lib: system: freertos: mutex: change to use atomic_int instead of fre…

…ertos construct

As freertos does not seem to provide way to statically initialize semaphore,
use atomic int which provides this functionality.

Signed-off-by: Ben Levinsky <ben.levinsky@xilinx.com>

lib/system/freertos/mutex.h

@@ -16,24 +16,22 @@
 #ifndef __METAL_FREERTOS_MUTEX__H__
 #define __METAL_FREERTOS_MUTEX__H__
 
-#include <metal/assert.h>
-#include "FreeRTOS.h"
-#include "semphr.h"
-
+#include <metal/atomic.h>
+#include <stdlib.h>
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 typedef struct {
-	SemaphoreHandle_t m;
+	atomic_int v;
 } metal_mutex_t;
 
 /*
  * METAL_MUTEX_INIT - used for initializing an mutex elmenet in a static struct
  * or global
  */
-#define METAL_MUTEX_INIT(m) { NULL }
+#define METAL_MUTEX_INIT(m)		{ ATOMIC_VAR_INIT(0) }
 /*
  * METAL_MUTEX_DEFINE - used for defining and initializing a global or
  * static singleton mutex
@@ -42,40 +40,34 @@ typedef struct {
 
 static inline void __metal_mutex_init(metal_mutex_t *mutex)
 {
-	metal_assert(mutex);
-	mutex->m = xSemaphoreCreateMutex();
-	metal_assert(mutex->m != NULL);
+	atomic_store(&mutex->v, 0);
 }
 
 static inline void __metal_mutex_deinit(metal_mutex_t *mutex)
 {
-	metal_assert(mutex && mutex->m != NULL);
-	vSemaphoreDelete(mutex->m);
-	mutex->m=NULL;
+	(void)mutex;
 }
 
 static inline int __metal_mutex_try_acquire(metal_mutex_t *mutex)
 {
-	metal_assert(mutex && mutex->m != NULL);
-	return xSemaphoreTake(mutex->m, ( TickType_t ) 0 );
+	return 1 - atomic_flag_test_and_set(&mutex->v);
 }
 
 static inline void __metal_mutex_acquire(metal_mutex_t *mutex)
 {
-	metal_assert(mutex && mutex->m != NULL);
-	xSemaphoreTake(mutex->m, portMAX_DELAY);
+	while (atomic_flag_test_and_set(&mutex->v)) {
+		;
+	}
 }
 
 static inline void __metal_mutex_release(metal_mutex_t *mutex)
 {
-	metal_assert(mutex && mutex->m != NULL);
-	xSemaphoreGive(mutex->m);
+	atomic_flag_clear(&mutex->v);
 }
 
 static inline int __metal_mutex_is_acquired(metal_mutex_t *mutex)
 {
-	metal_assert(mutex && mutex->m != NULL);
-	return (NULL == xSemaphoreGetMutexHolder(mutex->m)) ? 0 : 1;
+	return atomic_load(&mutex->v);
 }
 
 #ifdef __cplusplus