OMAP L138 ARM to PRU0 software triggered interrupt

Hi,

Is there any way to trigger an interrupt from the ARM processor to PRU0 using software (rather than a peripheral or pin based mechanism)? 

This is intended for waking the PRU0 up from the SLP command but also for message passing between the ARM and PRU0.

I've looked at the documentation in http://processors.wiki.ti.com/index.php/PRU_Interrupt_Controller but from what I can tell it all looks like hardware triggered interrupts.

Thanks

Nigel