1 // SPDX-License-Identifier: GPL-2.0+
3 * Originally from Linux v4.9
4 * Paul Mackerras August 1996.
5 * Copyright (C) 1996-2005 Paul Mackerras.
7 * Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
8 * {engebret|bergner}@us.ibm.com
10 * Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net
12 * Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell and
16 * Copyright (c) 2017 Google, Inc
18 * This file follows drivers/of/base.c with functions in the same order as the
24 #include <linux/libfdt.h>
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 const struct property *of_get_first_property(const struct device_node *np)
179 return np->properties;
182 const struct property *of_get_next_property(const struct device_node *np,
183 const struct property *property)
188 return property->next;
191 const void *of_get_property_by_prop(const struct device_node *np,
192 const struct property *property,
196 if (!np || !property)
199 *name = property->name;
201 *lenp = property->length;
203 return property->value;
206 static const char *of_prop_next_string(struct property *prop, const char *cur)
208 const void *curv = cur;
216 curv += strlen(cur) + 1;
217 if (curv >= prop->value + prop->length)
223 int of_device_is_compatible(const struct device_node *device,
224 const char *compat, const char *type,
227 struct property *prop;
229 int index = 0, score = 0;
231 /* Compatible match has highest priority */
232 if (compat && compat[0]) {
233 prop = of_find_property(device, "compatible", NULL);
234 for (cp = of_prop_next_string(prop, NULL); cp;
235 cp = of_prop_next_string(prop, cp), index++) {
236 if (of_compat_cmp(cp, compat, strlen(compat)) == 0) {
237 score = INT_MAX/2 - (index << 2);
245 /* Matching type is better than matching name */
246 if (type && type[0]) {
247 if (!device->type || of_node_cmp(type, device->type))
252 /* Matching name is a bit better than not */
253 if (name && name[0]) {
254 if (!device->name || of_node_cmp(name, device->name))
262 bool of_device_is_available(const struct device_node *device)
270 status = of_get_property(device, "status", &statlen);
275 if (!strcmp(status, "okay"))
282 struct device_node *of_get_parent(const struct device_node *node)
284 const struct device_node *np;
289 np = of_node_get(node->parent);
291 return (struct device_node *)np;
294 static struct device_node *__of_get_next_child(const struct device_node *node,
295 struct device_node *prev)
297 struct device_node *next;
302 next = prev ? prev->sibling : node->child;
304 * coverity[dead_error_line : FALSE]
305 * Dead code here since our current implementation of of_node_get()
306 * always returns NULL (Coverity CID 163245). But we leave it as is
307 * since we may want to implement get/put later.
309 for (; next; next = next->sibling)
310 if (of_node_get(next))
316 #define __for_each_child_of_node(parent, child) \
317 for (child = __of_get_next_child(parent, NULL); child != NULL; \
318 child = __of_get_next_child(parent, child))
320 static struct device_node *__of_find_node_by_path(struct device_node *parent,
323 struct device_node *child;
326 len = strcspn(path, "/:");
330 __for_each_child_of_node(parent, child) {
331 const char *name = strrchr(child->full_name, '/');
334 if (strncmp(path, name, len) == 0 && (strlen(name) == len))
340 #define for_each_property_of_node(dn, pp) \
341 for (pp = dn->properties; pp != NULL; pp = pp->next)
343 struct device_node *of_find_node_opts_by_path(const char *path,
346 struct device_node *np = NULL;
348 const char *separator = strchr(path, ':');
351 *opts = separator ? separator + 1 : NULL;
353 if (strcmp(path, "/") == 0)
354 return of_node_get(gd->of_root);
356 /* The path could begin with an alias */
359 const char *p = separator;
362 p = strchrnul(path, '/');
365 /* of_aliases must not be NULL */
369 for_each_property_of_node(of_aliases, pp) {
370 if (strlen(pp->name) == len && !strncmp(pp->name, path,
372 np = of_find_node_by_path(pp->value);
381 /* Step down the tree matching path components */
383 np = of_node_get(gd->of_root);
384 while (np && *path == '/') {
385 struct device_node *tmp = np;
387 path++; /* Increment past '/' delimiter */
388 np = __of_find_node_by_path(np, path);
390 path = strchrnul(path, '/');
391 if (separator && separator < path)
398 struct device_node *of_find_compatible_node(struct device_node *from,
399 const char *type, const char *compatible)
401 struct device_node *np;
403 for_each_of_allnodes_from(from, np)
404 if (of_device_is_compatible(np, compatible, type, NULL) &&
412 static int of_device_has_prop_value(const struct device_node *device,
413 const char *propname, const void *propval,
416 struct property *prop = of_find_property(device, propname, NULL);
418 if (!prop || !prop->value || prop->length != proplen)
420 return !memcmp(prop->value, propval, proplen);
423 struct device_node *of_find_node_by_prop_value(struct device_node *from,
424 const char *propname,
425 const void *propval, int proplen)
427 struct device_node *np;
429 for_each_of_allnodes_from(from, np) {
430 if (of_device_has_prop_value(np, propname, propval, proplen) &&
439 struct device_node *of_find_node_by_phandle(phandle handle)
441 struct device_node *np;
446 for_each_of_allnodes(np)
447 if (np->phandle == handle)
449 (void)of_node_get(np);
455 * of_find_property_value_of_size() - find property of given size
457 * Search for a property in a device node and validate the requested size.
