2 * Originally from Linux v4.9
3 * Paul Mackerras August 1996.
4 * Copyright (C) 1996-2005 Paul Mackerras.
6 * Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
7 * {engebret|bergner}@us.ibm.com
9 * Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net
11 * Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell and
15 * Copyright (c) 2017 Google, Inc
17 * This file follows drivers/of/base.c with functions in the same order as the
20 * SPDX-License-Identifier: GPL-2.0+
25 #include <dm/of_access.h>
26 #include <linux/ctype.h>
27 #include <linux/err.h>
28 #include <linux/ioport.h>
30 DECLARE_GLOBAL_DATA_PTR;
32 /* list of struct alias_prop aliases */
33 LIST_HEAD(aliases_lookup);
36 static struct device_node *of_aliases;
39 static struct device_node *of_chosen;
41 /* node pointed to by the stdout-path alias */
42 static struct device_node *of_stdout;
44 /* pointer to options given after the alias (separated by :) or NULL if none */
45 static const char *of_stdout_options;
48 * struct alias_prop - Alias property in 'aliases' node
50 * The structure represents one alias property of 'aliases' node as
51 * an entry in aliases_lookup list.
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
60 struct list_head link;
62 struct device_node *np;
67 int of_n_addr_cells(const struct device_node *np)
74 ip = of_get_property(np, "#address-cells", NULL);
76 return be32_to_cpup(ip);
79 /* No #address-cells property for the root node */
80 return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
83 int of_n_size_cells(const struct device_node *np)
90 ip = of_get_property(np, "#size-cells", NULL);
92 return be32_to_cpup(ip);
95 /* No #size-cells property for the root node */
96 return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
99 int of_simple_addr_cells(const struct device_node *np)
103 ip = of_get_property(np, "#address-cells", NULL);
105 return be32_to_cpup(ip);
107 /* Return a default of 2 to match fdt_address_cells()*/
111 int of_simple_size_cells(const struct device_node *np)
115 ip = of_get_property(np, "#size-cells", NULL);
117 return be32_to_cpup(ip);
119 /* Return a default of 2 to match fdt_size_cells()*/
123 struct property *of_find_property(const struct device_node *np,
124 const char *name, int *lenp)
131 for (pp = np->properties; pp; pp = pp->next) {
132 if (strcmp(pp->name, name) == 0) {
139 *lenp = -FDT_ERR_NOTFOUND;
144 struct device_node *of_find_all_nodes(struct device_node *prev)
146 struct device_node *np;
150 } else if (prev->child) {
154 * Walk back up looking for a sibling, or the end of the
158 while (np->parent && !np->sibling)
160 np = np->sibling; /* Might be null at the end of the tree */
166 const void *of_get_property(const struct device_node *np, const char *name,
169 struct property *pp = of_find_property(np, name, lenp);
171 return pp ? pp->value : NULL;
174 static const char *of_prop_next_string(struct property *prop, const char *cur)
176 const void *curv = cur;
184 curv += strlen(cur) + 1;
185 if (curv >= prop->value + prop->length)
191 int of_device_is_compatible(const struct device_node *device,
192 const char *compat, const char *type,
195 struct property *prop;
197 int index = 0, score = 0;
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);
213 /* Matching type is better than matching name */
214 if (type && type[0]) {
215 if (!device->type || of_node_cmp(type, device->type))
220 /* Matching name is a bit better than not */
221 if (name && name[0]) {
222 if (!device->name || of_node_cmp(name, device->name))
230 bool of_device_is_available(const struct device_node *device)
238 status = of_get_property(device, "status", &statlen);
243 if (!strcmp(status, "okay"))
250 struct device_node *of_get_parent(const struct device_node *node)
252 const struct device_node *np;
257 np = of_node_get(node->parent);
259 return (struct device_node *)np;
262 static struct device_node *__of_get_next_child(const struct device_node *node,
263 struct device_node *prev)
265 struct device_node *next;
270 next = prev ? prev->sibling : node->child;
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.
277 for (; next; next = next->sibling)
278 if (of_node_get(next))
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))
288 static struct device_node *__of_find_node_by_path(struct device_node *parent,
291 struct device_node *child;
294 len = strcspn(path, "/:");
298 __for_each_child_of_node(parent, child) {
299 const char *name = strrchr(child->full_name, '/');
302 if (strncmp(path, name, len) == 0 && (strlen(name) == len))
308 #define for_each_property_of_node(dn, pp) \
309 for (pp = dn->properties; pp != NULL; pp = pp->next)
311 struct device_node *of_find_node_opts_by_path(const char *path,
314 struct device_node *np = NULL;
316 const char *separator = strchr(path, ':');
319 *opts = separator ? separator + 1 : NULL;
321 if (strcmp(path, "/") == 0)
322 return of_node_get(gd->of_root);
324 /* The path could begin with an alias */
327 const char *p = separator;
330 p = strchrnul(path, '/');
333 /* of_aliases must not be NULL */
337 for_each_property_of_node(of_aliases, pp) {
338 if (strlen(pp->name) == len && !strncmp(pp->name, path,
340 np = of_find_node_by_path(pp->value);
349 /* Step down the tree matching path components */
351 np = of_node_get(gd->of_root);
352 while (np && *path == '/') {
353 struct device_node *tmp = np;
355 path++; /* Increment past '/' delimiter */
356 np = __of_find_node_by_path(np, path);
358 path = strchrnul(path, '/');
359 if (separator && separator < path)
366 struct device_node *of_find_compatible_node(struct device_node *from,
367 const char *type, const char *compatible)
369 struct device_node *np;
371 for_each_of_allnodes_from(from, np)
372 if (of_device_is_compatible(np, compatible, type, NULL) &&
380 struct device_node *of_find_node_by_phandle(phandle handle)
382 struct device_node *np;
387 for_each_of_allnodes(np)
388 if (np->phandle == handle)
390 (void)of_node_get(np);
396 * of_find_property_value_of_size() - find property of given size
398 * Search for a property in a device node and validate the requested size.
