drivers/opp/of.c

   1 /*
   2  * Generic OPP OF helpers
   3  *
   4  * Copyright (C) 2009-2010 Texas Instruments Incorporated.
   5  *      Nishanth Menon
   6  *      Romit Dasgupta
   7  *      Kevin Hilman
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  15
  16 #include <linux/cpu.h>
  17 #include <linux/errno.h>
  18 #include <linux/device.h>
  19 #include <linux/of_device.h>
  20 #include <linux/pm_domain.h>
  21 #include <linux/slab.h>
  22 #include <linux/export.h>
  23
  24 #include "opp.h"
  25
  26 static struct opp_table *_managed_opp(const struct device_node *np)
  27 {
  28         struct opp_table *opp_table, *managed_table = NULL;
  29
  30         mutex_lock(&opp_table_lock);
  31
  32         list_for_each_entry(opp_table, &opp_tables, node) {
  33                 if (opp_table->np == np) {
  34                         /*
  35                          * Multiple devices can point to the same OPP table and
  36                          * so will have same node-pointer, np.
  37                          *
  38                          * But the OPPs will be considered as shared only if the
  39                          * OPP table contains a "opp-shared" property.
  40                          */
  41                         if (opp_table->shared_opp == OPP_TABLE_ACCESS_SHARED) {
  42                                 _get_opp_table_kref(opp_table);
  43                                 managed_table = opp_table;
  44                         }
  45
  46                         break;
  47                 }
  48         }
  49
  50         mutex_unlock(&opp_table_lock);
  51
  52         return managed_table;
  53 }
  54
  55 void _of_init_opp_table(struct opp_table *opp_table, struct device *dev)
  56 {
  57         struct device_node *np;
  58
  59         /*
  60          * Only required for backward compatibility with v1 bindings, but isn't
  61          * harmful for other cases. And so we do it unconditionally.
  62          */
  63         np = of_node_get(dev->of_node);
  64         if (np) {
  65                 u32 val;
  66
  67                 if (!of_property_read_u32(np, "clock-latency", &val))
  68                         opp_table->clock_latency_ns_max = val;
  69                 of_property_read_u32(np, "voltage-tolerance",
  70                                      &opp_table->voltage_tolerance_v1);
  71                 of_node_put(np);
  72         }
  73 }
  74
  75 static bool _opp_is_supported(struct device *dev, struct opp_table *opp_table,
  76                               struct device_node *np)
  77 {
  78         unsigned int count = opp_table->supported_hw_count;
  79         u32 version;
  80         int ret;
  81
  82         if (!opp_table->supported_hw) {
  83                 /*
  84                  * In the case that no supported_hw has been set by the
  85                  * platform but there is an opp-supported-hw value set for
  86                  * an OPP then the OPP should not be enabled as there is
  87                  * no way to see if the hardware supports it.
  88                  */
  89                 if (of_find_property(np, "opp-supported-hw", NULL))
  90                         return false;
  91                 else
  92                         return true;
  93         }
  94
  95         while (count--) {
  96                 ret = of_property_read_u32_index(np, "opp-supported-hw", count,
  97                                                  &version);
  98                 if (ret) {
  99                         dev_warn(dev, "%s: failed to read opp-supported-hw property at index %d: %d\n",
 100                                  __func__, count, ret);
 101                         return false;
 102                 }
 103
 104                 /* Both of these are bitwise masks of the versions */
 105                 if (!(version & opp_table->supported_hw[count]))
 106                         return false;
 107         }
 108
 109         return true;
 110 }
 111
 112 static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
 113                               struct opp_table *opp_table)
 114 {
 115         u32 *microvolt, *microamp = NULL;
 116         int supplies, vcount, icount, ret, i, j;
 117         struct property *prop = NULL;
 118         char name[NAME_MAX];
 119
 120         supplies = opp_table->regulator_count ? opp_table->regulator_count : 1;
 121
 122         /* Search for "opp-microvolt-<name>" */
 123         if (opp_table->prop_name) {
 124                 snprintf(name, sizeof(name), "opp-microvolt-%s",
 125                          opp_table->prop_name);
 126                 prop = of_find_property(opp->np, name, NULL);
 127         }
 128
 129         if (!prop) {
