4 files changed, 91 insertions, 16 deletions

diff --git a/drivers/net/dsa/microchip/ksz9477.c b/drivers/net/dsa/microchip/ksz9477.c
index d747ea1c41a7..5df8f153d511 100644
--- a/drivers/net/dsa/microchip/ksz9477.c
+++ b/drivers/net/dsa/microchip/ksz9477.c
@@ -1355,9 +1355,15 @@ void ksz9477_config_cpu_port(struct dsa_switch *ds)
 	}
 }
 
+#define RESV_MCAST_CNT	8
+
+static u8 reserved_mcast_map[RESV_MCAST_CNT] = { 0, 1, 3, 16, 32, 33, 2, 17 };
+
 int ksz9477_enable_stp_addr(struct ksz_device *dev)
 {
+	u8 i, ports, update;
 	const u32 *masks;
+	bool override;
 	u32 data;
 	int ret;
 
@@ -1366,23 +1372,87 @@ int ksz9477_enable_stp_addr(struct ksz_device *dev)
 	/* Enable Reserved multicast table */
 	ksz_cfg(dev, REG_SW_LUE_CTRL_0, SW_RESV_MCAST_ENABLE, true);
 
-	/* Set the Override bit for forwarding BPDU packet to CPU */
-	ret = ksz_write32(dev, REG_SW_ALU_VAL_B,
-			  ALU_V_OVERRIDE | BIT(dev->cpu_port));
-	if (ret < 0)
-		return ret;
+	/* The reserved multicast address table has 8 entries.  Each entry has
+	 * a default value of which port to forward.  It is assumed the host
+	 * port is the last port in most of the switches, but that is not the
+	 * case for KSZ9477 or maybe KSZ9897.  For LAN937X family the default
+	 * port is port 5, the first RGMII port.  It is okay for LAN9370, a
+	 * 5-port switch, but may not be correct for the other 8-port
+	 * versions.  It is necessary to update the whole table to forward to
+	 * the right ports.
+	 * Furthermore PTP messages can use a reserved multicast address and
+	 * the host will not receive them if this table is not correct.
+	 */
+	for (i = 0; i < RESV_MCAST_CNT; i++) {
+		data = reserved_mcast_map[i] <<
+			dev->info->shifts[ALU_STAT_INDEX];
+		data |= ALU_STAT_START |
+			masks[ALU_STAT_DIRECT] |
+			masks[ALU_RESV_MCAST_ADDR] |
+			masks[ALU_STAT_READ];
+		ret = ksz_write32(dev, REG_SW_ALU_STAT_CTRL__4, data);
+		if (ret < 0)
+			return ret;
 
-	data = ALU_STAT_START | ALU_RESV_MCAST_ADDR | masks[ALU_STAT_WRITE];
+		/* wait to be finished */
+		ret = ksz9477_wait_alu_sta_ready(dev);
+		if (ret < 0)
+			return ret;
 
-	ret = ksz_write32(dev, REG_SW_ALU_STAT_CTRL__4, data);
-	if (ret < 0)
-		return ret;
+		ret = ksz_read32(dev, REG_SW_ALU_VAL_B, &data);
+		if (ret < 0)
+			return ret;
 
