From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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 ESMTPS id E6254DDFDF for ; Thu, 7 Aug 2008 00:17:07 +1000 (EST) Message-Id: From: Kumar Gala To: Grant Likely In-Reply-To: <20080806060223.30717.35175.stgit@trillian.secretlab.ca> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Mime-Version: 1.0 (Apple Message framework v926) Subject: Re: [RFC/PATCH 1/3] powerpc: add ioremap_bat() function for setting up BAT translated IO regions. Date: Wed, 6 Aug 2008 09:07:40 -0500 References: <20080806055214.30717.86092.stgit@trillian.secretlab.ca> <20080806060223.30717.35175.stgit@trillian.secretlab.ca> Cc: linuxppc-dev@ozlabs.org, paulus@samba.org, miltonm@bga.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Aug 6, 2008, at 1:02 AM, Grant Likely wrote: > From: Grant Likely > > ioremap_bat() is useful for things like mapping SoC internally > memory mapped > register and early text because it allows mappings to devices to be > setup > early in the boot process where they are needed, and the mappings > persist > after the MMU is configured. > > Without ioremap_bat(), setting up the MMU would cause the early text > mappings to get lost and mostly likely result in a kernel panic on > the next > attempt at output. > > Signed-off-by: Grant Likely > --- why can't we just do this in ioremap itself? - k