From 51a4a22301b023610a1321614e8dc61251ef9064 Mon Sep 17 00:00:00 2001
From: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Date: Sat, 6 Jun 2026 05:29:27 -0300
Subject: net: dsa: realtek: rtl8365mb: use dsa helpers for port iteration

Convert open-coded port iteration loops to use the DSA helpers and
restructure rtl8365mb_setup() into clear blocking, user, and
CPU port phases.

As part of this refactoring, unused ports are explicitly placed into a
blocked, isolated state with learning disabled, ensuring safe default
hardware behavior. The driver also does not allocate a virtual IRQ
mapping for unused ports. To accommodate this, a guard check is added to
the interrupt handler (rtl8365mb_irq) to safely skip ports without a
valid IRQ mapping. The irq domain teardown, however, does clean all
ports as external PHYs may still map the IRQ.

Furthermore, since the new initialization loop starts with all ports
administratively isolated by default, CPU port forwarding and isolation
masks are explicitly configured at the end of the setup phase to prevent
egress traffic from being blocked.

Suggested-by: Abdulkader Alrezej <abdulkader.alrezej@gmail.com>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Reviewed-by: Mieczyslaw Nalewaj <namiltd@yahoo.com>
Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Link: https://patch.msgid.link/20260606-realtek_forward-v13-3-b9e409687cbe@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 drivers/net/dsa/realtek/rtl8365mb.c | 166 +++++++++++++++++++++++-------------
 1 file changed, 105 insertions(+), 61 deletions(-)

--- a/drivers/net/dsa/realtek/rtl8365mb.c
+++ b/drivers/net/dsa/realtek/rtl8365mb.c
@@ -1554,18 +1554,15 @@ static void rtl8365mb_stats_setup(struct
 {
 	struct rtl8365mb *mb = priv->chip_data;
 	struct dsa_switch *ds = &priv->ds;
-	int i;
+	struct dsa_port *dp;
 
 	/* Per-chip global mutex to protect MIB counter access, since doing
 	 * so requires accessing a series of registers in a particular order.
 	 */
 	mutex_init(&mb->mib_lock);
 
-	for (i = 0; i < priv->num_ports; i++) {
-		struct rtl8365mb_port *p = &mb->ports[i];
-
-		if (dsa_is_unused_port(ds, i))
-			continue;
+	dsa_switch_for_each_available_port(dp, ds) {
+		struct rtl8365mb_port *p = &mb->ports[dp->index];
 
 		/* Per-port spinlock to protect the stats64 data */
 		spin_lock_init(&p->stats_lock);
@@ -1581,13 +1578,10 @@ static void rtl8365mb_stats_teardown(str
 {
 	struct rtl8365mb *mb = priv->chip_data;
 	struct dsa_switch *ds = &priv->ds;
-	int i;
-
-	for (i = 0; i < priv->num_ports; i++) {
-		struct rtl8365mb_port *p = &mb->ports[i];
+	struct dsa_port *dp;
 
-		if (dsa_is_unused_port(ds, i))
-			continue;
+	dsa_switch_for_each_available_port(dp, ds) {
+		struct rtl8365mb_port *p = &mb->ports[dp->index];
 
 		cancel_delayed_work_sync(&p->mib_work);
 	}
@@ -1646,6 +1640,9 @@ static irqreturn_t rtl8365mb_irq(int irq
 	for_each_set_bit(line, &line_changes, priv->num_ports) {
 		int child_irq = irq_find_mapping(priv->irqdomain, line);
 
+		if (!child_irq)
+			continue;
+
 		handle_nested_irq(child_irq);
 	}
 
@@ -1667,10 +1664,14 @@ static struct irq_chip rtl8365mb_irq_chi
 static int rtl8365mb_irq_map(struct irq_domain *domain, unsigned int irq,
 			     irq_hw_number_t hwirq)
 {
-	irq_set_chip_data(irq, domain->host_data);
+	struct realtek_priv *priv = domain->host_data;
+	struct rtl8365mb *mb = priv->chip_data;
+
+	irq_set_chip_data(irq, priv);
 	irq_set_chip_and_handler(irq, &rtl8365mb_irq_chip, handle_simple_irq);
 	irq_set_nested_thread(irq, 1);
 	irq_set_noprobe(irq);
+	irq_set_parent(irq, mb->irq);
 
 	return 0;
 }
@@ -1709,13 +1710,14 @@ static int rtl8365mb_irq_disable(struct
 static int rtl8365mb_irq_setup(struct realtek_priv *priv)
 {
 	struct rtl8365mb *mb = priv->chip_data;
+	struct dsa_switch *ds = &priv->ds;
 	struct device_node *intc;
+	struct dsa_port *dp;
 	u32 irq_trig;
 	int virq;
 	int irq;
 	u32 val;
 	int ret;
-	int i;
 
 	intc = of_get_child_by_name(priv->dev->of_node, "interrupt-controller");
 	if (!intc) {
@@ -1736,6 +1738,9 @@ static int rtl8365mb_irq_setup(struct re
 		goto out_put_node;
 	}
 
