From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: In-Reply-To: <20070912035351.GF20218@localhost.localdomain> References: <20070912031132.GC20218@localhost.localdomain> <20070912035351.GF20218@localhost.localdomain> Mime-Version: 1.0 (Apple Message framework v623) Content-Type: text/plain; charset=US-ASCII; format=flowed Message-Id: <44b4b3a133980aeb6c596aad71612e6c@kernel.crashing.org> From: Segher Boessenkool Subject: Re: [PATCH v3] [POWERPC] 85xx: Add basic Uniprocessor MPC8572 DS port Date: Wed, 12 Sep 2007 16:00:38 +0200 To: David Gibson Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , >>>> + uli1575@0 { >>>> + reg = <0 0 0 0 0>; >>> >>> This looks kind of bogus... >> >> Its a PCIe to PCI bridge that is transparent. > > Right.... if it has no control registers, I think it should just lack > 'reg', not define a zero-length register block. "reg" for PCI config registers has length 0 always, it's defined that way in the PCI binding. But if this thing is transparent, it doesn't have PCI config regs. >>>> + #size-cells = <2>; >>>> + #address-cells = <3>; >>>> + ranges = <02000000 0 80000000 >>>> + 02000000 0 80000000 >>>> + 0 20000000 >>>> + 01000000 0 00000000 >>>> + 01000000 0 00000000 >>>> + 0 00100000>; > > And if truly transparent, it should perhaps have just ranges; > indicating that child addresses are identity mapped to parent > addresses. If truly transparent, the node should just not be there at all! >>>> + pci_bridge@0 { >>> >>> Ok.. why is pci_bridge nested within uli1575 - with the matching reg >>> and ranges, it looks like they ought to be one device. Also if this >>> is a PCI<->PCI bridge, I believe it shold have device_type = "pci". >> >> We've been using this as it stands for a while. If there are some >> changes here that make sense I'm willing to make them. > > Right, at present I don't see why you couldn't just ditch the > pci_bridge node, and drop its contents straight into the uli1575 node. Yeah. The preferred name for PCI-to-PCI bridge nodes is simply "pci", btw. Segher