mirror of
https://github.com/FreeRTOS/FreeRTOS-Kernel.git
synced 2025-04-20 05:21:59 -04:00
Cortex M0 GCC/IAR/Keil ports -- tickless support.
The default portMISSED_COUNTS_FACTOR is set to 45 cycles. User could override this value, if a more accurate count is available.
This commit is contained in:
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3cde02a046
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@ -34,15 +34,16 @@
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#include "task.h"
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#include "task.h"
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/* Constants required to manipulate the NVIC. */
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/* Constants required to manipulate the NVIC. */
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#define portNVIC_SYSTICK_CTRL ( ( volatile uint32_t * ) 0xe000e010 )
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#define portNVIC_SYSTICK_CTRL_REG ( * ( ( volatile uint32_t * ) 0xe000e010 ) )
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#define portNVIC_SYSTICK_LOAD ( ( volatile uint32_t * ) 0xe000e014 )
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#define portNVIC_SYSTICK_LOAD_REG ( * ( ( volatile uint32_t * ) 0xe000e014 ) )
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#define portNVIC_SYSTICK_CURRENT_VALUE ( ( volatile uint32_t * ) 0xe000e018 )
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#define portNVIC_SYSTICK_CURRENT_VALUE_REG ( * ( ( volatile uint32_t * ) 0xe000e018 ) )
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#define portNVIC_INT_CTRL ( ( volatile uint32_t *) 0xe000ed04 )
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#define portNVIC_INT_CTRL_REG ( * ( ( volatile uint32_t * ) 0xe000ed04 ) )
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#define portNVIC_SYSPRI2 ( ( volatile uint32_t *) 0xe000ed20 )
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#define portNVIC_SYSPRI2_REG ( * ( ( volatile uint32_t * ) 0xe000ed20 ) )
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#define portNVIC_SYSTICK_CLK 0x00000004
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#define portNVIC_SYSTICK_CLK_BIT ( 1UL << 2UL )
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#define portNVIC_SYSTICK_INT 0x00000002
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#define portNVIC_SYSTICK_INT_BIT ( 1UL << 1UL )
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#define portNVIC_SYSTICK_ENABLE 0x00000001
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#define portNVIC_SYSTICK_ENABLE_BIT ( 1UL << 0UL )
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#define portNVIC_PENDSVSET 0x10000000
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#define portNVIC_SYSTICK_COUNT_FLAG_BIT ( 1UL << 16UL )
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#define portNVIC_PENDSVSET_BIT ( 1UL << 28UL )
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#define portMIN_INTERRUPT_PRIORITY ( 255UL )
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#define portMIN_INTERRUPT_PRIORITY ( 255UL )
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#define portNVIC_PENDSV_PRI ( portMIN_INTERRUPT_PRIORITY << 16UL )
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#define portNVIC_PENDSV_PRI ( portMIN_INTERRUPT_PRIORITY << 16UL )
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#define portNVIC_SYSTICK_PRI ( portMIN_INTERRUPT_PRIORITY << 24UL )
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#define portNVIC_SYSTICK_PRI ( portMIN_INTERRUPT_PRIORITY << 24UL )
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@ -50,6 +51,16 @@
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/* Constants required to set up the initial stack. */
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/* Constants required to set up the initial stack. */
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#define portINITIAL_XPSR ( 0x01000000 )
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#define portINITIAL_XPSR ( 0x01000000 )
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/* The systick is a 24-bit counter. */
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#define portMAX_24_BIT_NUMBER ( 0xffffffUL )
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/* A fiddle factor to estimate the number of SysTick counts that would have
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occurred while the SysTick counter is stopped during tickless idle
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calculations. */
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#ifndef portMISSED_COUNTS_FACTOR
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#define portMISSED_COUNTS_FACTOR ( 45UL )
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#endif
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/* Let the user override the pre-loading of the initial LR with the address of
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/* Let the user override the pre-loading of the initial LR with the address of
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prvTaskExitError() in case it messes up unwinding of the stack in the
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prvTaskExitError() in case it messes up unwinding of the stack in the
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debugger. */
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debugger. */
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@ -89,6 +100,31 @@ static UBaseType_t uxCriticalNesting = 0xaaaaaaaa;
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/*-----------------------------------------------------------*/
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/*-----------------------------------------------------------*/
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/*
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* The number of SysTick increments that make up one tick period.
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*/
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#if( configUSE_TICKLESS_IDLE == 1 )
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static uint32_t ulTimerCountsForOneTick = 0;
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#endif /* configUSE_TICKLESS_IDLE */
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/*
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* The maximum number of tick periods that can be suppressed is limited by the
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* 24 bit resolution of the SysTick timer.
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*/
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#if( configUSE_TICKLESS_IDLE == 1 )
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static uint32_t xMaximumPossibleSuppressedTicks = 0;
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#endif /* configUSE_TICKLESS_IDLE */
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/*
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* Compensate for the CPU cycles that pass while the SysTick is stopped (low
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* power functionality only.
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*/
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#if( configUSE_TICKLESS_IDLE == 1 )
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static uint32_t ulStoppedTimerCompensation = 0;
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#endif /* configUSE_TICKLESS_IDLE */
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/*-----------------------------------------------------------*/
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/*
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/*
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* See header file for description.
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* See header file for description.
