/* * FreeRTOS Kernel V10.5.1 * Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved. * * SPDX-License-Identifier: MIT * * Permission is hereby granted, free of charge, to any person obtaining a copy of * this software and associated documentation files (the "Software"), to deal in * the Software without restriction, including without limitation the rights to * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of * the Software, and to permit persons to whom the Software is furnished to do so, * subject to the following conditions: * * The above copyright notice and this permission notice shall be included in all * copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. * * https://www.FreeRTOS.org * https://github.com/FreeRTOS * */ /*----------------------------------------------------------- * Implementation of functions defined in portable.h for the ARM CM4F port. *----------------------------------------------------------*/ /* Scheduler includes. */ #include "FreeRTOS.h" #include "task.h" /* Constants required to manipulate the core. Registers first... */ #define portNVIC_SYSTICK_CTRL_REG ( *( ( volatile uint32_t * ) 0xe000e010 ) ) #define portNVIC_SYSTICK_LOAD_REG ( *( ( volatile uint32_t * ) 0xe000e014 ) ) #define portNVIC_SYSTICK_CURRENT_VALUE_REG ( *( ( volatile uint32_t * ) 0xe000e018 ) ) #define portNVIC_SHPR3_REG ( *( ( volatile uint32_t * ) 0xe000ed20 ) ) /* ...then bits in the registers. */ #define portNVIC_SYSTICK_CLK_BIT ( 1UL << 2UL ) #define portNVIC_SYSTICK_INT_BIT ( 1UL << 1UL ) #define portNVIC_SYSTICK_ENABLE_BIT ( 1UL << 0UL ) #define portNVIC_SYSTICK_COUNT_FLAG_BIT ( 1UL << 16UL ) #define portNVIC_PENDSVCLEAR_BIT ( 1UL << 27UL ) #define portNVIC_PEND_SYSTICK_SET_BIT ( 1UL << 26UL ) #define portNVIC_PEND_SYSTICK_CLEAR_BIT ( 1UL << 25UL ) #define portNVIC_PENDSV_PRI ( ( ( uint32_t ) configKERNEL_INTERRUPT_PRIORITY ) << 16UL ) #define portNVIC_SYSTICK_PRI ( ( ( uint32_t ) configKERNEL_INTERRUPT_PRIORITY ) << 24UL ) /* Constants required to check the validity of an interrupt priority. */ #define portFIRST_USER_INTERRUPT_NUMBER ( 16 ) #define portNVIC_IP_REGISTERS_OFFSET_16 ( 0xE000E3F0 ) #define portAIRCR_REG ( *( ( volatile uint32_t * ) 0xE000ED0C ) ) #define portMAX_8_BIT_VALUE ( ( uint8_t ) 0xff ) #define portTOP_BIT_OF_BYTE ( ( uint8_t ) 0x80 ) #define portMAX_PRIGROUP_BITS ( ( uint8_t ) 7 ) #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 manipulate the VFP. */ #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_EXC_RETURN ( 0xfffffffd ) /* The systick is a 24-bit counter. */ #define portMAX_24_BIT_NUMBER ( 0xffffffUL ) /* A fiddle factor to estimate the number of SysTick counts that would have * occurred while the SysTick counter is stopped during tickless idle * calculations. */ #define portMISSED_COUNTS_FACTOR ( 94UL ) /* Let the user override the default SysTick clock rate. If defined by the * user, this symbol must equal the SysTick clock rate when the CLK bit is 0 in the * configuration register. */ #ifndef configSYSTICK_CLOCK_HZ #define configSYSTICK_CLOCK_HZ ( configCPU_CLOCK_HZ ) /* Ensure the SysTick is clocked at the same frequency as the core. */ #define portNVIC_SYSTICK_CLK_BIT_CONFIG ( portNVIC_SYSTICK_CLK_BIT ) #else /* Select the option to clock SysTick not at the same frequency as the core. */ #define portNVIC_SYSTICK_CLK_BIT_CONFIG ( 0 ) #endif /* 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. */ #ifdef configTASK_RETURN_ADDRESS #define portTASK_RETURN_ADDRESS configTASK_RETURN_ADDRESS #else #define portTASK_RETURN_ADDRESS prvTaskExitError #endif /* Cannot find a weak linkage attribute, so the * configOVERRIDE_DEFAULT_TICK_CONFIGURATION constant must be set to 1 if the * application writer wants to provide their own implementation of * vPortSetupTimerInterrupt(). Ensure configOVERRIDE_DEFAULT_TICK_CONFIGURATION * is defined. */ #ifndef configOVERRIDE_DEFAULT_TICK_CONFIGURATION #define configOVERRIDE_DEFAULT_TICK_CONFIGURATION 0 #endif /* Manual definition of missing asm names. */ #define psp 9 #define basepri 17 #define msp 8 #define ipsr 5 #define control 20 /* From port.c. */ extern void * pxCurrentTCB; /* 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 * generate the tick interrupt. */ void vPortSetupTimerInterrupt( void ); /* * Exception handlers. */ void xPortPendSVHandler( void ); void xPortSysTickHandler( void ); void vPortSVCHandler( void ); /* * Start first task is a separate function so it can be tested in isolation. */ static void prvPortStartFirstTask( void ); /* * Function to enable the VFP. */ static void vPortEnableVFP( void ); /* * Used to catch tasks that attempt to return from their implementing function. */ static void prvTaskExitError( void ); /*-----------------------------------------------------------*/ /* * The number of SysTick increments that make up one tick period. */ #if ( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulTimerCountsForOneTick = 0; #endif /* configUSE_TICKLESS_IDLE */ /* * The maximum number of tick periods that can be suppressed is limited by the * 24 bit resolution of the SysTick timer. */ #if ( configUSE_TICKLESS_IDLE == 1 ) static uint32_t xMaximumPossibleSuppressedTicks = 0; #endif /* configUSE_TICKLESS_IDLE */ /* * Compensate for the CPU cycles that pass while the SysTick is stopped (low * power functionality only. */ #if ( configUSE_TICKLESS_IDLE == 1 ) static uint32_t ulStoppedTimerCompensation = 0; #endif /* configUSE_TICKLESS_IDLE */ /* * Used by the portASSERT_IF_INTERRUPT_PRIORITY_INVALID() macro to ensure * FreeRTOS API functions are not called from interrupts that have been assigned * a priority above configMAX_SYSCALL_INTERRUPT_PRIORITY. */ #if ( configASSERT_DEFINED == 1 ) static uint8_t ucMaxSysCallPriority = 0; static uint32_t ulMaxPRIGROUPValue = 0; #endif /* configASSERT_DEFINED */ /*-----------------------------------------------------------*/ /* * See header file for description. */ StackType_t * pxPortInitialiseStack( StackType_t * pxTopOfStack, TaskFunction_t pxCode, void * pvParameters ) { /* Simulate the stack frame as it would be created by a context switch * interrupt. */ /* Offset added to account for the way the MCU uses the stack on entry/exit * of interrupts, and to ensure alignment. */ pxTopOfStack--; /* Sometimes the parameters are loaded from the stack. */ *pxTopOfStack = ( StackType_t ) pvParameters; pxTopOfStack--; *pxTopOfStack = portINITIAL_XPSR; /* xPSR */ pxTopOfStack--; *pxTopOfStack = ( StackType_t ) pxCode; /* PC */ pxTopOfStack--; *pxTopOfStack = ( StackType_t ) portTASK_RETURN_ADDRESS; /* LR */ /* Save code space by skipping register initialisation. */ pxTopOfStack -= 5; /* R12, R3, R2 and R1. */ *pxTopOfStack = ( StackType_t ) pvParameters; /* R0 */ /* A save method is being used that requires each task to maintain its * own exec return value. */ pxTopOfStack--; *pxTopOfStack = portINITIAL_EXC_RETURN; pxTopOfStack -= 8; /* R11, R10, R9, R8, R7, R6, R5 and R4. */ return pxTopOfStack; } /*-----------------------------------------------------------*/ static void prvTaskExitError( void ) { /* A function that implements a task must not exit or attempt to return to * its caller as there is nothing to return to. If a task wants to exit it * should instead call vTaskDelete( NULL ). * * Artificially force an assert() to be triggered if configASSERT() is * defined, then stop here so application writers can catch the error. */ configASSERT( uxCriticalNesting == ~0UL ); portDISABLE_INTERRUPTS(); for( ; ; ) { } } /*-----------------------------------------------------------*/ void vPortSVCHandler( void ) iv IVT_INT_SVCall ics ICS_OFF { __asm { /* *INDENT-OFF* */ ldr r3, =_pxCurrentTCB /* Restore the context. */ ldr r1, [ r3 ] /* Use pxCurrentTCBConst to get the pxCurrentTCB address. */ ldr r0, [ r1 ] /* The first item