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 
imx6q_enter_wait(struct cpuidle_device * dev,struct cpuidle_driver * drv,int index)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 	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 
39 static 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  */
imx6q_cpuidle_fec_irqs_used(void)65 void imx6q_cpuidle_fec_irqs_used(void)
66 {
67 	cpuidle_driver_state_disabled(&imx6q_cpuidle_driver, 1, true);
68 }
69 EXPORT_SYMBOL_GPL(imx6q_cpuidle_fec_irqs_used);
70 
imx6q_cpuidle_fec_irqs_unused(void)71 void imx6q_cpuidle_fec_irqs_unused(void)
72 {
73 	cpuidle_driver_state_disabled(&imx6q_cpuidle_driver, 1, false);
74 }
75 EXPORT_SYMBOL_GPL(imx6q_cpuidle_fec_irqs_unused);
76 
imx6q_cpuidle_init(void)77 int __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