 130                 /* Search for "opp-microvolt" */
 131                 sprintf(name, "opp-microvolt");
 132                 prop = of_find_property(opp->np, name, NULL);
 133
 134                 /* Missing property isn't a problem, but an invalid entry is */
 135                 if (!prop) {
 136                         if (!opp_table->regulator_count)
 137                                 return 0;
 138
 139                         dev_err(dev, "%s: opp-microvolt missing although OPP managing regulators\n",
 140                                 __func__);
 141                         return -EINVAL;
 142                 }
 143         }
 144
 145         vcount = of_property_count_u32_elems(opp->np, name);
 146         if (vcount < 0) {
 147                 dev_err(dev, "%s: Invalid %s property (%d)\n",
 148                         __func__, name, vcount);
 149                 return vcount;
 150         }
 151
 152         /* There can be one or three elements per supply */
 153         if (vcount != supplies && vcount != supplies * 3) {
 154                 dev_err(dev, "%s: Invalid number of elements in %s property (%d) with supplies (%d)\n",
 155                         __func__, name, vcount, supplies);
 156                 return -EINVAL;
 157         }
 158
 159         microvolt = kmalloc_array(vcount, sizeof(*microvolt), GFP_KERNEL);
 160         if (!microvolt)
 161                 return -ENOMEM;
 162
 163         ret = of_property_read_u32_array(opp->np, name, microvolt, vcount);
 164         if (ret) {
 165                 dev_err(dev, "%s: error parsing %s: %d\n", __func__, name, ret);
 166                 ret = -EINVAL;
 167                 goto free_microvolt;
 168         }
 169
 170         /* Search for "opp-microamp-<name>" */
 171         prop = NULL;
 172         if (opp_table->prop_name) {
 173                 snprintf(name, sizeof(name), "opp-microamp-%s",
 174                          opp_table->prop_name);
 175                 prop = of_find_property(opp->np, name, NULL);
 176         }
 177
 178         if (!prop) {
 179                 /* Search for "opp-microamp" */
 180                 sprintf(name, "opp-microamp");
 181                 prop = of_find_property(opp->np, name, NULL);
 182         }
 183
 184         if (prop) {
 185                 icount = of_property_count_u32_elems(opp->np, name);
 186                 if (icount < 0) {
 187                         dev_err(dev, "%s: Invalid %s property (%d)\n", __func__,
 188                                 name, icount);
 189                         ret = icount;
 190                         goto free_microvolt;
 191                 }
 192
 193                 if (icount != supplies) {
 194                         dev_err(dev, "%s: Invalid number of elements in %s property (%d) with supplies (%d)\n",
 195                                 __func__, name, icount, supplies);
 196                         ret = -EINVAL;
 197                         goto free_microvolt;
 198                 }
 199
 200                 microamp = kmalloc_array(icount, sizeof(*microamp), GFP_KERNEL);
 201                 if (!microamp) {
 202                         ret = -EINVAL;
 203                         goto free_microvolt;
 204                 }
 205
 206                 ret = of_property_read_u32_array(opp->np, name, microamp,
 207                                                  icount);
 208                 if (ret) {
 209                         dev_err(dev, "%s: error parsing %s: %d\n", __func__,
 210                                 name, ret);
 211                         ret = -EINVAL;
 212                         goto free_microamp;
 213                 }
 214         }
 215
 216         for (i = 0, j = 0; i < supplies; i++) {
 217                 opp->supplies[i].u_volt = microvolt[j++];
 218
 219                 if (vcount == supplies) {
 220                         opp->supplies[i].u_volt_min = opp->supplies[i].u_volt;
 221                         opp->supplies[i].u_volt_max = opp->supplies[i].u_volt;
 222                 } else {
 223                         opp->supplies[i].u_volt_min = microvolt[j++];
 224                         opp->supplies[i].u_volt_max = microvolt[j++];
 225                 }
 226
 227                 if (microamp)
 228                         opp->supplies[i].u_amp = microamp[i];
 229         }
 230
 231 free_microamp:
 232         kfree(microamp);
 233 free_microvolt:
 234         kfree(microvolt);
 235
 236         return ret;
 237 }
 238
 239 /**
 240  * dev_pm_opp_of_remove_table() - Free OPP table entries created from static DT
 241  *                                entries
 242  * @dev:        device pointer used to lookup OPP table.
