blob: 9377f3bc410ac0083e96f3fefb48400ae4342a43 [file] [log] [blame]
Stephen Rothwell97e873e2007-05-01 16:26:07 +10001/*
2 * Procedures for creating, accessing and interpreting the device tree.
3 *
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.
13 *
14 * This program is free software; you can redistribute it and/or
15 * modify it under the terms of the GNU General Public License
16 * as published by the Free Software Foundation; either version
17 * 2 of the License, or (at your option) any later version.
18 */
19#include <linux/module.h>
20#include <linux/of.h>
Stephen Rothwell581b6052007-04-24 16:46:53 +100021#include <linux/spinlock.h>
22
Stephen Rothwell1ef4d422007-04-24 17:57:33 +100023struct device_node *allnodes;
24
Stephen Rothwell581b6052007-04-24 16:46:53 +100025/* use when traversing tree through the allnext, child, sibling,
26 * or parent members of struct device_node.
27 */
28DEFINE_RWLOCK(devtree_lock);
Stephen Rothwell97e873e2007-05-01 16:26:07 +100029
30int of_n_addr_cells(struct device_node *np)
31{
32 const int *ip;
33
34 do {
35 if (np->parent)
36 np = np->parent;
37 ip = of_get_property(np, "#address-cells", NULL);
38 if (ip)
39 return *ip;
40 } while (np->parent);
41 /* No #address-cells property for the root node */
42 return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
43}
44EXPORT_SYMBOL(of_n_addr_cells);
45
46int of_n_size_cells(struct device_node *np)
47{
48 const int *ip;
49
50 do {
51 if (np->parent)
52 np = np->parent;
53 ip = of_get_property(np, "#size-cells", NULL);
54 if (ip)
55 return *ip;
56 } while (np->parent);
57 /* No #size-cells property for the root node */
58 return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
59}
60EXPORT_SYMBOL(of_n_size_cells);
61
Stephen Rothwell581b6052007-04-24 16:46:53 +100062struct property *of_find_property(const struct device_node *np,
63 const char *name,
64 int *lenp)
65{
66 struct property *pp;
67
68 read_lock(&devtree_lock);
69 for (pp = np->properties; pp != 0; pp = pp->next) {
70 if (of_prop_cmp(pp->name, name) == 0) {
71 if (lenp != 0)
72 *lenp = pp->length;
73 break;
74 }
75 }
76 read_unlock(&devtree_lock);
77
78 return pp;
79}
80EXPORT_SYMBOL(of_find_property);
81
Stephen Rothwell97e873e2007-05-01 16:26:07 +100082/*
83 * Find a property with a given name for a given node
84 * and return the value.
85 */
86const void *of_get_property(const struct device_node *np, const char *name,
87 int *lenp)
88{
89 struct property *pp = of_find_property(np, name, lenp);
90
91 return pp ? pp->value : NULL;
92}
93EXPORT_SYMBOL(of_get_property);
Stephen Rothwell0081cbc2007-05-01 16:29:19 +100094
95/** Checks if the given "compat" string matches one of the strings in
96 * the device's "compatible" property
97 */
98int of_device_is_compatible(const struct device_node *device,
99 const char *compat)
100{
101 const char* cp;
102 int cplen, l;
103
104 cp = of_get_property(device, "compatible", &cplen);
105 if (cp == NULL)
106 return 0;
107 while (cplen > 0) {
108 if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
109 return 1;
110 l = strlen(cp) + 1;
111 cp += l;
112 cplen -= l;
113 }
114
115 return 0;
116}
117EXPORT_SYMBOL(of_device_is_compatible);
Stephen Rothwelle679c5f2007-04-24 17:16:16 +1000118
119/**
120 * of_get_parent - Get a node's parent if any
121 * @node: Node to get parent
122 *
123 * Returns a node pointer with refcount incremented, use
124 * of_node_put() on it when done.
125 */
126struct device_node *of_get_parent(const struct device_node *node)
127{
128 struct device_node *np;
129
130 if (!node)
131 return NULL;
132
133 read_lock(&devtree_lock);
134 np = of_node_get(node->parent);
135 read_unlock(&devtree_lock);
136 return np;
137}
138EXPORT_SYMBOL(of_get_parent);
Stephen Rothwelld1cd3552007-04-24 17:21:29 +1000139
140/**
141 * of_get_next_child - Iterate a node childs
142 * @node: parent node
143 * @prev: previous child of the parent node, or NULL to get first
144 *
145 * Returns a node pointer with refcount incremented, use
146 * of_node_put() on it when done.
