Kernel changes:

+ Support tickless idle when configUSE_PREEMPTION is 0 (previously tickless idle was only supported when the pre-emptive scheduler was being used).
+ If a stack was statically allocated, then don't try freeing it if the TCB cannot be allocated.
+ Remove use of INCLUDE_xEventGroupsSetBitsFromISR() pre-processor macro, as it was not tested anyway.

Demo app changes:

+ Updated SAM4L Atmel Studio project to use Atmel Studio 7.

FreeRTOS/Source/event_groups.c

@@ -87,14 +87,6 @@ header files above, but not in this file, in order to generate the correct
 privileged Vs unprivileged linkage and placement. */
 #undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE /*lint !e961 !e750. */
 
-#if ( INCLUDE_xEventGroupSetBitFromISR == 1 ) && ( configUSE_TIMERS == 0 )
-	#error configUSE_TIMERS must be set to 1 to make the xEventGroupSetBitFromISR() function available.
-#endif
-
-#if ( INCLUDE_xEventGroupSetBitFromISR == 1 ) && ( INCLUDE_xTimerPendFunctionCall == 0 )
-	#error INCLUDE_xTimerPendFunctionCall must also be set to one to make the xEventGroupSetBitFromISR() function available.
-#endif
-
 /* The following bit fields convey control information in a task's event list
 item value.  It is important they don't clash with the
 taskEVENT_LIST_ITEM_VALUE_IN_USE definition. */

FreeRTOS/Source/include/FreeRTOS.h

@@ -247,10 +247,6 @@ extern "C" {
 	#define INCLUDE_xTaskResumeFromISR 1
 #endif
 
-#ifndef INCLUDE_xEventGroupSetBitFromISR
-	#define INCLUDE_xEventGroupSetBitFromISR 0
-#endif
-
 #ifndef INCLUDE_xTimerPendFunctionCall
 	#define INCLUDE_xTimerPendFunctionCall 0
 #endif
@@ -405,6 +401,10 @@ extern "C" {
 	#define traceMOVED_TASK_TO_READY_STATE( pxTCB )
 #endif
 
+#ifndef tracePOST_MOVED_TASK_TO_READY_STATE
+	#define tracePOST_MOVED_TASK_TO_READY_STATE( pxTCB )
+#endif
+
 #ifndef traceQUEUE_CREATE
 	#define traceQUEUE_CREATE( pxNewQueue )
 #endif
@@ -821,7 +821,7 @@ V8 if desired. */
 
 /* Set configUSE_TASK_FPU_SUPPORT to 0 to omit floating point support even
 if floating point hardware is otherwise supported by the FreeRTOS port in use.
-This constant is not supported by all FreeRTOS ports that include floating 
+This constant is not supported by all FreeRTOS ports that include floating
 point support. */
 #ifndef configUSE_TASK_FPU_SUPPORT
 	#define configUSE_TASK_FPU_SUPPORT 1

FreeRTOS/Source/include/event_groups.h

@@ -376,7 +376,7 @@ EventBits_t xEventGroupClearBits( EventGroupHandle_t xEventGroup, const EventBit
 		}
   }
    </pre>
- * \defgroup xEventGroupSetBitsFromISR xEventGroupSetBitsFromISR
+ * \defgroup xEventGroupClearBitsFromISR xEventGroupClearBitsFromISR
  * \ingroup EventGroup
  */
 #if( configUSE_TRACE_FACILITY == 1 )
@@ -470,7 +470,7 @@ EventBits_t xEventGroupSetBits( EventGroupHandle_t xEventGroup, const EventBits_
  * Setting bits in an event group is not a deterministic operation because there
  * are an unknown number of tasks that may be waiting for the bit or bits being
  * set.  FreeRTOS does not allow nondeterministic operations to be performed in
- * interrupts or from critical sections.  Therefore xEventGroupSetBitFromISR()
+ * interrupts or from critical sections.  Therefore xEventGroupSetBitsFromISR()
  * sends a message to the timer task to have the set operation performed in the
  * context of the timer task - where a scheduler lock is used in place of a
  * critical section.

