esp-idf/components/freertos/Kconfig

menu "FreeRTOS"

    menu "Kernel"
        # Upstream FreeRTOS configurations go here

        config FREERTOS_SMP
            bool "Run the Amazon SMP FreeRTOS kernel instead (FEATURE UNDER DEVELOPMENT)"
            default  "n"
            help
                Amazon has released an SMP version of the FreeRTOS Kernel which can be found via the following link:
                https://github.com/FreeRTOS/FreeRTOS-Kernel/tree/smp

                IDF has added an experimental port of this SMP kernel located in
                components/freertos/FreeRTOS-Kernel-SMP. Enabling this option will cause IDF to use the Amazon SMP
                kernel. Note that THIS FEATURE IS UNDER ACTIVE DEVELOPMENT, users use this at their own risk.

                Leaving this option disabled will mean the IDF FreeRTOS kernel is used instead, which is located in:
                components/freertos/FreeRTOS-Kernel. Both kernel versions are SMP capable, but differ in
                their implementation and features.

        config FREERTOS_UNICORE
            # Todo: Replace with CONFIG_NUM_CORES (IDF-4986)
            bool "Run FreeRTOS only on first core"
            default "y" if IDF_TARGET_ESP32S2 || IDF_TARGET_LINUX
            select ESP_SYSTEM_SINGLE_CORE_MODE
            help
                This version of FreeRTOS normally takes control of all cores of the CPU. Select this if you only want
                to start it on the first core. This is needed when e.g. another process needs complete control over the
                second core.

        config FREERTOS_HZ
            # Todo: Rename to CONFIG_FREERTOS_TICK_RATE_HZ (IDF-4986)
            int "configTICK_RATE_HZ"
            range 1 1000
            default 100
            help
                Sets the FreeRTOS tick interrupt frequency in Hz (see configTICK_RATE_HZ documentation for more
                details).

        config FREERTOS_OPTIMIZED_SCHEDULER
            # Todo: Not available in SMP FREERTOS (IDF-3733)
            bool "configUSE_PORT_OPTIMISED_TASK_SELECTION"
            depends on FREERTOS_UNICORE && !FREERTOS_SMP
            default y
            help
                Enables port specific task selection method. This option can speed up the search of ready tasks
                when scheduling (see configUSE_PORT_OPTIMISED_TASK_SELECTION documentation for more details).

        choice FREERTOS_CHECK_STACKOVERFLOW
            prompt "configCHECK_FOR_STACK_OVERFLOW"
            default FREERTOS_CHECK_STACKOVERFLOW_CANARY
            help
                Enables FreeRTOS to check for stack overflows (see configCHECK_FOR_STACK_OVERFLOW documentation for
                more details).

                Note: If users do not provide their own ``vApplicationStackOverflowHook()`` function, a default
                function will be provided by ESP-IDF.

            config FREERTOS_CHECK_STACKOVERFLOW_NONE
                bool "No checking"
                help
                    Do not check for stack overflows (configCHECK_FOR_STACK_OVERFLOW = 0)

            config FREERTOS_CHECK_STACKOVERFLOW_PTRVAL
                bool "Check by stack pointer value (Method 1)"
                help
                    Check for stack overflows on each context switch by checking if the stack pointer is in a valid
                    range. Quick but does not detect stack overflows that happened between context switches
                    (configCHECK_FOR_STACK_OVERFLOW = 1)

            config FREERTOS_CHECK_STACKOVERFLOW_CANARY
                bool "Check using canary bytes (Method 2)"
                help
                    Places some magic bytes at the end of the stack area and on each context switch, check if these
                    bytes are still intact. More thorough than just checking the pointer, but also slightly slower.
                    (configCHECK_FOR_STACK_OVERFLOW = 2)
        endchoice # FREERTOS_CHECK_STACKOVERFLOW

        config FREERTOS_THREAD_LOCAL_STORAGE_POINTERS
            int "configNUM_THREAD_LOCAL_STORAGE_POINTERS"
            range 1 256
            default 1
            help
                Set the number of thread local storage pointers in each task (see
                configNUM_THREAD_LOCAL_STORAGE_POINTERS documentation for more details).

                Note: In ESP-IDF, this value must be at least 1. Index 0 is reserved for use by the pthreads API
                thread-local-storage. Other indexes can be used for any desired purpose.

        config FREERTOS_IDLE_TASK_STACKSIZE
            int "configMINIMAL_STACK_SIZE (Idle task stack size)"
            range 768 32768
            default 1536
            help
                Sets the idle task stack size in bytes (see configMINIMAL_STACK_SIZE documentation for more details).

                Note:

                - ESP-IDF specifies stack sizes in bytes instead of words.
                - The default size is enough for most use cases.
                - The stack size may need to be increased above the default if the app installs idle or thread local
                  storage cleanup hooks that use a lot of stack memory.
                - Conversely, the stack size can be reduced to the minimum if non of the idle features are used.

        config FREERTOS_USE_IDLE_HOOK
            bool "configUSE_IDLE_HOOK"
            default n
            help
                Enables the idle task application hook (see configUSE_IDLE_HOOK documentation for more details).

                Note:

                - The application must provide the hook function ``void vApplicationIdleHook( void );``
                - ``vApplicationIdleHook()`` is called from FreeRTOS idle task(s)
                - The FreeRTOS idle hook is NOT the same as the ESP-IDF Idle Hook, but both can be enabled
                  simultaneously.

        config FREERTOS_USE_MINIMAL_IDLE_HOOK
            bool "Use FreeRTOS minimal idle hook"
            depends on FREERTOS_SMP
            default n
            help
                Enables the minimal idle task application hook (see configUSE_IDLE_HOOK documentation for more
                details).

                Note:

                - The application must provide the hook function ``void vApplicationMinimalIdleHook( void );``
                - ``vApplicationMinimalIdleHook()`` is called from FreeRTOS minimal idle task(s)

        config FREERTOS_USE_TICK_HOOK
            bool "configUSE_TICK_HOOK"
            default n
            help
                Enables the tick hook (see configUSE_TICK_HOOK documentation for more details).

                Note:

                - The application must provide the hook function ``void vApplicationTickHook( void );``
                - ``vApplicationTickHook()`` is called from FreeRTOS's tick handling function ``xTaskIncrementTick()``
                - The FreeRTOS tick hook is NOT the same as the ESP-IDF Tick Interrupt Hook, but both can be enabled
                  simultaneously.

        config FREERTOS_MAX_TASK_NAME_LEN
            int "configMAX_TASK_NAME_LEN"
            range 1 256
            default 16
            help
                Sets the maximum number of characters for task names (see configMAX_TASK_NAME_LEN documentation for
                more details).

                Note: For most uses, the default of 16 characters is sufficient.

        config FREERTOS_ENABLE_BACKWARD_COMPATIBILITY
            bool "configENABLE_BACKWARD_COMPATIBILITY"
            default n
            depends on !IDF_TARGET_LINUX
            help
                Enable backward compatibility with APIs prior to FreeRTOS v8.0.0. (see
                configENABLE_BACKWARD_COMPATIBILITY documentation for more details).

        config FREERTOS_TIMER_TASK_PRIORITY
            int "configTIMER_TASK_PRIORITY"
            range 1 25
            default 1
            help
                Sets the timer task's priority (see configTIMER_TASK_PRIORITY documentation for more details).

        config FREERTOS_TIMER_TASK_STACK_DEPTH
            int "configTIMER_TASK_STACK_DEPTH"
            range 1536 32768
            default 2053 if IDF_TARGET_LINUX
            default 2048
            help
                Set the timer task's stack size (see configTIMER_TASK_STACK_DEPTH documentation for more details).

        config FREERTOS_TIMER_QUEUE_LENGTH
            int "configTIMER_QUEUE_LENGTH"
            range 5 20
            default 10
            help
                Set the timer task's command queue length (see configTIMER_QUEUE_LENGTH documentation for more
                details).

        config FREERTOS_QUEUE_REGISTRY_SIZE
            int "configQUEUE_REGISTRY_SIZE"
            range 0 20
            default 0
            help
                Set the size of the queue registry (see configQUEUE_REGISTRY_SIZE documentation for more details).

