1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
4  * Author: Lin Huang <hl@rock-chips.com>
5  */
6 
7 #include <linux/clk.h>
8 #include <linux/devfreq-event.h>
9 #include <linux/kernel.h>
10 #include <linux/err.h>
11 #include <linux/init.h>
12 #include <linux/io.h>
13 #include <linux/mfd/syscon.h>
14 #include <linux/module.h>
15 #include <linux/platform_device.h>
16 #include <linux/regmap.h>
17 #include <linux/slab.h>
18 #include <linux/list.h>
19 #include <linux/of.h>
20 
21 #include <soc/rockchip/rk3399_grf.h>
22 
23 #define RK3399_DMC_NUM_CH	2
24 
25 /* DDRMON_CTRL */
26 #define DDRMON_CTRL	0x04
27 #define CLR_DDRMON_CTRL	(0x1f0000 << 0)
28 #define LPDDR4_EN	(0x10001 << 4)
29 #define HARDWARE_EN	(0x10001 << 3)
30 #define LPDDR3_EN	(0x10001 << 2)
31 #define SOFTWARE_EN	(0x10001 << 1)
32 #define SOFTWARE_DIS	(0x10000 << 1)
33 #define TIME_CNT_EN	(0x10001 << 0)
34 
35 #define DDRMON_CH0_COUNT_NUM		0x28
36 #define DDRMON_CH0_DFI_ACCESS_NUM	0x2c
37 #define DDRMON_CH1_COUNT_NUM		0x3c
38 #define DDRMON_CH1_DFI_ACCESS_NUM	0x40
39 
40 struct dmc_usage {
41 	u32 access;
42 	u32 total;
43 };
44 
45 /*
46  * The dfi controller can monitor DDR load. It has an upper and lower threshold
47  * for the operating points. Whenever the usage leaves these bounds an event is
48  * generated to indicate the DDR frequency should be changed.
49  */
50 struct rockchip_dfi {
51 	struct devfreq_event_dev *edev;
52 	struct devfreq_event_desc *desc;
53 	struct dmc_usage ch_usage[RK3399_DMC_NUM_CH];
54 	struct device *dev;
55 	void __iomem *regs;
56 	struct regmap *regmap_pmu;
57 	struct clk *clk;
58 };
59 
60 static void rockchip_dfi_start_hardware_counter(struct devfreq_event_dev *edev)
61 {
62 	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
63 	void __iomem *dfi_regs = info->regs;
64 	u32 val;
65 	u32 ddr_type;
66 
67 	/* get ddr type */
68 	regmap_read(info->regmap_pmu, RK3399_PMUGRF_OS_REG2, &val);
69 	ddr_type = (val >> RK3399_PMUGRF_DDRTYPE_SHIFT) &
70 		    RK3399_PMUGRF_DDRTYPE_MASK;
71 
72 	/* clear DDRMON_CTRL setting */
73 	writel_relaxed(CLR_DDRMON_CTRL, dfi_regs + DDRMON_CTRL);
74 
75 	/* set ddr type to dfi */
76 	if (ddr_type == RK3399_PMUGRF_DDRTYPE_LPDDR3)
77 		writel_relaxed(LPDDR3_EN, dfi_regs + DDRMON_CTRL);
78 	else if (ddr_type == RK3399_PMUGRF_DDRTYPE_LPDDR4)
79 		writel_relaxed(LPDDR4_EN, dfi_regs + DDRMON_CTRL);
80 
81 	/* enable count, use software mode */
82 	writel_relaxed(SOFTWARE_EN, dfi_regs + DDRMON_CTRL);
83 }
84 
85 static void rockchip_dfi_stop_hardware_counter(struct devfreq_event_dev *edev)
86 {
87 	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
88 	void __iomem *dfi_regs = info->regs;
89 
90 	writel_relaxed(SOFTWARE_DIS, dfi_regs + DDRMON_CTRL);
91 }
92 
93 static int rockchip_dfi_get_busier_ch(struct devfreq_event_dev *edev)
94 {
95 	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
96 	u32 tmp, max = 0;
97 	u32 i, busier_ch = 0;
98 	void __iomem *dfi_regs = info->regs;
99 
100 	rockchip_dfi_stop_hardware_counter(edev);
101 
102 	/* Find out which channel is busier */
103 	for (i = 0; i < RK3399_DMC_NUM_CH; i++) {
104 		info->ch_usage[i].access = readl_relaxed(dfi_regs +
105 				DDRMON_CH0_DFI_ACCESS_NUM + i * 20) * 4;
106 		info->ch_usage[i].total = readl_relaxed(dfi_regs +
107 				DDRMON_CH0_COUNT_NUM + i * 20);
108 		tmp = info->ch_usage[i].access;
109 		if (tmp > max) {
110 			busier_ch = i;
111 			max = tmp;
112 		}
113 	}
114 	rockchip_dfi_start_hardware_counter(edev);
115 
