Lyle, You have to traverse the assembly structure and search each component for CSYS and add them up in a Collection for the full assembly. See the section Assemblies and Components for sample code traverses the assembly structure.
RE: JLINK - get all the csys origins in the assembly?
In order to get all the cys in every item in the assembly then you will need to loop to each item in the assembly to collect all cys. There is not a method to collect all cys for each component in an assembly.