Task should be not blocked if flag which are we waiting for has been …

…already set (ARM-software#86)

- added task notification if unrequested flag is set in order to mark FreeRTOS task notify state as taskNOTIFICATION_RECEIVED again

CMSIS/RTOS2/FreeRTOS/Source/cmsis_os2.c

@@ -993,10 +993,12 @@ uint32_t osThreadFlagsGet (void) {
   Wait for one or more Thread Flags of the current running thread to become signaled.
 */
 uint32_t osThreadFlagsWait (uint32_t flags, uint32_t options, uint32_t timeout) {
+  TaskHandle_t hTask;
   uint32_t rflags, nval;
   uint32_t clear;
   TickType_t t0, td, tout;
   BaseType_t rval;
+  BaseType_t notify = pdFALSE;
 
   if (IRQ_Context() != 0U) {
     rflags = (uint32_t)osErrorISR;
@@ -1022,6 +1024,11 @@ uint32_t osThreadFlagsWait (uint32_t flags, uint32_t options, uint32_t timeout)
         rflags &= flags;
         rflags |= nval;
 
+        if ((rflags & ~flags) != 0) {
+          /* Other flags already set, notify task to change its state */
+          notify = pdTRUE;
+        }
+
         if ((options & osFlagsWaitAll) == osFlagsWaitAll) {
           if ((flags & rflags) == flags) {
             break;
@@ -1063,6 +1070,15 @@ uint32_t osThreadFlagsWait (uint32_t flags, uint32_t options, uint32_t timeout)
     while (rval != pdFAIL);
   }
 
+  if (notify == pdTRUE) {
+    hTask = xTaskGetCurrentTaskHandle();
+
+    /* Ensure task is already notified without changing existing flags */
+    if (xTaskNotify(hTask, 0, eNoAction) != pdPASS) {
+      rflags = (uint32_t)osError;
+    }
+  }
+
   /* Return flags before clearing */
   return (rflags);
 }