arch/arm/mach-omap2/voltage.c

   1 /*
   2  * OMAP3/OMAP4 Voltage Management Routines
   3  *
   4  * Author: Thara Gopinath       <thara@ti.com>
   5  *
   6  * Copyright (C) 2007 Texas Instruments, Inc.
   7  * Rajendra Nayak <rnayak@ti.com>
   8  * Lesly A M <x0080970@ti.com>
   9  *
  10  * Copyright (C) 2008, 2011 Nokia Corporation
  11  * Kalle Jokiniemi
  12  * Paul Walmsley
  13  *
  14  * Copyright (C) 2010 Texas Instruments, Inc.
  15  * Thara Gopinath <thara@ti.com>
  16  *
  17  * This program is free software; you can redistribute it and/or modify
  18  * it under the terms of the GNU General Public License version 2 as
  19  * published by the Free Software Foundation.
  20  */
  21
  22 #include <linux/delay.h>
  23 #include <linux/io.h>
  24 #include <linux/err.h>
  25 #include <linux/export.h>
  26 #include <linux/debugfs.h>
  27 #include <linux/slab.h>
  28 #include <linux/clk.h>
  29
  30 #include <plat/common.h>
  31
  32 #include "prm-regbits-34xx.h"
  33 #include "prm-regbits-44xx.h"
  34 #include "prm44xx.h"
  35 #include "prcm44xx.h"
  36 #include "prminst44xx.h"
  37 #include "control.h"
  38
  39 #include "voltage.h"
  40 #include "powerdomain.h"
  41
  42 #include "vc.h"
  43 #include "vp.h"
  44
  45 static LIST_HEAD(voltdm_list);
  46
  47 /* Public functions */
  48 /**
  49  * voltdm_get_voltage() - Gets the current non-auto-compensated voltage
  50  * @voltdm:     pointer to the voltdm for which current voltage info is needed
  51  *
  52  * API to get the current non-auto-compensated voltage for a voltage domain.
  53  * Returns 0 in case of error else returns the current voltage.
  54  */
  55 unsigned long voltdm_get_voltage(struct voltagedomain *voltdm)
  56 {
  57         if (!voltdm || IS_ERR(voltdm)) {
  58                 pr_warning("%s: VDD specified does not exist!\n", __func__);
  59                 return 0;
  60         }
  61
  62         return voltdm->nominal_volt;
  63 }
  64
  65 /**
  66  * voltdm_scale() - API to scale voltage of a particular voltage domain.
  67  * @voltdm: pointer to the voltage domain which is to be scaled.
  68  * @target_volt: The target voltage of the voltage domain
  69  *
  70  * This API should be called by the kernel to do the voltage scaling
  71  * for a particular voltage domain during DVFS.
  72  */
  73 int voltdm_scale(struct voltagedomain *voltdm,
  74                  unsigned long target_volt)
  75 {
  76         int ret;
  77
  78         if (!voltdm || IS_ERR(voltdm)) {
  79                 pr_warning("%s: VDD specified does not exist!\n", __func__);
  80                 return -EINVAL;
  81         }
  82
  83         if (!voltdm->scale) {
  84                 pr_err("%s: No voltage scale API registered for vdd_%s\n",
  85                         __func__, voltdm->name);
  86                 return -ENODATA;
  87         }
  88
  89         ret = voltdm->scale(voltdm, target_volt);
  90         if (!ret)
  91                 voltdm->nominal_volt = target_volt;
  92
  93         return ret;
  94 }
  95
  96 /**
  97  * voltdm_reset() - Resets the voltage of a particular voltage domain
  98  *                  to that of the current OPP.
  99  * @voltdm: pointer to the voltage domain whose voltage is to be reset.
 100  *
 101  * This API finds out the correct voltage the voltage domain is supposed
 102  * to be at and resets the voltage to that level. Should be used especially
 103  * while disabling any voltage compensation modules.
