/* * Copyright (c) 2011-2015 Wind River Systems, Inc. * Copyright (c) 2017 Oticon A/S * * SPDX-License-Identifier: Apache-2.0 */ /** * @file CPU power management code for POSIX * * This module provides an implementation of the architecture-specific * k_cpu_idle() primitive required by the kernel idle loop component. * It can be called within an implementation of _sys_power_save_idle(), * which is provided for the kernel by the platform. * * The module also provides an implementation of k_cpu_atomic_idle(), which * atomically re-enables interrupts and enters low power mode. * */ #include "posix_core.h" #include "posix_soc_if.h" /** * * @brief Power save idle routine for IA-32 * * This function will be called by the kernel idle loop or possibly within * an implementation of _sys_power_save_idle in the kernel when the * '_sys_power_save_flag' variable is non-zero. * * This function is just a pass thru to the SOC one * * @return N/A */ void k_cpu_idle(void) { posix_irq_full_unlock(); posix_halt_cpu(); } /** * * @brief Atomically re-enable interrupts and enter low power mode * * INTERNAL * The requirements for k_cpu_atomic_idle() are as follows: * 1) The enablement of interrupts and entering a low-power mode needs to be * atomic, i.e. there should be no period of time where interrupts are * enabled before the processor enters a low-power mode. See the comments * in k_lifo_get(), for example, of the race condition that * occurs if this requirement is not met. * * 2) After waking up from the low-power mode, the interrupt lockout state * must be restored as indicated in the 'imask' input parameter. * * This function is just a pass thru to the SOC one * * @return N/A */ void k_cpu_atomic_idle(unsigned int imask) { posix_atomic_halt_cpu(imask); }