how to programm the arduino UNO using simulink/matlab?

Hello evrybody;

I'm trying to connect arduino UNO with canbus shield in my project using simulink/matlab.

So, my question is : in which manner we have to programm the arduino :

1- by programming it in arduino IDE and then use simulink blocks to receive data ??

2- by programming it under simulink using Sfunction in matlab???

thankyou in advance.