mirror of
https://github.com/FreeRTOS/FreeRTOS-Kernel.git
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c296e2cff8
- Clear the SysTick current value register before starting the SysTick (only required if something uses SysTick before starting the scheduler). - Ensure atomic operations are thread safe by executing clrex in the context switch.
656 lines
25 KiB
C
656 lines
25 KiB
C
/*
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FreeRTOS V9.0.0 - Copyright (C) 2016 Real Time Engineers Ltd.
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All rights reserved
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VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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This file is part of the FreeRTOS distribution.
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FreeRTOS is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License (version 2) as published by the
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Free Software Foundation >>>> AND MODIFIED BY <<<< the FreeRTOS exception.
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***************************************************************************
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>>! NOTE: The modification to the GPL is included to allow you to !<<
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>>! distribute a combined work that includes FreeRTOS without being !<<
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>>! obliged to provide the source code for proprietary components !<<
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>>! outside of the FreeRTOS kernel. !<<
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***************************************************************************
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FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. Full license text is available on the following
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link: http://www.freertos.org/a00114.html
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***************************************************************************
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* *
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* FreeRTOS provides completely free yet professionally developed, *
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* robust, strictly quality controlled, supported, and cross *
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* platform software that is more than just the market leader, it *
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* is the industry's de facto standard. *
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* *
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* Help yourself get started quickly while simultaneously helping *
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* to support the FreeRTOS project by purchasing a FreeRTOS *
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* tutorial book, reference manual, or both: *
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* http://www.FreeRTOS.org/Documentation *
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* *
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***************************************************************************
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http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading
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the FAQ page "My application does not run, what could be wrong?". Have you
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defined configASSERT()?
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http://www.FreeRTOS.org/support - In return for receiving this top quality
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embedded software for free we request you assist our global community by
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participating in the support forum.
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http://www.FreeRTOS.org/training - Investing in training allows your team to
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be as productive as possible as early as possible. Now you can receive
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FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
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Ltd, and the world's leading authority on the world's leading RTOS.
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http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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compatible FAT file system, and our tiny thread aware UDP/IP stack.
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http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
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Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
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http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
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Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
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licenses offer ticketed support, indemnification and commercial middleware.
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http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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engineered and independently SIL3 certified version for use in safety and
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mission critical applications that require provable dependability.
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1 tab == 4 spaces!
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*/
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/*-----------------------------------------------------------
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* Implementation of functions defined in portable.h for the ARM CM4F port.
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*----------------------------------------------------------*/
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/* Scheduler includes. */
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#include "FreeRTOS.h"
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#include "task.h"
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#ifndef __TI_VFP_SUPPORT__
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#error This port can only be used when the project options are configured to enable hardware floating point support.
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#endif
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#if configMAX_SYSCALL_INTERRUPT_PRIORITY == 0
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#error configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to 0. See http://www.FreeRTOS.org/RTOS-Cortex-M3-M4.html
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#endif
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#ifndef configSYSTICK_CLOCK_HZ
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#define configSYSTICK_CLOCK_HZ configCPU_CLOCK_HZ
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/* Ensure the SysTick is clocked at the same frequency as the core. */
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#define portNVIC_SYSTICK_CLK_BIT ( 1UL << 2UL )
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#else
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/* The way the SysTick is clocked is not modified in case it is not the same
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as the core. */
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#define portNVIC_SYSTICK_CLK_BIT ( 0 )
