drivers/acpi/property.c

   1 /*
   2  * ACPI device specific properties support.
   3  *
   4  * Copyright (C) 2014, Intel Corporation
   5  * All rights reserved.
   6  *
   7  * Authors: Mika Westerberg <mika.westerberg@linux.intel.com>
   8  *          Darren Hart <dvhart@linux.intel.com>
   9  *          Rafael J. Wysocki <rafael.j.wysocki@intel.com>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  */
  15
  16 #include <linux/acpi.h>
  17 #include <linux/device.h>
  18 #include <linux/export.h>
  19
  20 #include "internal.h"
  21
  22 static int acpi_data_get_property_array(struct acpi_device_data *data,
  23                                         const char *name,
  24                                         acpi_object_type type,
  25                                         const union acpi_object **obj);
  26
  27 /* ACPI _DSD device properties UUID: daffd814-6eba-4d8c-8a91-bc9bbf4aa301 */
  28 static const u8 prp_uuid[16] = {
  29         0x14, 0xd8, 0xff, 0xda, 0xba, 0x6e, 0x8c, 0x4d,
  30         0x8a, 0x91, 0xbc, 0x9b, 0xbf, 0x4a, 0xa3, 0x01
  31 };
  32 /* ACPI _DSD data subnodes UUID: dbb8e3e6-5886-4ba6-8795-1319f52a966b */
  33 static const u8 ads_uuid[16] = {
  34         0xe6, 0xe3, 0xb8, 0xdb, 0x86, 0x58, 0xa6, 0x4b,
  35         0x87, 0x95, 0x13, 0x19, 0xf5, 0x2a, 0x96, 0x6b
  36 };
  37
  38 static bool acpi_enumerate_nondev_subnodes(acpi_handle scope,
  39                                            const union acpi_object *desc,
  40                                            struct acpi_device_data *data);
  41 static bool acpi_extract_properties(const union acpi_object *desc,
  42                                     struct acpi_device_data *data);
  43
  44 static bool acpi_nondev_subnode_extract(const union acpi_object *desc,
  45                                         acpi_handle handle,
  46                                         const union acpi_object *link,
  47                                         struct list_head *list)
  48 {
  49         struct acpi_data_node *dn;
  50         bool result;
  51
  52         dn = kzalloc(sizeof(*dn), GFP_KERNEL);
  53         if (!dn)
  54                 return false;
  55
  56         dn->name = link->package.elements[0].string.pointer;
  57         dn->fwnode.type = FWNODE_ACPI_DATA;
  58         INIT_LIST_HEAD(&dn->data.subnodes);
  59
  60         result = acpi_extract_properties(desc, &dn->data);
  61
  62         if (handle) {
  63                 acpi_handle scope;
  64                 acpi_status status;
  65
  66                 /*
  67                  * The scope for the subnode object lookup is the one of the
  68                  * namespace node (device) containing the object that has
  69                  * returned the package.  That is, it's the scope of that
  70                  * object's parent.
