I do not have code for that, but the authors of the paper described at https://assets.researchsquare.com/files/rs-884208/v1_covered.pdf?c=1656088168 must have it, as they simulated their calculations in MATLAB. You could ask them whether they would be willing to make the source code available.
https://github.com/Shenzhi-ZHANG/Massive-MIMO-Precoding as a code implementation but it is not obvious to me that it is cell-free.
Note:
My experience is that the authors of papers are seldom willing to bother sending source-code to undergraduate students, but that they are sometimes willing to make source-code available to professors.
