From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from wx-out-0506.google.com (wx-out-0506.google.com [66.249.82.238]) by ozlabs.org (Postfix) with ESMTP id A32FF67BE2 for ; Fri, 17 Nov 2006 02:44:33 +1100 (EST) Received: by wx-out-0506.google.com with SMTP id i31so624013wxd for ; Thu, 16 Nov 2006 07:44:31 -0800 (PST) Message-ID: Date: Thu, 16 Nov 2006 10:44:31 -0500 From: "Lei Sun" To: linuxppc-embedded@ozlabs.org Subject: memory corruption after MMU turned on MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi all: I am trying to bring up customized board based on MPC8270, the kernel version is 2.4.30, it works fine on one of the Eval board (PQ2FADS-VR, which use MPC8275). The kernel hangs after uncompressing is done, further debug shows that it hangs right after "rfi " instruction of the turn_on_mmu: function in head.S turn_on_mmu: 240 mfmsr r0 241 ori r0,r0,MSR_DR|MSR_IR 242 mtspr SRR1,r0 243 lis r0,start_here@h 244 ori r0,r0,start_here@l 245 mtspr SRR0,r0 246 SYNC 247 RFI /* enables MMU */ After i step over the RFI instruction, the PC points to C000XXX , but all memory content is 0 by then. my BATU0 is 0xC000FFE0 BATL0 is 0x00000002, I have 128MB RAM. The u-boot works fine, without MMU turned on. We do have some hardware problem, such that i have to lower the bus frequency to make the SDRAM stable. What physical parameter could cause the board not working with MMU on? Any suggestion? Thanks lei