Corrected SysTick_Handler and osKernelGetSysTimerCount to cope with tickless idle implementation (#60)

Author: VladimirUmek

ARM.CMSIS-FreeRTOS.pdsc

@@ -16,6 +16,7 @@
       - Corrected osEventFlagsSet return value when called from ISR
       - Corrected osEventFlagsWait to return osFlagsErrorParameter when called from ISR with non-zero timeout
       - Corrected osTimerStart to return osErrorParameter when ticks argument equals zero
+      - Corrected SysTick_Handler and osKernelGetSysTimerCount to cope with tickless idle implementation
       - Re-enable interrupts after mutex create in C lib stream protection initialization
     </release>
     <release version="10.4.6" date="2021-11-16">

CMSIS/RTOS2/FreeRTOS/Config/ARMCM/FreeRTOSConfig.h

@@ -88,6 +88,12 @@
 //  <i> Default: 1
 #define configUSE_TIME_SLICING                  1
 
+//  <q>Use tickless idle
+//  <i> Enable low power tickless mode to stop the periodic tick interrupt during idle periods or
+//  <i> disable it to keep the tick interrupt running at all times.
+//  <i> Default: 0
+#define configUSE_TICKLESS_IDLE                 0
+
 //  <q>Idle should yield
 //  <i> Control Yield behaviour of the idle task.
 //  <i> Default: 1

CMSIS/RTOS2/FreeRTOS/Examples/Blinky/RTE/RTOS/FreeRTOSConfig.h

@@ -88,6 +88,12 @@
 //  <i> Default: 1
 #define configUSE_TIME_SLICING                  1
 
+//  <q>Use tickless idle
+//  <i> Enable low power tickless mode to stop the periodic tick interrupt during idle periods or
+//  <i> disable it to keep the tick interrupt running at all times.
+//  <i> Default: 0
+#define configUSE_TICKLESS_IDLE                 0
+
 //  <q>Idle should yield
 //  <i> Control Yield behaviour of the idle task.
 //  <i> Default: 1

CMSIS/RTOS2/FreeRTOS/Examples/Blinky_IAR/Blinky/RTE/RTOS/FreeRTOSConfig.h

@@ -1,5 +1,5 @@
 /* --------------------------------------------------------------------------
- * Copyright (c) 2013-2021 Arm Limited. All rights reserved.
+ * Copyright (c) 2013-2022 Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: Apache-2.0
  *
@@ -17,7 +17,7 @@
  *
  * --------------------------------------------------------------------------
  *
- * $Revision:   V10.3.0
+ * $Revision:   V10.4.0
  *
  * Project:     CMSIS-FreeRTOS
  * Title:       FreeRTOS configuration definitions
@@ -88,6 +88,12 @@
 //  <i> Default: 1
 #define configUSE_TIME_SLICING                  1
 
+//  <q>Use tickless idle
+//  <i> Enable low power tickless mode to stop the periodic tick interrupt during idle periods or
+//  <i> disable it to keep the tick interrupt running at all times.
+//  <i> Default: 0
+#define configUSE_TICKLESS_IDLE                 0
+
 //  <q>Idle should yield
 //  <i> Control Yield behaviour of the idle task.
 //  <i> Default: 1
@@ -192,6 +198,12 @@
 //  <i> Default: 1
 #define configENABLE_FPU                      1
 
+//  <q>Use M-Profile Vector Extension
+//  <i> Using M-Profile Vector Extension (MVE) affects context handling.
+//  <i> Enable MVE when application uses signal processing and ML algorithms.
+//  <i> Default: 0
+#define configENABLE_MVE                      0
+
 //  <q>Use Memory Protection Unit
 //  <i> Using Memory Protection Unit (MPU) requires detailed memory map definition.
 //  <i> This setting is only releavant for MPU enabled ports.

CMSIS/RTOS2/FreeRTOS/Examples/TrustZone/NonSecure/RTE/RTOS/FreeRTOSConfig.h

@@ -88,6 +88,12 @@
 //  <i> Default: 1
 #define configUSE_TIME_SLICING                  1
 
+//  <q>Use tickless idle
+//  <i> Enable low power tickless mode to stop the periodic tick interrupt during idle periods or
+//  <i> disable it to keep the tick interrupt running at all times.
+//  <i> Default: 0
+#define configUSE_TICKLESS_IDLE                 0
+
 //  <q>Idle should yield
 //  <i> Control Yield behaviour of the idle task.
 //  <i> Default: 1

CMSIS/RTOS2/FreeRTOS/Source/cmsis_os2.c

@@ -154,8 +154,10 @@ extern void xPortSysTickHandler (void);
   SysTick handler implementation that also clears overflow flag.
 */
 void SysTick_Handler (void) {
+#if (configUSE_TICKLESS_IDLE == 0)
   /* Clear overflow flag */
   SysTick->CTRL;
+#endif
 
   if (xTaskGetSchedulerState() != taskSCHEDULER_NOT_STARTED) {
     /* Call tick handler */
@@ -474,17 +476,35 @@ uint32_t osKernelGetSysTimerCount (void) {
   uint32_t irqmask = IS_IRQ_MASKED();
   TickType_t ticks;
   uint32_t val;
+#if (configUSE_TICKLESS_IDLE != 0)
+  uint32_t val0;
+
+  /* Low Power Tickless Idle controls timer overflow flag and therefore      */
+  /* OS_Tick_GetOverflow may be non-functional. As a workaround a reference  */
+  /* time is measured here before disabling interrupts. Timer value overflow */
+  /* is then checked by comparing reference against latest time measurement. */
+  /* Timer count value returned by this method is less accurate but if an    */
+  /* overflow is missed, an invalid timer count would be returned.           */
+  val0 = OS_Tick_GetCount();
+#endif
 
   __disable_irq();
 
   ticks = xTaskGetTickCount();
   val   = OS_Tick_GetCount();
 
   /* Update tick count and timer value when timer overflows */
+#if (configUSE_TICKLESS_IDLE != 0)
+  if (val < val0) {
+    ticks++;
+  }
+#else
   if (OS_Tick_GetOverflow() != 0U) {
     val = OS_Tick_GetCount();
     ticks++;
   }
+#endif
+
   val += ticks * OS_Tick_GetInterval();
 
   if (irqmask == 0U) {

DoxyGen/General/src/cmsis_freertos.txt

@@ -65,6 +65,7 @@ File/Directory             |Content
           <li>Corrected osEventFlagsSet return value when called from ISR</li>
           <li>Corrected osEventFlagsWait to return osFlagsErrorParameter when called from ISR with non-zero timeout</li>
           <li>Corrected osTimerStart to return osErrorParameter when ticks argument equals zero</li>
+          <li>Corrected SysTick_Handler and osKernelGetSysTimerCount to cope with tickless idle implementation</li>
           <li>Re-enable interrupts after mutex create in C lib stream protection initialization (#55)</li>
         </ul>
       </td>