in pxCurrentTCB is the task top of stack. */ ldm r0 !, ( r4 - r11, r14 ) /* Pop the registers that are not automatically saved on exception entry and the critical nesting count. */ msr psp, r0 /* Restore the task stack pointer. */ isb mov r0, #0 msr basepri, r0 bx r14 /* *INDENT-ON* */ }; } /*-----------------------------------------------------------*/ static void prvPortStartFirstTask( void ) { __asm { /* *INDENT-OFF* */ ldr r0, =0xE000ED08 /* Use the NVIC offset register to locate the stack. */ ldr r0, [ r0 ] ldr r0, [ r0 ] msr msp, r0 /* Set the msp back to the start of the stack. */ /* Clear the bit that indicates the FPU is in use in case the FPU was used * before the scheduler was started - which would otherwise result in the * unnecessary leaving of space in the SVC stack for lazy saving of FPU * registers. */ mov r0, #0 msr control, r0 cpsie i /* Globally enable interrupts. */ cpsie f dsb isb svc #0 /* System call to start first task. */ nop /* *INDENT-ON* */ }; } /*-----------------------------------------------------------*/ /* * See header file for description. */ BaseType_t xPortStartScheduler( void ) { /* configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to 0. * See https://www.FreeRTOS.org/RTOS-Cortex-M3-M4.html */ configASSERT( configMAX_SYSCALL_INTERRUPT_PRIORITY ); #if ( configASSERT_DEFINED == 1 ) { volatile uint32_t ulOriginalPriority; volatile uint8_t * const pucFirstUserPriorityRegister = ( volatile uint8_t * const ) ( portNVIC_IP_REGISTERS_OFFSET_16 + portFIRST_USER_INTERRUPT_NUMBER ); volatile uint8_t ucMaxPriorityValue; /* Determine the maximum priority from which ISR safe FreeRTOS API * functions can be called. ISR safe functions are those that end in * "FromISR". FreeRTOS maintains separate thread and ISR API functions to * ensure interrupt entry is as fast and simple as possible. * * Save the interrupt priority value that is about to be clobbered. */ ulOriginalPriority = *pucFirstUserPriorityRegister; /* Determine the number of priority bits available. First write to all * possible bits. */ *pucFirstUserPriorityRegister = portMAX_8_BIT_VALUE; /* 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; /* Calculate the maximum acceptable priority group value for the number * of bits read back. */ ulMaxPRIGROUPValue = portMAX_PRIGROUP_BITS; while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE ) { ulMaxPRIGROUPValue--; ucMaxPriorityValue <<= ( uint8_t ) 0x01; } #ifdef __NVIC_PRIO_BITS { /* Check the CMSIS configuration that defines the number of * priority bits matches the number of priority bits actually queried * from the hardware. */ configASSERT( ( portMAX_PRIGROUP_BITS - ulMaxPRIGROUPValue ) == __NVIC_PRIO_BITS ); } #endif #ifdef configPRIO_BITS { /* Check the FreeRTOS configuration that defines the number of * priority bits matches the number of priority bits actually queried * from the hardware. */ configASSERT( ( portMAX_PRIGROUP_BITS - ulMaxPRIGROUPValue ) == configPRIO_BITS ); } #endif /* Shift the priority group value back to its position within the AIRCR * register. */ ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT; ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK; /* Restore the clobbered interrupt priority register to its original * value. */ *pucFirstUserPriorityRegister = ulOriginalPriority; } #endif /* configASSERT_DEFINED */ /* Make PendSV and SysTick the lowest priority interrupts. */ portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI; portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI; /* Start the timer that generates the tick ISR. Interrupts are disabled * here already. */ vPortSetupTimerInterrupt(); /* Initialise the critical nesting count ready for the first task. */ uxCriticalNesting = 0; /* Ensure the VFP is enabled - it should be anyway. */ vPortEnableVFP(); /* Lazy save always. */ *( portFPCCR ) |= portASPEN_AND_LSPEN_BITS; /* Start the first