[U-Boot] U-boot hangs in mtest in MPC8280 Board

[GurumurthyGowdar]

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

when i give command mtest  only for 1MB to check memory test from U-boot, machine check and program exception is coming after 40 - 60mins later it hangs giving program check exception

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 test fails after 40-60mins.

error output is as attached:-

MPC8260 Reset Status: Check Stop, External Soft, External Hard

MPC8260 Clock Configuration
 - Bus-to-Core Mult 5x, VCO Div 2, 60x Bus Freq  20-60 , Core Freq 100-300
 - dfbrg 1, corecnf 0x1b, busdf 7, cpmdf 1, plldf 0, pllmf 7, pcidf 3
 - vco_out  528000000, scc_clk  132000000, brg_clk   33000000
 - cpu_clk  330000000, cpm_clk  264000000, bus_clk   66000000

CPU:   MPC8260 (HiP7 Rev 14, Mask 1.0 1K49M) at 330 MHz
Board: MPC8280 Based Remote IO CARD.SLN Technologies Pvt Ltd.
I2C:   ready
DRAM:  512 MB
FLASH: 256.5 MB
*** Warning - bad CRC, using default environment

NIP: 1FFE8A30 XER: 00000000 LR: 1FFE899CC REGS: 1ffa1df0 TRAP: 0700 DAR: 00000000
MSR: 00083002 EE: 0 PR: 0 FP: 1 ME: 1 IR/DR: 00

GPR00: 446BA781 1FFA1EE0 EFFFFFFF 3A858DD6 1FFA9F3C 000080C4 1FFA201D 3D313135 
GPR08: 1FFF0314 NIP: 1FFE9648 XER: 20000000 LR: 1FFE93DC REGS: 1ffa1a68 TRAP: 0700 DAR: 00000000
MSR: 00083002 EE: 0 PR: 0 FP: 1 ME: 1 IR/DR: 00

GPR00: 00000030 1FFA1B58 EFFFFFFF 1FFA1C1C 00000000 00000010 FFFFFFFF 00000030 
GPR08: 00000041 00000000 00000000 00000002 1FFA1B60 FFF7FEFF 1FFFE000 DFFD2000 
GPR16: 1FFF1240 1FFF1214 1FFF127C 1FFA1EA0 00003002 1FFA1DE0 1FFF47F8 1FFA1BD0 
GPR24: 1FFA1C14 00000041 1FFF094C 00000000 1FFF47A8 1FFA1F6C 1FFF$EBBC FFFFFFFF 
Call backtraace: 
Program Check Exception


i am stuck here, dont know where to check if it hangs after 40-60mins.

do help me out in this regard,

Thanks in advance
gurumurthy