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 device_node *node;
134	struct of_phandle_args child, parent;
135	int ret;
136
137	for_each_child_of_node(np, node) {
138		if (of_parse_phandle_with_args(node, "power-domains",
139					"#power-domain-cells", 0, &parent))
140			continue;
141
142		child.np = node;
143		child.args_count = 0;
144		ret = of_genpd_add_subdomain(&parent, &child);
145		of_node_put(parent.np);
146		if (ret) {
147			of_node_put(node);
148			return ret;
149		}
150	}
151
152	return 0;
153}
154
155int dt_idle_pd_remove_topology(struct device_node *np)
156{
157	struct device_node *node;
158	struct of_phandle_args child, parent;
159	int ret;
160
161	for_each_child_of_node(np, node) {
162		if (of_parse_phandle_with_args(node, "power-domains",
163					"#power-domain-cells", 0, &parent))
164			continue;
165
166		child.np = node;
167		child.args_count = 0;
168		ret = of_genpd_remove_subdomain(&parent, &child);
169		of_node_put(parent.np);
170		if (ret) {
171			of_node_put(node);
172			return ret;
173		}
174	}
175
176	return 0;
177}
178
179struct device *dt_idle_attach_cpu(int cpu, const char *name)
180{
181	struct device *dev;
182
183	dev = dev_pm_domain_attach_by_name(get_cpu_device(cpu), name);
184	if (IS_ERR_OR_NULL(dev))
185		return dev;
186
187	pm_runtime_irq_safe(dev);
188	if (cpu_online(cpu))
189		pm_runtime_get_sync(dev);
190
191	dev_pm_syscore_device(dev, true);
192
193	return dev;
194}
195
196void dt_idle_detach_cpu(struct device *dev)
197{
198	if (IS_ERR_OR_NULL(dev))
199		return;
200
201	dev_pm_domain_detach(dev, false);
202}
203