1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2012 Freescale Semiconductor, Inc.
4 */
5
6#include <linux/context_tracking.h>
7#include <linux/cpuidle.h>
8#include <linux/module.h>
9#include <asm/cpuidle.h>
10
11#include <soc/imx/cpuidle.h>
12
13#include "common.h"
14#include "cpuidle.h"
15#include "hardware.h"
16
17static int num_idle_cpus = 0;
18static DEFINE_RAW_SPINLOCK(cpuidle_lock);
19
20static __cpuidle int imx6q_enter_wait(struct cpuidle_device *dev,
21 struct cpuidle_driver *drv, int index)
22{
23 raw_spin_lock(&cpuidle_lock);
24 if (++num_idle_cpus == num_online_cpus())
25 imx6_set_lpm(mode: WAIT_UNCLOCKED);
26 raw_spin_unlock(&cpuidle_lock);
27
28 ct_cpuidle_enter();
29 cpu_do_idle();
30 ct_cpuidle_exit();
31
32 raw_spin_lock(&cpuidle_lock);
33 if (num_idle_cpus-- == num_online_cpus())
34 imx6_set_lpm(mode: WAIT_CLOCKED);
35 raw_spin_unlock(&cpuidle_lock);
36
37 return index;
38}
39
40static struct cpuidle_driver imx6q_cpuidle_driver = {
41 .name = "imx6q_cpuidle",
42 .owner = THIS_MODULE,
43 .states = {
44 /* WFI */
45 ARM_CPUIDLE_WFI_STATE,
46 /* WAIT */
47 {
48 .exit_latency = 50,
49 .target_residency = 75,
50 .flags = CPUIDLE_FLAG_TIMER_STOP | CPUIDLE_FLAG_RCU_IDLE,
51 .enter = imx6q_enter_wait,
52 .name = "WAIT",
53 .desc = "Clock off",
54 },
55 },
56 .state_count = 2,
57 .safe_state_index = 0,
58};
59
60/*
61 * i.MX6 Q/DL has an erratum (ERR006687) that prevents the FEC from waking the
62 * CPUs when they are in wait(unclocked) state. As the hardware workaround isn't
63 * applicable to all boards, disable the deeper idle state when the workaround
64 * isn't present and the FEC is in use.
65 */
66void imx6q_cpuidle_fec_irqs_used(void)
67{
68 cpuidle_driver_state_disabled(drv: &imx6q_cpuidle_driver, idx: 1, disable: true);
69}
70EXPORT_SYMBOL_GPL(imx6q_cpuidle_fec_irqs_used);
71
72void imx6q_cpuidle_fec_irqs_unused(void)
73{
74 cpuidle_driver_state_disabled(drv: &imx6q_cpuidle_driver, idx: 1, disable: false);
75}
76EXPORT_SYMBOL_GPL(imx6q_cpuidle_fec_irqs_unused);
77
78int __init imx6q_cpuidle_init(void)
79{
80 /* Set INT_MEM_CLK_LPM bit to get a reliable WAIT mode support */
81 imx6_set_int_mem_clk_lpm(enable: true);
82
83 return cpuidle_register(drv: &imx6q_cpuidle_driver, NULL);
84}
85

source code of linux/arch/arm/mach-imx/cpuidle-imx6q.c