	reg_val = FIELD_PREP(FWMACAGC_MACAGT, RSW_AGEING_TIME);
+	reg_val |= FWMACAGC_MACAGE | FWMACAGC_MACAGSL;
+	iowrite32(reg_val, priv->addr + FWMACAGC);
+
 	/* For enabled ETHA ports, setup port based forwarding */
 	rswitch_for_each_enabled_port(priv, i) {
 		/* Port based forwarding from port i to GWCA port */
@@ -140,6 +154,17 @@ static void rswitch_fwd_init(struct rswitch_private *priv)
 
 	/* For GWCA port, allow direct descriptor forwarding */
 	rswitch_modify(priv->addr, FWPC1(priv->gwca.index), FWPC1_DDE, FWPC1_DDE);
+
+	/* Initialize hardware L2 forwarding table */
+
+	/* Allow entire table to be used for "unsecure" entries */
+	rswitch_modify(priv->addr, FWMACHEC, 0, FWMACHEC_MACHMUE_MASK);
+
+	/* Initialize MAC hash table */
+	iowrite32(FWMACTIM_MACTIOG, priv->addr + FWMACTIM);
+	ret = rswitch_reg_wait(priv->addr, FWMACTIM, FWMACTIM_MACTIOG, 0);
+
+	return ret;
 }
 
 /* Gateway CPU agent block (GWCA) */
@@ -1602,6 +1627,9 @@ static int rswitch_open(struct net_device *ndev)
 
 	netif_start_queue(ndev);
 
+	if (rdev->brdev)
+		rswitch_update_l2_offload(rdev->priv);
+
 	return 0;
 };
 
@@ -1624,6 +1652,9 @@ static int rswitch_stop(struct net_device *ndev)
 
 	napi_disable(&rdev->napi);
 
+	if (rdev->brdev)
+		rswitch_update_l2_offload(rdev->priv);
+
 	if (bitmap_empty(rdev->priv->opened_ports, RSWITCH_NUM_PORTS))
 		iowrite32(GWCA_TS_IRQ_BIT, rdev->priv->addr + GWTSDID);
 
@@ -1850,16 +1881,46 @@ static int rswitch_eth_ioctl(struct net_device *ndev, struct ifreq *req, int cmd
 	}
 }
 
+static int rswitch_get_port_parent_id(struct net_device *ndev,
+				      struct netdev_phys_item_id *ppid)
+{
+	struct rswitch_device *rdev = netdev_priv(ndev);
+	const char *name;
+
+	name = dev_name(&rdev->priv->pdev->dev);
+	ppid->id_len = min_t(size_t, strlen(name), sizeof(ppid->id_len));
+	memcpy(ppid->id, name, ppid->id_len);
+
+	return 0;
+}
+
+static int rswitch_get_phys_port_name(struct net_device *ndev,
+				      char *name, size_t len)
+{
+	struct rswitch_device *rdev = netdev_priv(ndev);
+
+	snprintf(name, len, "tsn%d", rdev->port);
+
+	return 0;
+}
+
 static const struct net_device_ops rswitch_netdev_ops = {
 	.ndo_open = rswitch_open,
 	.ndo_stop = rswitch_stop,
 	.ndo_start_xmit = rswitch_start_xmit,
 	.ndo_get_stats = rswitch_get_stats,
 	.ndo_eth_ioctl = rswitch_eth_ioctl,
+	.ndo_get_port_parent_id = rswitch_get_port_parent_id,
+	.ndo_get_phys_port_name = rswitch_get_phys_port_name,
 	.ndo_validate_addr = eth_validate_addr,
 	.ndo_set_mac_address = eth_mac_addr,
 };
 
+bool is_rdev(const struct net_device *ndev)
+{
+	return (ndev->netdev_ops == &rswitch_netdev_ops);
+}
+
 static int rswitch_get_ts_info(struct net_device *ndev, struct kernel_ethtool_ts_info *info)
 {
 	struct rswitch_device *rdev = netdev_priv(ndev);
@@ -1959,6 +2020,8 @@ static int rswitch_device_alloc(struct rswitch_private *priv, unsigned int index
 	if (err < 0)
 		goto out_txdmac;
 
+	list_add_tail(&rdev->list, &priv->port_list);
+
 	return 0;
 
 out_txdmac:
@@ -1978,6 +2041,7 @@ static void rswitch_device_free(struct rswitch_private *priv, unsigned int index
 	struct rswitch_device *rdev = priv->rdev[index];
 	struct net_device *ndev = rdev->ndev;
 
+	list_del(&rdev->list);
 	rswitch_txdmac_free(ndev);
 	rswitch_rxdmac_free(ndev);
 	of_node_put(rdev->np_port);
@@ -2024,7 +2088,9 @@ static int rswitch_init(struct rswitch_private *priv)
 		}
 	}
 
-	rswitch_fwd_init(priv);
+	err = rswitch_fwd_init(priv);
+	if (err < 0)
+		goto err_fwd_init;
 
 	err = rcar_gen4_ptp_register(priv->ptp_priv, RCAR_GEN4_PTP_REG_LAYOUT,
 				     clk_get_rate(priv->clk));
@@ -2073,6 +2139,7 @@ static int rswitch_init(struct rswitch_private *priv)
 err_gwca_request_irq:
 	rcar_gen4_ptp_unregister(priv->ptp_priv);
 
