PSOC6: refactor M0 image merging, enable export to makefile

Rename the existing PSoC-specific m0_core_img key in targets.json
as a more generic hex_filename key. Update makefile exporter to select
the subset of resources.hex_files matching the hex_filename value.
Without this fix, multiple prebuilt CM0+ hex files are found in the
target resources and erroneously passed to the srec_cat tool.

The fix is generic so other targets that need post-build hex merging
can use this key to pass the correct image to srecord tool.

The fix also removes sub_target key: instead, rely hex_filename json
key to detect if the hex image merging needs to be done.
The sub_target is not used in mbed-os codebase for anything else.

It is possible to override the hex file name in mbed_app.json:
{
  "target_overrides": {
    "*": {
      "target.hex_filename": "my_custom_m0_image.hex"
    }
}

Author: vmedcy

targets/targets.json

@@ -7837,12 +7837,11 @@
     },
     "FUTURE_SEQUANA": {
         "inherits": ["MCU_PSOC6_M4"],
-        "sub_target": "FUTURE_SEQUANA_M0",
         "supported_form_factors": ["ARDUINO"],
         "extra_labels_add": ["CY8C63XX", "CORDIO"],
         "macros_add": ["CY8C6347BZI_BLD53"],
         "detect_code": ["6000"],
-        "m0_core_img": "psoc63_m0_default_1.02.hex",
+        "hex_filename": "psoc63_m0_default_1.02.hex",
         "post_binary_hook": {
             "function": "PSOC6Code.complete"
         },
@@ -7892,12 +7891,11 @@
     },
     "FUTURE_SEQUANA_PSA": {
         "inherits": ["NSPE_Target", "FUTURE_SEQUANA"],
-        "sub_target": "FUTURE_SEQUANA_M0_PSA",
         "extra_labels_add": ["PSA"],
         "extra_labels_remove": ["CORDIO"],
         "components_add": ["SPM_MAILBOX"],
         "macros_add": ["PSOC6_DYNSRM_DISABLE=1", "MBEDTLS_PSA_CRYPTO_C"],
-        "m0_core_img": "psa_release_1.0.hex",
+        "hex_filename": "psa_release_1.0.hex",
         "overrides": {
             "secure-rom-start": "0x10000000",
             "secure-rom-size": "0x80000",

tools/export/makefile/__init__.py

@@ -54,7 +54,8 @@ class Makefile(Exporter):
         "MCU_NRF51Code.binary_hook",
         "TEENSY3_1Code.binary_hook",
         "LPCTargetCode.lpc_patch",
-        "LPC4088Code.binary_hook"
+        "LPC4088Code.binary_hook",
+        "PSOC6Code.complete"
     ])
 
     @classmethod
@@ -83,6 +84,11 @@ def generate(self):
         sys_libs = [self.prepare_sys_lib(lib) for lib
                     in self.toolchain.sys_libs]
 
+        hex_files = self.resources.hex_files
+        if hasattr(self.toolchain.target, 'hex_filename'):
+            hex_filename = self.toolchain.target.hex_filename
+            hex_files = list(f for f in hex_files if basename(f) == hex_filename)
+
         ctx = {
             'name': self.project_name,
             'to_be_compiled': to_be_compiled,
@@ -92,7 +98,7 @@ def generate(self):
             'linker_script': self.resources.linker_script,
             'libraries': libraries,
             'ld_sys_libs': sys_libs,
-            'hex_files': self.resources.hex_files,
+            'hex_files': hex_files,
             'vpath': (["../../.."]
                       if (basename(dirname(dirname(self.export_dir)))
                           == "projectfiles")

tools/targets/PSOC6.py

@@ -1,5 +1,6 @@
 #
 # Copyright (c) 2017-2018 Future Electronics
+# Copyright (c) 2018-2019 Cypress Semiconductor Corporation
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -114,18 +115,18 @@ def complete_func(message_func, elf0, hexf0, hexf1=None, dest=None):
     ihex.write_hex_file(dest if dest else hexf0, write_start_addr=False, byte_count=64)
 
 # Find Cortex M0 image.
-def find_cm0_image(toolchain, resources, elf, hexf):
+def find_cm0_image(toolchain, resources, elf, hexf, hex_filename):
     # Locate user-specified image
     from tools.resources import FileType
     hex_files = resources.get_file_paths(FileType.HEX)
-    m0hexf = next((f for f in hex_files if os.path.basename(f) == toolchain.target.m0_core_img), None)
+    m0hexf = next((f for f in hex_files if os.path.basename(f) == hex_filename), None)
     if toolchain.target.name.endswith('_PSA'):
         m0hexf = next((f for f in hex_files if os.path.basename(f) == os.path.basename(hexf)), m0hexf)
 
     if m0hexf:
         toolchain.notify.debug("M0 core image file found: %s." % os.path.basename(m0hexf))
     else:
-        toolchain.notify.debug("M0 core hex image file %s not found. Aborting." % toolchain.target.m0_core_img)
+        toolchain.notify.debug("M0 core hex image file %s not found. Aborting." % hex_filename)
         raise ConfigException("Required M0 core hex image not found.")
 
     return m0hexf

tools/targets/__init__.py

@@ -583,10 +583,11 @@ class PSOC6Code:
     @staticmethod
     def complete(t_self, resources, elf, binf):
         from tools.targets.PSOC6 import complete as psoc6_complete
-        if hasattr(t_self.target, "sub_target"):
+        if hasattr(t_self.target, "hex_filename"):
+            hex_filename = t_self.target.hex_filename
             # Completing main image involves merging M0 image.
             from tools.targets.PSOC6 import find_cm0_image
-            m0hexf = find_cm0_image(t_self, resources, elf, binf)
+            m0hexf = find_cm0_image(t_self, resources, elf, binf, hex_filename)
             psoc6_complete(t_self, elf, binf, m0hexf)
         else:
             psoc6_complete(t_self, elf, binf)