xref: /openbmc/linux/drivers/cpufreq/sti-cpufreq.c (revision a70eb93a)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Match running platform with pre-defined OPP values for CPUFreq
4  *
5  * Author: Ajit Pal Singh <ajitpal.singh@st.com>
6  *         Lee Jones <lee.jones@linaro.org>
7  *
8  * Copyright (C) 2015 STMicroelectronics (R&D) Limited
9  */
10 
11 #include <linux/cpu.h>
12 #include <linux/io.h>
13 #include <linux/mfd/syscon.h>
14 #include <linux/module.h>
15 #include <linux/of.h>
16 #include <linux/platform_device.h>
17 #include <linux/pm_opp.h>
18 #include <linux/regmap.h>
19 
20 #define VERSION_ELEMENTS	3
21 #define MAX_PCODE_NAME_LEN	7
22 
23 #define VERSION_SHIFT		28
24 #define HW_INFO_INDEX		1
25 #define MAJOR_ID_INDEX		1
26 #define MINOR_ID_INDEX		2
27 
28 /*
29  * Only match on "suitable for ALL versions" entries
30  *
31  * This will be used with the BIT() macro.  It sets the
32  * top bit of a 32bit value and is equal to 0x80000000.
33  */
34 #define DEFAULT_VERSION		31
35 
36 enum {
37 	PCODE = 0,
38 	SUBSTRATE,
39 	DVFS_MAX_REGFIELDS,
40 };
41 
42 /**
43  * struct sti_cpufreq_ddata - ST CPUFreq Driver Data
44  *
45  * @cpu:		CPU's OF node
46  * @syscfg_eng:		Engineering Syscon register map
47  * @syscfg:		Syscon register map
48  */
49 static struct sti_cpufreq_ddata {
50 	struct device *cpu;
51 	struct regmap *syscfg_eng;
52 	struct regmap *syscfg;
53 } ddata;
54 
sti_cpufreq_fetch_major(void)55 static int sti_cpufreq_fetch_major(void) {
56 	struct device_node *np = ddata.cpu->of_node;
57 	struct device *dev = ddata.cpu;
58 	unsigned int major_offset;
59 	unsigned int socid;
60 	int ret;
61 
62 	ret = of_property_read_u32_index(np, "st,syscfg",
63 					 MAJOR_ID_INDEX, &major_offset);
64 	if (ret) {
65 		dev_err(dev, "No major number offset provided in %pOF [%d]\n",
66 			np, ret);
67 		return ret;
68 	}
69 
70 	ret = regmap_read(ddata.syscfg, major_offset, &socid);
71 	if (ret) {
72 		dev_err(dev, "Failed to read major number from syscon [%d]\n",
73 			ret);
74 		return ret;
75 	}
76 
77 	return ((socid >> VERSION_SHIFT) & 0xf) + 1;
78 }
79 
sti_cpufreq_fetch_minor(void)80 static int sti_cpufreq_fetch_minor(void)
81 {
82 	struct device *dev = ddata.cpu;
83 	struct device_node *np = dev->of_node;
84 	unsigned int minor_offset;
85 	unsigned int minid;
86 	int ret;
87 
88 	ret = of_property_read_u32_index(np, "st,syscfg-eng",
89 					 MINOR_ID_INDEX, &minor_offset);
90 	if (ret) {
91 		dev_err(dev,
92 			"No minor number offset provided %pOF [%d]\n",
93 			np, ret);
94 		return ret;
95 	}
96 
97 	ret = regmap_read(ddata.syscfg_eng, minor_offset, &minid);
98 	if (ret) {
99 		dev_err(dev,
100 			"Failed to read the minor number from syscon [%d]\n",
101 			ret);
102 		return ret;
103 	}
104 
105 	return minid & 0xf;
106 }
107 
sti_cpufreq_fetch_regmap_field(const struct reg_field * reg_fields,int hw_info_offset,int field)108 static int sti_cpufreq_fetch_regmap_field(const struct reg_field *reg_fields,