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*/
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*/
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@ -176,8 +212,8 @@ void vPortStartFirstTask( void )
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BaseType_t xPortStartScheduler( void )
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BaseType_t xPortStartScheduler( void )
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{
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{
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/* Make PendSV, CallSV and SysTick the same priority as the kernel. */
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/* Make PendSV, CallSV and SysTick the same priority as the kernel. */
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*(portNVIC_SYSPRI2) |= portNVIC_PENDSV_PRI;
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portNVIC_SYSPRI2_REG |= portNVIC_PENDSV_PRI;
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*(portNVIC_SYSPRI2) |= portNVIC_SYSTICK_PRI;
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portNVIC_SYSPRI2_REG |= portNVIC_SYSTICK_PRI;
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/* Start the timer that generates the tick ISR. Interrupts are disabled
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/* Start the timer that generates the tick ISR. Interrupts are disabled
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here already. */
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here already. */
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@ -214,7 +250,7 @@ void vPortEndScheduler( void )
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void vPortYield( void )
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void vPortYield( void )
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{
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{
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/* Set a PendSV to request a context switch. */
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/* Set a PendSV to request a context switch. */
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*( portNVIC_INT_CTRL ) = portNVIC_PENDSVSET;
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portNVIC_INT_CTRL_REG = portNVIC_PENDSVSET_BIT;
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/* Barriers are normally not required but do ensure the code is completely
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/* Barriers are normally not required but do ensure the code is completely
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within the specified behaviour for the architecture. */
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within the specified behaviour for the architecture. */
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@ -323,7 +359,7 @@ uint32_t ulPreviousMask;
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if( xTaskIncrementTick() != pdFALSE )
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if( xTaskIncrementTick() != pdFALSE )
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{
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{
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/* Pend a context switch. */
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/* Pend a context switch. */
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*(portNVIC_INT_CTRL) = portNVIC_PENDSVSET;
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portNVIC_INT_CTRL_REG = portNVIC_PENDSVSET_BIT;
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}
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}
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}
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}
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portCLEAR_INTERRUPT_MASK_FROM_ISR( ulPreviousMask );
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portCLEAR_INTERRUPT_MASK_FROM_ISR( ulPreviousMask );
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@ -336,13 +372,187 @@ uint32_t ulPreviousMask;
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*/
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*/
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void prvSetupTimerInterrupt( void )
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void prvSetupTimerInterrupt( void )
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{
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{
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/* Calculate the constants required to configure the tick interrupt. */
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#if( configUSE_TICKLESS_IDLE == 1 )
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{
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ulTimerCountsForOneTick = ( configCPU_CLOCK_HZ / configTICK_RATE_HZ );
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xMaximumPossibleSuppressedTicks = portMAX_24_BIT_NUMBER / ulTimerCountsForOneTick;
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ulStoppedTimerCompensation = portMISSED_COUNTS_FACTOR;
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}
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#endif /* configUSE_TICKLESS_IDLE */
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/* Stop and reset the SysTick. */
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/* Stop and reset the SysTick. */
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*(portNVIC_SYSTICK_CTRL) = 0UL;
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portNVIC_SYSTICK_CTRL_REG = 0UL;
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*(portNVIC_SYSTICK_CURRENT_VALUE) = 0UL;
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portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;
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/* Configure SysTick to interrupt at the requested rate. */
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/* Configure SysTick to interrupt at the requested rate. */
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*(portNVIC_SYSTICK_LOAD) = ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;
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portNVIC_SYSTICK_LOAD_REG = ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;
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*(portNVIC_SYSTICK_CTRL) = portNVIC_SYSTICK_CLK | portNVIC_SYSTICK_INT | portNVIC_SYSTICK_ENABLE;
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portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
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}
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}
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/*-----------------------------------------------------------*/
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/*-----------------------------------------------------------*/
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#if( configUSE_TICKLESS_IDLE == 1 )
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__attribute__((weak)) void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime )
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{
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uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements;
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TickType_t xModifiableIdleTime;
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/* Make sure the SysTick reload value does not overflow the counter. */
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if( xExpectedIdleTime > xMaximumPossibleSuppressedTicks )
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{
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xExpectedIdleTime = xMaximumPossibleSuppressedTicks;
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}
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/* Stop the SysTick momentarily. The time the SysTick is stopped for
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is accounted for as best it can be, but using the tickless mode will
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inevitably result in some tiny drift of the time maintained by the
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kernel with respect to calendar time. */
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portNVIC_SYSTICK_CTRL_REG &= ~portNVIC_SYSTICK_ENABLE_BIT;
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/* Calculate the reload value required to wait xExpectedIdleTime
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tick periods. -1 is used because this code will execute part way
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through one of the tick periods. */
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ulReloadValue = portNVIC_SYSTICK_CURRENT_VALUE_REG + ( ulTimerCountsForOneTick * ( xExpectedIdleTime - 1UL ) );
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if( ulReloadValue > ulStoppedTimerCompensation )
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{
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ulReloadValue -= ulStoppedTimerCompensation;
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}
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/* Enter a critical section but don't use the taskENTER_CRITICAL()
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method as that will mask interrupts that should exit sleep mode. */
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__asm volatile( "cpsid i" ::: "memory" );
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__asm volatile( "dsb" );
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__asm volatile( "isb" );
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/* If a context switch is pending or a task is waiting for the scheduler
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to be unsuspended then abandon the low power entry. */
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if( eTaskConfirmSleepModeStatus() == eAbortSleep )
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{
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/* Restart from whatever is left in the count register to complete
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this tick period. */
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portNVIC_SYSTICK_LOAD_REG = portNVIC_SYSTICK_CURRENT_VALUE_REG;
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/* Restart SysTick. */
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portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT;
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/* Reset the reload register to the value required for normal tick
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periods. */
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portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL;
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/* Re-enable interrupts - see comments above the cpsid instruction()
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above. */
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__asm volatile( "cpsie i" ::: "memory" );
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}
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else
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{
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/* Set the new reload value. */
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portNVIC_SYSTICK_LOAD_REG = ulReloadValue;
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/* Clear the SysTick count flag and set the count value back to
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zero. */
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portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;
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/* Restart SysTick. */
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portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT;
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/* Sleep until something happens. configPRE_SLEEP_PROCESSING() can
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set its parameter to 0 to indicate that its implementation contains
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its own wait for interrupt or wait for event instruction, and so wfi
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should not be executed again. However, the original expected idle
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time variable must remain unmodified, so a copy is taken. */
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xModifiableIdleTime = xExpectedIdleTime;
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configPRE_SLEEP_PROCESSING( xModifiableIdleTime );
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if( xModifiableIdleTime > 0 )
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{
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__asm volatile( "dsb" ::: "memory" );
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__asm volatile( "wfi" );
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__asm volatile( "isb" );
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}
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configPOST_SLEEP_PROCESSING( xExpectedIdleTime );
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/* Re-enable interrupts to allow the interrupt that brought the MCU
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out of sleep mode to execute immediately. see comments above
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__disable_interrupt() call above. */
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__asm volatile( "cpsie i" ::: "memory" );
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__asm volatile( "dsb" );
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__asm volatile( "isb" );
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/* Disable interrupts again because the clock is about to be stopped
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and interrupts that execute while the clock is stopped will increase
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any slippage between the time maintained by the RTOS and calendar
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time. */
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__asm volatile( "cpsid i" ::: "memory" );
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__asm volatile( "dsb" );
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__asm volatile( "isb" );
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/* Disable the SysTick clock without reading the
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portNVIC_SYSTICK_CTRL_REG register to ensure the
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portNVIC_SYSTICK_COUNT_FLAG_BIT is not cleared if it is set. Again,
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the time the SysTick is stopped for is accounted for as best it can
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be, but using the tickless mode will inevitably result in some tiny
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drift of the time maintained by the kernel with respect to calendar
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time*/
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portNVIC_SYSTICK_CTRL_REG = ( portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT );
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/* Determine if the SysTick clock has already counted to zero and
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been set back to the current reload value (the reload back being
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correct for the entire expected idle time) or if the SysTick is yet
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to count to zero (in which case an interrupt other than the SysTick
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must have brought the system out of sleep mode). */
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if( ( portNVIC_SYSTICK_CTRL_REG & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 )
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{
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uint32_t ulCalculatedLoadValue;
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/* The tick interrupt is already pending, and the SysTick count
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reloaded with ulReloadValue. Reset the
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portNVIC_SYSTICK_LOAD_REG with whatever remains of this tick
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period. */
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ulCalculatedLoadValue = ( ulTimerCountsForOneTick - 1UL ) - ( ulReloadValue - portNVIC_SYSTICK_CURRENT_VALUE_REG );
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/* Don't allow a tiny value, or values that have somehow
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underflowed because the post sleep hook did something
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that took too long. */
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if( ( ulCalculatedLoadValue < ulStoppedTimerCompensation ) || ( ulCalculatedLoadValue > ulTimerCountsForOneTick ) )
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{
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ulCalculatedLoadValue = ( ulTimerCountsForOneTick - 1UL );
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}
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portNVIC_SYSTICK_LOAD_REG = ulCalculatedLoadValue;
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/* As the pending tick will be processed as soon as this
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function exits, the tick value maintained by the tick is stepped
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forward by one less than the time spent waiting. */
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ulCompleteTickPeriods = xExpectedIdleTime - 1UL;
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}
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else
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{
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/* Something other than the tick interrupt ended the sleep.