+err_fwd_init:
 err_ptp_register:
 	for (i = 0; i < RSWITCH_NUM_PORTS; i++)
 		rswitch_device_free(priv, i);
@@ -2107,6 +2174,7 @@ static int renesas_eth_sw_probe(struct platform_device *pdev)
 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
+
 	spin_lock_init(&priv->lock);
 
 	priv->clk = devm_clk_get(&pdev->dev, NULL);
@@ -2144,6 +2212,8 @@ static int renesas_eth_sw_probe(struct platform_device *pdev)
 	if (!priv->gwca.queues)
 		return -ENOMEM;
 
+	INIT_LIST_HEAD(&priv->port_list);
+
 	pm_runtime_enable(&pdev->dev);
 	pm_runtime_get_sync(&pdev->dev);
 
@@ -2154,6 +2224,15 @@ static int renesas_eth_sw_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	if (list_empty(&priv->port_list))
+		dev_warn(&pdev->dev, "could not initialize any ports\n");
+
+	ret = rswitch_register_notifiers();
+	if (ret) {
+		dev_err(&pdev->dev, "could not register notifiers\n");
+		return ret;
+	}
+
 	device_set_wakeup_capable(&pdev->dev, 1);
 
 	return ret;
@@ -2187,6 +2266,7 @@ static void renesas_eth_sw_remove(struct platform_device *pdev)
 {
 	struct rswitch_private *priv = platform_get_drvdata(pdev);
 
+	rswitch_unregister_notifiers();
 	rswitch_deinit(priv);
 
 	pm_runtime_put(&pdev->dev);

-- 
2.49.0

>  #include <linux/platform_device.h>
> +#include <linux/phy.h>
> +

It seems odd that a patch adding L2 support needs to touch PHYs?

> @@ -994,10 +1018,18 @@ struct rswitch_device {
>  	DECLARE_BITMAP(ts_skb_used, TS_TAGS_PER_PORT);
>  	bool disabled;
>  
> +	struct list_head list;
> +
>  	int port;
>  	struct rswitch_etha *etha;
>  	struct device_node *np_port;
>  	struct phy *serdes;
> +
> +	struct net_device *brdev;	/* master bridge device */

How many ports does this device have? If it is just two, this might
work. But for a multi-port device, you need to keep this in the port
structure.

> +bool is_rdev(const struct net_device *ndev);
> +void rswitch_modify(void __iomem *addr, enum rswitch_reg reg, u32 clear, u32 set);

Are these actually needed? It seems like they could be local
functions.

> +	if (offload_brdev && !priv->offload_brdev)
> +		dev_info(&priv->pdev->dev, "starting l2 offload for %s\n",
> +			 netdev_name(offload_brdev));
> +	else if (!offload_brdev && priv->offload_brdev)
> +		dev_info(&priv->pdev->dev, "stopping l2 offload for %s\n",
> +			 netdev_name(priv->offload_brdev));

Please don't spam the log like this dev_dbg() maybe.

> @@ -128,6 +134,14 @@ static void rswitch_fwd_init(struct rswitch_private *priv)
>  		iowrite32(0, priv->addr + FWPBFC(i));
>  	}
>  
> +	/* Configure MAC table aging */
> +	rswitch_modify(priv->addr, FWMACAGUSPC, FWMACAGUSPC_MACAGUSP,
> +		       FIELD_PREP(FWMACAGUSPC_MACAGUSP, 0x140));
> +
> +	reg_val = FIELD_PREP(FWMACAGC_MACAGT, RSW_AGEING_TIME);
> +	reg_val |= FWMACAGC_MACAGE | FWMACAGC_MACAGSL;
> +	iowrite32(reg_val, priv->addr + FWMACAGC);
> +

Please pull ageing out into a patch of its own.

    Andrew

---
pw-bot: cr

>>   	struct phy *serdes;
>> +
>> +	struct net_device *brdev;	/* master bridge device */
> 
> How many ports does this device have? If it is just two, this might
> work. But for a multi-port device, you need to keep this in the port
> structure.

Having per-device (not per port) brdev was designed by me.  Reasoning is that hw L2 forwarding support 
lacks any sort of source port based filtering, which makes it unusable to offload more than one bridge 
device. Either you allow hardware to forward destination MAC to a port, or you have to send it to CPU. 
You can't make it forward only if src and dst ports are in the same brdev.

There are 3 ports in the S4 SoC, but the rswitch IP is parametrized so any number of ports could be 
possible. And, we have been implementing virtual ports (not yet in the patchset by Michael) which opened 
possibility to have netdevs of the same rswitch to be in multiple brdevs even on S4. But still had to 
limit to one brdev due to that hw limitation.

There could be a theoretical possibility to use hw L3 forwarding features for better L2 forwarding, but 
that is tricky and creating such a design did not succeed so far.

Nikita

On Fri, Jul 04, 2025 at 11:02:55AM +0200, Nikita Yushchenko wrote:
> > >   	struct phy *serdes;
> > > +
> > > +	struct net_device *brdev;	/* master bridge device */
> > 
> > How many ports does this device have? If it is just two, this might
> > work. But for a multi-port device, you need to keep this in the port
> > structure.
> 
> Having per-device (not per port) brdev was designed by me.  Reasoning is
> that hw L2 forwarding support lacks any sort of source port based filtering,
> which makes it unusable to offload more than one bridge device. Either you
> allow hardware to forward destination MAC to a port, or you have to send it
> to CPU. You can't make it forward only if src and dst ports are in the same
> brdev.

This needs to be part of the commit message, since it is not
obvious. I think some comments in the code would also be good, where
it decides there is a bridge in use, and so it needs to reject the
offload for another bridge. This limitation is very unusual, pretty
much a design error, so it needs calling out.

	Andrew