388 lines
9.9 KiB
C
388 lines
9.9 KiB
C
/*
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* Procedures for creating, accessing and interpreting the device tree.
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*
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* Paul Mackerras August 1996.
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* Copyright (C) 1996-2005 Paul Mackerras.
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*
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* Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
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* {engebret|bergner}@us.ibm.com
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*
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* Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net
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*
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* Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/spinlock.h>
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struct device_node *allnodes;
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/* use when traversing tree through the allnext, child, sibling,
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* or parent members of struct device_node.
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*/
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DEFINE_RWLOCK(devtree_lock);
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int of_n_addr_cells(struct device_node *np)
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{
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const int *ip;
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do {
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if (np->parent)
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np = np->parent;
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ip = of_get_property(np, "#address-cells", NULL);
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if (ip)
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return *ip;
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} while (np->parent);
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/* No #address-cells property for the root node */
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return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
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}
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EXPORT_SYMBOL(of_n_addr_cells);
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int of_n_size_cells(struct device_node *np)
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{
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const int *ip;
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do {
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if (np->parent)
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np = np->parent;
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ip = of_get_property(np, "#size-cells", NULL);
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if (ip)
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return *ip;
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} while (np->parent);
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/* No #size-cells property for the root node */
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return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
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}
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EXPORT_SYMBOL(of_n_size_cells);
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struct property *of_find_property(const struct device_node *np,
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const char *name,
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int *lenp)
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{
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struct property *pp;
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if (!np)
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return NULL;
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read_lock(&devtree_lock);
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for (pp = np->properties; pp != 0; pp = pp->next) {
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if (of_prop_cmp(pp->name, name) == 0) {
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if (lenp != 0)
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*lenp = pp->length;
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break;
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}
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}
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read_unlock(&devtree_lock);
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return pp;
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}
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EXPORT_SYMBOL(of_find_property);
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/*
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* Find a property with a given name for a given node
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* and return the value.
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*/
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const void *of_get_property(const struct device_node *np, const char *name,
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int *lenp)
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{
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struct property *pp = of_find_property(np, name, lenp);
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return pp ? pp->value : NULL;
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}
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EXPORT_SYMBOL(of_get_property);
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/** Checks if the given "compat" string matches one of the strings in
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* the device's "compatible" property
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*/
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int of_device_is_compatible(const struct device_node *device,
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const char *compat)
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{
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const char* cp;
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int cplen, l;
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cp = of_get_property(device, "compatible", &cplen);
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if (cp == NULL)
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return 0;
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while (cplen > 0) {
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if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
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return 1;
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l = strlen(cp) + 1;
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cp += l;
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cplen -= l;
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}
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return 0;
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}
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EXPORT_SYMBOL(of_device_is_compatible);
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/**
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* of_device_is_available - check if a device is available for use
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*
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* @device: Node to check for availability
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*
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* Returns 1 if the status property is absent or set to "okay" or "ok",
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* 0 otherwise
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*/
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int of_device_is_available(const struct device_node *device)
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{
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const char *status;
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int statlen;
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status = of_get_property(device, "status", &statlen);
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if (status == NULL)
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return 1;
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if (statlen > 0) {
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if (!strcmp(status, "okay") || !strcmp(status, "ok"))
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return 1;
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}
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return 0;
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}
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EXPORT_SYMBOL(of_device_is_available);
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/**
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* of_get_parent - Get a node's parent if any
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* @node: Node to get parent
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*
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* Returns a node pointer with refcount incremented, use
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* of_node_put() on it when done.
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*/
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struct device_node *of_get_parent(const struct device_node *node)
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{
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struct device_node *np;
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if (!node)
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return NULL;
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read_lock(&devtree_lock);
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np = of_node_get(node->parent);
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read_unlock(&devtree_lock);
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return np;
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}
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EXPORT_SYMBOL(of_get_parent);
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/**
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* of_get_next_parent - Iterate to a node's parent
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* @node: Node to get parent of
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*
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* This is like of_get_parent() except that it drops the
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* refcount on the passed node, making it suitable for iterating
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* through a node's parents.
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*
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* Returns a node pointer with refcount incremented, use
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* of_node_put() on it when done.
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*/
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struct device_node *of_get_next_parent(struct device_node *node)
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{
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struct device_node *parent;
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if (!node)
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return NULL;
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read_lock(&devtree_lock);
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parent = of_node_get(node->parent);
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of_node_put(node);
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read_unlock(&devtree_lock);
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return parent;
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}
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/**
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* of_get_next_child - Iterate a node childs
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* @node: parent node
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* @prev: previous child of the parent node, or NULL to get first
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*
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* Returns a node pointer with refcount incremented, use
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* of_node_put() on it when done.
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*/
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struct device_node *of_get_next_child(const struct device_node *node,
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struct device_node *prev)
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{
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struct device_node *next;
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read_lock(&devtree_lock);
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next = prev ? prev->sibling : node->child;
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for (; next; next = next->sibling)
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if (of_node_get(next))
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break;
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of_node_put(prev);
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read_unlock(&devtree_lock);
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return next;
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}
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EXPORT_SYMBOL(of_get_next_child);
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/**
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* of_find_node_by_path - Find a node matching a full OF path
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* @path: The full path to match
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*
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* Returns a node pointer with refcount incremented, use
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* of_node_put() on it when done.
