drivers/core/of_access.c

   1 /*
   2  * Originally from Linux v4.9
   3  * Paul Mackerras       August 1996.
   4  * Copyright (C) 1996-2005 Paul Mackerras.
   5  *
   6  * Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
   7  *   {engebret|bergner}@us.ibm.com
   8  *
   9  * Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net
  10  *
  11  * Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell and
  12  * Grant Likely.
  13  *
  14  * Modified for U-Boot
  15  * Copyright (c) 2017 Google, Inc
  16  *
  17  * This file follows drivers/of/base.c with functions in the same order as the
  18  * Linux version.
  19  *
  20  * SPDX-License-Identifier:     GPL-2.0+
  21  */
  22
  23 #include <common.h>
  24 #include <libfdt.h>
  25 #include <dm/of_access.h>
  26 #include <linux/ctype.h>
  27 #include <linux/err.h>
  28 #include <linux/ioport.h>
  29
  30 DECLARE_GLOBAL_DATA_PTR;
  31
  32 /* list of struct alias_prop aliases */
  33 LIST_HEAD(aliases_lookup);
  34
  35 /* "/aliaes" node */
  36 static struct device_node *of_aliases;
  37
  38 /* "/chosen" node */
  39 static struct device_node *of_chosen;
  40
  41 /* node pointed to by the stdout-path alias */
  42 static struct device_node *of_stdout;
  43
  44 /* pointer to options given after the alias (separated by :) or NULL if none */
  45 static const char *of_stdout_options;
  46
  47 /**
  48  * struct alias_prop - Alias property in 'aliases' node
  49  *
  50  * The structure represents one alias property of 'aliases' node as
  51  * an entry in aliases_lookup list.
  52  *
  53  * @link:       List node to link the structure in aliases_lookup list
  54  * @alias:      Alias property name
  55  * @np:         Pointer to device_node that the alias stands for
  56  * @id:         Index value from end of alias name
  57  * @stem:       Alias string without the index
  58  */
  59 struct alias_prop {
  60         struct list_head link;
  61         const char *alias;
  62         struct device_node *np;
  63         int id;
  64         char stem[0];
  65 };
  66
  67 int of_n_addr_cells(const struct device_node *np)
  68 {
  69         const __be32 *ip;
  70
  71         do {
  72                 if (np->parent)
  73                         np = np->parent;
  74                 ip = of_get_property(np, "#address-cells", NULL);
  75                 if (ip)
  76                         return be32_to_cpup(ip);
  77         } while (np->parent);
  78
  79         /* No #address-cells property for the root node */
  80         return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
  81 }
  82
  83 int of_n_size_cells(const struct device_node *np)
  84 {
  85         const __be32 *ip;
  86
  87         do {
  88                 if (np->parent)
  89                         np = np->parent;
  90                 ip = of_get_property(np, "#size-cells", NULL);
  91                 if (ip)
  92                         return be32_to_cpup(ip);
  93         } while (np->parent);
  94
  95         /* No #size-cells property for the root node */
  96         return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
  97 }
  98
  99 int of_simple_addr_cells(const struct device_node *np)
 100 {
 101         const __be32 *ip;
 102
 103         ip = of_get_property(np, "#address-cells", NULL);
 104         if (ip)
 105                 return be32_to_cpup(ip);
 106
 107         /* Return a default of 2 to match fdt_address_cells()*/
 108         return 2;
 109 }
 110
 111 int of_simple_size_cells(const struct device_node *np)
 112 {
 113         const __be32 *ip;
 114
 115         ip = of_get_property(np, "#size-cells", NULL);
 116         if (ip)
 117                 return be32_to_cpup(ip);
 118
 119         /* Return a default of 2 to match fdt_size_cells()*/
 120         return 2;
 121 }
 122
 123 struct property *of_find_property(const struct device_node *np,
 124                                   const char *name, int *lenp)
 125 {
 126         struct property *pp;
 127
 128         if (!np)
 129                 return NULL;
 130
 131         for (pp = np->properties; pp; pp = pp->next) {
 132                 if (strcmp(pp->name, name) == 0) {
 133                         if (lenp)
 134                                 *lenp = pp->length;
 135                         break;
 136                 }
 137         }
 138         if (!pp && lenp)
 139                 *lenp = -FDT_ERR_NOTFOUND;
