1 // SPDX-License-Identifier: GPL-2.0
2 //
3 // Exynos Generic power domain support.
4 //
5 // Copyright (c) 2012 Samsung Electronics Co., Ltd.
6 // http://www.samsung.com
7 //
8 // Implementation of Exynos specific power domain control which is used in
9 // conjunction with runtime-pm. Support for both device-tree and non-device-tree
10 // based power domain support is included.
11
12 #include <linux/io.h>
13 #include <linux/err.h>
14 #include <linux/platform_device.h>
15 #include <linux/slab.h>
16 #include <linux/pm_domain.h>
17 #include <linux/delay.h>
18 #include <linux/of.h>
19 #include <linux/of_address.h>
20 #include <linux/pm_runtime.h>
21
22 struct exynos_pm_domain_config {
23 /* Value for LOCAL_PWR_CFG and STATUS fields for each domain */
24 u32 local_pwr_cfg;
25 };
26
27 /*
28 * Exynos specific wrapper around the generic power domain
29 */
30 struct exynos_pm_domain {
31 void __iomem *base;
32 struct generic_pm_domain pd;
33 u32 local_pwr_cfg;
34 };
35
exynos_pd_power(struct generic_pm_domain * domain,bool power_on)36 static int exynos_pd_power(struct generic_pm_domain *domain, bool power_on)
37 {
38 struct exynos_pm_domain *pd;
39 void __iomem *base;
40 u32 timeout, pwr;
41 char *op;
42
43 pd = container_of(domain, struct exynos_pm_domain, pd);
44 base = pd->base;
45
46 pwr = power_on ? pd->local_pwr_cfg : 0;
47 writel_relaxed(pwr, base);
48
49 /* Wait max 1ms */
50 timeout = 10;
51
52 while ((readl_relaxed(base + 0x4) & pd->local_pwr_cfg) != pwr) {
53 if (!timeout) {
54 op = (power_on) ? "enable" : "disable";
55 pr_err("Power domain %s %s failed\n", domain->name, op);
56 return -ETIMEDOUT;
57 }
58 timeout--;
59 cpu_relax();
60 usleep_range(80, 100);
61 }
62
63 return 0;
64 }
65
exynos_pd_power_on(struct generic_pm_domain * domain)66 static int exynos_pd_power_on(struct generic_pm_domain *domain)
67 {
68 return exynos_pd_power(domain, true);
69 }
70
exynos_pd_power_off(struct generic_pm_domain * domain)71 static int exynos_pd_power_off(struct generic_pm_domain *domain)
72 {
73 return exynos_pd_power(domain, false);
74 }
75
76 static const struct exynos_pm_domain_config exynos4210_cfg = {
77 .local_pwr_cfg = 0x7,
78 };
79
80 static const struct exynos_pm_domain_config exynos5433_cfg = {
81 .local_pwr_cfg = 0xf,
82 };
83
84 static const struct of_device_id exynos_pm_domain_of_match[] = {
85 {
86 .compatible = "samsung,exynos4210-pd",
87 .data = &exynos4210_cfg,
88 }, {
89 .compatible = "samsung,exynos5433-pd",
90 .data = &exynos5433_cfg,
91 },
92 { },
93 };
94
exynos_get_domain_name(struct device_node * node)95 static const char *exynos_get_domain_name(struct device_node *node)
96 {
97 const char *name;
98
99 if (of_property_read_string(node, "label", &name) < 0)
100 name = kbasename(node->full_name);
101 return kstrdup_const(name, GFP_KERNEL);
102 }
103
exynos_pd_probe(struct platform_device * pdev)104 static int exynos_pd_probe(struct platform_device *pdev)
105 {
106 const struct exynos_pm_domain_config *pm_domain_cfg;
107 struct device *dev = &pdev->dev;
108 struct device_node *np = dev->of_node;
109 struct of_phandle_args child, parent;
110 struct exynos_pm_domain *pd;
111 int on, ret;
112
113 pm_domain_cfg = of_device_get_match_data(dev);
114 pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
115 if (!pd)
116 return -ENOMEM;
117
118 pd->pd.name = exynos_get_domain_name(np);
119 if (!pd->pd.name)
120 return -ENOMEM;
121
122 pd->base = of_iomap(np, 0);
123 if (!pd->base) {
124 kfree_const(pd->pd.name);
125 return -ENODEV;
126 }
127
128 pd->pd.power_off = exynos_pd_power_off;
129 pd->pd.power_on = exynos_pd_power_on;
130 pd->local_pwr_cfg = pm_domain_cfg->local_pwr_cfg;
131
132 on = readl_relaxed(pd->base + 0x4) & pd->local_pwr_cfg;
133
134 pm_genpd_init(&pd->pd, NULL, !on);
135 ret = of_genpd_add_provider_simple(np, &pd->pd);
136
137 if (ret == 0 && of_parse_phandle_with_args(np, "power-domains",
138 "#power-domain-cells", 0, &parent) == 0) {
139 child.np = np;
140 child.args_count = 0;
141
142 if (of_genpd_add_subdomain(&parent, &child))
143 pr_warn("%pOF failed to add subdomain: %pOF\n",
144 parent.np, child.np);
145 else
146 pr_info("%pOF has as child subdomain: %pOF.\n",
147 parent.np, child.np);
148 }
149
150 pm_runtime_enable(dev);
151 return ret;
152 }
153
154 static struct platform_driver exynos_pd_driver = {
155 .probe = exynos_pd_probe,
156 .driver = {
157 .name = "exynos-pd",
158 .of_match_table = exynos_pm_domain_of_match,
159 .suppress_bind_attrs = true,
160 }
161 };
162
exynos4_pm_init_power_domain(void)163 static __init int exynos4_pm_init_power_domain(void)
164 {
165 return platform_driver_register(&exynos_pd_driver);
166 }
167 core_initcall(exynos4_pm_init_power_domain);
168