Re: Deprecate the ppc405 boards in QEMU?

[BALATON Zoltan]

On Tue, 5 Oct 2021, Thomas Huth wrote:
> On 05/10/2021 10.07, Thomas Huth wrote:
> > On 05/10/2021 10.05, Alexey Kardashevskiy wrote:
> [...]
> > > What is so special about taihu?
> >
> > taihu is the other 405 board defined in hw/ppc/ppc405_boards.c (which I 
> > suggested to deprecate now)
>
> I've now also played with the u-boot sources a little bit, and with some bit 
> of tweaking, it's indeed possible to compile the old taihu board there. 
> However, it does not really work with QEMU anymore, it immediately triggers 
> an assert():
>
> $ qemu-system-ppc -M taihu -bios u-boot.bin -serial null -serial mon:stdio
> **
> ERROR:accel/tcg/tcg-accel-ops.c:79:tcg_handle_interrupt: assertion failed: 
> (qemu_mutex_iothread_locked())
> Aborted (core dumped)

Maybe it's similar to this: 2025fc6766ab25501e0041c564c44bb0f7389774 The 
helper_load_dcr() and helper_store_dcr() in target/ppc/timebase_helper.c 
seem to lock/unlock the iothread but I'm not sure if that's necessary. 
Also not sure why this does not happen with 460ex but that maybe uses 
different code.

> Going back to QEMU v2.3.0, I can see at least a little bit of output, but it 
> then also triggers an assert() during DRAM initialization:
>
> $ qemu-system-ppc -M taihu -bios u-boot.bin -serial null -serial mon:stdio
>
> Reset PowerPC core
>
> U-Boot 2014.10-rc2-00123-g461be2f96e-dirty (Oct 05 2021 - 10:02:56)
>
> CPU:   AMCC PowerPC 405EP Rev. B at 770 MHz (PLB=256 OPB=128 EBC=128)
>       I2C boot EEPROM disabled
>       Internal PCI arbiter enabled
>       16 KiB I-Cache 16 KiB D-Cache
> Board: Taihu - AMCC PPC405EP Evaluation Board
> I2C:   ready
> DRAM:  qemu-system-ppc: memory.c:1693: memory_region_del_subregion: Assertion 
> `subregion->container == mr' failed.
> Aborted (core dumped)
>
> Not sure if this ever worked in QEMU, maybe in the early 0.15 time, but that 
> version of QEMU also does not compile easily anymore on modern systems. So 
> I'm afraid, getting this into a workable shape again will take a lot of time. 
> At least I'll stop my efforts here now.

Do you have this u-boot binary somewhere just for others who want to try it?

Regards,
BALATON Zoltan