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 <[email protected]>
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 pd->flags |= GENPD_FLAG_ACTIVE_WAKEUP;
76 if (IS_ENABLED(CONFIG_PREEMPT_RT))
77 pd->flags |= GENPD_FLAG_RPM_ALWAYS_ON;
78 } else {
79 pd->flags |= GENPD_FLAG_ALWAYS_ON;
80 }
81
82 /* Use governor for CPU PM domains if it has some states to manage. */
83 pd_gov = pd->states ? &pm_domain_cpu_gov : NULL;
84
85 ret = pm_genpd_init(pd, pd_gov, false);
86 if (ret)
87 goto free_pd_prov;
88
89 ret = of_genpd_add_provider_simple(np, pd);
90 if (ret)
91 goto remove_pd;
92
93 pd_provider->node = of_node_get(np);
94 list_add(&pd_provider->link, &psci_pd_providers);
95
96 pr_debug("init PM domain %s\n", pd->name);
97 return 0;
98
99 remove_pd:
100 pm_genpd_remove(pd);
101 free_pd_prov:
102 kfree(pd_provider);
103 free_pd:
104 dt_idle_pd_free(pd);
105 out:
106 pr_err("failed to init PM domain ret=%d %pOF\n", ret, np);
107 return ret;
108 }
109
psci_pd_remove(void)110 static void psci_pd_remove(void)
111 {
112 struct psci_pd_provider *pd_provider, *it;
113 struct generic_pm_domain *genpd;
114
115 list_for_each_entry_safe_reverse(pd_provider, it,
116 &psci_pd_providers, link) {
117 of_genpd_del_provider(pd_provider->node);
118
119 genpd = of_genpd_remove_last(pd_provider->node);
120 if (!IS_ERR(genpd))
121 kfree(genpd);
122
123 of_node_put(pd_provider->node);
124 list_del(&pd_provider->link);
125 kfree(pd_provider);
126 }
127 }
128
psci_cpuidle_domain_sync_state(struct device * dev)129 static void psci_cpuidle_domain_sync_state(struct device *dev)
130 {
131 /*
132 * All devices have now been attached/probed to the PM domain topology,
133 * hence it's fine to allow domain states to be picked.
134 */
135 psci_pd_allow_domain_state = true;
136 }
137
138 static const struct of_device_id psci_of_match[] = {
139 { .compatible = "arm,psci-1.0" },
140 {}
141 };
142
psci_cpuidle_domain_probe(struct platform_device * pdev)143 static int psci_cpuidle_domain_probe(struct platform_device *pdev)
144 {
145 struct device_node *np = pdev->dev.of_node;
146 bool use_osi = psci_has_osi_support();
147 int ret = 0, pd_count = 0;
148
149 if (!np)
150 return -ENODEV;
151
152 /*
153 * Parse child nodes for the "#power-domain-cells" property and
154 * initialize a genpd/genpd-of-provider pair when it's found.
155 */
156 for_each_child_of_node_scoped(np, node) {
157 if (!of_property_present(node, "#power-domain-cells"))
158 continue;
159
160 ret = psci_pd_init(node, use_osi);
161 if (ret)
162 goto exit;
163
164 pd_count++;
165 }
166
167 /* Bail out if not using the hierarchical CPU topology. */
168 if (!pd_count)
169 return 0;
170
171 /* Link genpd masters/subdomains to model the CPU topology. */
172 ret = dt_idle_pd_init_topology(np);
173 if (ret)
174 goto remove_pd;
175
176 /* let's try to enable OSI. */
177 ret = psci_set_osi_mode(use_osi);
178 if (ret)
179 goto remove_pd;
180
181 pr_info("Initialized CPU PM domain topology using %s mode\n",
182 use_osi ? "OSI" : "PC");
183 return 0;
184
185 remove_pd:
186 dt_idle_pd_remove_topology(np);
187 psci_pd_remove();
188 exit:
189 pr_err("failed to create CPU PM domains ret=%d\n", ret);
190 return ret;
191 }
192
193 static struct platform_driver psci_cpuidle_domain_driver = {
194 .probe = psci_cpuidle_domain_probe,
195 .driver = {
196 .name = "psci-cpuidle-domain",
197 .of_match_table = psci_of_match,
198 .sync_state = psci_cpuidle_domain_sync_state,
199 },
200 };
201
psci_idle_init_domains(void)202 static int __init psci_idle_init_domains(void)
203 {
204 return platform_driver_register(&psci_cpuidle_domain_driver);
205 }
206 core_initcall(psci_idle_init_domains);
207