Cyclic convolution between two matrices in matlab
Assuming that cconv2 does not exist, you can do it with the Fourier transform and multiplication:

A = some_MxN_matrix;
B = some_KxP_matrix;
Mfft = max(M,K);
Nfft = max(N,P);
C = ifft2( fft2(A,Mfft,Nfft) .* fft2(B,Mfft,Nfft) );


Hopefully the above helps.