 104  */
 105 void voltdm_reset(struct voltagedomain *voltdm)
 106 {
 107         unsigned long target_volt;
 108
 109         if (!voltdm || IS_ERR(voltdm)) {
 110                 pr_warning("%s: VDD specified does not exist!\n", __func__);
 111                 return;
 112         }
 113
 114         target_volt = voltdm_get_voltage(voltdm);
 115         if (!target_volt) {
 116                 pr_err("%s: unable to find current voltage for vdd_%s\n",
 117                         __func__, voltdm->name);
 118                 return;
 119         }
 120
 121         voltdm_scale(voltdm, target_volt);
 122 }
 123
 124 /**
 125  * omap_voltage_get_volttable() - API to get the voltage table associated with a
 126  *                              particular voltage domain.
 127  * @voltdm:     pointer to the VDD for which the voltage table is required
 128  * @volt_data:  the voltage table for the particular vdd which is to be
 129  *              populated by this API
 130  *
 131  * This API populates the voltage table associated with a VDD into the
 132  * passed parameter pointer. Returns the count of distinct voltages
 133  * supported by this vdd.
 134  *
 135  */
 136 void omap_voltage_get_volttable(struct voltagedomain *voltdm,
 137                                 struct omap_volt_data **volt_data)
 138 {
 139         if (!voltdm || IS_ERR(voltdm)) {
 140                 pr_warning("%s: VDD specified does not exist!\n", __func__);
 141                 return;
 142         }
 143
 144         *volt_data = voltdm->volt_data;
 145 }
 146
 147 /**
 148  * omap_voltage_get_voltdata() - API to get the voltage table entry for a
 149  *                              particular voltage
 150  * @voltdm:     pointer to the VDD whose voltage table has to be searched
 151  * @volt:       the voltage to be searched in the voltage table
 152  *
 153  * This API searches through the voltage table for the required voltage
 154  * domain and tries to find a matching entry for the passed voltage volt.
 155  * If a matching entry is found volt_data is populated with that entry.
 156  * This API searches only through the non-compensated voltages int the
 157  * voltage table.
 158  * Returns pointer to the voltage table entry corresponding to volt on
 159  * success. Returns -ENODATA if no voltage table exisits for the passed voltage
 160  * domain or if there is no matching entry.
 161  */
 162 struct omap_volt_data *omap_voltage_get_voltdata(struct voltagedomain *voltdm,
 163                                                  unsigned long volt)
 164 {
 165         int i;
 166
 167         if (!voltdm || IS_ERR(voltdm)) {
 168                 pr_warning("%s: VDD specified does not exist!\n", __func__);
 169                 return ERR_PTR(-EINVAL);
 170         }
 171
 172         if (!voltdm->volt_data) {
 173                 pr_warning("%s: voltage table does not exist for vdd_%s\n",
 174                         __func__, voltdm->name);
 175                 return ERR_PTR(-ENODATA);
 176         }
 177
 178         for (i = 0; voltdm->volt_data[i].volt_nominal != 0; i++) {
 179                 if (voltdm->volt_data[i].volt_nominal == volt)
 180                         return &voltdm->volt_data[i];
 181         }
 182
 183         pr_notice("%s: Unable to match the current voltage with the voltage"
 184                 "table for vdd_%s\n", __func__, voltdm->name);
 185
 186         return ERR_PTR(-ENODATA);
 187 }
 188
 189 /**
 190  * omap_voltage_register_pmic() - API to register PMIC specific data
 191  * @voltdm:     pointer to the VDD for which the PMIC specific data is
 192  *              to be registered
 193  * @pmic:       the structure containing pmic info
 194  *
 195  * This API is to be called by the SOC/PMIC file to specify the
 196  * pmic specific info as present in omap_voltdm_pmic structure.
 197  */
 198 int omap_voltage_register_pmic(struct voltagedomain *voltdm,
 199                                struct omap_voltdm_pmic *pmic)
 200 {
 201         if (!voltdm || IS_ERR(voltdm)) {
 202                 pr_warning("%s: VDD specified does not exist!\n", __func__);
 203                 return -EINVAL;
 204         }
 205
 206         voltdm->pmic = pmic;
 207
 208         return 0;
 209 }
 210
 211 /**
 212  * omap_change_voltscale_method() - API to change the voltage scaling method.