+	/* Store the irq so that we know to map and free it during teardown */
+	mb->irq = irq;
+
 	priv->irqdomain = irq_domain_add_linear(intc, priv->num_ports,
 						&rtl8365mb_irqdomain_ops, priv);
 	if (!priv->irqdomain) {
@@ -1744,8 +1749,8 @@ static int rtl8365mb_irq_setup(struct re
 		goto out_put_node;
 	}
 
-	for (i = 0; i < priv->num_ports; i++) {
-		virq = irq_create_mapping(priv->irqdomain, i);
+	dsa_switch_for_each_available_port(dp, ds) {
+		virq = irq_create_mapping(priv->irqdomain, dp->index);
 		if (!virq) {
 			dev_err(priv->dev,
 				"failed to create irq domain mapping\n");
@@ -1799,9 +1804,6 @@ static int rtl8365mb_irq_setup(struct re
 		goto out_remove_irqdomain;
 	}
 
-	/* Store the irq so that we know to free it during teardown */
-	mb->irq = irq;
-
 	ret = rtl8365mb_irq_enable(priv);
 	if (ret)
 		goto out_free_irq;
@@ -1812,18 +1814,20 @@ static int rtl8365mb_irq_setup(struct re
 
 out_free_irq:
 	free_irq(mb->irq, priv);
-	mb->irq = 0;
 
 out_remove_irqdomain:
-	for (i = 0; i < priv->num_ports; i++) {
-		virq = irq_find_mapping(priv->irqdomain, i);
-		irq_dispose_mapping(virq);
+	dsa_switch_for_each_port(dp, ds) {
+		virq = irq_find_mapping(priv->irqdomain, dp->index);
+
+		if (virq)
+			irq_dispose_mapping(virq);
 	}
 
 	irq_domain_remove(priv->irqdomain);
 	priv->irqdomain = NULL;
 
 out_put_node:
+	mb->irq = 0;
 	of_node_put(intc);
 
 	return ret;
@@ -1832,8 +1836,9 @@ out_put_node:
 static void rtl8365mb_irq_teardown(struct realtek_priv *priv)
 {
 	struct rtl8365mb *mb = priv->chip_data;
+	struct dsa_switch *ds = &priv->ds;
+	struct dsa_port *dp;
 	int virq;
-	int i;
 
 	if (mb->irq) {
 		free_irq(mb->irq, priv);
@@ -1841,9 +1846,15 @@ static void rtl8365mb_irq_teardown(struc
 	}
 
 	if (priv->irqdomain) {
-		for (i = 0; i < priv->num_ports; i++) {
-			virq = irq_find_mapping(priv->irqdomain, i);
-			irq_dispose_mapping(virq);
+		/* Unused ports with a linked PHY still have an active IRQ
+		 * mapping that must be disposed of during teardown. Loop
+		 * through all ports.
+		 */
+		dsa_switch_for_each_port(dp, ds) {
+			virq = irq_find_mapping(priv->irqdomain, dp->index);
+
+			if (virq)
+				irq_dispose_mapping(virq);
 		}
 
 		irq_domain_remove(priv->irqdomain);
@@ -1961,10 +1972,11 @@ static int rtl8365mb_setup(struct dsa_sw
 {
 	struct realtek_priv *priv = ds->priv;
 	struct rtl8365mb_cpu *cpu;
-	struct dsa_port *cpu_dp;
+	u32 downports_mask = 0;
+	u32 upports_mask = 0;
 	struct rtl8365mb *mb;
+	struct dsa_port *dp;
 	int ret;
-	int i;
 
 	mb = priv->chip_data;
 	cpu = &mb->cpu;
@@ -1991,67 +2003,99 @@ static int rtl8365mb_setup(struct dsa_sw
 	else if (ret)
 		dev_info(priv->dev, "no interrupt support\n");
 