FreeRTOS/Source/include/projdefs.h

@@ -107,6 +107,7 @@ typedef void (*TaskFunction_t)( void * );
 itself. */
 #define pdFREERTOS_ERRNO_NONE			0	/* No errors */
 #define	pdFREERTOS_ERRNO_ENOENT			2	/* No such file or directory */
+#define	pdFREERTOS_ERRNO_EINTR			4	/* Interrupted system call */
 #define	pdFREERTOS_ERRNO_EIO			5	/* I/O error */
 #define	pdFREERTOS_ERRNO_ENXIO			6	/* No such device or address */
 #define	pdFREERTOS_ERRNO_EBADF			9	/* Bad file number */

FreeRTOS/Source/portable/MSVC-MingW/portmacro.h

@@ -118,6 +118,7 @@ typedef unsigned long UBaseType_t;
 /* Simulated interrupts return pdFALSE if no context switch should be performed,
 or a non-zero number if a context switch should be performed. */
 #define portYIELD_FROM_ISR( x ) return x
+#define portEND_SWITCHING_ISR( x ) portYIELD_FROM_ISR( ( x ) )
 
 void vPortCloseRunningThread( void *pvTaskToDelete, volatile BaseType_t *pxPendYield );
 void vPortDeleteThread( void *pvThreadToDelete );

FreeRTOS/Source/portable/RVDS/ARM_CM3/portmacro.h

@@ -185,6 +185,8 @@ not necessary for to use this port.  They are defined so the common demo files
 /* portNOP() is not required by this port. */
 #define portNOP()
 
+#define portINLINE __inline
+
 #ifdef __cplusplus
 }
 #endif

FreeRTOS/Source/portable/RVDS/ARM_CM4F/portmacro.h

@@ -198,6 +198,8 @@ not necessary for to use this port.  They are defined so the common demo files
 /* portNOP() is not required by this port. */
 #define portNOP()
 
+#define portINLINE __inline
+
 #ifndef portFORCE_INLINE
 	#define portFORCE_INLINE __forceinline
 #endif

FreeRTOS/Source/portable/RVDS/ARM_CM7/r0p1/portmacro.h

@@ -202,6 +202,8 @@ not necessary for to use this port.  They are defined so the common demo files
 	#define portFORCE_INLINE __forceinline
 #endif
 
+#define portINLINE __inline
+
 /*-----------------------------------------------------------*/
 
 static portFORCE_INLINE void vPortSetBASEPRI( uint32_t ulBASEPRI )

FreeRTOS/Source/portable/readme.txt

@@ -1,19 +1,19 @@
 Each real time kernel port consists of three files that contain the core kernel
-components and are common to every port, and one or more files that are 
+components and are common to every port, and one or more files that are
 specific to a particular microcontroller and/or compiler.
 
 
-+ The FreeRTOS/Source/Portable/MemMang directory contains the three sample 
++ The FreeRTOS/Source/Portable/MemMang directory contains the three sample
 memory allocators as described on the http://www.FreeRTOS.org WEB site.
 
-+ The other directories each contain files specific to a particular 
++ The other directories each contain files specific to a particular
 microcontroller or compiler.
 
 
 
-For example, if you are interested in the GCC port for the ATMega323 
-microcontroller then the port specific files are contained in
-FreeRTOS/Source/Portable/GCC/ATMega323 directory.  If this is the only
-port you are interested in then all the other directories can be
+For example, if you are interested in the [compiler] port for the [architecture]
+microcontroller, then the port specific files are contained in
+FreeRTOS/Source/Portable/[compiler]/[architecture] directory.  If this is the
+only port you are interested in then all the other directories can be
 ignored.
 

