Remove Cortex-A mbed OS 5 support

targets/targets.json

@@ -1926,7 +1926,7 @@
         "inherits": ["Target"],
         "device_has": ["ANALOGIN", "CAN", "ERROR_PATTERN", "ETHERNET", "I2C", "I2CSLAVE", "I2C_ASYNCH", "INTERRUPTIN", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_ASYNCH", "SERIAL_FC", "SPI", "SPISLAVE", "SPI_ASYNCH", "STDIO_MESSAGES"],
         "features": ["LWIP"],
-        "release_versions": ["2", "5"]
+        "release_versions": ["2"]
     },
     "VK_RZ_A1H": {
         "inherits": ["Target"],
@@ -1938,7 +1938,7 @@
         "device_has": ["ANALOGIN", "CAN", "ERROR_PATTERN", "ETHERNET", "I2C", "I2CSLAVE", "INTERRUPTIN", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_FC", "SPI", "SPISLAVE", "STDIO_MESSAGES"],
         "features": ["LWIP"],
         "default_lib": "std",
-        "release_versions": ["2", "5"]
+        "release_versions": ["2"]
     },
     "MAXWSNENV": {
         "inherits": ["Target"],

tools/build_api.py

@@ -514,7 +514,14 @@ def build_project(src_paths, build_path, target, toolchain_name,
         if  (hasattr(toolchain.target, "release_versions") and
              "5" not in toolchain.target.release_versions and
              "rtos" in toolchain.config.lib_config_data):
-            raise NotSupportedException("Target does not support mbed OS 5")
+            if "Cortex-A" in toolchain.target.core:
+                raise NotSupportedException(
+                    ("%s Will be supported in mbed OS 5.6. "
+                     "To use the %s, please checkout the mbed OS 5.4 release branch. "
+                     "See https://developer.mbed.org/platforms/Renesas-GR-PEACH/#important-notice "
+                     "for more information") % (toolchain.target.name, toolchain.target.name))
+            else:
+                raise NotSupportedException("Target does not support mbed OS 5")
 
         # Change linker script if specified
         if linker_script is not None: