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
25 struct psci_pd_provider {
26 struct list_head link;
27 struct device_node *node;
28 };
29
30 static LIST_HEAD(psci_pd_providers);
31 static bool psci_pd_allow_domain_state;
32
psci_pd_power_off(struct generic_pm_domain * pd)33 static int psci_pd_power_off(struct generic_pm_domain *pd)
34 {
35 struct genpd_power_state *state = &pd->states[pd->state_idx];
36 u32 *pd_state;
37
38 if (!state->data)
39 return 0;
40
41 if (!psci_pd_allow_domain_state)
42 return -EBUSY;
43
44 /* OSI mode is enabled, set the corresponding domain state. */
45 pd_state = state->data;
46 psci_set_domain_state(*pd_state);
47
48 return 0;
49 }
50
psci_pd_init(struct device_node * np,bool use_osi)51 static int psci_pd_init(struct device_node *np, bool use_osi)
52 {
53 struct generic_pm_domain *pd;
54 struct psci_pd_provider *pd_provider;
55 struct dev_power_governor *pd_gov;
56 int ret = -ENOMEM;
57
58 pd = dt_idle_pd_alloc(np, psci_dt_parse_state_node);
59 if (!pd)
60 goto out;
61
62 pd_provider = kzalloc(sizeof(*pd_provider), GFP_KERNEL);
63 if (!pd_provider)
64 goto free_pd;
65
66 pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN;
67
68 /*
69 * Allow power off when OSI has been successfully enabled.
70 * On a PREEMPT_RT based configuration the domain idle states are
71 * supported, but only during system-wide suspend.
72 */
73 if (use_osi) {
74 pd->power_off = psci_pd_power_off;
75 if (IS_ENABLED(CONFIG_PREEMPT_RT))
76 pd->flags |= GENPD_FLAG_RPM_ALWAYS_ON;
77 } else {
78 pd->flags |= GENPD_FLAG_ALWAYS_ON;
79 }
80
81 /* Use governor for CPU PM domains if it has some states to manage. */
82 pd_gov = pd->states ? &pm_domain_cpu_gov : NULL;
83
84 ret = pm_genpd_init(pd, pd_gov, false);
85 if (ret)
86 goto free_pd_prov;
87
88 ret = of_genpd_add_provider_simple(np, pd);
89 if (ret)
90 goto remove_pd;
91
92 pd_provider->node = of_node_get(np);
93 list_add(&pd_provider->link, &psci_pd_providers);
94
95 pr_debug("init PM domain %s\n", pd->name);
96 return 0;
97
98 remove_pd:
99 pm_genpd_remove(pd);
100 free_pd_prov:
101 kfree(pd_provider);
102 free_pd:
103 dt_idle_pd_free(pd);
104 out:
105 pr_err("failed to init PM domain ret=%d %pOF\n", ret, np);
106 return ret;
107 }
108
psci_pd_remove(void)109 static void psci_pd_remove(void)
110 {
111 struct psci_pd_provider *pd_provider, *it;
112 struct generic_pm_domain *genpd;
113
114 list_for_each_entry_safe_reverse(pd_provider, it,
115 &psci_pd_providers, link) {
116 of_genpd_del_provider(pd_provider->node);
117
118 genpd = of_genpd_remove_last(pd_provider->node);
119 if (!IS_ERR(genpd))
120 kfree(genpd);
121
122 of_node_put(pd_provider->node);
123 list_del(&pd_provider->link);
124 kfree(pd_provider);
125 }
126 }
127
psci_cpuidle_domain_sync_state(struct device * dev)128 static void psci_cpuidle_domain_sync_state(struct device *dev)
129 {
130 /*
131 * All devices have now been attached/probed to the PM domain topology,
132 * hence it's fine to allow domain states to be picked.
133 */
134 psci_pd_allow_domain_state = true;
135 }
136
137 static const struct of_device_id psci_of_match[] = {
138 { .compatible = "arm,psci-1.0" },
139 {}
140 };
141
psci_cpuidle_domain_probe(struct platform_device * pdev)142 static int psci_cpuidle_domain_probe(struct platform_device *pdev)
143 {
144 struct device_node *np = pdev->dev.of_node;
145 bool use_osi = psci_has_osi_support();
146 int ret = 0, pd_count = 0;
147
148 if (!np)
149 return -ENODEV;
150
151 /*
152 * Parse child nodes for the "#power-domain-cells" property and
153 * initialize a genpd/genpd-of-provider pair when it's found.
154 */
155 for_each_child_of_node_scoped(np, node) {
156 if (!of_property_present(node, "#power-domain-cells"))
157 continue;
158
159 ret = psci_pd_init(node, use_osi);
160 if (ret)
161 goto exit;
162
163 pd_count++;
164 }
165
166 /* Bail out if not using the hierarchical CPU topology. */
167 if (!pd_count)
168 return 0;
169
170 /* Link genpd masters/subdomains to model the CPU topology. */
171 ret = dt_idle_pd_init_topology(np);
172 if (ret)
173 goto remove_pd;
174
175 /* let's try to enable OSI. */
176 ret = psci_set_osi_mode(use_osi);
177 if (ret)
178 goto remove_pd;
179
180 pr_info("Initialized CPU PM domain topology using %s mode\n",
181 use_osi ? "OSI" : "PC");
182 return 0;
183
184 remove_pd:
185 dt_idle_pd_remove_topology(np);
186 psci_pd_remove();
187 exit:
188 pr_err("failed to create CPU PM domains ret=%d\n", ret);
189 return ret;
190 }
191
192 static struct platform_driver psci_cpuidle_domain_driver = {
193 .probe = psci_cpuidle_domain_probe,
194 .driver = {
195 .name = "psci-cpuidle-domain",
196 .of_match_table = psci_of_match,
197 .sync_state = psci_cpuidle_domain_sync_state,
198 },
199 };
200
psci_idle_init_domains(void)201 static int __init psci_idle_init_domains(void)
202 {
203 return platform_driver_register(&psci_cpuidle_domain_driver);
204 }
205 core_initcall(psci_idle_init_domains);
206