-	/* wait to be finished */
-	ret = ksz9477_wait_alu_sta_ready(dev);
-	if (ret < 0) {
-		dev_err(dev->dev, "Failed to update Reserved Multicast table\n");
-		return ret;
+		override = false;
+		ports = data & dev->port_mask;
+		switch (i) {
+		case 0:
+		case 6:
+			/* Change the host port. */
+			update = BIT(dev->cpu_port);
+			override = true;
+			break;
+		case 2:
+			/* Change the host port. */
+			update = BIT(dev->cpu_port);
+			break;
+		case 4:
+		case 5:
+		case 7:
+			/* Skip the host port. */
+			update = dev->port_mask & ~BIT(dev->cpu_port);
+			break;
+		default:
+			update = ports;
+			break;
+		}
+		if (update != ports || override) {
+			data &= ~dev->port_mask;
+			data |= update;
+			/* Set Override bit to receive frame even when port is
+			 * closed.
+			 */
+			if (override)
+				data |= ALU_V_OVERRIDE;
+			ret = ksz_write32(dev, REG_SW_ALU_VAL_B, data);
+			if (ret < 0)
+				return ret;
+
+			data = reserved_mcast_map[i] <<
+			       dev->info->shifts[ALU_STAT_INDEX];
+			data |= ALU_STAT_START |
+				masks[ALU_STAT_DIRECT] |
+				masks[ALU_RESV_MCAST_ADDR] |
+				masks[ALU_STAT_WRITE];
+			ret = ksz_write32(dev, REG_SW_ALU_STAT_CTRL__4, data);
+			if (ret < 0)
+				return ret;
+
+			/* wait to be finished */
+			ret = ksz9477_wait_alu_sta_ready(dev);
+			if (ret < 0)
+				return ret;
+		}
 	}
 
 	return 0;
diff --git a/drivers/net/dsa/microchip/ksz9477_reg.h b/drivers/net/dsa/microchip/ksz9477_reg.h
index ff579920078e..61ea11e3338e 100644
--- a/drivers/net/dsa/microchip/ksz9477_reg.h
+++ b/drivers/net/dsa/microchip/ksz9477_reg.h
@@ -2,7 +2,7 @@
 /*
  * Microchip KSZ9477 register definitions
  *
- * Copyright (C) 2017-2024 Microchip Technology Inc.
+ * Copyright (C) 2017-2025 Microchip Technology Inc.
  */
 
 #ifndef __KSZ9477_REGS_H
@@ -397,7 +397,6 @@
 
 #define ALU_RESV_MCAST_INDEX_M		(BIT(6) - 1)
 #define ALU_STAT_START			BIT(7)
-#define ALU_RESV_MCAST_ADDR		BIT(1)
 
 #define REG_SW_ALU_VAL_A		0x0420
 
diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c
index a962055bfdbd..933ae8dc6337 100644
--- a/drivers/net/dsa/microchip/ksz_common.c
+++ b/drivers/net/dsa/microchip/ksz_common.c
@@ -808,6 +808,8 @@ static const u16 ksz9477_regs[] = {
 static const u32 ksz9477_masks[] = {
 	[ALU_STAT_WRITE]		= 0,
 	[ALU_STAT_READ]			= 1,
+	[ALU_STAT_DIRECT]		= 0,
+	[ALU_RESV_MCAST_ADDR]		= BIT(1),
 	[P_MII_TX_FLOW_CTRL]		= BIT(5),
 	[P_MII_RX_FLOW_CTRL]		= BIT(3),
 };
@@ -835,6 +837,8 @@ static const u8 ksz9477_xmii_ctrl1[] = {
 static const u32 lan937x_masks[] = {
 	[ALU_STAT_WRITE]		= 1,
 	[ALU_STAT_READ]			= 2,
+	[ALU_STAT_DIRECT]		= BIT(3),
+	[ALU_RESV_MCAST_ADDR]		= BIT(2),
 	[P_MII_TX_FLOW_CTRL]		= BIT(5),
 	[P_MII_RX_FLOW_CTRL]		= BIT(3),
 };
diff --git a/drivers/net/dsa/microchip/ksz_common.h b/drivers/net/dsa/microchip/ksz_common.h
index a1eb39771bb9..c65188cd3c0a 100644
--- a/drivers/net/dsa/microchip/ksz_common.h
+++ b/drivers/net/dsa/microchip/ksz_common.h
@@ -294,6 +294,8 @@ enum ksz_masks {
 	DYNAMIC_MAC_TABLE_TIMESTAMP,
 	ALU_STAT_WRITE,
 	ALU_STAT_READ,
+	ALU_STAT_DIRECT,
+	ALU_RESV_MCAST_ADDR,
 	P_MII_TX_FLOW_CTRL,
 	P_MII_RX_FLOW_CTRL,
 };