FFT Accelerator - procedure for terminating an ongoing FFT computation

Please advise on the correct procedure for aborting an ongoing FFT computation. I have tried the following but the core hangs if there is an active acclerator DMA (as indicated in FFTDMASTAT register) at the time of termination.

1) r0=dm(FFTCTL1); r1=~(FFT_START|FFT_DMAEN); dm(FFTCTL1)=r0;

2)r0=dm(FFTCTL1); r1=~(FFT_EN|FFT_START|FFT_DMAEN);dm(FFTCTL1)=r0;

3)r0=FFT_RST; dm(FFTCTL1)=r0; nop;nop;nop;nop;

Thanks