net: dsa: qca8k: add support for mirror mode

The switch supports mirror mode. Only one port can set as mirror port and
every other port can set to both ingress and egress mode. The mirror
port is disabled and reverted to normal operation once every port is
removed from sending packet to it.
Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/qca8k.c

@@ -2022,6 +2022,99 @@ qca8k_port_mdb_del(struct dsa_switch *ds, int port,
 	return qca8k_fdb_search_and_del(priv, BIT(port), addr, vid);
 }
 
+static int
+qca8k_port_mirror_add(struct dsa_switch *ds, int port,
+		      struct dsa_mall_mirror_tc_entry *mirror,
+		      bool ingress)
+{
+	struct qca8k_priv *priv = ds->priv;
+	int monitor_port, ret;
+	u32 reg, val;
+
+	/* Check for existent entry */
+	if ((ingress ? priv->mirror_rx : priv->mirror_tx) & BIT(port))
+		return -EEXIST;
+
+	ret = regmap_read(priv->regmap, QCA8K_REG_GLOBAL_FW_CTRL0, &val);
+	if (ret)
+		return ret;
+
+	/* QCA83xx can have only one port set to mirror mode.
+	 * Check that the correct port is requested and return error otherwise.
+	 * When no mirror port is set, the values is set to 0xF
+	 */
+	monitor_port = FIELD_GET(QCA8K_GLOBAL_FW_CTRL0_MIRROR_PORT_NUM, val);
+	if (monitor_port != 0xF && monitor_port != mirror->to_local_port)
+		return -EEXIST;
+
+	/* Set the monitor port */
+	val = FIELD_PREP(QCA8K_GLOBAL_FW_CTRL0_MIRROR_PORT_NUM,
+			 mirror->to_local_port);
+	ret = regmap_update_bits(priv->regmap, QCA8K_REG_GLOBAL_FW_CTRL0,
+				 QCA8K_GLOBAL_FW_CTRL0_MIRROR_PORT_NUM, val);
+	if (ret)
+		return ret;
+
+	if (ingress) {
+		reg = QCA8K_PORT_LOOKUP_CTRL(port);
+		val = QCA8K_PORT_LOOKUP_ING_MIRROR_EN;
+	} else {
+		reg = QCA8K_REG_PORT_HOL_CTRL1(port);
+		val = QCA8K_PORT_HOL_CTRL1_EG_MIRROR_EN;
+	}
+
+	ret = regmap_update_bits(priv->regmap, reg, val, val);
+	if (ret)
+		return ret;
+
+	/* Track mirror port for tx and rx to decide when the
+	 * mirror port has to be disabled.
+	 */
+	if (ingress)
+		priv->mirror_rx |= BIT(port);
+	else
+		priv->mirror_tx |= BIT(port);
+
+	return 0;
+}
+
+static void
+qca8k_port_mirror_del(struct dsa_switch *ds, int port,
+		      struct dsa_mall_mirror_tc_entry *mirror)
+{
+	struct qca8k_priv *priv = ds->priv;
+	u32 reg, val;
+	int ret;
+
+	if (mirror->ingress) {
+		reg = QCA8K_PORT_LOOKUP_CTRL(port);
+		val = QCA8K_PORT_LOOKUP_ING_MIRROR_EN;
+	} else {
+		reg = QCA8K_REG_PORT_HOL_CTRL1(port);
+		val = QCA8K_PORT_HOL_CTRL1_EG_MIRROR_EN;
+	}
+
+	ret = regmap_clear_bits(priv->regmap, reg, val);
+	if (ret)
+		goto err;
+
+	if (mirror->ingress)
+		priv->mirror_rx &= ~BIT(port);
+	else
+		priv->mirror_tx &= ~BIT(port);
+
+	/* No port set to send packet to mirror port. Disable mirror port */
+	if (!priv->mirror_rx && !priv->mirror_tx) {
+		val = FIELD_PREP(QCA8K_GLOBAL_FW_CTRL0_MIRROR_PORT_NUM, 0xF);
+		ret = regmap_update_bits(priv->regmap, QCA8K_REG_GLOBAL_FW_CTRL0,
+					 QCA8K_GLOBAL_FW_CTRL0_MIRROR_PORT_NUM, val);
+		if (ret)
+			goto err;
+	}
+err:
+	dev_err(priv->dev, "Failed to del mirror port from %d", port);
+}
+
 static int
 qca8k_port_vlan_filtering(struct dsa_switch *ds, int port, bool vlan_filtering,
 			  struct netlink_ext_ack *extack)
@@ -2132,6 +2225,8 @@ static const struct dsa_switch_ops qca8k_switch_ops = {
 	.port_fdb_dump		= qca8k_port_fdb_dump,
 	.port_mdb_add		= qca8k_port_mdb_add,
 	.port_mdb_del		= qca8k_port_mdb_del,
+	.port_mirror_add	= qca8k_port_mirror_add,
+	.port_mirror_del	= qca8k_port_mirror_del,
 	.port_vlan_filtering	= qca8k_port_vlan_filtering,
 	.port_vlan_add		= qca8k_port_vlan_add,
 	.port_vlan_del		= qca8k_port_vlan_del,

drivers/net/dsa/qca8k.h

@@ -180,6 +180,7 @@
 #define   QCA8K_ATU_AGE_TIME(x)				FIELD_PREP(QCA8K_ATU_AGE_TIME_MASK, (x))
 #define QCA8K_REG_GLOBAL_FW_CTRL0			0x620
 #define   QCA8K_GLOBAL_FW_CTRL0_CPU_PORT_EN		BIT(10)
+#define   QCA8K_GLOBAL_FW_CTRL0_MIRROR_PORT_NUM		GENMASK(7, 4)
 #define QCA8K_REG_GLOBAL_FW_CTRL1			0x624
 #define   QCA8K_GLOBAL_FW_CTRL1_IGMP_DP_MASK		GENMASK(30, 24)
 #define   QCA8K_GLOBAL_FW_CTRL1_BC_DP_MASK		GENMASK(22, 16)
@@ -201,6 +202,7 @@
 #define   QCA8K_PORT_LOOKUP_STATE_LEARNING		QCA8K_PORT_LOOKUP_STATE(0x3)
 #define   QCA8K_PORT_LOOKUP_STATE_FORWARD		QCA8K_PORT_LOOKUP_STATE(0x4)
 #define   QCA8K_PORT_LOOKUP_LEARN			BIT(20)
+#define   QCA8K_PORT_LOOKUP_ING_MIRROR_EN		BIT(25)
 
 #define QCA8K_REG_GLOBAL_FC_THRESH			0x800
 #define   QCA8K_GLOBAL_FC_GOL_XON_THRES_MASK		GENMASK(24, 16)
@@ -305,6 +307,8 @@ struct qca8k_ports_config {
 struct qca8k_priv {
 	u8 switch_id;
 	u8 switch_revision;
+	u8 mirror_rx;
+	u8 mirror_tx;
 	bool legacy_phy_port_mapping;
 	struct qca8k_ports_config ports_config;
 	struct regmap *regmap;