aboutsummaryrefslogtreecommitdiff
path: root/drivers/cpufreq/sti-cpufreq.c
blob: 47105735df12651dcad502aff80f069ca9f447be (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
/*
 * Match running platform with pre-defined OPP values for CPUFreq
 *
 * Author: Ajit Pal Singh <ajitpal.singh@st.com>
 *         Lee Jones <lee.jones@linaro.org>
 *
 * Copyright (C) 2015 STMicroelectronics (R&D) Limited
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the version 2 of the GNU General Public License as
 * published by the Free Software Foundation
 */

#include <linux/cpu.h>
#include <linux/io.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/pm_opp.h>
#include <linux/regmap.h>

#define VERSION_ELEMENTS	3
#define MAX_PCODE_NAME_LEN	7

#define VERSION_SHIFT		28
#define HW_INFO_INDEX		1
#define MAJOR_ID_INDEX		1
#define MINOR_ID_INDEX		2

/*
 * Only match on "suitable for ALL versions" entries
 *
 * This will be used with the BIT() macro.  It sets the
 * top bit of a 32bit value and is equal to 0x80000000.
 */
#define DEFAULT_VERSION		31

enum {
	PCODE = 0,
	SUBSTRATE,
	DVFS_MAX_REGFIELDS,
};

/**
 * ST CPUFreq Driver Data
 *
 * @cpu_node		CPU's OF node
 * @syscfg_eng		Engineering Syscon register map
 * @regmap		Syscon register map
 */
static struct sti_cpufreq_ddata {
	struct device *cpu;
	struct regmap *syscfg_eng;
	struct regmap *syscfg;
} ddata;

static int sti_cpufreq_fetch_major(void) {
	struct device_node *np = ddata.cpu->of_node;
	struct device *dev = ddata.cpu;
	unsigned int major_offset;
	unsigned int socid;
	int ret;

	ret = of_property_read_u32_index(np, "st,syscfg",
					 MAJOR_ID_INDEX, &major_offset);
	if (ret) {
		dev_err(dev, "No major number offset provided in %pOF [%d]\n",
			np, ret);
		return ret;
	}

	ret = regmap_read(ddata.syscfg, major_offset, &socid);
	if (ret) {
		dev_err(dev, "Failed to read major number from syscon [%d]\n",
			ret);
		return ret;
	}

	return ((socid >> VERSION_SHIFT) & 0xf) + 1;
}

static int sti_cpufreq_fetch_minor(void)
{
	struct device *dev = ddata.cpu;
	struct device_node *np = dev->of_node;
	unsigned int minor_offset;
	unsigned int minid;
	int ret;

	ret = of_property_read_u32_index(np, "st,syscfg-eng",
					 MINOR_ID_INDEX, &minor_offset);
	if (ret) {
		dev_err(dev,
			"No minor number offset provided %pOF [%d]\n",
			np, ret);
		return ret;
	}

	ret = regmap_read(ddata.syscfg_eng, minor_offset, &minid);
	if (ret) {
		dev_err(dev,
			"Failed to read the minor number from syscon [%d]\n",
			ret);
		return ret;
	}

	return minid & 0xf;
}

static int sti_cpufreq_fetch_regmap_field(const struct reg_field *reg_fields,
					  int hw_info_offset, int field)
{
	struct regmap_field *regmap_field;
	struct reg_field reg_field = reg_fields[field];
	struct device *dev = ddata.cpu;
	unsigned int value;
	int ret;

	reg_field.reg = hw_info_offset;
	regmap_field = devm_regmap_field_alloc(dev,
					       ddata.syscfg_eng,
					       reg_field);
	if (IS_ERR(regmap_field)) {
		dev_err(dev, "Failed to allocate reg field\n");
		return PTR_ERR(regmap_field);
	}

	ret = regmap_field_read(regmap_field, &value);
	if (ret) {
		dev_err(dev, "Failed to read %s code\n",
			field ? "SUBSTRATE" : "PCODE");
		return ret;
	}

	return value;
}

static const struct reg_field sti_stih407_dvfs_regfields[DVFS_MAX_REGFIELDS] = {
	[PCODE]		= REG_FIELD(0, 16, 19),
	[SUBSTRATE]	= REG_FIELD(0, 0, 2),
};

static const struct reg_field *sti_cpufreq_match(void)
{
	if (of_machine_is_compatible("st,stih407") ||
	    of_machine_is_compatible("st,stih410"))
		return sti_stih407_dvfs_regfields;

	return NULL;
}

static int sti_cpufreq_set_opp_info(void)
{
	struct device *dev = ddata.cpu;
	struct device_node *np = dev->of_node;
	const struct reg_field *reg_fields;
	unsigned int hw_info_offset;
	unsigned int version[VERSION_ELEMENTS];
	int pcode, substrate, major, minor;
	int ret;
	char name[MAX_PCODE_NAME_LEN];
	struct opp_table *opp_table;

