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 = local_clock(); 17 18 dev->poll_time_limit = false; 19 20 local_irq_enable(); 21 if (!current_set_polling_and_test()) { 22 unsigned int loop_count = 0; 23 u64 limit; 24 25 limit = cpuidle_poll_time(drv, dev); 26 27 while (!need_resched()) { 28 cpu_relax(); 29 if (loop_count++ < POLL_IDLE_RELAX_COUNT) 30 continue; 31 32 loop_count = 0; 33 if (local_clock() - time_start > limit) { 34 dev->poll_time_limit = true; 35 break; 36 } 37 } 38 } 39 current_clr_polling(); 40 41 return index; 42 } 43 44 void cpuidle_poll_state_init(struct cpuidle_driver *drv) 45 { 46 struct cpuidle_state *state = &drv->states[0]; 47 48 snprintf(state->name, CPUIDLE_NAME_LEN, "POLL"); 49 snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE"); 50 state->exit_latency = 0; 51 state->target_residency = 0; 52 state->exit_latency_ns = 0; 53 state->target_residency_ns = 0; 54 state->power_usage = -1; 55 state->enter = poll_idle; 56 state->flags = CPUIDLE_FLAG_POLLING; 57 } 58 EXPORT_SYMBOL_GPL(cpuidle_poll_state_init); 59