Re: [Qemu-devel] Using QEMU for embedded systems

["J. Mayer" <l_indien@magic.fr>]

On Thu, 2005-02-17 at 08:33, Peter Korsgaard wrote:
> >>>>> "Waqqas" == Waqqas Jabbar <waqqas_jabbar@yahoo.com> writes:
>  Waqqas> I was thinking if qemu can emulate a complete PC, then it
>  Waqqas> might be a good canditate to use in embedded system
>  Waqqas> development to emulate a board. What do you think about it.
> 
> I have been playing a bit around with that as well. I have modified
> the PPC prep target to match one of our embedded systems (IBM405
> based).  
> 
> It's pretty basic, but I do get the first text out on the serial port
> ;) - I'll need to implement some 40x specific instructions to continue.

PPC 4xx support is planned. I already have a kernel emulation of 405
specific user-mode instructions, implemented like FP emulation. The goal
is to be able to test PPC405 executables on standard ones (ie on Mac
hw).
I can quite easily transpose this in qemu.

There's a lack of OEA specific instructions but most of them can be
implemented with no-op. TLB management must be added, it may be really
near the MIPS software TLB management (posted here a few days ago,
message ID <1108309390.3148.12.camel@rapid>).
DCR is quite like direct devices IOs, it should be quite easy to do
efficientl,y quite like IO in softmmu, using a table of callbacks for
read & writes, imho.

The big part missing is the hardware emulation of 4xx internal devices.
What is mandatory to boot is:
- external bus controller
- memory controller
- timers & watchdog
- interrupt controller
- some GPIOs control may be needed
- serial ports (which are not 16550 compatibles).
Some other special SPRs may also be needed...

I think most of the work to do is there, in hw emulation.
I have a lack of detailed documentation about PPC 401. So, some links
would be appreciated....
-- 
J. Mayer <l_indien@magic.fr>
Never organized