Nikhil Gautam wrote:
Hi Everyone,
I am try to use the u-boot to program the NOR flash on my proprietary board based on AMCC sequoia board. I can boot from 1Gb NAND flash ok but everytime I try access the last 4K of NOR flash, U-boot gives me following error and reboots:-
{{{ U-Boot$ md 0xFFFFF000 fffff000:Bus Fault @ 0x00000000, fixup 0x00000000 Machine check in kernel mode. Caused by (from msr): regs 0fe8fca8 Unknown values in msr NIP: 00000000 XER: 20000000 LR: 0FF6412C REGS: 0fe8fca8 TRAP: 0200 DAR: 041F0000 MSR: 00000000 EE: 0 PR: 0 FP: 0 ME: 0 IR/DR: 00
GPR00: 0FF6412C 0FE8FD98 7FFFFFFF EF600300 00000000 00000001 00000001 C838AE89 GPR08: 0FF5145C 00000000 01FCA055 03F940AB 0FE8FB50 041F0000 0FFACD00 0EED0000 GPR16: 00000000 00000000 00000000 00000000 0FE8FDA0 00000040 0FE8FDA0 0FE8FDA0 GPR24: 00000000 00000100 00000010 00000004 FFFFF000 0FE8FF40 0FFADB58 0FE8FDA0 Call backtrace: machine check }}}
I get the same error if I press "ENTER" after u-boot gives me the prompt. If I type some command its ok and then its fine thereafter.
I know the NOR flash is ok because I used BDI to program it and also I can access this address when I boot from NOR flash.
Any Clue?
Thanks In Advance!
Nikhil Gautam
Hi Nikhil,
If I understand you correctly, this sounds like improperly initialized variables in your build. This is very likely a (build | link | initialization | relocation) issue (pick any combination).
The "md 0xFFFFF000" command is using the default value for the number of objects, which comes from a static variable dp_last_length that is initialized to 0x40 (see common/cmd_mem.c): uint dp_last_length = 0x40;
If dp_last_length is not initialized properly to 0x40 on start up, unexpected things are going to happen. I don't see an obvious path to an illegal access to location 0x00000000, but it could be.
In addition, if you hit <enter> with no command the first time your board boots, the command parser tries to run the last command you executed. Of course, there *is no* "last command", which ties into my theory of uninitialized static/global variables.
I would suspect your link control isn't linking the static variable initialization in the right section or your (compiler's) initialization of the static variables isn't working as expected.
HTH, gvb