tools/openocd: add debugr action

In case of STM32MP157c-dk2 board, there is no flash available. Thus,
the elf binary has to be flashed directly to SRAM before debugging.
To do so, the DBG_FLAGS variable has to be overrided to load the binary
using 'load' gdb command.
The START_ADDR variable is the entrypoint extracted from the elf binary
using objdump tool.
The do_debug function can now be used as usual.

Signed-off-by: Gilles DOFFE <gilles.doffe@savoirfairelinux.com>

dist/tools/openocd/openocd.sh

@@ -51,6 +51,10 @@
 #               DBG:            debugger client command, default: 'gdb -q'
 #               TUI:            if TUI!=null, the -tui option will be used
 #
+# debugr:       debug <elfile>
+#               debug given file on the target but flash it first directly
+#               in RAM.
+#
 # debug-server: starts OpenOCD as GDB server, but does not connect to
 #               to it with any frontend. This might be useful when using
 #               IDEs.
@@ -391,6 +395,14 @@ case "${ACTION}" in
     echo "### Flashing Target ###"
     do_flash "$@"
     ;;
+  debugr)
+    START_ADDR=$(objdump -f $1 | sed '/^$/d' | tail -1 | grep -o "0x[0-9a-fA-F].*")
+    echo "Start address: $START_ADDR"
+    DBG_FLAGS="$DBG_FLAGS \
+        -ex 'load $1' \
+        "
+        do_debug "$@"
+    ;;
   debug)
     echo "### Starting Debugging ###"
     do_debug "$@"