cpuidle-psci-domain.c

  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, pd->state_idx, *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, 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(pd, pd_gov, false);
 82	if (ret)
 83		goto free_pd_prov;
 84
 85	ret = of_genpd_add_provider_simple(np, pd);
 86	if (ret)
 87		goto remove_pd;
 88
 89	pd_provider->node = of_node_get(np);
 90	list_add(&pd_provider->link, &psci_pd_providers);
 91
 92	pr_debug("init PM domain %s\n", pd->name);
 93	return 0;
 94
 95remove_pd:
 96	pm_genpd_remove(pd);
 97free_pd_prov:
 98	kfree(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(pd_provider->node);
114
115		genpd = of_genpd_remove_last(pd_provider->node);
116		if (!IS_ERR(genpd))
117			kfree(genpd);
118
119		of_node_put(pd_provider->node);
120		list_del(&pd_provider->link);
121		kfree(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(node, "#power-domain-cells"))
145			continue;
146
147		ret = psci_pd_init(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(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);