Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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/export.h>
8#include <linux/irqflags.h>
9#include <linux/sched.h>
10#include <linux/sched/clock.h>
11#include <linux/sched/idle.h>
12#include <linux/sprintf.h>
13#include <linux/types.h>
14
15#define POLL_IDLE_RELAX_COUNT 200
16
17static int __cpuidle poll_idle(struct cpuidle_device *dev,
18 struct cpuidle_driver *drv, int index)
19{
20 u64 time_start;
21
22 time_start = local_clock_noinstr();
23
24 dev->poll_time_limit = false;
25
26 raw_local_irq_enable();
27 if (!current_set_polling_and_test()) {
28 unsigned int loop_count = 0;
29 u64 limit;
30
31 limit = cpuidle_poll_time(drv, dev);
32
33 while (!need_resched()) {
34 cpu_relax();
35 if (loop_count++ < POLL_IDLE_RELAX_COUNT)
36 continue;
37
38 loop_count = 0;
39 if (local_clock_noinstr() - time_start > limit) {
40 dev->poll_time_limit = true;
41 break;
42 }
43 }
44 }
45 raw_local_irq_disable();
46
47 current_clr_polling();
48
49 return index;
50}
51
52void cpuidle_poll_state_init(struct cpuidle_driver *drv)
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->exit_latency_ns = 0;
61 state->target_residency_ns = 0;
62 state->power_usage = -1;
63 state->enter = poll_idle;
64 state->flags = CPUIDLE_FLAG_POLLING;
65}
66EXPORT_SYMBOL_GPL(cpuidle_poll_state_init);