Create permanent mapping from PCI bus to region of physical memory

[Howard, Marc]

Hi,

I'm working on a PPC440GX based board in which a PCI based peripheral
communicates with the host via a shared region of processor memory.  The
peripheral will read and write this region autonomously.  Because of
this I need a fixed mapping FROM the PCI bus TO system memory.

It's easy enough to rope off the top 16 MB or so of system physical
memory by lying to linux in the boot arguments.  What I can't seem find
is a system call to use to create a fixed, permanent mapping of PPC
memory as seen from the PCI bus.

Has anyone out there done this and could share a code snippet with me?

Thanks,

Marc W. Howard