1. A hybrid data storage device comprising: a hard disc drive (HDD) controller circuit coupled to non-volatile rotatable storage media; a solid state drive (SSD) controller circuit coupled to non-volatile solid state memory; a local volatile memory having an HDD partition accessible by the HDD controller circuit and not accessible by the SSD controller circuit and having an SSD partition accessible by the SSD controller circuit and not accessible by the HDD controller circuit; and a top level controller circuit coupled to the respective HDD and SSD controller circuits and to the respective HDD and SSD partitions, the top level controller circuit configured to perform a cleaning operation to transfer a data set from the non-volatile solid state memory to the rotatable storage media by issuing a read command to the SSD controller circuit to retrieve the data set to the SSD partition, transferring the data set from the SSD partition to the HDD partition, and issuing a write command to the HDD controller circuit to write the data set from the HDD partition to the rotatable storage media.