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 58A59474C6 for ; Thu, 23 Oct 2008 01:59:52 +1100 (EST) Message-Id: <952F8E0B-3BFD-4E01-A032-2AFF5B4D31FA@kernel.crashing.org> From: Kumar Gala To: Matt Sealey In-Reply-To: <48FF3743.1000007@genesi-usa.com> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Mime-Version: 1.0 (Apple Message framework v929.2) Subject: Re: Extended Addressing Mode Date: Wed, 22 Oct 2008 09:59:22 -0500 References: <48FEEB88.6050505@kontron.com> <83735324-C37B-4C57-A50F-FFF0D133E4E3@kernel.crashing.org> <48FF23C4.5030408@kontron.com> <88C8EDEB-C9A5-4876-AF7D-55CBABBE111D@kernel.crashing.org> <48FF2DDE.9060301@genesi-usa.com> <48FF3743.1000007@genesi-usa.com> Cc: linuxppc-dev@ozlabs.org, =?ISO-8859-1?Q?R=E9gis_Odey=E9?= List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Oct 22, 2008, at 9:22 AM, Matt Sealey wrote: > > > Kumar Gala wrote: >> Your bigger issue is if you can setup the DDR controller for the >> hole you want. > > I just remembered;; > > ~~ > The CCSR window always takes precedence over all local access > windows. However, the CCSR window must not overlap an LAW that maps > to the DDR controller. Otherwise, undefined behavior occurs. > ~~ > > So, it's not really possible to map 4GB of RAM in the lower 32-bit > area, without interacting badly with the CCSR. This means you're > forced to select a 2GB LAW for DDR, then leave 2GB free, then map > the rest above.. using more than 2Gb therefore absolutely requires > non-contiguous memory..? As I said, its all about your physical DDR layout. If you have two DDR dimms each 2Gb you can do: 0..2G - DDR DIMM A 2G..4G - IO 4G..6G - DDR DIMM B - k