459 * @np: device node from which the property value is to be read.
460 * @propname: name of the property to be searched.
461 * @len: requested length of property value
463 * @return the property value on success, -EINVAL if the property does not
464 * exist, -ENODATA if property does not have a value, and -EOVERFLOW if the
465 * property data isn't large enough.
467 static void *of_find_property_value_of_size(const struct device_node *np,
468 const char *propname, u32 len)
470 struct property *prop = of_find_property(np, propname, NULL);
473 return ERR_PTR(-EINVAL);
475 return ERR_PTR(-ENODATA);
476 if (len > prop->length)
477 return ERR_PTR(-EOVERFLOW);
482 int of_read_u32(const struct device_node *np, const char *propname, u32 *outp)
484 return of_read_u32_index(np, propname, 0, outp);
487 int of_read_u32_array(const struct device_node *np, const char *propname,
488 u32 *out_values, size_t sz)
492 debug("%s: %s: ", __func__, propname);
493 val = of_find_property_value_of_size(np, propname,
494 sz * sizeof(*out_values));
499 debug("size %zd\n", sz);
501 *out_values++ = be32_to_cpup(val++);
506 int of_read_u32_index(const struct device_node *np, const char *propname,
507 int index, u32 *outp)
511 debug("%s: %s: ", __func__, propname);
515 val = of_find_property_value_of_size(np, propname,
516 sizeof(*outp) * (index + 1));
518 debug("(not found)\n");
522 *outp = be32_to_cpup(val + index);
523 debug("%#x (%d)\n", *outp, *outp);
528 int of_read_u64(const struct device_node *np, const char *propname, u64 *outp)
532 debug("%s: %s: ", __func__, propname);
535 val = of_find_property_value_of_size(np, propname, sizeof(*outp));
537 debug("(not found)\n");
541 *outp = be64_to_cpup(val);
542 debug("%#llx (%lld)\n", (unsigned long long)*outp,
543 (unsigned long long)*outp);
548 int of_property_match_string(const struct device_node *np, const char *propname,
551 const struct property *prop = of_find_property(np, propname, NULL);
562 end = p + prop->length;
564 for (i = 0; p < end; i++, p += l) {
565 l = strnlen(p, end - p) + 1;
568 debug("comparing %s with %s\n", string, p);
569 if (strcmp(string, p) == 0)
570 return i; /* Found it; return index */
576 * of_property_read_string_helper() - Utility helper for parsing string properties
577 * @np: device node from which the property value is to be read.
578 * @propname: name of the property to be searched.
579 * @out_strs: output array of string pointers.
580 * @sz: number of array elements to read.
581 * @skip: Number of strings to skip over at beginning of list.
583 * Don't call this function directly. It is a utility helper for the
584 * of_property_read_string*() family of functions.
586 int of_property_read_string_helper(const struct device_node *np,
587 const char *propname, const char **out_strs,
590 const struct property *prop = of_find_property(np, propname, NULL);
599 end = p + prop->length;
601 for (i = 0; p < end && (!out_strs || i < skip + sz); i++, p += l) {
602 l = strnlen(p, end - p) + 1;
605 if (out_strs && i >= skip)
609 return i <= 0 ? -ENODATA : i;
612 static int __of_parse_phandle_with_args(const struct device_node *np,
613 const char *list_name,
614 const char *cells_name,
615 int cell_count, int index,
616 struct of_phandle_args *out_args)
618 const __be32 *list, *list_end;
619 int rc = 0, cur_index = 0;
621 struct device_node *node = NULL;
625 /* Retrieve the phandle list property */
626 list = of_get_property(np, list_name, &size);
629 list_end = list + size / sizeof(*list);
631 /* Loop over the phandles until all the requested entry is found */
632 while (list < list_end) {
637 * If phandle is 0, then it is an empty entry with no
638 * arguments. Skip forward to the next entry.