 243  *
 244  * Free OPPs created using static entries present in DT.
 245  */
 246 void dev_pm_opp_of_remove_table(struct device *dev)
 247 {
 248         _dev_pm_opp_find_and_remove_table(dev, false);
 249 }
 250 EXPORT_SYMBOL_GPL(dev_pm_opp_of_remove_table);
 251
 252 /* Returns opp descriptor node for a device node, caller must
 253  * do of_node_put() */
 254 static struct device_node *_opp_of_get_opp_desc_node(struct device_node *np,
 255                                                      int index)
 256 {
 257         /* "operating-points-v2" can be an array for power domain providers */
 258         return of_parse_phandle(np, "operating-points-v2", index);
 259 }
 260
 261 /* Returns opp descriptor node for a device, caller must do of_node_put() */
 262 struct device_node *dev_pm_opp_of_get_opp_desc_node(struct device *dev)
 263 {
 264         return _opp_of_get_opp_desc_node(dev->of_node, 0);
 265 }
 266 EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_opp_desc_node);
 267
 268 /**
 269  * _opp_add_static_v2() - Allocate static OPPs (As per 'v2' DT bindings)
 270  * @opp_table:  OPP table
 271  * @dev:        device for which we do this operation
 272  * @np:         device node
 273  *
 274  * This function adds an opp definition to the opp table and returns status. The
 275  * opp can be controlled using dev_pm_opp_enable/disable functions and may be
 276  * removed by dev_pm_opp_remove.
 277  *
 278  * Return:
 279  * 0            On success OR
 280  *              Duplicate OPPs (both freq and volt are same) and opp->available
 281  * -EEXIST      Freq are same and volt are different OR
 282  *              Duplicate OPPs (both freq and volt are same) and !opp->available
 283  * -ENOMEM      Memory allocation failure
 284  * -EINVAL      Failed parsing the OPP node
 285  */
 286 static int _opp_add_static_v2(struct opp_table *opp_table, struct device *dev,
 287                               struct device_node *np)
 288 {
 289         struct dev_pm_opp *new_opp;
 290         u64 rate = 0;
 291         u32 val;
 292         int ret;
 293         bool rate_not_available = false;
 294
 295         new_opp = _opp_allocate(opp_table);
 296         if (!new_opp)
 297                 return -ENOMEM;
 298
 299         ret = of_property_read_u64(np, "opp-hz", &rate);
 300         if (ret < 0) {
 301                 /* "opp-hz" is optional for devices like power domains. */
 302                 if (!of_find_property(dev->of_node, "#power-domain-cells",
 303                                       NULL)) {
 304                         dev_err(dev, "%s: opp-hz not found\n", __func__);
 305                         goto free_opp;
 306                 }
 307
 308                 rate_not_available = true;
 309         } else {
 310                 /*
 311                  * Rate is defined as an unsigned long in clk API, and so
 312                  * casting explicitly to its type. Must be fixed once rate is 64
 313                  * bit guaranteed in clk API.