	reg_fields = sti_cpufreq_match();
	if (!reg_fields) {
		dev_err(dev, "This SoC doesn't support voltage scaling\n");
		return -ENODEV;
	}

	ret = of_property_read_u32_index(np, "st,syscfg-eng",
					 HW_INFO_INDEX, &hw_info_offset);
	if (ret) {
		dev_warn(dev, "Failed to read HW info offset from DT\n");
		substrate = DEFAULT_VERSION;
		pcode = 0;
		goto use_defaults;
	}

	pcode = sti_cpufreq_fetch_regmap_field(reg_fields,
					       hw_info_offset,
					       PCODE);
	if (pcode < 0) {
		dev_warn(dev, "Failed to obtain process code\n");
		/* Use default pcode */
		pcode = 0;
	}

	substrate = sti_cpufreq_fetch_regmap_field(reg_fields,
						   hw_info_offset,
						   SUBSTRATE);
	if (substrate) {
		dev_warn(dev, "Failed to obtain substrate code\n");
		/* Use default substrate */
		substrate = DEFAULT_VERSION;
	}

use_defaults:
	major = sti_cpufreq_fetch_major();
	if (major < 0) {
		dev_err(dev, "Failed to obtain major version\n");
		/* Use default major number */
		major = DEFAULT_VERSION;
	}

	minor = sti_cpufreq_fetch_minor();
	if (minor < 0) {
		dev_err(dev, "Failed to obtain minor version\n");
		/* Use default minor number */
		minor = DEFAULT_VERSION;
	}

	snprintf(name, MAX_PCODE_NAME_LEN, "pcode%d", pcode);

	opp_table = dev_pm_opp_set_prop_name(dev, name);
	if (IS_ERR(opp_table)) {
		dev_err(dev, "Failed to set prop name\n");
		return PTR_ERR(opp_table);
	}

	version[0] = BIT(major);
	version[1] = BIT(minor);
	version[2] = BIT(substrate);

	opp_table = dev_pm_opp_set_supported_hw(dev, version, VERSION_ELEMENTS);
	if (IS_ERR(opp_table)) {
		dev_err(dev, "Failed to set supported hardware\n");
		return PTR_ERR(opp_table);
	}

	dev_dbg(dev, "pcode: %d major: %d minor: %d substrate: %d\n",
		pcode, major, minor, substrate);
	dev_dbg(dev, "version[0]: %x version[1]: %x version[2]: %x\n",
		version[0], version[1], version[2]);

	return 0;
}

static int sti_cpufreq_fetch_syscon_registers(void)
{
	struct device *dev = ddata.cpu;
	struct device_node *np = dev->of_node;

	ddata.syscfg = syscon_regmap_lookup_by_phandle(np, "st,syscfg");
	if (IS_ERR(ddata.syscfg)) {
		dev_err(dev,  "\"st,syscfg\" not supplied\n");
		return PTR_ERR(ddata.syscfg);
	}

	ddata.syscfg_eng = syscon_regmap_lookup_by_phandle(np, "st,syscfg-eng");
	if (IS_ERR(ddata.syscfg_eng)) {
		dev_err(dev, "\"st,syscfg-eng\" not supplied\n");
		return PTR_ERR(ddata.syscfg_eng);
	}

	return 0;
}

static int sti_cpufreq_init(void)
{
	int ret;

	if ((!of_machine_is_compatible("st,stih407")) &&
		(!of_machine_is_compatible("st,stih410")))
		return -ENODEV;

	ddata.cpu = get_cpu_device(0);
	if (!ddata.cpu) {
		dev_err(ddata.cpu, "Failed to get device for CPU0\n");
		goto skip_voltage_scaling;
	}

	if (!of_get_property(ddata.cpu->of_node, "operating-points-v2", NULL)) {
		dev_err(ddata.cpu, "OPP-v2 not supported\n");
		goto skip_voltage_scaling;
	}

	ret = sti_cpufreq_fetch_syscon_registers();
	if (ret)
		goto skip_voltage_scaling;

	ret = sti_cpufreq_set_opp_info();
	if (!ret)
		goto register_cpufreq_dt;

skip_voltage_scaling:
	dev_err(ddata.cpu, "Not doing voltage scaling\n");

register_cpufreq_dt:
	platform_device_register_simple("cpufreq-dt", -1, NULL, 0);

	return 0;
}
module_init(sti_cpufreq_init);

MODULE_DESCRIPTION("STMicroelectronics CPUFreq/OPP driver");
MODULE_AUTHOR("Ajitpal Singh <ajitpal.singh@st.com>");
MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
MODULE_LICENSE("GPL v2");