109 					  int hw_info_offset, int field)
110 {
111 	struct regmap_field *regmap_field;
112 	struct reg_field reg_field = reg_fields[field];
113 	struct device *dev = ddata.cpu;
114 	unsigned int value;
115 	int ret;
116 
117 	reg_field.reg = hw_info_offset;
118 	regmap_field = devm_regmap_field_alloc(dev,
119 					       ddata.syscfg_eng,
120 					       reg_field);
121 	if (IS_ERR(regmap_field)) {
122 		dev_err(dev, "Failed to allocate reg field\n");
123 		return PTR_ERR(regmap_field);
124 	}
125 
126 	ret = regmap_field_read(regmap_field, &value);
127 	if (ret) {
128 		dev_err(dev, "Failed to read %s code\n",
129 			field ? "SUBSTRATE" : "PCODE");
130 		return ret;
131 	}
132 
133 	return value;
134 }
135 
136 static const struct reg_field sti_stih407_dvfs_regfields[DVFS_MAX_REGFIELDS] = {
137 	[PCODE]		= REG_FIELD(0, 16, 19),
138 	[SUBSTRATE]	= REG_FIELD(0, 0, 2),
139 };
140 
sti_cpufreq_match(void)141 static const struct reg_field *sti_cpufreq_match(void)
142 {
143 	if (of_machine_is_compatible("st,stih407") ||
144 	    of_machine_is_compatible("st,stih410") ||
145 	    of_machine_is_compatible("st,stih418"))
146 		return sti_stih407_dvfs_regfields;
147 
148 	return NULL;
149 }
150 
sti_cpufreq_set_opp_info(void)151 static int sti_cpufreq_set_opp_info(void)
152 {
153 	struct device *dev = ddata.cpu;
154 	struct device_node *np = dev->of_node;
155 	const struct reg_field *reg_fields;
156 	unsigned int hw_info_offset;
157 	unsigned int version[VERSION_ELEMENTS];
158 	int pcode, substrate, major, minor;
159 	int opp_token, ret;
160 	char name[MAX_PCODE_NAME_LEN];
161 	struct dev_pm_opp_config config = {
162 		.supported_hw = version,
163 		.supported_hw_count = ARRAY_SIZE(version),
164 		.prop_name = name,
165 	};
166 
167 	reg_fields = sti_cpufreq_match();
168 	if (!reg_fields) {
169 		dev_err(dev, "This SoC doesn't support voltage scaling\n");
170 		return -ENODEV;
171 	}
172 
173 	ret = of_property_read_u32_index(np, "st,syscfg-eng",
174 					 HW_INFO_INDEX, &hw_info_offset);
175 	if (ret) {
176 		dev_warn(dev, "Failed to read HW info offset from DT\n");
177 		substrate = DEFAULT_VERSION;
178 		pcode = 0;
179 		goto use_defaults;
180 	}
181 
182 	pcode = sti_cpufreq_fetch_regmap_field(reg_fields,
183 					       hw_info_offset,
184 					       PCODE);
185 	if (pcode < 0) {
186 		dev_warn(dev, "Failed to obtain process code\n");
187 		/* Use default pcode */
188 		pcode = 0;
189 	}
190 
191 	substrate = sti_cpufreq_fetch_regmap_field(reg_fields,
192 						   hw_info_offset,
193 						   SUBSTRATE);
194 	if (substrate) {
195 		dev_warn(dev, "Failed to obtain substrate code\n");
196 		/* Use default substrate */
197 		substrate = DEFAULT_VERSION;
198 	}
199 
200 use_defaults:
201 	major = sti_cpufreq_fetch_major();
202 	if (major < 0) {
203 		dev_err(dev, "Failed to obtain major version\n");
204 		/* Use default major number */
