exynos.c

  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(const 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 void 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
104static int exynos_generic_icc_probe(struct platform_device *pdev)
105{
106	struct device *bus_dev = pdev->dev.parent;
107	struct exynos_icc_priv *priv;
108	struct icc_provider *provider;
109	struct icc_node *icc_node, *icc_parent_node;
110	int ret;
111
112	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
113	if (!priv)
114		return -ENOMEM;
115
116	priv->dev = &pdev->dev;
117	platform_set_drvdata(pdev, priv);
118
119	provider = &priv->provider;
120
121	provider->set = exynos_generic_icc_set;
122	provider->aggregate = icc_std_aggregate;
123	provider->xlate = exynos_generic_icc_xlate;
124	provider->dev = bus_dev;
125	provider->inter_set = true;
126	provider->data = priv;
127
128	icc_provider_init(provider);
129
130	icc_node = icc_node_create(pdev->id);
131	if (IS_ERR(icc_node))
132		return PTR_ERR(icc_node);
133
134	priv->node = icc_node;
135	icc_node->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%pOFn",
136					bus_dev->of_node);
137	if (!icc_node->name) {
138		icc_node_destroy(pdev->id);
139		return -ENOMEM;
140	}
141
142	if (of_property_read_u32(bus_dev->of_node, "samsung,data-clock-ratio",
143				 &priv->bus_clk_ratio))
144		priv->bus_clk_ratio = EXYNOS_ICC_DEFAULT_BUS_CLK_RATIO;
145
146	icc_node->data = priv;
147	icc_node_add(icc_node, provider);
148
149	/*
150	 * Register a PM QoS request for the parent (devfreq) device.
151	 */
152	ret = dev_pm_qos_add_request(bus_dev, &priv->qos_req,
153				     DEV_PM_QOS_MIN_FREQUENCY, 0);
154	if (ret < 0)
155		goto err_node_del;
156
157	icc_parent_node = exynos_icc_get_parent(bus_dev->of_node);
158	if (IS_ERR(icc_parent_node)) {
159		ret = PTR_ERR(icc_parent_node);
160		goto err_pmqos_del;
161	}
162	if (icc_parent_node) {
163		ret = icc_link_create(icc_node, icc_parent_node->id);
164		if (ret < 0)
165			goto err_pmqos_del;
166	}
167
168	ret = icc_provider_register(provider);
169	if (ret < 0)
170		goto err_pmqos_del;
171
172	return 0;
173
174err_pmqos_del:
175	dev_pm_qos_remove_request(&priv->qos_req);
176err_node_del:
177	icc_nodes_remove(provider);
178
179	return ret;
180}
181
182static struct platform_driver exynos_generic_icc_driver = {
183	.driver = {
184		.name = "exynos-generic-icc",
185		.sync_state = icc_sync_state,
186	},
187	.probe = exynos_generic_icc_probe,
188	.remove = exynos_generic_icc_remove,
189};
190module_platform_driver(exynos_generic_icc_driver);
191
192MODULE_DESCRIPTION("Exynos generic interconnect driver");
193MODULE_AUTHOR("Artur Świgoń <a.swigon@samsung.com>");
194MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki@samsung.com>");
195MODULE_LICENSE("GPL v2");
196MODULE_ALIAS("platform:exynos-generic-icc");