From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-in-07.arcor-online.net (mail-in-07.arcor-online.net [151.189.21.47]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mx.arcor.de", Issuer "Thawte Premium Server CA" (verified OK)) by ozlabs.org (Postfix) with ESMTP id AA4A2DDFAC for ; Thu, 22 Mar 2007 00:49:35 +1100 (EST) In-Reply-To: <20070320035005.GB21124@localhost.localdomain> References: <20070316172641.GA29709@ld0162-tx32.am.freescale.net> <20070316172757.GC29784@ld0162-tx32.am.freescale.net> <20070320035005.GB21124@localhost.localdomain> Mime-Version: 1.0 (Apple Message framework v623) Content-Type: text/plain; charset=US-ASCII; format=flowed Message-Id: From: Segher Boessenkool Subject: Re: [PATCH 03/17] bootwrapper: Add xlate_reg(), and use it to find serial registers. Date: Wed, 21 Mar 2007 14:49:30 +0100 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: , >> xlate_reg() uses the ranges properties of a node's parentage to find >> the >> absolute physical address of the node's registers. >> >> The ns16550 driver uses this when no virtual-reg property is found. > > This is a pretty large chunk of code for use on just some platforms. > Remind me why we can't just insist on the presence of virtual-reg? Because "virtual-reg" is evil and should preferably never be used? On the other hand, address translation for directly memory mapped devices via "ranges" properties is a darn solid, quite flexible, and proven mechanism. I didn't look at the actual code but it should be really small; I hope it doesn't copy the Linux code with its millions of workarounds for broken device trees -- we should insist on correct trees, or even just fix them if they *are* broken ;-) Segher