Re: [PATCH] Open Firmware device tree virtual filesystem

[Segher Boessenkool]

> > IMHO, the directory entries in the filesystem
> > should be in the form "node-name@unit-address" (eg: /pci@1f,0,
> > "pci" is the node name, "@" is the separator character defined
> > by IEEE 1275, and "1f,0" is the unit-address,
> > which are always guaranteed to be unique.
>
> They should be. The problem is buggy OF implementations. For example,
> both IBM and Apple OFs have the nasty habit of having under the CPU
> nodes an "l2-cache" node with no unit-address -and- a property with the
> same name

That is perfectly valid FWIW.  Not a "best practice" or anything,
but valid nonetheless.

Device tree semantics do not fit POSIX filesystem semantics 100%,
you do need some workarounds for some edge cases yes.

> > It's
> > not possible to have two ambiguously fully qualified nodes in the OFW
> > device tree, otherwise you would never be able to select
> > a specific one by name.
>
> Well, it happens to be the case though. The code is to work around 
> that.
> A normal bug-free tree should never trigger the workarounds.

Well it's not *technically* a bug to have two device nodes with
an exact identical path in OF, but sure :-)


Segher

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/