Re: [Qemu-devel] Running linux on qemu omap

[Corentin Labbe]

On Wed, May 22, 2019 at 02:23:23AM +0300, Aaro Koskinen wrote:
> Hi,
> 
> On Mon, May 20, 2019 at 09:05:33PM +0200, Corentin Labbe wrote:
> > Hello
> > 
> > I am working on adding a maximum set of qemu machine on kernelCI.
> 
> That's cool.
> 
> > For OMAP, five machine exists and I fail to boot any of them.
> 
> Which machines?
> 
> > The maximum I can get with omap1_defconfig is
> > qemu-system-arm -kernel zImage -nographic -machine cheetah -append 
> > 'root=/dev/ram0 console=ttyO0'
> > Uncompressing Linux... done, booting the kernel.
> > then nothing more.
> 
> It's known that omap1_defconfig doesn't work well for QEMU or
> "multi-board" usage. Perhaps the kernel size is now just too big?
> I'm using a custom config for every OMAP1 board anyway...
> 
> > Does someone have a working config+version to share ?
> 
> I have used the below config for OMAP1 SX1 board (the only one I got
> working with QEMU). Unfortunately the functionality is quite limited,
> but it still allows to run e.g. GCC bootstrap & testsuite, that is rare
> nowadays for armv4t.
> 
> I'm using the following command line with qemu-system-arm 3.1.0:
> 
>         -M sx1 \
>         -kernel "sx1-zImage" \
>         -nographic \
>         -drive file="sx1-mmc",if=sd,format=raw \
>         -no-reboot
> 
> This should work with v5.1 kernel.
> 
> I'm also interested to run other OMAP kernels under QEMU, e.g. cheetah
> (the real device, Palm TE works OK with the current mainline), and it
> would be interesting to know why QEMU/kernel has regressed...
> 

Thanks, with your config as starting point, I was able to boot both sx1 and 
cheetah

So I now use the omap1_defconfig and the only trick is to disable 
CONFIG_CPU_DCACHE_WRITETHROUGH.
I need also to disable CONFIG_FB for cheetah to works.

Regards