tools/openocd: Make verifying flashed image optional

Checksumming flash is not supported on xtensa platform:

Warn : not implemented yet

make: *** [.../RIOT/examples/saul/../../Makefile.include:796: flash] Error 1

cpu/esp32/Makefile.include

@@ -88,4 +88,6 @@ ifneq (,$(filter esp_jtag,$(USEMODULE)))
     -c 'echo "Installing partition table at $(PARTITION_POS)"' \
     -c 'flash write_image erase "$(BINDIR)/partitions.bin" $(PARTITION_POS) bin'
   IMAGE_OFFSET = 0x10000
+  # Flash checksumming not supported on xtensa
+  OPENOCD_SKIP_VERIFY = yes
 endif

dist/tools/openocd/openocd.sh

@@ -113,6 +113,8 @@
 : ${OPENOCD_CMD_RESET_RUN:="-c 'reset run'"}
 # Select core on multi-core processors.
 : ${OPENOCD_CORE:=}
+# Set to any value to skip verifying after flashing.
+: ${OPENOCD_SKIP_VERIFY:=}
 # This is an optional offset to the base address that can be used to flash an
 # image in a different location than it is linked at. This feature can be useful
 # when flashing images for firmware swapping/remapping boot loaders.
@@ -328,6 +330,9 @@ do_flash() {
             exit $RETVAL
         fi
     fi
+    if [ -z "${OPENOCD_SKIP_VERIFY}" ]; then
+        OPENOCD_VERIFY="-c 'verify_image \"${IMAGE_FILE}\" ${IMAGE_OFFSET}'"
+    fi
 
     # In case of binary file, IMAGE_OFFSET should include the flash base address
     # This allows flashing normal binary files without env configuration
@@ -358,7 +363,7 @@ do_flash() {
             ${OPENOCD_PRE_FLASH_CMDS} \
             -c 'flash write_image erase \"${IMAGE_FILE}\" ${IMAGE_OFFSET} ${IMAGE_TYPE}' \
             ${OPENOCD_PRE_VERIFY_CMDS} \
-            -c 'verify_image \"${IMAGE_FILE}\" ${IMAGE_OFFSET}' \
+            ${OPENOCD_VERIFY} \
             -c 'reset run' \
             -c 'shutdown'" &&
     echo 'Done flashing'

makefiles/tools/openocd.inc.mk

@@ -61,6 +61,11 @@ ifneq (,$(OPENOCD_PRE_VERIFY_CMDS))
   $(call target-export-variables,$(OPENOCD_FLASH_TARGETS),OPENOCD_PRE_VERIFY_CMDS)
 endif
 
+ifneq (,$(OPENOCD_SKIP_VERIFY))
+  # Export OPENOCD_SKIP_VERIFY only to the flash/flash-only target
+  $(call target-export-variables,$(OPENOCD_FLASH_TARGETS),OPENOCD_SKIP_VERIFY)
+endif
+
 ifneq (,$(OPENOCD_PRE_FLASH_CMDS))
   # Export OPENOCD_PRE_FLASH_CMDS only to the flash/flash-only targets
   $(call target-export-variables,$(OPENOCD_FLASH_TARGETS),OPENOCD_PRE_FLASH_CMDS)