A system and method for using a data-only transfer protocol to store atomic cache line data in a local storage area is presented. A processing engine includes an atomic cache and a local storage. When the processing engine encounters a request to transfer cache line data from the atomic cache to the local storage (e.g., GETTLAR command), the processing engine utilizes a data-only transfer protocol to pass cache line data through the external bus node and back to the processing engine. The data-only transfer protocol comprises a data phase and does not include a prior command phase or snoop phase due to the fact that the processing engine communicates to the bus node instead of an entire computer system when the processing engine sends a data request to transfer data to itself.