 314                  */
 315                 new_opp->rate = (unsigned long)rate;
 316         }
 317
 318         /* Check if the OPP supports hardware's hierarchy of versions or not */
 319         if (!_opp_is_supported(dev, opp_table, np)) {
 320                 dev_dbg(dev, "OPP not supported by hardware: %llu\n", rate);
 321                 goto free_opp;
 322         }
 323
 324         new_opp->turbo = of_property_read_bool(np, "turbo-mode");
 325
 326         new_opp->np = np;
 327         new_opp->dynamic = false;
 328         new_opp->available = true;
 329
 330         if (!of_property_read_u32(np, "clock-latency-ns", &val))
 331                 new_opp->clock_latency_ns = val;
 332
 333         new_opp->pstate = of_genpd_opp_to_performance_state(dev, np);
 334
 335         ret = opp_parse_supplies(new_opp, dev, opp_table);
 336         if (ret)
 337                 goto free_opp;
 338
 339         ret = _opp_add(dev, new_opp, opp_table, rate_not_available);
 340         if (ret) {
 341                 /* Don't return error for duplicate OPPs */
 342                 if (ret == -EBUSY)
 343                         ret = 0;
 344                 goto free_opp;
 345         }
 346
 347         /* OPP to select on device suspend */
 348         if (of_property_read_bool(np, "opp-suspend")) {
 349                 if (opp_table->suspend_opp) {
 350                         dev_warn(dev, "%s: Multiple suspend OPPs found (%lu %lu)\n",
 351                                  __func__, opp_table->suspend_opp->rate,
 352                                  new_opp->rate);
 353                 } else {
 354                         new_opp->suspend = true;
 355                         opp_table->suspend_opp = new_opp;
 356                 }
 357         }
 358
 359         if (new_opp->clock_latency_ns > opp_table->clock_latency_ns_max)
 360                 opp_table->clock_latency_ns_max = new_opp->clock_latency_ns;
 361
 362         pr_debug("%s: turbo:%d rate:%lu uv:%lu uvmin:%lu uvmax:%lu latency:%lu\n",
 363                  __func__, new_opp->turbo, new_opp->rate,
 364                  new_opp->supplies[0].u_volt, new_opp->supplies[0].u_volt_min,
 365                  new_opp->supplies[0].u_volt_max, new_opp->clock_latency_ns);
 366
 367         /*
 368          * Notify the changes in the availability of the operable
 369          * frequency/voltage list.
 370          */
 371         blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_ADD, new_opp);
 372         return 0;
 373
 374 free_opp:
 375         _opp_free(new_opp);
 376
 377         return ret;
 378 }
 379
 380 /* Initializes OPP tables based on new bindings */
 381 static int _of_add_opp_table_v2(struct device *dev, struct device_node *opp_np)
 382 {
 383         struct device_node *np;
 384         struct opp_table *opp_table;
 385         int ret = 0, count = 0, pstate_count = 0;
 386         struct dev_pm_opp *opp;
 387
 388         opp_table = _managed_opp(opp_np);
 389         if (opp_table) {
 390                 /* OPPs are already managed */
 391                 if (!_add_opp_dev(dev, opp_table))
 392                         ret = -ENOMEM;
 393                 goto put_opp_table;
 394         }
 395
 396         opp_table = dev_pm_opp_get_opp_table(dev);
 397         if (!opp_table)
 398                 return -ENOMEM;
 399
 400         /* We have opp-table node now, iterate over it and add OPPs */
 401         for_each_available_child_of_node(opp_np, np) {
 402                 count++;
 403
 404                 ret = _opp_add_static_v2(opp_table, dev, np);
 405                 if (ret) {
 406                         dev_err(dev, "%s: Failed to add OPP, %d\n", __func__,
 407                                 ret);
 408                         _dev_pm_opp_remove_table(opp_table, dev, false);
 409                         of_node_put(np);
 410                         goto put_opp_table;
 411                 }
 412         }
 413
 414         /* There should be one of more OPP defined */
 415         if (WARN_ON(!count)) {
 416                 ret = -ENOENT;
 417                 goto put_opp_table;
 418         }
 419
 420         list_for_each_entry(opp, &opp_table->opp_list, node)
 421                 pstate_count += !!opp->pstate;
 422
 423         /* Either all or none of the nodes shall have performance state set */
 424         if (pstate_count && pstate_count != count) {
 425                 dev_err(dev, "Not all nodes have performance state set (%d: %d)\n",
 426                         count, pstate_count);
 427                 ret = -ENOENT;
 428                 goto put_opp_table;
 429         }
 430
 431         if (pstate_count)
 432                 opp_table->genpd_performance_state = true;
 433
 434         opp_table->np = opp_np;
 435         if (of_property_read_bool(opp_np, "opp-shared"))
 436                 opp_table->shared_opp = OPP_TABLE_ACCESS_SHARED;
 437         else
 438                 opp_table->shared_opp = OPP_TABLE_ACCESS_EXCLUSIVE;
 439
 440 put_opp_table:
 441         dev_pm_opp_put_opp_table(opp_table);
 442
 443         return ret;
 444 }
 445
 446 /* Initializes OPP tables based on old-deprecated bindings */
 447 static int _of_add_opp_table_v1(struct device *dev)
 448 {
 449         struct opp_table *opp_table;
 450         const struct property *prop;
 451         const __be32 *val;
 452         int nr, ret = 0;
 453
 454         prop = of_find_property(dev->of_node, "operating-points", NULL);
 455         if (!prop)
 456                 return -ENODEV;
 457         if (!prop->value)
 458                 return -ENODATA;
 459
 460         /*
 461          * Each OPP is a set of tuples consisting of frequency and
 462          * voltage like <freq-kHz vol-uV>.
