[Qemu-devel] Using QEMU for embedded systems

[Qemu-devel] Using QEMU for embedded systems

[Waqqas Jabbar]

Hi

First of all, i will like to share my appreciation
about the project. Some good work you are doing here
:)

I was thinking if qemu can emulate a complete PC, then
it might be a good canditate to use in embedded system
development to emulate a board. What do you think
about it.

Advantages of this would be
1) Testing embedded software before the board is
actually developed
2) Testing different configuration


Thanks in advance

goto



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

[Mike Swanson]

Well, embedded devices are usually very different from each other, so
new code would have to be made for each device. I have nothing against
this, but I don't think it should be part of QEMU itself, but just
made by the people needing this functionality.


On Wed, 16 Feb 2005 06:38:05 -0800 (PST), Waqqas Jabbar
<waqqas_jabbar@yahoo.com> wrote:
> Hi
> 
> First of all, i will like to share my appreciation
> about the project. Some good work you are doing here
> :)
> 
> I was thinking if qemu can emulate a complete PC, then
> it might be a good canditate to use in embedded system
> development to emulate a board. What do you think
> about it.
> 
> Advantages of this would be
> 1) Testing embedded software before the board is
> actually developed
> 2) Testing different configuration
> 
> Thanks in advance
> 
> goto
> 
> __________________________________
> Do you Yahoo!?
> Take Yahoo! Mail with you! Get it on your mobile phone.
> http://mobile.yahoo.com/maildemo
> 
> _______________________________________________
> Qemu-devel mailing list
> Qemu-devel@nongnu.org
> http://lists.nongnu.org/mailman/listinfo/qemu-devel
>

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

[Peter Korsgaard]

>>>>> "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.

-- 
Bye, Peter Korsgaard

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

[Waqqas Jabbar]

The bare basic needed for an embedded system is to
emulate the following devices
1) one serial port
2) flash
3) ram

an aditional network card is also good (for tftp and
nfs mounted kernel and/or root filesystem). The main
difference between different board is the address
where these devices are mapped. 

The only thing missing in qemu is the flash device
support. how did u handled it? 

The size and memory location of these devices can be
set thru a configuration file or as command-line
parameter.

Did the new instructions that you added were required
to boot linux on your board or was it required by the
software you are developing on that board?

waqqas

--- Peter Korsgaard <jacmet@sunsite.dk> 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.
> 
> -- 
> Bye, Peter Korsgaard
> 
> 
> _______________________________________________
> Qemu-devel mailing list
> Qemu-devel@nongnu.org
> http://lists.nongnu.org/mailman/listinfo/qemu-devel
> 


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

[J. Mayer]

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

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

[Thayne Harbaugh]

On Thu, 2005-02-17 at 15:40 +0100, J. Mayer wrote:
> On Thu, 2005-02-17 at 08:33, Peter Korsgaard wrote:

> > 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.

I am *very* interested in PPC405.  I have resources to help develop this
and a group that can do testing.  Please let me know what your plans are
and how I might assist.

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

[Peter Korsgaard]

>>>>> "Waqqas" == Waqqas Jabbar <waqqas_jabbar@yahoo.com> writes:

 Waqqas> an aditional network card is also good (for tftp and nfs
 Waqqas> mounted kernel and/or root filesystem). The main difference
 Waqqas> between different board is the address where these devices
 Waqqas> are mapped.

 Waqqas> The only thing missing in qemu is the flash device
 Waqqas> support. how did u handled it?

The work I did was for booting eCos, not Linux.

I hacked the BIOS support to load my bootloader - I didn't implement
any flash emulation (yet).

 Waqqas> Did the new instructions that you added were required to boot
 Waqqas> linux on your board or was it required by the software you
 Waqqas> are developing on that board?

It was required by eCos.

-- 
Bye, Peter Korsgaard