From: rtel Date: Tue, 28 Mar 2017 03:13:48 +0000 (+0000) Subject: Updates to the Cortex-M tickless idle code to reduce clock slippage. X-Git-Tag: V10.0.0~26 X-Git-Url: https://git.sur5r.net/?a=commitdiff_plain;h=959ed52cbe608243fc2452b6cc7f39348108d218;p=freertos Updates to the Cortex-M tickless idle code to reduce clock slippage. Updates to prevent the vTaskSwitchContext() function being removed from GCC builds when link time optimisation is used. git-svn-id: https://svn.code.sf.net/p/freertos/code/trunk@2493 1d2547de-c912-0410-9cb9-b8ca96c0e9e2 --- diff --git a/FreeRTOS/Source/portable/CCS/ARM_CM3/port.c b/FreeRTOS/Source/portable/CCS/ARM_CM3/port.c index 7ec544e04..0fc1a6271 100644 --- a/FreeRTOS/Source/portable/CCS/ARM_CM3/port.c +++ b/FreeRTOS/Source/portable/CCS/ARM_CM3/port.c @@ -75,7 +75,7 @@ #include "FreeRTOS.h" #include "task.h" -#if configMAX_SYSCALL_INTERRUPT_PRIORITY == 0 +#if( configMAX_SYSCALL_INTERRUPT_PRIORITY == 0 ) #error configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to 0. See http://www.FreeRTOS.org/RTOS-Cortex-M3-M4.html #endif @@ -132,14 +132,6 @@ calculations. */ have bit-0 clear, as it is loaded into the PC on exit from an ISR. */ #define portSTART_ADDRESS_MASK ( ( StackType_t ) 0xfffffffeUL ) -/* Required to allow portasm.asm access the configMAX_SYSCALL_INTERRUPT_PRIORITY -setting. */ -const uint32_t ulMaxSyscallInterruptPriority = configMAX_SYSCALL_INTERRUPT_PRIORITY; - -/* Each task maintains its own interrupt status in the critical nesting -variable. */ -static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; - /* * Setup the timer to generate the tick interrupts. The implementation in this * file is weak to allow application writers to change the timer used to @@ -164,10 +156,18 @@ static void prvTaskExitError( void ); /*-----------------------------------------------------------*/ +/* Required to allow portasm.asm access the configMAX_SYSCALL_INTERRUPT_PRIORITY +setting. */ +const uint32_t ulMaxSyscallInterruptPriority = configMAX_SYSCALL_INTERRUPT_PRIORITY; + +/* Each task maintains its own interrupt status in the critical nesting +variable. */ +static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; + /* * The number of SysTick increments that make up one tick period. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulTimerCountsForOneTick = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -175,7 +175,7 @@ static void prvTaskExitError( void ); * 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 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t xMaximumPossibleSuppressedTicks = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -183,7 +183,7 @@ static void prvTaskExitError( void ); * Compensate for the CPU cycles that pass while the SysTick is stopped (low * power functionality only. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulStoppedTimerCompensation = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -384,12 +384,12 @@ void xPortSysTickHandler( void ) } /*-----------------------------------------------------------*/ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) #pragma WEAK( vPortSuppressTicksAndSleep ) void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime ) { - uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements, ulSysTickCTRL; + uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements; TickType_t xModifiableIdleTime; /* Make sure the SysTick reload value does not overflow the counter. */ @@ -466,23 +466,41 @@ void xPortSysTickHandler( void ) } configPOST_SLEEP_PROCESSING( xExpectedIdleTime ); - /* Stop SysTick. 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. */ - ulSysTickCTRL = portNVIC_SYSTICK_CTRL_REG; - portNVIC_SYSTICK_CTRL_REG = ( ulSysTickCTRL & ~portNVIC_SYSTICK_ENABLE_BIT ); - - /* Re-enable interrupts - see comments above __disable_interrupt() - call above. */ + /* 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. */ __asm( " cpsie i" ); - - if( ( ulSysTickCTRL & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 ) + __asm( " dsb" ); + __asm( " 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. */ + __asm( " cpsid i" ); + __asm( " dsb" ); + __asm( " 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 has already executed, and the SysTick - count reloaded with ulReloadValue. Reset the + /* 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 ); @@ -497,11 +515,9 @@ void xPortSysTickHandler( void ) portNVIC_SYSTICK_LOAD_REG = ulCalculatedLoadValue; - /* The tick interrupt handler will already have pended the tick - processing in the kernel. 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. */ + /* 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 @@ -523,21 +539,18 @@ void xPortSysTickHandler( void ) /* Restart SysTick so it runs from portNVIC_SYSTICK_LOAD_REG again, then set portNVIC_SYSTICK_LOAD_REG back to its standard - value. The critical section is used to ensure the tick interrupt - can only execute once in the case that the reload register is near - zero. */ + value. */ portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL; - portENTER_CRITICAL(); - { - portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; - vTaskStepTick( ulCompleteTickPeriods ); - portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; - } - portEXIT_CRITICAL(); + portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; + vTaskStepTick( ulCompleteTickPeriods ); + portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; + + /* Exit with interrpts enabled. */ + __asm( " cpsie i" ); } } -#endif /* #if configUSE_TICKLESS_IDLE */ +#endif /* configUSE_TICKLESS_IDLE */ /*-----------------------------------------------------------*/ /* @@ -620,7 +633,7 @@ void vPortSetupTimerInterrupt( void ) devices by calling NVIC_SetPriorityGrouping( 0 ); before starting the scheduler. Note however that some vendor specific peripheral libraries assume a non-zero priority group setting, in which cases using a value - of zero will result in unpredicable behaviour. */ + of zero will result in unpredictable behaviour. */ configASSERT( ( portAIRCR_REG & portPRIORITY_GROUP_MASK ) <= ulMaxPRIGROUPValue ); } diff --git a/FreeRTOS/Source/portable/CCS/ARM_CM4F/port.c b/FreeRTOS/Source/portable/CCS/ARM_CM4F/port.c index d00990171..9457be19a 100644 --- a/FreeRTOS/Source/portable/CCS/ARM_CM4F/port.c +++ b/FreeRTOS/Source/portable/CCS/ARM_CM4F/port.c @@ -79,7 +79,7 @@ #error This port can only be used when the project options are configured to enable hardware floating point support. #endif -#if configMAX_SYSCALL_INTERRUPT_PRIORITY == 0 +#if( configMAX_SYSCALL_INTERRUPT_PRIORITY == 0 ) #error configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to 0. See http://www.FreeRTOS.org/RTOS-Cortex-M3-M4.html #endif @@ -141,14 +141,6 @@ calculations. */ have bit-0 clear, as it is loaded into the PC on exit from an ISR. */ #define portSTART_ADDRESS_MASK ( ( StackType_t ) 0xfffffffeUL ) -/* Required to allow portasm.asm access the configMAX_SYSCALL_INTERRUPT_PRIORITY -setting. */ -const uint32_t ulMaxSyscallInterruptPriority = configMAX_SYSCALL_INTERRUPT_PRIORITY; - -/* Each task maintains its own interrupt status in the critical nesting -variable. */ -static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; - /* * Setup the timer to generate the tick interrupts. The implementation in this * file is weak to allow application writers to change the timer used to @@ -178,10 +170,18 @@ static void prvTaskExitError( void ); /*-----------------------------------------------------------*/ +/* Required to allow portasm.asm access the configMAX_SYSCALL_INTERRUPT_PRIORITY +setting. */ +const uint32_t ulMaxSyscallInterruptPriority = configMAX_SYSCALL_INTERRUPT_PRIORITY; + +/* Each task maintains its own interrupt status in the critical nesting +variable. */ +static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; + /* * The number of SysTick increments that make up one tick period. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulTimerCountsForOneTick = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -189,7 +189,7 @@ static void prvTaskExitError( void ); * 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 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t xMaximumPossibleSuppressedTicks = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -197,7 +197,7 @@ static void prvTaskExitError( void ); * Compensate for the CPU cycles that pass while the SysTick is stopped (low * power functionality only. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulStoppedTimerCompensation = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -409,12 +409,12 @@ void xPortSysTickHandler( void ) } /*-----------------------------------------------------------*/ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) #pragma WEAK( vPortSuppressTicksAndSleep ) void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime ) { - uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements, ulSysTickCTRL; + uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements; TickType_t xModifiableIdleTime; /* Make sure the SysTick reload value does not overflow the counter. */ @@ -491,23 +491,41 @@ void xPortSysTickHandler( void ) } configPOST_SLEEP_PROCESSING( xExpectedIdleTime ); - /* Stop SysTick. 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. */ - ulSysTickCTRL = portNVIC_SYSTICK_CTRL_REG; - portNVIC_SYSTICK_CTRL_REG = ( ulSysTickCTRL & ~portNVIC_SYSTICK_ENABLE_BIT ); - - /* Re-enable interrupts - see comments above __disable_interrupt() - call above. */ + /* 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. */ __asm( " cpsie i" ); - - if( ( ulSysTickCTRL & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 ) + __asm( " dsb" ); + __asm( " 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. */ + __asm( " cpsid i" ); + __asm( " dsb" ); + __asm( " 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 has already executed, and the SysTick - count reloaded with ulReloadValue. Reset the + /* 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 ); @@ -522,11 +540,9 @@ void xPortSysTickHandler( void ) portNVIC_SYSTICK_LOAD_REG = ulCalculatedLoadValue; - /* The tick interrupt handler will already have pended the tick - processing in the kernel. 