util: Add support to auto-flash with Segger J-Link gdbserver

Automatically flash the EC binary when running gdb combined with Segger
J-Link gdbserver and JTrace.

For most code changes, the flashing only takes a 10-20 seconds.

Also updated FPMCU debugging docs to mention the gdbinit.

BRANCH=none
BUG=none
TEST=On machine with dragonclaw attached to J-Trace:
     JLink_Linux_V670e_x86_64/JLinkGDBServerCLExe
       -select USB -device STM32F412CG -endian little -if SWD
       -speed auto -noir -noLocalhostOnly

     BOARD=bloonchipper GDBSERVER=segger
       gdb --ex "target remote 127.0.0.1:2331"

TEST=Same as above, but using CLion for gdb as described in
     https://chromium.googlesource.com/chromiumos/platform/ec/+/refs/heads/master/docs/fingerprint/fingerprint-debugging.md
     and setting USING_CLION=FALSE

Signed-off-by: Tom Hughes <tomhughes@chromium.org>
Change-Id: I88440c0bc8c9b170b239335a33b3c0a0387447f2
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2166143
Reviewed-by: Craig Hesling <hesling@chromium.org>

2 files changed, 59 insertions, 10 deletions

diff --git a/docs/fingerprint/fingerprint-debugging.md b/docs/fingerprint/fingerprint-debugging.md
index f5d9760049..84832e38b6 100644
--- a/docs/fingerprint/fingerprint-debugging.md
+++ b/docs/fingerprint/fingerprint-debugging.md
@@ -27,9 +27,9 @@ used for JTAG and SWD for ARM devices.
 
 ## Software Required
 
-*   [JLink Software] (when using [J-Trace] or other Segger debug probes).
+*   [JLink Software] \(when using [J-Trace] or other Segger debug probes).
 *   Any tool that supports connecting `gdbserver`. This document will assume
-    [CLion].
+    [CLion] and was tested with `JLink_Linux_V670e_x86_64`.
 *   Alternatively, you can use [Ozone] a standalone debugger from Segger.
 
 ## Connecting SWD
@@ -76,7 +76,7 @@ Start the JLink gdbserver for the appropriate MCU type:
 *   Dragontalon / [Nucleo STM32H743ZI]: `STM32H743ZI`
 
 ```bash
-(outside) $ ./JLink_Linux_V660c_x86_64/JLinkGDBServerCLExe -select USB -device STM32F412CG -endian little -if SWD -speed auto -noir -noLocalhostOnly
+(outside) $ ./JLink_Linux_V670e_x86_64/JLinkGDBServerCLExe -select USB -device STM32F412CG -endian little -if SWD -speed auto -noir -noLocalhostOnly
 ```
 
 You should see the port that gdbserver is running on in the output:
@@ -96,13 +96,18 @@ Connected to target
 Waiting for GDB connection...
 ```
 
-In your editor, specify the IP address and port for gdbserver:
+Configure your editor to use this [`.gdbinit`], taking care to set the correct
+environment variables for the `BOARD` and `GDBSERVER` being used. For CLion, if
+you want to use a `.gdbinit` outside of your `HOME` directory, you'll need to
+[configure `~/.gdbinit`].
+
+In your editor, specify the IP address and port for `gdbserver`:
 