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#endif
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/* Constants required to manipulate the core. Registers first... */
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#define portNVIC_SYSTICK_CTRL_REG ( * ( ( volatile uint32_t * ) 0xe000e010 ) )
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#define portNVIC_SYSTICK_LOAD_REG ( * ( ( volatile uint32_t * ) 0xe000e014 ) )
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#define portNVIC_SYSTICK_CURRENT_VALUE_REG ( * ( ( volatile uint32_t * ) 0xe000e018 ) )
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#define portNVIC_SYSPRI2_REG ( * ( ( volatile uint32_t * ) 0xe000ed20 ) )
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/* ...then bits in the registers. */
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#define portNVIC_SYSTICK_INT_BIT ( 1UL << 1UL )
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#define portNVIC_SYSTICK_ENABLE_BIT ( 1UL << 0UL )
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#define portNVIC_SYSTICK_COUNT_FLAG_BIT ( 1UL << 16UL )
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#define portNVIC_PENDSVCLEAR_BIT ( 1UL << 27UL )
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#define portNVIC_PEND_SYSTICK_CLEAR_BIT ( 1UL << 25UL )
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#define portNVIC_PENDSV_PRI ( ( ( uint32_t ) configKERNEL_INTERRUPT_PRIORITY ) << 16UL )
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#define portNVIC_SYSTICK_PRI ( ( ( uint32_t ) configKERNEL_INTERRUPT_PRIORITY ) << 24UL )
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/* Constants required to check the validity of an interrupt priority. */
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#define portFIRST_USER_INTERRUPT_NUMBER ( 16 )
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#define portNVIC_IP_REGISTERS_OFFSET_16 ( 0xE000E3F0 )
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#define portAIRCR_REG ( * ( ( volatile uint32_t * ) 0xE000ED0C ) )
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#define portMAX_8_BIT_VALUE ( ( uint8_t ) 0xff )
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#define portTOP_BIT_OF_BYTE ( ( uint8_t ) 0x80 )
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#define portMAX_PRIGROUP_BITS ( ( uint8_t ) 7 )
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#define portPRIORITY_GROUP_MASK ( 0x07UL << 8UL )
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#define portPRIGROUP_SHIFT ( 8UL )
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/* Masks off all bits but the VECTACTIVE bits in the ICSR register. */
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#define portVECTACTIVE_MASK ( 0xFFUL )
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/* Constants required to manipulate the VFP. */
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#define portFPCCR ( ( volatile uint32_t * ) 0xe000ef34 ) /* Floating point context control register. */
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#define portASPEN_AND_LSPEN_BITS ( 0x3UL << 30UL )
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/* Constants required to set up the initial stack. */
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#define portINITIAL_XPSR ( 0x01000000 )
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#define portINITIAL_EXEC_RETURN ( 0xfffffffd )
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/* The systick is a 24-bit counter. */
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#define portMAX_24_BIT_NUMBER ( 0xffffffUL )
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/* A fiddle factor to estimate the number of SysTick counts that would have
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occurred while the SysTick counter is stopped during tickless idle
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calculations. */
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#define portMISSED_COUNTS_FACTOR ( 45UL )
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/* For strict compliance with the Cortex-M spec the task start address should
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have bit-0 clear, as it is loaded into the PC on exit from an ISR. */
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#define portSTART_ADDRESS_MASK ( ( StackType_t ) 0xfffffffeUL )
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/* Required to allow portasm.asm access the configMAX_SYSCALL_INTERRUPT_PRIORITY
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setting. */
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const uint32_t ulMaxSyscallInterruptPriority = configMAX_SYSCALL_INTERRUPT_PRIORITY;
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/* Each task maintains its own interrupt status in the critical nesting
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variable. */
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static UBaseType_t uxCriticalNesting = 0xaaaaaaaa;
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/*
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* Setup the timer to generate the tick interrupts. The implementation in this
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* file is weak to allow application writers to change the timer used to
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* generate the tick interrupt.
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*/
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void vPortSetupTimerInterrupt( void );
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/*
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* Exception handlers.
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*/
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void xPortSysTickHandler( void );
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/*
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* Start first task is a separate function so it can be tested in isolation.
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*/
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extern void vPortStartFirstTask( void );
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/*
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* Turn the VFP on.
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*/
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extern void vPortEnableVFP( void );
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/*
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* Used to catch tasks that attempt to return from their implementing function.
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*/
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static void prvTaskExitError( void );
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/*-----------------------------------------------------------*/
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/*
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* The number of SysTick increments that make up one tick period.
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*/
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#if configUSE_TICKLESS_IDLE == 1
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static uint32_t ulTimerCountsForOneTick = 0;
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#endif /* configUSE_TICKLESS_IDLE */
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/*
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* The maximum number of tick periods that can be suppressed is limited by the
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* 24 bit resolution of the SysTick timer.