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. */ + /* 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 @@ -548,21 +564,18 @@ void xPortSysTickHandler( void ) /* Restart SysTick so it runs from portNVIC_SYSTICK_LOAD_REG again, then set portNVIC_SYSTICK_LOAD_REG back to its standard - value. The critical section is used to ensure the tick interrupt - can only execute once in the case that the reload register is near - zero. */ + value. */ portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL; - portENTER_CRITICAL(); - { - portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; - vTaskStepTick( ulCompleteTickPeriods ); - portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; - } - portEXIT_CRITICAL(); + portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; + vTaskStepTick( ulCompleteTickPeriods ); + portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; + + /* Exit with interrpts enabled. */ + __asm( " cpsie i" ); } } -#endif /* #if configUSE_TICKLESS_IDLE */ +#endif /* configUSE_TICKLESS_IDLE */ /*-----------------------------------------------------------*/ /* @@ -573,7 +586,7 @@ void xPortSysTickHandler( void ) void vPortSetupTimerInterrupt( void ) { /* Calculate the constants required to configure the tick interrupt. */ - #if configUSE_TICKLESS_IDLE == 1 + #if( configUSE_TICKLESS_IDLE == 1 ) { ulTimerCountsForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ); xMaximumPossibleSuppressedTicks = portMAX_24_BIT_NUMBER / ulTimerCountsForOneTick; @@ -645,7 +658,7 @@ void vPortSetupTimerInterrupt( void ) devices by calling NVIC_SetPriorityGrouping( 0 ); before starting the scheduler. Note however that some vendor specific peripheral libraries assume a non-zero priority group setting, in which cases using a value - of zero will result in unpredicable behaviour. */ + of zero will result in unpredictable behaviour. */ configASSERT( ( portAIRCR_REG & portPRIORITY_GROUP_MASK ) <= ulMaxPRIGROUPValue ); } diff --git a/FreeRTOS/Source/portable/GCC/ARM_CM0/port.c b/FreeRTOS/Source/portable/GCC/ARM_CM0/port.c index 559883f58..c4c768bea 100644 --- a/FreeRTOS/Source/portable/GCC/ARM_CM0/port.c +++ b/FreeRTOS/Source/portable/GCC/ARM_CM0/port.c @@ -101,10 +101,6 @@ debugger. */ #define portTASK_RETURN_ADDRESS prvTaskExitError #endif -/* Each task maintains its own interrupt status in the critical nesting -variable. */ -static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; - /* * Setup the timer to generate the tick interrupts. */ @@ -129,6 +125,12 @@ static void prvTaskExitError( void ); /*-----------------------------------------------------------*/ +/* Each task maintains its own interrupt status in the critical nesting +variable. */ +static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; + +/*-----------------------------------------------------------*/ + /* * See header file for description. */ @@ -220,8 +222,11 @@ BaseType_t xPortStartScheduler( void ) /* Should never get here as the tasks will now be executing! Call the task exit error function to prevent compiler warnings about a static function not being called in the case that the application writer overrides this - functionality by defining configTASK_RETURN_ADDRESS. */ + functionality by defining configTASK_RETURN_ADDRESS. Call + vTaskSwitchContext() so link time optimisation does not remove the + symbol. */ prvTaskExitError(); + vTaskSwitchContext(); /* Should not get here! */ return 0; diff --git a/FreeRTOS/Source/portable/GCC/ARM_CM3/port.c b/FreeRTOS/Source/portable/GCC/ARM_CM3/port.c index ba512f0b4..1317a387e 100644 --- a/FreeRTOS/Source/portable/GCC/ARM_CM3/port.c +++ b/FreeRTOS/Source/portable/GCC/ARM_CM3/port.c @@ -144,10 +144,6 @@ debugger. */ #define portTASK_RETURN_ADDRESS prvTaskExitError #endif -/* Each task maintains its own interrupt status in the critical nesting -variable. */ -static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; - /* * Setup the timer to generate the tick interrupts. The implementation in this * file is weak to allow application writers to change the timer used to @@ -174,10 +170,14 @@ static void prvTaskExitError( void ); /*-----------------------------------------------------------*/ +/* Each task maintains its own interrupt status in the critical nesting +variable. */ +static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; + /* * The number of SysTick increments that make up one tick period. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulTimerCountsForOneTick = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -185,7 +185,7 @@ static void prvTaskExitError( void ); * 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 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t xMaximumPossibleSuppressedTicks = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -193,7 +193,7 @@ static void prvTaskExitError( void ); * Compensate for the CPU cycles that pass while the SysTick is stopped (low * power functionality only. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulStoppedTimerCompensation = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -202,7 +202,7 @@ static void prvTaskExitError( void ); * FreeRTOS API functions are not called from interrupts that have been assigned * a priority above configMAX_SYSCALL_INTERRUPT_PRIORITY. */ -#if ( configASSERT_DEFINED == 1 ) +#if( configASSERT_DEFINED == 1 ) static uint8_t ucMaxSysCallPriority = 0; static uint32_t ulMaxPRIGROUPValue = 0; static const volatile uint8_t * const pcInterruptPriorityRegisters = ( const volatile uint8_t * const ) portNVIC_IP_REGISTERS_OFFSET_16; @@ -370,8 +370,11 @@ BaseType_t xPortStartScheduler( void ) /* Should never get here as the tasks will now be executing! Call the task exit error function to prevent compiler warnings about a static function not being called in the case that the application writer overrides this - functionality by defining configTASK_RETURN_ADDRESS. */ + functionality by defining configTASK_RETURN_ADDRESS. Call + vTaskSwitchContext() so link time optimisation does not remove the + symbol. */ prvTaskExitError(); + vTaskSwitchContext(); /* Should not get here! */ return 0; @@ -471,7 +474,7 @@ void xPortSysTickHandler( void ) } /*-----------------------------------------------------------*/ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) __attribute__((weak)) void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime ) { @@ -551,13 +554,28 @@ void xPortSysTickHandler( void ) } configPOST_SLEEP_PROCESSING( xExpectedIdleTime ); - /* Re-enable interrupts - see comments above the cpsid instruction() - above. */ + /* 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. */ __asm volatile( "cpsie i" ::: "memory" ); + __asm volatile( "dsb" ); + __asm volatile( "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. */ + __asm volatile( "cpsid i" ::: "memory" ); + __asm volatile( "dsb" ); + __asm volatile( "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. */ + 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 @@ -569,8 +587,8 @@ void xPortSysTickHandler( void ) { uint32_t ulCalculatedLoadValue; - /* The tick interrupt has already executed, and the SysTick - count reloaded with ulReloadValue. Reset the + /* 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 ); @@ -585,11 +603,9 @@ void xPortSysTickHandler( void ) portNVIC_SYSTICK_LOAD_REG = ulCalculatedLoadValue; - /* The tick interrupt handler will already have pended the tick - processing in the kernel. 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. */ + /* 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 @@ -611,21 +627,18 @@ void xPortSysTickHandler( void ) /* Restart SysTick so it runs from portNVIC_SYSTICK_LOAD_REG again, then set portNVIC_SYSTICK_LOAD_REG back to its standard - value. The critical section is used to ensure the tick interrupt - can only execute once in the case that the reload register is near - zero. */ + value. */ portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL; - portENTER_CRITICAL(); - { - portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; - vTaskStepTick( ulCompleteTickPeriods ); - portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; - } - portEXIT_CRITICAL(); + portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; + vTaskStepTick( ulCompleteTickPeriods ); + portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; + + /* Exit with interrpts enabled. */ + __asm volatile( "cpsie i" ::: "memory" ); } } -#endif /* #if configUSE_TICKLESS_IDLE */ +#endif /* configUSE_TICKLESS_IDLE */ /*-----------------------------------------------------------*/ /* @@ -635,7 +648,7 @@ void xPortSysTickHandler( void ) __attribute__(( weak )) void vPortSetupTimerInterrupt( void ) { /* Calculate the constants required to configure the tick interrupt. */ - #if configUSE_TICKLESS_IDLE == 1 + #if( configUSE_TICKLESS_IDLE == 1 ) { ulTimerCountsForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ); xMaximumPossibleSuppressedTicks = portMAX_24_BIT_NUMBER / ulTimerCountsForOneTick; @@ -707,7 +720,7 @@ __attribute__(( weak )) void vPortSetupTimerInterrupt( void ) devices by calling NVIC_SetPriorityGrouping( 0 ); before starting the scheduler. Note however that some vendor specific peripheral libraries assume a non-zero priority group setting, in which cases using a value - of zero will result in unpredicable behaviour. */ + of zero will result in unpredictable behaviour. */ configASSERT( ( portAIRCR_REG & portPRIORITY_GROUP_MASK ) <= ulMaxPRIGROUPValue ); } diff --git a/FreeRTOS/Source/portable/GCC/ARM_CM4F/port.c b/FreeRTOS/Source/portable/GCC/ARM_CM4F/port.c index 54cb9a754..6fc47a045 100644 --- a/FreeRTOS/Source/portable/GCC/ARM_CM4F/port.c +++ b/FreeRTOS/Source/portable/GCC/ARM_CM4F/port.c @@ -152,10 +152,6 @@ debugger. */ #define portTASK_RETURN_ADDRESS prvTaskExitError #endif -/* Each task maintains its own interrupt status in the critical nesting -variable. */ -static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; - /* * Setup the timer to generate the tick interrupts. The implementation in this * file is weak to allow application writers to change the timer used to @@ -187,10 +183,14 @@ static void prvTaskExitError( void ); /*-----------------------------------------------------------*/ +/* Each task maintains its own interrupt status in the critical nesting +variable. */ +static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; + /* * The number of SysTick increments that make up one tick period. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulTimerCountsForOneTick = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -198,7 +198,7 @@ static void prvTaskExitError( void ); * 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 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t xMaximumPossibleSuppressedTicks = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -206,7 +206,7 @@ static void prvTaskExitError( void ); * Compensate for the CPU cycles that pass while the SysTick is stopped (low * power functionality only. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulStoppedTimerCompensation = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -215,7 +215,7 @@ static void prvTaskExitError( void ); * FreeRTOS API functions are not called from interrupts that have been assigned * a priority above configMAX_SYSCALL_INTERRUPT_PRIORITY. */ -#if ( configASSERT_DEFINED == 1 ) +#if( configASSERT_DEFINED == 1 ) static uint8_t ucMaxSysCallPriority = 0; static uint32_t ulMaxPRIGROUPValue = 0; static const volatile uint8_t * const pcInterruptPriorityRegisters = ( const volatile uint8_t * const ) portNVIC_IP_REGISTERS_OFFSET_16; @@ -412,8 +412,11 @@ BaseType_t xPortStartScheduler( void ) /* Should never get here as the tasks will now be executing! Call the task exit error function to prevent compiler warnings about a static function not being called in the case that the application writer overrides this - functionality by defining configTASK_RETURN_ADDRESS. */ + functionality by defining configTASK_RETURN_ADDRESS. Call + vTaskSwitchContext() so link time optimisation does not remove the + symbol. */ prvTaskExitError(); + vTaskSwitchContext(); /* Should not get here! */ return 0; @@ -533,11 +536,11 @@ void xPortSysTickHandler( void ) } /*-----------------------------------------------------------*/ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) __attribute__((weak)) void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime ) { - uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements, ulSysTickCTRL; + uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements; TickType_t xModifiableIdleTime; /* Make sure the SysTick reload value does not overflow the counter. */ @@ -613,23 +616,41 @@ void xPortSysTickHandler( void ) } configPOST_SLEEP_PROCESSING( xExpectedIdleTime ); - /* Stop SysTick. 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. */ - ulSysTickCTRL = portNVIC_SYSTICK_CTRL_REG; - portNVIC_SYSTICK_CTRL_REG = ( ulSysTickCTRL & ~portNVIC_SYSTICK_ENABLE_BIT ); - - /* Re-enable interrupts - see comments above the cpsid instruction() - above. */ + /* 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. */ __asm volatile( "cpsie i" ::: "memory" ); - - if( ( ulSysTickCTRL & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 ) + __asm volatile( "dsb" ); + __asm volatile( "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. */ + __asm volatile( "cpsid i" ::: "memory" ); + __asm volatile( "dsb" ); + __asm volatile( "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 has already executed, and the SysTick - count reloaded with ulReloadValue. Reset the + /* 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 ); @@ -644,11 +665,9 @@ void xPortSysTickHandler( void ) portNVIC_SYSTICK_LOAD_REG = ulCalculatedLoadValue; - /* The tick interrupt handler will already have pended the tick - processing in the kernel. 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. */ + /* 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 @@ -670,17 +689,14 @@ void xPortSysTickHandler( void ) /* Restart SysTick so it runs from portNVIC_SYSTICK_LOAD_REG again, then set portNVIC_SYSTICK_LOAD_REG back to its standard - value. The critical section is used to ensure the tick interrupt - can only execute once in the case that the reload register is near - zero. */ + value. */ portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL; - portENTER_CRITICAL(); - { - portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; - vTaskStepTick( ulCompleteTickPeriods ); - portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; - } - portEXIT_CRITICAL(); + portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; + vTaskStepTick( ulCompleteTickPeriods ); + portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; + + /* Exit with interrpts enabled. */ + __asm volatile( "cpsie i" ::: "memory" ); } } @@ -694,7 +710,7 @@ void xPortSysTickHandler( void ) __attribute__(( weak )) void vPortSetupTimerInterrupt( void ) { /* Calculate the constants required to configure the tick interrupt. */ - #if configUSE_TICKLESS_IDLE == 1 + #if( configUSE_TICKLESS_IDLE == 1 ) { ulTimerCountsForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ); xMaximumPossibleSuppressedTicks = portMAX_24_BIT_NUMBER / ulTimerCountsForOneTick; @@ -781,7 +797,7 @@ static void vPortEnableVFP( void ) devices by calling NVIC_SetPriorityGrouping( 0 ); before starting the scheduler. Note however that some vendor specific peripheral libraries assume a non-zero priority group setting, in which cases using a value - of zero will result in unpredicable behaviour. */ + of zero will result in unpredictable behaviour. */ configASSERT( ( portAIRCR_REG & portPRIORITY_GROUP_MASK ) <= ulMaxPRIGROUPValue ); } diff --git a/FreeRTOS/Source/portable/GCC/ARM_CM7/r0p1/port.c b/FreeRTOS/Source/portable/GCC/ARM_CM7/r0p1/port.c index 132333daa..b80e0d0b3 100644 --- a/FreeRTOS/Source/portable/GCC/ARM_CM7/r0p1/port.c +++ b/FreeRTOS/Source/portable/GCC/ARM_CM7/r0p1/port.c @@ -118,25 +118,25 @@ #define portVECTACTIVE_MASK ( 0xFFUL ) /* Constants required to manipulate the VFP. */ -#define portFPCCR ( ( volatile uint32_t * ) 0xe000ef34 ) /* Floating point context control register. */ -#define portASPEN_AND_LSPEN_BITS ( 0x3UL << 30UL ) +#define portFPCCR ( ( volatile uint32_t * ) 0xe000ef34 ) /* Floating point context control register. */ +#define portASPEN_AND_LSPEN_BITS ( 0x3UL << 30UL ) /* Constants required to set up the initial stack. */ -#define portINITIAL_XPSR ( 0x01000000 ) -#define portINITIAL_EXEC_RETURN ( 0xfffffffd ) +#define portINITIAL_XPSR ( 0x01000000 ) +#define portINITIAL_EXEC_RETURN ( 0xfffffffd ) /* The systick is a 24-bit counter. */ #define portMAX_24_BIT_NUMBER ( 0xffffffUL ) +/* For strict compliance with the Cortex-M spec the task start address should +have bit-0 clear, as it is loaded into the PC on exit from an ISR. */ +#define portSTART_ADDRESS_MASK ( ( StackType_t ) 0xfffffffeUL ) + /* A fiddle factor to estimate the number of SysTick counts that would have occurred while the SysTick counter is stopped during tickless idle calculations. */ #define portMISSED_COUNTS_FACTOR ( 45UL ) -/* For strict compliance with the Cortex-M spec the task start address should -have bit-0 clear, as it is loaded into the PC on exit from an ISR. */ -#define portSTART_ADDRESS_MASK ( ( StackType_t ) 0xfffffffeUL ) - /* Let the user override the pre-loading of the initial LR with the address of prvTaskExitError() in case it messes up unwinding of the stack in the debugger. */ @@ -146,10 +146,6 @@ debugger. */ #define portTASK_RETURN_ADDRESS prvTaskExitError #endif -/* Each task maintains its own interrupt status in the critical nesting -variable. */ -static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; - /* * Setup the timer to generate the tick interrupts. The implementation in this * file is weak to allow application writers to change the timer used to @@ -172,7 +168,7 @@ static void prvPortStartFirstTask( void ) __attribute__ (( naked )); /* * Function to enable the VFP. */ - static void vPortEnableVFP( void ) __attribute__ (( naked )); +static void vPortEnableVFP( void ) __attribute__ (( naked )); /* * Used to catch tasks that attempt to return from their implementing function. @@ -181,10 +177,14 @@ static void prvTaskExitError( void ); /*-----------------------------------------------------------*/ +/* Each task maintains its own interrupt status in the critical nesting +variable. */ +static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; + /* * The number of SysTick increments that make up one tick period. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulTimerCountsForOneTick = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -192,7 +192,7 @@ static void prvTaskExitError( void ); * 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 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t xMaximumPossibleSuppressedTicks = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -200,7 +200,7 @@ static void prvTaskExitError( void ); * Compensate for the CPU cycles that pass while the SysTick is stopped (low * power functionality only. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulStoppedTimerCompensation = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -209,7 +209,7 @@ static void prvTaskExitError( void ); * FreeRTOS API functions are not called from interrupts that have been assigned * a priority above configMAX_SYSCALL_INTERRUPT_PRIORITY. */ -#if ( configASSERT_DEFINED == 1 ) +#if( configASSERT_DEFINED == 1 ) static uint8_t ucMaxSysCallPriority = 0; static uint32_t ulMaxPRIGROUPValue = 0; static const volatile uint8_t * const pcInterruptPriorityRegisters = ( const volatile uint8_t * const ) portNVIC_IP_REGISTERS_OFFSET_16; @@ -400,8 +400,11 @@ BaseType_t xPortStartScheduler( void ) /* Should never get here as the tasks will now be executing! Call the task exit error function to prevent compiler warnings about a static function not being called in the case that the application writer overrides this - functionality by defining configTASK_RETURN_ADDRESS. */ + functionality by defining configTASK_RETURN_ADDRESS. Call + vTaskSwitchContext() so link time optimisation does not remove the + symbol. */ prvTaskExitError(); + vTaskSwitchContext(); /* Should not get here! */ return 0; @@ -523,11 +526,11 @@ void xPortSysTickHandler( void ) } /*-----------------------------------------------------------*/ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) __attribute__((weak)) void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime ) { - uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements, ulSysTickCTRL; + uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements; TickType_t xModifiableIdleTime; /* Make sure the SysTick reload value does not overflow the counter. */ @@ -603,23 +606,41 @@ void xPortSysTickHandler( void ) } configPOST_SLEEP_PROCESSING( xExpectedIdleTime ); - /* Stop SysTick. 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. */ - ulSysTickCTRL = portNVIC_SYSTICK_CTRL_REG; - portNVIC_SYSTICK_CTRL_REG = ( ulSysTickCTRL & ~portNVIC_SYSTICK_ENABLE_BIT ); - - /* Re-enable interrupts - see comments above the cpsid instruction() - above. */ + /* 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. */ __asm volatile( "cpsie i" ::: "memory" ); - - if( ( ulSysTickCTRL & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 ) + __asm volatile( "dsb" ); + __asm volatile( "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. */ + __asm volatile( "cpsid i" ::: "memory" ); + __asm volatile( "dsb" ); + __asm volatile( "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 has already executed, and the SysTick - count reloaded with ulReloadValue. Reset the + /* 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 ); @@ -634,11 +655,9 @@ void xPortSysTickHandler( void ) portNVIC_SYSTICK_LOAD_REG = ulCalculatedLoadValue; - /* The tick interrupt handler will already have pended the tick - processing in the kernel. 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. */ + /* 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 @@ -660,17 +679,14 @@ void xPortSysTickHandler( void ) /* Restart SysTick so it runs from portNVIC_SYSTICK_LOAD_REG again, then set portNVIC_SYSTICK_LOAD_REG back to its standard - value. The critical section is used to ensure the tick interrupt - can only execute once in the case that the reload register is near - zero. */ + value. */ portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL; - portENTER_CRITICAL(); - { - portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; - vTaskStepTick( ulCompleteTickPeriods ); - portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; - } - portEXIT_CRITICAL(); + portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; + vTaskStepTick( ulCompleteTickPeriods ); + portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; + + /* Exit with interrpts enabled. */ + __asm volatile( "cpsie i" ::: "memory" ); } } @@ -684,7 +700,7 @@ void xPortSysTickHandler( void ) __attribute__(( weak )) void vPortSetupTimerInterrupt( void ) { /* Calculate the constants required to configure the tick interrupt. */ - #if configUSE_TICKLESS_IDLE == 1 + #if( configUSE_TICKLESS_IDLE == 1 ) { ulTimerCountsForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ); xMaximumPossibleSuppressedTicks = portMAX_24_BIT_NUMBER / ulTimerCountsForOneTick; @@ -771,7 +787,7 @@ static void vPortEnableVFP( void ) devices by calling NVIC_SetPriorityGrouping( 0 ); before starting the scheduler. Note however that some vendor specific peripheral libraries assume a non-zero priority group setting, in which cases using a value - of zero will result in unpredicable behaviour. */ + of zero will result in unpredictable behaviour. */ configASSERT( ( portAIRCR_REG & portPRIORITY_GROUP_MASK ) <= ulMaxPRIGROUPValue ); } diff --git a/FreeRTOS/Source/portable/IAR/ARM_CM3/port.c b/FreeRTOS/Source/portable/IAR/ARM_CM3/port.c index d8a10ae1a..272706596 100644 --- a/FreeRTOS/Source/portable/IAR/ARM_CM3/port.c +++ b/FreeRTOS/Source/portable/IAR/ARM_CM3/port.c @@ -78,7 +78,7 @@ #include "FreeRTOS.h" #include "task.h" -#if configMAX_SYSCALL_INTERRUPT_PRIORITY == 0 +#if( configMAX_SYSCALL_INTERRUPT_PRIORITY == 0 ) #error configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to 0. See http://www.FreeRTOS.org/RTOS-Cortex-M3-M4.html #endif @@ -142,10 +142,6 @@ FreeRTOS.org versions prior to V4.3.0 did not include this definition. */ #define configKERNEL_INTERRUPT_PRIORITY 255 #endif -/* Each task maintains its own interrupt status in the critical nesting -variable. */ -static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; - /* * Setup the timer to generate the tick interrupts. The implementation in this * file is weak to allow application writers to change the timer used to @@ -170,10 +166,14 @@ static void prvTaskExitError( void ); /*-----------------------------------------------------------*/ +/* Each task maintains its own interrupt status in the critical nesting +variable. */ +static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; + /* * The number of SysTick increments that make up one tick period. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulTimerCountsForOneTick = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -181,7 +181,7 @@ static void prvTaskExitError( void ); * 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 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t xMaximumPossibleSuppressedTicks = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -189,7 +189,7 @@ static void prvTaskExitError( void ); * Compensate for the CPU cycles that pass while the SysTick is stopped (low * power functionality only. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulStoppedTimerCompensation = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -198,7 +198,7 @@ static void prvTaskExitError( void ); * FreeRTOS API functions are not called from interrupts that have been assigned * a priority above configMAX_SYSCALL_INTERRUPT_PRIORITY. */ -#if ( configASSERT_DEFINED == 1 ) +#if( configASSERT_DEFINED == 1 ) static uint8_t ucMaxSysCallPriority = 0; static uint32_t ulMaxPRIGROUPValue = 0; static const volatile uint8_t * const pcInterruptPriorityRegisters = ( const volatile uint8_t * const ) portNVIC_IP_REGISTERS_OFFSET_16; @@ -246,6 +246,10 @@ static void prvTaskExitError( void ) */ BaseType_t xPortStartScheduler( void ) { + /* configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to 0. + See http://www.FreeRTOS.org/RTOS-Cortex-M3-M4.html */ + configASSERT( configMAX_SYSCALL_INTERRUPT_PRIORITY ); + #if( configASSERT_DEFINED == 1 ) { volatile uint32_t ulOriginalPriority; @@ -383,11 +387,11 @@ void xPortSysTickHandler( void ) } /*-----------------------------------------------------------*/ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) __weak void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime ) { - uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements, ulSysTickCTRL; + uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements; TickType_t xModifiableIdleTime; /* Make sure the SysTick reload value does not overflow the counter. */ @@ -417,7 +421,6 @@ void xPortSysTickHandler( void ) __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 ) @@ -464,23 +467,41 @@ void xPortSysTickHandler( void ) } configPOST_SLEEP_PROCESSING( xExpectedIdleTime ); - /* Stop SysTick. 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. */ - ulSysTickCTRL = portNVIC_SYSTICK_CTRL_REG; - portNVIC_SYSTICK_CTRL_REG = ( ulSysTickCTRL & ~portNVIC_SYSTICK_ENABLE_BIT ); - - /* Re-enable interrupts - see comments above __disable_interrupt() - call above. */ + /* 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(); - - if( ( ulSysTickCTRL & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 ) + __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 has already executed, and the SysTick - count reloaded with ulReloadValue. Reset the + /* 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 ); @@ -495,11 +516,9 @@ void xPortSysTickHandler( void ) portNVIC_SYSTICK_LOAD_REG = ulCalculatedLoadValue; - /* The tick interrupt handler will already have pended the tick - processing in the kernel. 