RTOS API for bare metal

Provide partial RTOS API for bare metal builds - things that
can be done in a single threaded environment.

Allows more code to work in both RTOS and bare metal builds without
change, and in particular gives easy access to the ability to
efficiently wait for something occurring in interrupt.

Available in bare-metal:
* ThisThread
* osThreadFlagsSet to set flags on main thread (can be set from IRQ)
* EventFlags (can be set from IRQ)
* Semaphores (can be released from IRQ)
* Mutex (dummy implementation)

Not useful:
* ConditionVariable (could only be signalled from 2nd thread)
* RtosTimer (calls in a second thread context)
* Thread

Unimplemented:
* Mail, Queue, MemoryPool

Possible future work:
* ConditionVariableCS to act as IRQ signalled ConditionVariable

Author: kjbracey

UNITTESTS/CMakeLists.txt

@@ -86,6 +86,9 @@ endif(COVERAGE)
 # UNIT TESTS
 ####################
 
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -DUNITTEST")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DUNITTEST")
+
 # Set include dirs.
 set(unittest-includes-base
   "${PROJECT_SOURCE_DIR}/target_h"

UNITTESTS/target_h/rtos/Mutex.h

@@ -18,7 +18,8 @@
 #define __MUTEX_H__
 
 #include <inttypes.h>
-#include "cmsis_os2.h"
+#include "mbed_rtos_types.h"
+#include "mbed_rtos1_types.h"
 
 namespace rtos {
 

UNITTESTS/target_h/mbed_rtos1_types.h renamed to UNITTESTS/target_h/rtos/mbed_rtos1_types.h

@@ -18,7 +18,7 @@
 
 #include "platform/mbed_version.h"
 
-#if MBED_CONF_RTOS_PRESENT
+#if MBED_CONF_RTOS_API_PRESENT
 #include "rtos/rtos.h"
 #endif
 

UNITTESTS/target_h/mbed_rtos_storage.h renamed to UNITTESTS/target_h/rtos/mbed_rtos_storage.h

@@ -26,6 +26,8 @@
 #include "mbed_error.h"
 #include "mbed_assert.h"
 
+#if MBED_CONF_RTOS_PRESENT
+
 namespace rtos {
 
 ConditionVariable::Waiter::Waiter(): sem(0), prev(NULL), next(NULL), in_list(false)
@@ -150,3 +152,5 @@ ConditionVariable::~ConditionVariable()
 }
 
 }
+
+#endif

UNITTESTS/target_h/rtos.h renamed to UNITTESTS/target_h/rtos/rtos.h

@@ -23,12 +23,14 @@
 #define CONDITIONVARIABLE_H
 
 #include <stdint.h>
-#include "cmsis_os.h"
+#include "rtos/mbed_rtos_types.h"
 #include "rtos/Mutex.h"
 #include "rtos/Semaphore.h"
 
 #include "platform/NonCopyable.h"
 
+#if MBED_CONF_RTOS_PRESENT || defined(DOXYGEN_ONLY)
+
 namespace rtos {
 /** \addtogroup rtos */
 /** @{*/
@@ -328,4 +330,6 @@ class ConditionVariable : private mbed::NonCopyable<ConditionVariable> {
 }
 #endif
 
+#endif
+
 /** @}*/

mbed.h

@@ -20,6 +20,8 @@
  * SOFTWARE.
  */
 #include "rtos/EventFlags.h"
+#include "rtos/ThisThread.h"
+#include "mbed_os_timer.h"
 #include <string.h>
 #include "mbed_error.h"
 #include "mbed_assert.h"
@@ -38,27 +40,43 @@ EventFlags::EventFlags(const char *name)
 
 void EventFlags::constructor(const char *name)
 {
+#if MBED_CONF_RTOS_PRESENT
     osEventFlagsAttr_t attr = { 0 };
     attr.name = name ? name : "application_unnamed_event_flags";
     attr.cb_mem = &_obj_mem;
     attr.cb_size = sizeof(_obj_mem);
     _id = osEventFlagsNew(&attr);
     MBED_ASSERT(_id);
+#else
+    _flags = 0;
+#endif
 }
 
 uint32_t EventFlags::set(uint32_t flags)
 {
+#if MBED_CONF_RTOS_PRESENT
     return osEventFlagsSet(_id, flags);
+#else
+    return core_util_atomic_fetch_or_u32(&_flags, flags) | flags;
+#endif
 }
 
 uint32_t EventFlags::clear(uint32_t flags)
 {
+#if MBED_CONF_RTOS_PRESENT
     return osEventFlagsClear(_id, flags);
+#else
+    return core_util_atomic_fetch_and_u32(&_flags, ~flags);
+#endif
 }
 
 uint32_t EventFlags::get() const
 {
+#if MBED_CONF_RTOS_PRESENT
     return osEventFlagsGet(_id);
+#else
+    return core_util_atomic_load_u32(&_flags);
+#endif
 }
 
 uint32_t EventFlags::wait_all(uint32_t flags, uint32_t millisec, bool clear)
@@ -73,7 +91,9 @@ uint32_t EventFlags::wait_any(uint32_t flags, uint32_t millisec, bool clear)
 
 EventFlags::~EventFlags()
 {
+#if MBED_CONF_RTOS_PRESENT
     osEventFlagsDelete(_id);
+#endif
 }
 
 uint32_t EventFlags::wait(uint32_t flags, uint32_t opt, uint32_t millisec, bool clear)
@@ -82,7 +102,24 @@ uint32_t EventFlags::wait(uint32_t flags, uint32_t opt, uint32_t millisec, bool
         opt |= osFlagsNoClear;
     }
 
+#if MBED_CONF_RTOS_PRESENT
     return osEventFlagsWait(_id, flags, opt, millisec);
+#else
+    rtos::internal::flags_check_capture check;
+    check.flags = &_flags;
+    check.options = opt;
+    check.flags_wanted = flags;
+    check.result = 0;
+    check.match = false;
+    mbed::internal::do_timed_sleep_relative_or_forever(millisec, rtos::internal::non_rtos_check_flags, &check);
+    if (check.match) {
+        return check.result;
+    } else if (millisec == 0) {
+        return osErrorResource;
+    } else {
+        return osErrorTimeout;
+    }
+#endif
 }
 
 }

rtos/ConditionVariable.cpp

@@ -23,9 +23,9 @@
 #define EVENT_FLAG_H
 
 #include <stdint.h>
-#include "cmsis_os2.h"
-#include "mbed_rtos1_types.h"
-#include "mbed_rtos_storage.h"
+#include "rtos/mbed_rtos_types.h"
+#include "rtos/mbed_rtos1_types.h"
+#include "rtos/mbed_rtos_storage.h"
 
 #include "platform/NonCopyable.h"
 
@@ -114,8 +114,12 @@ class EventFlags : private mbed::NonCopyable<EventFlags> {
 private:
     void constructor(const char *name = NULL);
     uint32_t wait(uint32_t flags, uint32_t opt, uint32_t millisec, bool clear);
+#if MBED_CONF_RTOS_PRESENT
     osEventFlagsId_t                _id;
     mbed_rtos_storage_event_flags_t _obj_mem;
+#else
+    uint32_t _flags;
+#endif
 };
 
 /** @}*/