1 // SPDX-License-Identifier: GPL-2.0
3 * PM domains for CPUs via genpd - managed by cpuidle-psci.
5 * Copyright (C) 2019 Linaro Ltd.
6 * Author: Ulf Hansson <ulf.hansson@linaro.org>
10 #define pr_fmt(fmt) "CPUidle PSCI: " fmt
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>
22 #include "cpuidle-psci.h"
24 struct psci_pd_provider {
25 struct list_head link;
26 struct device_node *node;
29 static LIST_HEAD(psci_pd_providers);
30 static bool psci_pd_allow_domain_state;
32 static int psci_pd_power_off(struct generic_pm_domain *pd)
34 struct genpd_power_state *state = &pd->states[pd->state_idx];
40 if (!psci_pd_allow_domain_state)
43 /* OSI mode is enabled, set the corresponding domain state. */
44 pd_state = state->data;
45 psci_set_domain_state(*pd_state);
50 static int psci_pd_parse_state_nodes(struct genpd_power_state *states,
54 u32 psci_state, *psci_state_buf;
56 for (i = 0; i < state_count; i++) {
57 ret = psci_dt_parse_state_node(to_of_node(states[i].fwnode),
62 psci_state_buf = kmalloc(sizeof(u32), GFP_KERNEL);
63 if (!psci_state_buf) {
67 *psci_state_buf = psci_state;
68 states[i].data = psci_state_buf;
76 kfree(states[i].data);
80 static int psci_pd_parse_states(struct device_node *np,
81 struct genpd_power_state **states, int *state_count)
85 /* Parse the domain idle states. */
86 ret = of_genpd_parse_idle_states(np, states, state_count);
90 /* Fill out the PSCI specifics for each found state. */
91 ret = psci_pd_parse_state_nodes(*states, *state_count);
98 static void psci_pd_free_states(struct genpd_power_state *states,
99 unsigned int state_count)
103 for (i = 0; i < state_count; i++)
104 kfree(states[i].data);
108 static int psci_pd_init(struct device_node *np)
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;
116 pd = kzalloc(sizeof(*pd), GFP_KERNEL);
120 pd_provider = kzalloc(sizeof(*pd_provider), GFP_KERNEL);
124 pd->name = kasprintf(GFP_KERNEL, "%pOF", np);
129 * Parse the domain idle states and let genpd manage the state selection
130 * for those being compatible with "domain-idle-state".
132 ret = psci_pd_parse_states(np, &states, &state_count);
136 pd->free_states = psci_pd_free_states;
137 pd->name = kbasename(pd->name);
138 pd->power_off = psci_pd_power_off;
140 pd->state_count = state_count;
141 pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN;
143 /* Use governor for CPU PM domains if it has some states to manage. */
144 pd_gov = state_count > 0 ? &pm_domain_cpu_gov : NULL;
146 ret = pm_genpd_init(pd, pd_gov, false);
148 psci_pd_free_states(states, state_count);
152 ret = of_genpd_add_provider_simple(np, pd);
156 pd_provider->node = of_node_get(np);
157 list_add(&pd_provider->link, &psci_pd_providers);
159 pr_debug("init PM domain %s\n", pd->name);
171 pr_err("failed to init PM domain ret=%d %pOF\n", ret, np);
175 static void psci_pd_remove(void)
177 struct psci_pd_provider *pd_provider, *it;
178 struct generic_pm_domain *genpd;
180 list_for_each_entry_safe(pd_provider, it, &psci_pd_providers, link) {
181 of_genpd_del_provider(pd_provider->node);
183 genpd = of_genpd_remove_last(pd_provider->node);
187 of_node_put(pd_provider->node);
188 list_del(&pd_provider->link);
193 static int psci_pd_init_topology(struct device_node *np, bool add)
195 struct device_node *node;
196 struct of_phandle_args child, parent;
199 for_each_child_of_node(np, node) {
200 if (of_parse_phandle_with_args(node, "power-domains",
201 "#power-domain-cells", 0, &parent))
205 child.args_count = 0;
207 ret = add ? of_genpd_add_subdomain(&parent, &child) :
208 of_genpd_remove_subdomain(&parent, &child);
209 of_node_put(parent.np);
219 static int psci_pd_add_topology(struct device_node *np)
221 return psci_pd_init_topology(np, true);
224 static void psci_pd_remove_topology(struct device_node *np)
226 psci_pd_init_topology(np, false);
229 static void psci_cpuidle_domain_sync_state(struct device *dev)
232 * All devices have now been attached/probed to the PM domain topology,
233 * hence it's fine to allow domain states to be picked.
235 psci_pd_allow_domain_state = true;
238 static const struct of_device_id psci_of_match[] = {
239 { .compatible = "arm,psci-1.0" },
243 static int psci_cpuidle_domain_probe(struct platform_device *pdev)
245 struct device_node *np = pdev->dev.of_node;
246 struct device_node *node;
247 int ret = 0, pd_count = 0;
252 /* Currently limit the hierarchical topology to be used in OSI mode. */
253 if (!psci_has_osi_support())
257 * Parse child nodes for the "#power-domain-cells" property and
258 * initialize a genpd/genpd-of-provider pair when it's found.
260 for_each_child_of_node(np, node) {
261 if (!of_find_property(node, "#power-domain-cells", NULL))
264 ret = psci_pd_init(node);
271 /* Bail out if not using the hierarchical CPU topology. */
275 /* Link genpd masters/subdomains to model the CPU topology. */
276 ret = psci_pd_add_topology(np);
280 /* Try to enable OSI mode. */
281 ret = psci_set_osi_mode();
283 pr_warn("failed to enable OSI mode: %d\n", ret);
284 psci_pd_remove_topology(np);
288 pr_info("Initialized CPU PM domain topology\n");
296 pr_err("failed to create CPU PM domains ret=%d\n", ret);
300 static struct platform_driver psci_cpuidle_domain_driver = {
301 .probe = psci_cpuidle_domain_probe,
303 .name = "psci-cpuidle-domain",
304 .of_match_table = psci_of_match,
305 .sync_state = psci_cpuidle_domain_sync_state,
309 static int __init psci_idle_init_domains(void)
311 return platform_driver_register(&psci_cpuidle_domain_driver);
313 subsys_initcall(psci_idle_init_domains);
315 struct device *psci_dt_attach_cpu(int cpu)
319 dev = dev_pm_domain_attach_by_name(get_cpu_device(cpu), "psci");
320 if (IS_ERR_OR_NULL(dev))
323 pm_runtime_irq_safe(dev);
325 pm_runtime_get_sync(dev);
330 void psci_dt_detach_cpu(struct device *dev)
332 if (IS_ERR_OR_NULL(dev))
335 dev_pm_domain_detach(dev, false);