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