uboot/drivers/core/of_access.c
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   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * Originally from Linux v4.9
   4 * Paul Mackerras       August 1996.
   5 * Copyright (C) 1996-2005 Paul Mackerras.
   6 *
   7 * Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
   8 *   {engebret|bergner}@us.ibm.com
   9 *
  10 * Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net
  11 *
  12 * Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell and
  13 * Grant Likely.
  14 *
  15 * Modified for U-Boot
  16 * Copyright (c) 2017 Google, Inc
  17 *
  18 * This file follows drivers/of/base.c with functions in the same order as the
  19 * Linux version.
  20 */
  21
  22#include <common.h>
  23#include <log.h>
  24#include <malloc.h>
  25#include <asm/global_data.h>
  26#include <linux/bug.h>
  27#include <linux/libfdt.h>
  28#include <dm/of_access.h>
  29#include <linux/ctype.h>
  30#include <linux/err.h>
  31#include <linux/ioport.h>
  32
  33DECLARE_GLOBAL_DATA_PTR;
  34
  35/* list of struct alias_prop aliases */
  36static LIST_HEAD(aliases_lookup);
  37
  38/* "/aliaes" node */
  39static struct device_node *of_aliases;
  40
  41/* "/chosen" node */
  42static struct device_node *of_chosen;
  43
  44/* node pointed to by the stdout-path alias */
  45static struct device_node *of_stdout;
  46
  47/* pointer to options given after the alias (separated by :) or NULL if none */
  48static const char *of_stdout_options;
  49
  50/**
  51 * struct alias_prop - Alias property in 'aliases' node
  52 *
  53 * The structure represents one alias property of 'aliases' node as
  54 * an entry in aliases_lookup list.
  55 *
  56 * @link:       List node to link the structure in aliases_lookup list
  57 * @alias:      Alias property name
  58 * @np:         Pointer to device_node that the alias stands for
  59 * @id:         Index value from end of alias name
  60 * @stem:       Alias string without the index
  61 */
  62struct alias_prop {
  63        struct list_head link;
  64        const char *alias;
  65        struct device_node *np;
  66        int id;
  67        char stem[0];
  68};
  69
  70int of_n_addr_cells(const struct device_node *np)
  71{
  72        const __be32 *ip;
  73
  74        do {
  75                if (np->parent)
  76                        np = np->parent;
  77                ip = of_get_property(np, "#address-cells", NULL);
  78                if (ip)
  79                        return be32_to_cpup(ip);
  80        } while (np->parent);
  81
  82        /* No #address-cells property for the root node */
  83        return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
  84}
  85
  86int of_n_size_cells(const struct device_node *np)
  87{
  88        const __be32 *ip;
  89
  90        do {
  91                if (np->parent)
  92                        np = np->parent;
  93                ip = of_get_property(np, "#size-cells", NULL);
  94                if (ip)
  95                        return be32_to_cpup(ip);
  96        } while (np->parent);
  97
  98        /* No #size-cells property for the root node */
  99        return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
 100}
 101
 102int of_simple_addr_cells(const struct device_node *np)
 103{
 104        const __be32 *ip;
 105
 106        ip = of_get_property(np, "#address-cells", NULL);
 107        if (ip)
 108                return be32_to_cpup(ip);
 109
 110        /* Return a default of 2 to match fdt_address_cells()*/
 111        return 2;
 112}
 113
 114int of_simple_size_cells(const struct device_node *np)
 115{
 116        const __be32 *ip;
 117
 118        ip = of_get_property(np, "#size-cells", NULL);
 119        if (ip)
 120                return be32_to_cpup(ip);
 121
 122        /* Return a default of 2 to match fdt_size_cells()*/
 123        return 2;
 124}
 125
 126struct property *of_find_property(const struct device_node *np,
 127                                  const char *name, int *lenp)
 128{
 129        struct property *pp;
 130
 131        if (!np)
 132                return NULL;
 133
 134        for (pp = np->properties; pp; pp = pp->next) {
 135                if (strcmp(pp->name, name) == 0) {
 136                        if (lenp)
 137                                *lenp = pp->length;
 138                        break;
 139                }
 140        }
 141        if (!pp && lenp)
 142                *lenp = -FDT_ERR_NOTFOUND;
 143
 144        return pp;
 145}
 146
 147struct device_node *of_find_all_nodes(struct device_node *prev)
 148{
 149        struct device_node *np;
 150
 151        if (!prev) {
 152                np = gd->of_root;
 153        } else if (prev->child) {
 154                np = prev->child;
 155        } else {
 156                /*
 157                 * Walk back up looking for a sibling, or the end of the