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*/
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#if configUSE_TICKLESS_IDLE == 1
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static uint32_t xMaximumPossibleSuppressedTicks = 0;
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#endif /* configUSE_TICKLESS_IDLE */
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/*
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* Compensate for the CPU cycles that pass while the SysTick is stopped (low
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* power functionality only.
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*/
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#if configUSE_TICKLESS_IDLE == 1
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static uint32_t ulStoppedTimerCompensation = 0;
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#endif /* configUSE_TICKLESS_IDLE */
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/*
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* Used by the portASSERT_IF_INTERRUPT_PRIORITY_INVALID() macro to ensure
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* FreeRTOS API functions are not called from interrupts that have been assigned
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* a priority above configMAX_SYSCALL_INTERRUPT_PRIORITY.
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*/
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#if ( configASSERT_DEFINED == 1 )
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static uint8_t ucMaxSysCallPriority = 0;
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static uint32_t ulMaxPRIGROUPValue = 0;
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static const volatile uint8_t * const pcInterruptPriorityRegisters = ( uint8_t * ) portNVIC_IP_REGISTERS_OFFSET_16;
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#endif /* configASSERT_DEFINED */
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/*-----------------------------------------------------------*/
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/*
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* See header file for description.
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*/
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StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
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{
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/* Simulate the stack frame as it would be created by a context switch
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interrupt. */
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/* Offset added to account for the way the MCU uses the stack on entry/exit
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of interrupts, and to ensure alignment. */
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pxTopOfStack--;
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*pxTopOfStack = portINITIAL_XPSR; /* xPSR */
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pxTopOfStack--;
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*pxTopOfStack = ( ( StackType_t ) pxCode ) & portSTART_ADDRESS_MASK; /* PC */
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pxTopOfStack--;
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*pxTopOfStack = ( StackType_t ) prvTaskExitError; /* LR */
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/* Save code space by skipping register initialisation. */
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pxTopOfStack -= 5; /* R12, R3, R2 and R1. */
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*pxTopOfStack = ( StackType_t ) pvParameters; /* R0 */
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/* A save method is being used that requires each task to maintain its
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own exec return value. */
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pxTopOfStack--;
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*pxTopOfStack = portINITIAL_EXEC_RETURN;
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pxTopOfStack -= 8; /* R11, R10, R9, R8, R7, R6, R5 and R4. */
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return pxTopOfStack;
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}
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/*-----------------------------------------------------------*/
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static void prvTaskExitError( void )
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{
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/* A function that implements a task must not exit or attempt to return to
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its caller as there is nothing to return to. If a task wants to exit it
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should instead call vTaskDelete( NULL ).
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Artificially force an assert() to be triggered if configASSERT() is
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defined, then stop here so application writers can catch the error. */
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configASSERT( uxCriticalNesting == ~0UL );
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portDISABLE_INTERRUPTS();
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for( ;; );
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}
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/*-----------------------------------------------------------*/
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/*
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* See header file for description.
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*/
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BaseType_t xPortStartScheduler( void )
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{
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#if( configASSERT_DEFINED == 1 )
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{
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volatile uint32_t ulOriginalPriority;
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volatile uint8_t * const pucFirstUserPriorityRegister = ( uint8_t * ) ( portNVIC_IP_REGISTERS_OFFSET_16 + portFIRST_USER_INTERRUPT_NUMBER );
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volatile uint8_t ucMaxPriorityValue;
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/* Determine the maximum priority from which ISR safe FreeRTOS API
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functions can be called. ISR safe functions are those that end in
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"FromISR". FreeRTOS maintains separate thread and ISR API functions to
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ensure interrupt entry is as fast and simple as possible.
