Add Rom config info getter and rom defines

* MBED_ROM_START = start of current rom (independent of BL modes)
 * MBED_ROM_SIZE = size of current rom (independent of BL modes)

tools/config/__init__.py

@@ -593,6 +593,25 @@ class Config(object):
                 continue
         raise ConfigException(exception_text)
 
+    @property
+    def rom(self):
+        """Get rom information as a pair of start_addr, size"""
+        # Override rom_start/rom_size
+        #
+        # This is usually done for a target which:
+        # 1. Doesn't support CMSIS pack, or
+        # 2. Supports TrustZone and user needs to change its flash partition
+        cmsis_part = self._get_cmsis_part()
+        rom_start, rom_size = self._get_mem_specs(
+            ["IROM1", "PROGRAM_FLASH"],
+            cmsis_part,
+            "Not enough information in CMSIS packs to build a bootloader "
+            "project"
+        )
+        rom_start = int(getattr(self.target, "mbed_rom_start", False) or rom_start, 0)
+        rom_size = int(getattr(self.target, "mbed_rom_size", False) or rom_size, 0)
+        return (rom_start, rom_size)
+
     @property
     def ram_regions(self):
         """Generate a list of ram regions from the config"""
@@ -614,30 +633,16 @@ class Config(object):
     @property
     def regions(self):
         """Generate a list of regions from the config"""
-        cmsis_part = self._get_cmsis_part()
         if  ((self.target.bootloader_img or self.target.restrict_size) and
              (self.target.mbed_app_start or self.target.mbed_app_size)):
             raise ConfigException(
                 "target.bootloader_img and target.restirct_size are "
                 "incompatible with target.mbed_app_start and "
                 "target.mbed_app_size")
-        rom_start, rom_size = self._get_mem_specs(
-            ["IROM1", "PROMGRAM_FLASH"],
-            cmsis_part,
-            "Not enough information in CMSIS packs to build a bootloader project"
-        )
-        # Override rom_start/rom_size
-        #
-        # This is usually done for a target which:
-        # 1. Doesn't support CMSIS pack, or
-        # 2. Supports TrustZone and user needs to change its flash partition
-        rom_start = int(getattr(self.target, "mbed_rom_start", False) or rom_start, 0)
-        rom_size = int(getattr(self.target, "mbed_rom_size", False) or rom_size, 0)
-
         if self.target.bootloader_img or self.target.restrict_size:
-            return self._generate_bootloader_build(rom_start, rom_size)
+            return self._generate_bootloader_build(*self.rom)
         else:
-            return self._generate_linker_overrides(rom_start, rom_size)
+            return self._generate_linker_overrides(*self.rom)
 
     @staticmethod
     def header_member_size(member):

tools/toolchains/__init__.py

@@ -27,6 +27,7 @@ from os.path import (join, splitext, exists, relpath, dirname, basename, split,
 from itertools import chain
 from inspect import getmro
 from copy import deepcopy
+from collections import namedtuple
 from abc import ABCMeta, abstractmethod
 from distutils.spawn import find_executable
 from multiprocessing import Pool, cpu_count
@@ -39,6 +40,7 @@ from ..settings import MBED_ORG_USER, PRINT_COMPILER_OUTPUT_AS_LINK
 from .. import hooks
 from ..notifier.term import TerminalNotifier
 from ..memap import MemapParser
+from ..config import ConfigException
 
 
 #Disables multiprocessing if set to higher number than the host machine CPUs
@@ -1184,9 +1186,9 @@ class mbedToolchain:
 
         return None
 
-    def _add_defines_from_region(self, region):
-        for define in [(region.name.upper() + "_ADDR", region.start),
-                        (region.name.upper() + "_SIZE", region.size)]:
+    def _add_defines_from_region(self, region, suffixes=['_ADDR', '_SIZE']):
+        for define in [(region.name.upper() + suffixes[0], region.start),
+                       (region.name.upper() + suffixes[1], region.size)]:
             define_string = "-D%s=0x%x" %  define
             self.cc.append(define_string)
             self.cppc.append(define_string)
@@ -1223,6 +1225,15 @@ class mbedToolchain:
                 ", ".join(r.name for r in regions)
             ))
             self._add_all_regions(regions, "MBED_RAM")
+        try:
+            rom_start, rom_size = self.config.rom
+            Region = namedtuple("Region", "name start size")
+            self._add_defines_from_region(
+                Region("MBED_ROM", rom_start, rom_size),
+                suffixes=["_START", "_SIZE"]
+            )
+        except ConfigException:
+            pass
 
     # Set the configuration data
     def set_config_data(self, config_data):