IWR6843: Using HWA (DSP) Functions from the MSS, without passing it to DSS

1) How can we pass data from MSS to the HWA hardware accelerator? We have some data coming in via SPI on MSS and we need to run FFT on that data, and we think the HWA will do great on this. Any thoughts? 

2) Is there any benchmark on how fast HWA run common DSP functions like FFT, etc?   

Thanks.