mlxsw: spectrum_buffers: Add ability to veto TC's configuration

Subsequent patches are going to need to veto changes in certain TCs'
binding and threshold configurations.

Add fields to the TC's struct that indicate if the TC can be bound to a
different pool and whether its threshold can change and enforce that.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -30,6 +30,8 @@ struct mlxsw_sp_sb_cm {
 	u32 max_buff;
 	u16 pool_index;
 	struct mlxsw_cp_sb_occ occ;
+	u8 freeze_pool:1,
+	   freeze_thresh:1;
 };
 
 #define MLXSW_SP_SB_INFI -1U
@@ -1059,6 +1061,7 @@ int mlxsw_sp_sb_tc_pool_bind_set(struct mlxsw_core_port *mlxsw_core_port,
 			mlxsw_core_port_driver_priv(mlxsw_core_port);
 	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
 	u8 local_port = mlxsw_sp_port->local_port;
+	const struct mlxsw_sp_sb_cm *cm;
 	u8 pg_buff = tc_index;
 	enum mlxsw_reg_sbxx_dir dir = (enum mlxsw_reg_sbxx_dir) pool_type;
 	u32 max_buff;
@@ -1069,6 +1072,21 @@ int mlxsw_sp_sb_tc_pool_bind_set(struct mlxsw_core_port *mlxsw_core_port,
 		return -EINVAL;
 	}
 
+	if (dir == MLXSW_REG_SBXX_DIR_INGRESS)
+		cm = &mlxsw_sp->sb_vals->cms_ingress[tc_index];
+	else
+		cm = &mlxsw_sp->sb_vals->cms_egress[tc_index];
+
+	if (cm->freeze_pool && cm->pool_index != pool_index) {
+		NL_SET_ERR_MSG_MOD(extack, "Binding this TC to a different pool is forbidden");
+		return -EINVAL;
+	}
+
+	if (cm->freeze_thresh && cm->max_buff != threshold) {
+		NL_SET_ERR_MSG_MOD(extack, "Changing this TC's threshold is forbidden");
+		return -EINVAL;
+	}
+
 	err = mlxsw_sp_sb_threshold_in(mlxsw_sp, pool_index,
 				       threshold, &max_buff, extack);
 	if (err)