[U-Boot] mtest fails in MPC8280 board, , machine check exception error

[GurumurthyGowdar]

Dear All,
         i am using MPC8280 in our board which has 512MB of SDRAM i.e. from micron. 

when i give command mtest to check memory from U-boot, machine check and program exception is coming after 40 - 60mins later it hangs.

i have checked the SDRAM configuration settings everything is fine as per the device datasheet.

please i want to know where is the problem, what is the cause for this exception. why memory fails after 40-50mins.

error output is as attached:-

U-Boot 1.3.1 (Jul 27 2009 - 17:27:10)

MPC8260 Reset Status: External Soft, External Hard

MPC8260 Clock Configuration
 - Bus-to-Core Mult 3x, VCO Div 4, 60x Bus Freq  16-50 , Core Freq  50-150
 - dfbrg 1, corecnf 0x10, busdf 4, cpmdf 1, plldf 0, pllmf 4, pcidf 3
 - vco_out  500000000, scc_clk  125000000, brg_clk   31250000
 - cpu_clk  300000000, cpm_clk  250000000, bus_clk  100000000

CPU:   MPC8260 (HiP7 Rev 14, Mask 1.0 1K49M) at 300 MHz
Board: MPC8280 Based Remote IO CARD.SLN Technologies Pvt Ltd.
I2C:   ready
DRAM:  512 MB
FLASH: ## Unknown FLASH on Bank 0 - Size = 0x00000000 = 0 MB
256 MB
*** Warning - bad CRC, using default environment

In:    serial
Out:   serial
Err:   serial
Net:   FCC2 ETHERNET
RIO->

RIO->

RIO->mtest 0x2000 0x1ff00000


Pattern 00000000  Writing...            Reading...
Pattern FFFFFFFF  Writing...            Reading...
Pattern 00000001  Writing...            Reading...
Pattern FFFFFFFE  Writing...            Reading...
Pattern 00000002  Writing...            Reading...
Pattern FFFFFFFD  Writing...            Reading...
Pattern 00000003  Writing...            Reading...
Pattern FFFFFFFC  Writing...            Reading...
Pattern 00000004  Writing...            Reading...
Pattern FFFFFFFB  Writing...            Reading...
Pattern 00000005  Writing...            Reading...
Pattern FFFFFFFA  Writing...            Reading...
Pattern 00000006  Writing...            Reading...
Pattern FFFFFFF9  Writing...            Reading...
Pattern 00000007  Writing...            Reading...
Pattern FFFFFFF8  Writing...            Reading...
Pattern 00000008  Writing...            Reading...
Pattern FFFFFFF7  Writing...            Reading...
Pattern 00000009  Writing...            Reading...
Pattern FFFFFFF6  Writing...            Reading...
Pattern 0000000A  Writing...            Reading...
Pattern FFFFFFF5  Writing...            Reading...
Pattern 0000000B  Writing...            Reading...
Pattern FFFFFFF4  Writing...            Reading...
Mem error @ 0x1C593D38: found F8E9B800, expected F8E9B8A6

Mem error @ 0x1D0037F8: found F8BFF900, expected F8BFF9F6

Mem error @ 0x1D582E78: found F8A9FC00, expected F8A9FC56

Mem error @ 0x1D80BF68: found F89FD800, expected F89FD81A
Machine check in kernel mode.
Caused by (from msr): regs 1ffa1cd0 Unknown values in msr
NIP: 1FFE0048 XER: 20000000 LR: 1FFE0054 REGS: 1ffa1cd0 TRAP: 0200 DAR: 00000000
MSR: 0000b000 EE: 1 PR: 0 FP: 1 ME: 1 IR/DR: 00

GPR00: 1FFE0054 1FFA1DC0 EFFFFFFF 1FFF3308 1D8D0A18 F1398ADC F89CC56E 00000030 
GPR08: 00000041 F0000088 00000000 F0000091 1FFA1B78 FFF7FEFB 1FFFE000 1FFF44B8 
GPR16: 1FFF6E08 00000000 00000000 00000000 1FFF32D0 1FFF32F8 1FFF32FC 1FFF3308 
GPR24: FFFFFFFF 00002000 1FF00000 FFFFFFF4 7F9CC213 1FFA1F6C 1FFFE7F4 1D8D0A1C 
Call backtrace: 
machine check
 
do help me out in this regard,

with thanks and regards,
gurumurthy