1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Exynos generic interconnect provider driver
4  *
5  * Copyright (c) 2020 Samsung Electronics Co., Ltd.
6  *
7  * Authors: Artur Świgoń <a.swigon@samsung.com>
8  *          Sylwester Nawrocki <s.nawrocki@samsung.com>
9  */
10 #include <linux/device.h>
11 #include <linux/interconnect-provider.h>
12 #include <linux/module.h>
13 #include <linux/of.h>
14 #include <linux/platform_device.h>
15 #include <linux/pm_qos.h>
16 #include <linux/slab.h>
17 
18 #define EXYNOS_ICC_DEFAULT_BUS_CLK_RATIO	8
19 
20 struct exynos_icc_priv {
21 	struct device *dev;
22 
23 	/* One interconnect node per provider */
24 	struct icc_provider provider;
25 	struct icc_node *node;
26 
27 	struct dev_pm_qos_request qos_req;
28 	u32 bus_clk_ratio;
29 };
30 
31 static struct icc_node *exynos_icc_get_parent(struct device_node *np)
32 {
33 	struct of_phandle_args args;
34 	struct icc_node_data *icc_node_data;
35 	struct icc_node *icc_node;
36 	int num, ret;
37 
38 	num = of_count_phandle_with_args(np, "interconnects",
39 					 "#interconnect-cells");
40 	if (num < 1)
41 		return NULL; /* parent nodes are optional */
42 
43 	/* Get the interconnect target node */
44 	ret = of_parse_phandle_with_args(np, "interconnects",
45 					"#interconnect-cells", 0, &args);
46 	if (ret < 0)
47 		return ERR_PTR(ret);
48 
49 	icc_node_data = of_icc_get_from_provider(&args);
50 	of_node_put(args.np);
51 
52 	if (IS_ERR(icc_node_data))
53 		return ERR_CAST(icc_node_data);
54 
55 	icc_node = icc_node_data->node;
56 	kfree(icc_node_data);
57 
58 	return icc_node;
59 }
60 
61 static int exynos_generic_icc_set(struct icc_node *src, struct icc_node *dst)
62 {
63 	struct exynos_icc_priv *src_priv = src->data, *dst_priv = dst->data;
64 	s32 src_freq = max(src->avg_bw, src->peak_bw) / src_priv->bus_clk_ratio;
65 	s32 dst_freq = max(dst->avg_bw, dst->peak_bw) / dst_priv->bus_clk_ratio;
66 	int ret;
67 
68 	ret = dev_pm_qos_update_request(&src_priv->qos_req, src_freq);
69 	if (ret < 0) {
70 		dev_err(src_priv->dev, "failed to update PM QoS of %s (src)\n",
71 			src->name);
72 		return ret;
73 	}
74 
75 	ret = dev_pm_qos_update_request(&dst_priv->qos_req, dst_freq);
76 	if (ret < 0) {
77 		dev_err(dst_priv->dev, "failed to update PM QoS of %s (dst)\n",
78 			dst->name);
79 		return ret;
80 	}
81 
82 	return 0;
83 }
84 
85 static struct icc_node *exynos_generic_icc_xlate(struct of_phandle_args *spec,
86 						 void *data)
87 {
88 	struct exynos_icc_priv *priv = data;
89 
90 	if (spec->np != priv->dev->parent->of_node)
91 		return ERR_PTR(-EINVAL);
92 
93 	return priv->node;
94 }
95 
96 static int exynos_generic_icc_remove(struct platform_device *pdev)
97 {
98 	struct exynos_icc_priv *priv = platform_get_drvdata(pdev);
99 
100 	icc_provider_deregister(&priv->provider);
101 	icc_nodes_remove(&priv->provider);
102 
103 	return 0;
104 }
105 
106 static int exynos_generic_icc_probe(struct platform_device *pdev)
107 {
108 	struct device *bus_dev = pdev->dev.parent;
109 	struct exynos_icc_priv *priv;
110 	struct icc_provider *provider;
111 	struct icc_node *icc_node, *icc_parent_node;
112 	int ret;
113 
114 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
115 	if (!priv)
116 		return -ENOMEM;
117 
118 	priv->dev = &pdev->dev;
119 	platform_set_drvdata(pdev, priv);
120 
121 	provider = &priv->provider;
122 
123 	provider->set = exynos_generic_icc_set;
124 	provider->aggregate = icc_std_aggregate;
125 	provider->xlate = exynos_generic_icc_xlate;
126 	provider->dev = bus_dev;
127 	provider->inter_set = true;
128 	provider->data = priv;
129 
130 	icc_provider_init(provider);
131 
132 	icc_node = icc_node_create(pdev->id);
133 	if (IS_ERR(icc_node))
134 		return PTR_ERR(icc_node);
135 
136 	priv->node = icc_node;
137 	icc_node->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%pOFn",
138 					bus_dev->of_node);
139 	if (of_property_read_u32(bus_dev->of_node, "samsung,data-clock-ratio",
140 				 &priv->bus_clk_ratio))
141 		priv->bus_clk_ratio = EXYNOS_ICC_DEFAULT_BUS_CLK_RATIO;
142 
143 	icc_node->data = priv;
144 	icc_node_add(icc_node, provider);
145 
146 	/*
147 	 * Register a PM QoS request for the parent (devfreq) device.
148 	 */
149 	ret = dev_pm_qos_add_request(bus_dev, &priv->qos_req,
150 				     DEV_PM_QOS_MIN_FREQUENCY, 0);
151 	if (ret < 0)
152 		goto err_node_del;
153 
154 	icc_parent_node = exynos_icc_get_parent(bus_dev->of_node);
155 	if (IS_ERR(icc_parent_node)) {
156 		ret = PTR_ERR(icc_parent_node);
157 		goto err_pmqos_del;
158 	}
159 	if (icc_parent_node) {
160 		ret = icc_link_create(icc_node, icc_parent_node->id);
161 		if (ret < 0)
162 			goto err_pmqos_del;
163 	}
164 
165 	ret = icc_provider_register(provider);
166 	if (ret < 0)
167 		goto err_pmqos_del;
168 
169 	return 0;
170 
171 err_pmqos_del:
172 	dev_pm_qos_remove_request(&priv->qos_req);
173 err_node_del:
174 	icc_nodes_remove(provider);
175 
176 	return ret;
177 }
178 
179 static struct platform_driver exynos_generic_icc_driver = {
180 	.driver = {
181 		.name = "exynos-generic-icc",
182 		.sync_state = icc_sync_state,
183 	},
184 	.probe = exynos_generic_icc_probe,
185 	.remove = exynos_generic_icc_remove,
186 };
187 module_platform_driver(exynos_generic_icc_driver);
188 
189 MODULE_DESCRIPTION("Exynos generic interconnect driver");
190 MODULE_AUTHOR("Artur Świgoń <a.swigon@samsung.com>");
191 MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki@samsung.com>");
192 MODULE_LICENSE("GPL v2");
193 MODULE_ALIAS("platform:exynos-generic-icc");
194