 158                 * structure
 159                 */
 160                np = prev;
 161                while (np->parent && !np->sibling)
 162                        np = np->parent;
 163                np = np->sibling; /* Might be null at the end of the tree */
 164        }
 165
 166        return np;
 167}
 168
 169const void *of_get_property(const struct device_node *np, const char *name,
 170                            int *lenp)
 171{
 172        struct property *pp = of_find_property(np, name, lenp);
 173
 174        return pp ? pp->value : NULL;
 175}
 176
 177const struct property *of_get_first_property(const struct device_node *np)
 178{
 179        if (!np)
 180                return NULL;
 181
 182        return  np->properties;
 183}
 184
 185const struct property *of_get_next_property(const struct device_node *np,
 186                                            const struct property *property)
 187{
 188        if (!np)
 189                return NULL;
 190
 191        return property->next;
 192}
 193
 194const void *of_get_property_by_prop(const struct device_node *np,
 195                                    const struct property *property,
 196                                    const char **name,
 197                                    int *lenp)
 198{
 199        if (!np || !property)
 200                return NULL;
 201        if (name)
 202                *name = property->name;
 203        if (lenp)
 204                *lenp = property->length;
 205
 206        return property->value;
 207}
 208
 209static const char *of_prop_next_string(struct property *prop, const char *cur)
 210{
 211        const void *curv = cur;
 212
 213        if (!prop)
 214                return NULL;
 215
 216        if (!cur)
 217                return prop->value;
 218
 219        curv += strlen(cur) + 1;
 220        if (curv >= prop->value + prop->length)
 221                return NULL;
 222
 223        return curv;
 224}
 225
 226int of_device_is_compatible(const struct device_node *device,
 227                            const char *compat, const char *type,
 228                            const char *name)
 229{
 230        struct property *prop;
 231        const char *cp;
 232        int index = 0, score = 0;
 233
 234        /* Compatible match has highest priority */
 235        if (compat && compat[0]) {
 236                prop = of_find_property(device, "compatible", NULL);
 237                for (cp = of_prop_next_string(prop, NULL); cp;
 238                     cp = of_prop_next_string(prop, cp), index++) {
 239                        if (of_compat_cmp(cp, compat, strlen(compat)) == 0) {
 240                                score = INT_MAX/2 - (index << 2);
 241                                break;
 242                        }
 243                }
 244                if (!score)
 245                        return 0;
 246        }
 247
 248        /* Matching type is better than matching name */
 249        if (type && type[0]) {
 250                if (!device->type || of_node_cmp(type, device->type))
 251                        return 0;
 252                score += 2;
 253        }
 254
 255        /* Matching name is a bit better than not */
 256        if (name && name[0]) {
 257                if (!device->name || of_node_cmp(name, device->name))
 258                        return 0;
 259                score++;
 260        }
 261
 262        return score;
 263}
 264
 265bool of_device_is_available(const struct device_node *device)
 266{
 267        const char *status;
 268        int statlen;
 269
 270        if (!device)
 271                return false;
 272
 273        status = of_get_property(device, "status", &statlen);
 274        if (status == NULL)
 275                return true;
 276
 277        if (statlen > 0) {
 278                if (!strcmp(status, "okay"))
 279                        return true;
 280        }
 281
 282        return false;
 283}
 284
 285struct device_node *of_get_parent(const struct device_node *node)
 286{
 287        const struct device_node *np;
 288
 289        if (!node)
 290                return NULL;
 291
 292        np = of_node_get(node->parent);
 293
 294        return (struct device_node *)np;
 295}
 296
 297static struct device_node *__of_get_next_child(const struct device_node *node,
 298                                               struct device_node *prev)
 299{
 300        struct device_node *next;
 301
 302        if (!node)
 303                return NULL;
 304
 305        next = prev ? prev->sibling : node->child;
 306        /*
 307         * coverity[dead_error_line : FALSE]
 308         * Dead code here since our current implementation of of_node_get()
 309         * always returns NULL (Coverity CID 163245). But we leave it as is
 310         * since we may want to implement get/put later.
