Device trees
Benno Rice
benno at jeamland.net
Thu Jul 24 03:59:12 UTC 2008
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
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