                Note: A value of 0 will disable queue registry functionality

        config FREERTOS_TASK_NOTIFICATION_ARRAY_ENTRIES
            int "configTASK_NOTIFICATION_ARRAY_ENTRIES"
            range 1 32
            default 1
            help
                Set the size of the task notification array of each task. When increasing this value, keep in
                mind that this means additional memory for each and every task on the system.
                However, task notifications in general are more light weight compared to alternatives
                such as semaphores.

        config FREERTOS_USE_TRACE_FACILITY
            bool "configUSE_TRACE_FACILITY"
            default n
            help
                Enables additional structure members and functions to assist with execution visualization and tracing
                (see configUSE_TRACE_FACILITY documentation for more details).

        config FREERTOS_USE_STATS_FORMATTING_FUNCTIONS
            bool "configUSE_STATS_FORMATTING_FUNCTIONS"
            depends on FREERTOS_USE_TRACE_FACILITY
            default n
            help
                Set configUSE_TRACE_FACILITY and configUSE_STATS_FORMATTING_FUNCTIONS to 1 to include the
                ``vTaskList()`` and ``vTaskGetRunTimeStats()`` functions in the build (see
                configUSE_STATS_FORMATTING_FUNCTIONS documentation for more details).

        config FREERTOS_VTASKLIST_INCLUDE_COREID
            # Core affinity is supported in stats for Amazon FreeRTOS SMP by default
            bool "Enable display of xCoreID in vTaskList"
            depends on !FREERTOS_SMP && FREERTOS_USE_STATS_FORMATTING_FUNCTIONS
            default n
            help
                If enabled, this will include an extra column when vTaskList is called to display the CoreID the task
                is pinned to (0,1) or -1 if not pinned.

        config FREERTOS_GENERATE_RUN_TIME_STATS
            bool "configGENERATE_RUN_TIME_STATS"
            default n
            select FREERTOS_USE_TRACE_FACILITY
            select FREERTOS_USE_STATS_FORMATTING_FUNCTIONS
            help
                Enables collection of run time statistics for each task (see configGENERATE_RUN_TIME_STATS
                documentation for more details).

                Note: The clock used for run time statistics can be configured in FREERTOS_RUN_TIME_STATS_CLK.

        config FREERTOS_USE_TICKLESS_IDLE
            # Todo: Currently not supported in SMP FreeRTOS yet (IDF-4986)
            # Todo: Consider whether this option should still be exposed (IDF-4986)
            bool "configUSE_TICKLESS_IDLE"
            depends on PM_ENABLE
            default n
            help
                If power management support is enabled, FreeRTOS will be able to put the system into light sleep mode
                when no tasks need to run for a number of ticks. This number can be set using
                FREERTOS_IDLE_TIME_BEFORE_SLEEP option. This feature is also known as "automatic light sleep".

                Note that timers created using esp_timer APIs may prevent the system from entering sleep mode, even
                when no tasks need to run. To skip unnecessary wake-up initialize a timer with the
                "skip_unhandled_events" option as true.

                If disabled, automatic light sleep support will be disabled.

        config FREERTOS_IDLE_TIME_BEFORE_SLEEP
            # Todo: Rename to CONFIG_FREERTOS_EXPECTED_IDLE_TIME_BEFORE_SLEEP (IDF-4986)
            int "configEXPECTED_IDLE_TIME_BEFORE_SLEEP"
            depends on FREERTOS_USE_TICKLESS_IDLE
            default 3
            range 2 4294967295
            # Minimal value is 2 because of a check in FreeRTOS.h (search configEXPECTED_IDLE_TIME_BEFORE_SLEEP)
            help
                FreeRTOS will enter light sleep mode if no tasks need to run for this number of ticks.

