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718 lines
27 KiB
C
718 lines
27 KiB
C
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/*
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* FreeRTOS Kernel V10.0.1
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* Copyright (C) 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of
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* this software and associated documentation files (the "Software"), to deal in
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* the Software without restriction, including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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* the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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* http://www.FreeRTOS.org
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* http://aws.amazon.com/freertos
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*
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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 CM3 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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/* For backward compatibility, ensure configKERNEL_INTERRUPT_PRIORITY is
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defined. The value should also ensure backward compatibility.
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FreeRTOS.org versions prior to V4.4.0 did not include this definition. */
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#ifndef configKERNEL_INTERRUPT_PRIORITY
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#define configKERNEL_INTERRUPT_PRIORITY 255
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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 set up the initial stack. */
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#define portINITIAL_XPSR ( 0x01000000UL )
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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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/* Let the user override the pre-loading of the initial LR with the address of
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prvTaskExitError() in case it messes up unwinding of the stack in the
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debugger. */
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#ifdef configTASK_RETURN_ADDRESS
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#define portTASK_RETURN_ADDRESS configTASK_RETURN_ADDRESS
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#else
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#define portTASK_RETURN_ADDRESS prvTaskExitError
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#endif
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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 xPortPendSVHandler( void ) __attribute__ (( naked ));
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void xPortSysTickHandler( void );
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void vPortSVCHandler( void ) __attribute__ (( naked ));
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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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static void prvPortStartFirstTask( void ) __attribute__ (( naked ));
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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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/* 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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* 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 = ( const volatile uint8_t * const ) 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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pxTopOfStack--; /* Offset added to account for the way the MCU uses the stack on entry/exit of interrupts. */
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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 ) portTASK_RETURN_ADDRESS; /* LR */
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pxTopOfStack -= 5; /* R12, R3, R2 and R1. */
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*pxTopOfStack = ( StackType_t ) pvParameters; /* R0 */
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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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volatile uint32_t ulDummy = 0UL;
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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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while( ulDummy == 0 )
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{
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/* This file calls prvTaskExitError() after the scheduler has been
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started to remove a compiler warning about the function being defined
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but never called. ulDummy is used purely to quieten other warnings
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about code appearing after this function is called - making ulDummy
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volatile makes the compiler think the function could return and
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therefore not output an 'unreachable code' warning for code that appears
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after it. */
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}
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}
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/*-----------------------------------------------------------*/
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void vPortSVCHandler( void )
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{
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__asm volatile (
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" ldr r3, pxCurrentTCBConst2 \n" /* Restore the context. */
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" ldr r1, [r3] \n" /* Use pxCurrentTCBConst to get the pxCurrentTCB address. */
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" ldr r0, [r1] \n" /* The first item in pxCurrentTCB is the task top of stack. */
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" ldmia r0!, {r4-r11} \n" /* Pop the registers that are not automatically saved on exception entry and the critical nesting count. */
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" msr psp, r0 \n" /* Restore the task stack pointer. */
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" isb \n"
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" mov r0, #0 \n"
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" msr basepri, r0 \n"
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" orr r14, #0xd \n"
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" bx r14 \n"
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" \n"
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" .align 4 \n"
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"pxCurrentTCBConst2: .word pxCurrentTCB \n"
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);
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}
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/*-----------------------------------------------------------*/
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static void prvPortStartFirstTask( void )
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{
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__asm volatile(
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" ldr r0, =0xE000ED08 \n" /* Use the NVIC offset register to locate the stack. */
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" ldr r0, [r0] \n"
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" ldr r0, [r0] \n"
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" msr msp, r0 \n" /* Set the msp back to the start of the stack. */
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" cpsie i \n" /* Globally enable interrupts. */
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" cpsie f \n"
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" dsb \n"
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" isb \n"
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" svc 0 \n" /* System call to start first task. */
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" nop \n"
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);
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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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/* configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to 0.
