I've been tasked with porting U-Boot from v1.1.5 to v2013.01 for a custom board based off PPC460SX (AMCC Eiger board which is no longer supported). I'm trying to understand what's going on with my current setup. I'm able to load the u-boot.bin and can see that it's in the correct address location. But I'm running into problems when trying to debug using gdb.
After I telnet to my BDI2000, I can reset and see that I'm moving memory locations with "ti" like so: rare>i Core number : 0 Core state : debug mode Debug entry cause : JTAG stop request Current PC : 0xfffffffc Current CR : 0x82ca2e28 Current MSR : 0x00000000 Current LR : 0xfffff18c rare>ti Core number : 0 Core state : debug mode Debug entry cause : single step Current PC : 0xfffff000 Current CR : 0x82ca2e28 Current MSR : 0x00000000 Current LR : 0xfffff18c rare>ti Core number : 0 Core state : debug mode Debug entry cause : single step Current PC : 0xfffff004 Current CR : 0x82ca2e28 Current MSR : 0x00000000 Current LR : 0xfffff18c rare>ti Core number : 0 Core state : debug mode Debug entry cause : single step Current PC : 0xfffff008 Current CR : 0x82ca2e28 Current MSR : 0x00000000 Current LR : 0xfffff18c rare>
On the BDI, I've build gdb for the powerpc and added -ggdb as well as -fno-schedule-insns -fno_schedule-insns2 #omit-frame-pointer -g to config.mk.
From gdb I run the following:
1. >dir/powerpc-440-linux-gnu-gdb 2. (gdb) set arch powerpc:common 3. (gdb) file u-boot 4. (gdb) target remote ipaddr:2001 (reset via BDI) 5. s or si
My initial step through will get me to "tlbtab_start" in board/dir/init.S. and fail like this:
tlbnxt () at start.S:483 483 tlbnxt: addi r4,r4,1 /* Next TLB */ (gdb) s 484 bdnz rsttlb (gdb) s 504 bl tlbtab /* Get tlbtab pointer */ (gdb) s Cannot access memory at address 0x3f (gdb) s tlbtab () at init.S:43 43 tlbtab_start Cannot access memory at address 0xfffff1f8
If I reset via BDI and step through again I'll receive the "Cannot access memory at address " at what seems to be random spots.
I'm new to software development, especially at such a low level. Any advice you may have would be greatly appreciated, I feel like I'm just spinning my wheels at this point.
Thanks, Greg