net: dsa: qca8k: add support for cpu port 6

Currently CPU port is always hardcoded to port 0. This switch have 2 CPU
ports. The original intention of this driver seems to be use the
mac06_exchange bit to swap MAC0 with MAC6 in the strange configuration
where device have connected only the CPU port 6. To skip the
introduction of a new binding, rework the driver to address the
secondary CPU port as primary and drop any reference of hardcoded port.
With configuration of mac06 exchange, just skip the definition of port0
and define the CPU port as a secondary. The driver will autoconfigure
the switch to use that as the primary CPU port.

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/qca8k.c

@@ -977,6 +977,22 @@ qca8k_setup_mac_pwr_sel(struct qca8k_priv *priv)
 	return ret;
 }
 
+static int qca8k_find_cpu_port(struct dsa_switch *ds)
+{
+	struct qca8k_priv *priv = ds->priv;
+
+	/* Find the connected cpu port. Valid port are 0 or 6 */
+	if (dsa_is_cpu_port(ds, 0))
+		return 0;
+
+	dev_dbg(priv->dev, "port 0 is not the CPU port. Checking port 6");
+
+	if (dsa_is_cpu_port(ds, 6))
+		return 6;
+
+	return -EINVAL;
+}
+
 static int
 qca8k_parse_port_config(struct qca8k_priv *priv)
 {
@@ -1017,13 +1033,13 @@ static int
 qca8k_setup(struct dsa_switch *ds)
 {
 	struct qca8k_priv *priv = (struct qca8k_priv *)ds->priv;
-	int ret, i;
+	int cpu_port, ret, i;
 	u32 mask;
 
-	/* Make sure that port 0 is the cpu port */
-	if (!dsa_is_cpu_port(ds, 0)) {
-		dev_err(priv->dev, "port 0 is not the CPU port");
-		return -EINVAL;
+	cpu_port = qca8k_find_cpu_port(ds);
+	if (cpu_port < 0) {
+		dev_err(priv->dev, "No cpu port configured in both cpu port0 and port6");
+		return cpu_port;
 	}
 
 	/* Parse CPU port config to be later used in phy_link mac_config */
@@ -1065,7 +1081,7 @@ qca8k_setup(struct dsa_switch *ds)
 		dev_warn(priv->dev, "mib init failed");
 
 	/* Enable QCA header mode on the cpu port */
-	ret = qca8k_write(priv, QCA8K_REG_PORT_HDR_CTRL(QCA8K_CPU_PORT),
+	ret = qca8k_write(priv, QCA8K_REG_PORT_HDR_CTRL(cpu_port),
 			  QCA8K_PORT_HDR_CTRL_ALL << QCA8K_PORT_HDR_CTRL_TX_S |
 			  QCA8K_PORT_HDR_CTRL_ALL << QCA8K_PORT_HDR_CTRL_RX_S);
 	if (ret) {
@@ -1087,18 +1103,18 @@ qca8k_setup(struct dsa_switch *ds)
 
 	/* Forward all unknown frames to CPU port for Linux processing */
 	ret = qca8k_write(priv, QCA8K_REG_GLOBAL_FW_CTRL1,
-			  BIT(0) << QCA8K_GLOBAL_FW_CTRL1_IGMP_DP_S |
-			  BIT(0) << QCA8K_GLOBAL_FW_CTRL1_BC_DP_S |
-			  BIT(0) << QCA8K_GLOBAL_FW_CTRL1_MC_DP_S |
-			  BIT(0) << QCA8K_GLOBAL_FW_CTRL1_UC_DP_S);
+			  BIT(cpu_port) << QCA8K_GLOBAL_FW_CTRL1_IGMP_DP_S |
+			  BIT(cpu_port) << QCA8K_GLOBAL_FW_CTRL1_BC_DP_S |
+			  BIT(cpu_port) << QCA8K_GLOBAL_FW_CTRL1_MC_DP_S |
+			  BIT(cpu_port) << QCA8K_GLOBAL_FW_CTRL1_UC_DP_S);
 	if (ret)
 		return ret;
 
 	/* Setup connection between CPU port & user ports */
 	for (i = 0; i < QCA8K_NUM_PORTS; i++) {
 		/* CPU port gets connected to all user ports of the switch */
 		if (dsa_is_cpu_port(ds, i)) {
-			ret = qca8k_rmw(priv, QCA8K_PORT_LOOKUP_CTRL(QCA8K_CPU_PORT),
+			ret = qca8k_rmw(priv, QCA8K_PORT_LOOKUP_CTRL(cpu_port),
 					QCA8K_PORT_LOOKUP_MEMBER, dsa_user_ports(ds));
 			if (ret)
 				return ret;
@@ -1110,7 +1126,7 @@ qca8k_setup(struct dsa_switch *ds)
 
 			ret = qca8k_rmw(priv, QCA8K_PORT_LOOKUP_CTRL(i),
 					QCA8K_PORT_LOOKUP_MEMBER,
-					BIT(QCA8K_CPU_PORT));
+					BIT(cpu_port));
 			if (ret)
 				return ret;
 
@@ -1616,9 +1632,12 @@ static int
 qca8k_port_bridge_join(struct dsa_switch *ds, int port, struct net_device *br)
 {
 	struct qca8k_priv *priv = (struct qca8k_priv *)ds->priv;
-	int port_mask = BIT(QCA8K_CPU_PORT);
+	int port_mask, cpu_port;
 	int i, ret;
 
+	cpu_port = dsa_to_port(ds, port)->cpu_dp->index;
+	port_mask = BIT(cpu_port);
+
 	for (i = 1; i < QCA8K_NUM_PORTS; i++) {
 		if (dsa_to_port(ds, i)->bridge_dev != br)
 			continue;
@@ -1645,7 +1664,9 @@ static void
 qca8k_port_bridge_leave(struct dsa_switch *ds, int port, struct net_device *br)
 {
 	struct qca8k_priv *priv = (struct qca8k_priv *)ds->priv;
-	int i;
+	int cpu_port, i;
+
+	cpu_port = dsa_to_port(ds, port)->cpu_dp->index;
 
 	for (i = 1; i < QCA8K_NUM_PORTS; i++) {
 		if (dsa_to_port(ds, i)->bridge_dev != br)
@@ -1662,7 +1683,7 @@ qca8k_port_bridge_leave(struct dsa_switch *ds, int port, struct net_device *br)
 	 * this port
 	 */
 	qca8k_rmw(priv, QCA8K_PORT_LOOKUP_CTRL(port),
-		  QCA8K_PORT_LOOKUP_MEMBER, BIT(QCA8K_CPU_PORT));
+		  QCA8K_PORT_LOOKUP_MEMBER, BIT(cpu_port));
 }
 
 static int

drivers/net/dsa/qca8k.h

@@ -24,8 +24,6 @@
 
 #define QCA8K_NUM_FDB_RECORDS				2048
 
-#define QCA8K_CPU_PORT					0
-
 #define QCA8K_PORT_VID_DEF				1
 
 /* Global control registers */