From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <segher@kernel.crashing.org>
Received: from gate.crashing.org (gate.crashing.org [63.228.1.57])
	(using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits))
	(Client did not present a certificate)
	by ozlabs.org (Postfix) with ESMTP id 24887DDEDD
	for <linuxppc-dev@ozlabs.org>; Fri, 20 Jul 2007 02:54:46 +1000 (EST)
In-Reply-To: <469E4432.5050900@freescale.com>
References: <1184161957.32199.52.camel@weaponx.rchland.ibm.com>
	<1184162389.32199.65.camel@weaponx.rchland.ibm.com>
	<4EAC985A-2F04-465D-AB69-C67807310D7B@kernel.crashing.org>
	<9696D7A991D0824DBA8DFAC74A9C5FA3030669AF@az33exm25.fsl.freescale.net>
	<28A3F6B9-512B-4D86-8E0D-A7680CCE2354@kernel.crashing.org>
	<1184622446.25235.89.camel@localhost.localdomain>
	<C2D29334-489F-49B0-8220-0D94E89FEAC3@kernel.crashing.org>
	<1184707558.25235.159.camel@localhost.localdomain>
	<20070717222507.GA4682@ld0162-tx32.am.freescale.net>
	<A86AB8AE-E421-457B-ABE8-9AD93CCFCDC8@kernel.crashing.org>
	<469E4432.5050900@freescale.com>
Mime-Version: 1.0 (Apple Message framework v752.2)
Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
Message-Id: <E617296B-7950-46AC-8400-68168DED057F@kernel.crashing.org>
From: Segher Boessenkool <segher@kernel.crashing.org>
Subject: Re: [RFC][PATCH 6/8] Walnut DTS
Date: Thu, 19 Jul 2007 18:54:32 +0200
To: Scott Wood <scottwood@freescale.com>
Cc: Yoder Stuart-B08248 <stuart.yoder@freescale.com>, linuxppc-dev@ozlabs.org
List-Id: Linux on PowerPC Developers Mail List <linuxppc-dev.ozlabs.org>
List-Unsubscribe: <https://ozlabs.org/mailman/listinfo/linuxppc-dev>,
	<mailto:linuxppc-dev-request@ozlabs.org?subject=unsubscribe>
List-Archive: <http://ozlabs.org/pipermail/linuxppc-dev>
List-Post: <mailto:linuxppc-dev@ozlabs.org>
List-Help: <mailto:linuxppc-dev-request@ozlabs.org?subject=help>
List-Subscribe: <https://ozlabs.org/mailman/listinfo/linuxppc-dev>,
	<mailto:linuxppc-dev-request@ozlabs.org?subject=subscribe>

>> Yes indeed.  The problem with your suggested "obvious way"
>
> I said it was obvious, not obviously correct. :-)

I know :-)

>> is that you wouldn't get a unit address included if your
>> interrupt-map points (for some entry) at your device tree
>> parent, either.  Not all that hypothetical.
>
> Ah, good point.  My inclination would be to, rather than check how  
> we got to the node, check whether it's the device's parent.  If  
> not, then the presence of #address-cells (other than zero for  
> compatibility) is an error.  Otherwise, #address-cells is used, and  
> defaults are handled the same as with reg/ranges translation.

This might work; it is less flexible than the actual interrupt
mapping definition though (and such flexibility is good, as long
as you don't abuse it ;-) ).  Anyway, we're stuck with the actual
current imap recommended practice.  It might not be perfect but
it does work, is proven in the field, and is the standard.


Segher