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Work out how long the sleep lasted rounded to complete tick
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periods (not the ulReload value which accounted for part
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ticks). */
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ulCompletedSysTickDecrements = ( xExpectedIdleTime * ulTimerCountsForOneTick ) - portNVIC_SYSTICK_CURRENT_VALUE_REG;
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/* How many complete tick periods passed while the processor
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was waiting? */
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ulCompleteTickPeriods = ulCompletedSysTickDecrements / ulTimerCountsForOneTick;
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/* The reload value is set to whatever fraction of a single tick
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period remains. */
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portNVIC_SYSTICK_LOAD_REG = ( ( ulCompleteTickPeriods + 1UL ) * ulTimerCountsForOneTick ) - ulCompletedSysTickDecrements;
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}
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/* Restart SysTick so it runs from portNVIC_SYSTICK_LOAD_REG
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again, then set portNVIC_SYSTICK_LOAD_REG back to its standard
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value. */
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portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;
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portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT;
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vTaskStepTick( ulCompleteTickPeriods );
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portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL;
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/* Exit with interrpts enabled. */
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__asm volatile( "cpsie i" ::: "memory" );
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}
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}
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#endif /* configUSE_TICKLESS_IDLE */
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@ -101,6 +101,13 @@ extern void vClearInterruptMaskFromISR( uint32_t ulMask ) __attribute__((naked)
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/*-----------------------------------------------------------*/
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/*-----------------------------------------------------------*/
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/* Tickless idle/low power functionality. */
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#ifndef portSUPPRESS_TICKS_AND_SLEEP
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extern void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime );
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#define portSUPPRESS_TICKS_AND_SLEEP( xExpectedIdleTime ) vPortSuppressTicksAndSleep( xExpectedIdleTime )
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#endif
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/*-----------------------------------------------------------*/
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/* Task function macros as described on the FreeRTOS.org WEB site. */
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/* Task function macros as described on the FreeRTOS.org WEB site. */
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#define portTASK_FUNCTION_PROTO( vFunction, pvParameters ) void vFunction( void *pvParameters )
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#define portTASK_FUNCTION_PROTO( vFunction, pvParameters ) void vFunction( void *pvParameters )
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#define portTASK_FUNCTION( vFunction, pvParameters ) void vFunction( void *pvParameters )
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#define portTASK_FUNCTION( vFunction, pvParameters ) void vFunction( void *pvParameters )
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@ -37,13 +37,15 @@
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#include "task.h"
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#include "task.h"
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/* Constants required to manipulate the NVIC. */
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/* Constants required to manipulate the NVIC. */
|
||||||
#define portNVIC_SYSTICK_CTRL ( ( volatile uint32_t * ) 0xe000e010 )
|
#define portNVIC_SYSTICK_CTRL_REG ( * ( ( volatile uint32_t * ) 0xe000e010 ) )
|
||||||
#define portNVIC_SYSTICK_LOAD ( ( volatile uint32_t * ) 0xe000e014 )
|
#define portNVIC_SYSTICK_LOAD_REG ( * ( ( volatile uint32_t * ) 0xe000e014 ) )
|
||||||
#define portNVIC_SYSTICK_CURRENT_VALUE ( ( volatile uint32_t * ) 0xe000e018 )
|
#define portNVIC_SYSTICK_CURRENT_VALUE_REG ( * ( ( volatile uint32_t * ) 0xe000e018 ) )
|
||||||
#define portNVIC_SYSPRI2 ( ( volatile uint32_t *) 0xe000ed20 )
|
#define portNVIC_INT_CTRL_REG ( * ( ( volatile uint32_t * ) 0xe000ed04 ) )
|
||||||
#define portNVIC_SYSTICK_CLK 0x00000004
|
#define portNVIC_SYSPRI2_REG ( * ( ( volatile uint32_t *) 0xe000ed20 ) )
|
||||||
#define portNVIC_SYSTICK_INT 0x00000002
|
#define portNVIC_SYSTICK_CLK_BIT ( 1UL << 2UL )
|
||||||
#define portNVIC_SYSTICK_ENABLE 0x00000001
|
#define portNVIC_SYSTICK_INT_BIT ( 1UL << 1UL )
|
||||||
|
#define portNVIC_SYSTICK_ENABLE_BIT ( 1UL << 0UL )
|
||||||
|
#define portNVIC_SYSTICK_COUNT_FLAG_BIT ( 1UL << 16UL )
|
||||||
#define portMIN_INTERRUPT_PRIORITY ( 255UL )
|
#define portMIN_INTERRUPT_PRIORITY ( 255UL )
|
||||||
#define portNVIC_PENDSV_PRI ( portMIN_INTERRUPT_PRIORITY << 16UL )
|
#define portNVIC_PENDSV_PRI ( portMIN_INTERRUPT_PRIORITY << 16UL )
|
||||||
#define portNVIC_SYSTICK_PRI ( portMIN_INTERRUPT_PRIORITY << 24UL )
|
#define portNVIC_SYSTICK_PRI ( portMIN_INTERRUPT_PRIORITY << 24UL )
|
||||||
|
@ -62,6 +64,33 @@ FreeRTOS.org versions prior to V4.3.0 did not include this definition. */
|
||||||
variable. */
|
variable. */
|
||||||
static UBaseType_t uxCriticalNesting = 0xaaaaaaaa;
|
static UBaseType_t uxCriticalNesting = 0xaaaaaaaa;
|
||||||
|
|
||||||
|
/* The systick is a 24-bit counter. */
|
||||||
|
#define portMAX_24_BIT_NUMBER ( 0xffffffUL )
|
||||||
|
|
||||||
|
/* A fiddle factor to estimate the number of SysTick counts that would have
|
||||||
|
occurred while the SysTick counter is stopped during tickless idle
|
||||||
|
calculations. */
|
||||||
|
#ifndef portMISSED_COUNTS_FACTOR
|
||||||
|
#define portMISSED_COUNTS_FACTOR ( 45UL )
|
||||||
|
#endif
|
||||||
|
|
||||||
|
/* The number of SysTick increments that make up one tick period. */
|
||||||
|
#if( configUSE_TICKLESS_IDLE == 1 )
|
||||||
|
static uint32_t ulTimerCountsForOneTick = 0;
|
||||||
|
#endif /* configUSE_TICKLESS_IDLE */
|
||||||
|
|
||||||
|
/* The maximum number of tick periods that can be suppressed is limited by the
|
||||||
|
24 bit resolution of the SysTick timer. */
|
||||||
|
#if( configUSE_TICKLESS_IDLE == 1 )
|
||||||
|
static uint32_t xMaximumPossibleSuppressedTicks = 0;
|
||||||
|
#endif /* configUSE_TICKLESS_IDLE */
|
||||||
|
|
||||||
|
/* Compensate for the CPU cycles that pass while the SysTick is stopped (low
|
||||||
|
power functionality only. */
|
||||||
|
#if( configUSE_TICKLESS_IDLE == 1 )
|
||||||
|
static uint32_t ulStoppedTimerCompensation = 0;
|
||||||
|
#endif /* configUSE_TICKLESS_IDLE */
|
||||||
|
|
||||||
/*
|
/*
|
||||||
* Setup the timer to generate the tick interrupts.