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*/
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struct device_node *of_find_node_by_path(const char *path)
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{
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struct device_node *np = allnodes;
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read_lock(&devtree_lock);
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for (; np; np = np->allnext) {
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if (np->full_name && (of_node_cmp(np->full_name, path) == 0)
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&& of_node_get(np))
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break;
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}
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read_unlock(&devtree_lock);
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return np;
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}
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EXPORT_SYMBOL(of_find_node_by_path);
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/**
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* of_find_node_by_name - Find a node by its "name" property
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* @from: The node to start searching from or NULL, the node
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* you pass will not be searched, only the next one
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* will; typically, you pass what the previous call
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* returned. of_node_put() will be called on it
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* @name: The name string to match against
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*
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* Returns a node pointer with refcount incremented, use
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* of_node_put() on it when done.
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*/
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struct device_node *of_find_node_by_name(struct device_node *from,
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const char *name)
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{
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struct device_node *np;
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read_lock(&devtree_lock);
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np = from ? from->allnext : allnodes;
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for (; np; np = np->allnext)
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if (np->name && (of_node_cmp(np->name, name) == 0)
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&& of_node_get(np))
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break;
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of_node_put(from);
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read_unlock(&devtree_lock);
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return np;
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}
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EXPORT_SYMBOL(of_find_node_by_name);
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/**
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* of_find_node_by_type - Find a node by its "device_type" property
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* @from: The node to start searching from, or NULL to start searching
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* the entire device tree. The node you pass will not be
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* searched, only the next one will; typically, you pass
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* what the previous call returned. of_node_put() will be
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* called on from for you.
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* @type: The type string to match against
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*
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* Returns a node pointer with refcount incremented, use
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* of_node_put() on it when done.
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*/
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struct device_node *of_find_node_by_type(struct device_node *from,
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const char *type)
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{
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struct device_node *np;
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read_lock(&devtree_lock);
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np = from ? from->allnext : allnodes;
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for (; np; np = np->allnext)
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if (np->type && (of_node_cmp(np->type, type) == 0)
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&& of_node_get(np))
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break;
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of_node_put(from);
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read_unlock(&devtree_lock);
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return np;
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}
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EXPORT_SYMBOL(of_find_node_by_type);
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/**
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* of_find_compatible_node - Find a node based on type and one of the
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* tokens in its "compatible" property
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* @from: The node to start searching from or NULL, the node
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* you pass will not be searched, only the next one
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* will; typically, you pass what the previous call
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* returned. of_node_put() will be called on it
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* @type: The type string to match "device_type" or NULL to ignore
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* @compatible: The string to match to one of the tokens in the device
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* "compatible" list.
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*
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* Returns a node pointer with refcount incremented, use
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* of_node_put() on it when done.
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*/
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struct device_node *of_find_compatible_node(struct device_node *from,
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const char *type, const char *compatible)
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{
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struct device_node *np;
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read_lock(&devtree_lock);
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np = from ? from->allnext : allnodes;
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for (; np; np = np->allnext) {
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if (type
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&& !(np->type && (of_node_cmp(np->type, type) == 0)))
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continue;
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if (of_device_is_compatible(np, compatible) && of_node_get(np))
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break;
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}
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of_node_put(from);
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read_unlock(&devtree_lock);
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return np;
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}
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EXPORT_SYMBOL(of_find_compatible_node);
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/**
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* of_match_node - Tell if an device_node has a matching of_match structure
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* @matches: array of of device match structures to search in
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* @node: the of device structure to match against
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*
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* Low level utility function used by device matching.
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*/
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const struct of_device_id *of_match_node(const struct of_device_id *matches,
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const struct device_node *node)
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{
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while (matches->name[0] || matches->type[0] || matches->compatible[0]) {
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int match = 1;
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if (matches->name[0])
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match &= node->name
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&& !strcmp(matches->name, node->name);
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if (matches->type[0])
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match &= node->type
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&& !strcmp(matches->type, node->type);
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if (matches->compatible[0])
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match &= of_device_is_compatible(node,
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matches->compatible);
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if (match)
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return matches;
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matches++;
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}
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return NULL;
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}
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EXPORT_SYMBOL(of_match_node);
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/**
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* of_find_matching_node - Find a node based on an of_device_id match
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* table.
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* @from: The node to start searching from or NULL, the node
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* you pass will not be searched, only the next one
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* will; typically, you pass what the previous call
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* returned. of_node_put() will be called on it
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* @matches: array of of device match structures to search in
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*
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* Returns a node pointer with refcount incremented, use
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* of_node_put() on it when done.
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*/
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struct device_node *of_find_matching_node(struct device_node *from,
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const struct of_device_id *matches)
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{
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struct device_node *np;
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read_lock(&devtree_lock);
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np = from ? from->allnext : allnodes;
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for (; np; np = np->allnext) {
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if (of_match_node(matches, np) && of_node_get(np))
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break;
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}
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of_node_put(from);
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read_unlock(&devtree_lock);
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return np;
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}
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EXPORT_SYMBOL(of_find_matching_node);
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