 140
 141         return pp;
 142 }
 143
 144 struct device_node *of_find_all_nodes(struct device_node *prev)
 145 {
 146         struct device_node *np;
 147
 148         if (!prev) {
 149                 np = gd->of_root;
 150         } else if (prev->child) {
 151                 np = prev->child;
 152         } else {
 153                 /*
 154                  * Walk back up looking for a sibling, or the end of the
 155                  * structure
 156                  */
 157                 np = prev;
 158                 while (np->parent && !np->sibling)
 159                         np = np->parent;
 160                 np = np->sibling; /* Might be null at the end of the tree */
 161         }
 162
 163         return np;
 164 }
 165
 166 const void *of_get_property(const struct device_node *np, const char *name,
 167                             int *lenp)
 168 {
 169         struct property *pp = of_find_property(np, name, lenp);
 170
 171         return pp ? pp->value : NULL;
 172 }
 173
 174 static const char *of_prop_next_string(struct property *prop, const char *cur)
 175 {
 176         const void *curv = cur;
 177
 178         if (!prop)
 179                 return NULL;
 180
 181         if (!cur)
 182                 return prop->value;
 183
 184         curv += strlen(cur) + 1;
 185         if (curv >= prop->value + prop->length)
 186                 return NULL;
 187
 188         return curv;
 189 }
 190
 191 int of_device_is_compatible(const struct device_node *device,
 192                             const char *compat, const char *type,
 193                             const char *name)
 194 {
 195         struct property *prop;
 196         const char *cp;
 197         int index = 0, score = 0;
 198
 199         /* Compatible match has highest priority */
 200         if (compat && compat[0]) {
 201                 prop = of_find_property(device, "compatible", NULL);
 202                 for (cp = of_prop_next_string(prop, NULL); cp;
 203                      cp = of_prop_next_string(prop, cp), index++) {
 204                         if (of_compat_cmp(cp, compat, strlen(compat)) == 0) {
 205                                 score = INT_MAX/2 - (index << 2);
 206                                 break;
 207                         }
 208                 }
 209                 if (!score)
 210                         return 0;
 211         }
 212
 213         /* Matching type is better than matching name */
 214         if (type && type[0]) {
 215                 if (!device->type || of_node_cmp(type, device->type))
 216                         return 0;
 217                 score += 2;
 218         }
 219
 220         /* Matching name is a bit better than not */
 221         if (name && name[0]) {
 222                 if (!device->name || of_node_cmp(name, device->name))
 223                         return 0;
 224                 score++;
 225         }
 226
 227         return score;
 228 }
 229
 230 bool of_device_is_available(const struct device_node *device)
 231 {
 232         const char *status;
 233         int statlen;
 234
 235         if (!device)
 236                 return false;
 237
 238         status = of_get_property(device, "status", &statlen);
 239         if (status == NULL)
 240                 return true;
 241
 242         if (statlen > 0) {
 243                 if (!strcmp(status, "okay"))
 244                         return true;
 245         }
 246
 247         return false;
 248 }
 249
 250 struct device_node *of_get_parent(const struct device_node *node)
 251 {
 252         const struct device_node *np;
 253
 254         if (!node)
 255                 return NULL;
 256
 257         np = of_node_get(node->parent);
 258
 259         return (struct device_node *)np;
 260 }
 261
 262 static struct device_node *__of_get_next_child(const struct device_node *node,
 263                                                struct device_node *prev)
 264 {
 265         struct device_node *next;
 266
 267         if (!node)
 268                 return NULL;
 269
 270         next = prev ? prev->sibling : node->child;
 271         /*
 272          * coverity[dead_error_line : FALSE]
 273          * Dead code here since our current implementation of of_node_get()
 274          * always returns NULL (Coverity CID 163245). But we leave it as is
 275          * since we may want to implement get/put later.
