From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: Date: Thu, 16 Nov 2006 11:42:04 -0500 From: "Lei Sun" To: "Steven Blakeslee" Subject: Re: memory corruption after MMU turned on In-Reply-To: <1628E43D99629C46988BE46087A3FBB97AFFDC@ep-01.EmbeddedPlanet.local> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed References: <1628E43D99629C46988BE46087A3FBB97AFFDC@ep-01.EmbeddedPlanet.local> Cc: Linuxppc-embedded@ozlabs.org List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , I am using codewarrior and USB+TAP for debugging(didn't got BDI yet). One problem seems like if i set a break point at some place, when the code reach there, it did stopped, but the instruction on that location became 0x00000000 ! Any also, the kernel is loaded at physical address 0x0, how do i set the break point to 0xC000XXX address? I suppose i should set the break point at the physical address instead. I don't have the hardware to try right now. Thank you for your reply! lei On 11/16/06, Steven Blakeslee wrote: > Generally stepping over the rfi command will cause the problem. > Instead, set a breakpoint at the address that the rfi command will jump > to, the C000XXX address. Then step through code from then on. > > > > > -----Original Message----- > > From: > linuxppc-embedded-bounces+blakeslees=embeddedplanet.com@ozlabs.org > > [mailto:linuxppc-embedded- > > bounces+blakeslees=embeddedplanet.com@ozlabs.org] On Behalf Of Lei Sun > > Sent: Thursday, November 16, 2006 10:45 AM > > To: linuxppc-embedded@ozlabs.org > > Subject: memory corruption after MMU turned on > > > > 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 > > _______________________________________________ > > Linuxppc-embedded mailing list > > Linuxppc-embedded@ozlabs.org > > https://ozlabs.org/mailman/listinfo/linuxppc-embedded >