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Add some defensive programming in the default tickless mode in case the application supplied post tick hook takes a long time to complete.

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This commit is contained in:
Richard Barry 2013-10-08 12:33:46 +00:00
parent aedf7824cb
commit 0c56f5018d
6 changed files with 106 additions and 7 deletions
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14
FreeRTOS/Source/portable/GCC/ARM_CM3/port.c
View file

@ -547,12 +547,24 @@ void xPortSysTickHandler( void )
if( ( portNVIC_SYSTICK_CTRL_REG & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 )
{
unsigned long 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. */
portNVIC_SYSTICK_LOAD_REG = ( ulTimerCountsForOneTick - 1UL ) - ( ulReloadValue - portNVIC_SYSTICK_CURRENT_VALUE_REG );
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

14
FreeRTOS/Source/portable/GCC/ARM_CM4F/port.c
View file

@ -590,12 +590,24 @@ void xPortSysTickHandler( void )
if( ( portNVIC_SYSTICK_CTRL_REG & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 )
{
unsigned long 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. */
portNVIC_SYSTICK_LOAD_REG = ( ulTimerCountsForOneTick - 1UL ) - ( ulReloadValue - portNVIC_SYSTICK_CURRENT_VALUE_REG );
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