We propose an efficient protocol to perform universal quantum control of an oscillator mode (e.g. cavity mode) off-resonantly coupled to an ancillary qubit. With an excitation number truncation, such a fully controllable oscillator mode can be used as a d-level system—-qudit. Alternatively, we show that d levels can be encoded using d well separated coherent states and the operations can be performed holonomically. We also show that with both encoding schemes the system state can be reconstructed using photon number counting. These schemes can be implemented using superconducting circuits.