From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.ebshome.net (gate.ebshome.net [208.106.21.240]) (using TLSv1 with cipher EDH-RSA-DES-CBC3-SHA (168/168 bits)) (Client CN "gate.ebshome.net", Issuer "gate.ebshome.net" (not verified)) by ozlabs.org (Postfix) with ESMTP id EF76A67DA7 for ; Thu, 5 Oct 2006 16:29:28 +1000 (EST) Date: Wed, 4 Oct 2006 23:29:26 -0700 From: Eugene Surovegin To: Paul Mackerras Subject: Re: [PATCH 10/11] Add MPC8360EMDS board support Message-ID: <20061005062926.GB1985@gate.ebshome.net> References: <20060927155626.4d5ca19c@vitb.ru.mvista.com> <4879B0C6C249214CBE7AB04453F84E4D19D865@zch01exm20.fsl.freescale.net> <20060927165556.04c8d5d7@vitb.ru.mvista.com> <20060927112201.293fef44@localhost.localdomain> <17699.769.632098.479906@cargo.ozlabs.ibm.com> <2867EA41-5135-43F7-9873-044C617EAC1B@embeddedalley.com> <17700.20834.792693.853677@cargo.ozlabs.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <17700.20834.792693.853677@cargo.ozlabs.ibm.com> Cc: Olof Johansson , linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, Oct 05, 2006 at 10:27:14AM +1000, Paul Mackerras wrote: > Dan Malek writes: > > > I'm not against using the device tree (or platform data > > or #defines) when it's appropriate to do so. I think our > > obsession to represent everything there is what is > > creating the complexity. If a #define in a board > > specific port file makes sense, then just do that, > > even if it is a BSCR address. > > So, where this discussion started was that I saw an ioremap in an > ethernet driver using a physical address defined with #define, and I > said "that should go in the device tree". And I would still say that > if the ioremap was still there, since the driver is one that is useful > across a range of boards and chips. > > My other point would be that what you say is valid *until* the > hardware engineers come to you and say "we're doing rev 2 of the > board, and we had to move the BCSR a bit. That's OK with you, isn't > it?". > > If you have the BCSR address in the device tree, you don't even need > to recompile your kernel. You can just copy your board.dts to > board-rev2.dts, change the address in there, and rerun the wrapper > script to create the flash image to put on the new board. Or if you > are using a bootloader that knows how to supply a device-tree blob, > you just put board-rev2.dtb into flash along with your existing kernel > image. Paul, it doesn't really matter if you have to rebuild a kernel or some other blob and have it re-flashed in the actual board. Having something in device tree doesn't change a simple fact that you have to update some firmware component, be it boot code, kernel or some dts blob. You still have to prepare new flash image, period. -- Eugene