ia64/kvm: compilation fix. export account_system_vtime.
[pv_ops_mirror.git] / drivers / of / base.c
blob23ffb7c0caf24148277ddd19c7430b5c90fb6fcb
1 /*
2 * Procedures for creating, accessing and interpreting the device tree.
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.
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.
19 #include <linux/module.h>
20 #include <linux/of.h>
21 #include <linux/spinlock.h>
23 struct device_node *allnodes;
25 /* use when traversing tree through the allnext, child, sibling,
26 * or parent members of struct device_node.
28 DEFINE_RWLOCK(devtree_lock);
30 int of_n_addr_cells(struct device_node *np)
32 const int *ip;
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;
44 EXPORT_SYMBOL(of_n_addr_cells);
46 int of_n_size_cells(struct device_node *np)
48 const int *ip;
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;
60 EXPORT_SYMBOL(of_n_size_cells);
62 struct property *of_find_property(const struct device_node *np,
63 const char *name,
64 int *lenp)
66 struct property *pp;
68 if (!np)
69 return NULL;
71 read_lock(&devtree_lock);
72 for (pp = np->properties; pp != 0; pp = pp->next) {
73 if (of_prop_cmp(pp->name, name) == 0) {
74 if (lenp != 0)
75 *lenp = pp->length;
76 break;
79 read_unlock(&devtree_lock);
81 return pp;
83 EXPORT_SYMBOL(of_find_property);
86 * Find a property with a given name for a given node
87 * and return the value.
89 const void *of_get_property(const struct device_node *np, const char *name,
90 int *lenp)
92 struct property *pp = of_find_property(np, name, lenp);
94 return pp ? pp->value : NULL;
96 EXPORT_SYMBOL(of_get_property);
98 /** Checks if the given "compat" string matches one of the strings in
99 * the device's "compatible" property
101 int of_device_is_compatible(const struct device_node *device,
102 const char *compat)
104 const char* cp;
105 int cplen, l;
107 cp = of_get_property(device, "compatible", &cplen);
108 if (cp == NULL)
109 return 0;
110 while (cplen > 0) {
111 if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
112 return 1;
113 l = strlen(cp) + 1;
114 cp += l;
115 cplen -= l;
118 return 0;
120 EXPORT_SYMBOL(of_device_is_compatible);
123 * of_device_is_available - check if a device is available for use
125 * @device: Node to check for availability
127 * Returns 1 if the status property is absent or set to "okay" or "ok",
128 * 0 otherwise
130 int of_device_is_available(const struct device_node *device)
132 const char *status;
133 int statlen;
135 status = of_get_property(device, "status", &statlen);
136 if (status == NULL)
137 return 1;
139 if (statlen > 0) {
140 if (!strcmp(status, "okay") || !strcmp(status, "ok"))
141 return 1;
144 return 0;
146 EXPORT_SYMBOL(of_device_is_available);
149 * of_get_parent - Get a node's parent if any
150 * @node: Node to get parent
152 * Returns a node pointer with refcount incremented, use
153 * of_node_put() on it when done.
155 struct device_node *of_get_parent(const struct device_node *node)
157 struct device_node *np;
159 if (!node)
160 return NULL;
162 read_lock(&devtree_lock);
163 np = of_node_get(node->parent);
164 read_unlock(&devtree_lock);
165 return np;
167 EXPORT_SYMBOL(of_get_parent);
170 * of_get_next_parent - Iterate to a node's parent
171 * @node: Node to get parent of
173 * This is like of_get_parent() except that it drops the
174 * refcount on the passed node, making it suitable for iterating
175 * through a node's parents.
177 * Returns a node pointer with refcount incremented, use
178 * of_node_put() on it when done.
180 struct device_node *of_get_next_parent(struct device_node *node)
182 struct device_node *parent;
184 if (!node)
185 return NULL;
187 read_lock(&devtree_lock);
188 parent = of_node_get(node->parent);
189 of_node_put(node);
190 read_unlock(&devtree_lock);
191 return parent;
195 * of_get_next_child - Iterate a node childs
196 * @node: parent node
197 * @prev: previous child of the parent node, or NULL to get first
199 * Returns a node pointer with refcount incremented, use
200 * of_node_put() on it when done.
202 struct device_node *of_get_next_child(const struct device_node *node,
203 struct device_node *prev)
205 struct device_node *next;
207 read_lock(&devtree_lock);
208 next = prev ? prev->sibling : node->child;
209 for (; next; next = next->sibling)
210 if (of_node_get(next))
211 break;
212 of_node_put(prev);
213 read_unlock(&devtree_lock);
214 return next;
216 EXPORT_SYMBOL(of_get_next_child);
219 * of_find_node_by_path - Find a node matching a full OF path
220 * @path: The full path to match
222 * Returns a node pointer with refcount incremented, use
223 * of_node_put() on it when done.
