From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Thu, 13 Feb 2014 19:53:17 +0000 Subject: [PATCH v2 3/3] PCI: ARM: add support for generic PCI host controller In-Reply-To: <20140213182654.GA20043@obsidianresearch.com> References: <1392236171-10512-1-git-send-email-will.deacon@arm.com> <20140213110721.GC13576@mudshark.cambridge.arm.com> <4110788.UI9TADVhpa@wuerfel> <20140213182654.GA20043@obsidianresearch.com> Message-ID: <20140213195317.GQ13576@mudshark.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Feb 13, 2014 at 06:26:54PM +0000, Jason Gunthorpe wrote: > On Thu, Feb 13, 2014 at 05:28:20PM +0100, Arnd Bergmann wrote: > > > > Huh? The reg property clearly has the size in it (as shown in the > > > example below). I guess I was just asking for the description > > > here to say what the size was for the 2 compatibles since its > > > fixed and known. > > > > It's still an open question whether the config space in the reg > > property should cover all 256 buses or just the ones in the > > bus-range. In the latter case, it would be variable (but > > predictable) size. > > The 'describe the hardware principle' says the reg should be the > entire available ECAM/CAM region the hardware is able to support. > > This may be less than 256 busses, as ECAM allows the implementor to > select how many upper address bits are actually supported. Ok, but the ECAM/CAM base always corresponds to bus 0, right? > IMHO, the bus-range should be used to indicate the range of busses > discovered by the firmware, but we have historically tweaked it to > indicate the max range of bus numbers available on this bus (I think > to support the hack where two physical PCI domains were roughly glued > into a single Linux domain). Ok, so this answers Kumar's point about the reg property. I'll augment it with a size. Will