Roger Carns wrote:

On 10/11/2010 3:18 PM, Gilles Chanteperdrix wrote:

Roger Carns wrote:

Does rt_io_get_region function be called from user space and does
it return a user space address and if so how is it return? Also
is there doc out there someplace on usage of this function.

rt_io_get_region is a user-space mapping of 
request_mem_regio/request_io_region. As such, yes, it may be called
from user-space. And no, it does not return address. What it
returns is a cookie that may be passed to rt_io_put_region to free
the used memory.

In order to map an MMIO region in user-space you should use
/dev/mem or use ioperm and inl/outl directly if you want to access
an I/O port. What rt_io_get_region does is to allow you to this
cleanly with regard to the rest of the system.

So, I open the /dev/mem and use the fd returned on the mmap call. But
how do I associate the region defined in the rt_io_get_region with
that fd?

The offset passed to mmap is the physical address which you want to map.

Please do not forget to CC the maling list.

great that was what I was going try first...thanks for your help