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See http://www.FreeRTOS.org/RTOS-Cortex-M3-M4.html */
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configASSERT( configMAX_SYSCALL_INTERRUPT_PRIORITY );
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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 = ( volatile uint8_t * const ) ( 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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#ifdef __NVIC_PRIO_BITS
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{
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/* Check the CMSIS configuration that defines the number of
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priority bits matches the number of priority bits actually queried
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from the hardware. */
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configASSERT( ( portMAX_PRIGROUP_BITS - ulMaxPRIGROUPValue ) == __NVIC_PRIO_BITS );
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}
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#endif
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#ifdef configPRIO_BITS
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{
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/* Check the FreeRTOS configuration that defines the number of
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priority bits matches the number of priority bits actually queried
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from the hardware. */
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configASSERT( ( portMAX_PRIGROUP_BITS - ulMaxPRIGROUPValue ) == configPRIO_BITS );
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}
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#endif
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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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/* Start the first task. */
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prvPortStartFirstTask();
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/* Should never get here as the tasks will now be executing! Call the task
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exit error function to prevent compiler warnings about a static function
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not being called in the case that the application writer overrides this
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functionality by defining configTASK_RETURN_ADDRESS. Call
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vTaskSwitchContext() so link time optimisation does not remove the
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symbol. */
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vTaskSwitchContext();
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prvTaskExitError();
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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 xPortPendSVHandler( void )
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{
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/* This is a naked function. */
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__asm volatile
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(
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" mrs r0, psp \n"
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" isb \n"
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" \n"
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||
|
" ldr r3, pxCurrentTCBConst \n" /* Get the location of the current TCB. */
|
||
|
" ldr r2, [r3] \n"
|
||
|
" \n"
|
||
|
" stmdb r0!, {r4-r11} \n" /* Save the remaining registers. */
|
||
|
" str r0, [r2] \n" /* Save the new top of stack into the first member of the TCB. */
|
||
|
" \n"
|
||
|
" stmdb sp!, {r3, r14} \n"
|
||
|
" mov r0, %0 \n"
|
||
|
" msr basepri, r0 \n"
|
||
|
" bl vTaskSwitchContext \n"
|
||
|
" mov r0, #0 \n"
|
||
|
" msr basepri, r0 \n"
|
||
|
" ldmia sp!, {r3, r14} \n"
|
||
|
" \n" /* Restore the context, including the critical nesting count. */
|
||
|
" ldr r1, [r3] \n"
|
||
|
" ldr r0, [r1] \n" /* The first item in pxCurrentTCB is the task top of stack. */
|
||
|
" ldmia r0!, {r4-r11} \n" /* Pop the registers. */
|
||
|
" msr psp, r0 \n"
|
||
|
" isb \n"
|
||
|
" bx r14 \n"
|
||
|
" \n"
|
||
|
" .align 4 \n"
|
||
|
"pxCurrentTCBConst: .word pxCurrentTCB \n"
|
||
|
::"i"(configMAX_SYSCALL_INTERRUPT_PRIORITY)
|
||
|
);
|
||
|
}
|
||
|
/*-----------------------------------------------------------*/
|
||
|
|
||
|
void xPortSysTickHandler( void )
|
||
|
{
|
||
|
/* 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. */
|
||
|
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 )
|
||
|
|
||
|
__attribute__((weak)) void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime )
|
||
|
{
|
||
|
uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements;
|
||
|
TickType_t xModifiableIdleTime;
|
||
|
|
||
|
/* Make sure the SysTick reload value does not overflow the counter. */
|
||
|
if( xExpectedIdleTime > xMaximumPossibleSuppressedTicks )
|
||
|
{
|
||
|
xExpectedIdleTime = xMaximumPossibleSuppressedTicks;
|
||
|
}
|
||
|
|
||
|
/* Stop the SysTick momentarily. The time the SysTick is stopped for
|
||
|
is accounted for as best it can be, but using the tickless mode will
|
||
|
inevitably result in some tiny drift of the time maintained by the
|
||
|
kernel with respect to calendar time. */
|
||
|
portNVIC_SYSTICK_CTRL_REG &= ~portNVIC_SYSTICK_ENABLE_BIT;
|
||
|
|
||
|
/* Calculate the reload value required to wait xExpectedIdleTime
|
||
|