  71                  */
  72                 status = acpi_get_parent(handle, &scope);
  73                 if (ACPI_SUCCESS(status)
  74                     && acpi_enumerate_nondev_subnodes(scope, desc, &dn->data))
  75                         result = true;
  76         } else if (acpi_enumerate_nondev_subnodes(NULL, desc, &dn->data)) {
  77                 result = true;
  78         }
  79
  80         if (result) {
  81                 dn->handle = handle;
  82                 dn->data.pointer = desc;
  83                 list_add_tail(&dn->sibling, list);
  84                 return true;
  85         }
  86
  87         kfree(dn);
  88         acpi_handle_debug(handle, "Invalid properties/subnodes data, skipping\n");
  89         return false;
  90 }
  91
  92 static bool acpi_nondev_subnode_data_ok(acpi_handle handle,
  93                                         const union acpi_object *link,
  94                                         struct list_head *list)
  95 {
  96         struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
  97         acpi_status status;
  98
  99         status = acpi_evaluate_object_typed(handle, NULL, NULL, &buf,
 100                                             ACPI_TYPE_PACKAGE);
 101         if (ACPI_FAILURE(status))
 102                 return false;
 103
 104         if (acpi_nondev_subnode_extract(buf.pointer, handle, link, list))
 105                 return true;
 106
 107         ACPI_FREE(buf.pointer);
 108         return false;
 109 }
 110
 111 static bool acpi_nondev_subnode_ok(acpi_handle scope,
 112                                    const union acpi_object *link,
 113                                    struct list_head *list)
 114 {
 115         acpi_handle handle;
 116         acpi_status status;
 117
 118         if (!scope)
 119                 return false;
 120
 121         status = acpi_get_handle(scope, link->package.elements[1].string.pointer,
 122                                  &handle);
 123         if (ACPI_FAILURE(status))
 124                 return false;
 125
 126         return acpi_nondev_subnode_data_ok(handle, link, list);
 127 }
 128
 129 static int acpi_add_nondev_subnodes(acpi_handle scope,
 130                                     const union acpi_object *links,
 131                                     struct list_head *list)
 132 {
 133         bool ret = false;
 134         int i;
 135
 136         for (i = 0; i < links->package.count; i++) {
 137                 const union acpi_object *link, *desc;
 138                 acpi_handle handle;
 139                 bool result;
 140
 141                 link = &links->package.elements[i];
 142                 /* Only two elements allowed. */
 143                 if (link->package.count != 2)
 144                         continue;
 145
 146                 /* The first one must be a string. */
 147                 if (link->package.elements[0].type != ACPI_TYPE_STRING)
 148                         continue;
 149
 150                 /* The second one may be a string, a reference or a package. */
 151                 switch (link->package.elements[1].type) {
 152                 case ACPI_TYPE_STRING:
 153                         result = acpi_nondev_subnode_ok(scope, link, list);
 154                         break;
 155                 case ACPI_TYPE_LOCAL_REFERENCE:
 156                         handle = link->package.elements[1].reference.handle;
 157                         result = acpi_nondev_subnode_data_ok(handle, link, list);
 158                         break;
 159                 case ACPI_TYPE_PACKAGE:
 160                         desc = &link->package.elements[1];
 161                         result = acpi_nondev_subnode_extract(desc, NULL, link, list);
 162                         break;
 163                 default:
 164                         result = false;
 165                         break;
 166                 }
 167                 ret = ret || result;
 168         }
 169
 170         return ret;
 171 }
 172
 173 static bool acpi_enumerate_nondev_subnodes(acpi_handle scope,
 174                                            const union acpi_object *desc,
 175                                            struct acpi_device_data *data)
 176 {
 177         int i;
 178
 179         /* Look for the ACPI data subnodes UUID. */
 180         for (i = 0; i < desc->package.count; i += 2) {
 181                 const union acpi_object *uuid, *links;
 182
 183                 uuid = &desc->package.elements[i];
 184                 links = &desc->package.elements[i + 1];
 185
 186                 /*
 187                  * The first element must be a UUID and the second one must be
 188                  * a package.
 189                  */
 190                 if (uuid->type != ACPI_TYPE_BUFFER || uuid->buffer.length != 16
 191                     || links->type != ACPI_TYPE_PACKAGE)
 192                         break;
 193
 194                 if (memcmp(uuid->buffer.pointer, ads_uuid, sizeof(ads_uuid)))
 195                         continue;
 196
 197                 return acpi_add_nondev_subnodes(scope, links, &data->subnodes);
 198         }
 199
 200         return false;
 201 }
 202
 203 static bool acpi_property_value_ok(const union acpi_object *value)
 204 {
 205         int j;
 206
 207         /*
 208          * The value must be an integer, a string, a reference, or a package
 209          * whose every element must be an integer, a string, or a reference.
 210          */
 211         switch (value->type) {
 212         case ACPI_TYPE_INTEGER:
 213         case ACPI_TYPE_STRING:
 214         case ACPI_TYPE_LOCAL_REFERENCE:
 215                 return true;
 216
 217         case ACPI_TYPE_PACKAGE:
 218                 for (j = 0; j < value->package.count; j++)
 219                         switch (value->package.elements[j].type) {
 220                         case ACPI_TYPE_INTEGER:
 221                         case ACPI_TYPE_STRING:
 222                         case ACPI_TYPE_LOCAL_REFERENCE:
 223                                 continue;
 224
 225                         default:
 226                                 return false;
 227                         }
 228
 229                 return true;
 230         }
 231         return false;
 232 }
 233
 234 static bool acpi_properties_format_valid(const union acpi_object *properties)
 235 {
 236         int i;
 237
 238         for (i = 0; i < properties->package.count; i++) {
 239                 const union acpi_object *property;
 240
 241                 property = &properties->package.elements[i];
 242                 /*
 243                  * Only two elements allowed, the first one must be a string and
 244                  * the second one has to satisfy certain conditions.
 245                  */
 246                 if (property->package.count != 2
 247                     || property->package.elements[0].type != ACPI_TYPE_STRING
 248                     || !acpi_property_value_ok(&property->package.elements[1]))
 249                         return false;
 250         }
 251         return true;
 252 }
 253
 254 static void acpi_init_of_compatible(struct acpi_device *adev)
 255 {
 256         const union acpi_object *of_compatible;
 257         int ret;
 258
 259         ret = acpi_data_get_property_array(&adev->data, "compatible",
 260                                            ACPI_TYPE_STRING, &of_compatible);
 261         if (ret) {
 262                 ret = acpi_dev_get_property(adev, "compatible",
 263                                             ACPI_TYPE_STRING, &of_compatible);
 264                 if (ret) {
 265                         if (adev->parent
 266                             && adev->parent->flags.of_compatible_ok)
 267                                 goto out;
 268
 269                         return;
 270                 }
 271         }
 272         adev->data.of_compatible = of_compatible;
 273
 274  out:
 275         adev->flags.of_compatible_ok = 1;
 276 }
 277
 278 static bool acpi_extract_properties(const union acpi_object *desc,
 279                                     struct acpi_device_data *data)
 280 {
 281         int i;
 282
 283         if (desc->package.count % 2)
 284                 return false;
 285
 286         /* Look for the device properties UUID. */
 287         for (i = 0; i < desc->package.count; i += 2) {
 288                 const union acpi_object *uuid, *properties;
 289
 290                 uuid = &desc->package.elements[i];
 291                 properties = &desc->package.elements[i + 1];
 292
 293                 /*
 294                  * The first element must be a UUID and the second one must be
 295                  * a package.
 296                  */
 297                 if (uuid->type != ACPI_TYPE_BUFFER || uuid->buffer.length != 16
 298                     || properties->type != ACPI_TYPE_PACKAGE)
 299                         break;
 300
 301                 if (memcmp(uuid->buffer.pointer, prp_uuid, sizeof(prp_uuid)))
 302                         continue;
 303
 304                 /*
 305                  * We found the matching UUID. Now validate the format of the
 306                  * package immediately following it.
 307                  */
 308                 if (!acpi_properties_format_valid(properties))
 309                         break;
 310
 311                 data->properties = properties;
 312                 return true;
 313         }
 314
 315         return false;
 316 }
 317
 318 void acpi_init_properties(struct acpi_device *adev)
 319 {
 320         struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
 321         struct acpi_hardware_id *hwid;
 322         acpi_status status;
 323         bool acpi_of = false;
 324
 325         INIT_LIST_HEAD(&adev->data.subnodes);
 326
 327         /*
 328          * Check if ACPI_DT_NAMESPACE_HID is present and inthat case we fill in
 329          * Device Tree compatible properties for this device.
 330          */
 331         list_for_each_entry(hwid, &adev->pnp.ids, list) {
 332                 if (!strcmp(hwid->id, ACPI_DT_NAMESPACE_HID)) {
 333                         acpi_of = true;
 334                         break;
 335                 }
 336         }
 337
 338         status = acpi_evaluate_object_typed(adev->handle, "_DSD", NULL, &buf,
 339                                             ACPI_TYPE_PACKAGE);
 340         if (ACPI_FAILURE(status))
 341                 goto out;
 342
 343         if (acpi_extract_properties(buf.pointer, &adev->data)) {
 344                 adev->data.pointer = buf.pointer;
 345                 if (acpi_of)
 346                         acpi_init_of_compatible(adev);
 347         }
 348         if (acpi_enumerate_nondev_subnodes(adev->handle, buf.pointer, &adev->data))
 349                 adev->data.pointer = buf.pointer;
 350
 351         if (!adev->data.pointer) {
 352                 acpi_handle_debug(adev->handle, "Invalid _DSD data, skipping\n");
 353                 ACPI_FREE(buf.pointer);
 354         }
 355
 356  out:
 357         if (acpi_of && !adev->flags.of_compatible_ok)
 358                 acpi_handle_info(adev->handle,
 359                          ACPI_DT_NAMESPACE_HID " requires 'compatible' property\n");
 360 }
 361
 362 static void acpi_destroy_nondev_subnodes(struct list_head *list)
 363 {
 364         struct acpi_data_node *dn, *next;
 365
 366         if (list_empty(list))
 367                 return;
 368
 369         list_for_each_entry_safe_reverse(dn, next, list, sibling) {
 370                 acpi_destroy_nondev_subnodes(&dn->data.subnodes);
 371                 wait_for_completion(&dn->kobj_done);
 372                 list_del(&dn->sibling);
 373                 ACPI_FREE((void *)dn->data.pointer);
 374                 kfree(dn);
 375         }
 376 }
 377
 378 void acpi_free_properties(struct acpi_device *adev)
 379 {
 380         acpi_destroy_nondev_subnodes(&adev->data.subnodes);
 381         ACPI_FREE((void *)adev->data.pointer);
 382         adev->data.of_compatible = NULL;
 383         adev->data.pointer = NULL;
 384         adev->data.properties = NULL;
 385 }
 386
 387 /**
 388  * acpi_data_get_property - return an ACPI property with given name
 389  * @data: ACPI device deta object to get the property from
 390  * @name: Name of the property
 391  * @type: Expected property type
 392  * @obj: Location to store the property value (if not %NULL)
 393  *
 394  * Look up a property with @name and store a pointer to the resulting ACPI
 395  * object at the location pointed to by @obj if found.
 396  *
 397  * Callers must not attempt to free the returned objects.  These objects will be
 398  * freed by the ACPI core automatically during the removal of @data.
 399  *
 400  * Return: %0 if property with @name has been found (success),
 401  *         %-EINVAL if the arguments are invalid,
 402  *         %-EINVAL if the property doesn't exist,
 403  *         %-EPROTO if the property value type doesn't match @type.
 404  */
 405 static int acpi_data_get_property(struct acpi_device_data *data,
 406                                   const char *name, acpi_object_type type,
 407                                   const union acpi_object **obj)
 408 {
 409         const union acpi_object *properties;
 410         int i;
 411
 412         if (!data || !name)
 413                 return -EINVAL;
 414
 415         if (!data->pointer || !data->properties)
 416                 return -EINVAL;
 417
 418         properties = data->properties;
 419         for (i = 0; i < properties->package.count; i++) {
 420                 const union acpi_object *propname, *propvalue;
 421                 const union acpi_object *property;
 422
 423                 property = &properties->package.elements[i];
 424
 425                 propname = &property->package.elements[0];
 426                 propvalue = &property->package.elements[1];
 427
 428                 if (!strcmp(name, propname->string.pointer)) {
 429                         if (type != ACPI_TYPE_ANY && propvalue->type != type)
 430                                 return -EPROTO;
 431                         if (obj)
 432                                 *obj = propvalue;
 433
 434                         return 0;
 435                 }
 436         }
 437         return -EINVAL;
 438 }
 439
 440 /**
 441  * acpi_dev_get_property - return an ACPI property with given name.
 442  * @adev: ACPI device to get the property from.
 443  * @name: Name of the property.
 444  * @type: Expected property type.
 445  * @obj: Location to store the property value (if not %NULL).
 446  */
 447 int acpi_dev_get_property(struct acpi_device *adev, const char *name,
 448                           acpi_object_type type, const union acpi_object **obj)
 449 {
 450         return adev ? acpi_data_get_property(&adev->data, name, type, obj) : -EINVAL;
 451 }
 452 EXPORT_SYMBOL_GPL(acpi_dev_get_property);
 453
 454 static struct acpi_device_data *acpi_device_data_of_node(struct fwnode_handle *fwnode)
 455 {
 456         if (fwnode->type == FWNODE_ACPI) {
 457                 struct acpi_device *adev = to_acpi_device_node(fwnode);
 458                 return &adev->data;
 459         } else if (fwnode->type == FWNODE_ACPI_DATA) {
 460                 struct acpi_data_node *dn = to_acpi_data_node(fwnode);
 461                 return &dn->data;
 462         }
 463         return NULL;
 464 }
 465
 466 /**
 467  * acpi_node_prop_get - return an ACPI property with given name.
 468  * @fwnode: Firmware node to get the property from.
 469  * @propname: Name of the property.
 470  * @valptr: Location to store a pointer to the property value (if not %NULL).
 471  */
 472 int acpi_node_prop_get(struct fwnode_handle *fwnode, const char *propname,
 473                        void **valptr)
 474 {
 475         return acpi_data_get_property(acpi_device_data_of_node(fwnode),
 476                                       propname, ACPI_TYPE_ANY,
 477                                       (const union acpi_object **)valptr);
 478 }
 479
 480 /**
 481  * acpi_data_get_property_array - return an ACPI array property with given name
 482  * @adev: ACPI data object to get the property from
 483  * @name: Name of the property
 484  * @type: Expected type of array elements
 485  * @obj: Location to store a pointer to the property value (if not NULL)
 486  *
 487  * Look up an array property with @name and store a pointer to the resulting
 488  * ACPI object at the location pointed to by @obj if found.
 489  *
 490  * Callers must not attempt to free the returned objects.  Those objects will be
 491  * freed by the ACPI core automatically during the removal of @data.
 492  *
 493  * Return: %0 if array property (package) with @name has been found (success),
 494  *         %-EINVAL if the arguments are invalid,
 495  *         %-EINVAL if the property doesn't exist,
 496  *         %-EPROTO if the property is not a package or the type of its elements
 497  *           doesn't match @type.
 498  */
 499 static int acpi_data_get_property_array(struct acpi_device_data *data,
 500                                         const char *name,
 501                                         acpi_object_type type,
 502                                         const union acpi_object **obj)
 503 {
 504         const union acpi_object *prop;
 505         int ret, i;
 506
 507         ret = acpi_data_get_property(data, name, ACPI_TYPE_PACKAGE, &prop);
 508         if (ret)
 509                 return ret;
 510
 511         if (type != ACPI_TYPE_ANY) {
 512                 /* Check that all elements are of correct type. */
 513                 for (i = 0; i < prop->package.count; i++)
 514                         if (prop->package.elements[i].type != type)
 515                                 return -EPROTO;
 516         }
 517         if (obj)
 518                 *obj = prop;
 519
 520         return 0;
 521 }
 522
 523 /**
 524  * __acpi_node_get_property_reference - returns handle to the referenced object
 525  * @fwnode: Firmware node to get the property from
 526  * @propname: Name of the property
 527  * @index: Index of the reference to return
 528  * @num_args: Maximum number of arguments after each reference
 529  * @args: Location to store the returned reference with optional arguments
 530  *
 531  * Find property with @name, verifify that it is a package containing at least
 532  * one object reference and if so, store the ACPI device object pointer to the
 533  * target object in @args->adev.  If the reference includes arguments, store
 534  * them in the @args->args[] array.
 535  *
 536  * If there's more than one reference in the property value package, @index is
 537  * used to select the one to return.
 538  *
 539  * It is possible to leave holes in the property value set like in the
 540  * example below:
 541  *
 542  * Package () {
 543  *     "cs-gpios",
 544  *     Package () {
 545  *        ^GPIO, 19, 0, 0,
 546  *        ^GPIO, 20, 0, 0,
 547  *        0,
 548  *        ^GPIO, 21, 0, 0,
 549  *     }
 550  * }
 551  *
 552  * Calling this function with index %2 return %-ENOENT and with index %3
 553  * returns the last entry. If the property does not contain any more values
 554  * %-ENODATA is returned. The NULL entry must be single integer and
 555  * preferably contain value %0.
 556  *
 557  * Return: %0 on success, negative error code on failure.
