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/of_platform.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 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 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 } 107 108 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 }; 140 141 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 } 150 151 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 ret; 160 char name[MAX_PCODE_NAME_LEN]; 161 struct opp_table *opp_table; 162 163 reg_fields = sti_cpufreq_match(); 164 if (!reg_fields) { 165 dev_err(dev, "This SoC doesn't support voltage scaling\n"); 166 return -ENODEV; 167 } 168 169 ret = of_property_read_u32_index(np, "st,syscfg-eng", 170 HW_INFO_INDEX, &hw_info_offset); 171 if (ret) { 172 dev_warn(dev, "Failed to read HW info offset from DT\n"); 173 substrate = DEFAULT_VERSION; 174 pcode = 0; 175 goto use_defaults; 176 } 177 178 pcode = sti_cpufreq_fetch_regmap_field(reg_fields, 179 hw_info_offset, 180 PCODE); 181 if (pcode < 0) { 182 dev_warn(dev, "Failed to obtain process code\n"); 183 /* Use default pcode */ 184 pcode = 0; 185 } 186 187 substrate = sti_cpufreq_fetch_regmap_field(reg_fields, 188 hw_info_offset, 189 SUBSTRATE); 190 if (substrate) { 191 dev_warn(dev, "Failed to obtain substrate code\n"); 192 /* Use default substrate */ 193 substrate = DEFAULT_VERSION; 194 } 195 196 use_defaults: 197 major = sti_cpufreq_fetch_major(); 198 if (major < 0) { 199 dev_err(dev, "Failed to obtain major version\n"); 200 /* Use default major number */ 201 major = DEFAULT_VERSION; 202 } 203 204 minor = sti_cpufreq_fetch_minor(); 205 if (minor < 0) { 206 dev_err(dev, "Failed to obtain minor version\n"); 207 /* Use default minor number */ 208 minor = DEFAULT_VERSION; 209 } 210 211 snprintf(name, MAX_PCODE_NAME_LEN, "pcode%d", pcode); 212 213 opp_table = dev_pm_opp_set_prop_name(dev, name); 214 if (IS_ERR(opp_table)) { 215 dev_err(dev, "Failed to set prop name\n"); 216 return PTR_ERR(opp_table); 217 } 218 219 version[0] = BIT(major); 220 version[1] = BIT(minor); 221 version[2] = BIT(substrate); 222 223 opp_table = dev_pm_opp_set_supported_hw(dev, version, VERSION_ELEMENTS); 224 if (IS_ERR(opp_table)) { 225 dev_err(dev, "Failed to set supported hardware\n"); 226 return PTR_ERR(opp_table); 227 } 228 229 dev_dbg(dev, "pcode: %d major: %d minor: %d substrate: %d\n", 230 pcode, major, minor, substrate); 231 dev_dbg(dev, "version[0]: %x version[1]: %x version[2]: %x\n", 232 version[0], version[1], version[2]); 233 234 return 0; 235 } 236 237 static int sti_cpufreq_fetch_syscon_registers(void) 238 { 239 struct device *dev = ddata.cpu; 240 struct device_node *np = dev->of_node; 241 242 ddata.syscfg = syscon_regmap_lookup_by_phandle(np, "st,syscfg"); 243 if (IS_ERR(ddata.syscfg)) { 244 dev_err(dev, "\"st,syscfg\" not supplied\n"); 245 return PTR_ERR(ddata.syscfg); 246 } 247 248 ddata.syscfg_eng = syscon_regmap_lookup_by_phandle(np, "st,syscfg-eng"); 249 if (IS_ERR(ddata.syscfg_eng)) { 250 dev_err(dev, "\"st,syscfg-eng\" not supplied\n"); 251 return PTR_ERR(ddata.syscfg_eng); 252 } 253 254 return 0; 255 } 256 257 static int sti_cpufreq_init(void) 258 { 259 int ret; 260 261 if ((!of_machine_is_compatible("st,stih407")) && 262 (!of_machine_is_compatible("st,stih410")) && 263 (!of_machine_is_compatible("st,stih418"))) 264 return -ENODEV; 265 266 ddata.cpu = get_cpu_device(0); 267 if (!ddata.cpu) { 268 dev_err(ddata.cpu, "Failed to get device for CPU0\n"); 269 goto skip_voltage_scaling; 270 } 271 272 if (!of_get_property(ddata.cpu->of_node, "operating-points-v2", NULL)) { 273 dev_err(ddata.cpu, "OPP-v2 not supported\n"); 274 goto skip_voltage_scaling; 275 } 276 277 ret = sti_cpufreq_fetch_syscon_registers(); 278 if (ret) 279 goto skip_voltage_scaling; 280 281 ret = sti_cpufreq_set_opp_info(); 282 if (!ret) 283 goto register_cpufreq_dt; 284 285 skip_voltage_scaling: 286 dev_err(ddata.cpu, "Not doing voltage scaling\n"); 287 288 register_cpufreq_dt: 289 platform_device_register_simple("cpufreq-dt", -1, NULL, 0); 290 291 return 0; 292 } 293 module_init(sti_cpufreq_init); 294 295 MODULE_DESCRIPTION("STMicroelectronics CPUFreq/OPP driver"); 296 MODULE_AUTHOR("Ajitpal Singh <ajitpal.singh@st.com>"); 297 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>"); 298 MODULE_LICENSE("GPL v2"); 299