1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * SCMI Generic power domain support.
4  *
5  * Copyright (C) 2018-2021 ARM Ltd.
6  */
7 
8 #include <linux/err.h>
9 #include <linux/io.h>
10 #include <linux/module.h>
11 #include <linux/pm_domain.h>
12 #include <linux/scmi_protocol.h>
13 
14 static const struct scmi_power_proto_ops *power_ops;
15 
16 struct scmi_pm_domain {
17 	struct generic_pm_domain genpd;
18 	const struct scmi_protocol_handle *ph;
19 	const char *name;
20 	u32 domain;
21 };
22 
23 #define to_scmi_pd(gpd) container_of(gpd, struct scmi_pm_domain, genpd)
24 
scmi_pd_power(struct generic_pm_domain * domain,bool power_on)25 static int scmi_pd_power(struct generic_pm_domain *domain, bool power_on)
26 {
27 	int ret;
28 	u32 state, ret_state;
29 	struct scmi_pm_domain *pd = to_scmi_pd(domain);
30 
31 	if (power_on)
32 		state = SCMI_POWER_STATE_GENERIC_ON;
33 	else
34 		state = SCMI_POWER_STATE_GENERIC_OFF;
35 
36 	ret = power_ops->state_set(pd->ph, pd->domain, state);
37 	if (!ret)
38 		ret = power_ops->state_get(pd->ph, pd->domain, &ret_state);
39 	if (!ret && state != ret_state)
40 		return -EIO;
41 
42 	return ret;
43 }
44 
scmi_pd_power_on(struct generic_pm_domain * domain)45 static int scmi_pd_power_on(struct generic_pm_domain *domain)
46 {
47 	return scmi_pd_power(domain, true);
48 }
49 
scmi_pd_power_off(struct generic_pm_domain * domain)50 static int scmi_pd_power_off(struct generic_pm_domain *domain)
51 {
52 	return scmi_pd_power(domain, false);
53 }
54 
scmi_pm_domain_probe(struct scmi_device * sdev)55 static int scmi_pm_domain_probe(struct scmi_device *sdev)
56 {
57 	int num_domains, i;
58 	struct device *dev = &sdev->dev;
59 	struct device_node *np = dev->of_node;
60 	struct scmi_pm_domain *scmi_pd;
61 	struct genpd_onecell_data *scmi_pd_data;
62 	struct generic_pm_domain **domains;
63 	const struct scmi_handle *handle = sdev->handle;
64 	struct scmi_protocol_handle *ph;
65 
66 	if (!handle)
67 		return -ENODEV;
68 
69 	power_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_POWER, &ph);
70 	if (IS_ERR(power_ops))
71 		return PTR_ERR(power_ops);
72 
73 	num_domains = power_ops->num_domains_get(ph);
74 	if (num_domains < 0) {
75 		dev_err(dev, "number of domains not found\n");
76 		return num_domains;
77 	}
78 
79 	scmi_pd = devm_kcalloc(dev, num_domains, sizeof(*scmi_pd), GFP_KERNEL);
80 	if (!scmi_pd)
81 		return -ENOMEM;
82 
83 	scmi_pd_data = devm_kzalloc(dev, sizeof(*scmi_pd_data), GFP_KERNEL);
84 	if (!scmi_pd_data)
85 		return -ENOMEM;
86 
87 	domains = devm_kcalloc(dev, num_domains, sizeof(*domains), GFP_KERNEL);
88 	if (!domains)
89 		return -ENOMEM;
90 
91 	for (i = 0; i < num_domains; i++, scmi_pd++) {
92 		u32 state;
93 
94 		if (power_ops->state_get(ph, i, &state)) {
95 			dev_warn(dev, "failed to get state for domain %d\n", i);
96 			continue;
97 		}
98 
99 		scmi_pd->domain = i;
100 		scmi_pd->ph = ph;
101 		scmi_pd->name = power_ops->name_get(ph, i);
102 		scmi_pd->genpd.name = scmi_pd->name;
103 		scmi_pd->genpd.power_off = scmi_pd_power_off;
104 		scmi_pd->genpd.power_on = scmi_pd_power_on;
105 
106 		pm_genpd_init(&scmi_pd->genpd, NULL,
107 			      state == SCMI_POWER_STATE_GENERIC_OFF);
108 
109 		domains[i] = &scmi_pd->genpd;
110 	}
111 
112 	scmi_pd_data->domains = domains;
113 	scmi_pd_data->num_domains = num_domains;
114 
115 	dev_set_drvdata(dev, scmi_pd_data);
116 
117 	return of_genpd_add_provider_onecell(np, scmi_pd_data);
118 }
119 
scmi_pm_domain_remove(struct scmi_device * sdev)120 static void scmi_pm_domain_remove(struct scmi_device *sdev)
121 {
122 	int i;
123 	struct genpd_onecell_data *scmi_pd_data;
124 	struct device *dev = &sdev->dev;
125 	struct device_node *np = dev->of_node;
126 
127 	of_genpd_del_provider(np);
128 
129 	scmi_pd_data = dev_get_drvdata(dev);
130 	for (i = 0; i < scmi_pd_data->num_domains; i++) {
131 		if (!scmi_pd_data->domains[i])
132 			continue;
133 		pm_genpd_remove(scmi_pd_data->domains[i]);
134 	}
135 }
136 
137 static const struct scmi_device_id scmi_id_table[] = {
138 	{ SCMI_PROTOCOL_POWER, "genpd" },
139 	{ },
140 };
141 MODULE_DEVICE_TABLE(scmi, scmi_id_table);
142 
143 static struct scmi_driver scmi_power_domain_driver = {
144 	.name = "scmi-power-domain",
145 	.probe = scmi_pm_domain_probe,
146 	.remove = scmi_pm_domain_remove,
147 	.id_table = scmi_id_table,
148 };
149 module_scmi_driver(scmi_power_domain_driver);
150 
151 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
152 MODULE_DESCRIPTION("ARM SCMI power domain driver");
153 MODULE_LICENSE("GPL v2");
154