Re: [RFC PULL] remove arch/h8300

From: Greg Ungerer
Date: Sat Apr 09 2022 - 00:19:04 EST



On 9/4/22 11:59, Finn Thain wrote:
On Fri, 8 Apr 2022, Rob Landley wrote:

On 4/5/22 08:07, Greg Ungerer wrote:
On 5/4/22 13:23, Daniel Palmer wrote:
On Mon, 4 Apr 2022 at 22:42, Greg Ungerer <gerg@xxxxxxxxxxxxxx> wrote:
But we could consider the Dragonball support for removal. I keep it
compiling, but I don't use it and can't test that it actually works.
Not sure that it has been used for a very long time now. And I
didn't even realize but its serial driver (68328serial.c) was
removed in 2015. No one seems too have noticed and complained.

I noticed this and I am working on fixing it up for a new Dragonball
homebrew machine. I'm trying to add a 68000 machine to QEMU to make
the development easier because I'm currently waiting an hour or more
for a kernel to load over serial. It might be a few months.

I've been booting Linux on qemu-system-m68k -M q800 for a couple years
now? (The CROSS=m68k target of mkroot in toybox?)

# cat /proc/cpuinfo
CPU: 68040
MMU: 68040
FPU: 68040
Clocking: 1261.9MHz
BogoMips: 841.31
Calibration: 4206592 loops

It certainly THINKS it's got m68000...


Most 68040 processor variants have a built-in MMU and the m68k "nommu"
Linux port doesn't support them. The nommu port covers processors like
68000, Dragonball etc. whereas the m68k "mmu" port covers 680x0 where x is
one of 2,3,4,6 with MMU.

$ qemu-system-m68k -cpu ?
cfv4e
m5206
m5208
m68000
m68010
m68020
m68030
m68040
m68060
any

(I'd love to get an m68k nommu system working but never sat down and
worked out a kernel .config qemu agreed to run, plus compiler and libc.
Musl added m68k support but I dunno if that includes coldfire?)


I could never figure out how to boot a coldfire machine in qemu either.
There was no documentation about that back when I attempted it but maybe
things have improved since.

FWIW this will do it:

qemu-system-m68k -nographic -machine mcf5208evb -kernel vmlinux

That will boot an m5208evb_defconfig generated vmlinux.
But you will need a user space to get a full boot to login/shell.

Regards
Greg