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Save the interrupt priority value that is about to be clobbered. */
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ulOriginalPriority = *pucFirstUserPriorityRegister;
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/* Determine the number of priority bits available. First write to all
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possible bits. */
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*pucFirstUserPriorityRegister = portMAX_8_BIT_VALUE;
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/* Read the value back to see how many bits stuck. */
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ucMaxPriorityValue = *pucFirstUserPriorityRegister;
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/* Use the same mask on the maximum system call priority. */
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ucMaxSysCallPriority = configMAX_SYSCALL_INTERRUPT_PRIORITY & ucMaxPriorityValue;
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/* Calculate the maximum acceptable priority group value for the number
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of bits read back. */
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ulMaxPRIGROUPValue = portMAX_PRIGROUP_BITS;
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while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
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{
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ulMaxPRIGROUPValue--;
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ucMaxPriorityValue <<= ( uint8_t ) 0x01;
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}
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/* Shift the priority group value back to its position within the AIRCR
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register. */
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ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
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ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
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/* Restore the clobbered interrupt priority register to its original
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value. */
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*pucFirstUserPriorityRegister = ulOriginalPriority;
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}
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#endif /* conifgASSERT_DEFINED */
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/* Make PendSV and SysTick the lowest priority interrupts. */
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portNVIC_SYSPRI2_REG |= portNVIC_PENDSV_PRI;
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portNVIC_SYSPRI2_REG |= portNVIC_SYSTICK_PRI;
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/* Start the timer that generates the tick ISR. Interrupts are disabled
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here already. */
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vPortSetupTimerInterrupt();
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/* Initialise the critical nesting count ready for the first task. */
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uxCriticalNesting = 0;
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/* Ensure the VFP is enabled - it should be anyway. */
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vPortEnableVFP();
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/* Lazy save always. */
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*( portFPCCR ) |= portASPEN_AND_LSPEN_BITS;
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/* Start the first task. */
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vPortStartFirstTask();
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/* Should not get here! */
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return 0;
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}
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/*-----------------------------------------------------------*/
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void vPortEndScheduler( void )
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{
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/* Not implemented in ports where there is nothing to return to.
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Artificially force an assert. */
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configASSERT( uxCriticalNesting == 1000UL );
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}
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/*-----------------------------------------------------------*/
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void vPortEnterCritical( void )
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{
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portDISABLE_INTERRUPTS();
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uxCriticalNesting++;
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/* This is not the interrupt safe version of the enter critical function so
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assert() if it is being called from an interrupt context. Only API
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functions that end in "FromISR" can be used in an interrupt. Only assert if
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the critical nesting count is 1 to protect against recursive calls if the
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assert function also uses a critical section. */
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if( uxCriticalNesting == 1 )
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{
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configASSERT( ( portNVIC_INT_CTRL_REG & portVECTACTIVE_MASK ) == 0 );
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}
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}
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/*-----------------------------------------------------------*/
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void vPortExitCritical( void )
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{
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configASSERT( uxCriticalNesting );
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uxCriticalNesting--;
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if( uxCriticalNesting == 0 )
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{
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portENABLE_INTERRUPTS();
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}
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}
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/*-----------------------------------------------------------*/
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void xPortSysTickHandler( void )
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{
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/* The SysTick runs at the lowest interrupt priority, so when this interrupt
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executes all interrupts must be unmasked. There is therefore no need to
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save and then restore the interrupt mask value as its value is already
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known. */
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( void ) portSET_INTERRUPT_MASK_FROM_ISR();
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{
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/* Increment the RTOS tick. */
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if( xTaskIncrementTick() != pdFALSE )
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{
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/* A context switch is required. Context switching is performed in
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the PendSV interrupt. Pend the PendSV interrupt. */
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portNVIC_INT_CTRL_REG = portNVIC_PENDSVSET_BIT;
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}
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}
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portCLEAR_INTERRUPT_MASK_FROM_ISR( 0 );
