[U-Boot-Users] Debugging U-Boot on 440GP

[Brian Padalino]

Thanks everyone for the replies.  I took a look at those pages and they were
a little helpful.

Some things I am not quite clear about yet:
  - Scott: What you told me was excellent.  I can now debug later functions,
but it doesn't always catch them.
  - Chuck: I didn't realize you read this mailing list.  But either way, are
you telling me to comment out the disabling of the debug registers so the
BDI retains control?
  - Wolfgang: The address of the PC of the 440GP is 0x00000700 or
0x00001400, but that is in my DDR memory.  I guess I am just missing what is
really going on here.

I can single step my way through the display_options functions, and it says
it's trying to write out the serial port (of which it isnt quite connected
yet so I can't quite verify that yet), but if i set a break point at
display_options, and let the CPU continue, it will never return to me.

Am I not being patient enough?  Does debugging just take a significantly
longer time?

For a preemptive question, once I get U-Boot up and running, I had a linux
kernel running on the Ebony dev kit -- do you experts forsee any porting
that will have to be done with that over to the custom platform?

Like I said, any input I can get I would love.  I am very appreciative of
it -- this is the hardest CPU I have had to deal with by far and my first
completely memory managed CPU.

Thank you.

Brian Padalino


-----Original Message-----
From: u-boot-users-admin at lists.sourceforge.net
[mailto:u-boot-users-admin at lists.sourceforge.net]On Behalf Of Wolfgang
Denk
Sent: Tuesday, November 25, 2003 11:39 AM
To: Brian Padalino
Cc: U-Boot Mailing List
Subject: Re: [U-Boot-Users] Debugging U-Boot on 440GP


Dear Brian,

in message <DGEEIPOFGGPOACEFBGGCAECICBAA.bpadalino at perigee.com> you wrote:
> I have a BDI2000 and a custom target board.  I am can successfully connect
> to it and step through single instructions.  I can also set a breakpoint
at
> _start_440, but any breakpoints after that do not get noticed.  I have the
> BDI setup for HARD breakpoints.  Should I have it setup for SOFT instead?

No.

Did you read http://www.denx.de/twiki/bin/view/DULG/DebuggingUBoot
and http://www.denx.de/twiki/bin/view/DULG/DebuggingTricks ?

> What I am seeing is that when I stop the CPU, it's either at 0x700 or
> 0x1400 -- both of which are defined in the kgdb.c file, but I don't know

No. These exception vectors are not defined in  the  kgdb.c,  but  in
start.S; if you look up the addresses in the System.map file you will
find:

	????0700 t ProgramCheck
	...
	????1400 t DataTLBError

Does that ring a bell?

> what they mean.  Can anyone shed any light on the situation for me?  I am
> very new to both the BDI and using gdb (but I learn quickly).

There is probably more interesting information for you in the DULG  -
see URL above.

Best regards,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
In an infinite universe all things are possible, including the possi-
bility that the universe does not exist.
                        - Terry Pratchett, _The Dark Side of the Sun_


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