task. */ prvPortStartFirstTask(); /* 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. */ prvTaskExitError(); /* Should not get here! */ return 0; } /*-----------------------------------------------------------*/ void vPortEndScheduler( void ) { /* Not implemented in ports where there is nothing to return to. * Artificially force an assert. */ configASSERT( uxCriticalNesting == 1000UL ); } /*-----------------------------------------------------------*/ void vPortEnterCritical( void ) { portDISABLE_INTERRUPTS(); uxCriticalNesting++; /* This is not the interrupt safe version of the enter critical function so * assert() if it is being called from an interrupt context. Only API * functions that end in "FromISR" can be used in an interrupt. Only assert if * the critical nesting count is 1 to protect against recursive calls if the * assert function also uses a critical section. */ if( uxCriticalNesting == 1 ) { configASSERT( ( portNVIC_INT_CTRL_REG & portVECTACTIVE_MASK ) == 0 ); } } /*-----------------------------------------------------------*/ void vPortExitCritical( void ) { configASSERT( uxCriticalNesting ); uxCriticalNesting--; if( uxCriticalNesting == 0 ) { portENABLE_INTERRUPTS(); } } /*-----------------------------------------------------------*/ const uint8_t ucMaxSyscallInterruptPriority = configMAX_SYSCALL_INTERRUPT_PRIORITY; void xPortPendSVHandler( void ) iv IVT_INT_PendSV ics ICS_OFF { __asm { #ifdef HW_DEBUG /* *INDENT-OFF* */ /* The function is not truly naked, so add back the 4 bytes subtracted * from the stack pointer by the function prologue. */ add sp, sp, # 4 #endif mrs r0, psp isb ldr r3, =_pxCurrentTCB /* Get the location of the current TCB. */ ldr r2, [ r3 ] tst r14, #0x10 /* Is the task using the FPU context? If so, push high vfp registers. */ it eq vstmdbeq r0 !, ( s16 - s31 ) stmdb r0 !, ( r4 - r11, r14 ) /* Save the core registers. */ str r0, [ r2 ] /* Save the new top of stack into the first member of the TCB. */ stmdb sp !, ( r0, r3 ) ldr r0, = _ucMaxSyscallInterruptPriority ldr r1, [ r0 ] msr basepri, r1 dsb isb bl _vTaskSwitchContext mov r0, #0 msr basepri, r0 ldm sp !, ( r0, r3 ) ldr r1, [ r3 ] /* The first item in pxCurrentTCB is the task top of stack. */ ldr r0, [ r1 ] ldm r0 !, ( r4 - r11, r14 ) /* Pop the core registers. */ tst r14, #0x10 /* Is the task using the FPU context? If so, pop the high vfp registers too. */ it eq vldmiaeq r0 !, ( s16 - s31 ) msr psp, r0 isb bx r14 /* *INDENT-ON* */ } } /*-----------------------------------------------------------*/ void xPortSysTickHandler( void ) iv IVT_INT_SysTick ics ICS_AUTO { /* The SysTick runs at the lowest interrupt priority, so when this interrupt * executes all interrupts must be unmasked. There is therefore no need to * save and then restore the interrupt mask value as its value is already * known - therefore the slightly faster portDISABLE_INTERRUPTS() function is * used in place of portSET_INTERRUPT_MASK_FROM_ISR(). */ portDISABLE_INTERRUPTS(); { /* Increment the RTOS tick. */ if( xTaskIncrementTick() != pdFALSE ) { /* A context switch is required. Context switching is performed in * the PendSV interrupt. Pend the PendSV interrupt. */ portNVIC_INT_CTRL_REG = portNVIC_PENDSVSET_BIT; } } portENABLE_INTERRUPTS(); } /*-----------------------------------------------------------*/ #if ( ( configUSE_TICKLESS_IDLE == 1 ) && ( configOVERRIDE_DEFAULT_TICK_CONFIGURATION == 0 ) ) void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime ) { uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements, ulSysTickDecrementsLeft; TickType_t xModifiableIdleTime; /* Make sure the SysTick reload value does not overflow the counter. */ if( xExpectedIdleTime > xMaximumPossibleSuppressedTicks ) { xExpectedIdleTime = xMaximumPossibleSuppressedTicks; } /* Enter a critical section but don't use the taskENTER_CRITICAL() * method as that will mask interrupts that