 ```
 127.0.0.1:2331
 ```
 
-You will also want to provide the symbol file:
+You will also want to provide the symbol files:
 
 *   RW image: `build/<board>/RW/ec.RW.elf`
 *   RO image: `build/<board>/RO.ec.RO.elf`
@@ -155,6 +160,8 @@ STM32F412 package that does not have the synchronous trace pins, but the
 [CLion Start Remote Debug]: https://www.jetbrains.com/help/clion/remote-debug.html#start-remote-debug
 [Nucleo STM32F412ZG]: https://www.st.com/en/evaluation-tools/nucleo-f412zg.html
 [Nucleo STM32H743ZI]: https://www.st.com/en/evaluation-tools/nucleo-h743zi.html
+[`.gdbinit`]: /util/gdbinit
+[configure `~/.gdbinit`]: https://www.jetbrains.com/help/clion/configuring-debugger-options.html#gdbinit-lldbinit
 
 <!-- Images -->
 
diff --git a/util/gdbinit b/util/gdbinit
index b40137c5a1..f82afa699d 100644
--- a/util/gdbinit
+++ b/util/gdbinit
@@ -26,27 +26,66 @@
 # Environment Setup and Initialization                              #
 #####################################################################
 
+set verbose on
+
+# Start of python code
+
 # Setup environment and pull in object files for the particular BOARD.
 # This requires setting the environment variables mentioned above.
 python
+import distutils.util
 import os
 
 BOARD = os.getenv('BOARD', '')
 GDBSERVER = os.getenv('GDBSERVER', 'openocd')
-GDBPORT = os.getenv('GDBPORT', '3333')
+USING_CLION = distutils.util.strtobool(os.getenv('USING_CLION', 'FALSE'))
+
+if GDBSERVER == "openocd":
+    DEFAULT_GDB_PORT = '3333'
+else:
+    DEFAULT_GDB_PORT = '2331'
+
+GDBPORT = os.getenv('GDBPORT', DEFAULT_GDB_PORT)
+
+EC_DIR = os.getenv('EC_DIR', os.path.join(os.getenv('HOME'),
+                   'chromiumos/src/platform/ec'))
+
+if not os.path.isdir(EC_DIR):
+    print('Error - EC_DIR "' + EC_DIR + '" doesn\'t exist. Aborting.')
+    gdb.execute('quit')
+
+# Monitor commands must be run after connecting to the remote target
+# See https://stackoverflow.com/a/39828850
+# https://youtrack.jetbrains.com/issue/CPP-7322
+# https://sourceware.org/gdb/onlinedocs/gdb/Hooks.html
+post_remote_hook='''
+define target hookpost-remote
+    echo \ Flashing EC binary
+    load {EC_DIR}/build/{BOARD}/ec.obj
+    echo \ Resetting target
+    monitor reset
+    echo \ Halting target
+    monitor halt
+    echo \ Setting breakpoint on main
+    b main
+end\n
+'''.format(BOARD=BOARD, EC_DIR=EC_DIR)
+
 gdb.execute('set $BOARD = "%s"'%BOARD)
 gdb.execute('set $GDBSERVER = "%s"'%GDBSERVER)
 gdb.execute('set $GDBPORT = "%s"'%GDBPORT)
 
-build = 'build/' + BOARD
+build = os.path.join(EC_DIR, 'build', BOARD)
 if BOARD != "":
     if not os.path.isdir(build):
         print('Error - Build path "' + build + '" doesn\'t exist. Aborting.')
         gdb.execute('quit')
 
-    gdb.execute('file ' + build + '/ec.obj')
-    gdb.execute('add-symbol-file ' + build + '/RO/ec.RO.elf')
-    gdb.execute('add-symbol-file ' + build + '/RW/ec.RW.elf')
+    # When using gdb from CLion, this kills gdb.
+    if not USING_CLION:
+        gdb.execute('file ' + os.path.join(build, 'ec.obj'))
+    gdb.execute('add-symbol-file ' + os.path.join(build, 'RO/ec.RO.elf'))
+    gdb.execute('add-symbol-file ' + os.path.join(build, 'RW/ec.RW.elf'))
 
 if GDBSERVER == "openocd":
     gdb.execute('set $GDBSERVER_OPENOCD = 1')
@@ -54,9 +93,12 @@ if GDBSERVER == "openocd":
 elif GDBSERVER == "segger":
     gdb.execute('set $GDBSERVER_OPENOCD = 0')
     gdb.execute('set $GDBSERVER_SEGGER = 1')
+    gdb.execute(post_remote_hook)
 else:
     print('Error - GDBSERVER="' + GDBSERVER + '" is invalid.')
     gdb.execute('quit')
+
+# End of python code
 end
 
 # OpenOCD specific config