 463          */
 464         nr = prop->length / sizeof(u32);
 465         if (nr % 2) {
 466                 dev_err(dev, "%s: Invalid OPP table\n", __func__);
 467                 return -EINVAL;
 468         }
 469
 470         opp_table = dev_pm_opp_get_opp_table(dev);
 471         if (!opp_table)
 472                 return -ENOMEM;
 473
 474         val = prop->value;
 475         while (nr) {
 476                 unsigned long freq = be32_to_cpup(val++) * 1000;
 477                 unsigned long volt = be32_to_cpup(val++);
 478
 479                 ret = _opp_add_v1(opp_table, dev, freq, volt, false);
 480                 if (ret) {
 481                         dev_err(dev, "%s: Failed to add OPP %ld (%d)\n",
 482                                 __func__, freq, ret);
 483                         _dev_pm_opp_remove_table(opp_table, dev, false);
 484                         break;
 485                 }
 486                 nr -= 2;
 487         }
 488
 489         dev_pm_opp_put_opp_table(opp_table);
 490         return ret;
 491 }
 492
 493 /**
 494  * dev_pm_opp_of_add_table() - Initialize opp table from device tree
 495  * @dev:        device pointer used to lookup OPP table.
 496  *
 497  * Register the initial OPP table with the OPP library for given device.
 498  *
 499  * Return:
 500  * 0            On success OR
 501  *              Duplicate OPPs (both freq and volt are same) and opp->available
 502  * -EEXIST      Freq are same and volt are different OR
 503  *              Duplicate OPPs (both freq and volt are same) and !opp->available
 504  * -ENOMEM      Memory allocation failure
 505  * -ENODEV      when 'operating-points' property is not found or is invalid data
 506  *              in device node.
 507  * -ENODATA     when empty 'operating-points' property is found
 508  * -EINVAL      when invalid entries are found in opp-v2 table
 509  */
 510 int dev_pm_opp_of_add_table(struct device *dev)
 511 {
 512         struct device_node *opp_np;
 513         int ret;
 514
 515         /*
 516          * OPPs have two version of bindings now. The older one is deprecated,
 517          * try for the new binding first.
 518          */
 519         opp_np = dev_pm_opp_of_get_opp_desc_node(dev);
 520         if (!opp_np) {
 521                 /*
 522                  * Try old-deprecated bindings for backward compatibility with
 523                  * older dtbs.
 524                  */
 525                 return _of_add_opp_table_v1(dev);
 526         }
 527
 528         ret = _of_add_opp_table_v2(dev, opp_np);
 529         of_node_put(opp_np);
 530
 531         return ret;
 532 }
 533 EXPORT_SYMBOL_GPL(dev_pm_opp_of_add_table);
 534
 535 /**
 536  * dev_pm_opp_of_add_table_indexed() - Initialize indexed opp table from device tree
 537  * @dev:        device pointer used to lookup OPP table.
 538  * @index:      Index number.
 539  *
 540  * Register the initial OPP table with the OPP library for given device only
 541  * using the "operating-points-v2" property.
 542  *
 543  * Return:
 544  * 0            On success OR
 545  *              Duplicate OPPs (both freq and volt are same) and opp->available
 546  * -EEXIST      Freq are same and volt are different OR
 547  *              Duplicate OPPs (both freq and volt are same) and !opp->available
 548  * -ENOMEM      Memory allocation failure
 549  * -ENODEV      when 'operating-points' property is not found or is invalid data
 550  *              in device node.
 551  * -ENODATA     when empty 'operating-points' property is found
 552  * -EINVAL      when invalid entries are found in opp-v2 table
 553  */
 554 int dev_pm_opp_of_add_table_indexed(struct device *dev, int index)
 555 {
 556         struct device_node *opp_np;
 557         int ret, count;
 558
 559 again:
 560         opp_np = _opp_of_get_opp_desc_node(dev->of_node, index);
 561         if (!opp_np) {
 562                 /*
 563                  * If only one phandle is present, then the same OPP table
 564                  * applies for all index requests.