 311         */
 312        for (; next; next = next->sibling)
 313                if (of_node_get(next))
 314                        break;
 315        of_node_put(prev);
 316        return next;
 317}
 318
 319#define __for_each_child_of_node(parent, child) \
 320        for (child = __of_get_next_child(parent, NULL); child != NULL; \
 321             child = __of_get_next_child(parent, child))
 322
 323static struct device_node *__of_find_node_by_path(struct device_node *parent,
 324                                                  const char *path)
 325{
 326        struct device_node *child;
 327        int len;
 328
 329        len = strcspn(path, "/:");
 330        if (!len)
 331                return NULL;
 332
 333        __for_each_child_of_node(parent, child) {
 334                const char *name = strrchr(child->full_name, '/');
 335
 336                name++;
 337                if (strncmp(path, name, len) == 0 && (strlen(name) == len))
 338                        return child;
 339        }
 340        return NULL;
 341}
 342
 343#define for_each_property_of_node(dn, pp) \
 344        for (pp = dn->properties; pp != NULL; pp = pp->next)
 345
 346struct device_node *of_find_node_opts_by_path(struct device_node *root,
 347                                              const char *path,
 348                                              const char **opts)
 349{
 350        struct device_node *np = NULL;
 351        struct property *pp;
 352        const char *separator = strchr(path, ':');
 353
 354        if (!root)
 355                root = gd->of_root;
 356        if (opts)
 357                *opts = separator ? separator + 1 : NULL;
 358
 359        if (strcmp(path, "/") == 0)
 360                return of_node_get(root);
 361
 362        /* The path could begin with an alias */
 363        if (*path != '/') {
 364                int len;
 365                const char *p = separator;
 366
 367                /* Only allow alias processing on the control FDT */
 368                if (root != gd->of_root)
 369                        return NULL;
 370                if (!p)
 371                        p = strchrnul(path, '/');
 372                len = p - path;
 373
 374                /* of_aliases must not be NULL */
 375                if (!of_aliases)
 376                        return NULL;
 377
 378                for_each_property_of_node(of_aliases, pp) {
 379                        if (strlen(pp->name) == len && !strncmp(pp->name, path,
 380                                                                len)) {
 381                                np = of_find_node_by_path(pp->value);
 382                                break;
 383                        }
 384                }
 385                if (!np)
 386                        return NULL;
 387                path = p;
 388        }
 389
 390        /* Step down the tree matching path components */
 391        if (!np)
 392                np = of_node_get(root);
 393        while (np && *path == '/') {
 394                struct device_node *tmp = np;
 395
 396                path++; /* Increment past '/' delimiter */
 397                np = __of_find_node_by_path(np, path);
 398                of_node_put(tmp);
 399                path = strchrnul(path, '/');
 400                if (separator && separator < path)
 401                        break;
 402        }
 403
 404        return np;
 405}
 406
 407struct device_node *of_find_compatible_node(struct device_node *from,
 408                const char *type, const char *compatible)
 409{
 410        struct device_node *np;
 411
 412        for_each_of_allnodes_from(from, np)
