[driver-discuss] mapping DMA memory to userspace (again)

[Mark Johnson]

Joachim Worringen wrote:
> The problem of mapping memory from ddi_dma_mem_alloc() to userspace 
> seems to be persistent (see 
> http://forum.java.sun.com/thread.jspa?threadID=5077776 or 
> http://forum.java.sun.com/thread.jspa?threadID=5077633) as something 
> like devmap_dmamem_setup() is missing next to the existing 
> devmap_umem_setup() and devmap_devmem_setup().
> 
> The problem with the current DDI (I use SXCE 68, but the driver should 
> run on Solaris >= 10) is the missing umem-cookie to feed into 
> devmap_umem_setup(). For now, I have chosen the work-around (call it 
> hack) to build this cookie myself by assigning the kvaddr, size and type 
> myself. This seems to work, but surely isn't pretty.
> 
> - Is there a clean workaround for this problem? How are others solving 
> this problem?

No, this is the cleanest workaround available today.


> - Is there a RFE for this problem, or even a targeted solution?

Yes...
   http://bugs.opensolaris.org/view_bug.do?bug_id=6358545

The code has been done for a while.. I just need to do
the documentation and ARC work...



MRJ




-- 
Mark Johnson <mark.johnson at sun.com>
Sun Microsystems, Inc.
(781) 442-0869