1 /*
2  * Copyright (c) 2011-2014 Samsung Electronics Co., Ltd.
3  *		http://www.samsung.com
4  *
5  * Coupled cpuidle support based on the work of:
6  *	Colin Cross <ccross@android.com>
7  *	Daniel Lezcano <daniel.lezcano@linaro.org>
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2 as
11  * published by the Free Software Foundation.
12 */
13 
14 #include <linux/cpuidle.h>
15 #include <linux/cpu_pm.h>
16 #include <linux/export.h>
17 #include <linux/module.h>
18 #include <linux/platform_device.h>
19 #include <linux/of.h>
20 #include <linux/platform_data/cpuidle-exynos.h>
21 
22 #include <asm/suspend.h>
23 #include <asm/cpuidle.h>
24 
25 static atomic_t exynos_idle_barrier;
26 
27 static struct cpuidle_exynos_data *exynos_cpuidle_pdata;
28 static void (*exynos_enter_aftr)(void);
29 
30 static int exynos_enter_coupled_lowpower(struct cpuidle_device *dev,
31 					 struct cpuidle_driver *drv,
32 					 int index)
33 {
34 	int ret;
35 
36 	exynos_cpuidle_pdata->pre_enter_aftr();
37 
38 	/*
39 	 * Waiting all cpus to reach this point at the same moment
40 	 */
41 	cpuidle_coupled_parallel_barrier(dev, &exynos_idle_barrier);
42 
43 	/*
44 	 * Both cpus will reach this point at the same time
45 	 */
46 	ret = dev->cpu ? exynos_cpuidle_pdata->cpu1_powerdown()
47 		       : exynos_cpuidle_pdata->cpu0_enter_aftr();
48 	if (ret)
49 		index = ret;
50 
51 	/*
52 	 * Waiting all cpus to finish the power sequence before going further
53 	 */
54 	cpuidle_coupled_parallel_barrier(dev, &exynos_idle_barrier);
55 
56 	exynos_cpuidle_pdata->post_enter_aftr();
57 
58 	return index;
59 }
60 
61 static int exynos_enter_lowpower(struct cpuidle_device *dev,
62 				struct cpuidle_driver *drv,
63 				int index)
64 {
65 	int new_index = index;
66 
67 	/* AFTR can only be entered when cores other than CPU0 are offline */
68 	if (num_online_cpus() > 1 || dev->cpu != 0)
69 		new_index = drv->safe_state_index;
70 
71 	if (new_index == 0)
72 		return arm_cpuidle_simple_enter(dev, drv, new_index);
73 
74 	exynos_enter_aftr();
75 
76 	return new_index;
77 }
78 
79 static struct cpuidle_driver exynos_idle_driver = {
80 	.name			= "exynos_idle",
81 	.owner			= THIS_MODULE,
82 	.states = {
83 		[0] = ARM_CPUIDLE_WFI_STATE,
84 		[1] = {
85 			.enter			= exynos_enter_lowpower,
86 			.exit_latency		= 300,
87 			.target_residency	= 100000,
88 			.name			= "C1",
89 			.desc			= "ARM power down",
90 		},
91 	},
92 	.state_count = 2,
93 	.safe_state_index = 0,
94 };
95 
96 static struct cpuidle_driver exynos_coupled_idle_driver = {
97 	.name			= "exynos_coupled_idle",
98 	.owner			= THIS_MODULE,
99 	.states = {
100 		[0] = ARM_CPUIDLE_WFI_STATE,
101 		[1] = {
102 			.enter			= exynos_enter_coupled_lowpower,
103 			.exit_latency		= 5000,
104 			.target_residency	= 10000,
105 			.flags			= CPUIDLE_FLAG_COUPLED |
106 						  CPUIDLE_FLAG_TIMER_STOP,
107 			.name			= "C1",
108 			.desc			= "ARM power down",
109 		},
110 	},
111 	.state_count = 2,
112 	.safe_state_index = 0,
113 };
114 
115 static int exynos_cpuidle_probe(struct platform_device *pdev)
116 {
117 	int ret;
118 
119 	if (IS_ENABLED(CONFIG_SMP) &&
120 	    of_machine_is_compatible("samsung,exynos4210")) {
121 		exynos_cpuidle_pdata = pdev->dev.platform_data;
122 
123 		ret = cpuidle_register(&exynos_coupled_idle_driver,
124 				       cpu_possible_mask);
125 	} else {
126 		exynos_enter_aftr = (void *)(pdev->dev.platform_data);
127 
128 		ret = cpuidle_register(&exynos_idle_driver, NULL);
129 	}
130 
131 	if (ret) {
132 		dev_err(&pdev->dev, "failed to register cpuidle driver\n");
133 		return ret;
134 	}
135 
136 	return 0;
137 }
138 
139 static struct platform_driver exynos_cpuidle_driver = {
140 	.probe	= exynos_cpuidle_probe,
141 	.driver = {
142 		.name = "exynos_cpuidle",
143 	},
144 };
145 
146 module_platform_driver(exynos_cpuidle_driver);
147