On Thu, 2006-11-16 at 10:44 -0500, Lei Sun wrote: > 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?
When MMU turn on, the kernel memory should be cacheable, so the processor will burst read instructions from memory to i-cache. Did you do the burst read/write memory test in u-boot? As you said, you did not do the test. -Dave _______________________________________________ Linuxppc-embedded mailing list [email protected] https://ozlabs.org/mailman/listinfo/linuxppc-embedded
