From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Wed, 8 Aug 2007 11:13:24 +1000 From: David Gibson To: Segher Boessenkool Subject: Re: [PATCH 2/6] PowerPC 440EPx: Sequoia DTS Message-ID: <20070808011324.GD25082@localhost.localdomain> References: <65ff446478a9fd0a48061079d5f04f8f@kernel.crashing.org> <20070801050422.GI31391@localhost.localdomain> <20070801054751.GM31391@localhost.localdomain> <46B1F6D4.3070707@ru.mvista.com> <20070803031349.GD6418@localhost.localdomain> <46B34E1F.5060009@ru.mvista.com> <20070806042109.GB6103@localhost.localdomain> <163e1bcdc507ddcde3193e842c96da43@kernel.crashing.org> <20070807041259.GF13522@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, Aug 07, 2007 at 06:51:04PM +0200, Segher Boessenkool wrote: > >> address-permutation = <0 1 3 2 4 5 7 6 e f d c a b 9 8>; > > > > Yes, I was contemplating something like that. > > Let's not define this until we need it though :-) Indeed. > >> I haven't heard or thought of anything better either. Using "ranges" > >> is conceptually wrong, even ignoring the technical problems that come > >> with it. > > > > Why is "ranges" conceptually wrong? > > The flash partitions aren't separate devices sitting on a > "flash bus", they are "sub-devices" of their parent. Well, yes, but nonetheless the partitions show up as part of the overall physical address space. How do you encode that other than in 'ranges'? > > To be honest this looks rather to me like another case where having > > overlapping 'reg' and 'ranges' would actually make sense. > > It never makes sense. You should give the "master" device > the full "reg" range it covers, and have it define its own > address space; "sub-devices" can carve out their little hunk > from that. You don't want more than one device owning the > same address range in the same address space. Why not? After all, the physical address ranges of the flash partitions really do overlap with that of the flash device as a whole. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson