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 = opp_table->regulator_count, vcount, icount, ret, i, j;
 117         struct property *prop = NULL;
 118         char name[NAME_MAX];
 119
 120         /* Search for "opp-microvolt-<name>" */
 121         if (opp_table->prop_name) {
 122                 snprintf(name, sizeof(name), "opp-microvolt-%s",
 123                          opp_table->prop_name);
 124                 prop = of_find_property(opp->np, name, NULL);
 125         }
 126
 127         if (!prop) {
 128                 /* Search for "opp-microvolt" */
 129                 sprintf(name, "opp-microvolt");
 130                 prop = of_find_property(opp->np, name, NULL);
 131
 132                 /* Missing property isn't a problem, but an invalid entry is */
 133                 if (!prop) {
 134                         if (unlikely(supplies == -1)) {
 135                                 /* Initialize regulator_count */
 136                                 opp_table->regulator_count = 0;
 137                                 return 0;
 138                         }
 139
 140                         if (!supplies)
 141                                 return 0;
 142
 143                         dev_err(dev, "%s: opp-microvolt missing although OPP managing regulators\n",
 144                                 __func__);
 145                         return -EINVAL;
 146                 }
 147         }
 148
 149         if (unlikely(supplies == -1)) {
 150                 /* Initialize regulator_count */
 151                 supplies = opp_table->regulator_count = 1;
 152         } else if (unlikely(!supplies)) {
 153                 dev_err(dev, "%s: opp-microvolt wasn't expected\n", __func__);
 154                 return -EINVAL;
 155         }
 156
 157         vcount = of_property_count_u32_elems(opp->np, name);
 158         if (vcount < 0) {
 159                 dev_err(dev, "%s: Invalid %s property (%d)\n",
 160                         __func__, name, vcount);
 161                 return vcount;
 162         }
 163
 164         /* There can be one or three elements per supply */
 165         if (vcount != supplies && vcount != supplies * 3) {
 166                 dev_err(dev, "%s: Invalid number of elements in %s property (%d) with supplies (%d)\n",
 167                         __func__, name, vcount, supplies);
 168                 return -EINVAL;
 169         }
 170
 171         microvolt = kmalloc_array(vcount, sizeof(*microvolt), GFP_KERNEL);
 172         if (!microvolt)
 173                 return -ENOMEM;
 174
 175         ret = of_property_read_u32_array(opp->np, name, microvolt, vcount);
 176         if (ret) {
 177                 dev_err(dev, "%s: error parsing %s: %d\n", __func__, name, ret);
 178                 ret = -EINVAL;
 179                 goto free_microvolt;
 180         }
 181
 182         /* Search for "opp-microamp-<name>" */
 183         prop = NULL;
 184         if (opp_table->prop_name) {
 185                 snprintf(name, sizeof(name), "opp-microamp-%s",
 186                          opp_table->prop_name);
 187                 prop = of_find_property(opp->np, name, NULL);
 188         }
 189
 190         if (!prop) {
 191                 /* Search for "opp-microamp" */
 192                 sprintf(name, "opp-microamp");
 193                 prop = of_find_property(opp->np, name, NULL);
 194         }
 195
 196         if (prop) {
 197                 icount = of_property_count_u32_elems(opp->np, name);
 198                 if (icount < 0) {
 199                         dev_err(dev, "%s: Invalid %s property (%d)\n", __func__,
 200                                 name, icount);
 201                         ret = icount;
 202                         goto free_microvolt;
 203                 }
 204
 205                 if (icount != supplies) {
 206                         dev_err(dev, "%s: Invalid number of elements in %s property (%d) with supplies (%d)\n",
 207                                 __func__, name, icount, supplies);
 208                         ret = -EINVAL;
 209                         goto free_microvolt;
 210                 }
 211
 212                 microamp = kmalloc_array(icount, sizeof(*microamp), GFP_KERNEL);
 213                 if (!microamp) {
 214                         ret = -EINVAL;
 215                         goto free_microvolt;
 216                 }
 217
 218                 ret = of_property_read_u32_array(opp->np, name, microamp,
 219                                                  icount);
 220                 if (ret) {
 221                         dev_err(dev, "%s: error parsing %s: %d\n", __func__,
 222                                 name, ret);
 223                         ret = -EINVAL;
 224                         goto free_microamp;
 225                 }
 226         }
 227
 228         for (i = 0, j = 0; i < supplies; i++) {
 229                 opp->supplies[i].u_volt = microvolt[j++];
 230
 231                 if (vcount == supplies) {
 232                         opp->supplies[i].u_volt_min = opp->supplies[i].u_volt;
 233                         opp->supplies[i].u_volt_max = opp->supplies[i].u_volt;
 234                 } else {
 235                         opp->supplies[i].u_volt_min = microvolt[j++];
 236                         opp->supplies[i].u_volt_max = microvolt[j++];
 237                 }
 238
 239                 if (microamp)
 240                         opp->supplies[i].u_amp = microamp[i];
 241         }
 242
 243 free_microamp:
 244         kfree(microamp);
 245 free_microvolt:
 246         kfree(microvolt);
 247
 248         return ret;
 249 }
 250
 251 /**
 252  * dev_pm_opp_of_remove_table() - Free OPP table entries created from static DT
 253  *                                entries
 254  * @dev:        device pointer used to lookup OPP table.
 255  *
 256  * Free OPPs created using static entries present in DT.
 257  */
 258 void dev_pm_opp_of_remove_table(struct device *dev)
 259 {
 260         _dev_pm_opp_find_and_remove_table(dev, false);
 261 }
 262 EXPORT_SYMBOL_GPL(dev_pm_opp_of_remove_table);
 263
 264 /* Returns opp descriptor node for a device node, caller must
 265  * do of_node_put() */
 266 static struct device_node *_opp_of_get_opp_desc_node(struct device_node *np,
 267                                                      int index)
 268 {
 269         /* "operating-points-v2" can be an array for power domain providers */
 270         return of_parse_phandle(np, "operating-points-v2", index);
 271 }
 272
 273 /* Returns opp descriptor node for a device, caller must do of_node_put() */
 274 struct device_node *dev_pm_opp_of_get_opp_desc_node(struct device *dev)
 275 {
 276         return _opp_of_get_opp_desc_node(dev->of_node, 0);
 277 }
 278 EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_opp_desc_node);
 279
 280 /**
 281  * _opp_add_static_v2() - Allocate static OPPs (As per 'v2' DT bindings)
 282  * @opp_table:  OPP table
 283  * @dev:        device for which we do this operation
 284  * @np:         device node
 285  *
 286  * This function adds an opp definition to the opp table and returns status. The
 287  * opp can be controlled using dev_pm_opp_enable/disable functions and may be
 288  * removed by dev_pm_opp_remove.
 289  *
 290  * Return:
 291  * 0            On success OR
 292  *              Duplicate OPPs (both freq and volt are same) and opp->available
 293  * -EEXIST      Freq are same and volt are different OR
 294  *              Duplicate OPPs (both freq and volt are same) and !opp->available
 295  * -ENOMEM      Memory allocation failure
 296  * -EINVAL      Failed parsing the OPP node
 297  */
 298 static int _opp_add_static_v2(struct opp_table *opp_table, struct device *dev,
 299                               struct device_node *np)
 300 {
 301         struct dev_pm_opp *new_opp;
 302         u64 rate = 0;
 303         u32 val;
 304         int ret;
 305         bool rate_not_available = false;
 306
 307         new_opp = _opp_allocate(opp_table);
 308         if (!new_opp)
 309                 return -ENOMEM;
 310
 311         ret = of_property_read_u64(np, "opp-hz", &rate);
 312         if (ret < 0) {
 313                 /* "opp-hz" is optional for devices like power domains. */
 314                 if (!of_find_property(dev->of_node, "#power-domain-cells",
 315                                       NULL)) {
 316                         dev_err(dev, "%s: opp-hz not found\n", __func__);
 317                         goto free_opp;
 318                 }
 319
 320                 rate_not_available = true;
 321         } else {
 322                 /*
 323                  * Rate is defined as an unsigned long in clk API, and so
 324                  * casting explicitly to its type. Must be fixed once rate is 64
 325                  * bit guaranteed in clk API.
 326                  */
 327                 new_opp->rate = (unsigned long)rate;
 328         }
 329
 330         /* Check if the OPP supports hardware's hierarchy of versions or not */
 331         if (!_opp_is_supported(dev, opp_table, np)) {
 332                 dev_dbg(dev, "OPP not supported by hardware: %llu\n", rate);
 333                 goto free_opp;
 334         }
 335
 336         new_opp->turbo = of_property_read_bool(np, "turbo-mode");
 337
 338         new_opp->np = np;
 339         new_opp->dynamic = false;
 340         new_opp->available = true;
 341
 342         if (!of_property_read_u32(np, "clock-latency-ns", &val))
 343                 new_opp->clock_latency_ns = val;
 344
 345         new_opp->pstate = of_genpd_opp_to_performance_state(dev, np);
 346
 347         ret = opp_parse_supplies(new_opp, dev, opp_table);
 348         if (ret)
 349                 goto free_opp;
 350
 351         ret = _opp_add(dev, new_opp, opp_table, rate_not_available);
 352         if (ret) {
 353                 /* Don't return error for duplicate OPPs */
 354                 if (ret == -EBUSY)
 355                         ret = 0;
 356                 goto free_opp;
 357         }
 358
 359         /* OPP to select on device suspend */
 360         if (of_property_read_bool(np, "opp-suspend")) {
 361                 if (opp_table->suspend_opp) {
 362                         dev_warn(dev, "%s: Multiple suspend OPPs found (%lu %lu)\n",
 363                                  __func__, opp_table->suspend_opp->rate,
 364                                  new_opp->rate);
 365                 } else {
 366                         new_opp->suspend = true;
 367                         opp_table->suspend_opp = new_opp;
 368                 }
 369         }
 370
 371         if (new_opp->clock_latency_ns > opp_table->clock_latency_ns_max)
 372                 opp_table->clock_latency_ns_max = new_opp->clock_latency_ns;
 373
 374         pr_debug("%s: turbo:%d rate:%lu uv:%lu uvmin:%lu uvmax:%lu latency:%lu\n",
 375                  __func__, new_opp->turbo, new_opp->rate,
 376                  new_opp->supplies[0].u_volt, new_opp->supplies[0].u_volt_min,
 377                  new_opp->supplies[0].u_volt_max, new_opp->clock_latency_ns);
 378
 379         /*
 380          * Notify the changes in the availability of the operable
 381          * frequency/voltage list.
 382          */
 383         blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_ADD, new_opp);
 384         return 0;
 385
 386 free_opp:
 387         _opp_free(new_opp);
 388
 389         return ret;
 390 }
 391
 392 /* Initializes OPP tables based on new bindings */
 393 static int _of_add_opp_table_v2(struct device *dev, struct device_node *opp_np)
 394 {
 395         struct device_node *np;
 396         struct opp_table *opp_table;
 397         int ret = 0, count = 0, pstate_count = 0;
 398         struct dev_pm_opp *opp;
 399
 400         opp_table = _managed_opp(opp_np);
 401         if (opp_table) {
 402                 /* OPPs are already managed */
 403                 if (!_add_opp_dev(dev, opp_table))
 404                         ret = -ENOMEM;
 405                 goto put_opp_table;
 406         }
 407
 408         opp_table = dev_pm_opp_get_opp_table(dev);
 409         if (!opp_table)
 410                 return -ENOMEM;
 411
 412         /* We have opp-table node now, iterate over it and add OPPs */
 413         for_each_available_child_of_node(opp_np, np) {
 414                 count++;
 415
 416                 ret = _opp_add_static_v2(opp_table, dev, np);
 417                 if (ret) {
 418                         dev_err(dev, "%s: Failed to add OPP, %d\n", __func__,
 419                                 ret);
 420                         _dev_pm_opp_remove_table(opp_table, dev, false);
 421                         of_node_put(np);
 422                         goto put_opp_table;
 423                 }
 424         }
 425
 426         /* There should be one or more OPPs defined */
 427         if (!count) {
 428                 dev_err(dev, "%s: no supported OPPs", __func__);
 429                 ret = -ENOENT;
 430                 goto put_opp_table;
 431         }
 432
 433         list_for_each_entry(opp, &opp_table->opp_list, node)
 434                 pstate_count += !!opp->pstate;
 435
 436         /* Either all or none of the nodes shall have performance state set */
 437         if (pstate_count && pstate_count != count) {
 438                 dev_err(dev, "Not all nodes have performance state set (%d: %d)\n",
 439                         count, pstate_count);
 440                 ret = -ENOENT;
 441                 _dev_pm_opp_remove_table(opp_table, dev, false);
 442                 goto put_opp_table;
 443         }
 444
 445         if (pstate_count)
 446                 opp_table->genpd_performance_state = true;
 447
 448         opp_table->np = opp_np;
 449         if (of_property_read_bool(opp_np, "opp-shared"))
 450                 opp_table->shared_opp = OPP_TABLE_ACCESS_SHARED;
 451         else
 452                 opp_table->shared_opp = OPP_TABLE_ACCESS_EXCLUSIVE;
 453
 454 put_opp_table:
 455         dev_pm_opp_put_opp_table(opp_table);
 456
 457         return ret;
 458 }
 459
 460 /* Initializes OPP tables based on old-deprecated bindings */
 461 static int _of_add_opp_table_v1(struct device *dev)
 462 {
 463         struct opp_table *opp_table;
 464         const struct property *prop;
 465         const __be32 *val;
 466         int nr, ret = 0;
 467
 468         prop = of_find_property(dev->of_node, "operating-points", NULL);
 469         if (!prop)
 470                 return -ENODEV;
 471         if (!prop->value)
 472                 return -ENODATA;
 473
 474         /*
 475          * Each OPP is a set of tuples consisting of frequency and
 476          * voltage like <freq-kHz vol-uV>.
 477          */
 478         nr = prop->length / sizeof(u32);
 479         if (nr % 2) {
 480                 dev_err(dev, "%s: Invalid OPP table\n", __func__);
 481                 return -EINVAL;
 482         }
 483
 484         opp_table = dev_pm_opp_get_opp_table(dev);
 485         if (!opp_table)
 486                 return -ENOMEM;
 487
 488         val = prop->value;
 489         while (nr) {
 490                 unsigned long freq = be32_to_cpup(val++) * 1000;
 491                 unsigned long volt = be32_to_cpup(val++);
 492
 493                 ret = _opp_add_v1(opp_table, dev, freq, volt, false);
 494                 if (ret) {
 495                         dev_err(dev, "%s: Failed to add OPP %ld (%d)\n",
 496                                 __func__, freq, ret);
 497                         _dev_pm_opp_remove_table(opp_table, dev, false);
 498                         break;
 499                 }
 500                 nr -= 2;
 501         }
 502
 503         dev_pm_opp_put_opp_table(opp_table);
 504         return ret;
 505 }
 506
 507 /**
 508  * dev_pm_opp_of_add_table() - Initialize opp table from device tree
 509  * @dev:        device pointer used to lookup OPP table.
 510  *
 511  * Register the initial OPP table with the OPP library for given device.
 512  *
 513  * Return:
 514  * 0            On success OR
 515  *              Duplicate OPPs (both freq and volt are same) and opp->available
 516  * -EEXIST      Freq are same and volt are different OR
 517  *              Duplicate OPPs (both freq and volt are same) and !opp->available
 518  * -ENOMEM      Memory allocation failure
 519  * -ENODEV      when 'operating-points' property is not found or is invalid data
 520  *              in device node.
 521  * -ENODATA     when empty 'operating-points' property is found
 522  * -EINVAL      when invalid entries are found in opp-v2 table
 523  */
 524 int dev_pm_opp_of_add_table(struct device *dev)
 525 {
 526         struct device_node *opp_np;
 527         int ret;
 528
 529         /*
 530          * OPPs have two version of bindings now. The older one is deprecated,
 531          * try for the new binding first.
 532          */
 533         opp_np = dev_pm_opp_of_get_opp_desc_node(dev);
 534         if (!opp_np) {
 535                 /*
 536                  * Try old-deprecated bindings for backward compatibility with
 537                  * older dtbs.
 538                  */
 539                 return _of_add_opp_table_v1(dev);
 540         }
 541
 542         ret = _of_add_opp_table_v2(dev, opp_np);
 543         of_node_put(opp_np);
 544
 545         return ret;
 546 }
 547 EXPORT_SYMBOL_GPL(dev_pm_opp_of_add_table);
 548
 549 /**
 550  * dev_pm_opp_of_add_table_indexed() - Initialize indexed opp table from device tree
 551  * @dev:        device pointer used to lookup OPP table.
 552  * @index:      Index number.
 553  *
 554  * Register the initial OPP table with the OPP library for given device only
 555  * using the "operating-points-v2" property.
 556  *
 557  * Return:
 558  * 0            On success OR
 559  *              Duplicate OPPs (both freq and volt are same) and opp->available
 560  * -EEXIST      Freq are same and volt are different OR
 561  *              Duplicate OPPs (both freq and volt are same) and !opp->available
 562  * -ENOMEM      Memory allocation failure
 563  * -ENODEV      when 'operating-points' property is not found or is invalid data
 564  *              in device node.
 565  * -ENODATA     when empty 'operating-points' property is found
 566  * -EINVAL      when invalid entries are found in opp-v2 table
 567  */
 568 int dev_pm_opp_of_add_table_indexed(struct device *dev, int index)
 569 {
 570         struct device_node *opp_np;
 571         int ret, count;
 572
 573 again:
 574         opp_np = _opp_of_get_opp_desc_node(dev->of_node, index);
 575         if (!opp_np) {
 576                 /*
 577                  * If only one phandle is present, then the same OPP table
 578                  * applies for all index requests.
 579                  */
 580                 count = of_count_phandle_with_args(dev->of_node,
 581                                                    "operating-points-v2", NULL);
 582                 if (count == 1 && index) {
 583                         index = 0;
 584                         goto again;
 585                 }
 586
 587                 return -ENODEV;
 588         }
 589
 590         ret = _of_add_opp_table_v2(dev, opp_np);
 591         of_node_put(opp_np);
 592
 593         return ret;
 594 }
 595 EXPORT_SYMBOL_GPL(dev_pm_opp_of_add_table_indexed);
 596
 597 /* CPU device specific helpers */
 598
 599 /**
 600  * dev_pm_opp_of_cpumask_remove_table() - Removes OPP table for @cpumask
 601  * @cpumask:    cpumask for which OPP table needs to be removed
 602  *
 603  * This removes the OPP tables for CPUs present in the @cpumask.
 604  * This should be used only to remove static entries created from DT.
 605  */
 606 void dev_pm_opp_of_cpumask_remove_table(const struct cpumask *cpumask)
 607 {
 608         _dev_pm_opp_cpumask_remove_table(cpumask, true);
 609 }
 610 EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_remove_table);
 611
 612 /**
 613  * dev_pm_opp_of_cpumask_add_table() - Adds OPP table for @cpumask
 614  * @cpumask:    cpumask for which OPP table needs to be added.
 615  *
 616  * This adds the OPP tables for CPUs present in the @cpumask.
 617  */
 618 int dev_pm_opp_of_cpumask_add_table(const struct cpumask *cpumask)
 619 {
 620         struct device *cpu_dev;
 621         int cpu, ret = 0;
 622
 623         WARN_ON(cpumask_empty(cpumask));
 624
 625         for_each_cpu(cpu, cpumask) {
 626                 cpu_dev = get_cpu_device(cpu);
 627                 if (!cpu_dev) {
 628                         pr_err("%s: failed to get cpu%d device\n", __func__,
 629                                cpu);
 630                         continue;
 631                 }
 632
 633                 ret = dev_pm_opp_of_add_table(cpu_dev);
 634                 if (ret) {
 635                         /*
 636                          * OPP may get registered dynamically, don't print error
 637                          * message here.
 638                          */
 639                         pr_debug("%s: couldn't find opp table for cpu:%d, %d\n",
 640                                  __func__, cpu, ret);
 641
 642                         /* Free all other OPPs */
 643                         dev_pm_opp_of_cpumask_remove_table(cpumask);
 644                         break;
 645                 }
 646         }
 647
 648         return ret;
 649 }
 650 EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_add_table);
 651
 652 /*
 653  * Works only for OPP v2 bindings.
 654  *
 655  * Returns -ENOENT if operating-points-v2 bindings aren't supported.
 656  */
 657 /**
 658  * dev_pm_opp_of_get_sharing_cpus() - Get cpumask of CPUs sharing OPPs with
 659  *                                    @cpu_dev using operating-points-v2
 660  *                                    bindings.
 661  *
 662  * @cpu_dev:    CPU device for which we do this operation
 663  * @cpumask:    cpumask to update with information of sharing CPUs
 664  *
 665  * This updates the @cpumask with CPUs that are sharing OPPs with @cpu_dev.
 666  *
 667  * Returns -ENOENT if operating-points-v2 isn't present for @cpu_dev.
 668  */
 669 int dev_pm_opp_of_get_sharing_cpus(struct device *cpu_dev,
 670                                    struct cpumask *cpumask)
 671 {
 672         struct device_node *np, *tmp_np, *cpu_np;
 673         int cpu, ret = 0;
 674
 675         /* Get OPP descriptor node */
 676         np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);
 677         if (!np) {
 678                 dev_dbg(cpu_dev, "%s: Couldn't find opp node.\n", __func__);
 679                 return -ENOENT;
 680         }
 681
 682         cpumask_set_cpu(cpu_dev->id, cpumask);
 683
 684         /* OPPs are shared ? */
 685         if (!of_property_read_bool(np, "opp-shared"))
 686                 goto put_cpu_node;
 687
 688         for_each_possible_cpu(cpu) {
 689                 if (cpu == cpu_dev->id)
 690                         continue;
 691
 692                 cpu_np = of_cpu_device_node_get(cpu);
 693                 if (!cpu_np) {
 694                         dev_err(cpu_dev, "%s: failed to get cpu%d node\n",
 695                                 __func__, cpu);
 696                         ret = -ENOENT;
 697                         goto put_cpu_node;
 698                 }
 699
 700                 /* Get OPP descriptor node */
 701                 tmp_np = _opp_of_get_opp_desc_node(cpu_np, 0);
 702                 of_node_put(cpu_np);
 703                 if (!tmp_np) {
 704                         pr_err("%pOF: Couldn't find opp node\n", cpu_np);
 705                         ret = -ENOENT;
 706                         goto put_cpu_node;
 707                 }
 708
 709                 /* CPUs are sharing opp node */
 710                 if (np == tmp_np)
 711                         cpumask_set_cpu(cpu, cpumask);
 712
 713                 of_node_put(tmp_np);
 714         }
 715
 716 put_cpu_node:
 717         of_node_put(np);
 718         return ret;
 719 }
 720 EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_sharing_cpus);
 721
 722 /**
 723  * of_dev_pm_opp_find_required_opp() - Search for required OPP.
 724  * @dev: The device whose OPP node is referenced by the 'np' DT node.
 725  * @np: Node that contains the "required-opps" property.
 726  *
 727  * Returns the OPP of the device 'dev', whose phandle is present in the "np"
 728  * node. Although the "required-opps" property supports having multiple
 729  * phandles, this helper routine only parses the very first phandle in the list.
 730  *
 731  * Return: Matching opp, else returns ERR_PTR in case of error and should be
 732  * handled using IS_ERR.
 733  *
 734  * The callers are required to call dev_pm_opp_put() for the returned OPP after
 735  * use.
 736  */
 737 struct dev_pm_opp *of_dev_pm_opp_find_required_opp(struct device *dev,
 738                                                    struct device_node *np)
 739 {
 740         struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ENODEV);
 741         struct device_node *required_np;
 742         struct opp_table *opp_table;
 743
 744         opp_table = _find_opp_table(dev);
 745         if (IS_ERR(opp_table))
 746                 return ERR_CAST(opp_table);
 747
 748         required_np = of_parse_phandle(np, "required-opps", 0);
 749         if (unlikely(!required_np)) {
 750                 dev_err(dev, "Unable to parse required-opps\n");
 751                 goto put_opp_table;
 752         }
 753
 754         mutex_lock(&opp_table->lock);
 755
 756         list_for_each_entry(temp_opp, &opp_table->opp_list, node) {
 757                 if (temp_opp->available && temp_opp->np == required_np) {
 758                         opp = temp_opp;
 759
 760                         /* Increment the reference count of OPP */
 761                         dev_pm_opp_get(opp);
 762                         break;
 763                 }
 764         }
 765
 766         mutex_unlock(&opp_table->lock);
 767
 768         of_node_put(required_np);
 769 put_opp_table:
 770         dev_pm_opp_put_opp_table(opp_table);
 771
 772         return opp;
 773 }
 774 EXPORT_SYMBOL_GPL(of_dev_pm_opp_find_required_opp);
 775
 776 /**
 777  * dev_pm_opp_get_of_node() - Gets the DT node corresponding to an opp
 778  * @opp:        opp for which DT node has to be returned for
 779  *
 780  * Return: DT node corresponding to the opp, else 0 on success.
 781  *
 782  * The caller needs to put the node with of_node_put() after using it.
 783  */
 784 struct device_node *dev_pm_opp_get_of_node(struct dev_pm_opp *opp)
 785 {
 786         if (IS_ERR_OR_NULL(opp)) {
 787                 pr_err("%s: Invalid parameters\n", __func__);
 788                 return NULL;
 789         }
 790
 791         return of_node_get(opp->np);
 792 }
 793 EXPORT_SYMBOL_GPL(dev_pm_opp_get_of_node);