[Bug 1000761] eCos support for MPC5xxx MCUs

[bugzilla-daemon at ecoscentric dot com]

http://bugs.ecos.sourceware.org/show_bug.cgi?id=1000761





--- Comment #13 from Jochen Gerster <Jochen.Gerster@freescale.com>  2009-07-06 21:52:20 ---
(In reply to comment #7)
> Would you be able to migrate your MPC5xxx contribution to use the updated
> PowerPC architectural HAL?

So concerning the migration to the updated PowerPC arch HAL we discovered two
major changes we like to discuss with you first...
a)We were able to switch to it for all e200z6 ports but there are some
constraints to do this also vor the mpc5510 (=e200z1) as here the core
exception handling has some difference compared to the higher e200 cores.
In detail, the e200z1 core only provides a IVOR base SPR and no further IVORx
offset SPRs. The offset between the exception vectors are fixed to 16bytes.
So the current BookE exception vector declaration in vector.s as to be changed.
We think the best solution is to have BookE exception vectors completely
independent from the old powerpc exception vectors. In the current
implementation BookE only enhance the existing exception vectors declaration.
Further should this booke exception handling support all e200 cores, means if
we make it work for e200z1 then it can also be used for all other e200 cores.

b)Further didn't we understand the usage of the ...NEED_VECTORS and
...COPY_VECTORS Macros in arch.inc hal_vectors_init for booke.
As if ....NEED_VECTORS isn't configured still the IVOR base SPR is written but
not the offsets, for us this didn't make sense as if I install exceptions I
completely do this and not partly?
We suggest to remove #if ...COPY_VECTORS and #if ...NEED_VECTORS in arch.inc
for booke, and instead differ only e200z1 and e200z_higher. Means for e200z1
only IVOR base SPR have to be written, and for all e200z_higher also the IVORx
offsets have to be written. But we would use therefore a different
configuration macro and not ...NEEDE_VECTORS

We appreciate your feedback...

best regards,
Jochen


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