NetBSD on Motorola PowerStack II and IBM RS/6000 B50

Hi.

I ported NetBSD to the Motorola PowerStack II during the last months.
The PowerStack II is a 300 MHz PPC604e PReP machine with OpenFirmWare. 
(The OFW doesn't supply Residual Data, so port-prep can't run on it.)

Butattachments / bus_space(9) is working and the kernel reaches the
point where it wants to mount the root-FS or tries to scan the SCSI
bus. This does not work due to non working PCI DMA. I am using the 
same generic PPC PCI DMA code that port-prep uses und it woks on 
PReP machines. (My development machine is PReP, a IBM RS/6000 43P-100.) 
I am at a dead end here, as I don't know how to debug this. Beyond the 
DMA issus, I am sure that the Interrupt handling code needs work. But 
it should work enough to get to single user or at least beyond the 
SCSI bus scan. 

If someone else wants to play around with this stuff:
http://www.unixag-kl.fh-kl.de/~jkunz/tmp/ofwboot.elf.gz
http://www.unixag-kl.fh-kl.de/~jkunz/tmp/netbsd.gz
http://www.unixag-kl.fh-kl.de/~jkunz/tmp/ofppc.tar.gz
The last is my complete src/sys/arch/ofppc from a NetBSD-1.6 source tree.

Also: This code has initial support for the IBM RS/6000 B50, a CHRP/RPA
machine based on a 375 MHz PPC604e, Motorola MPC106 and an OpenPic. 

The OFW of this machine seams to be broken in some ways. If I "load net"
the bootloader it terminates with an error. tcpdump indicates that the
machine is trying to load more data via TFTP then there is available. (?)
But if I start the bootloader with "go" it runs just fine. Real strange 
is the bootloader. The same bootloader works well on the PowerStack II