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Make CM3/4 tick configuration a weak function to allow application writers to use an alternative tick source.

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This commit is contained in:
Richard Barry 2012-10-29 15:56:26 +00:00
parent 5e7c99d2aa
commit ba686260ca
9 changed files with 338 additions and 214 deletions
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84
FreeRTOS/Source/portable/RVDS/ARM_CM4F/port.c
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@ -84,15 +84,16 @@
#ifndef configSYSTICK_CLOCK_HZ
#define configSYSTICK_CLOCK_HZ configCPU_CLOCK_HZ
#if configUSE_TICKLESS_IDLE == 1
static const unsigned long ulStoppedTimerCompensation = 45UL;
#endif
#else /* configSYSTICK_CLOCK_HZ */
#if configUSE_TICKLESS_IDLE == 1
/* Assumes the SysTick clock is slower than the CPU clock. */
static const unsigned long ulStoppedTimerCompensation = 45UL / ( configCPU_CLOCK_HZ / configSYSTICK_CLOCK_HZ );
#endif
#endif /* configSYSTICK_CLOCK_HZ */
#endif
/* The __weak attribute does not work as you might expect with the Keil tools
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
/* Constants required to manipulate the core. Registers first... */
#define portNVIC_SYSTICK_CTRL_REG ( * ( ( volatile unsigned long * ) 0xe000e010 ) )
@ -125,9 +126,11 @@ variable. */
static unsigned portBASE_TYPE uxCriticalNesting = 0xaaaaaaaa;
/*
* Setup the timer to generate the tick interrupts.
* 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.
*/
static void prvSetupTimerInterrupt( void );
void vPortSetupTimerInterrupt( void );
/*
* Exception handlers.
@ -150,7 +153,9 @@ static void prvEnableVFP( void );
/*
* The number of SysTick increments that make up one tick period.
*/
static unsigned long ulTimerReloadValueForOneTick = 0;
#if configUSE_TICKLESS_IDLE == 1
static unsigned long ulTimerReloadValueForOneTick = 0;
#endif
/*
* The maximum number of tick periods that can be suppressed is limited by the
@ -160,6 +165,14 @@ static unsigned long ulTimerReloadValueForOneTick = 0;
static unsigned long 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 unsigned long ulStoppedTimerCompensation = 0;
#endif /* configUSE_TICKLESS_IDLE */
/*-----------------------------------------------------------*/
/*
@ -257,7 +270,7 @@ portBASE_TYPE xPortStartScheduler( void )
/* Start the timer that generates the tick ISR. Interrupts are disabled
here already. */
prvSetupTimerInterrupt();
vPortSetupTimerInterrupt();
/* Initialise the critical nesting count ready for the first task. */
uxCriticalNesting = 0;
@ -368,6 +381,10 @@ void xPortSysTickHandler( void )
}
#endif
/* Only reset the systick load register if configUSE_TICKLESS_IDLE is set to
1. If it is set to 0 tickless idle is not being used. If it is set to a
value other than 0 or 1 then a timer other than the SysTick is being used
to generate the tick interrupt. */
#if configUSE_TICKLESS_IDLE == 1
portNVIC_SYSTICK_LOAD_REG = ulTimerReloadValueForOneTick;
#endif
@ -431,9 +448,12 @@ void xPortSysTickHandler( void )
portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
/* Sleep until something happens. */
configPRE_SLEEP_PROCESSING();
__wfi();
configPOST_SLEEP_PROCESSING();
configPRE_SLEEP_PROCESSING( xExpectedIdleTime );
if( xExpectedIdleTime > 0 )
{
__wfi();
}
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
@ -486,21 +506,28 @@ void xPortSysTickHandler( void )
/*-----------------------------------------------------------*/
/*
* Setup the systick timer to generate the tick interrupts at the required
* Setup the SysTick timer to generate the tick interrupts at the required
* frequency.
*/
void prvSetupTimerInterrupt( void )
{
/* Calculate the constants required to configure the tick interrupt. */
ulTimerReloadValueForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;
#if configUSE_TICKLESS_IDLE == 1
xMaximumPossibleSuppressedTicks = 0xffffffUL / ( ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL );
#endif /* configUSE_TICKLESS_IDLE */
#if configOVERRIDE_DEFAULT_TICK_CONFIGURATION == 0
/* Configure SysTick to interrupt at the requested rate. */
portNVIC_SYSTICK_LOAD_REG = ulTimerReloadValueForOneTick;
portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT;
}
void vPortSetupTimerInterrupt( void )
{
/* Calculate the constants required to configure the tick interrupt. */
#if configUSE_TICKLESS_IDLE == 1
{
ulTimerReloadValueForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;
xMaximumPossibleSuppressedTicks = 0xffffffUL / ( ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL );
ulStoppedTimerCompensation = 45UL / ( configCPU_CLOCK_HZ / configSYSTICK_CLOCK_HZ );
}
#endif /* configUSE_TICKLESS_IDLE */
/* 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 */
/*-----------------------------------------------------------*/
__asm unsigned long ulPortSetInterruptMask( void )
@ -512,7 +539,6 @@ __asm unsigned long ulPortSetInterruptMask( void )
msr basepri, r1
bx r14
}
/*-----------------------------------------------------------*/
__asm void vPortClearInterruptMask( unsigned long ulNewMask )