| 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/sched.h> |
| 8 | #include <linux/sched/clock.h> |
| 9 | #include <linux/sched/idle.h> |
| 10 | |
| 11 | #define POLL_IDLE_RELAX_COUNT 200 |
| 12 | |
| 13 | static int __cpuidle poll_idle(struct cpuidle_device *dev, |
| 14 | struct cpuidle_driver *drv, int index) |
| 15 | { |
| 16 | u64 time_start; |
| 17 | |
| 18 | time_start = local_clock_noinstr(); |
| 19 | |
| 20 | dev->poll_time_limit = false; |
| 21 | |
| 22 | raw_local_irq_enable(); |
| 23 | if (!current_set_polling_and_test()) { |
| 24 | unsigned int loop_count = 0; |
| 25 | u64 limit; |
| 26 | |
| 27 | limit = cpuidle_poll_time(drv, dev); |
| 28 | |
| 29 | while (!need_resched()) { |
| 30 | cpu_relax(); |
| 31 | if (loop_count++ < POLL_IDLE_RELAX_COUNT) |
| 32 | continue; |
| 33 | |
| 34 | loop_count = 0; |
| 35 | if (local_clock_noinstr() - time_start > limit) { |
| 36 | dev->poll_time_limit = true; |
| 37 | break; |
| 38 | } |
| 39 | } |
| 40 | } |
| 41 | raw_local_irq_disable(); |
| 42 | |
| 43 | current_clr_polling(); |
| 44 | |
| 45 | return index; |
| 46 | } |
| 47 | |
| 48 | void cpuidle_poll_state_init(struct cpuidle_driver *drv) |
| 49 | { |
| 50 | struct cpuidle_state *state = &drv->states[0]; |
| 51 | |
| 52 | snprintf(buf: state->name, CPUIDLE_NAME_LEN, fmt: "POLL"); |
| 53 | snprintf(buf: state->desc, CPUIDLE_DESC_LEN, fmt: "CPUIDLE CORE POLL IDLE"); |
| 54 | state->exit_latency = 0; |
| 55 | state->target_residency = 0; |
| 56 | state->exit_latency_ns = 0; |
| 57 | state->target_residency_ns = 0; |
| 58 | state->power_usage = -1; |
| 59 | state->enter = poll_idle; |
| 60 | state->flags = CPUIDLE_FLAG_POLLING; |
| 61 | } |
| 62 | EXPORT_SYMBOL_GPL(cpuidle_poll_state_init); |
| 63 |