Re: [PATCH] Open Firmware device tree virtual filesystem

Benjamin Herrenschmidt
2007-01-02T21:47:37Z

> All should converge on the same interface. That does not
> ab initio mean we should converge on what you currently
> have (although that might eventually be that case).

Well, Dave and I will happen to be in the same place in a few weeks for
LCA so we might spend some time having a look there if we don't have any
better to do :-)

> Leaving aside the issue of in-memory or not, I don't think
> it is realistic to think any completely common implementation
> will work for this -- it might for current SPARC+PowerPC+OLPC,
> but more stuff will be added over time...

And ? I don't see why a mostly common implementations wouldn't work,
provided that we provide hooks in the right place.

It's pretty clear to me that the actual construction of the in-memory
tree will remain platform specific (powerpc has this flattened format
used for the trampoline for example and so far, I don't think other
platforms plan to use it, though it might be a good idea too :-) sparc
has "issues" related to firmwares that aren't quite OF, etc...)

But it's also clear that the in-kernel representation, accessors and
filesystem could/should be totally identical, including all we build on
top, like prom_parse, of_device/of_platform device stuff etc.. (for
which I need to re-sync with davem too btw, as he did some fixes that I
didn't backport to powerpc... sigh)

The other -one- thing that has to be different is the write back for
properties that can be changed (/options typically) where the write back
mecanism is definitely platform specific.

Ben.