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Stack Pointer Problem: MPC8270 Custom Board

U-Boot-Users mss59 at att.net 2 participants 2 messages Oct 20, 2003

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I am working on an MPC8270 based custom board. u-boot is ported from EP8260 board version. RAM is 128M, flash is 16M.
After u-boot relocates code in the ram, sometimes, stack pointer gets corrupted. And sometimes, I get bus fault which overwirtes all u-boot area in the RAM with some pattern like this

bus fault
07f6bcd0 : 02001111 07f6be18 07f6bc68 11111111 ...........h.... 07f6bce0 : 42757320 4661756c 74204020 30782020 Bus Fault @ 0x 07f6bcf0 : 20202020 20202020 20202020 20202020
07f6bd00 : 20202020 20202020 20202020 20202020
07f6bd10 : 20202020 20202020 20202020 20202020
07f6bd20 : 20202020 20202020 20202020 20202020
07f6bd30 : 20202020 20202020 20202020 20202020
07f6bd40 : 20202020 20202020 20202020 20202020
07f6bd50 : 20202020 20202020 20202020 20202020
07f6bd60 : 20202020 20202020 20202020 20202020
07f6bd70 : 20202020 20202020 20202020 20202020
07f6bd80 : 20202020 20202020 20202020 20202020
07f6bd90 : 20202020 20202020 20202020 20202020
07f6bda0 : 20202020 20202020 20202020 20202020
07f6bdb0 : 20202020 20202020 20202020 20202020
07f6bdc0 : 20202020 20202020 20202020 20202020 ---> This patters is written till the end of ram.
BDImn8270>rd
GPR00: 00000000 07f6bbd0 ffdfffff 08000004
GPR04: 00000000 00000010 07f58a9d 00000007
GPR08: 00000001 00000000 00000000 00000007
GPR12: 00000020 00400000 07ffd000 080cc000
GPR16: fffdffff bffdffff ff7fffff fff7ef5f
GPR20: 48000002 07f6bad0 00000000 07fcf098
GPR24: 07f6bce0 00000001 07fecdbc 07f6bfb4
GPR28: 07f6bcee 07f6bf70 07ffdcb8 07ff2ed8
CR : 48000002 MSR: 00000000

Any ideas.....

Thanks

Ravi.

#1 lore raw
Quoted 5 lines · In message <[email protected]> you wrote:

I am working on an MPC8270 based custom board. u-boot is ported from EP8260 board version. RAM is 128M, flash is 16M.
After u-boot relocates code in the ram, sometimes, stack pointer gets corrupted. And sometimes, I get bus fault which overwirtes all u-boot area in the RAM with some pattern like this

...

Quoted 1 line

Any ideas.....

As usual: you RAM initialization sequence is not correct.

And yes, that's a FAQ.

Best regards,

Wolfgang Denk

Signature · 3 lines
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
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