|
* Setup the timer to generate the tick interrupts.
|
||||||
*/
|
*/
|
||||||
|
@ -125,8 +154,8 @@ static void prvTaskExitError( void )
|
||||||
BaseType_t xPortStartScheduler( void )
|
BaseType_t xPortStartScheduler( void )
|
||||||
{
|
{
|
||||||
/* Make PendSV and SysTick the lowest priority interrupts. */
|
/* Make PendSV and SysTick the lowest priority interrupts. */
|
||||||
*(portNVIC_SYSPRI2) |= portNVIC_PENDSV_PRI;
|
portNVIC_SYSPRI2_REG |= portNVIC_PENDSV_PRI;
|
||||||
*(portNVIC_SYSPRI2) |= portNVIC_SYSTICK_PRI;
|
portNVIC_SYSPRI2_REG |= portNVIC_SYSTICK_PRI;
|
||||||
|
|
||||||
/* Start the timer that generates the tick ISR. Interrupts are disabled
|
/* Start the timer that generates the tick ISR. Interrupts are disabled
|
||||||
here already. */
|
here already. */
|
||||||
|
@ -154,7 +183,7 @@ void vPortEndScheduler( void )
|
||||||
void vPortYield( void )
|
void vPortYield( void )
|
||||||
{
|
{
|
||||||
/* Set a PendSV to request a context switch. */
|
/* Set a PendSV to request a context switch. */
|
||||||
*(portNVIC_INT_CTRL) = portNVIC_PENDSVSET;
|
portNVIC_INT_CTRL_REG = portNVIC_PENDSVSET;
|
||||||
|
|
||||||
/* Barriers are normally not required but do ensure the code is completely
|
/* Barriers are normally not required but do ensure the code is completely
|
||||||
within the specified behaviour for the architecture. */
|
within the specified behaviour for the architecture. */
|
||||||
|
@ -193,7 +222,7 @@ uint32_t ulPreviousMask;
|
||||||
if( xTaskIncrementTick() != pdFALSE )
|
if( xTaskIncrementTick() != pdFALSE )
|
||||||
{
|
{
|
||||||
/* Pend a context switch. */
|
/* Pend a context switch. */
|
||||||
*(portNVIC_INT_CTRL) = portNVIC_PENDSVSET;
|
portNVIC_INT_CTRL_REG = portNVIC_PENDSVSET;
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
portCLEAR_INTERRUPT_MASK_FROM_ISR( ulPreviousMask );
|
portCLEAR_INTERRUPT_MASK_FROM_ISR( ulPreviousMask );
|
||||||
|
@ -206,13 +235,187 @@ uint32_t ulPreviousMask;
|
||||||
*/
|
*/
|
||||||
static void prvSetupTimerInterrupt( void )
|
static void prvSetupTimerInterrupt( void )
|
||||||
{
|
{
|
||||||
|
/* Calculate the constants required to configure the tick interrupt. */
|
||||||
|
#if( configUSE_TICKLESS_IDLE == 1 )
|
||||||
|
{
|
||||||
|
ulTimerCountsForOneTick = ( configCPU_CLOCK_HZ / configTICK_RATE_HZ );
|
||||||
|
xMaximumPossibleSuppressedTicks = portMAX_24_BIT_NUMBER / ulTimerCountsForOneTick;
|
||||||
|
ulStoppedTimerCompensation = portMISSED_COUNTS_FACTOR;
|
||||||
|
}
|
||||||
|
#endif /* configUSE_TICKLESS_IDLE */
|
||||||
|
|
||||||
/* Stop and reset the SysTick. */
|
/* Stop and reset the SysTick. */
|
||||||
*(portNVIC_SYSTICK_CTRL) = 0UL;
|
portNVIC_SYSTICK_CTRL_REG = 0UL;
|
||||||
*(portNVIC_SYSTICK_CURRENT_VALUE) = 0UL;
|
portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;
|
||||||
|
|
||||||
/* Configure SysTick to interrupt at the requested rate. */
|
/* Configure SysTick to interrupt at the requested rate. */
|
||||||
*(portNVIC_SYSTICK_LOAD) = ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;
|
portNVIC_SYSTICK_LOAD_REG = ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;
|
||||||
*(portNVIC_SYSTICK_CTRL) = portNVIC_SYSTICK_CLK | portNVIC_SYSTICK_INT | portNVIC_SYSTICK_ENABLE;
|
portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
|
||||||
}
|
}
|
||||||
/*-----------------------------------------------------------*/
|
/*-----------------------------------------------------------*/
|
||||||
|
|
||||||
|
#if( configUSE_TICKLESS_IDLE == 1 )
|
||||||
|
|
||||||
|
__weak void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime )
|
||||||
|
{
|
||||||
|
uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements;
|
||||||
|
TickType_t xModifiableIdleTime;
|
||||||
|
|
||||||
|
/* Make sure the SysTick reload value does not overflow the counter. */
|
||||||
|
if( xExpectedIdleTime > xMaximumPossibleSuppressedTicks )
|
||||||
|
{
|
||||||
|
xExpectedIdleTime = xMaximumPossibleSuppressedTicks;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Stop the SysTick momentarily. The time the SysTick is stopped for
|
||||||
|
is accounted for as best it can be, but using the tickless mode will
|
||||||
|
inevitably result in some tiny drift of the time maintained by the
|
||||||
|
kernel with respect to calendar time. */
|
||||||
|
portNVIC_SYSTICK_CTRL_REG &= ~portNVIC_SYSTICK_ENABLE_BIT;
|
||||||
|
|
||||||
|
/* Calculate the reload value required to wait xExpectedIdleTime
|
||||||
|
tick periods. -1 is used because this code will execute part way
|
||||||
|
through one of the tick periods. */
|
||||||
|
ulReloadValue = portNVIC_SYSTICK_CURRENT_VALUE_REG + ( ulTimerCountsForOneTick * ( xExpectedIdleTime - 1UL ) );
|
||||||
|
if( ulReloadValue > ulStoppedTimerCompensation )
|
||||||
|
{
|
||||||
|
ulReloadValue -= ulStoppedTimerCompensation;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Enter a critical section but don't use the taskENTER_CRITICAL()
|
||||||
|
method as that will mask interrupts that should exit sleep mode. */
|
||||||
|
__disable_interrupt();
|
||||||
|
__DSB();
|
||||||
|
__ISB();
|
||||||
|
|
||||||
|
/* If a context switch is pending or a task is waiting for the scheduler
|
||||||
|
to be unsuspended then abandon the low power entry. */
|
||||||
|
if( eTaskConfirmSleepModeStatus() == eAbortSleep )
|
||||||
|
{
|
||||||
|
/* Restart from whatever is left in the count register to complete
|
||||||
|
this tick period. */
|
||||||
|
portNVIC_SYSTICK_LOAD_REG = portNVIC_SYSTICK_CURRENT_VALUE_REG;
