Re: [Qemu-discuss] Coldfire 5282 Support

[William Mahoney]

I thought I would look at the -bios first and I had some time this afternoon. 
If you’re the right age group you will understand when I say "YOU ARE IN A MAZE 
OF TWISTY LITTLE PASSAGES, ALL ALIKE”.

"digic_load_rom()" knows the filename via an extern “bios_name” which is at 
“include/sysemu/sysemu.h” but really lives in “vl.c”. It is set based on 
“machine_ops” that comes from “qemu_get_machine_opts()” which in turn comes 
from “emu_find_opts_singleton()” which is in "util/qemu-config.c”…

Shortcut time. Presumably there is a way to specify some command line switch, 
described as “-bios”, and have the filename end up at “digit_load_rom()”. But I 
don’t see the direct path, or a header with all the options listed for the 
specific machine, or… Can you walk me through how a “-bios” command line switch 
is actually supposed to appear (it doesn’t on qemu-system-arm)?

Or should I be installing Oxygen?  :-)

On Sep 6, 2017, at 12:56 AM, Thomas Huth 
<address@hidden<mailto:address@hidden>> wrote:

On 06.09.2017 00:04, William Mahoney wrote:

On Sep 5, 2017, at 4:37 PM, Peter Maydell 
<address@hidden<mailto:address@hidden>> wrote:

On 5 September 2017 at 20:30, William Mahoney 
<address@hidden<mailto:address@hidden>> wrote:
[...]
I’d like to find this and/or anything else to clue me in before
starting as to the level of difficulty to add 5282. I mean, I
have decades of “C” background, I know the 5282 well, but am I
going to be 10 days or 10 weeks?

This depends a lot on how different the 5282 is from what
we currently support (5206 and 5208, from the looks of things).

It’s like a 5208 but with additional on-chip I/O. Some of it is simple, like 
the UARTs are identical I think. Some parts are new, on-chip FLASH and SRAM, 
CAN bus, ...

That's good, so you might be able to simply start with the 5208 core.

I suggest that you start with making a copy of hw/m68k/mcf5208.c and
then see what you need to modify there. To support the "-bios" parameter
of QEMU, do a "grep -r bios_name hw/" to see how it is handled in the
other boards (e.g. something like the digic_load_rom() function in
hw/arm/digic_boards.c).

Thomas