 413                if (of_device_is_compatible(np, compatible, type, NULL) &&
 414                    of_node_get(np))
 415                        break;
 416        of_node_put(from);
 417
 418        return np;
 419}
 420
 421static int of_device_has_prop_value(const struct device_node *device,
 422                                    const char *propname, const void *propval,
 423                                    int proplen)
 424{
 425        struct property *prop = of_find_property(device, propname, NULL);
 426
 427        if (!prop || !prop->value || prop->length != proplen)
 428                return 0;
 429        return !memcmp(prop->value, propval, proplen);
 430}
 431
 432struct device_node *of_find_node_by_prop_value(struct device_node *from,
 433                                               const char *propname,
 434                                               const void *propval, int proplen)
 435{
 436        struct device_node *np;
 437
 438        for_each_of_allnodes_from(from, np) {
 439                if (of_device_has_prop_value(np, propname, propval, proplen) &&
 440                    of_node_get(np))
 441                        break;
 442        }
 443        of_node_put(from);
 444
 445        return np;
 446}
 447
 448struct device_node *of_find_node_by_phandle(struct device_node *root,
 449                                            phandle handle)
 450{
 451        struct device_node *np;
 452
 453        if (!handle)
 454                return NULL;
 455
 456        for_each_of_allnodes_from(root, np)
 457                if (np->phandle == handle)
 458                        break;
 459        (void)of_node_get(np);
 460
 461        return np;
 462}
 463
 464/**
 465 * of_find_property_value_of_size() - find property of given size
 466 *
 467 * Search for a property in a device node and validate the requested size.
 468 *
 469 * @np:         device node from which the property value is to be read.
 470 * @propname:   name of the property to be searched.
 471 * @len:        requested length of property value
 472 *
 473 * Return: the property value on success, -EINVAL if the property does not
 474 * exist and -EOVERFLOW if the property data isn't large enough.
 475 */
 476static void *of_find_property_value_of_size(const struct device_node *np,
 477                                            const char *propname, u32 len)
 478{
 479        struct property *prop = of_find_property(np, propname, NULL);
 480
 481        if (!prop)
 482                return ERR_PTR(-EINVAL);
 483        if (len > prop->length)
 484                return ERR_PTR(-EOVERFLOW);
 485
 486        return prop->value;
 487}
 488
 489int of_read_u8(const struct device_node *np, const char *propname, u8 *outp)
 490{
 491        const u8 *val;
 492
 493        debug("%s: %s: ", __func__, propname);
 494        if (!np)
 495                return -EINVAL;
 496        val = of_find_property_value_of_size(np, propname, sizeof(*outp));
 497        if (IS_ERR(val)) {
 498                debug("(not found)\n");
 499                return PTR_ERR(val);
 500        }
 501
 502        *outp = *val;
 503        debug("%#x (%d)\n", *outp, *outp);
 504
 505        return 0;
 506}
 507
 508int of_read_u16(const struct device_node *np, const char *propname, u16 *outp)
 509{
 510        const __be16 *val;
 511
 512        debug("%s: %s: ", __func__, propname);
 513        if (!np)
 514                return -EINVAL;
 515        val = of_find_property_value_of_size(np, propname, sizeof(*outp));
 516        if (IS_ERR(val)) {
 517                debug("(not found)\n");
 518                return PTR_ERR(val);
 519        }
 520