640 phandle = be32_to_cpup(list++);
643 * Find the provider node and parse the #*-cells
644 * property to determine the argument length.
646 * This is not needed if the cell count is hard-coded
647 * (i.e. cells_name not set, but cell_count is set),
648 * except when we're going to return the found node
651 if (cells_name || cur_index == index) {
652 node = of_find_node_by_phandle(phandle);
654 debug("%s: could not find phandle\n",
661 if (of_read_u32(node, cells_name, &count)) {
662 debug("%s: could not get %s for %s\n",
663 np->full_name, cells_name,
672 * Make sure that the arguments actually fit in the
673 * remaining property data length
675 if (list + count > list_end) {
676 debug("%s: arguments longer than property\n",
683 * All of the error cases above bail out of the loop, so at
684 * this point, the parsing is successful. If the requested
685 * index matches, then fill the out_args structure and return,
686 * or return -ENOENT for an empty entry.
689 if (cur_index == index) {
695 if (WARN_ON(count > OF_MAX_PHANDLE_ARGS))
696 count = OF_MAX_PHANDLE_ARGS;
698 out_args->args_count = count;
699 for (i = 0; i < count; i++)
701 be32_to_cpup(list++);
706 /* Found it! return success */
717 * Unlock node before returning result; will be one of:
718 * -ENOENT : index is for empty phandle
719 * -EINVAL : parsing error on data
720 * [1..n] : Number of phandle (count mode; when index = -1)
722 rc = index < 0 ? cur_index : -ENOENT;
729 struct device_node *of_parse_phandle(const struct device_node *np,
730 const char *phandle_name, int index)
732 struct of_phandle_args args;
737 if (__of_parse_phandle_with_args(np, phandle_name, NULL, 0, index,
744 int of_parse_phandle_with_args(const struct device_node *np,
745 const char *list_name, const char *cells_name,
746 int index, struct of_phandle_args *out_args)
751 return __of_parse_phandle_with_args(np, list_name, cells_name, 0,
755 int of_count_phandle_with_args(const struct device_node *np,
756 const char *list_name, const char *cells_name)
758 return __of_parse_phandle_with_args(np, list_name, cells_name, 0,
762 static void of_alias_add(struct alias_prop *ap, struct device_node *np,
763 int id, const char *stem, int stem_len)
767 strncpy(ap->stem, stem, stem_len);
768 ap->stem[stem_len] = 0;
769 list_add_tail(&ap->link, &aliases_lookup);
770 debug("adding DT alias:%s: stem=%s id=%i node=%s\n",
771 ap->alias, ap->stem, ap->id, of_node_full_name(np));
774 int of_alias_scan(void)
778 of_aliases = of_find_node_by_path("/aliases");
779 of_chosen = of_find_node_by_path("/chosen");
780 if (of_chosen == NULL)
781 of_chosen = of_find_node_by_path("/chosen@0");
786 name = of_get_property(of_chosen, "stdout-path", NULL);
788 of_stdout = of_find_node_opts_by_path(name,
795 for_each_property_of_node(of_aliases, pp) {
796 const char *start = pp->name;
797 const char *end = start + strlen(start);
798 struct device_node *np;
799 struct alias_prop *ap;
803 /* Skip those we do not want to proceed */
804 if (!strcmp(pp->name, "name") ||
805 !strcmp(pp->name, "phandle") ||
806 !strcmp(pp->name, "linux,phandle"))
809 np = of_find_node_by_path(pp->value);
814 * walk the alias backwards to extract the id and work out
817 while (isdigit(*(end-1)) && end > start)
821 if (strict_strtoul(end, 10, &id) < 0)
824 /* Allocate an alias_prop with enough space for the stem */
825 ap = malloc(sizeof(*ap) + len + 1);
828 memset(ap, 0, sizeof(*ap) + len + 1);
830 of_alias_add(ap, np, id, start, len);
836 int of_alias_get_id(const struct device_node *np, const char *stem)
838 struct alias_prop *app;
841 mutex_lock(&of_mutex);
842 list_for_each_entry(app, &aliases_lookup, link) {
843 if (strcmp(app->stem, stem) != 0)
851 mutex_unlock(&of_mutex);
856 int of_alias_get_highest_id(const char *stem)
858 struct alias_prop *app;
861 mutex_lock(&of_mutex);
862 list_for_each_entry(app, &aliases_lookup, link) {
863 if (strcmp(app->stem, stem) != 0)
869 mutex_unlock(&of_mutex);
874 struct device_node *of_get_stdout(void)