65 lines
1.4 KiB
C
65 lines
1.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* poll_state.c - Polling idle state
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*/
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#include <linux/cpuidle.h>
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#include <linux/sched.h>
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#include <linux/sched/clock.h>
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#include <linux/sched/idle.h>
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#define POLL_IDLE_RELAX_COUNT 200
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static int __cpuidle poll_idle(struct cpuidle_device *dev,
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struct cpuidle_driver *drv, int index)
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{
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u64 time_start = local_clock();
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dev->poll_time_limit = false;
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local_irq_enable();
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if (!current_set_polling_and_test()) {
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unsigned int loop_count = 0;
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u64 limit = TICK_NSEC;
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int i;
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for (i = 1; i < drv->state_count; i++) {
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if (drv->states[i].disabled || dev->states_usage[i].disable)
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continue;
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limit = (u64)drv->states[i].target_residency * NSEC_PER_USEC;
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break;
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}
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while (!need_resched()) {
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cpu_relax();
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if (loop_count++ < POLL_IDLE_RELAX_COUNT)
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continue;
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loop_count = 0;
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if (local_clock() - time_start > limit) {
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dev->poll_time_limit = true;
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break;
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}
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}
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}
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current_clr_polling();
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return index;
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}
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void cpuidle_poll_state_init(struct cpuidle_driver *drv)
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{
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struct cpuidle_state *state = &drv->states[0];
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snprintf(state->name, CPUIDLE_NAME_LEN, "POLL");
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snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE");
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state->exit_latency = 0;
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state->target_residency = 0;
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state->power_usage = -1;
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state->enter = poll_idle;
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state->disabled = false;
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state->flags = CPUIDLE_FLAG_POLLING;
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}
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EXPORT_SYMBOL_GPL(cpuidle_poll_state_init);
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