working with DSP of L138

we have a L138 LCDK Board. we could install arago-linux on it with matrix launcher.

the question is how to work with DSP via ARM.

i mean we have an application in ARM processor and we want to process some tasks on the DSP and return result to arm.

i don't have any idea about general overview about working with dsp in l138.

i don't know where i should start.

thanks for reply.