xtensa port: count ticks separately

If xTaskIncrementTick is called while the scheduler is suspended then OS
tick counter update is delayed. vPortSuppressTicksAndSleep is always
called with suspended scheduler, so timer deadline in ccompare SR may
not correspong to the current OS tick. Count ticks separately in the
port and use that counter to calculate future timer deadlines.

Signed-off-by: Max Filippov <[email protected]>

portable/XCC/Xtensa/port.c

@@ -90,6 +90,8 @@ extern void _xt_task_start( void );
 static uint32_t xt_tick_cycles;
 TickType_t xMaxSuppressedTicks;
 
+static uint32_t xt_tick_count;
+
 #if ( configUSE_TICKLESS_IDLE != 0 )
 // Flag to indicate tick handling should be skipped.
 static volatile uint32_t xt_skip_tick;
@@ -114,6 +116,7 @@ static void xt_tick_handler( void )
     if ( xt_skip_tick )
     {
         vTaskStepTick( xt_skip_tick );
+        xt_tick_count += xt_skip_tick;
         xt_skip_tick = 0;
     }
 #endif
@@ -135,6 +138,7 @@ static void xt_tick_handler( void )
         interruptMask = portSET_INTERRUPT_MASK_FROM_ISR();
         {
             ret = xTaskIncrementTick();
+            ++xt_tick_count;
         }
         portCLEAR_INTERRUPT_MASK_FROM_ISR( interruptMask );
 
@@ -165,6 +169,7 @@ static void xt_tick_timer_init( void )
     xMaxSuppressedTicks = 0xFFFFFFFFU / xt_tick_cycles;
     xt_set_interrupt_handler( XT_TIMER_INTNUM, (xt_handler) xt_tick_handler, 0 );
     xt_set_ccompare( XT_TIMER_INDEX, xthal_get_ccount() + xt_tick_cycles );
+    xt_tick_count = xTaskGetTickCount();
     xt_interrupt_enable( XT_TIMER_INTNUM );
 }
 
@@ -329,7 +334,7 @@ void vPortSuppressTicksAndSleep( TickType_t target, TickType_t xExpectedIdleTime
         uint32_t skip_tick;
         uint32_t now;
 
-        xExpectedIdleTime = target - xTaskGetTickCountFromISR ();
+        xExpectedIdleTime = target - xt_tick_count;
         // Compute number of cycles to sleep for, capped by max limit.
         // we use one less than the number of ticks because we are already
         // partway through the current tick. This is adjusted later below.
@@ -377,6 +382,7 @@ void vPortSuppressTicksAndSleep( TickType_t target, TickType_t xExpectedIdleTime
                 do
                 {
                     vTaskStepTick( ticks );
+                    xt_tick_count += ticks;
                     xt_set_ccompare( XT_TIMER_INDEX, ccompare );
                     diff = xt_get_ccount() - ccompare;
                     ccompare += xt_tick_cycles;
@@ -387,6 +393,7 @@ void vPortSuppressTicksAndSleep( TickType_t target, TickType_t xExpectedIdleTime
             else
             {
                 vTaskStepTick( skip_tick );
+                xt_tick_count += skip_tick;
             }
 
             xt_skip_tick = 0;