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. */ + /* 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 @@ -521,21 +540,18 @@ void xPortSysTickHandler( void ) /* Restart SysTick so it runs from portNVIC_SYSTICK_LOAD_REG again, then set portNVIC_SYSTICK_LOAD_REG back to its standard - value. The critical section is used to ensure the tick interrupt - can only execute once in the case that the reload register is near - zero. */ + value. */ portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL; - portENTER_CRITICAL(); - { - portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; - vTaskStepTick( ulCompleteTickPeriods ); - portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; - } - portEXIT_CRITICAL(); + portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; + vTaskStepTick( ulCompleteTickPeriods ); + portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; + + /* Exit with interrpts enabled. */ + __enable_interrupt(); } } -#endif /* #if configUSE_TICKLESS_IDLE */ +#endif /* configUSE_TICKLESS_IDLE */ /*-----------------------------------------------------------*/ /* @@ -571,7 +587,7 @@ __weak void vPortSetupTimerInterrupt( void ) uint8_t ucCurrentPriority; /* Obtain the number of the currently executing interrupt. */ - __asm volatile( "mrs %0, ipsr" : "=r"( ulCurrentInterrupt ) ); + __asm volatile( "mrs %0, ipsr" : "=r"( ulCurrentInterrupt ) :: "memory" ); /* Is the interrupt number a user defined interrupt? */ if( ulCurrentInterrupt >= portFIRST_USER_INTERRUPT_NUMBER ) @@ -617,7 +633,7 @@ __weak void vPortSetupTimerInterrupt( void ) devices by calling NVIC_SetPriorityGrouping( 0 ); before starting the scheduler. Note however that some vendor specific peripheral libraries assume a non-zero priority group setting, in which cases using a value - of zero will result in unpredicable behaviour. */ + of zero will result in unpredictable behaviour. */ configASSERT( ( portAIRCR_REG & portPRIORITY_GROUP_MASK ) <= ulMaxPRIGROUPValue ); } diff --git a/FreeRTOS/Source/portable/IAR/ARM_CM3/portmacro.h b/FreeRTOS/Source/portable/IAR/ARM_CM3/portmacro.h index 7b96b771e..e2c3b2f62 100644 --- a/FreeRTOS/Source/portable/IAR/ARM_CM3/portmacro.h +++ b/FreeRTOS/Source/portable/IAR/ARM_CM3/portmacro.h @@ -85,6 +85,9 @@ extern "C" { *----------------------------------------------------------- */ +/* IAR includes. */ +#include + /* Type definitions. */ #define portCHAR char #define portFLOAT float @@ -138,7 +141,7 @@ typedef unsigned long UBaseType_t; #define configUSE_PORT_OPTIMISED_TASK_SELECTION 1 #endif -#if configUSE_PORT_OPTIMISED_TASK_SELECTION == 1 +#if( configUSE_PORT_OPTIMISED_TASK_SELECTION == 1 ) /* Check the configuration. */ #if( configMAX_PRIORITIES > 32 ) @@ -151,7 +154,6 @@ typedef unsigned long UBaseType_t; /*-----------------------------------------------------------*/ - #include #define portGET_HIGHEST_PRIORITY( uxTopPriority, uxReadyPriorities ) uxTopPriority = ( 31UL - ( ( uint32_t ) __CLZ( ( uxReadyPriorities ) ) ) ) #endif /* configUSE_PORT_OPTIMISED_TASK_SELECTION */ diff --git a/FreeRTOS/Source/portable/IAR/ARM_CM4F/port.c b/FreeRTOS/Source/portable/IAR/ARM_CM4F/port.c index 18854f5b3..cd773cffc 100644 --- a/FreeRTOS/Source/portable/IAR/ARM_CM4F/port.c +++ b/FreeRTOS/Source/portable/IAR/ARM_CM4F/port.c @@ -71,7 +71,7 @@ * Implementation of functions defined in portable.h for the ARM CM4F port. *----------------------------------------------------------*/ -/* Compiler includes. */ +/* IAR includes. */ #include /* Scheduler includes. */ @@ -82,7 +82,7 @@ #error This port can only be used when the project options are configured to enable hardware floating point support. #endif -#if configMAX_SYSCALL_INTERRUPT_PRIORITY == 0 +#if( configMAX_SYSCALL_INTERRUPT_PRIORITY == 0 ) #error configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to 0. See http://www.FreeRTOS.org/RTOS-Cortex-M3-M4.html #endif @@ -150,10 +150,6 @@ calculations. */ have bit-0 clear, as it is loaded into the PC on exit from an ISR. */ #define portSTART_ADDRESS_MASK ( ( StackType_t ) 0xfffffffeUL ) -/* Each task maintains its own interrupt status in the critical nesting -variable. */ -static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; - /* * Setup the timer to generate the tick interrupts. The implementation in this * file is weak to allow application writers to change the timer used to @@ -183,10 +179,14 @@ static void prvTaskExitError( void ); /*-----------------------------------------------------------*/ +/* Each task maintains its own interrupt status in the critical nesting +variable. */ +static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; + /* * The number of SysTick increments that make up one tick period. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulTimerCountsForOneTick = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -194,7 +194,7 @@ static void prvTaskExitError( void ); * 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 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t xMaximumPossibleSuppressedTicks = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -202,7 +202,7 @@ static void prvTaskExitError( void ); * Compensate for the CPU cycles that pass while the SysTick is stopped (low * power functionality only. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulStoppedTimerCompensation = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -211,7 +211,7 @@ static void prvTaskExitError( void ); * FreeRTOS API functions are not called from interrupts that have been assigned * a priority above configMAX_SYSCALL_INTERRUPT_PRIORITY. */ -#if ( configASSERT_DEFINED == 1 ) +#if( configASSERT_DEFINED == 1 ) static uint8_t ucMaxSysCallPriority = 0; static uint32_t ulMaxPRIGROUPValue = 0; static const volatile uint8_t * const pcInterruptPriorityRegisters = ( const volatile uint8_t * const ) portNVIC_IP_REGISTERS_OFFSET_16; @@ -424,11 +424,11 @@ void xPortSysTickHandler( void ) } /*-----------------------------------------------------------*/ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) __weak void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime ) { - uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements, ulSysTickCTRL; + uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements; TickType_t xModifiableIdleTime; /* Make sure the SysTick reload value does not overflow the counter. */ @@ -458,7 +458,6 @@ void xPortSysTickHandler( void ) __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 ) @@ -505,23 +504,41 @@ void xPortSysTickHandler( void ) } configPOST_SLEEP_PROCESSING( xExpectedIdleTime ); - /* Stop SysTick. 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. */ - ulSysTickCTRL = portNVIC_SYSTICK_CTRL_REG; - portNVIC_SYSTICK_CTRL_REG = ( ulSysTickCTRL & ~portNVIC_SYSTICK_ENABLE_BIT ); - - /* Re-enable interrupts - see comments above __disable_interrupt() - call above. */ + /* 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(); - - if( ( ulSysTickCTRL & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 ) + __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 has already executed, and the SysTick - count reloaded with ulReloadValue. Reset the + /* 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 ); @@ -536,11 +553,9 @@ void xPortSysTickHandler( void ) portNVIC_SYSTICK_LOAD_REG = ulCalculatedLoadValue; - /* The tick interrupt handler will already have pended the tick - processing in the kernel. 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. */ + /* 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 @@ -562,21 +577,18 @@ void xPortSysTickHandler( void ) /* Restart SysTick so it runs from portNVIC_SYSTICK_LOAD_REG again, then set portNVIC_SYSTICK_LOAD_REG back to its standard - value. The critical section is used to ensure the tick interrupt - can only execute once in the case that the reload register is near - zero. */ + value. */ portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL; - portENTER_CRITICAL(); - { - portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; - vTaskStepTick( ulCompleteTickPeriods ); - portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; - } - portEXIT_CRITICAL(); + portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; + vTaskStepTick( ulCompleteTickPeriods ); + portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; + + /* Exit with interrpts enabled. */ + __enable_interrupt(); } } -#endif /* #if configUSE_TICKLESS_IDLE */ +#endif /* configUSE_TICKLESS_IDLE */ /*-----------------------------------------------------------*/ /* @@ -612,7 +624,7 @@ __weak void vPortSetupTimerInterrupt( void ) uint8_t ucCurrentPriority; /* Obtain the number of the currently executing interrupt. */ - __asm volatile( "mrs %0, ipsr" : "=r"( ulCurrentInterrupt ) ); + __asm volatile( "mrs %0, ipsr" : "=r"( ulCurrentInterrupt ) :: "memory" ); /* Is the interrupt number a user defined interrupt? */ if( ulCurrentInterrupt >= portFIRST_USER_INTERRUPT_NUMBER ) @@ -658,7 +670,7 @@ __weak void vPortSetupTimerInterrupt( void ) devices by calling NVIC_SetPriorityGrouping( 0 ); before starting the scheduler. Note however that some vendor specific peripheral libraries assume a non-zero priority group setting, in which cases using a value - of zero will result in unpredicable behaviour. */ + of zero will result in unpredictable behaviour. */ configASSERT( ( portAIRCR_REG & portPRIORITY_GROUP_MASK ) <= ulMaxPRIGROUPValue ); } diff --git a/FreeRTOS/Source/portable/IAR/ARM_CM4F/portmacro.h b/FreeRTOS/Source/portable/IAR/ARM_CM4F/portmacro.h index 007dcfaca..a14a7cd20 100644 --- a/FreeRTOS/Source/portable/IAR/ARM_CM4F/portmacro.h +++ b/FreeRTOS/Source/portable/IAR/ARM_CM4F/portmacro.h @@ -84,6 +84,9 @@ extern "C" { *----------------------------------------------------------- */ +/* IAR includes. */ +#include + /* Type definitions. */ #define portCHAR char #define portFLOAT float @@ -137,7 +140,7 @@ typedef unsigned long UBaseType_t; #define configUSE_PORT_OPTIMISED_TASK_SELECTION 1 #endif -#if configUSE_PORT_OPTIMISED_TASK_SELECTION == 1 +#if( configUSE_PORT_OPTIMISED_TASK_SELECTION == 1 ) /* Check the configuration. */ #if( configMAX_PRIORITIES > 32 ) @@ -150,7 +153,6 @@ typedef unsigned long UBaseType_t; /*-----------------------------------------------------------*/ - #include #define portGET_HIGHEST_PRIORITY( uxTopPriority, uxReadyPriorities ) uxTopPriority = ( 31UL - ( ( uint32_t ) __CLZ( ( uxReadyPriorities ) ) ) ) #endif /* configUSE_PORT_OPTIMISED_TASK_SELECTION */ diff --git a/FreeRTOS/Source/portable/IAR/ARM_CM7/r0p1/port.c b/FreeRTOS/Source/portable/IAR/ARM_CM7/r0p1/port.c index f5a30bc63..7ec4084df 100644 --- a/FreeRTOS/Source/portable/IAR/ARM_CM7/r0p1/port.c +++ b/FreeRTOS/Source/portable/IAR/ARM_CM7/r0p1/port.c @@ -71,7 +71,7 @@ * Implementation of functions defined in portable.h for the ARM CM4F port. *----------------------------------------------------------*/ -/* Compiler includes. */ +/* IAR includes. */ #include /* Scheduler includes. */ @@ -82,7 +82,7 @@ #error This port can only be used when the project options are configured to enable hardware floating point support. #endif -#if configMAX_SYSCALL_INTERRUPT_PRIORITY == 0 +#if( configMAX_SYSCALL_INTERRUPT_PRIORITY == 0 ) #error configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to 0. See http://www.FreeRTOS.org/RTOS-Cortex-M3-M4.html #endif @@ -144,10 +144,6 @@ calculations. */ have bit-0 clear, as it is loaded into the PC on exit from an ISR. */ #define portSTART_ADDRESS_MASK ( ( StackType_t ) 0xfffffffeUL ) -/* Each task maintains its own interrupt status in the critical nesting -variable. */ -static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; - /* * Setup the timer to generate the tick interrupts. The implementation in this * file is weak to allow application writers to change the timer used to @@ -177,10 +173,14 @@ static void prvTaskExitError( void ); /*-----------------------------------------------------------*/ +/* Each task maintains its own interrupt status in the critical nesting +variable. */ +static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; + /* * The number of SysTick increments that make up one tick period. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulTimerCountsForOneTick = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -188,7 +188,7 @@ static void prvTaskExitError( void ); * 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 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t xMaximumPossibleSuppressedTicks = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -196,7 +196,7 @@ static void prvTaskExitError( void ); * Compensate for the CPU cycles that pass while the SysTick is stopped (low * power functionality only. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulStoppedTimerCompensation = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -205,7 +205,7 @@ static void prvTaskExitError( void ); * FreeRTOS API functions are not called from interrupts that have been assigned * a priority above configMAX_SYSCALL_INTERRUPT_PRIORITY. */ -#if ( configASSERT_DEFINED == 1 ) +#if( configASSERT_DEFINED == 1 ) static uint8_t ucMaxSysCallPriority = 0; static uint32_t ulMaxPRIGROUPValue = 0; static const volatile uint8_t * const pcInterruptPriorityRegisters = ( const volatile uint8_t * const ) portNVIC_IP_REGISTERS_OFFSET_16; @@ -265,6 +265,10 @@ static void prvTaskExitError( void ) */ BaseType_t xPortStartScheduler( void ) { + /* configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to 0. + See http://www.FreeRTOS.org/RTOS-Cortex-M3-M4.html */ + configASSERT( configMAX_SYSCALL_INTERRUPT_PRIORITY ); + #if( configASSERT_DEFINED == 1 ) { volatile uint32_t ulOriginalPriority; @@ -408,11 +412,11 @@ void xPortSysTickHandler( void ) } /*-----------------------------------------------------------*/ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) __weak void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime ) { - uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements, ulSysTickCTRL; + uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements; TickType_t xModifiableIdleTime; /* Make sure the SysTick reload value does not overflow the counter. */ @@ -488,23 +492,41 @@ void xPortSysTickHandler( void ) } configPOST_SLEEP_PROCESSING( xExpectedIdleTime ); - /* Stop SysTick. 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. */ - ulSysTickCTRL = portNVIC_SYSTICK_CTRL_REG; - portNVIC_SYSTICK_CTRL_REG = ( ulSysTickCTRL & ~portNVIC_SYSTICK_ENABLE_BIT ); - - /* Re-enable interrupts - see comments above __disable_interrupt() - call above. */ + /* 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(); - - if( ( ulSysTickCTRL & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 ) + __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 has already executed, and the SysTick - count reloaded with ulReloadValue. Reset the + /* 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 ); @@ -519,11 +541,9 @@ void xPortSysTickHandler( void ) portNVIC_SYSTICK_LOAD_REG = ulCalculatedLoadValue; - /* The tick interrupt handler will already have pended the tick - processing in the kernel. 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. */ + /* 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 @@ -545,21 +565,18 @@ void xPortSysTickHandler( void ) /* Restart SysTick so it runs from portNVIC_SYSTICK_LOAD_REG again, then set portNVIC_SYSTICK_LOAD_REG back to its standard - value. The critical section is used to ensure the tick interrupt - can only execute once in the case that the reload register is near - zero. */ + value. */ portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL; - portENTER_CRITICAL(); - { - portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; - vTaskStepTick( ulCompleteTickPeriods ); - portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; - } - portEXIT_CRITICAL(); + portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; + vTaskStepTick( ulCompleteTickPeriods ); + portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; + + /* Exit with interrpts enabled. */ + __enable_interrupt(); } } -#endif /* #if configUSE_TICKLESS_IDLE */ +#endif /* configUSE_TICKLESS_IDLE */ /*-----------------------------------------------------------*/ /* @@ -595,7 +612,7 @@ __weak void vPortSetupTimerInterrupt( void ) uint8_t ucCurrentPriority; /* Obtain the number of the currently executing interrupt. */ - __asm volatile( "mrs %0, ipsr" : "=r"( ulCurrentInterrupt ) ); + __asm volatile( "mrs %0, ipsr" : "=r"( ulCurrentInterrupt ) :: "memory" ); /* Is the interrupt number a user defined interrupt? */ if( ulCurrentInterrupt >= portFIRST_USER_INTERRUPT_NUMBER ) @@ -641,7 +658,7 @@ __weak void vPortSetupTimerInterrupt( void ) devices by calling NVIC_SetPriorityGrouping( 0 ); before starting the scheduler. Note however that some vendor specific peripheral libraries assume a non-zero priority group setting, in which cases using a value - of zero will result in unpredicable behaviour. */ + of zero will result in unpredictable behaviour. */ configASSERT( ( portAIRCR_REG & portPRIORITY_GROUP_MASK ) <= ulMaxPRIGROUPValue ); } diff --git a/FreeRTOS/Source/portable/IAR/ARM_CM7/r0p1/portmacro.h b/FreeRTOS/Source/portable/IAR/ARM_CM7/r0p1/portmacro.h index a1534cd8f..bf8d19845 100644 --- a/FreeRTOS/Source/portable/IAR/ARM_CM7/r0p1/portmacro.h +++ b/FreeRTOS/Source/portable/IAR/ARM_CM7/r0p1/portmacro.h @@ -84,6 +84,9 @@ extern "C" { *----------------------------------------------------------- */ +/* IAR includes. */ +#include + /* Type definitions. */ #define portCHAR char #define portFLOAT float @@ -137,7 +140,7 @@ typedef unsigned long UBaseType_t; #define configUSE_PORT_OPTIMISED_TASK_SELECTION 1 #endif -#if configUSE_PORT_OPTIMISED_TASK_SELECTION == 1 +#if( configUSE_PORT_OPTIMISED_TASK_SELECTION == 1 ) /* Check the configuration. */ #if( configMAX_PRIORITIES > 32 ) @@ -150,7 +153,6 @@ typedef unsigned long UBaseType_t; /*-----------------------------------------------------------*/ - #include #define portGET_HIGHEST_PRIORITY( uxTopPriority, uxReadyPriorities ) uxTopPriority = ( 31UL - ( ( uint32_t ) __CLZ( ( uxReadyPriorities ) ) ) ) #endif /* configUSE_PORT_OPTIMISED_TASK_SELECTION */ diff --git a/FreeRTOS/Source/portable/MikroC/ARM_CM4F/port.c b/FreeRTOS/Source/portable/MikroC/ARM_CM4F/port.c index 3345a5d3d..761806d21 100644 --- a/FreeRTOS/Source/portable/MikroC/ARM_CM4F/port.c +++ b/FreeRTOS/Source/portable/MikroC/ARM_CM4F/port.c @@ -196,7 +196,7 @@ static void prvTaskExitError( void ); /* * The number of SysTick increments that make up one tick period. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulTimerCountsForOneTick = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -204,7 +204,7 @@ static void prvTaskExitError( void ); * 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 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t xMaximumPossibleSuppressedTicks = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -212,7 +212,7 @@ static void prvTaskExitError( void ); * Compensate for the CPU cycles that pass while the SysTick is stopped (low * power functionality only. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulStoppedTimerCompensation = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -535,7 +535,7 @@ void xPortSysTickHandler( void ) iv IVT_INT_SysTick ics ICS_AUTO void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime ) { - uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements, ulSysTickCTRL; + uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements; TickType_t xModifiableIdleTime; /* Make sure the SysTick reload value does not overflow the counter. */ @@ -611,25 +611,41 @@ void xPortSysTickHandler( void ) iv IVT_INT_SysTick ics ICS_AUTO } configPOST_SLEEP_PROCESSING( xExpectedIdleTime ); - /* Stop SysTick. 