    endmenu # Kernel

    menu "Port"
        # ESP-IDF FreeRTOS port configurations go here (and HW configurations related to FreeRTOS)

        config FREERTOS_TASK_FUNCTION_WRAPPER
            bool "Wrap task functions"
            depends on COMPILER_OPTIMIZATION_DEFAULT || ESP_COREDUMP_ENABLE || ESP_GDBSTUB_ENABLED
            default y
            help
                If enabled, all FreeRTOS task functions will be enclosed in a wrapper function. If a task function
                mistakenly returns (i.e. does not delete), the call flow will return to the wrapper function. The
                wrapper function will then log an error and abort the application. This option is also required for GDB
                backtraces and C++ exceptions to work correctly inside top-level task functions.

        config FREERTOS_WATCHPOINT_END_OF_STACK
            bool "Enable stack overflow debug watchpoint"
            default n
            help
                FreeRTOS can check if a stack has overflown its bounds by checking either the value of the stack
                pointer or by checking the integrity of canary bytes. (See FREERTOS_CHECK_STACKOVERFLOW for more
                information.) These checks only happen on a context switch, and the situation that caused the stack
                overflow may already be long gone by then. This option will use the last debug memory watchpoint to
                allow breaking into the debugger (or panic'ing) as soon as any of the last 32 bytes on the stack of a
                task are overwritten. The side effect is that using gdb, you effectively have one hardware watchpoint
                less because the last one is overwritten as soon as a task switch happens.

                Another consequence is that due to alignment requirements of the watchpoint, the usable stack size
                decreases by up to 60 bytes. This is because the watchpoint region has to be aligned to its size and
                the size for the stack watchpoint in IDF is 32 bytes.

                This check only triggers if the stack overflow writes within 32 bytes near the end of the stack, rather
                than overshooting further, so it is worth combining this approach with one of the other stack overflow
                check methods.

                When this watchpoint is hit, gdb will stop with a SIGTRAP message. When no JTAG OCD is attached,
                esp-idf will panic on an unhandled debug exception.

        config FREERTOS_TLSP_DELETION_CALLBACKS
            bool "Enable thread local storage pointers deletion callbacks"
            depends on (FREERTOS_THREAD_LOCAL_STORAGE_POINTERS > 0)
            default y
            help
                ESP-IDF provides users with the ability to free TLSP memory by registering TLSP deletion callbacks.
                These callbacks are automatically called by FreeRTOS when a task is deleted. When this option is turned
                on, the memory reserved for TLSPs in the TCB is doubled to make space for storing the deletion
                callbacks. If the user does not wish to use TLSP deletion callbacks then this option could be turned
                off to save space in the TCB memory.

        config FREERTOS_ENABLE_STATIC_TASK_CLEAN_UP
            bool "Enable static task clean up hook"
            default n
            help
                Enable this option to make FreeRTOS call the static task clean up hook when a task is deleted.

                Note: Users will need to provide a ``void vPortCleanUpTCB ( void *pxTCB )`` callback

        config FREERTOS_CHECK_MUTEX_GIVEN_BY_OWNER
            # This feature is innately supported in FreeRTOS SMP, and hence not available as a config option when
            # FreeRTOS SMP is enabled.
            depends on !FREERTOS_SMP
            bool "Check that mutex semaphore is given by owner task"
            default y
            help
                If enabled, assert that when a mutex semaphore is given, the task giving the semaphore is the task
                which is currently holding the mutex.

        config FREERTOS_ISR_STACKSIZE
            int "ISR stack size"
            range 2096 32768 if ESP_COREDUMP_DATA_FORMAT_ELF
            default 2096 if ESP_COREDUMP_DATA_FORMAT_ELF
            range 1536 32768
            default 1536
            help
                The interrupt handlers have their own stack. The size of the stack can be defined here. Each processor
                has its own stack, so the total size occupied will be twice this.

