1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * poll_state.c - Polling idle state 4 */ 5 6 #include <linux/cpuidle.h> 7 #include <linux/sched.h> 8 #include <linux/sched/clock.h> 9 #include <linux/sched/idle.h> 10 11 #define POLL_IDLE_RELAX_COUNT 200 12 13 static int __cpuidle poll_idle(struct cpuidle_device *dev, 14 struct cpuidle_driver *drv, int index) 15 { 16 u64 time_start; 17 18 time_start = local_clock_noinstr(); 19 20 dev->poll_time_limit = false; 21 22 raw_local_irq_enable(); 23 if (!current_set_polling_and_test()) { 24 unsigned int loop_count = 0; 25 u64 limit; 26 27 limit = cpuidle_poll_time(drv, dev); 28 29 while (!need_resched()) { 30 cpu_relax(); 31 if (loop_count++ < POLL_IDLE_RELAX_COUNT) 32 continue; 33 34 loop_count = 0; 35 if (local_clock_noinstr() - time_start > limit) { 36 dev->poll_time_limit = true; 37 break; 38 } 39 } 40 } 41 raw_local_irq_disable(); 42 43 current_clr_polling(); 44 45 return index; 46 } 47 48 void cpuidle_poll_state_init(struct cpuidle_driver *drv) 49 { 50 struct cpuidle_state *state = &drv->states[0]; 51 52 snprintf(state->name, CPUIDLE_NAME_LEN, "POLL"); 53 snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE"); 54 state->exit_latency = 0; 55 state->target_residency = 0; 56 state->exit_latency_ns = 0; 57 state->target_residency_ns = 0; 58 state->power_usage = -1; 59 state->enter = poll_idle; 60 state->flags = CPUIDLE_FLAG_POLLING; 61 } 62 EXPORT_SYMBOL_GPL(cpuidle_poll_state_init); 63