Re: [PATCH] hw/acpi: Set memory regions to native endian as a work around

[Paolo Bonzini]

On 3/7/23 16:21, BALATON Zoltan wrote:
> > I didn't even have an idea that Forth was involved, honestly, or how 
> > to write Forth code for this machine that I barely know exists. 😄
>
> It's supposed to be CHRP compatible which mandates OpenFirmware so it 
> should work about the same as similar IBM and Apple machines but those 
> are also kind of obscure. If you can describe what you want tested I can 
> try to make that a script and ask somebody to run it on real machine but 
> I'm not sure what to test.

For example:

- read the PMTIMER, check that it increases when read as little endian

- read individual bytes of the PMTIMER and check which increase faster


Also, since we've probably identified the EN and STS registers:

- write 0 to the supposed 16-bit EN register

- write 1 to the supposed 16-bit EN register

- check that it reads back as 1 (the STS register would not)

- read individual bytes of the 16-bit EN register and check which is the 
low and which is the high one

- write 0x100 to the supposed 16-bit EN register

- check that it reads back as 0x100

- read individual bytes of the 16-bit EN register and confirm that the 
one you identified as "low" now reads 0 and the one you identified as 
"high" now reads 1


Or:

- read the (supposed) 16-bit STS register

- wait for the STS register to be non-zero

- write the read value to the STS register

- read again and check that it's zero

- wait for the STS register to be non-zero

- read the individual bytes of the 16-bit STS register and check which 
is the low and which is the high one

- wait for the STS register to be non-zero

- for each individual byte of the STS register, write it back, and check 
that it now reads to zero

Part of this should already work in QEMU.

Paolo