From mboxrd@z Thu Jan 1 00:00:00 1970 From: Detlev Zundel Date: Wed, 14 Nov 2007 12:02:10 +0100 Subject: [U-Boot-Users] post memory test In-Reply-To: (Dongying Xu's message of "Mon\, 12 Nov 2007 15\:50\:39 -0800") References: Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi Dongy, > I have a question about post memory test. According to the following code, even > if memory size is greater than 256M, only 256M memory will be tested. Is it > true or I missed something. Thanks a lot. No, this is true. As I did not write that code, my interpretation uses some speculation, but what is very likely the case here is that U-Boot potentially does not map all physical available memory and thus we cannot even access it. As we do not have explicit variables representing those facts, I guess the 256MB are kind of a least common denominator. As an example look at initdram() in board/Marvell/db64460/sdram_init.c where the platform uses Block Address Translations (BATs) to map RAM but exhausts these pretty scarce ressources and limits itself to mapping only the first 256MB (a usual limit for a BAT). > In U-BOOT-1.2.0 > u-boot\post\drivers\memory.c, A word to version 1.2.0, if you have a platform with 256MB+ memory, please be sure to check the fix from Aug 25 by Yuri Tikhonov "POST: limit memory test area to not touch global data anymore" (9c02defc) in the current code as the code in 1.2.0 caused problems on such systems. Cheers Detlev -- When you loosen yourself from all the obvious delusions - religion, ideology, Communism - you're still left with the myth of your own goodness. Which is the final delusion. -- Philip Roth -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-40 Fax: (+49)-8142-66989-80 Email: dzu at denx.de