FreeRTOS/Source/tasks.c

@@ -341,7 +341,7 @@ PRIVILEGED_DATA static volatile UBaseType_t uxSchedulerSuspended	= ( UBaseType_t
 	{																								\
 	UBaseType_t uxTopPriority;																		\
 																									\
-		/* Find the highest priority queue that contains ready tasks. */							\
+		/* Find the highest priority list that contains ready tasks. */								\
 		portGET_HIGHEST_PRIORITY( uxTopPriority, uxTopReadyPriority );								\
 		configASSERT( listCURRENT_LIST_LENGTH( &( pxReadyTasksLists[ uxTopPriority ] ) ) > 0 );		\
 		listGET_OWNER_OF_NEXT_ENTRY( pxCurrentTCB, &( pxReadyTasksLists[ uxTopPriority ] ) );		\
@@ -389,7 +389,8 @@ count overflows. */
 #define prvAddTaskToReadyList( pxTCB )																\
 	traceMOVED_TASK_TO_READY_STATE( pxTCB );														\
 	taskRECORD_READY_PRIORITY( ( pxTCB )->uxPriority );												\
-	vListInsertEnd( &( pxReadyTasksLists[ ( pxTCB )->uxPriority ] ), &( ( pxTCB )->xGenericListItem ) )
+	vListInsertEnd( &( pxReadyTasksLists[ ( pxTCB )->uxPriority ] ), &( ( pxTCB )->xGenericListItem ) ); \
+	tracePOST_MOVED_TASK_TO_READY_STATE( pxTCB )
 /*-----------------------------------------------------------*/
 
 /*
@@ -1645,6 +1646,34 @@ void vTaskSuspendAll( void )
 	static TickType_t prvGetExpectedIdleTime( void )
 	{
 	TickType_t xReturn;
+	UBaseType_t uxHigherPriorityReadyTasks = pdFALSE;
+
+		/* uxHigherPriorityReadyTasks takes care of the case where
+		configUSE_PREEMPTION is 0, so there may be tasks above the idle priority
+		task that are in the Ready state, even though the idle task is
+		running. */
+		#if( configUSE_PORT_OPTIMISED_TASK_SELECTION == 0 )
+		{
+			if( uxTopReadyPriority > tskIDLE_PRIORITY )
+			{
+				uxHigherPriorityReadyTasks = pdTRUE;
+			}
+		}
+		#else
+		{
+			const UBaseType_t uxLeastSignificantBit = ( UBaseType_t ) 0x01;
+
+			/* When port optimised task selection is used the uxTopReadyPriority
+			variable is used as a bit map.  If bits other than the least
+			significant bit are set then there are tasks that have a priority
+			above the idle priority that are in the Ready state.  This takes
+			care of the case where the co-operative scheduler is in use. */
+			if( uxTopReadyPriority > uxLeastSignificantBit )
+			{
+				uxHigherPriorityReadyTasks = pdTRUE;
+			}
+		}
+		#endif
 
 		if( pxCurrentTCB->uxPriority > tskIDLE_PRIORITY )
 		{
@@ -1657,6 +1686,13 @@ void vTaskSuspendAll( void )
 			processed. */
 			xReturn = 0;
 		}
+		else if( uxHigherPriorityReadyTasks != pdFALSE )
+		{
+			/* There are tasks in the Ready state that have a priority above the
+			idle priority.  This path can only be reached if
+			configUSE_PREEMPTION is 0. */
+			xReturn = 0;
+		}
 		else
 		{
 			xReturn = xNextTaskUnblockTime - xTickCount;
@@ -2222,9 +2258,9 @@ void vTaskSwitchContext( void )
 				#endif
 
 				/* Add the amount of time the task has been running to the
-				accumulated	time so far.  The time the task started running was
+				accumulated time so far.  The time the task started running was
 				stored in ulTaskSwitchedInTime.  Note that there is no overflow
-				protection here	so count values are only valid until the timer
+				protection here so count values are only valid until the timer
 				overflows.  The guard against negative values is to protect
 				against suspect run time stat counter implementations - which
 				are provided by the application, not the kernel. */
@@ -3148,7 +3184,10 @@ TCB_t *pxNewTCB;
 			{
 				/* The stack cannot be used as the TCB was not created.  Free it
 				again. */
-				vPortFree( pxStack );
+				if( puxStackBuffer == NULL )
+				{
+					vPortFree( pxStack );
+				}
 			}
 		}
 		else