General guidelines for updating FreeRTOS

This file will list the necessary modifications to FreeRTOS package to be used inside PiOS

- include/task.h
add the following declaration: 

	/**
	 * task.h
	 * <PRE>unsigned portBASE_TYPE uxTaskGetRunTime( xTaskHandle xTask );</PRE>
	 *
	 * Returns the run time of selected task
	 *
	 * @param xTask Handle of the task associated with the stack to be checked.
	 * Set xTask to NULL to check the stack of the calling task.
	 *
	 * @return The run time of selected task
	 */
	unsigned portBASE_TYPE uxTaskGetRunTime( xTaskHandle xTask );

it usually is added after the declaration of vTaskGetRunTimeStats.

- task.c
add the following function: 

	#if ( INCLUDE_uxTaskGetRunTime == 1 )
	
	    unsigned portBASE_TYPE uxTaskGetRunTime( xTaskHandle xTask )
	    {
	        unsigned long runTime;
	
	        tskTCB *pxTCB;
	        pxTCB = prvGetTCBFromHandle( xTask );
	        runTime = pxTCB->ulRunTimeCounter;
	        pxTCB->ulRunTimeCounter = 0;
	        return runTime;
	    }
	
	#endif
	/*----------------------------------------------------------*/

it usually is added after the declaration of vTaskGetRunTimeStats.

- portable/MemMang/heap_1.c
following there is the modification done in this revision against the base heap_1.c
The modifications add a currentTOTAL_HEAP_SIZE variable that hold the current heap size,
used instead of the configTOTAL_HEAP_SIZE macro that can be changed by the added
xPortIncreaseHeapSize function.


--- ../op_evo/FreeRTOSV7.4.0/FreeRTOS/Source/portable/MemMang/heap_1.c	2013-04-06 15:04:22.760048534 +0200
+++ ./flight/PiOS/Common/Libraries/FreeRTOS/Source/portable/MemMang/heap_1.c	2013-04-06 14:53:31.828030608 +0200
@@ -92,13 +92,16 @@
 
 #undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE
 
-/* A few bytes might be lost to byte aligning the heap start address. */
-#define configADJUSTED_HEAP_SIZE	( configTOTAL_HEAP_SIZE - portBYTE_ALIGNMENT )
 
 /* Allocate the memory for the heap. */
-static unsigned char ucHeap[ configTOTAL_HEAP_SIZE ];
+static unsigned char ucHeap[ configTOTAL_HEAP_SIZE ]  __attribute__ ((section (".heap")));
 static size_t xNextFreeByte = ( size_t ) 0;
 
+static size_t currentTOTAL_HEAP_SIZE = configTOTAL_HEAP_SIZE;
+
+/* A few bytes might be lost to byte aligning the heap start address. */
+#define configADJUSTED_HEAP_SIZE    (currentTOTAL_HEAP_SIZE - portBYTE_ALIGNMENT)
+
 /*-----------------------------------------------------------*/
 
 void *pvPortMalloc( size_t xWantedSize )
@@ -172,6 +175,12 @@
 {
 	return ( configADJUSTED_HEAP_SIZE - xNextFreeByte );
 }
+/*-----------------------------------------------------------*/
 
-
-
+void xPortIncreaseHeapSize( size_t bytes )
+{
+    vTaskSuspendAll();
+    currentTOTAL_HEAP_SIZE = configTOTAL_HEAP_SIZE + bytes;
+    xTaskResumeAll();
+}
+/*-----------------------------------------------------------*/