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

@@ -64,8 +64,10 @@
 #include "mbed_error.h"
 #include "mbed_mpu_mgmt.h"
 
+
 int main(void);
 static void mbed_cpy_nvic(void);
+void mbed_rtos_init_singleton_mutex(void);
 
 /* Stack limits */
 unsigned char *mbed_stack_isr_start = 0;
@@ -94,6 +96,7 @@ void mbed_init(void)
 
 void mbed_start(void)
 {
+    mbed_rtos_init_singleton_mutex();
     mbed_toolchain_init();
     mbed_tfm_init();
     mbed_main();

rtos/source/TARGET_CORTEX/mbed_rtos_rtx.c

@@ -36,9 +36,14 @@ osThreadAttr_t _main_thread_attr;
 MBED_ALIGN(8) char _main_stack[MBED_CONF_APP_MAIN_STACK_SIZE];
 mbed_rtos_storage_thread_t _main_obj __attribute__((section(".bss.os.thread.cb")));
 
-osMutexId_t               singleton_mutex_id;
+osMutexId_t singleton_mutex_id;
 mbed_rtos_storage_mutex_t singleton_mutex_obj;
-osMutexAttr_t             singleton_mutex_attr;
+const osMutexAttr_t singleton_mutex_attr = {
+    .name = "singleton_mutex",
+    .attr_bits = osMutexRecursive | osMutexPrioInherit | osMutexRobust,
+    .cb_size = sizeof(singleton_mutex_obj),
+    .cb_mem = &singleton_mutex_obj
+};
 
 void mbed_rtos_init()
 {
@@ -47,11 +52,6 @@ void mbed_rtos_init()
 
 MBED_NORETURN void mbed_rtos_start()
 {
-    singleton_mutex_attr.name = "singleton_mutex";
-    singleton_mutex_attr.attr_bits = osMutexRecursive | osMutexPrioInherit | osMutexRobust;
-    singleton_mutex_attr.cb_size = sizeof(singleton_mutex_obj);
-    singleton_mutex_attr.cb_mem = &singleton_mutex_obj;
-
     _main_thread_attr.stack_mem = _main_stack;
     _main_thread_attr.stack_size = sizeof(_main_stack);
     _main_thread_attr.cb_size = sizeof(_main_obj);
@@ -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);
@@ -77,3 +76,8 @@ MBED_NORETURN void mbed_rtos_start()
     osKernelStart();
     MBED_ERROR(MBED_MAKE_ERROR(MBED_MODULE_PLATFORM, MBED_ERROR_CODE_INITIALIZATION_FAILED), "Failed to start RTOS");
 }
+
+void mbed_rtos_init_singleton_mutex(void)
+{
+    singleton_mutex_id = osMutexNew(&singleton_mutex_attr);
+}