|
||||||
|
|
||||||
|
/* Restart SysTick. */
|
||||||
|
portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT;
|
||||||
|
|
||||||
|
/* Reset the reload register to the value required for normal tick
|
||||||
|
periods. */
|
||||||
|
portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL;
|
||||||
|
|
||||||
|
/* Re-enable interrupts - see comments above __disable_interrupt()
|
||||||
|
call above. */
|
||||||
|
__enable_interrupt();
|
||||||
|
}
|
||||||
|
else
|
||||||
|
{
|
||||||
|
/* Set the new reload value. */
|
||||||
|
portNVIC_SYSTICK_LOAD_REG = ulReloadValue;
|
||||||
|
|
||||||
|
/* Clear the SysTick count flag and set the count value back to
|
||||||
|
zero. */
|
||||||
|
portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;
|
||||||
|
|
||||||
|
/* Restart SysTick. */
|
||||||
|
portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT;
|
||||||
|
|
||||||
|
/* Sleep until something happens. configPRE_SLEEP_PROCESSING() can
|
||||||
|
set its parameter to 0 to indicate that its implementation contains
|
||||||
|
its own wait for interrupt or wait for event instruction, and so wfi
|
||||||
|
should not be executed again. However, the original expected idle
|
||||||
|
time variable must remain unmodified, so a copy is taken. */
|
||||||
|
xModifiableIdleTime = xExpectedIdleTime;
|
||||||
|
configPRE_SLEEP_PROCESSING( xModifiableIdleTime );
|
||||||
|
if( xModifiableIdleTime > 0 )
|
||||||
|
{
|
||||||
|
__DSB();
|
||||||
|
__WFI();
|
||||||
|
__ISB();
|
||||||
|
}
|
||||||
|
configPOST_SLEEP_PROCESSING( xExpectedIdleTime );
|
||||||
|
|
||||||
|
/* Re-enable interrupts to allow the interrupt that brought the MCU
|
||||||
|
out of sleep mode to execute immediately. see comments above
|
||||||
|
__disable_interrupt() call above. */
|
||||||
|
__enable_interrupt();
|
||||||
|
__DSB();
|
||||||
|
__ISB();
|
||||||
|
|
||||||
|
/* Disable interrupts again because the clock is about to be stopped
|
||||||
|
and interrupts that execute while the clock is stopped will increase
|
||||||
|
any slippage between the time maintained by the RTOS and calendar
|
||||||
|
time. */
|
||||||
|
__disable_interrupt();
|
||||||
|
__DSB();
|
||||||
|
__ISB();
|
||||||
|
|
||||||
|
/* Disable the SysTick clock without reading the
|
||||||
|
portNVIC_SYSTICK_CTRL_REG register to ensure the
|
||||||
|
portNVIC_SYSTICK_COUNT_FLAG_BIT is not cleared if it is set. Again,
|
||||||
|
the time the SysTick is stopped for is accounted for as best it can
|
||||||
|
be, but using the tickless mode will inevitably result in some tiny
|
||||||
|
drift of the time maintained by the kernel with respect to calendar
|
||||||
|
time*/
|
||||||
|
portNVIC_SYSTICK_CTRL_REG = ( portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT );
|
||||||
|
|
||||||
|
/* Determine if the SysTick clock has already counted to zero and
|
||||||
|
been set back to the current reload value (the reload back being
|
||||||
|
correct for the entire expected idle time) or if the SysTick is yet
|
||||||
|
to count to zero (in which case an interrupt other than the SysTick
|
||||||
|
must have brought the system out of sleep mode). */
|
||||||
|
if( ( portNVIC_SYSTICK_CTRL_REG & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 )
|
||||||
|
{
|
||||||
|
uint32_t ulCalculatedLoadValue;
|
||||||
|
|
||||||
|
/* The tick interrupt is already pending, and the SysTick count
|
||||||
|
reloaded with ulReloadValue. Reset the
|
||||||
|
portNVIC_SYSTICK_LOAD_REG with whatever remains of this tick
|
||||||
|
period. */
|
||||||
|
ulCalculatedLoadValue = ( ulTimerCountsForOneTick - 1UL ) - ( ulReloadValue - portNVIC_SYSTICK_CURRENT_VALUE_REG );
|
||||||
|
|
||||||
|
/* Don't allow a tiny value, or values that have somehow
|
||||||
|
underflowed because the post sleep hook did something
|
||||||
|
that took too long. */
|
||||||
|
if( ( ulCalculatedLoadValue < ulStoppedTimerCompensation ) || ( ulCalculatedLoadValue > ulTimerCountsForOneTick ) )
|
||||||
|
{
|
||||||
|
ulCalculatedLoadValue = ( ulTimerCountsForOneTick - 1UL );
|
||||||
|
}
|
||||||
|
|
||||||
|
portNVIC_SYSTICK_LOAD_REG = ulCalculatedLoadValue;
|
||||||
|
|
||||||
|
/* As the pending tick will be processed as soon as this
|
||||||
|
function exits, the tick value maintained by the tick is stepped
|
||||||
|
forward by one less than the time spent waiting. */
|
||||||
|
ulCompleteTickPeriods = xExpectedIdleTime - 1UL;
|
||||||
|
}
|
||||||
|
else
|
||||||
|
{
|
||||||
|
/* Something other than the tick interrupt ended the sleep.
|
||||||
|
Work out how long the sleep lasted rounded to complete tick
|
||||||
|
periods (not the ulReload value which accounted for part
|
||||||
|
ticks). */
|
||||||
|
ulCompletedSysTickDecrements = ( xExpectedIdleTime * ulTimerCountsForOneTick ) - portNVIC_SYSTICK_CURRENT_VALUE_REG ;
|
||||||
|
|
||||||
|
/* How many complete tick periods passed while the processor
|
||||||
|
was waiting? */
|
||||||
|
ulCompleteTickPeriods = ulCompletedSysTickDecrements / ulTimerCountsForOneTick;
|
||||||
|
|
||||||
|
/* The reload value is set to whatever fraction of a single tick
|
||||||
|
period remains. */
|
||||||
|
portNVIC_SYSTICK_LOAD_REG = ( ( ulCompleteTickPeriods + 1UL ) * ulTimerCountsForOneTick ) - ulCompletedSysTickDecrements;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Restart SysTick so it runs from portNVIC_SYSTICK_LOAD_REG
|
||||||
|
again, then set portNVIC_SYSTICK_LOAD_REG back to its standard
|
||||||
|
value. */
|
||||||
|
portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;
