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
24 struct psci_pd_provider {
25 struct list_head link;
26 struct device_node *node;
27 };
28
29 static LIST_HEAD(psci_pd_providers);
30 static bool psci_pd_allow_domain_state;
31
psci_pd_power_off(struct generic_pm_domain * pd)32 static 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 if (!psci_pd_allow_domain_state)
41 return -EBUSY;
42
43 /* OSI mode is enabled, set the corresponding domain state. */
44 pd_state = state->data;
45 psci_set_domain_state(*pd_state);
46
47 return 0;
48 }
49
psci_pd_parse_state_nodes(struct genpd_power_state * states,int state_count)50 static int psci_pd_parse_state_nodes(struct genpd_power_state *states,
51 int state_count)
52 {
53 int i, ret;
54 u32 psci_state, *psci_state_buf;
55
56 for (i = 0; i < state_count; i++) {
57 ret = psci_dt_parse_state_node(to_of_node(states[i].fwnode),
58 &psci_state);
59 if (ret)
60 goto free_state;
61
62 psci_state_buf = kmalloc(sizeof(u32), GFP_KERNEL);
63 if (!psci_state_buf) {
64 ret = -ENOMEM;
65 goto free_state;
66 }
67 *psci_state_buf = psci_state;
68 states[i].data = psci_state_buf;
69 }
70
71 return 0;
72
73 free_state:
74 i--;
75 for (; i >= 0; i--)
76 kfree(states[i].data);
77 return ret;
78 }
79
psci_pd_parse_states(struct device_node * np,struct genpd_power_state ** states,int * state_count)80 static int psci_pd_parse_states(struct device_node *np,
81 struct genpd_power_state **states, int *state_count)
82 {
83 int ret;
84
85 /* Parse the domain idle states. */
86 ret = of_genpd_parse_idle_states(np, states, state_count);
87 if (ret)
88 return ret;
89
90 /* Fill out the PSCI specifics for each found state. */
91 ret = psci_pd_parse_state_nodes(*states, *state_count);
92 if (ret)
93 kfree(*states);
94
95 return ret;
96 }
97
psci_pd_free_states(struct genpd_power_state * states,unsigned int state_count)98 static void psci_pd_free_states(struct genpd_power_state *states,
99 unsigned int state_count)
100 {
101 int i;
102
103 for (i = 0; i < state_count; i++)
104 kfree(states[i].data);
105 kfree(states);
106 }
107
psci_pd_init(struct device_node * np,bool use_osi)108 static int psci_pd_init(struct device_node *np, bool use_osi)
109 {
110 struct generic_pm_domain *pd;
111 struct psci_pd_provider *pd_provider;
112 struct dev_power_governor *pd_gov;
113 struct genpd_power_state *states = NULL;
114 int ret = -ENOMEM, state_count = 0;
115
116 pd = kzalloc(sizeof(*pd), GFP_KERNEL);
117 if (!pd)
118 goto out;
119
120 pd_provider = kzalloc(sizeof(*pd_provider), GFP_KERNEL);
121 if (!pd_provider)
122 goto free_pd;
123
124 pd->name = kasprintf(GFP_KERNEL, "%pOF", np);
125 if (!pd->name)
126 goto free_pd_prov;
127
128 /*
129 * Parse the domain idle states and let genpd manage the state selection
130 * for those being compatible with "domain-idle-state".
131 */
132 ret = psci_pd_parse_states(np, &states, &state_count);
133 if (ret)
134 goto free_name;
135
136 pd->free_states = psci_pd_free_states;
137 pd->name = kbasename(pd->name);
138 pd->states = states;
139 pd->state_count = state_count;
140 pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN;
141
142 /* Allow power off when OSI has been successfully enabled. */
143 if (use_osi)
144 pd->power_off = psci_pd_power_off;
145 else
146 pd->flags |= GENPD_FLAG_ALWAYS_ON;
147
148 /* Use governor for CPU PM domains if it has some states to manage. */
149 pd_gov = state_count > 0 ? &pm_domain_cpu_gov : NULL;
150
151 ret = pm_genpd_init(pd, pd_gov, false);
152 if (ret) {
153 psci_pd_free_states(states, state_count);
154 goto free_name;
155 }
156
157 ret = of_genpd_add_provider_simple(np, pd);
158 if (ret)
159 goto remove_pd;
160
161 pd_provider->node = of_node_get(np);
162 list_add(&pd_provider->link, &psci_pd_providers);
163
164 pr_debug("init PM domain %s\n", pd->name);
165 return 0;
166
167 remove_pd:
168 pm_genpd_remove(pd);
169 free_name:
170 kfree(pd->name);
171 free_pd_prov:
172 kfree(pd_provider);
173 free_pd:
174 kfree(pd);
175 out:
176 pr_err("failed to init PM domain ret=%d %pOF\n", ret, np);
177 return ret;
178 }
179
psci_pd_remove(void)180 static void psci_pd_remove(void)
181 {
182 struct psci_pd_provider *pd_provider, *it;
183 struct generic_pm_domain *genpd;
184
185 list_for_each_entry_safe_reverse(pd_provider, it,
186 &psci_pd_providers, link) {
187 of_genpd_del_provider(pd_provider->node);
188
189 genpd = of_genpd_remove_last(pd_provider->node);
190 if (!IS_ERR(genpd))
191 kfree(genpd);
192
193 of_node_put(pd_provider->node);
194 list_del(&pd_provider->link);
195 kfree(pd_provider);
196 }
197 }
198
psci_pd_init_topology(struct device_node * np)199 static int psci_pd_init_topology(struct device_node *np)
200 {
201 struct device_node *node;
202 struct of_phandle_args child, parent;
203 int ret;
204
205 for_each_child_of_node(np, node) {
206 if (of_parse_phandle_with_args(node, "power-domains",
207 "#power-domain-cells", 0, &parent))
208 continue;
209
210 child.np = node;
211 child.args_count = 0;
212 ret = of_genpd_add_subdomain(&parent, &child);
213 of_node_put(parent.np);
214 if (ret) {
215 of_node_put(node);
216 return ret;
217 }
218 }
219
220 return 0;
221 }
222
psci_pd_try_set_osi_mode(void)223 static bool psci_pd_try_set_osi_mode(void)
224 {
225 int ret;
226
227 if (!psci_has_osi_support())
228 return false;
229
230 ret = psci_set_osi_mode(true);
231 if (ret) {
232 pr_warn("failed to enable OSI mode: %d\n", ret);
233 return false;
234 }
235
236 return true;
237 }
238
psci_cpuidle_domain_sync_state(struct device * dev)239 static void psci_cpuidle_domain_sync_state(struct device *dev)
240 {
241 /*
242 * All devices have now been attached/probed to the PM domain topology,
243 * hence it's fine to allow domain states to be picked.
244 */
245 psci_pd_allow_domain_state = true;
246 }
247
248 static const struct of_device_id psci_of_match[] = {
249 { .compatible = "arm,psci-1.0" },
250 {}
251 };
252
psci_cpuidle_domain_probe(struct platform_device * pdev)253 static int psci_cpuidle_domain_probe(struct platform_device *pdev)
254 {
255 struct device_node *np = pdev->dev.of_node;
256 struct device_node *node;
257 bool use_osi;
258 int ret = 0, pd_count = 0;
259
260 if (!np)
261 return -ENODEV;
262
263 /* If OSI mode is supported, let's try to enable it. */
264 use_osi = psci_pd_try_set_osi_mode();
265
266 /*
267 * Parse child nodes for the "#power-domain-cells" property and
268 * initialize a genpd/genpd-of-provider pair when it's found.
269 */
270 for_each_child_of_node(np, node) {
271 if (!of_find_property(node, "#power-domain-cells", NULL))
272 continue;
273
274 ret = psci_pd_init(node, use_osi);
275 if (ret)
276 goto put_node;
277
278 pd_count++;
279 }
280
281 /* Bail out if not using the hierarchical CPU topology. */
282 if (!pd_count)
283 goto no_pd;
284
285 /* Link genpd masters/subdomains to model the CPU topology. */
286 ret = psci_pd_init_topology(np);
287 if (ret)
288 goto remove_pd;
289
290 pr_info("Initialized CPU PM domain topology\n");
291 return 0;
292
293 put_node:
294 of_node_put(node);
295 remove_pd:
296 psci_pd_remove();
297 pr_err("failed to create CPU PM domains ret=%d\n", ret);
298 no_pd:
299 if (use_osi)
300 psci_set_osi_mode(false);
301 return ret;
302 }
303
304 static struct platform_driver psci_cpuidle_domain_driver = {
305 .probe = psci_cpuidle_domain_probe,
306 .driver = {
307 .name = "psci-cpuidle-domain",
308 .of_match_table = psci_of_match,
309 .sync_state = psci_cpuidle_domain_sync_state,
310 },
311 };
312
psci_idle_init_domains(void)313 static int __init psci_idle_init_domains(void)
314 {
315 return platform_driver_register(&psci_cpuidle_domain_driver);
316 }
317 subsys_initcall(psci_idle_init_domains);
318
psci_dt_attach_cpu(int cpu)319 struct device *psci_dt_attach_cpu(int cpu)
320 {
321 struct device *dev;
322
323 dev = dev_pm_domain_attach_by_name(get_cpu_device(cpu), "psci");
324 if (IS_ERR_OR_NULL(dev))
325 return dev;
326
327 pm_runtime_irq_safe(dev);
328 if (cpu_online(cpu))
329 pm_runtime_get_sync(dev);
330
331 dev_pm_syscore_device(dev, true);
332
333 return dev;
334 }
335
psci_dt_detach_cpu(struct device * dev)336 void psci_dt_detach_cpu(struct device *dev)
337 {
338 if (IS_ERR_OR_NULL(dev))
339 return;
340
341 dev_pm_domain_detach(dev, false);
342 }
343