1 /*
2  * Copyright (C) 2014 Freescale Semiconductor, Inc.
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  */
8 
9 #include <linux/cpuidle.h>
10 #include <linux/cpu_pm.h>
11 #include <linux/module.h>
12 #include <asm/cpuidle.h>
13 #include <asm/suspend.h>
14 
15 #include "common.h"
16 #include "cpuidle.h"
17 
18 static int imx6sx_idle_finish(unsigned long val)
19 {
20 	cpu_do_idle();
21 
22 	return 0;
23 }
24 
25 static int imx6sx_enter_wait(struct cpuidle_device *dev,
26 			    struct cpuidle_driver *drv, int index)
27 {
28 	imx6_set_lpm(WAIT_UNCLOCKED);
29 
30 	switch (index) {
31 	case 1:
32 		cpu_do_idle();
33 		break;
34 	case 2:
35 		imx6_enable_rbc(true);
36 		imx_gpc_set_arm_power_in_lpm(true);
37 		imx_set_cpu_jump(0, v7_cpu_resume);
38 		/* Need to notify there is a cpu pm operation. */
39 		cpu_pm_enter();
40 		cpu_cluster_pm_enter();
41 
42 		cpu_suspend(0, imx6sx_idle_finish);
43 
44 		cpu_cluster_pm_exit();
45 		cpu_pm_exit();
46 		imx_gpc_set_arm_power_in_lpm(false);
47 		imx6_enable_rbc(false);
48 		break;
49 	default:
50 		break;
51 	}
52 
53 	imx6_set_lpm(WAIT_CLOCKED);
54 
55 	return index;
56 }
57 
58 static struct cpuidle_driver imx6sx_cpuidle_driver = {
59 	.name = "imx6sx_cpuidle",
60 	.owner = THIS_MODULE,
61 	.states = {
62 		/* WFI */
63 		ARM_CPUIDLE_WFI_STATE,
64 		/* WAIT */
65 		{
66 			.exit_latency = 50,
67 			.target_residency = 75,
68 			.flags = CPUIDLE_FLAG_TIMER_STOP,
69 			.enter = imx6sx_enter_wait,
70 			.name = "WAIT",
71 			.desc = "Clock off",
72 		},
73 		/* WAIT + ARM power off  */
74 		{
75 			/*
76 			 * ARM gating 31us * 5 + RBC clear 65us
77 			 * and some margin for SW execution, here set it
78 			 * to 300us.
79 			 */
80 			.exit_latency = 300,
81 			.target_residency = 500,
82 			.enter = imx6sx_enter_wait,
83 			.name = "LOW-POWER-IDLE",
84 			.desc = "ARM power off",
85 		},
86 	},
87 	.state_count = 3,
88 	.safe_state_index = 0,
89 };
90 
91 int __init imx6sx_cpuidle_init(void)
92 {
93 	imx6_enable_rbc(false);
94 	/*
95 	 * set ARM power up/down timing to the fastest,
96 	 * sw2iso and sw can be set to one 32K cycle = 31us
97 	 * except for power up sw2iso which need to be
98 	 * larger than LDO ramp up time.
99 	 */
100 	imx_gpc_set_arm_power_up_timing(2, 1);
101 	imx_gpc_set_arm_power_down_timing(1, 1);
102 
103 	return cpuidle_register(&imx6sx_cpuidle_driver, NULL);
104 }
105