|
||||||
|
portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT;
|
||||||
|
vTaskStepTick( ulCompleteTickPeriods );
|
||||||
|
portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL;
|
||||||
|
|
||||||
|
/* Exit with interrpts enabled. */
|
||||||
|
__enable_interrupt();
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
#endif /* configUSE_TICKLESS_IDLE */
|
||||||
|
|
|
@ -103,6 +103,13 @@ extern void vClearInterruptMaskFromISR( uint32_t ulMask );
|
||||||
|
|
||||||
/*-----------------------------------------------------------*/
|
/*-----------------------------------------------------------*/
|
||||||
|
|
||||||
|
/* Tickless idle/low power functionality. */
|
||||||
|
#ifndef portSUPPRESS_TICKS_AND_SLEEP
|
||||||
|
extern void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime );
|
||||||
|
#define portSUPPRESS_TICKS_AND_SLEEP( xExpectedIdleTime ) vPortSuppressTicksAndSleep( xExpectedIdleTime )
|
||||||
|
#endif
|
||||||
|
/*-----------------------------------------------------------*/
|
||||||
|
|
||||||
/* Task function macros as described on the FreeRTOS.org WEB site. */
|
/* Task function macros as described on the FreeRTOS.org WEB site. */
|
||||||
#define portTASK_FUNCTION_PROTO( vFunction, pvParameters ) void vFunction( void *pvParameters )
|
#define portTASK_FUNCTION_PROTO( vFunction, pvParameters ) void vFunction( void *pvParameters )
|
||||||
#define portTASK_FUNCTION( vFunction, pvParameters ) void vFunction( void *pvParameters )
|
#define portTASK_FUNCTION( vFunction, pvParameters ) void vFunction( void *pvParameters )
|
||||||
|
|
|
@ -34,22 +34,33 @@
|
||||||
#include "task.h"
|
#include "task.h"
|
||||||
|
|
||||||
/* Constants required to manipulate the NVIC. */
|
/* Constants required to manipulate the NVIC. */
|
||||||
#define portNVIC_SYSTICK_CTRL ( ( volatile uint32_t * ) 0xe000e010 )
|
#define portNVIC_SYSTICK_CTRL_REG ( * ( ( volatile uint32_t * ) 0xe000e010 ) )
|
||||||
#define portNVIC_SYSTICK_LOAD ( ( volatile uint32_t * ) 0xe000e014 )
|
#define portNVIC_SYSTICK_LOAD_REG ( * ( ( volatile uint32_t * ) 0xe000e014 ) )
|
||||||
#define portNVIC_SYSTICK_CURRENT_VALUE ( ( volatile uint32_t * ) 0xe000e018 )
|
#define portNVIC_SYSTICK_CURRENT_VALUE_REG ( * ( ( volatile uint32_t * ) 0xe000e018 ) )
|
||||||
#define portNVIC_INT_CTRL ( ( volatile uint32_t *) 0xe000ed04 )
|
#define portNVIC_INT_CTRL_REG ( * ( ( volatile uint32_t * ) 0xe000ed04 ) )
|
||||||
#define portNVIC_SYSPRI2 ( ( volatile uint32_t *) 0xe000ed20 )
|
#define portNVIC_SYSPRI2_REG ( * ( ( volatile uint32_t * ) 0xe000ed20 ) )
|
||||||
#define portNVIC_SYSTICK_CLK 0x00000004
|
#define portNVIC_SYSTICK_CLK_BIT ( 1UL << 2UL )
|
||||||
#define portNVIC_SYSTICK_INT 0x00000002
|
#define portNVIC_SYSTICK_INT_BIT ( 1UL << 1UL )
|
||||||
#define portNVIC_SYSTICK_ENABLE 0x00000001
|
#define portNVIC_SYSTICK_ENABLE_BIT ( 1UL << 0UL )
|
||||||
#define portNVIC_PENDSVSET 0x10000000
|
#define portNVIC_SYSTICK_COUNT_FLAG_BIT ( 1UL << 16UL )
|
||||||
#define portMIN_INTERRUPT_PRIORITY ( 255UL )
|
#define portNVIC_PENDSVSET_BIT ( 1UL << 28UL )
|
||||||
#define portNVIC_PENDSV_PRI ( portMIN_INTERRUPT_PRIORITY << 16UL )
|
#define portMIN_INTERRUPT_PRIORITY ( 255UL )
|
||||||
#define portNVIC_SYSTICK_PRI ( portMIN_INTERRUPT_PRIORITY << 24UL )
|
#define portNVIC_PENDSV_PRI ( portMIN_INTERRUPT_PRIORITY << 16UL )
|
||||||
|
#define portNVIC_SYSTICK_PRI ( portMIN_INTERRUPT_PRIORITY << 24UL )
|
||||||
|
|
||||||
/* Constants required to set up the initial stack. */
|
/* Constants required to set up the initial stack. */
|
||||||
#define portINITIAL_XPSR ( 0x01000000 )
|
#define portINITIAL_XPSR ( 0x01000000 )
|
||||||
|
|
||||||
|
/* The systick is a 24-bit counter. */
|
||||||
|
#define portMAX_24_BIT_NUMBER ( 0xffffffUL )
|
||||||
|
|
||||||
|
/* A fiddle factor to estimate the number of SysTick counts that would have
|
||||||
|
occurred while the SysTick counter is stopped during tickless idle
|
||||||
|
calculations. */
|
||||||
|
#ifndef portMISSED_COUNTS_FACTOR
|
||||||
|
#define portMISSED_COUNTS_FACTOR ( 45UL )
|
||||||
|
#endif
|
||||||
|
|
||||||
/* Constants used with memory barrier intrinsics. */
|
/* Constants used with memory barrier intrinsics. */
|
||||||
#define portSY_FULL_READ_WRITE ( 15 )
|
#define portSY_FULL_READ_WRITE ( 15 )
|
||||||
|
|
||||||
|
@ -57,6 +68,24 @@
|
||||||
variable. */
|
variable. */
|
||||||
static UBaseType_t uxCriticalNesting = 0xaaaaaaaa;
|
static UBaseType_t uxCriticalNesting = 0xaaaaaaaa;
|
||||||
|
|
||||||
|
/* The number of SysTick increments that make up one tick period. */
|
||||||
|
#if( configUSE_TICKLESS_IDLE == 1 )
|
||||||
|
static uint32_t ulTimerCountsForOneTick = 0;
|
||||||
|
#endif /* configUSE_TICKLESS_IDLE */
|
||||||
|
|
||||||
|
/* The maximum number of tick periods that can be suppressed is limited by the
|
||||||
|
24 bit resolution of the SysTick timer. */
|
||||||
|
#if( configUSE_TICKLESS_IDLE == 1 )
|
||||||
|
static uint32_t xMaximumPossibleSuppressedTicks = 0;
|
||||||
|
#endif /* configUSE_TICKLESS_IDLE */
|
||||||
|
|
||||||
|
/* Compensate for the CPU cycles that pass while the SysTick is stopped (low
|
||||||
|
power functionality only.
|
||||||
|
*/
|
||||||
|
#if( configUSE_TICKLESS_IDLE == 1 )
|
||||||
|
static uint32_t ulStoppedTimerCompensation = 0;
|
||||||
|
#endif /* configUSE_TICKLESS_IDLE */
|
||||||
|
|
||||||
/*
|
/*
|
||||||
* Setup the timer to generate the tick interrupts.
|
* Setup the timer to generate the tick interrupts.