 521        *outp = be16_to_cpup(val);
 522        debug("%#x (%d)\n", *outp, *outp);
 523
 524        return 0;
 525}
 526
 527int of_read_u32(const struct device_node *np, const char *propname, u32 *outp)
 528{
 529        return of_read_u32_index(np, propname, 0, outp);
 530}
 531
 532int of_read_u32_array(const struct device_node *np, const char *propname,
 533                      u32 *out_values, size_t sz)
 534{
 535        const __be32 *val;
 536
 537        debug("%s: %s: ", __func__, propname);
 538        val = of_find_property_value_of_size(np, propname,
 539                                             sz * sizeof(*out_values));
 540
 541        if (IS_ERR(val))
 542                return PTR_ERR(val);
 543
 544        debug("size %zd\n", sz);
 545        while (sz--)
 546                *out_values++ = be32_to_cpup(val++);
 547
 548        return 0;
 549}
 550
 551int of_read_u32_index(const struct device_node *np, const char *propname,
 552                      int index, u32 *outp)
 553{
 554        const __be32 *val;
 555
 556        debug("%s: %s: ", __func__, propname);
 557        if (!np)
 558                return -EINVAL;
 559
 560        val = of_find_property_value_of_size(np, propname,
 561                                             sizeof(*outp) * (index + 1));
 562        if (IS_ERR(val)) {
 563                debug("(not found)\n");
 564                return PTR_ERR(val);
 565        }
 566
 567        *outp = be32_to_cpup(val + index);
 568        debug("%#x (%d)\n", *outp, *outp);
 569
 570        return 0;
 571}
 572
 573int of_read_u64(const struct device_node *np, const char *propname, u64 *outp)
 574{
 575        const __be64 *val;
 576
 577        debug("%s: %s: ", __func__, propname);
 578        if (!np)
 579                return -EINVAL;
 580        val = of_find_property_value_of_size(np, propname, sizeof(*outp));
 581        if (IS_ERR(val)) {
 582                debug("(not found)\n");
 583                return PTR_ERR(val);
 584        }
 585
 586        *outp = be64_to_cpup(val);
 587        debug("%#llx (%lld)\n", (unsigned long long)*outp,
 588              (unsigned long long)*outp);
 589
 590        return 0;
 591}
 592
 593int of_property_match_string(const struct device_node *np, const char *propname,
 594                             const char *string)
 595{
 596        const struct property *prop = of_find_property(np, propname, NULL);
 597        size_t l;
 598        int i;
 599        const char *p, *end;
 600
 601        if (!prop)
 602                return -EINVAL;
 603        if (!prop->value)
 604                return -ENODATA;
 605
 606        p = prop->value;
 607        end = p + prop->length;
 608
 609        for (i = 0; p < end; i++, p += l) {
 610                l = strnlen(p, end - p) + 1;
 611                if (p + l > end)
 612                        return -EILSEQ;
 613                debug("comparing %s with %s\n", string, p);
 614                if (strcmp(string, p) == 0)
 615                        return i; /* Found it; return index */
 616        }
 617        return -ENODATA;
 618}
 619
 620/**
 621 * of_property_read_string_helper() - Utility helper for parsing string properties
 622 * @np:         device node from which the property value is to be read.
 623 * @propname:   name of the property to be searched.
 624 * @out_strs:   output array of string pointers.
 625 * @sz:         number of array elements to read.
 626 * @skip:       Number of strings to skip over at beginning of list (cannot be
 627 *      negative)
 628 *
 629 * Don't call this function directly. It is a utility helper for the
 630 * of_property_read_string*() family of functions.
