Modify simulink model to run on R' Pi with adjacent Mega 2560 for I/O fetch

Hello Mathworks, I have created a Simulink model for a robot that requires multiple I/O ports to fetch and send digital and analog signals. Therefore, I'm using Arduino Mega 2560 for the task. However, as the model has some complicated mathematical functions and the generated code is quite lengthy for any microcontroller from Atmel, I am using my PC to do the calculations and MCU to handle I/O's in parallel (running on target hardware instead of deploying to hardware). After I have tuned the parameters and verified the working of the model, I intend to run it independent of my PC and execute the calculations on a Raspberry Pi 2 B. That being said, what modifications do I have to make into model configurations to deploy the model on a Pi, which has to gather inputs/ provide outputs using an Arduino while running the code in itself. Please respond fast.