// 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;

  		limit = cpuidle_poll_time(drv, dev);

  		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->exit_latency_ns = 0;
  	state->target_residency_ns = 0;

  	state->power_usage = -1;
  	state->enter = poll_idle;

  	state->flags = CPUIDLE_FLAG_POLLING;
  }

  EXPORT_SYMBOL_GPL(cpuidle_poll_state_init);