[Buildroot] Persistent U-Boot environment variables under QEMU

[Buildroot] Persistent U-Boot environment variables under QEMU

[Jim Thomas]

I am experimenting with Buildroot under QEMU, using buildroot-2009.11 and buildroot-2010.02-rc1.

So far, so good.  I can boot a Linux kernel and RFS built by Buildroot under QEMU (versatilepb) where the RFS is exported via NFS.

QEMU includes a boot loader, so U-Boot is not needed.  But I use U-Boot with real ARM hardware, so I would like to experiment with U-Boot under QEMU, adding DHCP and TFTP to the mix.

With real hardware, the U-Boot environment variables are persistent in flash memory.

Is there a way to simulate this with QEMU?  I would not go to the trouble to manually enter the U-Boot environment variables each time I boot under QEMU, but if there is a persistence mechanism available then including U-Boot might be practical.

Thanks.

Jim



      
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.busybox.net/pipermail/buildroot/attachments/20100213/f1ccaebb/attachment-0001.htm>

[Buildroot] Persistent U-Boot environment variables under QEMU

[Thomas Petazzoni]

Hello,o

On Sat, 13 Feb 2010 13:51:26 -0800 (PST)
Jim Thomas <jimthomasembedded@yahoo.com> wrote:

> With real hardware, the U-Boot environment variables are persistent
> in flash memory.
> 
> Is there a way to simulate this with QEMU?  I would not go to the
> trouble to manually enter the U-Boot environment variables each time
> I boot under QEMU, but if there is a persistence mechanism available
> then including U-Boot might be practical.

Qemu can emulate flash memory, so U-Boot can be used "normally". In
2008, I managed to get U-Boot working on the versatilepb board
emulation of Qemu, with few changes to Qemu and U-Boot. See
http://thomas.enix.org/Blog-20081002153859-Technologie for details. The
three first patches have been merged into Qemu since then, but the last
(and most important) patch was never merged.

Cheers,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com