Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759008Ab3GZNrx (ORCPT ); Fri, 26 Jul 2013 09:47:53 -0400 Received: from mho-03-ewr.mailhop.org ([204.13.248.66]:54599 "EHLO mho-01-ewr.mailhop.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1758957Ab3GZNrv (ORCPT ); Fri, 26 Jul 2013 09:47:51 -0400 X-Mail-Handler: Dyn Standard SMTP by Dyn X-Originating-IP: 72.84.113.162 X-Report-Abuse-To: abuse@dyndns.com (see http://www.dyndns.com/services/sendlabs/outbound_abuse.html for abuse reporting information) X-MHO-User: U2FsdGVkX19vrsWT9WQSC0RW6DiD47kEJP2VkCx2PWw= Date: Fri, 26 Jul 2013 09:47:20 -0400 From: Jason Cooper To: David Woodhouse Cc: Richard Cochran , Mark Rutland , "devicetree@vger.kernel.org" , "ksummit-2013-discuss@lists.linuxfoundation.org" , Russell King - ARM Linux , Ian Campbell , Pawel Moll , Stephen Warren , Domenico Andreoli , "rob.herring@calxeda.com" , "linux-kernel@vger.kernel.org" , Jason Gunthorpe , Dave P Martin , "linux-arm-kernel@lists.infradead.org" Subject: Re: [Ksummit-2013-discuss] DT bindings as ABI [was: Do we have people interested in device tree janitoring / cleanup?] Message-ID: <20130726134720.GJ29916@titan.lakedaemon.net> References: <20130725175702.GC22291@e106331-lin.cambridge.arm.com> <51F168FC.9070906@wwwdotorg.org> <20130725182920.GA24955@e106331-lin.cambridge.arm.com> <20130725184834.GA8296@netboy> <20130725213753.GC17616@obsidianresearch.com> <20130726080115.GA5436@netboy> <1374831744.2923.42.camel@shinybook.infradead.org> <20130726130927.GC4219@netboy> <20130726132709.GH29916@titan.lakedaemon.net> <1374846070.14574.92.camel@i7.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1374846070.14574.92.camel@i7.infradead.org> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1472 Lines: 35 On Fri, Jul 26, 2013 at 02:41:10PM +0100, David Woodhouse wrote: > On Fri, 2013-07-26 at 09:27 -0400, Jason Cooper wrote: > > > > The other dynamic change that bears mentioning here is attributes which > > have been configured by the bootloader. For example, in mvebu, we have > > the Schrodinger's Cat register. It allows you to reconfigure the base > > address of the registers from *within* that register range. If the > > bootloader does this, the DT needs to be updated to reflect the current > > hardware configuration. Otherwise, the kernel is stuck poking around at > > memory addresses hoping to find something sane. > > > > But this falls into the same category as you mentioned, but outside of > > chosen {};. > > Yeah, /chosen was given as an example of stuff that's almost > *exclusively* "configuration" stuff. > > But there's plenty outside there that can reasonably change. > > It's OK to change the data, and of *course* the base address reported in > the DT should actually match reality *today*, if it changes on the fly. > > It's not OK to change the *schema* in which those data are expressed. > That's the ABI we're talking about. Agreed, much more clear than what I was saying. thx, Jason. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/