[Qemu-devel] Port Qemu to another ARM platform

[Qemu-devel] Port Qemu to another ARM platform

[Christian Roepke]

Hi,

I consider to port qemu to another ARM platform so that I have a software
simulator for my microcontroller board. There is an ARM926EJ-S core on my board
which is backwards compatible from ARM7. Hence I must not port the cpu core
only the interrupt controller, timer, uart, ... I hope that such a software
simulator is good for testing my software/OS - I am currently porting the L4
micro-kernel (http://os.inf.tu-dresden.de/L4/) to my board.

Is there a documents available which decribes how to port qemu to another ARM
platform or something similar?

Kind regards,
Hans

--
 Hans Christian Röpke
 Network Administration

 Applied Data Security Group
 Ruhr-Universität Bochum, IC 4/42
 Universitätsstrasse 150
 44780 Bochum, Germany
 http://www.prosec.rub.de

[Qemu-devel] Port Qemu to another ARM platform

[Christian Roepke]

Hi,

I consider to port qemu to another ARM platform so that I have a software
simulator for my microcontroller board. There is an ARM926EJ-S core on my board
which is backwards compatible from ARM7. Hence I must not port the cpu core
only the interrupt controller, timer, uart, ... I hope that such a software
simulator is good for testing my software/OS - I am currently porting the L4
micro-kernel (http://os.inf.tu-dresden.de/L4/) to my board.

Is there a documents available which decribes how to port qemu to another ARM
platform or something similar?

Kind regards,
Hans

--
 Hans Christian Röpke
 Network Administration

 Applied Data Security Group
 Ruhr-Universität Bochum, IC 4/42
 Universitätsstrasse 150
 44780 Bochum, Germany
 http://www.prosec.rub.de

Re: [Qemu-devel] Port Qemu to another ARM platform

[Paul Brook]

On Tuesday 08 August 2006 16:04, Christian Roepke wrote:
> Hi,
>
> I consider to port qemu to another ARM platform so that I have a software
> simulator for my microcontroller board. There is an ARM926EJ-S core on my
> board which is backwards compatible from ARM7. Hence I must not port the
> cpu core only the interrupt controller, timer, uart, ... I hope that such a
> software simulator is good for testing my software/OS - I am currently
> porting the L4 micro-kernel (http://os.inf.tu-dresden.de/L4/) to my board.
>
> Is there a documents available which decribes how to port qemu to another
> ARM platform or something similar?

Not really. However qemu already supports a few different Arm boards, so 
looking at the source should tell you most of what you need to know.

Paul

Re: [Qemu-devel] Port Qemu to another ARM platform

[Christian Roepke]

Hello,

> > Hi,
> >
> > I consider to port qemu to another ARM platform so that I have a software
> > simulator for my microcontroller board. There is an ARM926EJ-S core on my
> > board which is backwards compatible from ARM7. Hence I must not port the
> > cpu core only the interrupt controller, timer, uart, ... I hope that such a
> > software simulator is good for testing my software/OS - I am currently
> > porting the L4 micro-kernel (http://os.inf.tu-dresden.de/L4/) to my board.
> >
> > Is there a documents available which decribes how to port qemu to another
> > ARM platform or something similar?
> 
> Not really. However qemu already supports a few different Arm boards, so 
> looking at the source should tell you most of what you need to know.

But the Integrator port is the only ARM926EJ-S port, right? Is everythink
platform specific implemented in ./hw/integratorcp.c ?

If my software works on qemu, does it work on a real Integrator board, too? Or
are there some differences?

Thanks,
Hans

Re: [Qemu-devel] Port Qemu to another ARM platform

[Paul Brook]

> > > Is there a documents available which decribes how to port qemu to
> > > another ARM platform or something similar?
> >
> > Not really. However qemu already supports a few different Arm boards, so
> > looking at the source should tell you most of what you need to know.
>
> But the Integrator port is the only ARM926EJ-S port, right? 

The versatile board also uses an Arm926 core (as well as sharing much of the 
device emulation).

> Is everythink platform specific implemented in ./hw/integratorcp.c ?

Yes. There's actually very little board specific code. Almost everything 
(including interrupt controllers) are implemented as independent devices, the 
board specific code just instantiates those devices.

> If my software works on qemu, does it work on a real Integrator board, too?
> Or are there some differences?

There are several bits of of hardware emulation missing (notably flash, MMC 
and AACI).

Partly as a side-effect of this there's no significant bootloaded on the 
emulated board. It knows how to load linux kernels (or I guess and PIC binary 
image), but that's about it.

Also note that qemu isn't even vaguely cycle accurate, and doesn't accurately 
model TLB or cache. It should be sufficient for most applications, but code 
that does sneaky hardware specific things (like assuming a particular TLB 
size or relying on cache/TLB lockdown for correct behavior) will break.

Other than that it should work just like real hardware. I'm sure there are 
bugs if you look hard enough, but that's a somewhat different issue.

Paul