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
 40struct 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 */
 50struct 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
 60static 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
 85static 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
 93static 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
119static 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
129static 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
144static int rockchip_dfi_set_event(struct devfreq_event_dev *edev)
145{
146	return 0;
147}
148
149static 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
163static 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
170static const struct of_device_id rockchip_dfi_id_match[] = {
171	{ .compatible = "rockchip,rk3399-dfi" },
172	{ },
173};
174MODULE_DEVICE_TABLE(of, rockchip_dfi_id_match);
175
176static 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		dev_err(dev, "Cannot get the clk dmc_clk\n");
194		return PTR_ERR(data->clk);
195	}
196
197	/* try to find the optional reference to the pmu syscon */
198	node = of_parse_phandle(np, "rockchip,pmu", 0);
199	if (node) {
200		data->regmap_pmu = syscon_node_to_regmap(node);
201		of_node_put(node);
202		if (IS_ERR(data->regmap_pmu))
203			return PTR_ERR(data->regmap_pmu);
204	}
205	data->dev = dev;
206
207	desc = devm_kzalloc(dev, sizeof(*desc), GFP_KERNEL);
208	if (!desc)
209		return -ENOMEM;
210
211	desc->ops = &rockchip_dfi_ops;
212	desc->driver_data = data;
213	desc->name = np->name;
214	data->desc = desc;
215
216	data->edev = devm_devfreq_event_add_edev(&pdev->dev, desc);
217	if (IS_ERR(data->edev)) {
218		dev_err(&pdev->dev,
219			"failed to add devfreq-event device\n");
220		return PTR_ERR(data->edev);
221	}
222
223	platform_set_drvdata(pdev, data);
224
225	return 0;
226}
227
228static struct platform_driver rockchip_dfi_driver = {
229	.probe	= rockchip_dfi_probe,
230	.driver = {
231		.name	= "rockchip-dfi",
232		.of_match_table = rockchip_dfi_id_match,
233	},
234};
235module_platform_driver(rockchip_dfi_driver);
236
237MODULE_LICENSE("GPL v2");
238MODULE_AUTHOR("Lin Huang <hl@rock-chips.com>");
239MODULE_DESCRIPTION("Rockchip DFI driver");