 565                  */
 566                 count = of_count_phandle_with_args(dev->of_node,
 567                                                    "operating-points-v2", NULL);
 568                 if (count == 1 && index) {
 569                         index = 0;
 570                         goto again;
 571                 }
 572
 573                 return -ENODEV;
 574         }
 575
 576         ret = _of_add_opp_table_v2(dev, opp_np);
 577         of_node_put(opp_np);
 578
 579         return ret;
 580 }
 581 EXPORT_SYMBOL_GPL(dev_pm_opp_of_add_table_indexed);
 582
 583 /* CPU device specific helpers */
 584
 585 /**
 586  * dev_pm_opp_of_cpumask_remove_table() - Removes OPP table for @cpumask
 587  * @cpumask:    cpumask for which OPP table needs to be removed
 588  *
 589  * This removes the OPP tables for CPUs present in the @cpumask.
 590  * This should be used only to remove static entries created from DT.
 591  */
 592 void dev_pm_opp_of_cpumask_remove_table(const struct cpumask *cpumask)
 593 {
 594         _dev_pm_opp_cpumask_remove_table(cpumask, true);
 595 }
 596 EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_remove_table);
 597
 598 /**
 599  * dev_pm_opp_of_cpumask_add_table() - Adds OPP table for @cpumask
 600  * @cpumask:    cpumask for which OPP table needs to be added.
 601  *
 602  * This adds the OPP tables for CPUs present in the @cpumask.
 603  */
 604 int dev_pm_opp_of_cpumask_add_table(const struct cpumask *cpumask)
 605 {
 606         struct device *cpu_dev;
 607         int cpu, ret = 0;
 608
 609         WARN_ON(cpumask_empty(cpumask));
 610
 611         for_each_cpu(cpu, cpumask) {
 612                 cpu_dev = get_cpu_device(cpu);
 613                 if (!cpu_dev) {
 614                         pr_err("%s: failed to get cpu%d device\n", __func__,
 615                                cpu);
 616                         continue;
 617                 }
 618
 619                 ret = dev_pm_opp_of_add_table(cpu_dev);
 620                 if (ret) {
 621                         /*
 622                          * OPP may get registered dynamically, don't print error
 623                          * message here.
 624                          */
 625                         pr_debug("%s: couldn't find opp table for cpu:%d, %d\n",
 626                                  __func__, cpu, ret);
 627
 628                         /* Free all other OPPs */
 629                         dev_pm_opp_of_cpumask_remove_table(cpumask);
 630                         break;
 631                 }
 632         }
 633
 634         return ret;
 635 }
 636 EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_add_table);
 637
 638 /*
 639  * Works only for OPP v2 bindings.
 640  *
 641  * Returns -ENOENT if operating-points-v2 bindings aren't supported.
 642  */
 643 /**
 644  * dev_pm_opp_of_get_sharing_cpus() - Get cpumask of CPUs sharing OPPs with
 645  *                                    @cpu_dev using operating-points-v2
 646  *                                    bindings.
 647  *
 648  * @cpu_dev:    CPU device for which we do this operation
 649  * @cpumask:    cpumask to update with information of sharing CPUs
 650  *
 651  * This updates the @cpumask with CPUs that are sharing OPPs with @cpu_dev.
 652  *
 653  * Returns -ENOENT if operating-points-v2 isn't present for @cpu_dev.
