Device trees

[Benno Rice]

On 24/07/2008, at 1:38 PM, M. Warner Losh wrote:

> In message: <D33D2388-8237-406D-8162-1DF9013277A2 at jeamland.net>
>            Benno Rice <benno at jeamland.net> writes:
> :
> : 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.
>
> Cool!
>
> : 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...
>
> That's basically what Linux does.  They force the boot loader to pass
> in all kinds of information about the system.  This makes a lot of
> sense, I think.
>
> Are you booting /boot/loader?  Or directly booting the kernel from
> uboot?

s/uboot/RouterBOOT/ =)

Directly booting.  RouterBOOT supports netbooting but doesn't provide  
hooks that loader can use to do anything itself.  It also only  
supports yaffs2 as a local boot filesystem.  I'm going to look into  
porting yaffs2 at some point.

The only thing RouterBOOT hands us is a pointer to a flattened device  
tree a-la what uboot hands to Linux so I need to be able to handle it  
to get things like memory sizes/locations, SoC base addresses and  
where the hell my console is. =)

-- 
Benno Rice
benno at jeamland.net