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/cacheflush.h>
13 #include <asm/cpuidle.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 	/*
22 	 * for Cortex-A7 which has an internal L2
23 	 * cache, need to flush it before powering
24 	 * down ARM platform, since flushing L1 cache
25 	 * here again has very small overhead, compared
26 	 * to adding conditional code for L2 cache type,
27 	 * just call flush_cache_all() is fine.
28 	 */
29 	flush_cache_all();
30 	cpu_do_idle();
31 
32 	return 0;
33 }
34 
35 static int imx6sx_enter_wait(struct cpuidle_device *dev,
36 			    struct cpuidle_driver *drv, int index)
37 {
38 	imx6_set_lpm(WAIT_UNCLOCKED);
39 
40 	switch (index) {
41 	case 1:
42 		cpu_do_idle();
43 		break;
44 	case 2:
45 		imx6_enable_rbc(true);
46 		imx_gpc_set_arm_power_in_lpm(true);
47 		imx_set_cpu_jump(0, v7_cpu_resume);
48 		/* Need to notify there is a cpu pm operation. */
49 		cpu_pm_enter();
50 		cpu_cluster_pm_enter();
51 
52 		cpu_suspend(0, imx6sx_idle_finish);
53 
54 		cpu_cluster_pm_exit();
55 		cpu_pm_exit();
56 		imx_gpc_set_arm_power_in_lpm(false);
57 		imx6_enable_rbc(false);
58 		break;
59 	default:
60 		break;
61 	}
62 
63 	imx6_set_lpm(WAIT_CLOCKED);
64 
65 	return index;
66 }
67 
68 static struct cpuidle_driver imx6sx_cpuidle_driver = {
69 	.name = "imx6sx_cpuidle",
70 	.owner = THIS_MODULE,
71 	.states = {
72 		/* WFI */
73 		ARM_CPUIDLE_WFI_STATE,
74 		/* WAIT */
75 		{
76 			.exit_latency = 50,
77 			.target_residency = 75,
78 			.flags = CPUIDLE_FLAG_TIMER_STOP,
79 			.enter = imx6sx_enter_wait,
80 			.name = "WAIT",
81 			.desc = "Clock off",
82 		},
83 		/* WAIT + ARM power off  */
84 		{
85 			/*
86 			 * ARM gating 31us * 5 + RBC clear 65us
87 			 * and some margin for SW execution, here set it
88 			 * to 300us.
89 			 */
90 			.exit_latency = 300,
91 			.target_residency = 500,
92 			.enter = imx6sx_enter_wait,
93 			.name = "LOW-POWER-IDLE",
94 			.desc = "ARM power off",
95 		},
96 	},
97 	.state_count = 3,
98 	.safe_state_index = 0,
99 };
100 
101 int __init imx6sx_cpuidle_init(void)
102 {
103 	imx6_set_int_mem_clk_lpm(true);
104 	imx6_enable_rbc(false);
105 	/*
106 	 * set ARM power up/down timing to the fastest,
107 	 * sw2iso and sw can be set to one 32K cycle = 31us
108 	 * except for power up sw2iso which need to be
109 	 * larger than LDO ramp up time.
110 	 */
111 	imx_gpc_set_arm_power_up_timing(2, 1);
112 	imx_gpc_set_arm_power_down_timing(1, 1);
113 
114 	return cpuidle_register(&imx6sx_cpuidle_driver, NULL);
115 }
116