[linux-block.git] / drivers / cpuidle / poll_state.c

// 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);
Commit	Line	Data
55716d26	1	// SPDX-License-Identifier: GPL-2.0-only
34c2f65b RW	2	/*
34c2f65b RW	3	* poll_state.c - Polling idle state
34c2f65b RW	4	*/
	5
	6	#include <linux/cpuidle.h>
	7	#include <linux/sched.h>
a37b969a	8	#include <linux/sched/clock.h>
34c2f65b RW	9	#include <linux/sched/idle.h>
34c2f65b RW	10
4dc2375c	11	#define POLL_IDLE_RELAX_COUNT 200
a37b969a	12
34c2f65b RW	13	static int __cpuidle poll_idle(struct cpuidle_device *dev,
	14	struct cpuidle_driver *drv, int index)
	15	{
a37b969a RW	16	u64 time_start = local_clock();
a37b969a RW	17
5f26bdce RW	18	dev->poll_time_limit = false;
5f26bdce RW	19
34c2f65b RW	20	local_irq_enable();
34c2f65b RW	21	if (!current_set_polling_and_test()) {
4dc2375c	22	unsigned int loop_count = 0;
1617971c	23	u64 limit = TICK_NSEC;
800fb34a RW	24	int i;
	25
	26	for (i = 1; i < drv->state_count; i++) {
	27	if (drv->states[i].disabled \|\| dev->states_usage[i].disable)
	28	continue;
	29
	30	limit = (u64)drv->states[i].target_residency * NSEC_PER_USEC;
	31	break;
	32	}
4dc2375c	33
a37b969a	34	while (!need_resched()) {
34c2f65b	35	cpu_relax();
4dc2375c RW	36	if (loop_count++ < POLL_IDLE_RELAX_COUNT)
4dc2375c RW	37	continue;
a37b969a	38
4dc2375c	39	loop_count = 0;
01bad1c6	40	if (local_clock() - time_start > limit) {
5f26bdce	41	dev->poll_time_limit = true;
a37b969a	42	break;
5f26bdce	43	}
a37b969a	44	}
34c2f65b RW	45	}
	46	current_clr_polling();
	47
	48	return index;
	49	}
	50
1b39e3f8	51	void cpuidle_poll_state_init(struct cpuidle_driver *drv)
34c2f65b RW	52	{
	53	struct cpuidle_state *state = &drv->states[0];
	54
	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;
	63	}
1b39e3f8	64	EXPORT_SYMBOL_GPL(cpuidle_poll_state_init);