|
||||||
*/
|
*/
|
||||||
|
@ -158,8 +187,8 @@ __asm void prvPortStartFirstTask( void )
|
||||||
BaseType_t xPortStartScheduler( void )
|
BaseType_t xPortStartScheduler( void )
|
||||||
{
|
{
|
||||||
/* Make PendSV, CallSV and SysTick the same priority as the kernel. */
|
/* Make PendSV, CallSV and SysTick the same priority as the kernel. */
|
||||||
*(portNVIC_SYSPRI2) |= portNVIC_PENDSV_PRI;
|
portNVIC_SYSPRI2_REG |= portNVIC_PENDSV_PRI;
|
||||||
*(portNVIC_SYSPRI2) |= portNVIC_SYSTICK_PRI;
|
portNVIC_SYSPRI2_REG |= portNVIC_SYSTICK_PRI;
|
||||||
|
|
||||||
/* Start the timer that generates the tick ISR. Interrupts are disabled
|
/* Start the timer that generates the tick ISR. Interrupts are disabled
|
||||||
here already. */
|
here already. */
|
||||||
|
@ -187,7 +216,7 @@ void vPortEndScheduler( void )
|
||||||
void vPortYield( void )
|
void vPortYield( void )
|
||||||
{
|
{
|
||||||
/* Set a PendSV to request a context switch. */
|
/* Set a PendSV to request a context switch. */
|
||||||
*( portNVIC_INT_CTRL ) = portNVIC_PENDSVSET;
|
portNVIC_INT_CTRL_REG = portNVIC_PENDSVSET_BIT;
|
||||||
|
|
||||||
/* Barriers are normally not required but do ensure the code is completely
|
/* Barriers are normally not required but do ensure the code is completely
|
||||||
within the specified behaviour for the architecture. */
|
within the specified behaviour for the architecture. */
|
||||||
|
@ -287,7 +316,7 @@ uint32_t ulPreviousMask;
|
||||||
if( xTaskIncrementTick() != pdFALSE )
|
if( xTaskIncrementTick() != pdFALSE )
|
||||||
{
|
{
|
||||||
/* Pend a context switch. */
|
/* Pend a context switch. */
|
||||||
*(portNVIC_INT_CTRL) = portNVIC_PENDSVSET;
|
portNVIC_INT_CTRL_REG = portNVIC_PENDSVSET_BIT;
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
portCLEAR_INTERRUPT_MASK_FROM_ISR( ulPreviousMask );
|
portCLEAR_INTERRUPT_MASK_FROM_ISR( ulPreviousMask );
|
||||||
|
@ -300,13 +329,187 @@ uint32_t ulPreviousMask;
|
||||||
*/
|
*/
|
||||||
void prvSetupTimerInterrupt( void )
|
void prvSetupTimerInterrupt( void )
|
||||||
{
|
{
|
||||||
|
/* Calculate the constants required to configure the tick interrupt. */
|
||||||
|
#if( configUSE_TICKLESS_IDLE == 1 )
|
||||||
|
ulTimerCountsForOneTick = ( configCPU_CLOCK_HZ / configTICK_RATE_HZ );
|
||||||
|
xMaximumPossibleSuppressedTicks = portMAX_24_BIT_NUMBER / ulTimerCountsForOneTick;
|
||||||
|
ulStoppedTimerCompensation = portMISSED_COUNTS_FACTOR;
|
||||||
|
#endif /* configUSE_TICKLESS_IDLE */
|
||||||
|
|
||||||
/* Stop and reset the SysTick. */
|
/* Stop and reset the SysTick. */
|
||||||
*(portNVIC_SYSTICK_CTRL) = 0UL;
|
portNVIC_SYSTICK_CTRL_REG = 0UL;
|
||||||
*(portNVIC_SYSTICK_CURRENT_VALUE) = 0UL;
|
portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;
|
||||||
|
|
||||||
/* Configure SysTick to interrupt at the requested rate. */
|
/* Configure SysTick to interrupt at the requested rate. */
|
||||||
*(portNVIC_SYSTICK_LOAD) = ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;
|
portNVIC_SYSTICK_LOAD_REG = ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;
|
||||||
*(portNVIC_SYSTICK_CTRL) = portNVIC_SYSTICK_CLK | portNVIC_SYSTICK_INT | portNVIC_SYSTICK_ENABLE;
|
portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
|
||||||
}
|
}
|
||||||
/*-----------------------------------------------------------*/
|
/*-----------------------------------------------------------*/
|
||||||
|
|
||||||
|
#if( configUSE_TICKLESS_IDLE == 1 )
|
||||||
|
|
||||||
|
__weak void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime )
|
||||||
|
{
|
||||||
|
uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements;
|
||||||
|
TickType_t xModifiableIdleTime;
|
||||||
|
|
||||||
|
/* Make sure the SysTick reload value does not overflow the counter. */
|
||||||
|
if( xExpectedIdleTime > xMaximumPossibleSuppressedTicks )
|
||||||
|
{
|
||||||
|
xExpectedIdleTime = xMaximumPossibleSuppressedTicks;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Stop the SysTick momentarily. The time the SysTick is stopped for
|
||||||
|
is accounted for as best it can be, but using the tickless mode will
|
||||||
|
inevitably result in some tiny drift of the time maintained by the
|
||||||
|
kernel with respect to calendar time. */
|
||||||
|
portNVIC_SYSTICK_CTRL_REG &= ~portNVIC_SYSTICK_ENABLE_BIT;
|
||||||
|
|
||||||
|
/* Calculate the reload value required to wait xExpectedIdleTime
|
||||||
|
tick periods. -1 is used because this code will execute part way
|
||||||
|
through one of the tick periods. */
|
||||||
|
ulReloadValue = portNVIC_SYSTICK_CURRENT_VALUE_REG + ( ulTimerCountsForOneTick * ( xExpectedIdleTime - 1UL ) );
|
||||||
|
if( ulReloadValue > ulStoppedTimerCompensation )
|
||||||
|
{
|
||||||
|
ulReloadValue -= ulStoppedTimerCompensation;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Enter a critical section but don't use the taskENTER_CRITICAL()
|
||||||
|
method as that will mask interrupts that should exit sleep mode. */
|
||||||
|
__disable_irq();
|
||||||
|
__dsb( portSY_FULL_READ_WRITE );
|
||||||
|
__isb( portSY_FULL_READ_WRITE );
|
||||||
|
|
||||||
|
/* If a context switch is pending or a task is waiting for the scheduler
|
||||||
|
to be unsuspended then abandon the low power entry. */
|
||||||
|
if( eTaskConfirmSleepModeStatus() == eAbortSleep )
|
||||||
|
{
|
||||||
|
/* Restart from whatever is left in the count register to complete
|
||||||
|
this tick period. */
|
||||||
|
portNVIC_SYSTICK_LOAD_REG = portNVIC_SYSTICK_CURRENT_VALUE_REG;
|
||||||
|
|
||||||
|
/* Restart SysTick. */
|
||||||
|
portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT;
|
||||||
|
|
||||||
|
/* Reset the reload register to the value required for normal tick
|
||||||
|
periods. */
|
||||||
|
portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL;
|
||||||
|
|
||||||
|
/* Re-enable interrupts - see comments above __disable_irq() call
|
||||||
|
above. */
|
||||||
|
__enable_irq();
|
||||||
|
}
|
||||||
|
else
|
||||||
|
{
|
||||||
|
/* Set the new reload value. */
|
||||||
|
portNVIC_SYSTICK_LOAD_REG = ulReloadValue;
|
||||||
|
|
||||||
|
/* Clear the SysTick count flag and set the count value back to
|
||||||
|
zero. */
|
||||||
|
portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;
|
||||||
|
|
||||||
|
/* Restart SysTick. */
|
||||||
|
portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT;
|
||||||
|
|
||||||
|
/* Sleep until something happens. configPRE_SLEEP_PROCESSING() can