tick periods. -1 is used because this code will execute part way
|
||
|
through one of the tick periods. */
|
||
|
ulReloadValue = portNVIC_SYSTICK_CURRENT_VALUE_REG + ( ulTimerCountsForOneTick * ( xExpectedIdleTime - 1UL ) );
|
||
|
if( ulReloadValue > ulStoppedTimerCompensation )
|
||
|
{
|
||
|
ulReloadValue -= ulStoppedTimerCompensation;
|
||
|
}
|
||
|
|
||
|
/* Enter a critical section but don't use the taskENTER_CRITICAL()
|
||
|
method as that will mask interrupts that should exit sleep mode. */
|
||
|
__asm volatile( "cpsid i" ::: "memory" );
|
||
|
__asm volatile( "dsb" );
|
||
|
__asm volatile( "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 volatile( "cpsie i" ::: "memory" );
|
||
|
}
|
||
|
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 volatile( "dsb" ::: "memory" );
|
||
|
__asm volatile( "wfi" );
|
||
|
__asm volatile( "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 volatile( "cpsie i" ::: "memory" );
|
||
|
__asm volatile( "dsb" );
|
||
|
__asm volatile( "isb" );
|
||
|
|
||
|
/* Disable interrupts again because the clock is about to be stopped
|
||
|
and interrupts that execute while the clock is stopped will increase
|
||
|
any slippage between the time maintained by the RTOS and calendar
|
||
|
time. */
|
||
|
__asm volatile( "cpsid i" ::: "memory" );
|
||
|
__asm volatile( "dsb" );
|
||
|
__asm volatile( "isb" );
|
||
|
|
||
|
/* Disable the SysTick clock without reading the
|
||
|
portNVIC_SYSTICK_CTRL_REG register to ensure the
|
||
|
portNVIC_SYSTICK_COUNT_FLAG_BIT is not cleared if it is set. Again,
|
||
|
the time the SysTick is stopped for is accounted for as best it can
|
||
|
be, but using the tickless mode will inevitably result in some tiny
|
||
|
drift of the time maintained by the kernel with respect to calendar
|
||
|
time*/
|
||
|
portNVIC_SYSTICK_CTRL_REG = ( portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT );
|
||
|
|
||
|
/* Determine if the SysTick clock has already counted to zero and
|
||
|
been set back to the current reload value (the reload back being
|
||
|
correct for the entire expected idle time) or if the SysTick is yet
|
||
|
to count to zero (in which case an interrupt other than the SysTick
|
||
|
must have brought the system out of sleep mode). */
|
||
|
if( ( portNVIC_SYSTICK_CTRL_REG & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 )
|
||
|
{
|
||
|
uint32_t ulCalculatedLoadValue;
|
||
|
|
||
|
/* The tick interrupt is already pending, and the SysTick count
|
||
|
reloaded with ulReloadValue. Reset the
|
||
|
portNVIC_SYSTICK_LOAD_REG with whatever remains of this tick
|
||
|
period. */
|
||
|
ulCalculatedLoadValue = ( ulTimerCountsForOneTick - 1UL ) - ( ulReloadValue - portNVIC_SYSTICK_CURRENT_VALUE_REG );
|
||
|
|
||
|
/* Don't allow a tiny value, or values that have somehow
|
||
|
underflowed because the post sleep hook did something
|
||
|
that took too long. */
|
||
|
if( ( ulCalculatedLoadValue < ulStoppedTimerCompensation ) || ( ulCalculatedLoadValue > ulTimerCountsForOneTick ) )
|
||
|
{
|
||
|
ulCalculatedLoadValue = ( ulTimerCountsForOneTick - 1UL );
|
||
|
}
|
||
|
|
||
|
portNVIC_SYSTICK_LOAD_REG = ulCalculatedLoadValue;
|
||
|
|
||
|
/* As the pending tick will be processed as soon as this
|
||
|
function exits, the tick value maintained by the tick is stepped
|
||
|
forward by one less than the time spent waiting. */
|
||
|
ulCompleteTickPeriods = xExpectedIdleTime - 1UL;
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
/* Something other than the tick interrupt ended the sleep.
|
||
|
Work out how long the sleep lasted rounded to complete tick
|
||
|
periods (not the ulReload value which accounted for part
|
||
|
ticks). */
|
||
|
ulCompletedSysTickDecrements = ( xExpectedIdleTime * ulTimerCountsForOneTick ) - portNVIC_SYSTICK_CURRENT_VALUE_REG;
|
||
|
|
||
|
/* How many complete tick periods passed while the processor
|
||
|
was waiting? */
|
||
|
ulCompleteTickPeriods = ulCompletedSysTickDecrements / ulTimerCountsForOneTick;
|
||
|
|
||
|
/* The reload value is set to whatever fraction of a single tick
|
||
|
period remains. */
|
||
|
portNVIC_SYSTICK_LOAD_REG = ( ( ulCompleteTickPeriods + 1UL ) * ulTimerCountsForOneTick ) - ulCompletedSysTickDecrements;
|
||
|
}
|
||
|
|
||
|
/* Restart SysTick so it runs from portNVIC_SYSTICK_LOAD_REG
|
||
|
again, then set portNVIC_SYSTICK_LOAD_REG back to its standard
|
||
|
value. */
|
||
|
portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;
|
||
|
portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT;
|
||
|
vTaskStepTick( ulCompleteTickPeriods );
|
||
|
portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL;
|
||
|
|
||
|
/* Exit with interrpts enabled. */
|
||
|
__asm volatile( "cpsie i" ::: "memory" );
|
||
|
}
|
||
|
}
|
||
|
|
||
|
#endif /* configUSE_TICKLESS_IDLE */
|
||
|
/*-----------------------------------------------------------*/
|
||
|
|
||
|
/*
|
||
|
* Setup the systick timer to generate the tick interrupts at the required
|
||
|
* frequency.
|
||
|
*/
|
||
|
__attribute__(( weak )) 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 )
|
||
|
{
|
||
|
uint32_t ulCurrentInterrupt;
|
||
|
uint8_t ucCurrentPriority;
|
||
|
|
||
|
/* Obtain the number of the currently executing interrupt. */
|
||
|
__asm volatile( "mrs %0, ipsr" : "=r"( ulCurrentInterrupt ) :: "memory" );
|
||
|
|
||
|
/* 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 unpredictable behaviour. */
|
||
|
configASSERT( ( portAIRCR_REG & portPRIORITY_GROUP_MASK ) <= ulMaxPRIGROUPValue );
|
||
|
}
|
||
|
|
||
|
#endif /* configASSERT_DEFINED */
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
|