 654  */
 655 int dev_pm_opp_of_get_sharing_cpus(struct device *cpu_dev,
 656                                    struct cpumask *cpumask)
 657 {
 658         struct device_node *np, *tmp_np, *cpu_np;
 659         int cpu, ret = 0;
 660
 661         /* Get OPP descriptor node */
 662         np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);
 663         if (!np) {
 664                 dev_dbg(cpu_dev, "%s: Couldn't find opp node.\n", __func__);
 665                 return -ENOENT;
 666         }
 667
 668         cpumask_set_cpu(cpu_dev->id, cpumask);
 669
 670         /* OPPs are shared ? */
 671         if (!of_property_read_bool(np, "opp-shared"))
 672                 goto put_cpu_node;
 673
 674         for_each_possible_cpu(cpu) {
 675                 if (cpu == cpu_dev->id)
 676                         continue;
 677
 678                 cpu_np = of_cpu_device_node_get(cpu);
 679                 if (!cpu_np) {
 680                         dev_err(cpu_dev, "%s: failed to get cpu%d node\n",
 681                                 __func__, cpu);
 682                         ret = -ENOENT;
 683                         goto put_cpu_node;
 684                 }
 685
 686                 /* Get OPP descriptor node */
 687                 tmp_np = _opp_of_get_opp_desc_node(cpu_np, 0);
 688                 of_node_put(cpu_np);
 689                 if (!tmp_np) {
 690                         pr_err("%pOF: Couldn't find opp node\n", cpu_np);
 691                         ret = -ENOENT;
 692                         goto put_cpu_node;
 693                 }
 694
 695                 /* CPUs are sharing opp node */
 696                 if (np == tmp_np)
 697                         cpumask_set_cpu(cpu, cpumask);
 698
 699                 of_node_put(tmp_np);
 700         }
 701
 702 put_cpu_node:
 703         of_node_put(np);
 704         return ret;
 705 }
 706 EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_sharing_cpus);
 707
 708 /**
 709  * of_dev_pm_opp_find_required_opp() - Search for required OPP.
 710  * @dev: The device whose OPP node is referenced by the 'np' DT node.
 711  * @np: Node that contains the "required-opps" property.
 712  *
 713  * Returns the OPP of the device 'dev', whose phandle is present in the "np"
 714  * node. Although the "required-opps" property supports having multiple
 715  * phandles, this helper routine only parses the very first phandle in the list.
 716  *
 717  * Return: Matching opp, else returns ERR_PTR in case of error and should be
 718  * handled using IS_ERR.
 719  *
 720  * The callers are required to call dev_pm_opp_put() for the returned OPP after
 721  * use.
 722  */
 723 struct dev_pm_opp *of_dev_pm_opp_find_required_opp(struct device *dev,
 724                                                    struct device_node *np)
 725 {
 726         struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ENODEV);
 727         struct device_node *required_np;
 728         struct opp_table *opp_table;
 729
 730         opp_table = _find_opp_table(dev);
 731         if (IS_ERR(opp_table))
 732                 return ERR_CAST(opp_table);
 733
 734         required_np = of_parse_phandle(np, "required-opps", 0);
 735         if (unlikely(!required_np)) {
 736                 dev_err(dev, "Unable to parse required-opps\n");
 737                 goto put_opp_table;
 738         }
 739
 740         mutex_lock(&opp_table->lock);
 741
 742         list_for_each_entry(temp_opp, &opp_table->opp_list, node) {
 743                 if (temp_opp->available && temp_opp->np == required_np) {
 744                         opp = temp_opp;
 745
 746                         /* Increment the reference count of OPP */
 747                         dev_pm_opp_get(opp);
 748                         break;
 749                 }
 750         }
 751
 752         mutex_unlock(&opp_table->lock);
 753
 754         of_node_put(required_np);
 755 put_opp_table:
 756         dev_pm_opp_put_opp_table(opp_table);
 757
 758         return opp;
 759 }
 760 EXPORT_SYMBOL_GPL(of_dev_pm_opp_find_required_opp);
 761
 762 /**
 763  * dev_pm_opp_get_of_node() - Gets the DT node corresponding to an opp
 764  * @opp:        opp for which DT node has to be returned for
 765  *
 766  * Return: DT node corresponding to the opp, else 0 on success.
 767  *
 768  * The caller needs to put the node with of_node_put() after using it.
 769  */
 770 struct device_node *dev_pm_opp_get_of_node(struct dev_pm_opp *opp)
 771 {
 772         if (IS_ERR_OR_NULL(opp)) {
 773                 pr_err("%s: Invalid parameters\n", __func__);
 774                 return NULL;
 775         }
 776
 777         return of_node_get(opp->np);
 778 }
 779 EXPORT_SYMBOL_GPL(dev_pm_opp_get_of_node);