Re: destination offset

[Andreas B. <and...@mu...>]

On Wed, May 24, 2000 at 05:23:30PM +1000, Stephen Gibson wrote:
> 
> Hi this is probably another one of my dumb questions ...
> 
> If the root node receives a write request with a specific
> destination offset, does this mean that the data will be
> written to a specific memory location on the root node?

Although some 1394 chips can map a window of real memory into the
node's address space, all requests are manually interpreted by the
subsystem (except for CSR ROM reads on OHCI, as it seems).
 
> My application  sends a write request for a data block which specifies
> a return destination offset of 0x1000. Any address can be specified,
> but this just happens to be one that was snooped.
> 
> Can this address be registered in the root node using some method
> in libraw1394 or will I need to resort to the high level routines, such as
> used in ether1394.c
>    hpsb_register_addrspace        ?

You have to write a kernel module and use hpsb_register_addrspace().
Passing requests to user space would require some architectural change
in the subsystem.

-- 
 Andreas E. Bombe <and...@mu...>    DSA key 0x04880A44
http://home.pages.de/~andreas.bombe/    http://linux1394.sourceforge.net/