OpenOCD demo in OpenBMC
This is how to get a "dummy" software only openOCD debug stack running on OpenBMC
Step 1: Include OpenOCD into your local conf.
First thing we need is to add OpenOCD into the scope of our BMC build. Thankfully someone has contributed a OpenOCD recipe into Yocto/OpenEmbbded. Unfortunately the setup is slightly out of date, but we'll update it.
add IMAGE_INSTALL += "openocd" into your conf file.
if you've already exported your conf ($export TEMPLATECONF=meta-ibm/meta-witherspoon/conf)
put it into ../openbmc/build/conf/local.conf
Or:
if you'd like to add this to every build for the machine add it to the
<path_to_machine_conf>/local.conf.sample
an example: ../openbmc/meta-ibm/meta-witherspoon/conf/local.conf.sample
Step 2: update the OpenOCD BB
next we need to update the OpenOCD Bitbake recipe in
../openbmc/meta-openembedded/meta-oe/recipes-devtools/openocd/openocd_git.bb
At the time of writing this, I set it to pull the latest commit from master:
SRCREV_openocd = "7a93c9e087b7cb0444068a3deb506eb127f758f0"
Also you need to update libjaylink, simply update the SRCREV
+SRCREV_libjaylink = "835e45b1a464d1ef053591aacffb3c86a4e12169"
I add the dummy interface so that we can start openOCD stack with no real hardware
EXTRA_OECONF = "--enable-ftdi --disable-doxygen-html --enable-dummy"
Extra_OECONF is where you would add options you’d normally add to the OpenOCD configure step
Step 3: add Conf within QEMU (this should be able to be automated)
for now, we need to locate the installed OpenOCD scripts, which are .tcl files. a simple $ find / *.tcl should be able to point you in the right direction
two examples, where I moved them to my home directory to make them easier to work with.
root@witherspoon:~# cp -r /media/rofs-704e5dc2/usr/share/openocd/scripts/ ~
root@palmetto:~# cp -r /run/initramfs/ro/usr/share/openocd/scripts/ ~
create a new openocd.cfg with the contents
bindto 0.0.0.0
adapter_khz 10
This adapter_khz value is just for dummy debugging, and we are exposing openOCD to the network with bindto 0.0.0.0
Step 4: run OpenOCD with configs
dummy example:
root@witherspoon:~# openocd -f openocd.cfg -f scripts/interface/dummy.cfg -f scripts/board/arm_evaluator7t.cfg