 631 */
 632int of_property_read_string_helper(const struct device_node *np,
 633                                   const char *propname, const char **out_strs,
 634                                   size_t sz, int skip)
 635{
 636        const struct property *prop = of_find_property(np, propname, NULL);
 637        int l = 0, i = 0;
 638        const char *p, *end;
 639
 640        if (!prop)
 641                return -EINVAL;
 642        if (!prop->value)
 643                return -ENODATA;
 644        p = prop->value;
 645        end = p + prop->length;
 646
 647        for (i = 0; p < end && (!out_strs || i < skip + sz); i++, p += l) {
 648                l = strnlen(p, end - p) + 1;
 649                if (p + l > end)
 650                        return -EILSEQ;
 651                if (out_strs && i >= skip)
 652                        *out_strs++ = p;
 653        }
 654        i -= skip;
 655        return i <= 0 ? -ENODATA : i;
 656}
 657
 658static int __of_parse_phandle_with_args(const struct device_node *np,
 659                                        const char *list_name,
 660                                        const char *cells_name,
 661                                        int cell_count, int index,
 662                                        struct of_phandle_args *out_args)
 663{
 664        const __be32 *list, *list_end;
 665        int rc = 0, cur_index = 0;
 666        uint32_t count;
 667        struct device_node *node = NULL;
 668        phandle phandle;
 669        int size;
 670
 671        /* Retrieve the phandle list property */
 672        list = of_get_property(np, list_name, &size);
 673        if (!list)
 674                return -ENOENT;
 675        list_end = list + size / sizeof(*list);
 676
 677        /* Loop over the phandles until all the requested entry is found */
 678        while (list < list_end) {
 679                rc = -EINVAL;
 680                count = 0;
 681
 682                /*
 683                 * If phandle is 0, then it is an empty entry with no
 684                 * arguments.  Skip forward to the next entry.
 685                 */
 686                phandle = be32_to_cpup(list++);
 687                if (phandle) {
 688                        /*
 689                         * Find the provider node and parse the #*-cells
 690                         * property to determine the argument length.
 691                         *
 692                         * This is not needed if the cell count is hard-coded
 693                         * (i.e. cells_name not set, but cell_count is set),
 694                         * except when we're going to return the found node
 695                         * below.
 696                         */
 697                        if (cells_name || cur_index == index) {
 698                                node = of_find_node_by_phandle(NULL, phandle);
 699                                if (!node) {
 700                                        debug("%s: could not find phandle\n",
 701                                              np->full_name);
 702                                        goto err;
 703                                }
 704                        }
 705
 706                        if (cells_name) {
 707                                if (of_read_u32(node, cells_name, &count)) {
 708                                        debug("%s: could not get %s for %s\n",
 709                                              np->full_name, cells_name,
 710                                              node->full_name);
 711                                        goto err;
 712                                }
 713                        } else {
 714                                count = cell_count;
 715                        }
 716
 717                        /*
 718                         * Make sure that the arguments actually fit in the
 719                         * remaining property data length
 720                         */
 721                        if (list + count > list_end) {
 722                                debug("%s: arguments longer than property\n",
 723                                      np->full_name);
 724                                goto err;
 725                        }
 726                }
 727
 728                /*
 729                 * All of the error cases above bail out of the loop, so at
 730                 * this point, the parsing is successful. If the requested
 731                 * index matches, then fill the out_args structure and return,
 732                 * or return -ENOENT for an empty entry.
 733                 */
 734                rc = -ENOENT;
 735                if (cur_index == index) {
 736                        if (!phandle)
 737                                goto err;
 738
 739                        if (out_args) {
 740                                int i;
 741                                if (WARN_ON(count > OF_MAX_PHANDLE_ARGS))
