summaryrefslogtreecommitdiff
path: root/drivers/cpuidle/cpuidle-psci-domain.c
blob: c2d6d9c3c930dffaaa34dc245f14edeed1c9e7b7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
// SPDX-License-Identifier: GPL-2.0
/*
 * PM domains for CPUs via genpd - managed by cpuidle-psci.
 *
 * Copyright (C) 2019 Linaro Ltd.
 * Author: Ulf Hansson <ulf.hansson@linaro.org>
 *
 */

#define pr_fmt(fmt) "CPUidle PSCI: " fmt

#include <linux/cpu.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/pm_domain.h>
#include <linux/pm_runtime.h>
#include <linux/psci.h>
#include <linux/slab.h>
#include <linux/string.h>

#include "cpuidle-psci.h"

struct psci_pd_provider {
	struct list_head link;
	struct device_node *node;
};

static LIST_HEAD(psci_pd_providers);
static bool psci_pd_allow_domain_state;

static int psci_pd_power_off(struct generic_pm_domain *pd)
{
	struct genpd_power_state *state = &pd->states[pd->state_idx];
	u32 *pd_state;

	if (!state->data)
		return 0;

	if (!psci_pd_allow_domain_state)
		return -EBUSY;

	/* OSI mode is enabled, set the corresponding domain state. */
	pd_state = state->data;
	psci_set_domain_state(*pd_state);

	return 0;
}

static int psci_pd_init(struct device_node *np, bool use_osi)
{
	struct generic_pm_domain *pd;
	struct psci_pd_provider *pd_provider;
	struct dev_power_governor *pd_gov;
	int ret = -ENOMEM;

	pd = dt_idle_pd_alloc(np, psci_dt_parse_state_node);
	if (!pd)
		goto out;

	pd_provider = kzalloc(sizeof(*pd_provider), GFP_KERNEL);
	if (!pd_provider)
		goto free_pd;

	pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN;

	/*
	 * Allow power off when OSI has been successfully enabled.
	 * PREEMPT_RT is not yet ready to enter domain idle states.
	 */
	if (use_osi && !IS_ENABLED(CONFIG_PREEMPT_RT))
		pd->power_off = psci_pd_power_off;
	else
		pd->flags |= GENPD_FLAG_ALWAYS_ON;

	/* Use governor for CPU PM domains if it has some states to manage. */
	pd_gov = pd->states ? &pm_domain_cpu_gov : NULL;

	ret = pm_genpd_init(pd, pd_gov, false);
	if (ret)
		goto free_pd_prov;

	ret = of_genpd_add_provider_simple(np, pd);
	if (ret)
		goto remove_pd;

	pd_provider->node = of_node_get(np);
	list_add(&pd_provider->link, &psci_pd_providers);

	pr_debug("init PM domain %s\n", pd->name);
	return 0;

remove_pd:
	pm_genpd_remove(pd);
free_pd_prov:
	kfree(pd_provider);
free_pd:
	dt_idle_pd_free(pd);
out:
	pr_err("failed to init PM domain ret=%d %pOF\n", ret, np);
	return ret;
}

static void psci_pd_remove(void)
{
	struct psci_pd_provider *pd_provider, *it;
	struct generic_pm_domain *genpd;

	list_for_each_entry_safe_reverse(pd_provider, it,
					 &psci_pd_providers, link) {
		of_genpd_del_provider(pd_provider->node);

		genpd = of_genpd_remove_last(pd_provider->node);
		if (!IS_ERR(genpd))
			kfree(genpd);

		of_node_put(pd_provider->node);
		list_del(&pd_provider->link);
		kfree(pd_provider);
	}
}

static bool psci_pd_try_set_osi_mode(void)
{
	int ret;

	if (!psci_has_osi_support())
		return false;

	ret = psci_set_osi_mode(true);
	if (ret)
		return false;

	return true;
}

static void psci_cpuidle_domain_sync_state(struct device *dev)
{
	/*
	 * All devices have now been attached/probed to the PM domain topology,
	 * hence it's fine to allow domain states to be picked.
	 */
	psci_pd_allow_domain_state = true;
}

static const struct of_device_id psci_of_match[] = {
	{ .compatible = "arm,psci-1.0" },
	{}
};

static int psci_cpuidle_domain_probe(struct platform_device *pdev)
{
	struct device_node *np = pdev->dev.of_node;
	struct device_node *node;
	bool use_osi;
	int ret = 0, pd_count = 0;

	if (!np)
		return -ENODEV;

	/* If OSI mode is supported, let's try to enable it. */
	use_osi = psci_pd_try_set_osi_mode();

	/*
	 * Parse child nodes for the "#power-domain-cells" property and
	 * initialize a genpd/genpd-of-provider pair when it's found.
	 */
	for_each_child_of_node(np, node) {
		if (!of_property_present(node, "#power-domain-cells"))
			continue;

		ret = psci_pd_init(node, use_osi);
		if (ret)
			goto put_node;

		pd_count++;
	}

	/* Bail out if not using the hierarchical CPU topology. */
	if (!pd_count)
		goto no_pd;

	/* Link genpd masters/subdomains to model the CPU topology. */
	ret = dt_idle_pd_init_topology(np);
	if (ret)
		goto remove_pd;

	pr_info("Initialized CPU PM domain topology using %s mode\n",
		use_osi ? "OSI" : "PC");
	return 0;

put_node:
	of_node_put(node);
remove_pd:
	psci_pd_remove();
	pr_err("failed to create CPU PM domains ret=%d\n", ret);
no_pd:
	if (use_osi)
		psci_set_osi_mode(false);
	return ret;
}

static struct platform_driver psci_cpuidle_domain_driver = {
	.probe  = psci_cpuidle_domain_probe,
	.driver = {
		.name = "psci-cpuidle-domain",
		.of_match_table = psci_of_match,
		.sync_state = psci_cpuidle_domain_sync_state,
	},
};

static int __init psci_idle_init_domains(void)
{
	return platform_driver_register(&psci_cpuidle_domain_driver);
}
subsys_initcall(psci_idle_init_domains);