 276          */
 277         for (; next; next = next->sibling)
 278                 if (of_node_get(next))
 279                         break;
 280         of_node_put(prev);
 281         return next;
 282 }
 283
 284 #define __for_each_child_of_node(parent, child) \
 285         for (child = __of_get_next_child(parent, NULL); child != NULL; \
 286              child = __of_get_next_child(parent, child))
 287
 288 static struct device_node *__of_find_node_by_path(struct device_node *parent,
 289                                                   const char *path)
 290 {
 291         struct device_node *child;
 292         int len;
 293
 294         len = strcspn(path, "/:");
 295         if (!len)
 296                 return NULL;
 297
 298         __for_each_child_of_node(parent, child) {
 299                 const char *name = strrchr(child->full_name, '/');
 300
 301                 name++;
 302                 if (strncmp(path, name, len) == 0 && (strlen(name) == len))
 303                         return child;
 304         }
 305         return NULL;
 306 }
 307
 308 #define for_each_property_of_node(dn, pp) \
 309         for (pp = dn->properties; pp != NULL; pp = pp->next)
 310
 311 struct device_node *of_find_node_opts_by_path(const char *path,
 312                                               const char **opts)
 313 {
 314         struct device_node *np = NULL;
 315         struct property *pp;
 316         const char *separator = strchr(path, ':');
 317
 318         if (opts)
 319                 *opts = separator ? separator + 1 : NULL;
 320
 321         if (strcmp(path, "/") == 0)
 322                 return of_node_get(gd->of_root);
 323
 324         /* The path could begin with an alias */
 325         if (*path != '/') {
 326                 int len;
 327                 const char *p = separator;
 328
 329                 if (!p)
 330                         p = strchrnul(path, '/');
 331                 len = p - path;
 332
 333                 /* of_aliases must not be NULL */
 334                 if (!of_aliases)
 335                         return NULL;
 336
 337                 for_each_property_of_node(of_aliases, pp) {
 338                         if (strlen(pp->name) == len && !strncmp(pp->name, path,
 339                                                                 len)) {
 340                                 np = of_find_node_by_path(pp->value);
 341                                 break;
 342                         }
 343                 }
 344                 if (!np)
 345                         return NULL;
 346                 path = p;
 347         }
 348
 349         /* Step down the tree matching path components */
 350         if (!np)
 351                 np = of_node_get(gd->of_root);
 352         while (np && *path == '/') {
 353                 struct device_node *tmp = np;
 354
 355                 path++; /* Increment past '/' delimiter */
 356                 np = __of_find_node_by_path(np, path);
 357                 of_node_put(tmp);
 358                 path = strchrnul(path, '/');
 359                 if (separator && separator < path)
 360                         break;
 361         }
 362
 363         return np;
 364 }
 365
 366 struct device_node *of_find_compatible_node(struct device_node *from,
 367                 const char *type, const char *compatible)
 368 {
 369         struct device_node *np;
 370
 371         for_each_of_allnodes_from(from, np)
 372                 if (of_device_is_compatible(np, compatible, type, NULL) &&
 373                     of_node_get(np))
 374                         break;
 375         of_node_put(from);
 376
 377         return np;
 378 }
 379
 380 struct device_node *of_find_node_by_phandle(phandle handle)
 381 {
 382         struct device_node *np;
 383
 384         if (!handle)
 385                 return NULL;
 386
 387         for_each_of_allnodes(np)
 388                 if (np->phandle == handle)
 389                         break;
 390         (void)of_node_get(np);
 391
 392         return np;
 393 }
 394
 395 /**
 396  * of_find_property_value_of_size() - find property of given size
 397  *
 398  * Search for a property in a device node and validate the requested size.
 399  *
 400  * @np:         device node from which the property value is to be read.
 401  * @propname:   name of the property to be searched.
 402  * @len:        requested length of property value
 403  *
 404  * @return the property value on success, -EINVAL if the property does not
 405  * exist, -ENODATA if property does not have a value, and -EOVERFLOW if the
 406  * property data isn't large enough.
