[uClinux-dev] Re: Porting m68k/nommu to a new board.

[Geert Uytterhoeven]

Added CCs.

Hi,
I'm building a custom machine based around a 68sec000 (Fully static 68ec000).
The "board" is a bunch of parts at the moment but I have written a workable
simulator for the machine which I am using as a testbed for testing things
like my custom video, DMA controller etc before creating the hardware versions
in VHDL.
I'm interested in getting mmu-less m68k linux (what used to be known as
uclinux I guess, seems to be known as m68k/nommu now) running on the simulator
and later on the real hardware.
from what I can tell the nommu m68k port is still active. But does it actually
work? All the details on similar hardware (like the older Palm pilots, Atari
machines) is pretty ancient, around 2.0. Does anyone have a machine running a
recent kernel? Were there issues getting it running?
I did a bit of digging in the source and doesn't look like it should be too
difficult to add the specifics for my machine.. I have a 16550 style UART
emulated for I/O so I don't need to write a framebuffer driver at the moment.
I'm open to any suggestions people have on how to approach this though.
Please CC me as I'm not subscribed.
Thanks,
Daniel
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Gr{oetje,eeting}s,

? ? ? ? ? ? ? ? ? ? ? ? Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
? ? ? ? ? ? ? ? ? ? ? ? ? ?? ?? -- Linus Torvalds

[Greg Ungerer]

Hi Daniel,

I'm building a custom machine based around a 68sec000 (Fully static 68ec000).
The "board" is a bunch of parts at the moment but I have written a workable
simulator for the machine which I am using as a testbed for testing things
like my custom video, DMA controller etc before creating the hardware versions
in VHDL.
I'm interested in getting mmu-less m68k linux (what used to be known as
uclinux I guess, seems to be known as m68k/nommu now) running on the simulator
and later on the real hardware.

uclinux is/was mmuless support. m68knommu used to be the arch name for
m68k without mmu support. I just use Linux now, it has all been in
mainline for so long now.

from what I can tell the nommu m68k port is still active. But does it actually
work? All the details on similar hardware (like the older Palm pilots, Atari
machines) is pretty ancient, around 2.0. Does anyone have a machine running a
recent kernel? Were there issues getting it running?

I run on ColdFire parts all the time. Right up to 3.2-rc5 :-)
It works great. But I don't have or regularly use any original m68k
core hardware. I occasionally compile for the 68328 target, so it
will compile, can't be sure if it still runs though.

I did a bit of digging in the source and doesn't look like it should be too
difficult to add the specifics for my machine.. I have a 16550 style UART
emulated for I/O so I don't need to write a framebuffer driver at the moment.
I'm open to any suggestions people have on how to approach this though.

With the m68k and m68knommu arch code now merged it shouldn't
be too hard to enable/configure all the pieces you have. Might take
a little hacking to make it work, but it should be close.

Regards
Greg


------------------------------------------------------------------------
Greg Ungerer -- Principal Engineer EMAIL: gerg at snapgear.com
SnapGear Group, McAfee PHONE: [phone]
8 Gardner Close, FAX: [phone]
Milton, QLD, 4064, Australia WEB: http://www.SnapGear.com

[Greg Ungerer]

Hi Daniel,

Sorry for not replying sooner. Too much work :(

No problem :-)

Post by Greg Ungerer
I run on ColdFire parts all the time. Right up to 3.2-rc5 :-)
It works great. But I don't have or regularly use any original m68k
core hardware. I occasionally compile for the 68328 target, so it
will compile, can't be sure if it still runs though.

I did a bit of poking around, I couldn't get the 68328 target to build.. I was
going to have a play with it in xcopilot. It complains about some linker
section missing .. but I started hacking it up anyway.. at the moment m68328
depends on m68000 which in turn causes the 68328 platform stuff to build.
So I worked that a little so that 68000 is its own target that builds with
some minimal startup code (so I can dump the resulting image into my emulator
and see how far it gets.. I have a gdbserver in my emulator so I can fully see
whats happening). I haven't managed to get an image out of it yet.. but I will
have another go at the weekend.

Sounds good. Keep us posted on how you go.

I'm going to get an old palm pilot off of ebay and see if I can get the 68328
target running too.

Yeah, would be really nice to know what state the 68328 code is in.

I will compile it again too, and see if anything is obviously broken at
the moment.

Regards
Greg


------------------------------------------------------------------------
Greg Ungerer -- Principal Engineer EMAIL: gerg at snapgear.com
SnapGear Group, McAfee PHONE: [phone]
8 Gardner Close, FAX: [phone]
Milton, QLD, 4064, Australia WEB: http://www.SnapGear.com

[Greg Ungerer]

Hi Daniel,

Sorry for not replying sooner. Too much work :(

Post by Greg Ungerer
I run on ColdFire parts all the time. Right up to 3.2-rc5 :-)
It works great. But I don't have or regularly use any original m68k
core hardware. I occasionally compile for the 68328 target, so it
will compile, can't be sure if it still runs though.

I did a bit of poking around, I couldn't get the 68328 target to build.. I was
going to have a play with it in xcopilot. It complains about some linker

Yep, a couple of issues when building for the Palm/Pilot.
I just sent a couple of patches to m68k-linux that fix the main
problems. You will also want to disable CONFIG_FW_LOADER if you
have that enabled.

After that I can compile it all the way (I am building on 3.2-rc6).
No idea if it works though.

Regards
Greg



------------------------------------------------------------------------
Greg Ungerer -- Principal Engineer EMAIL: gerg at snapgear.com
SnapGear Group, McAfee PHONE: [phone]
8 Gardner Close FAX: [phone]
Milton, QLD, 4064, Australia WEB: http://www.SnapGear.com