drivers/cpufreq/sti-cpufreq.c

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