147 */
148struct device_node *of_get_next_child(const struct device_node *node,
149 struct device_node *prev)
150{
151 struct device_node *next;
152
153 read_lock(&devtree_lock);
154 next = prev ? prev->sibling : node->child;
155 for (; next; next = next->sibling)
156 if (of_node_get(next))
157 break;
158 of_node_put(prev);
159 read_unlock(&devtree_lock);
160 return next;
161}
162EXPORT_SYMBOL(of_get_next_child);
Stephen Rothwell1ef4d422007-04-24 17:57:33 +1000163
164/**
165 * of_find_node_by_path - Find a node matching a full OF path
166 * @path: The full path to match
167 *
168 * Returns a node pointer with refcount incremented, use
169 * of_node_put() on it when done.
170 */
171struct device_node *of_find_node_by_path(const char *path)
172{
173 struct device_node *np = allnodes;
174
175 read_lock(&devtree_lock);
176 for (; np; np = np->allnext) {
177 if (np->full_name && (of_node_cmp(np->full_name, path) == 0)
178 && of_node_get(np))
179 break;
180 }
181 read_unlock(&devtree_lock);
182 return np;
183}
184EXPORT_SYMBOL(of_find_node_by_path);
185
186/**
187 * of_find_node_by_name - Find a node by its "name" property
188 * @from: The node to start searching from or NULL, the node
189 * you pass will not be searched, only the next one
190 * will; typically, you pass what the previous call
191 * returned. of_node_put() will be called on it
192 * @name: The name string to match against
193 *
194 * Returns a node pointer with refcount incremented, use
195 * of_node_put() on it when done.
196 */
197struct device_node *of_find_node_by_name(struct device_node *from,
198 const char *name)
199{
200 struct device_node *np;
201
202 read_lock(&devtree_lock);
203 np = from ? from->allnext : allnodes;
204 for (; np; np = np->allnext)
205 if (np->name && (of_node_cmp(np->name, name) == 0)
206 && of_node_get(np))
207 break;
208 of_node_put(from);
209 read_unlock(&devtree_lock);
210 return np;
211}
212EXPORT_SYMBOL(of_find_node_by_name);
213
214/**
215 * of_find_node_by_type - Find a node by its "device_type" property
216 * @from: The node to start searching from, or NULL to start searching
217 * the entire device tree. The node you pass will not be
218 * searched, only the next one will; typically, you pass
219 * what the previous call returned. of_node_put() will be
220 * called on from for you.
221 * @type: The type string to match against
222 *
223 * Returns a node pointer with refcount incremented, use
224 * of_node_put() on it when done.
225 */
226struct device_node *of_find_node_by_type(struct device_node *from,
227 const char *type)
228{
229 struct device_node *np;
230
231 read_lock(&devtree_lock);
232 np = from ? from->allnext : allnodes;
233 for (; np; np = np->allnext)
234 if (np->type && (of_node_cmp(np->type, type) == 0)
235 && of_node_get(np))
236 break;
237 of_node_put(from);
238 read_unlock(&devtree_lock);
239 return np;
240}
241EXPORT_SYMBOL(of_find_node_by_type);
242
243/**
244 * of_find_compatible_node - Find a node based on type and one of the
245 * tokens in its "compatible" property
246 * @from: The node to start searching from or NULL, the node
247 * you pass will not be searched, only the next one
248 * will; typically, you pass what the previous call
249 * returned. of_node_put() will be called on it
250 * @type: The type string to match "device_type" or NULL to ignore
251 * @compatible: The string to match to one of the tokens in the device
252 * "compatible" list.
253 *
254 * Returns a node pointer with refcount incremented, use
255 * of_node_put() on it when done.
256 */
257struct device_node *of_find_compatible_node(struct device_node *from,
258 const char *type, const char *compatible)
259{
260 struct device_node *np;
261
262 read_lock(&devtree_lock);
263 np = from ? from->allnext : allnodes;
264 for (; np; np = np->allnext) {
265 if (type
266 && !(np->type && (of_node_cmp(np->type, type) == 0)))
267 continue;
268 if (of_device_is_compatible(np, compatible) && of_node_get(np))
269 break;
270 }
271 of_node_put(from);
272 read_unlock(&devtree_lock);
273 return np;
274}
275EXPORT_SYMBOL(of_find_compatible_node);