205 		major = DEFAULT_VERSION;
206 	}
207 
208 	minor = sti_cpufreq_fetch_minor();
209 	if (minor < 0) {
210 		dev_err(dev, "Failed to obtain minor version\n");
211 		/* Use default minor number */
212 		minor = DEFAULT_VERSION;
213 	}
214 
215 	snprintf(name, MAX_PCODE_NAME_LEN, "pcode%d", pcode);
216 
217 	version[0] = BIT(major);
218 	version[1] = BIT(minor);
219 	version[2] = BIT(substrate);
220 
221 	opp_token = dev_pm_opp_set_config(dev, &config);
222 	if (opp_token < 0) {
223 		dev_err(dev, "Failed to set OPP config\n");
224 		return opp_token;
225 	}
226 
227 	dev_dbg(dev, "pcode: %d major: %d minor: %d substrate: %d\n",
228 		pcode, major, minor, substrate);
229 	dev_dbg(dev, "version[0]: %x version[1]: %x version[2]: %x\n",
230 		version[0], version[1], version[2]);
231 
232 	return 0;
233 }
234 
sti_cpufreq_fetch_syscon_registers(void)235 static int sti_cpufreq_fetch_syscon_registers(void)
236 {
237 	struct device *dev = ddata.cpu;
238 	struct device_node *np = dev->of_node;
239 
240 	ddata.syscfg = syscon_regmap_lookup_by_phandle(np, "st,syscfg");
241 	if (IS_ERR(ddata.syscfg)) {
242 		dev_err(dev,  "\"st,syscfg\" not supplied\n");
243 		return PTR_ERR(ddata.syscfg);
244 	}
245 
246 	ddata.syscfg_eng = syscon_regmap_lookup_by_phandle(np, "st,syscfg-eng");
247 	if (IS_ERR(ddata.syscfg_eng)) {
248 		dev_err(dev, "\"st,syscfg-eng\" not supplied\n");
249 		return PTR_ERR(ddata.syscfg_eng);
250 	}
251 
252 	return 0;
253 }
254 
sti_cpufreq_init(void)255 static int __init sti_cpufreq_init(void)
256 {
257 	int ret;
258 
259 	if ((!of_machine_is_compatible("st,stih407")) &&
260 		(!of_machine_is_compatible("st,stih410")) &&
261 		(!of_machine_is_compatible("st,stih418")))
262 		return -ENODEV;
263 
264 	ddata.cpu = get_cpu_device(0);
265 	if (!ddata.cpu) {
266 		dev_err(ddata.cpu, "Failed to get device for CPU0\n");
267 		goto skip_voltage_scaling;
268 	}
269 
270 	if (!of_get_property(ddata.cpu->of_node, "operating-points-v2", NULL)) {
271 		dev_err(ddata.cpu, "OPP-v2 not supported\n");
272 		goto skip_voltage_scaling;
273 	}
274 
275 	ret = sti_cpufreq_fetch_syscon_registers();
276 	if (ret)
277 		goto skip_voltage_scaling;
278 
279 	ret = sti_cpufreq_set_opp_info();
280 	if (!ret)
281 		goto register_cpufreq_dt;
282 
283 skip_voltage_scaling:
284 	dev_err(ddata.cpu, "Not doing voltage scaling\n");
285 
286 register_cpufreq_dt:
287 	platform_device_register_simple("cpufreq-dt", -1, NULL, 0);
288 
289 	return 0;
290 }
291 module_init(sti_cpufreq_init);
292 
293 static const struct of_device_id __maybe_unused sti_cpufreq_of_match[] = {
294 	{ .compatible = "st,stih407" },
295 	{ .compatible = "st,stih410" },
296 	{ },
297 };
298 MODULE_DEVICE_TABLE(of, sti_cpufreq_of_match);
299 
300 MODULE_DESCRIPTION("STMicroelectronics CPUFreq/OPP driver");
301 MODULE_AUTHOR("Ajitpal Singh <ajitpal.singh@st.com>");
302 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
303 MODULE_LICENSE("GPL v2");
304