examples: Run TF-M example on CMSIS/ThreadX

Allow the TF-M example to be run via the CMSIS-RTOSv2/ThreadX adaptation
layer.

Signed-off-by: David Horstmann <david.horstmann@arm.com>

templates/examples/tf-m/CMakeLists.txt

@@ -5,7 +5,7 @@
 
 set(example tf-m)
 set(supported_platforms corstone-300 corstone-310)
-set(supported_rtoses cmsis-rtx)
+set(supported_rtoses cmsis-rtx cmsis-threadx)
 
 foreach(platform IN LISTS supported_platforms)
     get_tfm_target_platform_variables(${platform})
@@ -33,5 +33,8 @@ foreach(platform IN LISTS supported_platforms)
             firmware_update.log
             DESTINATION ${example_dir}
         )
+        if(rtos STREQUAL "cmsis-threadx")
+            file(COPY threadx-config DESTINATION ${example_dir})
+        endif()
     endforeach()
 endforeach()

templates/examples/tf-m/threadx-config/tx_user.h

+/*
+ * Copyright (c) 2022, Arm Limited and Contributors. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef TX_USER_H
+#define TX_USER_H
+
+/* Armv8-M runs in non-secure mode only when TrustZone is configured */
+#define TX_SINGLE_MODE_NON_SECURE
+
+/* Prevent tx_kernel_enter() from scheduling threads so that the CMSIS layer
+ * can create objects before the scheduler is started. */
+#define TX_PORT_SPECIFIC_PRE_SCHEDULER_INITIALIZATION return;
+
+/* Allow 64 priorities to allow space for all of the possible CMSIS-RTOSv2
+ * priorities to be represented. */
+#define TX_MAX_PRIORITIES 64
+
+/* Add special thread extension. */
+#define TX_THREAD_USER_EXTENSION VOID *tx_cmsis_extension;
+
+/* Increase default thread stack size to 1024 bytes to prevent stack
+ * overflow. */
+#define OS_STACK_SIZE 1024
+
+#endif