| /* | |
| * FreeRTOS Kernel <DEVELOPMENT BRANCH> | |
| * 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" | |
| #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 ( 1UL << 2UL ) | |
| #else | |
| /* The way the SysTick is clocked is not modified in case it is not the same | |
| * as the core. */ | |
| #define portNVIC_SYSTICK_CLK_BIT ( 0 ) | |
| #endif | |
| /* 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_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_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 ( 45UL ) | |
| /* 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; | |
| TickType_t xModifiableIdleTime; | |
| /* Make sure the SysTick reload value does not overflow the counter. */ | |
| if( xExpectedIdleTime > xMaximumPossibleSuppressedTicks ) | |
| { | |
| xExpectedIdleTime = xMaximumPossibleSuppressedTicks; | |
| } | |
| /* Stop the SysTick momentarily. The time the SysTick is stopped for | |
| * is accounted for as best it can be, but using the tickless mode will | |
| * inevitably result in some tiny drift of the time maintained by the | |
| * kernel with respect to calendar time. */ | |
| portNVIC_SYSTICK_CTRL_REG &= ~portNVIC_SYSTICK_ENABLE_BIT; | |
| /* Calculate the reload value required to wait xExpectedIdleTime | |
| * tick periods. -1 is used because this code will execute part way | |
| * through one of the tick periods. */ | |
| ulReloadValue = portNVIC_SYSTICK_CURRENT_VALUE_REG + ( ulTimerCountsForOneTick * ( xExpectedIdleTime - 1UL ) ); | |
| if( ulReloadValue > ulStoppedTimerCompensation ) | |
| { | |
| ulReloadValue -= ulStoppedTimerCompensation; | |
| } | |
| /* Enter a critical section but don't use the taskENTER_CRITICAL() | |
| * method as that will mask interrupts that should exit sleep mode. */ | |
| __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 ) | |
| { | |
| /* Restart from whatever is left in the count register to complete | |
| * this tick period. */ | |
| portNVIC_SYSTICK_LOAD_REG = portNVIC_SYSTICK_CURRENT_VALUE_REG; | |
| /* Restart SysTick. */ | |
| portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; | |
| /* Reset the reload register to the value required for normal tick | |
| * periods. */ | |
| portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; | |
| /* Re-enable interrupts - see comments above the cpsid instruction() | |
| * above. */ | |
| __asm { | |
| "cpsie i" | |
| }; | |
| } | |
| else | |
| { | |
| /* Set the new reload value. */ | |
| portNVIC_SYSTICK_LOAD_REG = ulReloadValue; | |
| /* Clear the SysTick count flag and set the count value back to | |
| * zero. */ | |
| portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL; | |
| /* Restart SysTick. */ | |
| portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; | |
| /* Sleep until something happens. configPRE_SLEEP_PROCESSING() can | |
| * set its parameter to 0 to indicate that its implementation contains | |
| * its own wait for interrupt or wait for event instruction, and so wfi | |
| * should not be executed again. However, the original expected idle | |
| * time variable must remain unmodified, so a copy is taken. */ | |
| xModifiableIdleTime = xExpectedIdleTime; | |
| configPRE_SLEEP_PROCESSING( xModifiableIdleTime ); | |
| if( xModifiableIdleTime > 0 ) | |
| { | |
| __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 | |
| * __disable_interrupt() call 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 | portNVIC_SYSTICK_INT_BIT ); | |
| /* Determine if the SysTick clock has already counted to zero and | |
| * been set back to the current reload value (the reload back being | |
| * correct for the entire expected idle time) or if the SysTick is yet | |
| * to count to zero (in which case an interrupt other than the SysTick | |
| * must have brought the system out of sleep mode). */ | |
| if( ( portNVIC_SYSTICK_CTRL_REG & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 ) | |
| { | |
| uint32_t ulCalculatedLoadValue; | |
| /* The tick interrupt is already pending, and the SysTick count | |
| * reloaded with ulReloadValue. Reset the | |
| * portNVIC_SYSTICK_LOAD_REG with whatever remains of this tick | |
| * period. */ | |
| ulCalculatedLoadValue = ( ulTimerCountsForOneTick - 1UL ) - ( ulReloadValue - portNVIC_SYSTICK_CURRENT_VALUE_REG ); | |
| /* Don't allow a tiny value, or values that have somehow | |
| * underflowed because the post sleep hook did something | |
| * that took too long. */ | |
| if( ( ulCalculatedLoadValue < ulStoppedTimerCompensation ) || ( ulCalculatedLoadValue > ulTimerCountsForOneTick ) ) | |
| { | |
| ulCalculatedLoadValue = ( ulTimerCountsForOneTick - 1UL ); | |
| } | |
| portNVIC_SYSTICK_LOAD_REG = ulCalculatedLoadValue; | |
| /* As the pending tick will be processed as soon as this | |
| * function exits, the tick value maintained by the tick is stepped | |
| * forward by one less than the time spent waiting. */ | |
| ulCompleteTickPeriods = xExpectedIdleTime - 1UL; | |
| } | |
| else | |
| { | |
| /* Something other than the tick interrupt ended the sleep. | |
| * Work out how long the sleep lasted rounded to complete tick | |
| * periods (not the ulReload value which accounted for part | |
| * ticks). */ | |
| ulCompletedSysTickDecrements = ( xExpectedIdleTime * ulTimerCountsForOneTick ) - portNVIC_SYSTICK_CURRENT_VALUE_REG; | |
| /* How many complete tick periods passed while the processor | |
| * was waiting? */ | |
| ulCompleteTickPeriods = ulCompletedSysTickDecrements / ulTimerCountsForOneTick; | |
| /* The reload value is set to whatever fraction of a single tick | |
| * period remains. */ | |
| portNVIC_SYSTICK_LOAD_REG = ( ( ulCompleteTickPeriods + 1UL ) * ulTimerCountsForOneTick ) - ulCompletedSysTickDecrements; | |
| } | |
| /* Restart SysTick so it runs from portNVIC_SYSTICK_LOAD_REG | |
| * again, then set portNVIC_SYSTICK_LOAD_REG back to its standard | |
| * value. */ | |
| portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL; | |
| portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT; | |
| vTaskStepTick( ulCompleteTickPeriods ); | |
| portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL; | |
| /* Exit with 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 | 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 */ |