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/proc-fns.h>
14 #include <asm/suspend.h>
15 
16 #include "common.h"
17 #include "cpuidle.h"
18 
19 static int imx6sx_idle_finish(unsigned long val)
20 {
21 	cpu_do_idle();
22 
23 	return 0;
24 }
25 
26 static int imx6sx_enter_wait(struct cpuidle_device *dev,
27 			    struct cpuidle_driver *drv, int index)
28 {
29 	imx6q_set_lpm(WAIT_UNCLOCKED);
30 
31 	switch (index) {
32 	case 1:
33 		cpu_do_idle();
34 		break;
35 	case 2:
36 		imx6_enable_rbc(true);
37 		imx_gpc_set_arm_power_in_lpm(true);
38 		imx_set_cpu_jump(0, v7_cpu_resume);
39 		/* Need to notify there is a cpu pm operation. */
40 		cpu_pm_enter();
41 		cpu_cluster_pm_enter();
42 
43 		cpu_suspend(0, imx6sx_idle_finish);
44 
45 		cpu_cluster_pm_exit();
46 		cpu_pm_exit();
47 		imx_gpc_set_arm_power_in_lpm(false);
48 		imx6_enable_rbc(false);
49 		break;
50 	default:
51 		break;
52 	}
53 
54 	imx6q_set_lpm(WAIT_CLOCKED);
55 
56 	return index;
57 }
58 
59 static struct cpuidle_driver imx6sx_cpuidle_driver = {
60 	.name = "imx6sx_cpuidle",
61 	.owner = THIS_MODULE,
62 	.states = {
63 		/* WFI */
64 		ARM_CPUIDLE_WFI_STATE,
65 		/* WAIT */
66 		{
67 			.exit_latency = 50,
68 			.target_residency = 75,
69 			.flags = CPUIDLE_FLAG_TIMER_STOP,
70 			.enter = imx6sx_enter_wait,
71 			.name = "WAIT",
72 			.desc = "Clock off",
73 		},
74 		/* WAIT + ARM power off  */
75 		{
76 			/*
77 			 * ARM gating 31us * 5 + RBC clear 65us
78 			 * and some margin for SW execution, here set it
79 			 * to 300us.
80 			 */
81 			.exit_latency = 300,
82 			.target_residency = 500,
83 			.enter = imx6sx_enter_wait,
84 			.name = "LOW-POWER-IDLE",
85 			.desc = "ARM power off",
86 		},
87 	},
88 	.state_count = 3,
89 	.safe_state_index = 0,
90 };
91 
92 int __init imx6sx_cpuidle_init(void)
93 {
94 	imx6_enable_rbc(false);
95 	/*
96 	 * set ARM power up/down timing to the fastest,
97 	 * sw2iso and sw can be set to one 32K cycle = 31us
98 	 * except for power up sw2iso which need to be
99 	 * larger than LDO ramp up time.
100 	 */
101 	imx_gpc_set_arm_power_up_timing(2, 1);
102 	imx_gpc_set_arm_power_down_timing(1, 1);
103 
104 	return cpuidle_register(&imx6sx_cpuidle_driver, NULL);
105 }
106