116 	return busier_ch;
117 }
118 
119 static int rockchip_dfi_disable(struct devfreq_event_dev *edev)
120 {
121 	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
122 
123 	rockchip_dfi_stop_hardware_counter(edev);
124 	clk_disable_unprepare(info->clk);
125 
126 	return 0;
127 }
128 
129 static int rockchip_dfi_enable(struct devfreq_event_dev *edev)
130 {
131 	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
132 	int ret;
133 
134 	ret = clk_prepare_enable(info->clk);
135 	if (ret) {
136 		dev_err(&edev->dev, "failed to enable dfi clk: %d\n", ret);
137 		return ret;
138 	}
139 
140 	rockchip_dfi_start_hardware_counter(edev);
141 	return 0;
142 }
143 
144 static int rockchip_dfi_set_event(struct devfreq_event_dev *edev)
145 {
146 	return 0;
147 }
148 
149 static int rockchip_dfi_get_event(struct devfreq_event_dev *edev,
150 				  struct devfreq_event_data *edata)
151 {
152 	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
153 	int busier_ch;
154 
155 	busier_ch = rockchip_dfi_get_busier_ch(edev);
156 
157 	edata->load_count = info->ch_usage[busier_ch].access;
158 	edata->total_count = info->ch_usage[busier_ch].total;
159 
160 	return 0;
161 }
162 
163 static const struct devfreq_event_ops rockchip_dfi_ops = {
164 	.disable = rockchip_dfi_disable,
165 	.enable = rockchip_dfi_enable,
166 	.get_event = rockchip_dfi_get_event,
167 	.set_event = rockchip_dfi_set_event,
168 };
169 
170 static const struct of_device_id rockchip_dfi_id_match[] = {
171 	{ .compatible = "rockchip,rk3399-dfi" },
172 	{ },
173 };
174 MODULE_DEVICE_TABLE(of, rockchip_dfi_id_match);
175 
176 static int rockchip_dfi_probe(struct platform_device *pdev)
177 {
178 	struct device *dev = &pdev->dev;
179 	struct rockchip_dfi *data;
180 	struct devfreq_event_desc *desc;
181 	struct device_node *np = pdev->dev.of_node, *node;
182 
183 	data = devm_kzalloc(dev, sizeof(struct rockchip_dfi), GFP_KERNEL);
184 	if (!data)
185 		return -ENOMEM;
186 
187 	data->regs = devm_platform_ioremap_resource(pdev, 0);
188 	if (IS_ERR(data->regs))
189 		return PTR_ERR(data->regs);
190 
191 	data->clk = devm_clk_get(dev, "pclk_ddr_mon");
192 	if (IS_ERR(data->clk))
193 		return dev_err_probe(dev, PTR_ERR(data->clk),
194 				     "Cannot get the clk pclk_ddr_mon\n");
195 
196 	/* try to find the optional reference to the pmu syscon */
197 	node = of_parse_phandle(np, "rockchip,pmu", 0);
198 	if (node) {
199 		data->regmap_pmu = syscon_node_to_regmap(node);
200 		of_node_put(node);
201 		if (IS_ERR(data->regmap_pmu))
202 			return PTR_ERR(data->regmap_pmu);
203 	}
204 	data->dev = dev;
205 
206 	desc = devm_kzalloc(dev, sizeof(*desc), GFP_KERNEL);
207 	if (!desc)
208 		return -ENOMEM;
209 
210 	desc->ops = &rockchip_dfi_ops;
211 	desc->driver_data = data;
212 	desc->name = np->name;
213 	data->desc = desc;
214 
215 	data->edev = devm_devfreq_event_add_edev(&pdev->dev, desc);
216 	if (IS_ERR(data->edev)) {
217 		dev_err(&pdev->dev,
218 			"failed to add devfreq-event device\n");
219 		return PTR_ERR(data->edev);
220 	}
221 
222 	platform_set_drvdata(pdev, data);
223 
224 	return 0;
225 }
226 
227 static struct platform_driver rockchip_dfi_driver = {
228 	.probe	= rockchip_dfi_probe,
229 	.driver = {
230 		.name	= "rockchip-dfi",
231 		.of_match_table = rockchip_dfi_id_match,
232 	},
233 };
234 module_platform_driver(rockchip_dfi_driver);
235 
236 MODULE_LICENSE("GPL v2");
237 MODULE_AUTHOR("Lin Huang <hl@rock-chips.com>");
238 MODULE_DESCRIPTION("Rockchip DFI driver");
239