 213  * @voltdm:     pointer to the VDD whose voltage scaling method
 214  *              has to be changed.
 215  * @voltscale_method:   the method to be used for voltage scaling.
 216  *
 217  * This API can be used by the board files to change the method of voltage
 218  * scaling between vpforceupdate and vcbypass. The parameter values are
 219  * defined in voltage.h
 220  */
 221 void omap_change_voltscale_method(struct voltagedomain *voltdm,
 222                                   int voltscale_method)
 223 {
 224         if (!voltdm || IS_ERR(voltdm)) {
 225                 pr_warning("%s: VDD specified does not exist!\n", __func__);
 226                 return;
 227         }
 228
 229         switch (voltscale_method) {
 230         case VOLTSCALE_VPFORCEUPDATE:
 231                 voltdm->scale = omap_vp_forceupdate_scale;
 232                 return;
 233         case VOLTSCALE_VCBYPASS:
 234                 voltdm->scale = omap_vc_bypass_scale;
 235                 return;
 236         default:
 237                 pr_warning("%s: Trying to change the method of voltage scaling"
 238                         "to an unsupported one!\n", __func__);
 239         }
 240 }
 241
 242 /**
 243  * omap_voltage_late_init() - Init the various voltage parameters
 244  *
 245  * This API is to be called in the later stages of the
 246  * system boot to init the voltage controller and
 247  * voltage processors.
 248  */
 249 int __init omap_voltage_late_init(void)
 250 {
 251         struct voltagedomain *voltdm;
 252
 253         if (list_empty(&voltdm_list)) {
 254                 pr_err("%s: Voltage driver support not added\n",
 255                         __func__);
 256                 return -EINVAL;
 257         }
 258
 259         list_for_each_entry(voltdm, &voltdm_list, node) {
 260                 struct clk *sys_ck;
 261
 262                 if (!voltdm->scalable)
 263                         continue;
 264
 265                 sys_ck = clk_get(NULL, voltdm->sys_clk.name);
 266                 if (IS_ERR(sys_ck)) {
 267                         pr_warning("%s: Could not get sys clk.\n", __func__);
 268                         return -EINVAL;
 269                 }
 270                 voltdm->sys_clk.rate = clk_get_rate(sys_ck);
 271                 WARN_ON(!voltdm->sys_clk.rate);
 272                 clk_put(sys_ck);
 273
 274                 if (voltdm->vc) {
 275                         voltdm->scale = omap_vc_bypass_scale;
 276                         omap_vc_init_channel(voltdm);
 277                 }
 278
 279                 if (voltdm->vp) {
 280                         voltdm->scale = omap_vp_forceupdate_scale;
 281                         omap_vp_init(voltdm);
 282                 }
 283         }
 284
 285         return 0;
 286 }
 287
 288 static struct voltagedomain *_voltdm_lookup(const char *name)
 289 {
 290         struct voltagedomain *voltdm, *temp_voltdm;
 291
 292         voltdm = NULL;
 293
 294         list_for_each_entry(temp_voltdm, &voltdm_list, node) {
 295                 if (!strcmp(name, temp_voltdm->name)) {
 296                         voltdm = temp_voltdm;
 297                         break;
 298                 }
 299         }
 300
 301         return voltdm;
 302 }
 303
 304 /**
 305  * voltdm_add_pwrdm - add a powerdomain to a voltagedomain
 306  * @voltdm: struct voltagedomain * to add the powerdomain to
 307  * @pwrdm: struct powerdomain * to associate with a voltagedomain
 308  *
 309  * Associate the powerdomain @pwrdm with a voltagedomain @voltdm.  This
 310  * enables the use of voltdm_for_each_pwrdm().  Returns -EINVAL if
 311  * presented with invalid pointers; -ENOMEM if memory could not be allocated;
 312  * or 0 upon success.
