cx88 WRITERM instruction

Hi,

I'm trying to add precise timestamps to the cx88 driver but I somehow fail to use the WRITERM instruction correctly. Has anyone ever successfully used that RISC instruction? Is there a bit that needs to be flipped to actually make it perform writes to the PCI bus?

I know it is executed because I get a RISC_RD_BERR_INT if I replace the third word with junk but no matter what I do the target memory stays untouched (yes, it is coherent memory and I use the DMA address).

Thanks,

Daniel