Device trees

[Benno Rice]

On 24/07/2008, at 10:27 AM, Nathan Whitehorn wrote:

> Benno Rice wrote:
>> On 24/07/2008, at 8:47 AM, M. Warner Losh wrote:
>>> Does FreeBSD/powerpc on the MPC85xx machine use the fake device open
>>> firmware tree stuff from uboot (aka dts in the linux kernel  
>>> sources)?
>> I've got a machine (Mikrotik RouterBOARD 333, uses MPC8321) that  
>> has this.  I've been working with one of the dtc developers to port  
>> their code over to FreeBSD.  I'm trying to hide it underneath our  
>> existing OpenFirmware stuff.  I've got a few more bugs to get out  
>> of it but I can probably send you some patches early next week...
>
>
> Can you use this to abstract real OF too? We don't support real mode  
> Open Firmware and IBM is shipping new systems with a very basic  
> firmware that runs only in real mode (this includes the Bimini 970MP  
> dev board, apparently, as well as their Cell blades). The easiest  
> course seems to be just to pretend it's a flattened device tree if  
> we can support that.

My plan (assuming some measure of available time) was to actually get  
loader to handle turning OpenFirmware device data into an FDT which  
could be handed to FreeBSD as part of the loader metadata.  On  
platforms like the Mikrotik where all we get is an FDT, if we have  
loader it can just pass it through or if we're not using loader we can  
have a hook that shunts the data into the right place.

Does that sound workable?

-- 
Benno Rice
benno at jeamland.net