[linux-2.6-block.git] / drivers / cpuidle / poll_state.c

/*
 * poll_state.c - Polling idle state
 *
 * This file is released under the GPLv2.
 */

#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
34c2f65b RW	1	/*
	2	* poll_state.c - Polling idle state
	3	*
	4	* This file is released under the GPLv2.
	5	*/
	6
	7	#include <linux/cpuidle.h>
	8	#include <linux/sched.h>
a37b969a	9	#include <linux/sched/clock.h>
34c2f65b RW	10	#include <linux/sched/idle.h>
34c2f65b RW	11
4dc2375c	12	#define POLL_IDLE_RELAX_COUNT 200
a37b969a	13
34c2f65b RW	14	static int __cpuidle poll_idle(struct cpuidle_device *dev,
	15	struct cpuidle_driver *drv, int index)
	16	{
a37b969a RW	17	u64 time_start = local_clock();
a37b969a RW	18
5f26bdce RW	19	dev->poll_time_limit = false;
5f26bdce RW	20
34c2f65b RW	21	local_irq_enable();
34c2f65b RW	22	if (!current_set_polling_and_test()) {
4dc2375c	23	unsigned int loop_count = 0;
1617971c	24	u64 limit = TICK_NSEC;
800fb34a RW	25	int i;
	26
	27	for (i = 1; i < drv->state_count; i++) {
	28	if (drv->states[i].disabled \|\| dev->states_usage[i].disable)
	29	continue;
	30
	31	limit = (u64)drv->states[i].target_residency * NSEC_PER_USEC;
	32	break;
	33	}
4dc2375c	34
a37b969a	35	while (!need_resched()) {
34c2f65b	36	cpu_relax();
4dc2375c RW	37	if (loop_count++ < POLL_IDLE_RELAX_COUNT)
4dc2375c RW	38	continue;
a37b969a	39
4dc2375c	40	loop_count = 0;
01bad1c6	41	if (local_clock() - time_start > limit) {
5f26bdce	42	dev->poll_time_limit = true;
a37b969a	43	break;
5f26bdce	44	}
a37b969a	45	}
34c2f65b RW	46	}
	47	current_clr_polling();
	48
	49	return index;
	50	}
	51
1b39e3f8	52	void cpuidle_poll_state_init(struct cpuidle_driver *drv)
34c2f65b RW	53	{
	54	struct cpuidle_state *state = &drv->states[0];
	55
	56	snprintf(state->name, CPUIDLE_NAME_LEN, "POLL");
	57	snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE");
	58	state->exit_latency = 0;
	59	state->target_residency = 0;
	60	state->power_usage = -1;
	61	state->enter = poll_idle;
	62	state->disabled = false;
	63	state->flags = CPUIDLE_FLAG_POLLING;
	64	}
1b39e3f8	65	EXPORT_SYMBOL_GPL(cpuidle_poll_state_init);