Hi Jiri.
>
> > Konrad / Daniel - any inputs on why LEON uses a different ASI?
> > As we uses this in head_32.S this is really annoying...
>
> It is not difficult to change the MMU reg ASI from 0x19 to 0x4
> (as defined in the SRMMU spec). However, all available LEON2/3/4
> chips in production uses 0x19 due to a decision take about 10
> years ago.
Then I consider that cast in stone :-(
We have leon boards out that uses ASI == 0x19.
What we really need is an implementation of head_32.S that transparently
handle the existing sun4m + sun4d boxes + the leon based boards.
If there is a way we reliably early on can decide if we run
one of the leon chips then we can always use a separate track in
head_32.S for the leon stuff.
Not that I like to do so - but this is better than the current
situation where we magically redefine ASI and thus are not
compatible with all paltforms in the same code.
I am having something in mind where we from head_32.S call
void sparc32_start_kernel(int cpu_model)
Then we can do the final preparations here before we call
start_kernel().
Today we transfer the cpu_model in the global variable
cputypval - and we may continue to do so too.
The point is that we should try to come up with
a head_32.S that handle but leon and non-leon
cpu's in the same file.
Then we can always handle the remaining issues using
instruction patching or ops structures etc.
If someone a Gaisler can look into head_32.S then
I would be happy to help with the rest.
Sam
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