// SPDX-License-Identifier: GPL-2.0-only /* * poll_state.c - Polling idle state */ #include <linux/cpuidle.h> #include <linux/sched.h> #include <linux/sched/clock.h> #include <linux/sched/idle.h> #define POLL_IDLE_RELAX_COUNT 200 static int __cpuidle poll_idle(struct cpuidle_device *dev, struct cpuidle_driver *drv, int index) { u64 time_start = local_clock(); dev->poll_time_limit = false; local_irq_enable(); if (!current_set_polling_and_test()) { unsigned int loop_count = 0; u64 limit = TICK_NSEC; int i; for (i = 1; i < drv->state_count; i++) { if (drv->states[i].disabled || dev->states_usage[i].disable) continue; limit = (u64)drv->states[i].target_residency * NSEC_PER_USEC; break; } while (!need_resched()) { cpu_relax(); if (loop_count++ < POLL_IDLE_RELAX_COUNT) continue; loop_count = 0; if (local_clock() - time_start > limit) { dev->poll_time_limit = true; break; } } } current_clr_polling(); return index; } void cpuidle_poll_state_init(struct cpuidle_driver *drv) { struct cpuidle_state *state = &drv->states[0]; snprintf(state->name, CPUIDLE_NAME_LEN, "POLL"); snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE"); state->exit_latency = 0; state->target_residency = 0; state->power_usage = -1; state->enter = poll_idle; state->disabled = false; state->flags = CPUIDLE_FLAG_POLLING; } EXPORT_SYMBOL_GPL(cpuidle_poll_state_init);