 742                                        count = OF_MAX_PHANDLE_ARGS;
 743                                out_args->np = node;
 744                                out_args->args_count = count;
 745                                for (i = 0; i < count; i++)
 746                                        out_args->args[i] =
 747                                                        be32_to_cpup(list++);
 748                        } else {
 749                                of_node_put(node);
 750                        }
 751
 752                        /* Found it! return success */
 753                        return 0;
 754                }
 755
 756                of_node_put(node);
 757                node = NULL;
 758                list += count;
 759                cur_index++;
 760        }
 761
 762        /*
 763         * Unlock node before returning result; will be one of:
 764         * -ENOENT : index is for empty phandle
 765         * -EINVAL : parsing error on data
 766         * [1..n]  : Number of phandle (count mode; when index = -1)
 767         */
 768        rc = index < 0 ? cur_index : -ENOENT;
 769 err:
 770        if (node)
 771                of_node_put(node);
 772        return rc;
 773}
 774
 775struct device_node *of_parse_phandle(const struct device_node *np,
 776                                     const char *phandle_name, int index)
 777{
 778        struct of_phandle_args args;
 779
 780        if (index < 0)
 781                return NULL;
 782
 783        if (__of_parse_phandle_with_args(np, phandle_name, NULL, 0, index,
 784                                         &args))
 785                return NULL;
 786
 787        return args.np;
 788}
 789
 790int of_parse_phandle_with_args(const struct device_node *np,
 791                               const char *list_name, const char *cells_name,
 792                               int cell_count, int index,
 793                               struct of_phandle_args *out_args)
 794{
 795        if (index < 0)
 796                return -EINVAL;
 797
 798        return __of_parse_phandle_with_args(np, list_name, cells_name,
 799                                            cell_count, index, out_args);
 800}
 801
 802int of_count_phandle_with_args(const struct device_node *np,
 803                               const char *list_name, const char *cells_name,
 804                               int cell_count)
 805{
 806        return __of_parse_phandle_with_args(np, list_name, cells_name,
 807                                            cell_count, -1, NULL);
 808}
 809
 810static void of_alias_add(struct alias_prop *ap, struct device_node *np,
 811                         int id, const char *stem, int stem_len)
 812{
 813        ap->np = np;
 814        ap->id = id;
 815        strncpy(ap->stem, stem, stem_len);
 816        ap->stem[stem_len] = 0;
 817        list_add_tail(&ap->link, &aliases_lookup);
 818        debug("adding DT alias:%s: stem=%s id=%i node=%s\n",
 819              ap->alias, ap->stem, ap->id, of_node_full_name(np));
 820}
 821
 822int of_alias_scan(void)
 823{
 824        struct property *pp;
 825
 826        of_aliases = of_find_node_by_path("/aliases");
 827        of_chosen = of_find_node_by_path("/chosen");
 828        if (of_chosen == NULL)
 829                of_chosen = of_find_node_by_path("/chosen@0");
 830
 831        if (of_chosen) {
 832                const char *name;
 833
 834                name = of_get_property(of_chosen, "stdout-path", NULL);
 835                if (name)
 836                        of_stdout = of_find_node_opts_by_path(NULL, name,
 837                                                        &of_stdout_options);
 838        }
 839
 840        if (!of_aliases)
 841                return 0;
 842
 843        for_each_property_of_node(of_aliases, pp) {
 844                const char *start = pp->name;
 845                const char *end = start + strlen(start);
 846                struct device_node *np;
 847                struct alias_prop *ap;
 848                ulong id;
 849                int len;
 850
 851                /* Skip those we do not want to proceed */
 852                if (!strcmp(pp->name, "name") ||
 853                    !strcmp(pp->name, "phandle") ||
 854                    !strcmp(pp->name, "linux,phandle"))
 855                        continue;
 856
 857                np = of_find_node_by_path(pp->value);
 858                if (!np)
 859                        continue;
 860
 861                /*
 862                 * walk the alias backwards to extract the id and work out
 863                 * the 'stem' string
 864                 */
 865                while (isdigit(*(end-1)) && end > start)
 866                        end--;
 867                len = end - start;
 868
 869                if (strict_strtoul(end, 10, &id) < 0)
 870                        continue;
 871
 872                /* Allocate an alias_prop with enough space for the stem */
