From mboxrd@z Thu Jan 1 00:00:00 1970 From: Scott Wood Subject: Re: commit e38c0a1f breaks powerpc boards with uli1575 chip Date: Thu, 2 Jan 2014 18:04:17 -0600 Message-ID: <1388707457.11795.32.camel@snotra.buserror.net> References: <201312171135.38576@blacky.localdomain> <52B1EC15.5070606@gmail.com> <201312190842.02702@blacky.localdomain> <1388373200.4373.25.camel@pasglop> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1388373200.4373.25.camel@pasglop> Sender: linux-kernel-owner@vger.kernel.org To: Benjamin Herrenschmidt Cc: Nikita Yushchenko , "devicetree@vger.kernel.org" , Arnd Bergmann , Dmitry Krivoschekov , Alexey Lugovskoy , Thierry Reding , linux-kernel@vger.kernel.org, Rob Herring , Grant Likely , linuxppc-dev@lists.ozlabs.org List-Id: devicetree@vger.kernel.org On Mon, 2013-12-30 at 14:13 +1100, Benjamin Herrenschmidt wrote: > On Thu, 2013-12-19 at 08:42 +0400, Nikita Yushchenko wrote: > > No, this does not help. > > > > I've dumped the actual content of 'range' and 'addr' at the failure > > point > > (i.e. ar point that returns error with e38c0a1f but passes without > > e38c0a1f ): > > > > OF: default map, cp=0, s=10000, da=70 > > range: 01 00 00 00 00 00 00 00 00 00 00 00 > > addr: 00 00 00 00 00 00 00 00 00 00 00 70 > > Something that has a #address-cells larger than 2, or more generally, > an address field that contains more than a single number, must have > a specific translation backend, like we have for PCI. > > This is a bit annoying but originates from the original OFW stuff on > which this stuff is based where the bus node would provide the methods > for translation. I can maybe see that for PCI which has a special encoding, but why is it always needed? E.g. if Freescale localbus had a 64-bit offset instead of 32-bit, the child nodes would have 3 address cells, but straightforward use of ranges would bring it down to 2 for the final physical address. Existing localbus nodes already have "an address field that contains more than a single number"; it's just a simple enough encoding that it works to treat it as if it were a single large number. -Scott