        config FREERTOS_INTERRUPT_BACKTRACE
            # Todo: Consider removing this. Not sure when users will ever want it to be disabled (IDF-4986)
            bool "Enable backtrace from interrupt to task context"
            default y
            help
                If this option is enabled, interrupt stack frame will be modified to point to the code of the
                interrupted task as its return address. This helps the debugger (or the panic handler) show a backtrace
                from the interrupt to the task which was interrupted. This also works for nested interrupts: higher
                level interrupt stack can be traced back to the lower level interrupt. This option adds 4 instructions
                to the interrupt dispatching code.

        config FREERTOS_FPU_IN_ISR
            bool "Use float in Level 1 ISR"
            depends on IDF_TARGET_ESP32
            default n
            help
                When enabled, the usage of float type is allowed inside Level 1 ISRs. Note that usage of float types in
                higher level interrupts is still not permitted.

        config FREERTOS_TICK_SUPPORT_CORETIMER
            bool
            default y if IDF_TARGET_ESP32 || IDF_TARGET_ESP32S2

        config FREERTOS_TICK_SUPPORT_SYSTIMER
            bool
            default y if !FREERTOS_TICK_SUPPORT_CORETIMER
            # All targets except ESP32 and ESP32S2 can use Systimer for FreeRTOS SysTick
            # ESP32S2 also has SYSTIMER but it can not be used for the FreeRTOS SysTick because:
            # - It has only one counter, which already in use esp_timer.
            #   A counter for SysTick should be stall in debug mode but work esp_timer.
            # - It is not possible to allocate two handlers for esp_timer and SysTick.

        choice FREERTOS_CORETIMER
            prompt "Tick timer source (Xtensa Only)"
            default FREERTOS_CORETIMER_0 if FREERTOS_TICK_SUPPORT_CORETIMER
            default FREERTOS_CORETIMER_SYSTIMER_LVL1 if FREERTOS_TICK_SUPPORT_SYSTIMER
            help
                FreeRTOS needs a timer with an associated interrupt to use as the main tick source to increase
                counters, run timers and do pre-emptive multitasking with. There are multiple timers available to do
                this, with different interrupt priorities.

            config FREERTOS_CORETIMER_0
                bool "Timer 0 (int 6, level 1)"
                depends on FREERTOS_TICK_SUPPORT_CORETIMER
                help
                    Select this to use timer 0

            config FREERTOS_CORETIMER_1
                bool "Timer 1 (int 15, level 3)"
                depends on FREERTOS_TICK_SUPPORT_CORETIMER
                help
                    Select this to use timer 1

            config FREERTOS_CORETIMER_SYSTIMER_LVL1
                bool "SYSTIMER 0 (level 1)"
                depends on FREERTOS_TICK_SUPPORT_SYSTIMER
                help
                    Select this to use systimer with the 1 interrupt priority.

            config FREERTOS_CORETIMER_SYSTIMER_LVL3
                bool "SYSTIMER 0 (level 3)"
                depends on FREERTOS_TICK_SUPPORT_SYSTIMER
                help
                    Select this to use systimer with the 3 interrupt priority.

        endchoice # FREERTOS_CORETIMER

        config FREERTOS_SYSTICK_USES_SYSTIMER
            bool
            default y if FREERTOS_CORETIMER_SYSTIMER_LVL1 || FREERTOS_CORETIMER_SYSTIMER_LVL3
            select ESP_SLEEP_SYSTIMER_STALL_WORKAROUND if IDF_TARGET_ESP32C3

        config FREERTOS_SYSTICK_USES_CCOUNT
            bool
            default y if FREERTOS_CORETIMER_0 || FREERTOS_CORETIMER_1

        choice FREERTOS_RUN_TIME_STATS_CLK
            prompt "Choose the clock source for run time stats"
            depends on FREERTOS_GENERATE_RUN_TIME_STATS
            default FREERTOS_RUN_TIME_STATS_USING_ESP_TIMER
            help
                Choose the clock source for FreeRTOS run time stats. Options are CPU0's CPU Clock or the ESP Timer.
                Both clock sources are 32 bits. The CPU Clock can run at a higher frequency hence provide a finer
                resolution but will overflow much quicker. Note that run time stats are only valid until the clock
                source overflows.