should exit sleep mode. */ __asm { "cpsid i" }; __asm { "dsb" }; __asm { "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 ) { /* Re-enable interrupts - see comments above the cpsid instruction * above. */ __asm { "cpsie i" }; } else { /* Stop the SysTick momentarily. The time the SysTick is stopped for * is accounted for as best it can be, but using the tickless mode will * inevitably result in some tiny drift of the time maintained by the * kernel with respect to calendar time. */ portNVIC_SYSTICK_CTRL_REG = ( portNVIC_SYSTICK_CLK_BIT_CONFIG | portNVIC_SYSTICK_INT_BIT ); /* Use the SysTick current-value register to determine the number of * SysTick decrements remaining until the next tick interrupt. If the * current-value register is zero, then there are actually * ulTimerCountsForOneTick decrements remaining, not zero, because the * SysTick requests the interrupt when decrementing from 1 to 0. */ ulSysTickDecrementsLeft = portNVIC_SYSTICK_CURRENT_VALUE_REG; if( ulSysTickDecrementsLeft == 0 ) { ulSysTickDecrementsLeft = ulTimerCountsForOneTick; } /* Calculate the reload value required to wait xExpectedIdleTime * tick periods. -1 is used because this code normally executes part * way through the first tick period. But if the SysTick IRQ is now * pending, then clear the IRQ, suppressing the first tick, and correct * the reload value to reflect that the second tick period is already * underway. The expected idle time is always at least two ticks. */ ulReloadValue = ulSysTickDecrementsLeft + ( ulTimerCountsForOneTick * ( xExpectedIdleTime - 1UL ) ); if( ( portNVIC_INT_CTRL_REG & portNVIC_PEND_SYSTICK_SET_BIT ) != 0 ) { portNVIC_INT_CTRL_REG = portNVIC_PEND_SYSTICK_CLEAR_BIT; ulReloadValue -= ulTimerCountsForOneTick; } if( ulReloadValue > ulStoppedTimerCompensation ) { ulReloadValue -= ulStoppedTimerCompensation; } /* Set the new reload value. */ portNVIC_SYSTICK_LOAD_REG = ulReloadValue; /* Clear the SysTick count flag and set the count value back to * zero. */ portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL; /* Restart SysTick. */ portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; /* Sleep until something happens. configPRE_SLEEP_PROCESSING() can * set its parameter to 0 to indicate that its implementation contains * its own wait for interrupt or wait for event instruction, and so wfi * should not be executed again. However, the original expected idle * time variable must remain unmodified, so a copy is taken. */ xModifiableIdleTime = xExpectedIdleTime; configPRE_SLEEP_PROCESSING( xModifiableIdleTime ); if( xModifiableIdleTime > 0 ) { __asm { "dsb" }; __asm { "wfi" }; __asm { "isb" }; } configPOST_SLEEP_PROCESSING( xExpectedIdleTime ); /* Re-enable interrupts to allow the interrupt that brought the MCU * out of sleep mode to execute immediately. See comments above * the cpsid instruction above. */ __asm { "cpsie i" }; __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_CONFIG | portNVIC_SYSTICK_INT_BIT ); /* Determine whether the SysTick has already counted to zero. */ if( ( portNVIC_SYSTICK_CTRL_REG & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 ) { uint32_t ulCalculatedLoadValue; /* The tick interrupt ended the sleep (or is now pending), and * a new tick period has started. Reset portNVIC_SYSTICK_LOAD_REG * with whatever remains of the new tick period. */ ulCalculatedLoadValue = ( ulTimerCountsForOneTick - 1UL ) - ( ulReloadValue - portNVIC_SYSTICK_CURRENT_VALUE_REG ); /* Don't allow a tiny value, or values that have somehow * underflowed because the post sleep hook did something * that took too long or because the SysTick current-value register * is zero. */ if( ( ulCalculatedLoadValue <= ulStoppedTimerCompensation ) || ( ulCalculatedLoadValue > ulTimerCountsForOneTick ) ) { ulCalculatedLoadValue = ( ulTimerCountsForOneTick - 1UL ); } portNVIC_SYSTICK_LOAD_REG = ulCalculatedLoadValue; /* As the pending