39a8f3b4f9
The removal of the abort handling also absconded with an IRQ lock that is required for reliable operation in the idle loop. Put it back. Once the idle loop has made a decision to enter idle, any interrupt that arrives needs to be masked and delivered AFTER the system enters idle. Otherwise we run the risk of races where the system accepts and processes an interrupt that should have prevented idle, but then goes to sleep anyway having already made the decision. Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
168 lines
4.1 KiB
C
168 lines
4.1 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 <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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#include <logging/log.h>
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#include <ksched.h>
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LOG_MODULE_DECLARE(os, CONFIG_KERNEL_LOG_LEVEL);
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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_PM
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/*
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* Used to allow pm_system_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 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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void __attribute__((weak)) pm_system_resume(void)
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{
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}
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void __attribute__((weak)) pm_system_resume_from_deep_sleep(void)
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{
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}
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/* LCOV_EXCL_STOP */
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#endif /* CONFIG_PM */
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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 && CONFIG_PM
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static enum pm_state pm_save_idle(int32_t ticks)
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{
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static enum pm_state idle_state = PM_STATE_ACTIVE;
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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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* 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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idle_state = pm_system_suspend(ticks);
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if (idle_state == PM_STATE_ACTIVE) {
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pm_idle_exit_notify = 0U;
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}
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return idle_state;
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}
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#endif /* !SMP_FALLBACK */
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void z_pm_save_idle_exit(int32_t ticks)
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{
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#ifdef CONFIG_PM
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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 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 (pm_idle_exit_notify) {
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pm_system_resume();
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}
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#endif /* CONFIG_PM */
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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 *p1, void *unused2, void *unused3)
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{
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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 uint32_t z_timestamp_idle;
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z_timestamp_idle = k_cycle_get_32();
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#endif /* CONFIG_BOOT_TIME_MEASUREMENT */
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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) arch_irq_lock();
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#ifdef CONFIG_SYS_CLOCK_EXISTS
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int32_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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z_set_timeout_expiry((ticks < IDLE_THRESH) ? 1 : ticks, true);
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#ifdef CONFIG_PM
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_kernel.idle = ticks;
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/* Check power policy and decide if we are going to sleep or
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* just idle.
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*/
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if (pm_save_idle(ticks) == PM_STATE_ACTIVE) {
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k_cpu_idle();
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}
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#else /* CONFIG_PM */
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k_cpu_idle();
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#endif /* CONFIG_PM */
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#else /* CONFIG_SYS_CLOCK_EXISTS */
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k_cpu_idle();
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#endif /* CONFIG_SYS_CLOCK_EXISTS */
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IDLE_YIELD_IF_COOP();
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#endif /* SMP_FALLBACK */
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}
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}
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