 313  */
 314 int voltdm_add_pwrdm(struct voltagedomain *voltdm, struct powerdomain *pwrdm)
 315 {
 316         if (!voltdm || !pwrdm)
 317                 return -EINVAL;
 318
 319         pr_debug("voltagedomain: associating powerdomain %s with voltagedomain "
 320                  "%s\n", pwrdm->name, voltdm->name);
 321
 322         list_add(&pwrdm->voltdm_node, &voltdm->pwrdm_list);
 323
 324         return 0;
 325 }
 326
 327 /**
 328  * voltdm_for_each_pwrdm - call function for each pwrdm in a voltdm
 329  * @voltdm: struct voltagedomain * to iterate over
 330  * @fn: callback function *
 331  *
 332  * Call the supplied function @fn for each powerdomain in the
 333  * voltagedomain @voltdm.  Returns -EINVAL if presented with invalid
 334  * pointers; or passes along the last return value of the callback
 335  * function, which should be 0 for success or anything else to
 336  * indicate failure.
 337  */
 338 int voltdm_for_each_pwrdm(struct voltagedomain *voltdm,
 339                           int (*fn)(struct voltagedomain *voltdm,
 340                                     struct powerdomain *pwrdm))
 341 {
 342         struct powerdomain *pwrdm;
 343         int ret = 0;
 344
 345         if (!fn)
 346                 return -EINVAL;
 347
 348         list_for_each_entry(pwrdm, &voltdm->pwrdm_list, voltdm_node)
 349                 ret = (*fn)(voltdm, pwrdm);
 350
 351         return ret;
 352 }
 353
 354 /**
 355  * voltdm_for_each - call function on each registered voltagedomain
 356  * @fn: callback function *
 357  *
 358  * Call the supplied function @fn for each registered voltagedomain.
 359  * The callback function @fn can return anything but 0 to bail out
 360  * early from the iterator.  Returns the last return value of the
 361  * callback function, which should be 0 for success or anything else
 362  * to indicate failure; or -EINVAL if the function pointer is null.
 363  */
 364 int voltdm_for_each(int (*fn)(struct voltagedomain *voltdm, void *user),
 365                     void *user)
 366 {
 367         struct voltagedomain *temp_voltdm;
 368         int ret = 0;
 369
 370         if (!fn)
 371                 return -EINVAL;
 372
 373         list_for_each_entry(temp_voltdm, &voltdm_list, node) {
 374                 ret = (*fn)(temp_voltdm, user);
 375                 if (ret)
 376                         break;
 377         }
 378
 379         return ret;
 380 }
 381
 382 static int _voltdm_register(struct voltagedomain *voltdm)
 383 {
 384         if (!voltdm || !voltdm->name)
 385                 return -EINVAL;
 386
 387         INIT_LIST_HEAD(&voltdm->pwrdm_list);
 388         list_add(&voltdm->node, &voltdm_list);
 389
 390         pr_debug("voltagedomain: registered %s\n", voltdm->name);
 391
 392         return 0;
 393 }
 394
 395 /**
 396  * voltdm_lookup - look up a voltagedomain by name, return a pointer
 397  * @name: name of voltagedomain
 398  *
 399  * Find a registered voltagedomain by its name @name.  Returns a pointer
 400  * to the struct voltagedomain if found, or NULL otherwise.
 401  */
 402 struct voltagedomain *voltdm_lookup(const char *name)
 403 {
 404         struct voltagedomain *voltdm ;
 405
 406         if (!name)
 407                 return NULL;
 408
 409         voltdm = _voltdm_lookup(name);
 410
 411         return voltdm;
 412 }
 413
 414 /**
 415  * voltdm_init - set up the voltagedomain layer
 416  * @voltdm_list: array of struct voltagedomain pointers to register
 417  *
 418  * Loop through the array of voltagedomains @voltdm_list, registering all
 419  * that are available on the current CPU. If voltdm_list is supplied
 420  * and not null, all of the referenced voltagedomains will be
 421  * registered.  No return value.
 422  */
 423 void voltdm_init(struct voltagedomain **voltdms)
 424 {
 425         struct voltagedomain **v;
 426
 427         if (voltdms) {
 428                 for (v = voltdms; *v; v++)
 429                         _voltdm_register(*v);
 430         }
 431 }