On Sep 26, 2013, at 8:30 PM, Benjamin Herrenschmidt wrote: > 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. I'll poke Stuart to see what's going w/updating ePAPR. > 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. Either we update the section in general about 'ranges' or at least update the simple-bus binding to state that rules about the node name. > 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 :-) - k -- Employee of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation -- 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