-	for (i = 0; i < priv->num_ports; i++) {
+	dsa_switch_for_each_port(dp, ds) {
 		/* Cascading (DSA links) is not supported yet.
 		 * Historically, the driver has always been broken
 		 * without a dedicated CPU port because CPU tagging
 		 * would be disabled, rendering the switch entirely
 		 * non-functional for DSA operations.
 		 */
-		if (dsa_is_dsa_port(ds, i)) {
+		if (dsa_port_is_dsa(dp)) {
 			dev_err(priv->dev, "Cascading (DSA link) not supported\n");
 			ret = -EOPNOTSUPP;
 			goto out_teardown_irq;
 		}
 	}
 
-	/* Configure CPU tagging */
-	dsa_switch_for_each_cpu_port(cpu_dp, ds) {
-		cpu->mask |= BIT(cpu_dp->index);
+	/* Start with all ports blocked, including unused ports */
+	dsa_switch_for_each_port(dp, ds) {
+		struct rtl8365mb_port *p = &mb->ports[dp->index];
 
-		if (cpu->trap_port == RTL8365MB_MAX_NUM_PORTS)
-			cpu->trap_port = cpu_dp->index;
-	}
-	cpu->enable = cpu->mask > 0;
+		/* Set the initial STP state of all ports to DISABLED, otherwise
+		 * ports will still forward frames to the CPU despite being
+		 * administratively down by default.
+		 */
+		rtl8365mb_port_stp_state_set(ds, dp->index, BR_STATE_DISABLED);
 
-	if (!cpu->enable) {
-		dev_err(priv->dev, "no CPU port defined\n");
-		ret = -EINVAL;
-		goto out_teardown_irq;
-	}
+		/* Start with all port completely isolated */
+		ret = rtl8365mb_port_set_isolation(priv, dp->index, 0);
+		if (ret)
+			goto out_teardown_irq;
 
-	ret = rtl8365mb_cpu_config(priv);
-	if (ret)
-		goto out_teardown_irq;
+		/* Disable learning */
+		ret = rtl8365mb_port_set_learning(priv, dp->index, false);
+		if (ret)
+			goto out_teardown_irq;
+
+		/* Set up per-port private data */
+		p->priv = priv;
+		p->index = dp->index;
 
-	/* Configure ports */
-	for (i = 0; i < priv->num_ports; i++) {
-		struct rtl8365mb_port *p = &mb->ports[i];
+		/* Collect CPU ports. If we support cascade switches, it should
+		 * also include the upstream DSA ports.
+		 */
+		if (!dsa_port_is_cpu(dp))
+			continue;
+
+		upports_mask |= BIT(dp->index);
+	}
 
-		if (dsa_is_unused_port(ds, i))
+	/* Configure user ports */
+	dsa_switch_for_each_port(dp, ds) {
+		if (!dsa_port_is_user(dp))
 			continue;
 
 		/* Forward only to the CPU */
-		ret = rtl8365mb_port_set_isolation(priv, i, cpu->mask);
+		ret = rtl8365mb_port_set_isolation(priv, dp->index,
+						   upports_mask);
 		if (ret)
 			goto out_teardown_irq;
 
-		/* Disable learning */
-		ret = rtl8365mb_port_set_learning(priv, i, false);
+		/* If we support cascade switches, it should also include the
+		 * downstream DSA ports.
+		 */
+		downports_mask |= BIT(dp->index);
+	}
+
+	/* Configure CPU tagging */
+	/* If we support cascade switches, it should also include the upstream
+	 * DSA ports.
+	 */
+	dsa_switch_for_each_cpu_port(dp, ds) {
+		/* Use the first CPU port as trap_port */
+		if (cpu->trap_port == RTL8365MB_MAX_NUM_PORTS)
+			cpu->trap_port = dp->index;
+
+		/* Forward to all user ports */
+		ret = rtl8365mb_port_set_isolation(priv, dp->index,
+						   downports_mask);
 		if (ret)
 			goto out_teardown_irq;
+	}
 
-		/* Set the initial STP state of all ports to DISABLED, otherwise
-		 * ports will still forward frames to the CPU despite being
-		 * administratively down by default.
-		 */
-		rtl8365mb_port_stp_state_set(ds, i, BR_STATE_DISABLED);
+	cpu->mask = upports_mask;
+	cpu->enable = cpu->mask > 0;
 
-		/* Set up per-port private data */
-		p->priv = priv;
-		p->index = i;
+	if (!cpu->enable) {
+		dev_err(priv->dev, "no CPU port defined\n");
+		ret = -EINVAL;
+		goto out_teardown_irq;
 	}
 
+	ret = rtl8365mb_cpu_config(priv);
+	if (ret)
+		goto out_teardown_irq;
+
 	ret = rtl8365mb_port_change_mtu(ds, cpu->trap_port, ETH_DATA_LEN);
 	if (ret)
 		goto out_teardown_irq;
