Re: [Qemu-discuss] Coldfire 5282 Support

[William Mahoney]

> On Sep 5, 2017, at 4:37 PM, Peter Maydell <address@hidden> wrote:
> 
> On 5 September 2017 at 20:30, William Mahoney <address@hidden> wrote:
>> Thanks Thomas. One more question. Somewhere there must be a "what
>> parts to look for where” document. You know, a “If you are interested
>> in the device support for CPU XYZ, you look in the …XYZ directory” etc.
> 
> There's no document particularly. The rough structure is that
> devices live in hw/<category> (eg hw/char for UARTs), SoC
> models and board models live in hw/<architecture> (hw/m68k
> for m68k and coldfire), and the CPU emulation itself lives
> in target/<architecture>/.

OK let me take a day and do some poking at it. It should be OK to do a “make 
distclean” and rebuild just certain parts, I assume.

> 
>> 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, ...

> Do you need any/all of:
> * new CPU instructions ?

Nope. This is the good part, the 5282 and the 5208 use the exact same ISA.

> * other new CPU features ?
> * a new SoC ?
> * new devices (UART, timer, etc etc) that aren't in the
>   set we currently emulate ?

Yes. I have both User Guide PDFs from Moto and I can get a definitive list of 
exactly what is new. The 5282 is essentially “a 5208 with these additional 
goodies”.

> * a new board model that uses this new CPU ?
> or will what we have at the moment be all you need in
> one or more of those areas?

There is a 5282 eval board that I may be able to borrow from my past life. 

> 
> Depending on the answers it could be anywhere betwen 10
> days and 10 weeks…

Hey, I appreciate you narrowing it down! :-)

Bill


> 
> thanks
> -- PMM