|
||||||
|
set its parameter to 0 to indicate that its implementation contains
|
||||||
|
its own wait for interrupt or wait for event instruction, and so wfi
|
||||||
|
should not be executed again. However, the original expected idle
|
||||||
|
time variable must remain unmodified, so a copy is taken. */
|
||||||
|
xModifiableIdleTime = xExpectedIdleTime;
|
||||||
|
configPRE_SLEEP_PROCESSING( xModifiableIdleTime );
|
||||||
|
if( xModifiableIdleTime > 0 )
|
||||||
|
{
|
||||||
|
__dsb( portSY_FULL_READ_WRITE );
|
||||||
|
__wfi();
|
||||||
|
__isb( portSY_FULL_READ_WRITE );
|
||||||
|
}
|
||||||
|
configPOST_SLEEP_PROCESSING( xExpectedIdleTime );
|
||||||
|
|
||||||
|
/* Re-enable interrupts to allow the interrupt that brought the MCU
|
||||||
|
out of sleep mode to execute immediately. see comments above
|
||||||
|
__disable_interrupt() call above. */
|
||||||
|
__enable_irq();
|
||||||
|
__dsb( portSY_FULL_READ_WRITE );
|
||||||
|
__isb( portSY_FULL_READ_WRITE );
|
||||||
|
|
||||||
|
/* Disable interrupts again because the clock is about to be stopped
|
||||||
|
and interrupts that execute while the clock is stopped will increase
|
||||||
|
any slippage between the time maintained by the RTOS and calendar
|
||||||
|
time. */
|
||||||
|
__disable_irq();
|
||||||
|
__dsb( portSY_FULL_READ_WRITE );
|
||||||
|
__isb( portSY_FULL_READ_WRITE );
|
||||||
|
|
||||||
|
/* Disable the SysTick clock without reading the
|
||||||
|
portNVIC_SYSTICK_CTRL_REG register to ensure the
|
||||||
|
portNVIC_SYSTICK_COUNT_FLAG_BIT is not cleared if it is set. Again,
|
||||||
|
the time the SysTick is stopped for is accounted for as best it can
|
||||||
|
be, but using the tickless mode will inevitably result in some tiny
|
||||||
|
drift of the time maintained by the kernel with respect to calendar
|
||||||
|
time*/
|
||||||
|
portNVIC_SYSTICK_CTRL_REG = ( portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT );
|
||||||
|
|
||||||
|
/* Determine if the SysTick clock has already counted to zero and
|
||||||
|
been set back to the current reload value (the reload back being
|
||||||
|
correct for the entire expected idle time) or if the SysTick is yet
|
||||||
|
to count to zero (in which case an interrupt other than the SysTick
|
||||||
|
must have brought the system out of sleep mode). */
|
||||||
|
if( ( portNVIC_SYSTICK_CTRL_REG & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 )
|
||||||
|
{
|
||||||
|
uint32_t ulCalculatedLoadValue;
|
||||||
|
|
||||||
|
/* The tick interrupt is already pending, and the SysTick count
|
||||||
|
reloaded with ulReloadValue. Reset the
|
||||||
|
portNVIC_SYSTICK_LOAD with whatever remains of this tick
|
||||||
|
period. */
|
||||||
|
ulCalculatedLoadValue = ( ulTimerCountsForOneTick - 1UL ) - ( ulReloadValue - portNVIC_SYSTICK_CURRENT_VALUE_REG );
|
||||||
|
|
||||||
|
/* Don't allow a tiny value, or values that have somehow
|
||||||
|
underflowed because the post sleep hook did something
|
||||||
|
that took too long. */
|
||||||
|
if( ( ulCalculatedLoadValue < ulStoppedTimerCompensation ) || ( ulCalculatedLoadValue > ulTimerCountsForOneTick ) )
|
||||||
|
{
|
||||||
|
ulCalculatedLoadValue = ( ulTimerCountsForOneTick - 1UL );
|
||||||
|
}
|
||||||
|
|
||||||
|
portNVIC_SYSTICK_LOAD_REG = ulCalculatedLoadValue;
|
||||||
|
|
||||||
|
/* As the pending tick will be processed as soon as this
|
||||||
|
function exits, the tick value maintained by the tick is stepped
|
||||||
|
forward by one less than the time spent waiting. */
|
||||||
|
ulCompleteTickPeriods = xExpectedIdleTime - 1UL;
|
||||||
|
}
|
||||||
|
else
|
||||||
|
{
|
||||||
|
/* Something other than the tick interrupt ended the sleep.
|
||||||
|
Work out how long the sleep lasted rounded to complete tick
|
||||||
|
periods (not the ulReload value which accounted for part
|
||||||
|
ticks). */
|
||||||
|
ulCompletedSysTickDecrements = ( xExpectedIdleTime * ulTimerCountsForOneTick ) - portNVIC_SYSTICK_CURRENT_VALUE_REG;
|
||||||
|
|
||||||
|
/* How many complete tick periods passed while the processor
|
||||||
|
was waiting? */
|
||||||
|
ulCompleteTickPeriods = ulCompletedSysTickDecrements / ulTimerCountsForOneTick;
|
||||||
|
|
||||||
|
/* The reload value is set to whatever fraction of a single tick
|
||||||
|
period remains. */
|
||||||
|
portNVIC_SYSTICK_LOAD_REG = ( ( ulCompleteTickPeriods + 1UL ) * ulTimerCountsForOneTick ) - ulCompletedSysTickDecrements;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Restart SysTick so it runs from portNVIC_SYSTICK_LOAD
|
||||||
|
again, then set portNVIC_SYSTICK_LOAD back to its standard
|
||||||
|
value. */
|
||||||
|
portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;
|
||||||
|
portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT;
|
||||||
|
vTaskStepTick( ulCompleteTickPeriods );
|
||||||
|
portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL;
|
||||||
|
|
||||||
|
/* Exit with interrpts enabled. */
|
||||||
|
__enable_irq();
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
#endif /* #if configUSE_TICKLESS_IDLE */
|
||||||
|
|
||||||
|
/*-----------------------------------------------------------*/
|
||||||
|
|
|
@ -100,6 +100,13 @@ extern void vClearInterruptMaskFromISR( uint32_t ulMask );
|
||||||
|
|
||||||
/*-----------------------------------------------------------*/
|
/*-----------------------------------------------------------*/
|
||||||
|
|
||||||
|
/* Tickless idle/low power functionality. */
|
||||||
|
#ifndef portSUPPRESS_TICKS_AND_SLEEP
|
||||||
|
extern void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime );
|
||||||
|
#define portSUPPRESS_TICKS_AND_SLEEP( xExpectedIdleTime ) vPortSuppressTicksAndSleep( xExpectedIdleTime )
|
||||||
|
#endif
|
||||||
|
/*-----------------------------------------------------------*/
|
||||||
|
|
||||||
/* Task function macros as described on the FreeRTOS.org WEB site. */
|
/* Task function macros as described on the FreeRTOS.org WEB site. */
|
||||||
#define portTASK_FUNCTION_PROTO( vFunction, pvParameters ) void vFunction( void *pvParameters )
|
#define portTASK_FUNCTION_PROTO( vFunction, pvParameters ) void vFunction( void *pvParameters )
|
||||||
#define portTASK_FUNCTION( vFunction, pvParameters ) void vFunction( void *pvParameters )
|
#define portTASK_FUNCTION( vFunction, pvParameters ) void vFunction( void *pvParameters )
|
||||||
|
|
Loading…
Reference in a new issue