 558  */
 559 int __acpi_node_get_property_reference(struct fwnode_handle *fwnode,
 560         const char *propname, size_t index, size_t num_args,
 561         struct acpi_reference_args *args)
 562 {
 563         const union acpi_object *element, *end;
 564         const union acpi_object *obj;
 565         struct acpi_device_data *data;
 566         struct acpi_device *device;
 567         int ret, idx = 0;
 568
 569         data = acpi_device_data_of_node(fwnode);
 570         if (!data)
 571                 return -EINVAL;
 572
 573         ret = acpi_data_get_property(data, propname, ACPI_TYPE_ANY, &obj);
 574         if (ret)
 575                 return ret;
 576
 577         /*
 578          * The simplest case is when the value is a single reference.  Just
 579          * return that reference then.
 580          */
 581         if (obj->type == ACPI_TYPE_LOCAL_REFERENCE) {
 582                 if (index)
 583                         return -EINVAL;
 584
 585                 ret = acpi_bus_get_device(obj->reference.handle, &device);
 586                 if (ret)
 587                         return ret;
 588
 589                 args->adev = device;
 590                 args->nargs = 0;
 591                 return 0;
 592         }
 593
 594         /*
 595          * If it is not a single reference, then it is a package of
 596          * references followed by number of ints as follows:
 597          *
 598          *  Package () { REF, INT, REF, INT, INT }
 599          *
 600          * The index argument is then used to determine which reference
 601          * the caller wants (along with the arguments).
 602          */
 603         if (obj->type != ACPI_TYPE_PACKAGE || index >= obj->package.count)
 604                 return -EPROTO;
 605
 606         element = obj->package.elements;
 607         end = element + obj->package.count;
 608
 609         while (element < end) {
 610                 u32 nargs, i;
 611
 612                 if (element->type == ACPI_TYPE_LOCAL_REFERENCE) {
 613                         ret = acpi_bus_get_device(element->reference.handle,
 614                                                   &device);
 615                         if (ret)
 616                                 return -ENODEV;
 617
 618                         nargs = 0;
 619                         element++;
 620
 621                         /* assume following integer elements are all args */
 622                         for (i = 0; element + i < end && i < num_args; i++) {
 623                                 int type = element[i].type;
 624
 625                                 if (type == ACPI_TYPE_INTEGER)
 626                                         nargs++;
 627                                 else if (type == ACPI_TYPE_LOCAL_REFERENCE)
 628                                         break;
 629                                 else
 630                                         return -EPROTO;
 631                         }
 632
 633                         if (nargs > MAX_ACPI_REFERENCE_ARGS)
 634                                 return -EPROTO;
 635
 636                         if (idx == index) {
 637                                 args->adev = device;
 638                                 args->nargs = nargs;
 639                                 for (i = 0; i < nargs; i++)
 640                                         args->args[i] = element[i].integer.value;
 641
 642                                 return 0;
 643                         }
 644
 645                         element += nargs;
 646                 } else if (element->type == ACPI_TYPE_INTEGER) {
 647                         if (idx == index)
 648                                 return -ENOENT;
 649                         element++;
 650                 } else {
 651                         return -EPROTO;
 652                 }
 653
 654                 idx++;
 655         }
 656
 657         return -ENODATA;
 658 }
 659 EXPORT_SYMBOL_GPL(__acpi_node_get_property_reference);
 660
 661 static int acpi_data_prop_read_single(struct acpi_device_data *data,
 662                                       const char *propname,
 663                                       enum dev_prop_type proptype, void *val)
 664 {
 665         const union acpi_object *obj;
 666         int ret;
 667
 668         if (!val)
 669                 return -EINVAL;
 670
 671         if (proptype >= DEV_PROP_U8 && proptype <= DEV_PROP_U64) {
 672                 ret = acpi_data_get_property(data, propname, ACPI_TYPE_INTEGER, &obj);
 673                 if (ret)
 674                         return ret;
 675
 676                 switch (proptype) {
 677                 case DEV_PROP_U8:
