ST boards: Fix sleep tracing

Prevent singleton lock if the RTOS is not yet ready.

lp_ticker is used during the RTOS initialization process.
ST lp_ticker implementation calls sleep functions
which in turn attempts to print to the console when sleep tracing
is enabled. Console initialization attempts to lock the singleton mutex.

Author: hugueskamba

rtos/source/TARGET_CORTEX/mbed_boot.c

@@ -64,6 +64,15 @@
 #include "mbed_error.h"
 #include "mbed_mpu_mgmt.h"
 
+#ifdef MBED_CONF_RTOS_PRESENT
+#include "cmsis_os2.h"
+#endif
+
+#ifdef MBED_CONF_RTOS_PRESENT
+extern osMutexId_t singleton_mutex_id;
+extern osMutexAttr_t             singleton_mutex_attr;
+#endif
+
 int main(void);
 static void mbed_cpy_nvic(void);
 
@@ -94,6 +103,9 @@ void mbed_init(void)
 
 void mbed_start(void)
 {
+#ifdef MBED_CONF_RTOS_PRESENT
+    singleton_mutex_id = osMutexNew(&singleton_mutex_attr);
+#endif // MBED_CONF_RTOS_PRESENT
     mbed_toolchain_init();
     mbed_tfm_init();
     mbed_main();

rtos/source/TARGET_CORTEX/mbed_rtos_rtx.c

@@ -68,7 +68,6 @@ MBED_NORETURN void mbed_rtos_start()
     tfm_ns_lock_init();
 #endif // defined(TARGET_TFM) && defined(COMPONENT_NSPE)
 
-    singleton_mutex_id = osMutexNew(&singleton_mutex_attr);
     osThreadId_t result = osThreadNew((osThreadFunc_t)mbed_start, NULL, &_main_thread_attr);
     if ((void *)result == NULL) {
         MBED_ERROR1(MBED_MAKE_ERROR(MBED_MODULE_PLATFORM, MBED_ERROR_CODE_INITIALIZATION_FAILED), "Pre main thread not created", &_main_thread_attr);