Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753711Ab3I0PjK (ORCPT ); Fri, 27 Sep 2013 11:39:10 -0400 Received: from smtp.codeaurora.org ([198.145.11.231]:48245 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752458Ab3I0PjH convert rfc822-to-8bit (ORCPT ); Fri, 27 Sep 2013 11:39:07 -0400 Subject: Re: [dtc PATCH V2] Warn on node name unit-address presence/absence mismatch Mime-Version: 1.0 (Apple Message framework v1283) Content-Type: text/plain; charset=us-ascii From: Kumar Gala In-Reply-To: <1380245438.28561.86.camel@pasglop> Date: Fri, 27 Sep 2013 10:39:08 -0500 Cc: Stephen Warren , Jon Loeliger , David Gibson , Olof Johansson , frowand.list@gmail.com, Tomasz Figa , devicetree@vger.kernel.org, Linux Kernel list , Marek Szyprowski , Rob Herring , Grant Likely , Stephen Warren , Rohit Vaswani Content-Transfer-Encoding: 8BIT Message-Id: <23CCE8D1-AEB2-42C8-B8C6-0B782117C4C2@codeaurora.org> References: <1379613263-32080-1-git-send-email-swarren@wwwdotorg.org> <3D2FE31C-A6BB-4F70-9B3B-C55012CB56B3@codeaurora.org> <5244BF7A.4000100@wwwdotorg.org> <1380245438.28561.86.camel@pasglop> To: Benjamin Herrenschmidt X-Mailer: Apple Mail (2.1283) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1929 Lines: 45 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 linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/