1// SPDX-License-Identifier: GPL-2.0
2/*
3 * PM domains for CPUs via genpd - managed by cpuidle-psci.
4 *
5 * Copyright (C) 2019 Linaro Ltd.
6 * Author: Ulf Hansson <ulf.hansson@linaro.org>
7 *
8 */
9
10#define pr_fmt(fmt) "CPUidle PSCI: " fmt
11
12#include <linux/cpu.h>
13#include <linux/device.h>
14#include <linux/kernel.h>
15#include <linux/platform_device.h>
16#include <linux/pm_domain.h>
17#include <linux/pm_runtime.h>
18#include <linux/psci.h>
19#include <linux/slab.h>
20#include <linux/string.h>
21
22#include "cpuidle-psci.h"
23#include "dt_idle_genpd.h"
24
25struct psci_pd_provider {
26 struct list_head link;
27 struct device_node *node;
28};
29
30static LIST_HEAD(psci_pd_providers);
31
32static int psci_pd_power_off(struct generic_pm_domain *pd)
33{
34 struct genpd_power_state *state = &pd->states[pd->state_idx];
35 u32 *pd_state;
36
37 if (!state->data)
38 return 0;
39
40 /* OSI mode is enabled, set the corresponding domain state. */
41 pd_state = state->data;
42 psci_set_domain_state(pd, state_idx: pd->state_idx, state: *pd_state);
43
44 return 0;
45}
46
47static int psci_pd_init(struct device_node *np, bool use_osi)
48{
49 struct generic_pm_domain *pd;
50 struct psci_pd_provider *pd_provider;
51 struct dev_power_governor *pd_gov;
52 int ret = -ENOMEM;
53
54 pd = dt_idle_pd_alloc(np, parse_state: psci_dt_parse_state_node);
55 if (!pd)
56 goto out;
57
58 pd_provider = kzalloc(sizeof(*pd_provider), GFP_KERNEL);
59 if (!pd_provider)
60 goto free_pd;
61
62 pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN;
63
64 /*
65 * Allow power off when OSI has been successfully enabled.
66 * On a PREEMPT_RT based configuration the domain idle states are
67 * supported, but only during system-wide suspend.
68 */
69 if (use_osi) {
70 pd->power_off = psci_pd_power_off;
71 pd->flags |= GENPD_FLAG_ACTIVE_WAKEUP;
72 if (IS_ENABLED(CONFIG_PREEMPT_RT))
73 pd->flags |= GENPD_FLAG_RPM_ALWAYS_ON;
74 } else {
75 pd->flags |= GENPD_FLAG_ALWAYS_ON;
76 }
77
78 /* Use governor for CPU PM domains if it has some states to manage. */
79 pd_gov = pd->states ? &pm_domain_cpu_gov : NULL;
80
81 ret = pm_genpd_init(genpd: pd, gov: pd_gov, is_off: false);
82 if (ret)
83 goto free_pd_prov;
84
85 ret = of_genpd_add_provider_simple(np, genpd: pd);
86 if (ret)
87 goto remove_pd;
88
89 pd_provider->node = of_node_get(node: np);
90 list_add(new: &pd_provider->link, head: &psci_pd_providers);
91
92 pr_debug("init PM domain %s\n", pd->name);
93 return 0;
94
95remove_pd:
96 pm_genpd_remove(genpd: pd);
97free_pd_prov:
98 kfree(objp: pd_provider);
99free_pd:
100 dt_idle_pd_free(pd);
101out:
102 pr_err("failed to init PM domain ret=%d %pOF\n", ret, np);
103 return ret;
104}
105
106static void psci_pd_remove(void)
107{
108 struct psci_pd_provider *pd_provider, *it;
109 struct generic_pm_domain *genpd;
110
111 list_for_each_entry_safe_reverse(pd_provider, it,
112 &psci_pd_providers, link) {
113 of_genpd_del_provider(np: pd_provider->node);
114
115 genpd = of_genpd_remove_last(np: pd_provider->node);
116 if (!IS_ERR(ptr: genpd))
117 kfree(objp: genpd);
118
119 of_node_put(node: pd_provider->node);
120 list_del(entry: &pd_provider->link);
121 kfree(objp: pd_provider);
122 }
123}
124
125static const struct of_device_id psci_of_match[] = {
126 { .compatible = "arm,psci-1.0" },
127 {}
128};
129
130static int psci_cpuidle_domain_probe(struct platform_device *pdev)
131{
132 struct device_node *np = pdev->dev.of_node;
133 bool use_osi = psci_has_osi_support();
134 int ret = 0, pd_count = 0;
135
136 if (!np)
137 return -ENODEV;
138
139 /*
140 * Parse child nodes for the "#power-domain-cells" property and
141 * initialize a genpd/genpd-of-provider pair when it's found.
142 */
143 for_each_child_of_node_scoped(np, node) {
144 if (!of_property_present(np: node, propname: "#power-domain-cells"))
145 continue;
146
147 ret = psci_pd_init(np: node, use_osi);
148 if (ret)
149 goto exit;
150
151 pd_count++;
152 }
153
154 /* Bail out if not using the hierarchical CPU topology. */
155 if (!pd_count)
156 return 0;
157
158 /* Link genpd masters/subdomains to model the CPU topology. */
159 ret = dt_idle_pd_init_topology(np);
160 if (ret)
161 goto remove_pd;
162
163 /* let's try to enable OSI. */
164 ret = psci_set_osi_mode(enable: use_osi);
165 if (ret)
166 goto remove_pd;
167
168 pr_info("Initialized CPU PM domain topology using %s mode\n",
169 use_osi ? "OSI" : "PC");
170 return 0;
171
172remove_pd:
173 dt_idle_pd_remove_topology(np);
174 psci_pd_remove();
175exit:
176 pr_err("failed to create CPU PM domains ret=%d\n", ret);
177 return ret;
178}
179
180static struct platform_driver psci_cpuidle_domain_driver = {
181 .probe = psci_cpuidle_domain_probe,
182 .driver = {
183 .name = "psci-cpuidle-domain",
184 .of_match_table = psci_of_match,
185 },
186};
187
188static int __init psci_idle_init_domains(void)
189{
190 return platform_driver_register(&psci_cpuidle_domain_driver);
191}
192core_initcall(psci_idle_init_domains);
193

source code of linux/drivers/cpuidle/cpuidle-psci-domain.c