openocd.sh: add functions to access board flash address

This allows getting the ROM base address.

It may not be available in the build system directly so better extract it from
openocd. Also openocd is board specific and this address is cpu specific
so would have definition order issue in the build system.

dist/tools/openocd/openocd.sh

@@ -159,6 +159,29 @@ _is_binfile() {
         [[ -z "${firmware_type}" ]] && _has_bin_extension "${firmware}"; }
 }
 
+# Outputs bank info on different lines without the '{}'
+_flash_list() {
+    # Openocd output for 'flash list' is
+    # ....
+    # {name nrf51 base 0 size 0 bus_width 1 chip_width 1} {name nrf51 base 268439552 size 0 bus_width 1 chip_width 1}
+    # ....
+    sh -c "${OPENOCD} \
+            ${OPENOCD_ADAPTER_INIT} \
+            -f '${OPENOCD_CONFIG}' \
+            -c 'flash list' \
+            -c 'shutdown'" 2>&1 | sed -n '/^{.*}$/ {s/\} /\}\n/g;s/[{}]//g;p}'
+}
+
+# Print flash address for 'bank_num' num defaults to 1
+# _flash_address  [bank_num:1]
+_flash_address() {
+    bank_num=${1:-1}
+
+    # extract 'base' value and print as hexadecimal
+    # name nrf51 base 268439552 size 0 bus_width 1 chip_width 1
+    _flash_list | awk "NR==${bank_num}"'{printf "0x%08x\n", $4}'
+}
+
 #
 # now comes the actual actions
 #