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
13static 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
48void 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}
62EXPORT_SYMBOL_GPL(cpuidle_poll_state_init);
63