 678                         if (obj->integer.value > U8_MAX)
 679                                 return -EOVERFLOW;
 680                         *(u8 *)val = obj->integer.value;
 681                         break;
 682                 case DEV_PROP_U16:
 683                         if (obj->integer.value > U16_MAX)
 684                                 return -EOVERFLOW;
 685                         *(u16 *)val = obj->integer.value;
 686                         break;
 687                 case DEV_PROP_U32:
 688                         if (obj->integer.value > U32_MAX)
 689                                 return -EOVERFLOW;
 690                         *(u32 *)val = obj->integer.value;
 691                         break;
 692                 default:
 693                         *(u64 *)val = obj->integer.value;
 694                         break;
 695                 }
 696         } else if (proptype == DEV_PROP_STRING) {
 697                 ret = acpi_data_get_property(data, propname, ACPI_TYPE_STRING, &obj);
 698                 if (ret)
 699                         return ret;
 700
 701                 *(char **)val = obj->string.pointer;
 702         } else {
 703                 ret = -EINVAL;
 704         }
 705         return ret;
 706 }
 707
 708 int acpi_dev_prop_read_single(struct acpi_device *adev, const char *propname,
 709                               enum dev_prop_type proptype, void *val)
 710 {
 711         return adev ? acpi_data_prop_read_single(&adev->data, propname, proptype, val) : -EINVAL;
 712 }
 713
 714 static int acpi_copy_property_array_u8(const union acpi_object *items, u8 *val,
 715                                        size_t nval)
 716 {
 717         int i;
 718
 719         for (i = 0; i < nval; i++) {
 720                 if (items[i].type != ACPI_TYPE_INTEGER)
 721                         return -EPROTO;
 722                 if (items[i].integer.value > U8_MAX)
 723                         return -EOVERFLOW;
 724
 725                 val[i] = items[i].integer.value;
 726         }
 727         return 0;
 728 }
 729
 730 static int acpi_copy_property_array_u16(const union acpi_object *items,
 731                                         u16 *val, size_t nval)
 732 {
 733         int i;
 734
 735         for (i = 0; i < nval; i++) {
 736                 if (items[i].type != ACPI_TYPE_INTEGER)
 737                         return -EPROTO;
 738                 if (items[i].integer.value > U16_MAX)
 739                         return -EOVERFLOW;
 740
 741                 val[i] = items[i].integer.value;
 742         }
 743         return 0;
 744 }
 745
 746 static int acpi_copy_property_array_u32(const union acpi_object *items,
 747                                         u32 *val, size_t nval)
 748 {
 749         int i;
 750
 751         for (i = 0; i < nval; i++) {
 752                 if (items[i].type != ACPI_TYPE_INTEGER)
 753                         return -EPROTO;
 754                 if (items[i].integer.value > U32_MAX)
 755                         return -EOVERFLOW;
 756
 757                 val[i] = items[i].integer.value;
 758         }
 759         return 0;
 760 }
 761
 762 static int acpi_copy_property_array_u64(const union acpi_object *items,
 763                                         u64 *val, size_t nval)
 764 {
 765         int i;
 766
 767         for (i = 0; i < nval; i++) {
 768                 if (items[i].type != ACPI_TYPE_INTEGER)
 769                         return -EPROTO;
 770
 771                 val[i] = items[i].integer.value;
 772         }
 773         return 0;
 774 }
 775
 776 static int acpi_copy_property_array_string(const union acpi_object *items,
 777                                            char **val, size_t nval)
 778 {
 779         int i;
 780
 781         for (i = 0; i < nval; i++) {
 782                 if (items[i].type != ACPI_TYPE_STRING)
 783                         return -EPROTO;
 784
 785                 val[i] = items[i].string.pointer;
 786         }
 787         return 0;
 788 }
 789
 790 static int acpi_data_prop_read(struct acpi_device_data *data,
 791                                const char *propname,
 792                                enum dev_prop_type proptype,
 793                                void *val, size_t nval)
 794 {
 795         const union acpi_object *obj;
 796         const union acpi_object *items;
 797         int ret;
 798
 799         if (val && nval == 1) {
 800                 ret = acpi_data_prop_read_single(data, propname, proptype, val);
 801                 if (!ret)
 802                         return ret;
 803         }
 804
 805         ret = acpi_data_get_property_array(data, propname, ACPI_TYPE_ANY, &obj);