 407  */
 408 static void *of_find_property_value_of_size(const struct device_node *np,
 409                                             const char *propname, u32 len)
 410 {
 411         struct property *prop = of_find_property(np, propname, NULL);
 412
 413         if (!prop)
 414                 return ERR_PTR(-EINVAL);
 415         if (!prop->value)
 416                 return ERR_PTR(-ENODATA);
 417         if (len > prop->length)
 418                 return ERR_PTR(-EOVERFLOW);
 419
 420         return prop->value;
 421 }
 422
 423 int of_read_u32(const struct device_node *np, const char *propname, u32 *outp)
 424 {
 425         const __be32 *val;
 426
 427         debug("%s: %s: ", __func__, propname);
 428         if (!np)
 429                 return -EINVAL;
 430         val = of_find_property_value_of_size(np, propname, sizeof(*outp));
 431         if (IS_ERR(val)) {
 432                 debug("(not found)\n");
 433                 return PTR_ERR(val);
 434         }
 435
 436         *outp = be32_to_cpup(val);
 437         debug("%#x (%d)\n", *outp, *outp);
 438
 439         return 0;
 440 }
 441
 442 int of_read_u32_array(const struct device_node *np, const char *propname,
 443                       u32 *out_values, size_t sz)
 444 {
 445         const __be32 *val;
 446
 447         debug("%s: %s: ", __func__, propname);
 448         val = of_find_property_value_of_size(np, propname,
 449                                              sz * sizeof(*out_values));
 450
 451         if (IS_ERR(val))
 452                 return PTR_ERR(val);
 453
 454         debug("size %zd\n", sz);
 455         while (sz--)
 456                 *out_values++ = be32_to_cpup(val++);
 457
 458         return 0;
 459 }
 460
 461 int of_property_match_string(const struct device_node *np, const char *propname,
 462                              const char *string)
 463 {
 464         const struct property *prop = of_find_property(np, propname, NULL);
 465         size_t l;
 466         int i;
 467         const char *p, *end;
 468
 469         if (!prop)
 470                 return -EINVAL;
 471         if (!prop->value)
 472                 return -ENODATA;
 473
 474         p = prop->value;
 475         end = p + prop->length;
 476
 477         for (i = 0; p < end; i++, p += l) {
 478                 l = strnlen(p, end - p) + 1;
 479                 if (p + l > end)
 480                         return -EILSEQ;
 481                 debug("comparing %s with %s\n", string, p);
 482                 if (strcmp(string, p) == 0)
 483                         return i; /* Found it; return index */
 484         }
 485         return -ENODATA;
 486 }
 487
 488 /**
 489  * of_property_read_string_helper() - Utility helper for parsing string properties
 490  * @np:         device node from which the property value is to be read.
 491  * @propname:   name of the property to be searched.
 492  * @out_strs:   output array of string pointers.
 493  * @sz:         number of array elements to read.
 494  * @skip:       Number of strings to skip over at beginning of list.
 495  *
 496  * Don't call this function directly. It is a utility helper for the
 497  * of_property_read_string*() family of functions.
 498  */
 499 int of_property_read_string_helper(const struct device_node *np,
 500                                    const char *propname, const char **out_strs,
 501                                    size_t sz, int skip)
 502 {
 503         const struct property *prop = of_find_property(np, propname, NULL);
 504         int l = 0, i = 0;
 505         const char *p, *end;
 506
 507         if (!prop)
 508                 return -EINVAL;
 509         if (!prop->value)
 510                 return -ENODATA;
 511         p = prop->value;
 512         end = p + prop->length;
 513
 514         for (i = 0; p < end && (!out_strs || i < skip + sz); i++, p += l) {
 515                 l = strnlen(p, end - p) + 1;
 516                 if (p + l > end)
 517                         return -EILSEQ;
 518                 if (out_strs && i >= skip)
 519                         *out_strs++ = p;
 520         }
 521         i -= skip;
 522         return i <= 0 ? -ENODATA : i;
 523 }
 524
 525 static int __of_parse_phandle_with_args(const struct device_node *np,
 526                                         const char *list_name,
 527                                         const char *cells_name,
 528                                         int cell_count, int index,
 529                                         struct of_phandle_args *out_args)
 530 {
 531         const __be32 *list, *list_end;
 532         int rc = 0, cur_index = 0;
 533         uint32_t count = 0;
 534         struct device_node *node = NULL;
 535         phandle phandle;
 536         int size;
 537
 538         /* Retrieve the phandle list property */
 539         list = of_get_property(np, list_name, &size);
 540         if (!list)
 541                 return -ENOENT;
 542         list_end = list + size / sizeof(*list);
 543
 544         /* Loop over the phandles until all the requested entry is found */
 545         while (list < list_end) {
 546                 rc = -EINVAL;
 547                 count = 0;
 548
 549                 /*
 550                  * If phandle is 0, then it is an empty entry with no
 551                  * arguments.  Skip forward to the next entry.