 873                ap = malloc(sizeof(*ap) + len + 1);
 874                if (!ap)
 875                        return -ENOMEM;
 876                memset(ap, 0, sizeof(*ap) + len + 1);
 877                ap->alias = start;
 878                of_alias_add(ap, np, id, start, len);
 879        }
 880
 881        return 0;
 882}
 883
 884int of_alias_get_id(const struct device_node *np, const char *stem)
 885{
 886        struct alias_prop *app;
 887        int id = -ENODEV;
 888
 889        mutex_lock(&of_mutex);
 890        list_for_each_entry(app, &aliases_lookup, link) {
 891                if (strcmp(app->stem, stem) != 0)
 892                        continue;
 893
 894                if (np == app->np) {
 895                        id = app->id;
 896                        break;
 897                }
 898        }
 899        mutex_unlock(&of_mutex);
 900
 901        return id;
 902}
 903
 904int of_alias_get_highest_id(const char *stem)
 905{
 906        struct alias_prop *app;
 907        int id = -1;
 908
 909        mutex_lock(&of_mutex);
 910        list_for_each_entry(app, &aliases_lookup, link) {
 911                if (strcmp(app->stem, stem) != 0)
 912                        continue;
 913
 914                if (app->id > id)
 915                        id = app->id;
 916        }
 917        mutex_unlock(&of_mutex);
 918
 919        return id;
 920}
 921
 922struct device_node *of_get_stdout(void)
 923{
 924        return of_stdout;
 925}
 926
 927int of_write_prop(struct device_node *np, const char *propname, int len,
 928                  const void *value)
 929{
 930        struct property *pp;
 931        struct property *pp_last = NULL;
 932        struct property *new;
 933
 934        if (!np)
 935                return -EINVAL;
 936
 937        for (pp = np->properties; pp; pp = pp->next) {
 938                if (strcmp(pp->name, propname) == 0) {
 939                        /* Property exists -> change value */
 940                        pp->value = (void *)value;
 941                        pp->length = len;
 942                        return 0;
 943                }
 944                pp_last = pp;
 945        }
 946
 947        /* Property does not exist -> append new property */
 948        new = malloc(sizeof(struct property));
 949        if (!new)
 950                return -ENOMEM;
 951
 952        new->name = strdup(propname);
 953        if (!new->name) {
 954                free(new);
 955                return -ENOMEM;
 956        }
 957
 958        new->value = (void *)value;
 959        new->length = len;
 960        new->next = NULL;
 961
 962        if (pp_last)
 963                pp_last->next = new;
 964        else
 965                np->properties = new;
 966
 967        return 0;
 968}
 969
 970int of_add_subnode(struct device_node *parent, const char *name, int len,
 971                   struct device_node **childp)
 972{
 973        struct device_node *child, *new, *last_sibling = NULL;
 974        char *new_name, *full_name;
 975        int parent_fnl;
 976
 977        if (len == -1)
 978                len = strlen(name);
 979        __for_each_child_of_node(parent, child) {
 980                /*
 981                 * make sure we don't use a child called "trevor" when we are
 982                 * searching for "trev".
 983                 */
 984                if (!strncmp(child->name, name, len) && strlen(name) == len) {
 985                        *childp = child;
 986                        return -EEXIST;
 987                }
 988                last_sibling = child;
 989        }
 990
 991        /* Subnode does not exist -> append new subnode */
 992        new = calloc(1, sizeof(struct device_node));
 993        if (!new)
 994                return -ENOMEM;
 995
 996        new_name = memdup(name, len + 1);
 997        if (!new_name) {
 998                free(new);
 999                return -ENOMEM;
1000        }
1001        new_name[len] = '\0';
1002
1003        /*
1004         * if the parent is the root node (named "") we don't need to prepend
1005         * its full path
1006         */
1007        parent_fnl = *parent->name ? strlen(parent->full_name) : 0;
1008        full_name = calloc(1, parent_fnl + 1 + len + 1);
1009        if (!full_name) {
1010                free(new_name);
1011                free(new);
1012                return -ENOMEM;
1013        }
1014        new->name = new_name;   /* assign to constant pointer */
1015
1016        strcpy(full_name, parent->full_name); /* "" for root node */
1017        full_name[parent_fnl] = '/';
1018        strlcpy(&full_name[parent_fnl + 1], name, len + 1);
1019        new->full_name = full_name;
1020
1021        /* Add as last sibling of the parent */
1022        if (last_sibling)
1023                last_sibling->sibling = new;
1024        if (!parent->child)
1025                parent->child = new;
1026        new->parent = parent;
1027
1028        *childp = new;
1029
1030        return 0;
1031}
1032