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

[robert lazarski]

On 9/21/07, Demke Torsten-atd012 <torsten.demke at motorola.com> wrote:
>

Thanks all, I can now debug! Please see below...

> > 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().

Seems so clear now - thank you very much for the kind help.

> > 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.
>

So I executed:

/home/iksrazal/eldk2/usr/bin> ./powerpc-linux-objdump -D
/home/iksrazal/u-boot/u-boot > ~/u-boot.mydump

For clearer debugging, I compiled u-boot with:

OPTFLAGS= -Os -fno-schedule-insns -fno-schedule-insns2

After a reset in the bdi, I can now single step via 'ti' until:

ATUM>ti
    Target CPU        : MPC85xx (e500v2 rev.2)
    Target state      : halted
    Debug entry cause : single step
    Current PC        : 0xfffff20c
    Current CR        : 0x00000000
    Current MSR       : 0x00000200
    Current LR        : 0xfffff0b4
    Current CCSRBAR   : 0x0_e0000000
ATUM>ti
    Target CPU        : MPC85xx (e500v2 rev.2)
    Target state      : halted
    Debug entry cause : COP halt
    Current PC        : 0xfff80e00
    Current CR        : 0x00000000
    Current MSR       : 0x00000000
    Current LR        : 0xfffff210
    Current CCSRBAR   : 0x0_e000000

Where in ~/u-boot.mydump :

fffff208 <tlb1_entry>:
fffff208:       7c 28 02 a6     mflr    r1
fffff20c:       48 00 00 b9     bl      fffff2c4 <tlb1_entry+0xbc>

And:

fff80e00 <InstructionTLBError>

fffff20c is seemingly my init.S code - how can I find out for sure?
The first lines I have are:

#define entry_start \
        mflr    r1      ;       \
        bl      0f      ;

Thanks all more than words can tell,
Robert