 806         if (ret)
 807                 return ret;
 808
 809         if (!val)
 810                 return obj->package.count;
 811
 812         if (nval > obj->package.count)
 813                 return -EOVERFLOW;
 814         else if (nval <= 0)
 815                 return -EINVAL;
 816
 817         items = obj->package.elements;
 818
 819         switch (proptype) {
 820         case DEV_PROP_U8:
 821                 ret = acpi_copy_property_array_u8(items, (u8 *)val, nval);
 822                 break;
 823         case DEV_PROP_U16:
 824                 ret = acpi_copy_property_array_u16(items, (u16 *)val, nval);
 825                 break;
 826         case DEV_PROP_U32:
 827                 ret = acpi_copy_property_array_u32(items, (u32 *)val, nval);
 828                 break;
 829         case DEV_PROP_U64:
 830                 ret = acpi_copy_property_array_u64(items, (u64 *)val, nval);
 831                 break;
 832         case DEV_PROP_STRING:
 833                 ret = acpi_copy_property_array_string(items, (char **)val, nval);
 834                 break;
 835         default:
 836                 ret = -EINVAL;
 837                 break;
 838         }
 839         return ret;
 840 }
 841
 842 int acpi_dev_prop_read(struct acpi_device *adev, const char *propname,
 843                        enum dev_prop_type proptype, void *val, size_t nval)
 844 {
 845         return adev ? acpi_data_prop_read(&adev->data, propname, proptype, val, nval) : -EINVAL;
 846 }
 847
 848 /**
 849  * acpi_node_prop_read - retrieve the value of an ACPI property with given name.
 850  * @fwnode: Firmware node to get the property from.
 851  * @propname: Name of the property.
 852  * @proptype: Expected property type.
 853  * @val: Location to store the property value (if not %NULL).
 854  * @nval: Size of the array pointed to by @val.
 855  *
 856  * If @val is %NULL, return the number of array elements comprising the value
 857  * of the property.  Otherwise, read at most @nval values to the array at the
 858  * location pointed to by @val.
 859  */
 860 int acpi_node_prop_read(struct fwnode_handle *fwnode,  const char *propname,
 861                         enum dev_prop_type proptype, void *val, size_t nval)
 862 {
 863         return acpi_data_prop_read(acpi_device_data_of_node(fwnode),
 864                                    propname, proptype, val, nval);
 865 }
 866
 867 /**
 868  * acpi_get_next_subnode - Return the next child node handle for a device.
 869  * @dev: Device to find the next child node for.
 870  * @child: Handle to one of the device's child nodes or a null handle.
 871  */
 872 struct fwnode_handle *acpi_get_next_subnode(struct device *dev,
 873                                             struct fwnode_handle *child)
 874 {
 875         struct acpi_device *adev = ACPI_COMPANION(dev);
 876         struct list_head *head, *next;
 877
 878         if (!adev)
 879                 return NULL;
 880
 881         if (!child || child->type == FWNODE_ACPI) {
 882                 head = &adev->children;
 883                 if (list_empty(head))
 884                         goto nondev;
 885
 886                 if (child) {
 887                         adev = to_acpi_device_node(child);
 888                         next = adev->node.next;
 889                         if (next == head) {
 890                                 child = NULL;
 891                                 adev = ACPI_COMPANION(dev);
 892                                 goto nondev;
 893                         }
 894                         adev = list_entry(next, struct acpi_device, node);
 895                 } else {
 896                         adev = list_first_entry(head, struct acpi_device, node);
 897                 }
 898                 return acpi_fwnode_handle(adev);
 899         }
 900
 901  nondev:
 902         if (!child || child->type == FWNODE_ACPI_DATA) {
 903                 struct acpi_data_node *dn;
 904
 905                 head = &adev->data.subnodes;
 906                 if (list_empty(head))
 907                         return NULL;
 908
 909                 if (child) {
 910                         dn = to_acpi_data_node(child);
 911                         next = dn->sibling.next;
 912                         if (next == head)
 913                                 return NULL;
 914
 915                         dn = list_entry(next, struct acpi_data_node, sibling);
 916                 } else {
 917                         dn = list_first_entry(head, struct acpi_data_node, sibling);
 918                 }
 919                 return &dn->fwnode;
 920         }
 921         return NULL;
 922 }