dt_idle_genpd.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * PM domains for CPUs via genpd.
  4 *
  5 * Copyright (C) 2019 Linaro Ltd.
  6 * Author: Ulf Hansson <ulf.hansson@linaro.org>
  7 *
  8 * Copyright (c) 2021 Western Digital Corporation or its affiliates.
  9 * Copyright (c) 2022 Ventana Micro Systems Inc.
 10 */
 11
 12#define pr_fmt(fmt) "dt-idle-genpd: " fmt
 13
 14#include <linux/cpu.h>
 15#include <linux/device.h>
 16#include <linux/kernel.h>
 17#include <linux/pm_domain.h>
 18#include <linux/pm_runtime.h>
 19#include <linux/slab.h>
 20#include <linux/string.h>
 21
 22#include "dt_idle_genpd.h"
 23
 24static int pd_parse_state_nodes(
 25			int (*parse_state)(struct device_node *, u32 *),
 26			struct genpd_power_state *states, int state_count)
 27{
 28	int i, ret;
 29	u32 state, *state_buf;
 30
 31	for (i = 0; i < state_count; i++) {
 32		ret = parse_state(to_of_node(states[i].fwnode), &state);
 33		if (ret)
 34			goto free_state;
 35
 36		state_buf = kmalloc(sizeof(u32), GFP_KERNEL);
 37		if (!state_buf) {
 38			ret = -ENOMEM;
 39			goto free_state;
 40		}
 41		*state_buf = state;
 42		states[i].data = state_buf;
 43	}
 44
 45	return 0;
 46
 47free_state:
 48	i--;
 49	for (; i >= 0; i--)
 50		kfree(states[i].data);
 51	return ret;
 52}
 53
 54static int pd_parse_states(struct device_node *np,
 55			   int (*parse_state)(struct device_node *, u32 *),
 56			   struct genpd_power_state **states,
 57			   int *state_count)
 58{
 59	int ret;
 60
 61	/* Parse the domain idle states. */
 62	ret = of_genpd_parse_idle_states(np, states, state_count);
 63	if (ret)
 64		return ret;
 65
 66	/* Fill out the dt specifics for each found state. */
 67	ret = pd_parse_state_nodes(parse_state, *states, *state_count);
 68	if (ret)
 69		kfree(*states);
 70
 71	return ret;
 72}
 73
 74static void pd_free_states(struct genpd_power_state *states,
 75			    unsigned int state_count)
 76{
 77	int i;
 78
 79	for (i = 0; i < state_count; i++)
 80		kfree(states[i].data);
 81	kfree(states);
 82}
 83
 84void dt_idle_pd_free(struct generic_pm_domain *pd)
 85{
 86	pd_free_states(pd->states, pd->state_count);
 87	kfree(pd->name);
 88	kfree(pd);
 89}
 90
 91struct generic_pm_domain *dt_idle_pd_alloc(struct device_node *np,
 92			int (*parse_state)(struct device_node *, u32 *))
 93{
 94	struct generic_pm_domain *pd;
 95	struct genpd_power_state *states = NULL;
 96	int ret, state_count = 0;
 97
 98	pd = kzalloc(sizeof(*pd), GFP_KERNEL);
 99	if (!pd)
100		goto out;
101
102	pd->name = kasprintf(GFP_KERNEL, "%pOF", np);
103	if (!pd->name)
104		goto free_pd;
105
106	/*
107	 * Parse the domain idle states and let genpd manage the state selection
108	 * for those being compatible with "domain-idle-state".
109	 */
110	ret = pd_parse_states(np, parse_state, &states, &state_count);
111	if (ret)
112		goto free_name;
113
114	pd->free_states = pd_free_states;
115	pd->name = kbasename(pd->name);
116	pd->states = states;
117	pd->state_count = state_count;
118
119	pr_debug("alloc PM domain %s\n", pd->name);
120	return pd;
121
122free_name:
123	kfree(pd->name);
124free_pd:
125	kfree(pd);
126out:
127	pr_err("failed to alloc PM domain %pOF\n", np);
128	return NULL;
129}
130
131int dt_idle_pd_init_topology(struct device_node *np)
132{
133	struct of_phandle_args child, parent;
134	int ret;
135
136	for_each_child_of_node_scoped(np, node) {
137		if (of_parse_phandle_with_args(node, "power-domains",
138					"#power-domain-cells", 0, &parent))
139			continue;
140
141		child.np = node;
142		child.args_count = 0;
143		ret = of_genpd_add_subdomain(&parent, &child);
144		of_node_put(parent.np);
145		if (ret)
146			return ret;
147	}
148
149	return 0;
150}
151
152int dt_idle_pd_remove_topology(struct device_node *np)
153{
154	struct of_phandle_args child, parent;
155	int ret;
156
157	for_each_child_of_node_scoped(np, node) {
158		if (of_parse_phandle_with_args(node, "power-domains",
159					"#power-domain-cells", 0, &parent))
160			continue;
161
162		child.np = node;
163		child.args_count = 0;
164		ret = of_genpd_remove_subdomain(&parent, &child);
165		of_node_put(parent.np);
166		if (ret)
167			return ret;
168	}
169
170	return 0;
171}
172
173struct device *dt_idle_attach_cpu(int cpu, const char *name)
174{
175	struct device *dev;
176
177	dev = dev_pm_domain_attach_by_name(get_cpu_device(cpu), name);
178	if (IS_ERR_OR_NULL(dev))
179		return dev;
180
181	pm_runtime_irq_safe(dev);
182	if (cpu_online(cpu))
183		pm_runtime_get_sync(dev);
184
185	dev_pm_syscore_device(dev, true);
186
187	return dev;
188}
189
190void dt_idle_detach_cpu(struct device *dev)
191{
192	if (IS_ERR_OR_NULL(dev))
193		return;
194
195	dev_pm_domain_detach(dev, false);
196}