OP-900 Updated howto_upgrade.txt doc

+review OPReview-435

flight/PiOS/Common/Libraries/FreeRTOS/howto_upgrade.txt

@@ -2,6 +2,16 @@ General guidelines for updating FreeRTOS
 
 This file will list the necessary modifications to FreeRTOS package to be used inside PiOS
 
+Brief list of modifications: 
+*Add function to get task run time;
+*Modified heap_1.c to allow for different alignment for stack and generic malloc;
+*Allow heap_1.c for modification of max heap size at runtime;
+*use section ".heap" for heap.
+
+
+
+
+
 - include/task.h
 add the following declaration: 
 
@@ -41,16 +51,24 @@ add the following function:
 
 it usually is added after the declaration of vTaskGetRunTimeStats.
 
+- STM32F1XX/Libraries/FreeRTOS/Source/portable/GCC/ARM_CM3/portmacro.h
+add the following define for 
+
+#define portBYTE_HEAP_ALIGNMENT     4 // this value is used to allocate heap
+
+
+
+
 - 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.
-
+Also it allows for configurable aligments for Heap and Stack allocations.
 
 --- ../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
++++ ./flight/PiOS/Common/Libraries/FreeRTOS/Source/portable/MemMang/heap_1.c	2013-04-08 02:23:01.649194752 +0200
-@@ -92,13 +92,16 @@
+@@ -92,26 +92,30 @@
  
  #undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE
  
@@ -63,14 +81,54 @@ xPortIncreaseHeapSize function.
  static size_t xNextFreeByte = ( size_t ) 0;
  
 +static size_t currentTOTAL_HEAP_SIZE = configTOTAL_HEAP_SIZE;
++void *pvPortMallocGeneric( size_t xWantedSize, size_t alignment);
 +
 +/* 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 )
+-void *pvPortMalloc( size_t xWantedSize )
-@@ -172,6 +175,12 @@
++void *pvPortMallocGeneric( size_t xWantedSize, size_t alignment)
+ {
+ void *pvReturn = NULL;
+ static unsigned char *pucAlignedHeap = NULL;
+-
++size_t mask = alignment-1;
+ 	/* Ensure that blocks are always aligned to the required number of bytes. */
+ 	#if portBYTE_ALIGNMENT != 1
+-		if( xWantedSize & portBYTE_ALIGNMENT_MASK )
++		if( xWantedSize & mask )
+ 		{
+-			/* Byte alignment required. */
+-			xWantedSize += ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) );
++		    			/* Byte alignment required. */
++			xWantedSize += ( alignment - ( xWantedSize & mask ) );
+ 		}
+ 	#endif
+ 
+@@ -120,7 +124,7 @@
+ 		if( pucAlignedHeap == NULL )
+ 		{
+ 			/* Ensure the heap starts on a correctly aligned boundary. */
+-			pucAlignedHeap = ( unsigned char * ) ( ( ( portPOINTER_SIZE_TYPE ) &ucHeap[ portBYTE_ALIGNMENT ] ) & ( ( portPOINTER_SIZE_TYPE ) ~portBYTE_ALIGNMENT_MASK ) );
++			pucAlignedHeap = ( unsigned char * ) ( ( ( portPOINTER_SIZE_TYPE ) &ucHeap[ alignment ] ) & ( ( portPOINTER_SIZE_TYPE ) ~ mask ) );
+ 		}
+ 
+ 		/* Check there is enough room left for the allocation. */
+@@ -147,6 +151,11 @@
+ 
+ 	return pvReturn;
+ }
++
++void *pvPortMalloc( size_t xWantedSize){
++    return pvPortMallocGeneric(xWantedSize, portBYTE_HEAP_ALIGNMENT);
++}
++
+ /*-----------------------------------------------------------*/
+ 
+ void vPortFree( void *pv )
+@@ -172,6 +181,12 @@
  {
  	return ( configADJUSTED_HEAP_SIZE - xNextFreeByte );
  }
@@ -90,3 +148,5 @@ xPortIncreaseHeapSize function.
 
 
 
+
+