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

Demke Torsten-atd012
2007-09-21T07:25:43Z

> -----Original Message-----
> From: u-boot-users-bounces at lists.sourceforge.net
> [mailto:u-boot-users-bounces at lists.sourceforge.net] On Behalf
> Of Erik Christiansen
> Sent: Freitag, 21. September 2007 08:59
> To: u-boot-users at lists.sourceforge.net
> Subject: Re: [U-Boot-Users] Debugging u-boot on a custom 8548 board
>
> On Fri, Sep 21, 2007 at 07:14:20AM +0100, Demke Torsten-atd012 wrote:
> >
> > > 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().
>
> Errm, having just done an initial build for the ep8248e, I
> first looked in the generated u-boot.map file. In my case, it says:
>
> .text
> ...
> 0xfff00100 _start
And...?
_start is at 0xfff00100 at my board too, but go 0xfff01000
will probably fail, because this address is outside the 4K page and
MMU is not properly configured...

see start.S:
...
_start_e500:
...
/* Jump out of the last 4K page and continue to 'normal' start */
1: bl 3f
b _start
...

Regards,
Torsten

> so I'm planning to "go 0xfff00100", and if that doesn't do
> it, then "go 0x100", because CS0 is then hopefully mapping
> flash to put _start at the reset vector, so it'll work at
> power-on. (Just an optimistic WAG at this
> stage.)
>
> Anyway, what does robert's u-boot.map say?
>
> Erik
>
> (Sorry, just subscribed, and it's Friday, so couldn't resist
> rashly chiming in. :)
>
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