225 struct device_node *of_find_node_by_path(const char *path)
227 struct device_node *np = allnodes;
229 read_lock(&devtree_lock);
230 for (; np; np = np->allnext) {
231 if (np->full_name && (of_node_cmp(np->full_name, path) == 0)
232 && of_node_get(np))
233 break;
235 read_unlock(&devtree_lock);
236 return np;
238 EXPORT_SYMBOL(of_find_node_by_path);
241 * of_find_node_by_name - Find a node by its "name" property
242 * @from: The node to start searching from or NULL, the node
243 * you pass will not be searched, only the next one
244 * will; typically, you pass what the previous call
245 * returned. of_node_put() will be called on it
246 * @name: The name string to match against
248 * Returns a node pointer with refcount incremented, use
249 * of_node_put() on it when done.
251 struct device_node *of_find_node_by_name(struct device_node *from,
252 const char *name)
254 struct device_node *np;
256 read_lock(&devtree_lock);
257 np = from ? from->allnext : allnodes;
258 for (; np; np = np->allnext)
259 if (np->name && (of_node_cmp(np->name, name) == 0)
260 && of_node_get(np))
261 break;
262 of_node_put(from);
263 read_unlock(&devtree_lock);
264 return np;
266 EXPORT_SYMBOL(of_find_node_by_name);
269 * of_find_node_by_type - Find a node by its "device_type" property
270 * @from: The node to start searching from, or NULL to start searching
271 * the entire device tree. The node you pass will not be
272 * searched, only the next one will; typically, you pass
273 * what the previous call returned. of_node_put() will be
274 * called on from for you.
275 * @type: The type string to match against
277 * Returns a node pointer with refcount incremented, use
278 * of_node_put() on it when done.
280 struct device_node *of_find_node_by_type(struct device_node *from,
281 const char *type)
283 struct device_node *np;
285 read_lock(&devtree_lock);
286 np = from ? from->allnext : allnodes;
287 for (; np; np = np->allnext)
288 if (np->type && (of_node_cmp(np->type, type) == 0)
289 && of_node_get(np))
290 break;
291 of_node_put(from);
292 read_unlock(&devtree_lock);
293 return np;
295 EXPORT_SYMBOL(of_find_node_by_type);
298 * of_find_compatible_node - Find a node based on type and one of the
299 * tokens in its "compatible" property
300 * @from: The node to start searching from or NULL, the node
301 * you pass will not be searched, only the next one
302 * will; typically, you pass what the previous call
303 * returned. of_node_put() will be called on it
304 * @type: The type string to match "device_type" or NULL to ignore
305 * @compatible: The string to match to one of the tokens in the device
306 * "compatible" list.
308 * Returns a node pointer with refcount incremented, use
309 * of_node_put() on it when done.
311 struct device_node *of_find_compatible_node(struct device_node *from,
312 const char *type, const char *compatible)
314 struct device_node *np;
316 read_lock(&devtree_lock);
317 np = from ? from->allnext : allnodes;
318 for (; np; np = np->allnext) {
319 if (type
320 && !(np->type && (of_node_cmp(np->type, type) == 0)))
321 continue;
322 if (of_device_is_compatible(np, compatible) && of_node_get(np))
323 break;
325 of_node_put(from);
326 read_unlock(&devtree_lock);
327 return np;
329 EXPORT_SYMBOL(of_find_compatible_node);
332 * of_match_node - Tell if an device_node has a matching of_match structure
333 * @matches: array of of device match structures to search in
334 * @node: the of device structure to match against
336 * Low level utility function used by device matching.
338 const struct of_device_id *of_match_node(const struct of_device_id *matches,
339 const struct device_node *node)
341 while (matches->name[0] || matches->type[0] || matches->compatible[0]) {
342 int match = 1;
343 if (matches->name[0])
344 match &= node->name
345 && !strcmp(matches->name, node->name);
346 if (matches->type[0])
347 match &= node->type
348 && !strcmp(matches->type, node->type);
349 if (matches->compatible[0])
350 match &= of_device_is_compatible(node,
351 matches->compatible);
352 if (match)
353 return matches;
354 matches++;
356 return NULL;
358 EXPORT_SYMBOL(of_match_node);
361 * of_find_matching_node - Find a node based on an of_device_id match
362 * table.
363 * @from: The node to start searching from or NULL, the node
364 * you pass will not be searched, only the next one
365 * will; typically, you pass what the previous call
366 * returned. of_node_put() will be called on it
367 * @matches: array of of device match structures to search in
369 * Returns a node pointer with refcount incremented, use
370 * of_node_put() on it when done.
372 struct device_node *of_find_matching_node(struct device_node *from,
373 const struct of_device_id *matches)
375 struct device_node *np;
377 read_lock(&devtree_lock);
378 np = from ? from->allnext : allnodes;
379 for (; np; np = np->allnext) {
380 if (of_match_node(matches, np) && of_node_get(np))
381 break;
383 of_node_put(from);
384 read_unlock(&devtree_lock);
385 return np;
387 EXPORT_SYMBOL(of_find_matching_node);