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