Messages in this thread | | | Subject | Re: [dtc PATCH V2] Warn on node name unit-address presence/absence mismatch | From | Kumar Gala <> | Date | Fri, 27 Sep 2013 10:39:08 -0500 |
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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
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