 552                  */
 553                 phandle = be32_to_cpup(list++);
 554                 if (phandle) {
 555                         /*
 556                          * Find the provider node and parse the #*-cells
 557                          * property to determine the argument length.
 558                          *
 559                          * This is not needed if the cell count is hard-coded
 560                          * (i.e. cells_name not set, but cell_count is set),
 561                          * except when we're going to return the found node
 562                          * below.
 563                          */
 564                         if (cells_name || cur_index == index) {
 565                                 node = of_find_node_by_phandle(phandle);
 566                                 if (!node) {
 567                                         debug("%s: could not find phandle\n",
 568                                               np->full_name);
 569                                         goto err;
 570                                 }
 571                         }
 572
 573                         if (cells_name) {
 574                                 if (of_read_u32(node, cells_name, &count)) {
 575                                         debug("%s: could not get %s for %s\n",
 576                                               np->full_name, cells_name,
 577                                               node->full_name);
 578                                         goto err;
 579                                 }
 580                         } else {
 581                                 count = cell_count;
 582                         }
 583
 584                         /*
 585                          * Make sure that the arguments actually fit in the
 586                          * remaining property data length
 587                          */
 588                         if (list + count > list_end) {
 589                                 debug("%s: arguments longer than property\n",
 590                                       np->full_name);
 591                                 goto err;
 592                         }
 593                 }
 594
 595                 /*
 596                  * All of the error cases above bail out of the loop, so at
 597                  * this point, the parsing is successful. If the requested
 598                  * index matches, then fill the out_args structure and return,
 599                  * or return -ENOENT for an empty entry.
 600                  */
 601                 rc = -ENOENT;
 602                 if (cur_index == index) {
 603                         if (!phandle)
 604                                 goto err;
 605
 606                         if (out_args) {
 607                                 int i;
 608                                 if (WARN_ON(count > OF_MAX_PHANDLE_ARGS))
 609                                         count = OF_MAX_PHANDLE_ARGS;
 610                                 out_args->np = node;
 611                                 out_args->args_count = count;
 612                                 for (i = 0; i < count; i++)
 613                                         out_args->args[i] =
 614                                                         be32_to_cpup(list++);
 615                         } else {
 616                                 of_node_put(node);
 617                         }
 618
 619                         /* Found it! return success */
 620                         return 0;
 621                 }
 622
 623                 of_node_put(node);
 624                 node = NULL;
 625                 list += count;
 626                 cur_index++;
 627         }
 628
 629         /*
 630          * Unlock node before returning result; will be one of:
 631          * -ENOENT : index is for empty phandle
 632          * -EINVAL : parsing error on data
 633          * [1..n]  : Number of phandle (count mode; when index = -1)
 634          */
 635         rc = index < 0 ? cur_index : -ENOENT;
 636  err:
 637         if (node)
 638                 of_node_put(node);
 639         return rc;
 640 }
 641
 642 struct device_node *of_parse_phandle(const struct device_node *np,
 643                                      const char *phandle_name, int index)
 644 {
 645         struct of_phandle_args args;
 646
 647         if (index < 0)
 648                 return NULL;
