[U-Boot-Users] Debugging u-boot on a custom 8548 board

[Demke Torsten-atd012]

> ATUM4>mdh 0xfff80000
> 0_fff80000 : 2705 1956 552d 426f 6f74 2031 2e33 2e30  '..VU-Boot 1.3.0
> 
> ATUM4>bi 0xfffff01c
> Breakpoint identification is 0
> ATUM4>go 0xfff80000
> ATUM4>halt
>     Target CPU        : MPC85xx (e500v2 rev.2)
>     Target state      : halted
>     Debug entry cause : COP halt
>     Current PC        : 0xf0000000
>     Current CR        : 0x00000000
>     Current MSR       : 0x00000200
>     Current LR        : 0x00000000
>     Current CCSRBAR   : 0x0_e0000000
> 
This cannot work, as your own memory dump shows (above). 
You have the "magic word" and some ASCCI string at 0xfff80000. 
These are not valid ppc assembler instructions, but the begin of the
u-boot image.
Please check/dump address 0xfffffffc. There should be a valid
jump instruction (see resetvec.S) which jumps to an address 
within a 4kbyte  page at the end of the address space. 
((0xfffff000, _start_e500()).
There will be code that initializes the MMU that you can access
the rest of the flash device(s), including the u-boot image (e.g
cpu_init_f().

> In a nutshell I'm trying to figure out what the pc is doing 
> and why - I can't hit breakpoints nor see any signs of code 
> running. The docs do
> say:
> 
> 4.4.3.3 Boot ROM Location
> The MPC8548E defines the default boot ROM address range to be 
> 8 Mbytes at address 0x0_FF80_0000 to 0x0_FFFF_FFFF. However, 
> which peripheral interface handles these boot ROM accesses 
> can be selected at power on.
> 
> As I said I could be reading this wrong. The 8548 cds code in 
> 1.3 rc1 has:
> 
> #define CFG_BOOT_BLOCK          0xff000000      /* boot TLB block */
> #define CFG_FLASH_BASE          CFG_BOOT_BLOCK  /* start of 
> FLASH 16M */
> #define CFG_FLASH_BANKS_LIST    {0xff800000, CFG_FLASH_BASE}
> 
> Am I reading all this to mean I should load uboot to 
> 0xff800000  - is that wrong ?
This means your Boot flash devices starts is at address 0xff800000, 
not that your boot code starts at this address.

For a start I would use the 8548 cds linker script unchanged,
build your u-boot image, flash it to 0xfff80000 and single-step
with your BDI.


Regards,
Torsten