fwgdb.py: Add new script to connect to remote-GDB DUT in firmware

This patch adds the first part of a script that is supposed to make
firmware debugging and control via remote-GDB easier for the masses. The
first features include finding the right PTY to connect to via Servo,
automatically freezing (SIGSTOP) any existing processes (like minicom)
that attach to that terminal, and automatically rebooting the DUT into
GDB mode if necessary. A lot of emphasis is put on smart defaults and
auto-detection to ensure that the tool is as simple to use as possible
and will generally do the "right" thing (e.g. reboot the DUT by default,
unless there is already a GDB session active... this way both "let me
fire up my machine and do some quick test" and "oh, I just hit that rare
crash I was waiting for, let me connect my debugger to analyze it" can
be solved with the default invocation).

I am still planning to add much more to this. There will be
board-specific GDB initialization files to work around some existing
problems and custom GDB commands to make common debugging tasks easier.
This is more of a request for comments to understand design and style
issues in this approach early.

BUG=chrome-os-partner:18390
TEST=Flash /build/<board>/firmware/image.dev.bin to a DUT and connect it
via Servo. Run 'fwgdb' and enjoy not spending an extra 10 minutes trying
to figure out the right command line you need for a GDB invocation.

Change-Id: I6c51123b2be0fef7a7ce9403636733cb38f0c2d8
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/205561

1 files changed, 1 insertions, 0 deletions

diff --git a/bin/fwgdb b/bin/fwgdb
new file mode 120000
index 000000000..72196ceea
--- /dev/null
+++ b/bin/fwgdb
@@ -0,0 +1 @@
+../scripts/wrapper.py
\ No newline at end of file