166 lines
4.0 KiB
C
166 lines
4.0 KiB
C
/*
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* Copyright (c) 2016 Wind River Systems, Inc.
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <kernel.h>
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#include <kernel_structs.h>
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#include <toolchain.h>
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#include <linker/sections.h>
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#include <drivers/timer/system_timer.h>
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#include <wait_q.h>
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#include <power/power.h>
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#include <stdbool.h>
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#ifdef CONFIG_TICKLESS_IDLE_THRESH
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#define IDLE_THRESH CONFIG_TICKLESS_IDLE_THRESH
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#else
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#define IDLE_THRESH 1
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#endif
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/* Fallback idle spin loop for SMP platforms without a working IPI */
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#if (defined(CONFIG_SMP) && !defined(CONFIG_SCHED_IPI_SUPPORTED))
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#define SMP_FALLBACK 1
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#else
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#define SMP_FALLBACK 0
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#endif
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#ifdef CONFIG_SYS_POWER_MANAGEMENT
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/*
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* Used to allow _sys_suspend() implementation to control notification
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* of the event that caused exit from kernel idling after pm operations.
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*/
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unsigned char sys_pm_idle_exit_notify;
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/* LCOV_EXCL_START
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* These are almost certainly overidden and in any event do nothing
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*/
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#if defined(CONFIG_SYS_POWER_SLEEP_STATES)
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void __attribute__((weak)) _sys_resume(void)
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{
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}
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#endif
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#if defined(CONFIG_SYS_POWER_DEEP_SLEEP_STATES)
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void __attribute__((weak)) _sys_resume_from_deep_sleep(void)
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{
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}
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#endif
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/* LCOV_EXCL_STOP */
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#endif /* CONFIG_SYS_POWER_MANAGEMENT */
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/**
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*
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* @brief Indicate that kernel is idling in tickless mode
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*
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* Sets the kernel data structure idle field to either a positive value or
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* K_FOREVER.
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*
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* @param ticks the number of ticks to idle
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*
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* @return N/A
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*/
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#if !SMP_FALLBACK
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static void set_kernel_idle_time_in_ticks(s32_t ticks)
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{
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#ifdef CONFIG_SYS_POWER_MANAGEMENT
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_kernel.idle = ticks;
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#endif
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}
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static void sys_power_save_idle(void)
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{
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s32_t ticks = z_get_next_timeout_expiry();
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/* The documented behavior of CONFIG_TICKLESS_IDLE_THRESH is
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* that the system should not enter a tickless idle for
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* periods less than that. This seems... silly, given that it
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* saves no power and does not improve latency. But it's an
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* API we need to honor...
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*/
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#ifdef CONFIG_SYS_CLOCK_EXISTS
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z_set_timeout_expiry((ticks < IDLE_THRESH) ? 1 : ticks, true);
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#endif
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set_kernel_idle_time_in_ticks(ticks);
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#if (defined(CONFIG_SYS_POWER_SLEEP_STATES) || \
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defined(CONFIG_SYS_POWER_DEEP_SLEEP_STATES))
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sys_pm_idle_exit_notify = 1U;
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/*
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* Call the suspend hook function of the soc interface to allow
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* entry into a low power state. The function returns
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* SYS_POWER_STATE_ACTIVE if low power state was not entered, in which
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* case, kernel does normal idle processing.
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*
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* This function is entered with interrupts disabled. If a low power
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* state was entered, then the hook function should enable inerrupts
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* before exiting. This is because the kernel does not do its own idle
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* processing in those cases i.e. skips k_cpu_idle(). The kernel's
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* idle processing re-enables interrupts which is essential for
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* the kernel's scheduling logic.
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*/
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if (_sys_suspend(ticks) == SYS_POWER_STATE_ACTIVE) {
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sys_pm_idle_exit_notify = 0U;
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k_cpu_idle();
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}
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#else
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k_cpu_idle();
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#endif
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}
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#endif
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void z_sys_power_save_idle_exit(s32_t ticks)
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{
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#if defined(CONFIG_SYS_POWER_SLEEP_STATES)
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/* Some CPU low power states require notification at the ISR
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* to allow any operations that needs to be done before kernel
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* switches task or processes nested interrupts. This can be
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* disabled by calling _sys_pm_idle_exit_notification_disable().
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* Alternatively it can be simply ignored if not required.
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*/
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if (sys_pm_idle_exit_notify) {
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_sys_resume();
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}
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#endif
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z_clock_idle_exit();
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}
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#if K_IDLE_PRIO < 0
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#define IDLE_YIELD_IF_COOP() k_yield()
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#else
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#define IDLE_YIELD_IF_COOP() do { } while (false)
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#endif
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void idle(void *unused1, void *unused2, void *unused3)
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{
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ARG_UNUSED(unused1);
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ARG_UNUSED(unused2);
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ARG_UNUSED(unused3);
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#ifdef CONFIG_BOOT_TIME_MEASUREMENT
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/* record timestamp when idling begins */
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extern u32_t z_timestamp_idle;
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z_timestamp_idle = k_cycle_get_32();
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#endif
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while (true) {
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#if SMP_FALLBACK
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k_busy_wait(100);
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k_yield();
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#else
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(void)z_arch_irq_lock();
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sys_power_save_idle();
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IDLE_YIELD_IF_COOP();
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#endif
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}
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}
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