Merging ppc32 and ppc64

[Kumar Gala]

On Aug 9, 2005, at 11:21 AM, Tom Rini wrote:

> On Tue, Aug 09, 2005 at 10:01:05AM -0500, Kumar Gala wrote:
>
>>> I think you are both right, just using different terminology. The
>>> running kernel uses its own representation of the device tree, which
>>> is neither the flattened stuff nor using the OF interfaces. The
>>> conversion from OF to the flattened tree is done by the kernel
>>>
> itself.
>
>>>
>>>      Apple OF  \
>>>          SLOF   \
>>>       pSeries    |-1- prom_init------,
>>>          PIBS   /                     \
>>>           ...  /                       \
>>>                                         \
>>>       other    -----------------------------2--
>>> unflatten_device_tree--3--
>>>   boot loader                              /
>>>                                           /
>>>       iSeries  ----------- early_setup---`
>>>
>>> All "regular" machines enter in the traditional prom_init path (1)
>>> from Open Firmware. The embedded machines that are too memory
>>> constraint
>>> to use SLOF have a flattened device tree in their boot loader and  
>>> the
>>> legacy iSeries boxes can fake the device tree in their
>>> iSeries_early_setup
>>> function. The main entry point (2) is entered by all machines when
>>>
> the
>
>>> flattened device tree is there and the kernel builds its tree
>>> representation
>>> for run time (3).
>>>
>>
>> I guess my point is that in the "new" powerpc arch doing steps 1 & 3
>> should no longer be part of the kernel proper.  The should be handled
>>
>
>
>> by boot wrappers of some form.  I know Ben tool care to ensure that
>> prom_init was isolated from kernel proper and I'm suggesting we move
>> it into a boot wrapper going forward.
>>
>
> That's not 100% true because as Segher said, prom_init.c is part of  
> the
> kernel (tree, image), but is what does the translation.

I'm not sure I follow.  I understand that prom_init.c is part of the  
kernel in ppc64.  I'm saying that such things should NOT be part of  
the arch/powerpc kernel going forward.  They should be handled via  
bootwrappers.

- kumar