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}
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/*-----------------------------------------------------------*/
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#if configUSE_TICKLESS_IDLE == 1
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#pragma WEAK( vPortSuppressTicksAndSleep )
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void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime )
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{
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uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements, ulSysTickCTRL;
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TickType_t xModifiableIdleTime;
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/* Make sure the SysTick reload value does not overflow the counter. */
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if( xExpectedIdleTime > xMaximumPossibleSuppressedTicks )
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{
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xExpectedIdleTime = xMaximumPossibleSuppressedTicks;
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}
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/* Stop the SysTick momentarily. The time the SysTick is stopped for
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is accounted for as best it can be, but using the tickless mode will
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inevitably result in some tiny drift of the time maintained by the
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kernel with respect to calendar time. */
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portNVIC_SYSTICK_CTRL_REG &= ~portNVIC_SYSTICK_ENABLE_BIT;
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/* Calculate the reload value required to wait xExpectedIdleTime
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tick periods. -1 is used because this code will execute part way
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through one of the tick periods. */
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ulReloadValue = portNVIC_SYSTICK_CURRENT_VALUE_REG + ( ulTimerCountsForOneTick * ( xExpectedIdleTime - 1UL ) );
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if( ulReloadValue > ulStoppedTimerCompensation )
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{
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ulReloadValue -= ulStoppedTimerCompensation;
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}
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/* Enter a critical section but don't use the taskENTER_CRITICAL()
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method as that will mask interrupts that should exit sleep mode. */
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__asm( " cpsid i" );
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__asm( " dsb" );
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__asm( " isb" );
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/* If a context switch is pending or a task is waiting for the scheduler
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to be unsuspended then abandon the low power entry. */
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if( eTaskConfirmSleepModeStatus() == eAbortSleep )
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{
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/* Restart from whatever is left in the count register to complete
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this tick period. */
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portNVIC_SYSTICK_LOAD_REG = portNVIC_SYSTICK_CURRENT_VALUE_REG;
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/* Restart SysTick. */
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portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT;
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/* Reset the reload register to the value required for normal tick
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periods. */
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portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL;
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/* Re-enable interrupts - see comments above __disable_interrupt()
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call above. */
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__asm( " cpsie i" );
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}
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else
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{
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/* Set the new reload value. */
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portNVIC_SYSTICK_LOAD_REG = ulReloadValue;
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/* Clear the SysTick count flag and set the count value back to
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zero. */
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portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;
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/* Restart SysTick. */
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portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT;
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/* Sleep until something happens. configPRE_SLEEP_PROCESSING() can
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set its parameter to 0 to indicate that its implementation contains
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its own wait for interrupt or wait for event instruction, and so wfi
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should not be executed again. However, the original expected idle
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time variable must remain unmodified, so a copy is taken. */
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xModifiableIdleTime = xExpectedIdleTime;
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configPRE_SLEEP_PROCESSING( xModifiableIdleTime );
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if( xModifiableIdleTime > 0 )
|
|
{
|
|
__asm( " dsb" );
|
|
__asm( " wfi" );
|
|
__asm( " isb" );
|
|
}
|
|
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. */
|
|
__asm( " cpsie i" );
|
|
|
|
if( ( ulSysTickCTRL & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 )
|
|
{
|
|
uint32_t ulCalculatedLoadValue;
|
|
|
|
/* The tick interrupt has already executed, 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;
|
|
|
|
/* 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. */
|
|
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. The critical section is used to ensure the tick interrupt
|
|
can only execute once in the case that the reload register is near
|
|
zero. */
|
|
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();
|
|
}
|
|
}
|
|
|
|
#endif /* #if configUSE_TICKLESS_IDLE */
|
|
/*-----------------------------------------------------------*/
|
|
|
|
/*
|
|
* Setup the systick timer to generate the tick interrupts at the required
|
|
* frequency.
|
|
*/
|
|
#pragma WEAK( vPortSetupTimerInterrupt )
|
|
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 */
|
|
|
|
/* Stop and clear the 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 );
|
|
}
|
|
/*-----------------------------------------------------------*/
|
|
|
|
#if( configASSERT_DEFINED == 1 )
|
|
|
|
void vPortValidateInterruptPriority( void )
|
|
{
|
|
extern uint32_t ulPortGetIPSR( void );
|
|
uint32_t ulCurrentInterrupt;
|
|
uint8_t ucCurrentPriority;
|
|
|
|
ulCurrentInterrupt = ulPortGetIPSR();
|
|
|
|
/* Is the interrupt number a user defined interrupt? */
|
|
if( ulCurrentInterrupt >= portFIRST_USER_INTERRUPT_NUMBER )
|
|
{
|
|
/* Look up the interrupt's priority. */
|
|
ucCurrentPriority = pcInterruptPriorityRegisters[ 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:
|
|
http://www.freertos.org/RTOS-Cortex-M3-M4.html
|
|
http://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 unpredicable behaviour. */
|
|
configASSERT( ( portAIRCR_REG & portPRIORITY_GROUP_MASK ) <= ulMaxPRIGROUPValue );
|
|
}
|
|
|
|
#endif /* configASSERT_DEFINED */
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|