Lei, if you are trying to step over RFI using the BDI2000-probe (propably also with other probes), this problem could be caused by the probe.
I had similar problems in an early phase of an 8270 project. It is not possible to step over RFI; and it is always dangerous to debug through MMU initialization code with the probe. You could work around this by setting a Breakpoint instruction after MMU-initialization, hoping, that the code will reach this point. If also this doesnt help, i could only recommend to set some HW-signals, in the best case a register with LED's behind to see, whether your system reaches particular code areas. -- Mit freundlichen Gruessen / Best regards Claus Gindhart SW R&D Kontron Modular Computers phone :++49 (0)8341-803-374 mailto:[EMAIL PROTECTED] http://www.kontron.com -----BEGIN GEEK CODE BLOCK----- Version: 3.1 GU d- s++:>++:+ a+ C++$ !U !P L++>$ E-- W+(-) N- o? K? w !O !M V !PS PE- Y+ PGP+ t 5? X R* tv- b+ DI+++ D-- G e++> h--- !r x+++ ------END GEEK CODE BLOCK------ -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Lei Sun Sent: Donnerstag, 16. November 2006 16:45 To: [email protected] 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,[EMAIL PROTECTED] 244 ori r0,r0,[EMAIL PROTECTED] 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 [email protected] https://ozlabs.org/mailman/listinfo/linuxppc-embedded _______________________________________________ Linuxppc-embedded mailing list [email protected] https://ozlabs.org/mailman/listinfo/linuxppc-embedded
