Hi,

We are having a problem with porting of Linux.

We are using the Linux kernel image modified to work on an EP8248 (having the MPC8248 Processor) Board. U-boot is used as the bootloader which is working perfectly.We have our board configured the same as the EP8248 board. We have made no changes to the Kernel Image and it crashes. The last message it shows on the console is "Uncompressing Kernel....ok" and the console log_buffer has the following:

"<6>Memory BAT mapping: BAT2=32Mb, BAT3=0Mb, residual: 0Mb. <4>Oops: kernel access of bad area, sig: 11.<4>NIP: 00000000 XER: 00000000 LR: 00000000 SP: 00000000 REGS: c0150000 TRAP: 0000 Not tainted.<4>MSR: 00000000 EE: 0PR: 0 FP: 0 ME:0 IR/DR: 00.<4> TASK = c014f470[0] 'swapper' Last syscall: 0 .<4>last math 00000000 last altivec 00000000.<4>Call backtrace: 00000004 ."

The environment variable bootargs is set as : bootargs=console=ttyS0,115200 root=1f00

But when I changed bootargs to bootargs=console=ttyS0,115200 root=1f00 mem=4M The contents of the log buffer were as follows:

<4><6>Memory BAT mapping: BAT2=4Mb, BAT3=0Mb, residual: 0Mb.<4>Linux version 2.4.27-1.3.1-432 (root@pmcserver) (gcc version 3.3.4) #6 Wed Apr 1315:06:06 IST 2005.<4>On node 0 totae 0 tota1024.<4>zone(0): ...4 pages.........................

But this happened only for once, after that it is consistently showing: <6>Memory BAT mapping: BAT2=16Mb, BAT3=0Mb, residual: 0Mb.<4>Oops: kernel access of bad area, sig: 11.<4>NIP: 00000000 XER: 00000000 LR: 00000000 SP: 00000000 REGS: c0150000 TRAP: 0000 Not tainted.<4>MSR:00000000 EE: 0 PR: 0 FP: 0 ME: 0 IR/DR: 00.<4>TA

The EP8248 Board has the following configurations:

1. 8MB Flash Port Size = 32 Bit Bottom Boot

2. 16MB SDRAM Port Size = 32 Bit

3. EEPROM

4. Memory Map ===================================================================== Memory Region Size Address Range ===================================================================== SDRAM 16MByte 0000_0000 - 00FF_FFFF Flash 8MByte FF80_0000 - FFFF_FFFF

The board we are using has

1. 16MB Flash Port Size = 32 Bit Bottom Boot

2. 32MB SDRAM Port Size = 64 Bit

3. No EEPROM

4. Memory Map ===================================================================== Memory Region Size Address Range

====================================================================== SDRAM 32MByte 0000_0000 - 01FF_FFFF Flash 16MByte FF00_0000 - FFFF_FFFF

The value of the IMMR in HCRW is both boards is configured to 0xF0000000. The value of IMAP_ADDR in linux/arch/ppc/platforms/ep8248.h and u-boot/include/configs/ep8248.h is 0xF0000000. The BD_INFO structure and the values are being passed perfectly from u-boot to Linux. The cmd_start and cmd_end are also perfect - verified using the memory dump command in u-boot.

The Kernel start address is 0xC0000000.

We have performed RAM test through u-boot and it has passed it.

We would be grateful if you could throw more light on where we are going wrong and help us successful port Linux. If you require any more info I would be more than glad to provide you with the same.

Thanks and Regards Vikrant

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