Unable to Read PPC440EPx Board ID thru Board Control and Status Registers (BCSR)

[Dell Query]

Hi,

I am creating a simple program which will try to read the board ID of the PPC440EPx thru BCSR but when I load it, it gives me "Data Read PLB Error". 

I am not sure if I missed out something.

I would really appreciate it if somebody could help me on this.

I have posted the source code below, as well as the complete message.

Many thanks!

SOURCE CODE:
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#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <linux/i2c.h>
#include <linux/i2c-id.h>
#include <asm/ocp.h>
#include <asm/ibm4xx.h>

MODULE_LICENSE("GPL");

#define BCSR_BASE   0xC0002000
#define BCSR0       0
#define BCSR1       1
#define BCSR2       2

#define USER_LED    0x2
#define SIZE_TO_MAP 10

#define LED_ON      0

uint __iomem *bcsrbase = NULL;

static int __init initFunction(void) {
   uint tmp;
   printk("<1> Calling init function.\n");
   printk("<1> bcsrbase value %p...\n",bcsrbase);
   printk("<1> Remapping %x...\n",BCSR_BASE);
   /*map*/
   bcsrbase = ioremap(BCSR_BASE, SIZE_TO_MAP);
   printk("<1> bcsrbase new value %p...\n",bcsrbase);
   /*read value*/
   /*based on PPC440EPx document, BCSR0 is BoardID*/
   tmp = in_be32(bcsrbase + BCSR0 /* BCSR0 */);
   printk("<1> BCSR0 %x...\n",tmp);
   /*try to output something*/
   //out_be32(bcsrbase , /*LED_ON*/);
   return 0;
}
static void __exit cleanupFunction(void) {
   printk("<1> Calling cleanup function.\n");
   /*unmap*/
   iounmap(bcsrbase);
}

module_init(initFunction);
module_exit(cleanupFunction);
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ERROR MESSAGE:
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/mnt/flash_fs/var/ftp # insmod bcsr.ko
 Calling init function.
 bcsrbase value 00000000...
 Remapping c0002000...
 bcsrbase new value d50fe000...
Machine check in kernel mode.
Data Read PLB Error
OPB to PLB3: BSTAT= 0x00000000
PLB3 to PLB4: BEAR=0xffffffffffff7fff BESR0=0x00000000 BESR1=0x00000000
PLB4 to PLB3: BEAR=0xfd7fffffffffffff BESR0=0x00000000 BESR1=0x00000000
PLB3 to OPB: BEAR=0xffffffff BESR0=0x00000000 BESR1=0x00000000
PLB3 arbiter: BEAR=0xbfffffef ACR=0x90000000 BESR=0x00000000
PLB4 to OPB1: BEAR=0x0000000efffbfffb BESR0=0x00000000 BESR1=0x00000000
PLB40 Arbiter: BEAR=0x00000000c0002000 ACR=0xde000000 BESR0=0x0f000000
PLB41 Arbiter: BEAR=0xfffffffffffffffa ACR=0xdf000000 BESR0=0x00000000
POB0: BEAR=0xc27e3194ffffffff BESR0=0x00000000 BESR1=0x00000000
OPB0: BEAR=0x0000000000000000 BSTAT=0x00000000
Oops: machine check, sig: 7 [#1]
NIP: D50FC07C LR: D50FC070 CTR: 00000000
REGS: c02bcf50 TRAP: 0202   Not tainted  (2.6.21-rc4)
MSR: 00029000 <EE,ME>  CR: 24004022  XER: 00000000
TASK = c05fe490[115] 'insmod' THREAD: cdc6c000
GPR00: D50FC070 CDC6DE80 C05FE490 00000023 0A00C100 00000001 00000000 00000031
GPR08: 00000000 D50FE000 000017E4 C0290000 04004022 1016F458 00000000 00000000
GPR16: 00000000 00000000 00000030 00000030 00000124 D51132BC 00000000 C0035E2C
GPR24: 00000022 D5108000 00000022 D50F7500 CF68A21C D50F0000 CF68A000 C0279CEC
NIP [D50FC07C] initFunction+0x7c/0x128 [bcsr]
LR [D50FC070] initFunction+0x70/0x128 [bcsr]
Call Trace:
[CDC6DE80] [D50FC070] initFunction+0x70/0x128 [bcsr] (unreliable)
[CDC6DEA0] [C003731C] sys_init_module+0xe4/0x1458
[CDC6DF40] [C0001AC4] ret_from_syscall+0x0/0x3c
Instruction dump:
60842000 38600000 48000065 7c601b78 3c60d50f 7c040378 386370e8 901d76a0
4800003d 813d76a0 7c0004ac 80890000 <0c040000> 4c00012c 3c60d50f 38637108
Bus error
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