 649
 650         if (__of_parse_phandle_with_args(np, phandle_name, NULL, 0, index,
 651                                          &args))
 652                 return NULL;
 653
 654         return args.np;
 655 }
 656
 657 int of_parse_phandle_with_args(const struct device_node *np,
 658                                const char *list_name, const char *cells_name,
 659                                int index, struct of_phandle_args *out_args)
 660 {
 661         if (index < 0)
 662                 return -EINVAL;
 663
 664         return __of_parse_phandle_with_args(np, list_name, cells_name, 0,
 665                                             index, out_args);
 666 }
 667
 668 int of_count_phandle_with_args(const struct device_node *np,
 669                                const char *list_name, const char *cells_name)
 670 {
 671         return __of_parse_phandle_with_args(np, list_name, cells_name, 0,
 672                                             -1, NULL);
 673 }
 674
 675 static void of_alias_add(struct alias_prop *ap, struct device_node *np,
 676                          int id, const char *stem, int stem_len)
 677 {
 678         ap->np = np;
 679         ap->id = id;
 680         strncpy(ap->stem, stem, stem_len);
 681         ap->stem[stem_len] = 0;
 682         list_add_tail(&ap->link, &aliases_lookup);
 683         debug("adding DT alias:%s: stem=%s id=%i node=%s\n",
 684               ap->alias, ap->stem, ap->id, of_node_full_name(np));
 685 }
 686
 687 int of_alias_scan(void)
 688 {
 689         struct property *pp;
 690
 691         of_aliases = of_find_node_by_path("/aliases");
 692         of_chosen = of_find_node_by_path("/chosen");
 693         if (of_chosen == NULL)
 694                 of_chosen = of_find_node_by_path("/chosen@0");
 695
 696         if (of_chosen) {
 697                 const char *name;
 698
 699                 name = of_get_property(of_chosen, "stdout-path", NULL);
 700                 if (name)
 701                         of_stdout = of_find_node_opts_by_path(name,
 702                                                         &of_stdout_options);
 703         }
 704
 705         if (!of_aliases)
 706                 return 0;
 707
 708         for_each_property_of_node(of_aliases, pp) {
 709                 const char *start = pp->name;
 710                 const char *end = start + strlen(start);
 711                 struct device_node *np;
 712                 struct alias_prop *ap;
 713                 ulong id;
 714                 int len;
 715
 716                 /* Skip those we do not want to proceed */
 717                 if (!strcmp(pp->name, "name") ||
 718                     !strcmp(pp->name, "phandle") ||
 719                     !strcmp(pp->name, "linux,phandle"))
 720                         continue;
 721
 722                 np = of_find_node_by_path(pp->value);
 723                 if (!np)
 724                         continue;
 725
 726                 /*
 727                  * walk the alias backwards to extract the id and work out
 728                  * the 'stem' string
 729                  */
 730                 while (isdigit(*(end-1)) && end > start)
 731                         end--;
 732                 len = end - start;
 733
 734                 if (strict_strtoul(end, 10, &id) < 0)
 735                         continue;
 736
 737                 /* Allocate an alias_prop with enough space for the stem */
 738                 ap = malloc(sizeof(*ap) + len + 1);
 739                 if (!ap)
 740                         return -ENOMEM;
 741                 memset(ap, 0, sizeof(*ap) + len + 1);
 742                 ap->alias = start;
 743                 of_alias_add(ap, np, id, start, len);
 744         }
 745
 746         return 0;
 747 }
 748
 749 int of_alias_get_id(const struct device_node *np, const char *stem)
 750 {
 751         struct alias_prop *app;
 752         int id = -ENODEV;
 753
 754         mutex_lock(&of_mutex);
 755         list_for_each_entry(app, &aliases_lookup, link) {
 756                 if (strcmp(app->stem, stem) != 0)
 757                         continue;
 758
 759                 if (np == app->np) {
 760                         id = app->id;
 761                         break;
 762                 }
 763         }
 764         mutex_unlock(&of_mutex);
 765
 766         return id;
 767 }
 768
 769 struct device_node *of_get_stdout(void)
 770 {
 771         return of_stdout;
 772 }