mlxsw: Add trap group for control packets

Previously, we trapped flooded and control packets using the same trap
group. This can cause flooded packets to overflow the PCI bus and
prevent control packets (e.g. STP, LACP) from getting to the CPU.

Solve this by splitting the RX trap group to RX and control, which allows
us to configure a policer on the first, thereby preventing it from
overflowing the PCI bus.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/reg.h

@@ -1029,8 +1029,11 @@ MLXSW_ITEM32(reg, htgt, swid, 0x00, 24, 8);
  */
 MLXSW_ITEM32(reg, htgt, type, 0x00, 8, 4);
 
-#define MLXSW_REG_HTGT_TRAP_GROUP_EMAD	0x0
-#define MLXSW_REG_HTGT_TRAP_GROUP_RX	0x1
+enum mlxsw_reg_htgt_trap_group {
+	MLXSW_REG_HTGT_TRAP_GROUP_EMAD,
+	MLXSW_REG_HTGT_TRAP_GROUP_RX,
+	MLXSW_REG_HTGT_TRAP_GROUP_CTRL,
+};
 
 /* reg_htgt_trap_group
  * Trap group number. User defined number specifying which trap groups
@@ -1097,6 +1100,7 @@ MLXSW_ITEM32(reg, htgt, local_path_cpu_tclass, 0x10, 16, 6);
 
 #define MLXSW_REG_HTGT_LOCAL_PATH_RDQ_EMAD	0x15
 #define MLXSW_REG_HTGT_LOCAL_PATH_RDQ_RX	0x14
+#define MLXSW_REG_HTGT_LOCAL_PATH_RDQ_CTRL	0x13
 
 /* reg_htgt_local_path_rdq
  * Receive descriptor queue (RDQ) to use for the trap group.
@@ -1104,21 +1108,29 @@ MLXSW_ITEM32(reg, htgt, local_path_cpu_tclass, 0x10, 16, 6);
  */
 MLXSW_ITEM32(reg, htgt, local_path_rdq, 0x10, 0, 6);
 
-static inline void mlxsw_reg_htgt_pack(char *payload, u8 trap_group)
+static inline void mlxsw_reg_htgt_pack(char *payload,
+				       enum mlxsw_reg_htgt_trap_group group)
 {
 	u8 swid, rdq;
 
 	MLXSW_REG_ZERO(htgt, payload);
-	if (MLXSW_REG_HTGT_TRAP_GROUP_EMAD == trap_group) {
+	switch (group) {
+	case MLXSW_REG_HTGT_TRAP_GROUP_EMAD:
 		swid = MLXSW_PORT_SWID_ALL_SWIDS;
 		rdq = MLXSW_REG_HTGT_LOCAL_PATH_RDQ_EMAD;
-	} else {
+		break;
+	case MLXSW_REG_HTGT_TRAP_GROUP_RX:
 		swid = 0;
 		rdq = MLXSW_REG_HTGT_LOCAL_PATH_RDQ_RX;
+		break;
+	case MLXSW_REG_HTGT_TRAP_GROUP_CTRL:
+		swid = 0;
+		rdq = MLXSW_REG_HTGT_LOCAL_PATH_RDQ_CTRL;
+		break;
 	}
 	mlxsw_reg_htgt_swid_set(payload, swid);
 	mlxsw_reg_htgt_type_set(payload, MLXSW_REG_HTGT_PATH_TYPE_LOCAL);
-	mlxsw_reg_htgt_trap_group_set(payload, trap_group);
+	mlxsw_reg_htgt_trap_group_set(payload, group);
 	mlxsw_reg_htgt_pide_set(payload, MLXSW_REG_HTGT_POLICER_DISABLE);
 	mlxsw_reg_htgt_pid_set(payload, 0);
 	mlxsw_reg_htgt_mirror_action_set(payload, MLXSW_REG_HTGT_TRAP_TO_CPU);
@@ -1211,7 +1223,7 @@ MLXSW_ITEM32(reg, hpkt, ctrl, 0x04, 16, 2);
 
 static inline void mlxsw_reg_hpkt_pack(char *payload, u8 action, u16 trap_id)
 {
-	u8 trap_group;
+	enum mlxsw_reg_htgt_trap_group trap_group;
 
 	MLXSW_REG_ZERO(hpkt, payload);
 	mlxsw_reg_hpkt_ack_set(payload, MLXSW_REG_HPKT_ACK_NOT_REQUIRED);

drivers/net/ethernet/mellanox/mlxsw/switchx2.c

@@ -1313,6 +1313,11 @@ static int mlxsw_sx_traps_init(struct mlxsw_sx *mlxsw_sx)
 	if (err)
 		return err;
 
+	mlxsw_reg_htgt_pack(htgt_pl, MLXSW_REG_HTGT_TRAP_GROUP_CTRL);
+	err = mlxsw_reg_write(mlxsw_sx->core, MLXSW_REG(htgt), htgt_pl);
+	if (err)
+		return err;
+
 	for (i = 0; i < ARRAY_SIZE(mlxsw_sx_rx_listener); i++) {
 		err = mlxsw_core_rx_listener_register(mlxsw_sx->core,
 						      &mlxsw_sx_rx_listener[i],