From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755253Ab2LCO1S (ORCPT ); Mon, 3 Dec 2012 09:27:18 -0500 Received: from mail-wi0-f170.google.com ([209.85.212.170]:53466 "EHLO mail-wi0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754780Ab2LCO1R (ORCPT ); Mon, 3 Dec 2012 09:27:17 -0500 From: Grant Likely Subject: Re: [PATCH] of: When constructing the bus id consider assigned-addresses as well To: Jason Gunthorpe Cc: linux-kernel@vger.kernel.org, devicetree-discuss@lists.ozlabs.org, Rob Herring In-Reply-To: <20121201004948.GA3185@obsidianresearch.com> References: <20121121210240.GC15285@obsidianresearch.com> <20121126140316.99FE23E194B@localhost> <20121126182054.GA30177@obsidianresearch.com> <20121129162648.80DBC3E0912@localhost> <20121129193829.GA10145@obsidianresearch.com> <20121130094806.0D6D73E070C@localhost> <20121201004948.GA3185@obsidianresearch.com> Date: Mon, 03 Dec 2012 14:27:11 +0000 Message-Id: <20121203142711.591853E0A4C@localhost> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 30 Nov 2012 17:49:48 -0700, Jason Gunthorpe wrote: > On Fri, Nov 30, 2012 at 09:48:05AM +0000, Grant Likely wrote: > > > > If you attempt to stick a 'reg' in a block nested below a > > > 'device_type="pci"' the kernel throws lots of error messsages and > > > generates bad address mappings. > > > > Have you added the appropriate #address-cells and #size-cells to the pci > > device node to go back to a non-pci addressing mode? > > assigned-addresses > > Switching away from the 5 dword address format is not ideal > because then there is no way to specify the resource region (prefetch, > io, mmio) and mmio would have to be assumed. You don't need to switch away from using 5 cells if that works best for you, but I'd be surprised if it was the ideal representation. I would expect you to use a representation that makes sense for the internal bus architecture of the device. If if exactly matches the PCI address, then go ahead with 5 cells, but if it is one or more 32bit busses, then use 1 or 2 for #address-cells and 1 for #size-cells. > > > only makes sense in the pci-device node itself. reg should work for all > > nodes below that, and if it doesn't then it is a bug that we need to > > fix. > > Okay.. but how should the DTS be constructed? > pcie_bus { // The PCI-E bus device_type = "pci"; ranges = <5dw ranges>; #address-cells = <3>; #size-cells = <2>; soc_bridge { // The PCI-E device device_type = "pci"; // These are important to set up the address format in the child // nodes #address-cells = <3>; #size-cells = <2>; // Translation from PCI bus space to local bus space. ranges = <5dw ranges>; soc_device { // Internal device reg = <5dw regs> }; }; }; > > This is what I have now, the soc_bridge PCI-E device is DTS modeled as > a PCI bridge - it has a ranges with its memory location, and the > children nodes are relative to those ranges. This would not be typical > for a non-bridge PCI-E device. Now, if the children of soc_bridge really are PCI devices (and not just plain-vanilla memory mapped IP cores like I assume above), then they shouldn't be registered in the kernel as platform_devices at all. In that case register them as PCI devices and the existing PCI infrastructure should do the naming correctly. > The reason for the 'assigned-address' requirement with the current > kernel code is the device_type=pci on soc_bridge. This makes > of_match_bus(parent) for soc_device return the PCI structure, which > has '.addresses = "assigned-addresses",' If the soc_devices are getting triggered on that and they shouldn't be, then we need a mechanism in the soc_bridge node to kick out of that behavoir for its children. g.