1 // SPDX-License-Identifier: GPL-2.0-only
3 * poll_state.c - Polling idle state
6 #include <linux/cpuidle.h>
7 #include <linux/sched.h>
8 #include <linux/sched/clock.h>
9 #include <linux/sched/idle.h>
11 #define POLL_IDLE_RELAX_COUNT 200
13 static int __cpuidle poll_idle(struct cpuidle_device *dev,
14 struct cpuidle_driver *drv, int index)
16 u64 time_start = local_clock();
18 dev->poll_time_limit = false;
21 if (!current_set_polling_and_test()) {
22 unsigned int loop_count = 0;
23 u64 limit = TICK_NSEC;
26 for (i = 1; i < drv->state_count; i++) {
27 if (drv->states[i].disabled || dev->states_usage[i].disable)
30 limit = (u64)drv->states[i].target_residency * NSEC_PER_USEC;
34 while (!need_resched()) {
36 if (loop_count++ < POLL_IDLE_RELAX_COUNT)
40 if (local_clock() - time_start > limit) {
41 dev->poll_time_limit = true;
46 current_clr_polling();
51 void cpuidle_poll_state_init(struct cpuidle_driver *drv)
53 struct cpuidle_state *state = &drv->states[0];
55 snprintf(state->name, CPUIDLE_NAME_LEN, "POLL");
56 snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE");
57 state->exit_latency = 0;
58 state->target_residency = 0;
59 state->power_usage = -1;
60 state->enter = poll_idle;
61 state->disabled = false;
62 state->flags = CPUIDLE_FLAG_POLLING;
64 EXPORT_SYMBOL_GPL(cpuidle_poll_state_init);