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. */ - ulSysTickCTRL = portNVIC_SYSTICK_CTRL_REG; - portNVIC_SYSTICK_CTRL_REG = ( ulSysTickCTRL & ~portNVIC_SYSTICK_ENABLE_BIT ); - - /* Re-enable interrupts - see comments above the cpsid instruction() - above. */ + /* 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. */ __asm { "cpsie i" }; - __asm { "wfi" }; - __asm { "isb" }; - - if( ( ulSysTickCTRL & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 ) + __asm { "dsb" }; + __asm { "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. */ + __asm { "cpsid i" }; + __asm { "dsb" }; + __asm { "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 has already executed, and the SysTick - count reloaded with ulReloadValue. Reset the + /* 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 ); @@ -644,11 +660,9 @@ void xPortSysTickHandler( void ) iv IVT_INT_SysTick ics ICS_AUTO portNVIC_SYSTICK_LOAD_REG = ulCalculatedLoadValue; - /* The tick interrupt handler will already have pended the tick - processing in the kernel. 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. */ + /* 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 @@ -665,22 +679,19 @@ void xPortSysTickHandler( void ) iv IVT_INT_SysTick ics ICS_AUTO /* The reload value is set to whatever fraction of a single tick period remains. */ - portNVIC_SYSTICK_LOAD_REG = ( ( ulCompleteTickPeriods + 1 ) * ulTimerCountsForOneTick ) - ulCompletedSysTickDecrements; + 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. The critical section is used to ensure the tick interrupt - can only execute once in the case that the reload register is near - zero. */ + value. */ portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL; - portENTER_CRITICAL(); - { - portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; - vTaskStepTick( ulCompleteTickPeriods ); - portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; - } - portEXIT_CRITICAL(); + portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; + vTaskStepTick( ulCompleteTickPeriods ); + portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; + + /* Exit with interrpts enabled. */ + __asm { "cpsie i" }; } } @@ -696,7 +707,7 @@ void xPortSysTickHandler( void ) iv IVT_INT_SysTick ics ICS_AUTO void vPortSetupTimerInterrupt( void ) { /* Calculate the constants required to configure the tick interrupt. */ - #if configUSE_TICKLESS_IDLE == 1 + #if( configUSE_TICKLESS_IDLE == 1 ) { ulTimerCountsForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ); xMaximumPossibleSuppressedTicks = portMAX_24_BIT_NUMBER / ulTimerCountsForOneTick; @@ -812,7 +823,7 @@ BaseType_t xReturn; devices by calling NVIC_SetPriorityGrouping( 0 ); before starting the scheduler. Note however that some vendor specific peripheral libraries assume a non-zero priority group setting, in which cases using a value - of zero will result in unpredicable behaviour. */ + of zero will result in unpredictable behaviour. */ configASSERT( ( portAIRCR_REG & portPRIORITY_GROUP_MASK ) <= ulMaxPRIGROUPValue ); } diff --git a/FreeRTOS/Source/portable/RVDS/ARM_CM3/port.c b/FreeRTOS/Source/portable/RVDS/ARM_CM3/port.c index 6956b1a46..5fd109146 100644 --- a/FreeRTOS/Source/portable/RVDS/ARM_CM3/port.c +++ b/FreeRTOS/Source/portable/RVDS/ARM_CM3/port.c @@ -114,9 +114,6 @@ is defined. */ #define portNVIC_PENDSVCLEAR_BIT ( 1UL << 27UL ) #define portNVIC_PEND_SYSTICK_CLEAR_BIT ( 1UL << 25UL ) -/* Masks off all bits but the VECTACTIVE bits in the ICSR register. */ -#define portVECTACTIVE_MASK ( 0xFFUL ) - #define portNVIC_PENDSV_PRI ( ( ( uint32_t ) configKERNEL_INTERRUPT_PRIORITY ) << 16UL ) #define portNVIC_SYSTICK_PRI ( ( ( uint32_t ) configKERNEL_INTERRUPT_PRIORITY ) << 24UL ) @@ -130,6 +127,9 @@ is defined. */ #define portPRIORITY_GROUP_MASK ( 0x07UL << 8UL ) #define portPRIGROUP_SHIFT ( 8UL ) +/* Masks off all bits but the VECTACTIVE bits in the ICSR register. */ +#define portVECTACTIVE_MASK ( 0xFFUL ) + /* Constants required to set up the initial stack. */ #define portINITIAL_XPSR ( 0x01000000 ) @@ -145,10 +145,6 @@ calculations. */ have bit-0 clear, as it is loaded into the PC on exit from an ISR. */ #define portSTART_ADDRESS_MASK ( ( StackType_t ) 0xfffffffeUL ) -/* Each task maintains its own interrupt status in the critical nesting -variable. */ -static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; - /* * Setup the timer to generate the tick interrupts. The implementation in this * file is weak to allow application writers to change the timer used to @@ -175,10 +171,14 @@ static void prvTaskExitError( void ); /*-----------------------------------------------------------*/ +/* Each task maintains its own interrupt status in the critical nesting +variable. */ +static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; + /* * The number of SysTick increments that make up one tick period. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulTimerCountsForOneTick = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -186,7 +186,7 @@ static void prvTaskExitError( void ); * 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 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t xMaximumPossibleSuppressedTicks = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -194,7 +194,7 @@ static void prvTaskExitError( void ); * Compensate for the CPU cycles that pass while the SysTick is stopped (low * power functionality only. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulStoppedTimerCompensation = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -313,6 +313,10 @@ BaseType_t xPortStartScheduler( void ) /* Read the value back to see how many bits stuck. */ ucMaxPriorityValue = *pucFirstUserPriorityRegister; + /* The kernel interrupt priority should be set to the lowest + priority. */ + configASSERT( ucMaxPriorityValue == ( configKERNEL_INTERRUPT_PRIORITY & ucMaxPriorityValue ) ); + /* Use the same mask on the maximum system call priority. */ ucMaxSysCallPriority = configMAX_SYSCALL_INTERRUPT_PRIORITY & ucMaxPriorityValue; @@ -467,11 +471,11 @@ void xPortSysTickHandler( void ) } /*-----------------------------------------------------------*/ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) __weak void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime ) { - uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements, ulSysTickCTRL; + uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements; TickType_t xModifiableIdleTime; /* Make sure the SysTick reload value does not overflow the counter. */ @@ -547,23 +551,41 @@ void xPortSysTickHandler( void ) } configPOST_SLEEP_PROCESSING( xExpectedIdleTime ); - /* Stop SysTick. 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. */ - ulSysTickCTRL = portNVIC_SYSTICK_CTRL_REG; - portNVIC_SYSTICK_CTRL_REG = ( ulSysTickCTRL & ~portNVIC_SYSTICK_ENABLE_BIT ); - - /* Re-enable interrupts - see comments above __disable_irq() call - above. */ + /* 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(); - - if( ( ulSysTickCTRL & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 ) + __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 has already executed, and the SysTick - count reloaded with ulReloadValue. Reset the + /* 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 ); @@ -578,11 +600,9 @@ void xPortSysTickHandler( void ) portNVIC_SYSTICK_LOAD_REG = ulCalculatedLoadValue; - /* The tick interrupt handler will already have pended the tick - processing in the kernel. 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. */ + /* 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 @@ -604,17 +624,14 @@ void xPortSysTickHandler( void ) /* Restart SysTick so it runs from portNVIC_SYSTICK_LOAD_REG again, then set portNVIC_SYSTICK_LOAD_REG back to its standard - value. The critical section is used to ensure the tick interrupt - can only execute once in the case that the reload register is near - zero. */ + value. */ portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL; - portENTER_CRITICAL(); - { - portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; - vTaskStepTick( ulCompleteTickPeriods ); - portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; - } - portEXIT_CRITICAL(); + portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; + vTaskStepTick( ulCompleteTickPeriods ); + portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; + + /* Exit with interrpts enabled. */ + __enable_irq(); } } @@ -626,12 +643,12 @@ void xPortSysTickHandler( void ) * Setup the SysTick timer to generate the tick interrupts at the required * frequency. */ -#if configOVERRIDE_DEFAULT_TICK_CONFIGURATION == 0 +#if( configOVERRIDE_DEFAULT_TICK_CONFIGURATION == 0 ) void vPortSetupTimerInterrupt( void ) { /* Calculate the constants required to configure the tick interrupt. */ - #if configUSE_TICKLESS_IDLE == 1 + #if( configUSE_TICKLESS_IDLE == 1 ) { ulTimerCountsForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ); xMaximumPossibleSuppressedTicks = portMAX_24_BIT_NUMBER / ulTimerCountsForOneTick; @@ -714,7 +731,7 @@ __asm uint32_t vPortGetIPSR( void ) devices by calling NVIC_SetPriorityGrouping( 0 ); before starting the scheduler. Note however that some vendor specific peripheral libraries assume a non-zero priority group setting, in which cases using a value - of zero will result in unpredicable behaviour. */ + of zero will result in unpredictable behaviour. */ configASSERT( ( portAIRCR_REG & portPRIORITY_GROUP_MASK ) <= ulMaxPRIGROUPValue ); } diff --git a/FreeRTOS/Source/portable/RVDS/ARM_CM4F/port.c b/FreeRTOS/Source/portable/RVDS/ARM_CM4F/port.c index 9086cc9a6..5d33ef8f5 100644 --- a/FreeRTOS/Source/portable/RVDS/ARM_CM4F/port.c +++ b/FreeRTOS/Source/portable/RVDS/ARM_CM4F/port.c @@ -156,10 +156,6 @@ calculations. */ have bit-0 clear, as it is loaded into the PC on exit from an ISR. */ #define portSTART_ADDRESS_MASK ( ( StackType_t ) 0xfffffffeUL ) -/* Each task maintains its own interrupt status in the critical nesting -variable. */ -static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; - /* * Setup the timer to generate the tick interrupts. The implementation in this * file is weak to allow application writers to change the timer used to @@ -191,10 +187,14 @@ static void prvTaskExitError( void ); /*-----------------------------------------------------------*/ +/* Each task maintains its own interrupt status in the critical nesting +variable. */ +static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; + /* * The number of SysTick increments that make up one tick period. