While Register Level Programming (RLP) is not supported through the standard Applications Engineering support channels, I have provided you with the following suggestions.
Please see the Measurement Hardware Driver Development Kit Register Level Programming Architecture document, which I have provided a link to below, which states that the memory portion of osiBus, used for DMA operations, has not been implemented in the Linux version of osiBus at this point.
Measurement Hardware Driver Development Kit Register Level Programming Architecture
http://digital.ni.com/public.nsf/websearch/1C3988D7D33B925C86256C59007FB4B4?OpenDocument
Additionally, I would suggest that you post your question to the Driver Development Kit (DDK) forum on our Developer Zone,
in addition to the Counter/Timer and Multifunction DAQ sections, which you have already done.
Driver Development Kit (DDK) Forum
http://exchange.ni.com/servlet/ProcessRequest?RHIVEID=101&RPAGEID=8&RFORMNUMBER=3&RHIDETAG=TRUE&UCATEGORY_0=_321&UCATEGORY_S=0
Regards,
Justin Britten
Applications Engineer
National Instruments