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
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.
408 static void *of_find_property_value_of_size(const struct device_node *np,
409 const char *propname, u32 len)
411 struct property *prop = of_find_property(np, propname, NULL);
414 return ERR_PTR(-EINVAL);
416 return ERR_PTR(-ENODATA);
417 if (len > prop->length)
418 return ERR_PTR(-EOVERFLOW);
423 int of_read_u32(const struct device_node *np, const char *propname, u32 *outp)
427 debug("%s: %s: ", __func__, propname);
430 val = of_find_property_value_of_size(np, propname, sizeof(*outp));
432 debug("(not found)\n");
436 *outp = be32_to_cpup(val);
437 debug("%#x (%d)\n", *outp, *outp);
442 int of_read_u32_array(const struct device_node *np, const char *propname,
443 u32 *out_values, size_t sz)
447 debug("%s: %s: ", __func__, propname);
448 val = of_find_property_value_of_size(np, propname,
449 sz * sizeof(*out_values));
454 debug("size %zd\n", sz);
456 *out_values++ = be32_to_cpup(val++);
461 int of_property_match_string(const struct device_node *np, const char *propname,
464 const struct property *prop = of_find_property(np, propname, NULL);
475 end = p + prop->length;
477 for (i = 0; p < end; i++, p += l) {
478 l = strnlen(p, end - p) + 1;
481 debug("comparing %s with %s\n", string, p);
482 if (strcmp(string, p) == 0)
483 return i; /* Found it; return index */
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.
496 * Don't call this function directly. It is a utility helper for the
497 * of_property_read_string*() family of functions.
499 int of_property_read_string_helper(const struct device_node *np,
500 const char *propname, const char **out_strs,
503 const struct property *prop = of_find_property(np, propname, NULL);
512 end = p + prop->length;
514 for (i = 0; p < end && (!out_strs || i < skip + sz); i++, p += l) {
515 l = strnlen(p, end - p) + 1;
518 if (out_strs && i >= skip)
522 return i <= 0 ? -ENODATA : i;
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)
531 const __be32 *list, *list_end;
532 int rc = 0, cur_index = 0;
534 struct device_node *node = NULL;
538 /* Retrieve the phandle list property */
539 list = of_get_property(np, list_name, &size);
542 list_end = list + size / sizeof(*list);
544 /* Loop over the phandles until all the requested entry is found */
545 while (list < list_end) {
550 * If phandle is 0, then it is an empty entry with no
551 * arguments. Skip forward to the next entry.
553 phandle = be32_to_cpup(list++);
556 * Find the provider node and parse the #*-cells
557 * property to determine the argument length.
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
564 if (cells_name || cur_index == index) {
565 node = of_find_node_by_phandle(phandle);
567 debug("%s: could not find phandle\n",
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,
585 * Make sure that the arguments actually fit in the
586 * remaining property data length
588 if (list + count > list_end) {
589 debug("%s: arguments longer than property\n",
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.
602 if (cur_index == index) {
608 if (WARN_ON(count > OF_MAX_PHANDLE_ARGS))
609 count = OF_MAX_PHANDLE_ARGS;
611 out_args->args_count = count;
612 for (i = 0; i < count; i++)
614 be32_to_cpup(list++);
619 /* Found it! return success */
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)
635 rc = index < 0 ? cur_index : -ENOENT;
642 struct device_node *of_parse_phandle(const struct device_node *np,
643 const char *phandle_name, int index)
645 struct of_phandle_args args;
650 if (__of_parse_phandle_with_args(np, phandle_name, NULL, 0, index,
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)
664 return __of_parse_phandle_with_args(np, list_name, cells_name, 0,
668 int of_count_phandle_with_args(const struct device_node *np,
669 const char *list_name, const char *cells_name)
671 return __of_parse_phandle_with_args(np, list_name, cells_name, 0,
675 static void of_alias_add(struct alias_prop *ap, struct device_node *np,
676 int id, const char *stem, int stem_len)
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));
687 int of_alias_scan(void)
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");
699 name = of_get_property(of_chosen, "stdout-path", NULL);
701 of_stdout = of_find_node_opts_by_path(name,
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;
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"))
722 np = of_find_node_by_path(pp->value);
727 * walk the alias backwards to extract the id and work out
730 while (isdigit(*(end-1)) && end > start)
734 if (strict_strtoul(end, 10, &id) < 0)
737 /* Allocate an alias_prop with enough space for the stem */
738 ap = malloc(sizeof(*ap) + len + 1);
741 memset(ap, 0, sizeof(*ap) + len + 1);
743 of_alias_add(ap, np, id, start, len);
749 int of_alias_get_id(const struct device_node *np, const char *stem)
751 struct alias_prop *app;
754 mutex_lock(&of_mutex);
755 list_for_each_entry(app, &aliases_lookup, link) {
756 if (strcmp(app->stem, stem) != 0)
764 mutex_unlock(&of_mutex);
769 struct device_node *of_get_stdout(void)