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
25static atomic_t exynos_idle_barrier;
26
27static struct cpuidle_exynos_data *exynos_cpuidle_pdata;
28static void (*exynos_enter_aftr)(void);
29
30static 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
61static 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
79static 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
96static 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
115static 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
139static struct platform_driver exynos_cpuidle_driver = {
140	.probe	= exynos_cpuidle_probe,
141	.driver = {
142		.name = "exynos_cpuidle",
143	},
144};
145
146module_platform_driver(exynos_cpuidle_driver);
147