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 
16 static int num_idle_cpus = 0;
17 static DEFINE_RAW_SPINLOCK(cpuidle_lock);
18 
19 static 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 	cpu_do_idle();
28 
29 	raw_spin_lock(&cpuidle_lock);
30 	if (num_idle_cpus-- == num_online_cpus())
31 		imx6_set_lpm(WAIT_CLOCKED);
32 	raw_spin_unlock(&cpuidle_lock);
33 
34 	return index;
35 }
36 
37 static struct cpuidle_driver imx6q_cpuidle_driver = {
38 	.name = "imx6q_cpuidle",
39 	.owner = THIS_MODULE,
40 	.states = {
41 		/* WFI */
42 		ARM_CPUIDLE_WFI_STATE,
43 		/* WAIT */
44 		{
45 			.exit_latency = 50,
46 			.target_residency = 75,
47 			.flags = CPUIDLE_FLAG_TIMER_STOP,
48 			.enter = imx6q_enter_wait,
49 			.name = "WAIT",
50 			.desc = "Clock off",
51 		},
52 	},
53 	.state_count = 2,
54 	.safe_state_index = 0,
55 };
56 
57 /*
58  * i.MX6 Q/DL has an erratum (ERR006687) that prevents the FEC from waking the
59  * CPUs when they are in wait(unclocked) state. As the hardware workaround isn't
60  * applicable to all boards, disable the deeper idle state when the workaround
61  * isn't present and the FEC is in use.
62  */
63 void imx6q_cpuidle_fec_irqs_used(void)
64 {
65 	imx6q_cpuidle_driver.states[1].disabled = true;
66 }
67 EXPORT_SYMBOL_GPL(imx6q_cpuidle_fec_irqs_used);
68 
69 void imx6q_cpuidle_fec_irqs_unused(void)
70 {
71 	imx6q_cpuidle_driver.states[1].disabled = false;
72 }
73 EXPORT_SYMBOL_GPL(imx6q_cpuidle_fec_irqs_unused);
74 
75 int __init imx6q_cpuidle_init(void)
76 {
77 	/* Set INT_MEM_CLK_LPM bit to get a reliable WAIT mode support */
78 	imx6_set_int_mem_clk_lpm(true);
79 
80 	return cpuidle_register(&imx6q_cpuidle_driver, NULL);
81 }
82