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulTimerCountsForOneTick = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -202,7 +202,7 @@ static void prvTaskExitError( void ); * 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 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t xMaximumPossibleSuppressedTicks = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -210,7 +210,7 @@ static void prvTaskExitError( void ); * Compensate for the CPU cycles that pass while the SysTick is stopped (low * power functionality only. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulStoppedTimerCompensation = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -561,11 +561,11 @@ void xPortSysTickHandler( void ) } /*-----------------------------------------------------------*/ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) __weak void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime ) { - uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements, ulSysTickCTRL; + uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements; TickType_t xModifiableIdleTime; /* Make sure the SysTick reload value does not overflow the counter. */ @@ -641,23 +641,41 @@ void xPortSysTickHandler( void ) } configPOST_SLEEP_PROCESSING( xExpectedIdleTime ); - /* Stop SysTick. 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. */ - ulSysTickCTRL = portNVIC_SYSTICK_CTRL_REG; - portNVIC_SYSTICK_CTRL_REG = ( ulSysTickCTRL & ~portNVIC_SYSTICK_ENABLE_BIT ); - - /* Re-enable interrupts - see comments above __disable_irq() call - above. */ + /* 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(); - - if( ( ulSysTickCTRL & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 ) + __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 has already executed, and the SysTick - count reloaded with ulReloadValue. Reset the + /* 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 ); @@ -672,11 +690,9 @@ void xPortSysTickHandler( void ) portNVIC_SYSTICK_LOAD_REG = ulCalculatedLoadValue; - /* The tick interrupt handler will already have pended the tick - processing in the kernel. 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. */ + /* 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 @@ -698,17 +714,14 @@ void xPortSysTickHandler( void ) /* Restart SysTick so it runs from portNVIC_SYSTICK_LOAD_REG again, then set portNVIC_SYSTICK_LOAD_REG back to its standard - value. The critical section is used to ensure the tick interrupt - can only execute once in the case that the reload register is near - zero. */ + value. */ portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL; - portENTER_CRITICAL(); - { - portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; - vTaskStepTick( ulCompleteTickPeriods ); - portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; - } - portEXIT_CRITICAL(); + portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; + vTaskStepTick( ulCompleteTickPeriods ); + portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; + + /* Exit with interrpts enabled. */ + __enable_irq(); } } @@ -725,7 +738,7 @@ void xPortSysTickHandler( void ) void vPortSetupTimerInterrupt( void ) { /* Calculate the constants required to configure the tick interrupt. */ - #if configUSE_TICKLESS_IDLE == 1 + #if( configUSE_TICKLESS_IDLE == 1 ) { ulTimerCountsForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ); xMaximumPossibleSuppressedTicks = portMAX_24_BIT_NUMBER / ulTimerCountsForOneTick; @@ -808,7 +821,7 @@ __asm uint32_t vPortGetIPSR( void ) devices by calling NVIC_SetPriorityGrouping( 0 ); before starting the scheduler. Note however that some vendor specific peripheral libraries assume a non-zero priority group setting, in which cases using a value - of zero will result in unpredicable behaviour. */ + of zero will result in unpredictable behaviour. */ configASSERT( ( portAIRCR_REG & portPRIORITY_GROUP_MASK ) <= ulMaxPRIGROUPValue ); } diff --git a/FreeRTOS/Source/portable/RVDS/ARM_CM7/r0p1/port.c b/FreeRTOS/Source/portable/RVDS/ARM_CM7/r0p1/port.c index c851e695b..e3ca6f4d3 100644 --- a/FreeRTOS/Source/portable/RVDS/ARM_CM7/r0p1/port.c +++ b/FreeRTOS/Source/portable/RVDS/ARM_CM7/r0p1/port.c @@ -139,20 +139,16 @@ is defined. */ #define portINITIAL_EXEC_RETURN ( 0xfffffffd ) /* The systick is a 24-bit counter. */ -#define portMAX_24_BIT_NUMBER ( 0xffffffUL ) +#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. */ -#define portMISSED_COUNTS_FACTOR ( 45UL ) +#define portMISSED_COUNTS_FACTOR ( 45UL ) /* For strict compliance with the Cortex-M spec the task start address should have bit-0 clear, as it is loaded into the PC on exit from an ISR. */ -#define portSTART_ADDRESS_MASK ( ( StackType_t ) 0xfffffffeUL ) - -/* Each task maintains its own interrupt status in the critical nesting -variable. */ -static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; +#define portSTART_ADDRESS_MASK ( ( StackType_t ) 0xfffffffeUL ) /* * Setup the timer to generate the tick interrupts. The implementation in this @@ -185,10 +181,14 @@ static void prvTaskExitError( void ); /*-----------------------------------------------------------*/ +/* Each task maintains its own interrupt status in the critical nesting +variable. */ +static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; + /* * The number of SysTick increments that make up one tick period. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulTimerCountsForOneTick = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -196,7 +196,7 @@ static void prvTaskExitError( void ); * 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 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t xMaximumPossibleSuppressedTicks = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -204,7 +204,7 @@ static void prvTaskExitError( void ); * Compensate for the CPU cycles that pass while the SysTick is stopped (low * power functionality only. */ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulStoppedTimerCompensation = 0; #endif /* configUSE_TICKLESS_IDLE */ @@ -547,11 +547,11 @@ void xPortSysTickHandler( void ) } /*-----------------------------------------------------------*/ -#if configUSE_TICKLESS_IDLE == 1 +#if( configUSE_TICKLESS_IDLE == 1 ) __weak void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime ) { - uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements, ulSysTickCTRL; + uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements; TickType_t xModifiableIdleTime; /* Make sure the SysTick reload value does not overflow the counter. */ @@ -627,23 +627,41 @@ void xPortSysTickHandler( void ) } configPOST_SLEEP_PROCESSING( xExpectedIdleTime ); - /* Stop SysTick. 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. */ - ulSysTickCTRL = portNVIC_SYSTICK_CTRL_REG; - portNVIC_SYSTICK_CTRL_REG = ( ulSysTickCTRL & ~portNVIC_SYSTICK_ENABLE_BIT ); - - /* Re-enable interrupts - see comments above __disable_irq() call - above. */ + /* 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(); - - if( ( ulSysTickCTRL & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 ) + __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 has already executed, and the SysTick - count reloaded with ulReloadValue. Reset the + /* 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 ); @@ -658,11 +676,9 @@ void xPortSysTickHandler( void ) portNVIC_SYSTICK_LOAD_REG = ulCalculatedLoadValue; - /* The tick interrupt handler will already have pended the tick - processing in the kernel. 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. */ + /* 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 @@ -684,17 +700,14 @@ void xPortSysTickHandler( void ) /* Restart SysTick so it runs from portNVIC_SYSTICK_LOAD_REG again, then set portNVIC_SYSTICK_LOAD_REG back to its standard - value. The critical section is used to ensure the tick interrupt - can only execute once in the case that the reload register is near - zero. */ + value. */ portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL; - portENTER_CRITICAL(); - { - portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; - vTaskStepTick( ulCompleteTickPeriods ); - portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; - } - portEXIT_CRITICAL(); + portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; + vTaskStepTick( ulCompleteTickPeriods ); + portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; + + /* Exit with interrpts enabled. */ + __enable_irq(); } } @@ -706,12 +719,12 @@ void xPortSysTickHandler( void ) * Setup the SysTick timer to generate the tick interrupts at the required * frequency. */ -#if configOVERRIDE_DEFAULT_TICK_CONFIGURATION == 0 +#if( configOVERRIDE_DEFAULT_TICK_CONFIGURATION == 0 ) void vPortSetupTimerInterrupt( void ) { /* Calculate the constants required to configure the tick interrupt. */ - #if configUSE_TICKLESS_IDLE == 1 + #if( configUSE_TICKLESS_IDLE == 1 ) { ulTimerCountsForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ); xMaximumPossibleSuppressedTicks = portMAX_24_BIT_NUMBER / ulTimerCountsForOneTick; @@ -794,7 +807,7 @@ __asm uint32_t vPortGetIPSR( void ) devices by calling NVIC_SetPriorityGrouping( 0 ); before starting the scheduler. Note however that some vendor specific peripheral libraries assume a non-zero priority group setting, in which cases using a value - of zero will result in unpredicable behaviour. */ + of zero will result in unpredictable behaviour. */ configASSERT( ( portAIRCR_REG & portPRIORITY_GROUP_MASK ) <= ulMaxPRIGROUPValue ); }