Running u-boot standalone hello_world on an image partition with qemu

[Simon Glass]

Hi Lists,

On Fri, 4 Nov 2022 at 04:26, Lists Nick Betteridge
<lists.nick.betteridge at gmail.com> wrote:
>
> Hi Simon,
>
> Thanks for getting back to me
>
> >>
> >> I'm developing on an ubuntu x86 machine, trying to run the u-boot
> >> hello_world standalone application which resides on an image |sd.img|
> >> which contains a partition
> >>
> >> I've compiled u-boot (|v2022.10|) with |qemu-x86_64_defconfig|
> >>
> >> I run qemu with "|qemu-system-x86_64 -m 1024 -nographic -bios u-boot.rom
> >> -drive format=raw,file=sd.img"|
> >>
> >> u-boot starts up, doesn't find a script, doesn't detect tftp, and awaits
> >> a command. If I type |"ext4ls ide 0:1|", I can clearly see
> >> hello_world.bin (|3932704 hello_world.bin|).
> >>
> >> When I do a |ext4load ide 0:1 0x40000 hello_world.bin| (in preparation
> >> for |go 40000 This is another test|), qemu/u-boot restarts.
> >>
> >> 0x40000 is the |CONFIG_STANDALONE_LOAD_ADDR| for x86.
> >>
> >> I have also tried making an image of hello_world |"mkimage -n "Hello
> >> stand alone" -A x86_64 -O u-boot -T standalone -C none -a 0x40000 -d
> >> hello_world.bin -v hello_world.img|" and tried to load the image into
> >> 0x40000 with the intention of using |bootm| in case of cache issues -
> >> qemu/u-boot still resets.
> >>
> >> Could anyone possibly point out the basic mistake I'm making?
> >
> > Is the app linked to start at that address. Could you try 'dcache off'
> > before the 'go'? Do you have a debugger?
> >
>
> The standalone Makefile sets up the start address at 0x40000
> (CONFIG_STANDALONE_LOAD_ADDR), so I'm assuming that hello_world.bin is
> correctly linked to that address.
>
> I'm unable to even try 'dcache off' before 'go' as the 'ext4load' at
> CONFIG_STANDALONE_LOAD_ADDR causes a restart.
>
> As I mentioned to Tom Rini, all I'm trying to do at the moment is
> develop a standalone program using u-boot and qemu on my x86 ubuntu
> machine and then target a platform (riscv or arm) at a later date.
>
> Thanks again for your reply

Does qemu have RAM at 0x40000? Can you use 'md' to check that region?
I am not sure why it is restarting when you load something there, but
that might be unrelated to U-Boot and more to do with QEMU?

Regards,
Simon