[U-Boot] Cannot access memory at address 0xd8013fa8 when using gdb/BDI3000 to debug u-boot

[davis mcpherson]

Ok, I'm updated my u-boot source code to the v2010.12 release and i'm 
still seeing the same behaviour as with the earlier version...

in summary:

early in the boot process, in the start.S file, the L1 DCache is 
configured for use as some initial RAM, the stack is located there, and 
the global data structure, gd_t,  is located there... when I debug my 
u-boot build i can set breakpoints, e.g. in cpu_init_f, and the 
breakpoint is hit and I can single step thru the code, but when the 
return from the function is executed i get the 'Cannot access memory at 
address..." error,  but  apparently the call does return, because I can 
single step on to the next function that is call, board_init_f...

Additionally, if I set a breakpoint in board_init_f, after the 
statement  that initializes the gd_t pointer variable 'gd', and then try 
to print the structure or just examine the memory locations i get the 
same "Cannot access memory at address..." error...

so i'm assuming gdb working with a bdi3000 should be able to access this 
L1Dcache when configured to be used as this initial RAM area for u-boot, 
is this assumption correct?

the code in start.S is coded to be common for all mpc85xx boards (its in 
the arch/powerpc/cpu/mpc85xx directory) with some config options from 
the board specific <board>_config.h file.
My board is custom but modeled after the MPC8548CDS and at least at this 
point of execution I think components common to any MPC8548 board are 
being set up... I left the #define that specifies the address for this 
initial RAM unchanged, 0xe4010000  ( i had changed it to 0xd8010000 when 
i was using 1.3.4, but could see a reason that was required...)

could my bdi3000 config file affect this in any way?  i've attached it 
for reference...

my thanks for your time and any ideas or suggestions are greatly 
appreciated...

davis mcpherson


On 01/22/2011 12:39 PM, Wolfgang Denk wrote:
> Dear davis mcpherson,
>
> In message<4D3B0525.4080107 at gmail.com>  you wrote:
>    
>> I'm trying to get u-boot version 1.3.4 working a custom MPC8548 based
>> board (version 1.1.4 currently works fine on this board so the hardware
>> is known to be good).  I'm encountering the following problem during the
>>      
> Sorry, but I don't even continue reading. v1.3.4 is 2.5 years old,
> i. e. hopelessly obsolete.  Any efforts on this old stuff are only a
> waste of time.
>
> Do yourself (and us) a favour and use current code instead (at least
> v2010.12, or bettter current top of tree from the git repository).
>
> Best regards,
>
> Wolfgang Denk
>
>    

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