ec80ab5bb6
Makes the choice CORTEX_M_SYSTICK_LPM dependent upon the CORTEX_M_SYSTICK to prevent its default from showing up in the .config of projects that do not use the CORTEX_M_SYSTICK timer driver. Signed-off-by: Peter Mitsis <peter.mitsis@intel.com>
113 lines
4.4 KiB
Plaintext
113 lines
4.4 KiB
Plaintext
# Copyright (c) 2014-2015 Wind River Systems, Inc.
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# Copyright (c) 2016 Cadence Design Systems, Inc.
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# Copyright (c) 2019 Intel Corp.
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# SPDX-License-Identifier: Apache-2.0
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DT_CHOSEN_IDLE_TIMER := zephyr,cortex-m-idle-timer
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config CORTEX_M_SYSTICK
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bool "Cortex-M SYSTICK timer"
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depends on CPU_CORTEX_M_HAS_SYSTICK
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default y
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depends on DT_HAS_ARM_ARMV6M_SYSTICK_ENABLED || \
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DT_HAS_ARM_ARMV7M_SYSTICK_ENABLED || \
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DT_HAS_ARM_ARMV8M_SYSTICK_ENABLED || \
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DT_HAS_ARM_ARMV8_1M_SYSTICK_ENABLED
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select TICKLESS_CAPABLE
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select SYSTEM_TIMER_HAS_DISABLE_SUPPORT
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select CORTEX_M_SYSTICK_INSTALL_ISR
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help
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This module implements a kernel device driver for the Cortex-M processor
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SYSTICK timer and provides the standard "system clock driver" interfaces.
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config CORTEX_M_SYSTICK_INSTALL_ISR
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bool
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depends on CPU_CORTEX_M_HAS_SYSTICK
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help
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This option should be selected by SysTick-based drivers so that the
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sys_clock_isr() function is installed.
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config CORTEX_M_SYSTICK_64BIT_CYCLE_COUNTER
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bool "Cortex-M SYSTICK timer with sys_clock_cycle_get_64() support"
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depends on CORTEX_M_SYSTICK
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default y if (SYS_CLOCK_HW_CYCLES_PER_SEC > 60000000)
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select TIMER_HAS_64BIT_CYCLE_COUNTER
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help
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This driver, due to its limited 24-bits hardware counter, is already
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tracking a separate cycle count in software. This option make that
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count a 64-bits value to support sys_clock_cycle_get_64().
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This is cheap to do as expensive math operations (i.e. divisions)
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are performed only on counter interval values that always fit in
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32 bits.
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This is set to y by default when the hardware clock is fast enough
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to wrap sys_clock_cycle_get_32() in about a minute or less.
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choice CORTEX_M_SYSTICK_LPM_TIMER
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prompt "SysTick companion low-power mode timer"
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depends on CORTEX_M_SYSTICK
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# If all dependencies are enabled, and /chosen/cortex-m-idle-timer
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# is enabled, default to using the Counter API-based LPM timer.
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# Otherwise, the first choice (LPM_TIMER_NONE) will be selected
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# automatically, and no LPM timer will be enabled.
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default CORTEX_M_SYSTICK_LPM_TIMER_COUNTER
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help
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It is common for SoCs equipped with SysTick to use it as system timer.
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However, depending on the SoC implementation, entering low-power mode
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may turn off the SysTick clock or place SysTick under reset.
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On such SoCs, a vendor-specific timer that remains active in low-power
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mode will usually be provided - however, it may be unfit for usage as
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system timer, for example because its frequency is too low.
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With this option, such vendor-specific timer can be selected and used by
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the SysTick driver to ensure proper system operation in low-power mode.
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NOTE: since Power Management has to be enabled if the SoC may enter in
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low-power mode, no LPM timer can be selected if PM is not enabled.
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Tickless kernel must also be enabled, since periodic interrupts would
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prevent the system from entering in low-power modes.
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config CORTEX_M_SYSTICK_LPM_TIMER_NONE
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bool "None"
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help
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Use no additional device as low-power mode timer.
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The SoC must never enter a low-power mode where SysTick is disabled when
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this option is selected; otherwise, system behavior becomes unpredictable.
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if TICKLESS_KERNEL && PM
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config CORTEX_M_SYSTICK_LPM_TIMER_COUNTER
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bool "Counter API timer"
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depends on $(dt_chosen_enabled,$(DT_CHOSEN_IDLE_TIMER))
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depends on COUNTER
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help
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Use a device that implements the counter API as low-power mode timer.
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The device is selected by property "/chosen/cortex-m-idle-timer".
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config CORTEX_M_SYSTICK_LPM_TIMER_HOOKS
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bool "Hook-based timer"
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help
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Use hooks in the SysTick driver to configure the low-power mode timer.
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Refer to `include/drivers/timer/cortex_m_systick.h` for more details.
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endif # PM
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endchoice # CORTEX_M_SYSTICK_LPM_TIMER
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config CORTEX_M_SYSTICK_RESET_BY_LPM
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bool
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depends on !CORTEX_M_SYSTICK_LPM_TIMER_NONE
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help
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Some SoCs provide one or more low-power mode which, as part of their
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operation, place SysTick or the entire CPU under reset. This requires
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special care from the driver - notably, SysTick needs to be restarted
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after waking up from such a low-power mode.
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Select this symbol if your SoC has a low-power mode that places SysTick
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under reset. Note that this requires that the platform provides a timer
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active in low-power mode, since SysTick cannot be used for timekeeping.
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Refer to CONFIG_CORTEX_M_SYSTICK_LPM_TIMER for more details.
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