            config FREERTOS_RUN_TIME_STATS_USING_ESP_TIMER
                bool "Use ESP TIMER for run time stats"
                help
                    ESP Timer will be used as the clock source for FreeRTOS run time stats. The ESP Timer runs at a
                    frequency of 1MHz regardless of Dynamic Frequency Scaling. Therefore the ESP Timer will overflow in
                    approximately 4290 seconds.

            config FREERTOS_RUN_TIME_STATS_USING_CPU_CLK
                # Todo: This should be disabled for multi-core due to different CCOUNTs (IDF-4986)
                bool "Use CPU Clock for run time stats"
                depends on FREERTOS_SYSTICK_USES_CCOUNT
                help
                    CPU Clock will be used as the clock source for the generation of run time stats. The CPU Clock has
                    a frequency dependent on ESP_DEFAULT_CPU_FREQ_MHZ and Dynamic Frequency Scaling (DFS). Therefore
                    the CPU Clock frequency can fluctuate between 80 to 240MHz. Run time stats generated using the CPU
                    Clock represents the number of CPU cycles each task is allocated and DOES NOT reflect the amount of
                    time each task runs for (as CPU clock frequency can change). If the CPU clock consistently runs at
                    the maximum frequency of 240MHz, it will overflow in approximately 17 seconds.
        endchoice # FREERTOS_RUN_TIME_STATS_CLK

        config FREERTOS_PLACE_FUNCTIONS_INTO_FLASH
            bool "Place FreeRTOS functions into Flash"
            default n
            help
                When enabled the selected Non-ISR FreeRTOS functions will be placed into Flash memory instead of IRAM.
                This saves up to 8KB of IRAM depending on which functions are used.

        config FREERTOS_PLACE_SNAPSHOT_FUNS_INTO_FLASH
            bool "Place task snapshot functions into flash"
            default n
            depends on FREERTOS_ENABLE_TASK_SNAPSHOT && !ESP_PANIC_HANDLER_IRAM
            help
                When enabled, the functions related to snapshots, such as vTaskGetSnapshot or uxTaskGetSnapshotAll,
                will be placed in flash. Note that if enabled, these functions cannot be called when cache is disabled.

        config FREERTOS_CHECK_PORT_CRITICAL_COMPLIANCE
            # Todo: Check if we still need this (IDF-4986)
            bool "Tests compliance with Vanilla FreeRTOS port*_CRITICAL calls"
            default n
            help
                If enabled, context of port*_CRITICAL calls (ISR or Non-ISR) would be checked to be in compliance with
                Vanilla FreeRTOS. e.g Calling port*_CRITICAL from ISR context would cause assert failure

        config FREERTOS_ENABLE_TASK_SNAPSHOT
            bool "Enable task snapshot functions"
            default y
            help
                When enabled, the functions related to snapshots, such as vTaskGetSnapshot or uxTaskGetSnapshotAll, are
                compiled and linked. Task snapshots are used by Task Watchdog (TWDT), GDB Stub and Core dump.

    endmenu # Port

    # Hidden or compatibility options

    config FREERTOS_PORT
        # This invisible config value indicates the FreeRTOS is selected as the current RTOS used by ESP-IDF
        bool
        default y

    config FREERTOS_NO_AFFINITY
        # This invisible config value sets the value of tskNO_AFFINITY in task.h.
        # Intended to be used as a constant from other Kconfig files.
        # Value is (32-bit) INT_MAX.
        hex
        default 0x7FFFFFFF if !FREERTOS_SMP
        default 0xFFFFFFFF if FREERTOS_SMP

    config FREERTOS_SUPPORT_STATIC_ALLOCATION
        # Always enabled. Kconfig option preserved for compatibility with code which checked for
        # CONFIG_FREERTOS_SUPPORT_STATIC_ALLOCATION.
        # Todo: Check if we still need this (IDF-4986)
        bool
        default y

    config FREERTOS_DEBUG_OCDAWARE
        bool
        help
            Hidden option, gets selected by CONFIG_ESP_DEBUG_OCDAWARE

endmenu # FreeRTOS