[U-Boot-Users] single step flash w/ gdb ocdremote ??

[U-Boot-Users] single step flash w/ gdb ocdremote ??

[Chuck T.]

I'm trying to bring up u-boot/arm Linux on a new board from scratch using a 
Wiggler and ocdremote.  I'm going crazy trying to figure out how to single 
step code in flash.  I can't debug from RAM because u-boot is working when 
loaded into RAM, the problem I'm trying to debug only occurs when u-boot is 
running from flash.

Since ocdremote is only supported on Windoze I've installed cygwin and the 
xscale gnu tools from the macraigor site on an XP system and the 
Windoze/cygwin based Insight debugger is happy to single step code in flash. 
  HOWEVER all of my development is on a Linux platform I'd much rather use 
DDD on Linux.

Remote DDD works fine except for one fatal flaw ... I can't single step 
flash.  It single steps code loaded into RAM.  Since both insight and DDD 
are really just shells talking to gdb talking to ocdremote (gdbserver 
workalike) it seems clear that my problem is I haven't configured gdb to use 
hardware breakpoints while single stepping, but I've searched and searched 
and googled and googled and can't find anything other than hbreak.  What am 
I missing?

[U-Boot-Users] single step flash w/ gdb ocdremote ??

[Andreas Schweigstill]

Dear Chuck!

Chuck T. schrieb:
 > Remote DDD works fine except for one fatal flaw ... I can't single step
 > flash.  It single steps code loaded into RAM.  Since both insight and
 > DDD are really just shells talking to gdb talking to ocdremote
 > (gdbserver workalike) it seems clear that my problem is I haven't
 > configured gdb to use hardware breakpoints while single stepping, but
 > I've searched and searched and googled and googled and can't find
 > anything other than hbreak.  What am I missing?

Unfortunately I don't work with GDB related debuggers but on the
Lauterbach TRACE32 ICD there are two possibilities for setting hardware
breakpoints; first you can specify it by an additional parameter called
/onchip. Second you you define a memory map with the attributes
map.readonly or map.bonchip (which are internally the same). I expect
that similar attributes exist for GDB. Unfortunately not all ARM related
debugging features are implemented properly on GDB; that's why I prefer
Lauterbach debuggers. IIRC they allow also to set software breakpoints
in certain Flash memory devices.

With best regards
Andreas Schweigstill

-- 
Dipl.-Phys. Andreas Schweigstill
Schweigstill IT | Embedded Systems
Schauenburgerstra?e 116, D-24118 Kiel, Germany
Phone: (+49) 431 5606-435, Fax: (+49) 431 5606-436
Mobile: (+49) 171 6921973, Web: http://www.schweigstill.de/