On Thu, 2013-09-26 at 17:12 -0600, Stephen Warren wrote: > Well, ePAPR seems pretty specific that unit address and reg are > related, > but says nothing about ranges in the section on node naming, nor about > node naming in the section about ranges. > > I'd claim that the existing PPC trees are nonconforming, and should be > fixed too:-) This is tricky, we should probably fix ePAPR here. If you have a "soc" bus covering a given range of addresses which it forwards to its children devices but doesn't have per-se its own registers in that area, then it wouldn't have a "reg" property. I would thus argue that in the absence of a "reg" property, if a "ranges" one is present, the "parent address" entry in there is an acceptable substitute for the "reg" property as far as unit addresses are concerned. Also don't forget that in real OFW land, the unit address is something that's somewhat bus specific ... for example, PCI uses "dev,fn" rather than the full 96-bit number of the "reg" entry :-) Another option which would more strictly conform to ePAPR and in fact to of1275 would be to require such bus nodes to have a "reg" property with the address value set to the beginning of the range and the size value set to 0 :-) Cheers, Ben -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
