[U-Boot-Users] problem when running the bootm command

[Jerry Van Baren]

Erez Koelewyn wrote:
> Hi,
> 
> I am using the M5282EVB configuration. I have come across the
> following problem: I load a compressed linux image into address 400000
> (I leave enough
>  room for it to be decompressed at address 100000).
>  I then run -> bootm 400000
>  This works fine (the image is decompressed at address 100000 and runs
> correctly).
> 
>  Now I reset the board, download the compressed image again (using
>  iminfo to very it's header is there and correct) and again I run ->
>  bootm 400000
> 
>  This time I get an exception (this happens consistently until I
>  program U-Boot again into FLASH, at which time I can again use bootm
>  successfully only once):
> 
>  -> bootm 400000
>  ## Booting image at 00400000 ...
>    Image Name:
>    Image Type:   M68K Linux Standalone Program (gzip compressed)
>    Data Size:    1249874 Bytes =  1.2 MB
>    Load Address: 00100000
>    Entry Point:  00100000
>    Verifying Checksum ... OK
>    Uncompressing Standalone Application ...
> 
>  *** Unexpected exception ***
>  Vector Number: 3  Format: 04  Fault Status: 4
> 
>  PC: 00fe5d48    SR: 00002704    SP: 00f9155c
>  D0: 00000000    D1: 00000000    D2: 00000000    D3: 0000011a
>  D4: 00000000    D5: 00000000    D6: 004000d8    D7: 00fa1f90
>  A0: 00000009    A1: 00fac8e0    A2: 00fa28e0    A3: 00f91afe
>  A4: 00fa2928    A5: 00ff7600    A6: 00f91ad4
> 
>  *** Please Reset Board! ***
> 
> The problem cannot e related to overwriting critical areas in RAM
> because I don't overwrite U-Boot's region or the region where I store
> the packaged image.
> 
> Did anyone come across this problem
> 
>  Thanks,
>  Erez

I'm clueless but that never stopped me from guessing.  ;-)

It sounds like your linux image is scribbling in flash, messing up 
u-boot (but not fatally).  Do you have a flash file system configured in 
your linux image?  Any other reason your linux image would overwrite 
flash?  If you dump the end portion of the *flash* u-boot image before 
and after the successful linux boot, does it show corruption?

If that isn't the problem the follow up question is: what is the 
unexpected exception vector number 3, what is the meaning of the PC 
(where the exception occurred), what does the stack tell you when you 
dump it?

Good luck,
gvb