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FreeRTOS-Kernel/include
Jeff Tenney 990643ebe8
Fix support for stepping tick by xExpectedIdleTime (#73)
* Fix support for stepping maximum number of ticks

This commit fixes support for tickless implementations that call
vTaskStepTick() with the maximum number of allowed ticks to step.

vTaskStepTick()
---------------
Function vTaskStepTick() provides a way for the tickless idle
implementation to account for ticks that elapse during tickless idle.
The maximum number of stepped ticks allowed is the number passed to
portSUPPRESS_TICKS_AND_SLEEP().  It is the number of ticks between
xTickCount and xNextTaskUnblockTime.

vTaskStepTick() is specifically intended for use with tickless idle,
so it always executes with the scheduler disabled.  For reference,
compare it with the more general function xTaskCatchUpTicks().

Without this Change
-------------------
Prior to this commit, if a task is supposed to wake at xTickCount ==
0xFFFFFFFF, then when tickless idle ends, function vTaskStepTick()
sets the tick to 0xFFFFFFFF but the task remains on the delayed list
because xTaskIncrementTick() does not execute.  One tick later,
xTaskIncrementTick() executes because it's time to increment xTickCount
to 0x00000000.  An assertion failure occurs in
taskSWITCH_DELAYED_LISTS() because the delayed task list is not
empty.  Other examples of valling vTaskStepTick() with the maximum
allowed number of ticks merely result in a task waking one tick late.

Default Tickless Implementations
--------------------------------
Note that the default tickless implementations never pass the maximum
allowed value to vTaskStepTick().  The default implementations use the
tick interrupt to finish the sleep and allow that one tick to be
counted normally via the tick ISR and xTaskIncrementTick().

* Protect xPendedTicks with critical section

Function xTaskIncrementTick() increments xPendedTicks when the
scheduler is disabled.  That function typically executes inside the tick
ISR.  So code in xTaskCatchUpTicks() must mask interrupts when modifying
xPendedTicks.

* uncrustify tasks.c

* Update tasks.c

Style changes only - added comment and indentation to the two modified files.

* uncrustify

* Add test coverage for new conditional

* Add typecast

Co-authored-by: Cobus van Eeden <35851496+cobusve@users.noreply.github.com>
Co-authored-by: Joseph Julicher <jjulicher@mac.com>
Co-authored-by: RichardBarry <3073890+RichardBarry@users.noreply.github.com>
3 years ago
..
FreeRTOS.h Remove tickless idle mode dependency with include v task suspend (#422) 3 years ago
StackMacros.h Normalize files with mixed line endings (introduced in commit 3a413d1) 4 years ago
atomic.h Normalize files with mixed line endings (introduced in commit 3a413d1) 4 years ago
croutine.h Replace <pre> with @code - remaining files (#388) 4 years ago
deprecated_definitions.h Normalize files with mixed line endings (introduced in commit 3a413d1) 4 years ago
event_groups.h Documentation update for xEventGroupClearBitsFromISR (#432) 3 years ago
list.h Run uncrustify with github workflows (#369) 4 years ago
message_buffer.h Clean some spell check words. (#439) 3 years ago
mpu_prototypes.h Run uncrustify with github workflows (#369) 4 years ago
mpu_wrappers.h Fix formatting error 3 years ago
portable.h Run uncrustify with github workflows (#369) 4 years ago
projdefs.h Normalize files with mixed line endings (introduced in commit 3a413d1) 4 years ago
queue.h Clean some spell check words. (#439) 3 years ago
semphr.h Clean some spell check words. (#439) 3 years ago
stack_macros.h Run uncrustify with github workflows (#369) 4 years ago
stdint.readme Normalize files with mixed line endings (introduced in commit 3a413d1) 4 years ago
stream_buffer.h Clean some spell check words. (#439) 3 years ago
task.h Fix support for stepping tick by xExpectedIdleTime (#73) 3 years ago
timers.h Clean some spell check words. (#439) 3 years ago