[ECOS] Help Setting up Abatron bdiGDB to Debug RedBoot

["Herbold, Steve" <sherbold at viadux dot com>]

I have been banging my head trying to get the Abatron bdiGDB JTAG debugger
to help me step through the RedBoot initialization code.  I have tried
following the recommendations from Abatron to get their VTAB entries set up
properly, but almost always end up with "TARGET: communication with debug
handler failed" after stepping past some points.

I have got to believe that someone else is using this debugger for RedBoot.

We are using a custom board with the IXP421 processor, but I have access to
IXDP development platform that behaves same way. I can compile, program
flash, and run (with debugger disconnected) an image on the IXDP development
platform and get RedBoot prompt. 

I am currently basing our cross on the GRG platform as it looked like it had
less junk than the IXDP and was closer to our setup, but may now start with
IXDP and pare it down to match our platform. Our GPIO is of course much
different and my initial foray using the GRG code was to comment out all the
interrupt setup so that our GPIO lines would not cause problems generating
spurious interrupts.  We have 2x16x16 DRAM (64MB), which is different than
either (GRG or IXDP) but I believe I have configured correctly for this, and
was able to run Abatron bdi memory test with pass.


I think some of the problems are that in the initialization memory is being
swapped around (SDRAM to low memory), and MMU and caches being turned on and
flushed. I have tried to set breakpoints past these points in the hope that
funny behavior is just artifact.

Is there a good place to stop (break) the debugger to get the correct vector
values for RedBoot (sym name I can look up in obj dump)?

Is there someplace I can get outline of RedBoot startup sequence?


Any help or suggestions would be appreciated,

Steven J. Herbold
Viadux, Inc. (formerly RC Networks, Inc.)
9890 Towne Centre Drive, Suite 200 
San Diego, CA 92121 
(858) 678-1628 direct
(858) 450-3370 main
(858) 450-3334 fax 

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