tick will be processed as soon as this * function exits, the tick value maintained by the tick is stepped * forward by one less than the time spent waiting. */ ulCompleteTickPeriods = xExpectedIdleTime - 1UL; } else { /* Something other than the tick interrupt ended the sleep. */ /* Use the SysTick current-value register to determine the * number of SysTick decrements remaining until the expected idle * time would have ended. */ ulSysTickDecrementsLeft = portNVIC_SYSTICK_CURRENT_VALUE_REG; #if ( portNVIC_SYSTICK_CLK_BIT_CONFIG != portNVIC_SYSTICK_CLK_BIT ) { /* If the SysTick is not using the core clock, the current- * value register might still be zero here. In that case, the * SysTick didn't load from the reload register, and there are * ulReloadValue decrements remaining in the expected idle * time, not zero. */ if( ulSysTickDecrementsLeft == 0 ) { ulSysTickDecrementsLeft = ulReloadValue; } } #endif /* portNVIC_SYSTICK_CLK_BIT_CONFIG */ /* Work out how long the sleep lasted rounded to complete tick * periods (not the ulReload value which accounted for part * ticks). */ ulCompletedSysTickDecrements = ( xExpectedIdleTime * ulTimerCountsForOneTick ) - ulSysTickDecrementsLeft; /* How many complete tick periods passed while the processor * was waiting? */ ulCompleteTickPeriods = ulCompletedSysTickDecrements / ulTimerCountsForOneTick; /* The reload value is set to whatever fraction of a single tick * period remains. */ portNVIC_SYSTICK_LOAD_REG = ( ( ulCompleteTickPeriods + 1UL ) * ulTimerCountsForOneTick ) - ulCompletedSysTickDecrements; } /* Restart SysTick so it runs from portNVIC_SYSTICK_LOAD_REG again, * then set portNVIC_SYSTICK_LOAD_REG back to its standard value. If * the SysTick is not using the core clock, temporarily configure it to * use the core clock. This configuration forces the SysTick to load * from portNVIC_SYSTICK_LOAD_REG immediately instead of at the next * cycle of the other clock. Then portNVIC_SYSTICK_LOAD_REG is ready * to receive the standard value immediately. */ portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL; portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT; #if ( portNVIC_SYSTICK_CLK_BIT_CONFIG == portNVIC_SYSTICK_CLK_BIT ) { portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; } #else { /* The temporary usage of the core clock has served its purpose, * as described above. Resume usage of the other clock. */ portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT; if( ( portNVIC_SYSTICK_CTRL_REG & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 ) { /* The partial tick period already ended. Be sure the SysTick * counts it only once. */ portNVIC_SYSTICK_CURRENT_VALUE_REG = 0; } portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT_CONFIG | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT; } #endif /* portNVIC_SYSTICK_CLK_BIT_CONFIG */ /* Step the tick to account for any tick periods that elapsed. */ vTaskStepTick( ulCompleteTickPeriods ); /* Exit with interrupts enabled. */ __asm { "cpsie i" }; } } #endif /* #if configUSE_TICKLESS_IDLE */ /*-----------------------------------------------------------*/ /* * Setup the systick timer to generate the tick interrupts at the required * frequency. */ #if ( configOVERRIDE_DEFAULT_TICK_CONFIGURATION == 0 ) void vPortSetupTimerInterrupt( void ) { /* Calculate the constants required to configure the tick interrupt. */ #if ( configUSE_TICKLESS_IDLE == 1 ) { ulTimerCountsForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ); xMaximumPossibleSuppressedTicks = portMAX_24_BIT_NUMBER / ulTimerCountsForOneTick; ulStoppedTimerCompensation = portMISSED_COUNTS_FACTOR / ( configCPU_CLOCK_HZ / configSYSTICK_CLOCK_HZ ); } #endif /* configUSE_TICKLESS_IDLE */ /* Reset SysTick. */ portNVIC_SYSTICK_CTRL_REG = 0UL; portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL; /* Configure SysTick to interrupt at the requested rate. */ portNVIC_SYSTICK_LOAD_REG = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL; portNVIC_SYSTICK_CTRL_REG = ( portNVIC_SYSTICK_CLK_BIT_CONFIG | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT ); } #endif /* configOVERRIDE_DEFAULT_TICK_CONFIGURATION */ /*-----------------------------------------------------------*/ /* This is a naked function. */ static void vPortEnableVFP( void ) { __asm { /* *INDENT-OFF* */ ldr r0, =0xE000ED88 /* The FPU enable bits are in the CPACR. */ ldr r1, [ r0 ] orr r1, r1, #0xF00000 /* Enable CP10 and CP11 coprocessors, then save back. */ str r1, [ r0 ] bx r14 /* *INDENT-ON* */ }; } /*-----------------------------------------------------------*/ BaseType_t xPortIsInsideInterrupt( void ) { BaseType_t xReturn; /* Obtain the number of the currently executing interrupt. */ if( CPU_REG_GET( CPU_IPSR ) == 0 ) { xReturn = pdFALSE; } else { xReturn = pdTRUE; } return xReturn; } /*-----------------------------------------------------------*/ #if ( configASSERT_DEFINED == 1 ) /* Limitations in the MikroC inline asm means ulCurrentInterrupt has to be * global - which makes vPortValidateInterruptPriority() non re-entrant. * However that should not matter as an interrupt can only itself be * interrupted by a higher priority interrupt. That means if * ulCurrentInterrupt, so ulCurrentInterrupt getting corrupted cannot lead to * an invalid interrupt priority being missed. */ uint32_t ulCurrentInterrupt; uint8_t ucCurrentPriority; void vPortValidateInterruptPriority( void ) { /* Obtain the number of the currently executing interrupt. */ __asm { /* *INDENT-OFF* */ push( r0, r1 ) mrs r0, ipsr ldr r1, =_ulCurrentInterrupt str r0, [ r1 ] pop( r0, r1 ) /* *INDENT-ON* */ }; /* Is the interrupt number a user defined interrupt? */ if( ulCurrentInterrupt >= portFIRST_USER_INTERRUPT_NUMBER ) { /* Look up the interrupt's priority. */ ucCurrentPriority = *( ( uint8_t * ) ( portNVIC_IP_REGISTERS_OFFSET_16 + ulCurrentInterrupt ) ); /* The following assertion will fail if a service routine (ISR) for * an interrupt that has been assigned a priority above * configMAX_SYSCALL_INTERRUPT_PRIORITY calls an ISR safe FreeRTOS API * function. ISR safe FreeRTOS API functions must *only* be called * from interrupts that have been assigned a priority at or below * configMAX_SYSCALL_INTERRUPT_PRIORITY. * * Numerically low interrupt priority numbers represent logically high * interrupt priorities, therefore the priority of the interrupt must * be set to a value equal to or numerically *higher* than * configMAX_SYSCALL_INTERRUPT_PRIORITY. * * Interrupts that use the FreeRTOS API must not be left at their * default priority of zero as that is the highest possible priority, * which is guaranteed to be above configMAX_SYSCALL_INTERRUPT_PRIORITY, * and therefore also guaranteed to be invalid. * * FreeRTOS maintains separate thread and ISR API functions to ensure * interrupt entry is as fast and simple as possible. * * The following links provide detailed information: * https://www.FreeRTOS.org/RTOS-Cortex-M3-M4.html * https://www.FreeRTOS.org/FAQHelp.html */ configASSERT( ucCurrentPriority >= ucMaxSysCallPriority ); } /* Priority grouping: The interrupt controller (NVIC) allows the bits * that define each interrupt's priority to be split between bits that * define the interrupt's pre-emption priority bits and bits that define * the interrupt's sub-priority. For simplicity all bits must be defined * to be pre-emption priority bits. The following assertion will fail if * this is not the case (if some bits represent a sub-priority). * * If the application only uses CMSIS libraries for interrupt * configuration then the correct setting can be achieved on all Cortex-M * 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 unpredictable behaviour. */ configASSERT( ( portAIRCR_REG & portPRIORITY_GROUP_MASK ) <= ulMaxPRIGROUPValue ); } #endif /* configASSERT_DEFINED */