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
20struct 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
31static 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
61static 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
85static 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
96static 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
106static 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
171err_pmqos_del:
172	dev_pm_qos_remove_request(&priv->qos_req);
173err_node_del:
174	icc_nodes_remove(provider);
175
176	return ret;
177}
178
179static 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};
187module_platform_driver(exynos_generic_icc_driver);
188
189MODULE_DESCRIPTION("Exynos generic interconnect driver");
190MODULE_AUTHOR("Artur Świgoń <a.swigon@samsung.com>");
191MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki@samsung.com>");
192MODULE_LICENSE("GPL v2");
193MODULE_ALIAS("platform:exynos-generic-icc");
194