Re: [PATCH v3 0/8] dp8393x: fixes and improvements

[Finn Thain]

On Sun, 11 Jul 2021, Philippe Mathieu-Daudé wrote:

> 
> > If I'm right that the big_endian flag should go away, commit 
> > b1600ff195 ("hw/mips/jazz: specify correct endian for dp8393x device") 
> > has already taken mainline in the wrong direction and amounts to 
> > churn.
> 
> We might figure out with a BE guest image, the remove the endian flag.

Yes, it's hard to make progress without a BE guest. However, for testing 
dp8393x we probably don't need a disk image. I think we only need working 
firmware, since the RISC/os firmware appears to implement BOOTP and TFTP 
and appears to contain a SONIC driver.

This page discusses using the "MIPS Monitor" firmware on a Mips Magnum 
3000 machine to netboot NetBSD/mipsco: 
https://www.ludd.ltu.se/~ragge/htdocs/Ports/mipsco/install.html

Note that the firmware banner message looks like this:
Rx3230 MIPS Monitor: Version 5.43 OPT Mon May 13 17:31:12 PDT 1991 root 

It appears that there may be a similar firmware for MIPS Magnum at, 
https://gunkies.org/wiki/Installing_Windows_NT_4.0_on_Qemu(MIPS)

(I suppose this is the firmware floppy that was once found at ftp.sgi.com, 
after SGI acquired MIPS?)

The file RISCOS.RAW found in SETUP.ZIP appears to contain various string 
constants, both LE and BE, including:

$ swap64 < RISCOS.RAW |strings |egrep "Version|MIPS|Rx|Monitor"
...
Version 5.60 OPT-EB Wed Jun 17 11:23:28 PDT 1992 root
MIPS
Rx4230
%s %s Monitor: %s
...

This looks like the same banner, only for a different machine (as you'd 
expect). Unfortunately, nothing happened when I tried to boot that 
firmware:

$ ln -s RISCOS.RAW mips_bios.bin 
$ qemu-system-mips64 -M magnum -L . -global ds1225y.filename=mips-nvram -serial 
mon:stdio -serial null -nic bridge,model=dp83932,mac=00:00:00:aa:bb:cc

I don't know enough about this platform or about QEMU to go much further 
with this so I hope that others will be able to help.

I did find this link, which talks a little about the early boot code.
https://web.archive.org/web/20180823065803/http://www.sensi.org/~alec/mips/mips-history.html