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 
17 static int num_idle_cpus = 0;
18 static DEFINE_RAW_SPINLOCK(cpuidle_lock);
19 
imx6q_enter_wait(struct cpuidle_device * dev,struct cpuidle_driver * drv,int index)20 static __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(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(WAIT_CLOCKED);
35 	raw_spin_unlock(&cpuidle_lock);
36 
37 	return index;
38 }
39 
40 static 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  */
imx6q_cpuidle_fec_irqs_used(void)66 void imx6q_cpuidle_fec_irqs_used(void)
67 {
68 	cpuidle_driver_state_disabled(&imx6q_cpuidle_driver, 1, true);
69 }
70 EXPORT_SYMBOL_GPL(imx6q_cpuidle_fec_irqs_used);
71 
imx6q_cpuidle_fec_irqs_unused(void)72 void imx6q_cpuidle_fec_irqs_unused(void)
73 {
74 	cpuidle_driver_state_disabled(&imx6q_cpuidle_driver, 1, false);
75 }
76 EXPORT_SYMBOL_GPL(imx6q_cpuidle_fec_irqs_unused);
77 
imx6q_cpuidle_init(void)78 int __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(true);
82 
83 	return cpuidle_register(&imx6q_cpuidle_driver, NULL);
84 }
85