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![Grant Likely](/assets/img/avatar_default.png)
There are a few use cases where it is convenient to pass NULL to of_match_node() and have it fail gracefully. The patch adds a null check to the beginning so taht it does so. Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
924 lines
23 KiB
C
924 lines
23 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 and
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* Grant Likely.
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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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#include <linux/slab.h>
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#include <linux/proc_fs.h>
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struct device_node *allnodes;
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struct device_node *of_chosen;
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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 __be32 *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 be32_to_cpup(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 __be32 *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 be32_to_cpup(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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#if !defined(CONFIG_SPARC) /* SPARC doesn't do ref counting (yet) */
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/**
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* of_node_get - Increment refcount of a node
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* @node: Node to inc refcount, NULL is supported to
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* simplify writing of callers
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*
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* Returns node.
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*/
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struct device_node *of_node_get(struct device_node *node)
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{
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if (node)
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kref_get(&node->kref);
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return node;
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}
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EXPORT_SYMBOL(of_node_get);
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static inline struct device_node *kref_to_device_node(struct kref *kref)
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{
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return container_of(kref, struct device_node, kref);
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}
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/**
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* of_node_release - release a dynamically allocated node
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* @kref: kref element of the node to be released
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*
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* In of_node_put() this function is passed to kref_put()
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* as the destructor.
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*/
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static void of_node_release(struct kref *kref)
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{
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struct device_node *node = kref_to_device_node(kref);
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struct property *prop = node->properties;
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/* We should never be releasing nodes that haven't been detached. */
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if (!of_node_check_flag(node, OF_DETACHED)) {
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pr_err("ERROR: Bad of_node_put() on %s\n", node->full_name);
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dump_stack();
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kref_init(&node->kref);
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return;
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}
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if (!of_node_check_flag(node, OF_DYNAMIC))
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return;
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while (prop) {
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struct property *next = prop->next;
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kfree(prop->name);
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kfree(prop->value);
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kfree(prop);
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prop = next;
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if (!prop) {
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prop = node->deadprops;
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node->deadprops = NULL;
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}
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}
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kfree(node->full_name);
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kfree(node->data);
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kfree(node);
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}
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/**
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* of_node_put - Decrement refcount of a node
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* @node: Node to dec refcount, NULL is supported to
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* simplify writing of callers
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*
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*/
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void of_node_put(struct device_node *node)
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{
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if (node)
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kref_put(&node->kref, of_node_release);
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}
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EXPORT_SYMBOL(of_node_put);
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#endif /* !CONFIG_SPARC */
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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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* of_find_all_nodes - Get next node in global list
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* @prev: Previous node or NULL to start iteration
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* of_node_put() will be called on it
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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_all_nodes(struct device_node *prev)
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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 = prev ? prev->allnext : allnodes;
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for (; np != NULL; np = np->allnext)
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if (of_node_get(np))
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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 np;
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}
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EXPORT_SYMBOL(of_find_all_nodes);
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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_machine_is_compatible - Test root of device tree for a given compatible value
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* @compat: compatible string to look for in root node's compatible property.
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*
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* Returns true if the root node has the given value in its
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* compatible property.
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*/
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int of_machine_is_compatible(const char *compat)
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{
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struct device_node *root;
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int rc = 0;
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root = of_find_node_by_path("/");
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if (root) {
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rc = of_device_is_compatible(root, compat);
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of_node_put(root);
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}
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return rc;
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}
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EXPORT_SYMBOL(of_machine_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_find_node_with_property - Find a node which has a property with
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* the given name.
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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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* @prop_name: The name of the property to look for.
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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_with_property(struct device_node *from,
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const char *prop_name)
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{
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struct device_node *np;
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struct property *pp;
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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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for (pp = np->properties; pp != 0; pp = pp->next) {
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if (of_prop_cmp(pp->name, prop_name) == 0) {
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of_node_get(np);
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goto out;
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}
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}
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}
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out:
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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_with_property);
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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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if (!matches)
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return NULL;
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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
|
|
*
|
|
* Returns a node pointer with refcount incremented, use
|
|
* of_node_put() on it when done.
|
|
*/
|
|
struct device_node *of_find_matching_node(struct device_node *from,
|
|
const struct of_device_id *matches)
|
|
{
|
|
struct device_node *np;
|
|
|
|
read_lock(&devtree_lock);
|
|
np = from ? from->allnext : allnodes;
|
|
for (; np; np = np->allnext) {
|
|
if (of_match_node(matches, np) && of_node_get(np))
|
|
break;
|
|
}
|
|
of_node_put(from);
|
|
read_unlock(&devtree_lock);
|
|
return np;
|
|
}
|
|
EXPORT_SYMBOL(of_find_matching_node);
|
|
|
|
/**
|
|
* of_modalias_node - Lookup appropriate modalias for a device node
|
|
* @node: pointer to a device tree node
|
|
* @modalias: Pointer to buffer that modalias value will be copied into
|
|
* @len: Length of modalias value
|
|
*
|
|
* Based on the value of the compatible property, this routine will attempt
|
|
* to choose an appropriate modalias value for a particular device tree node.
|
|
* It does this by stripping the manufacturer prefix (as delimited by a ',')
|
|
* from the first entry in the compatible list property.
|
|
*
|
|
* This routine returns 0 on success, <0 on failure.
|
|
*/
|
|
int of_modalias_node(struct device_node *node, char *modalias, int len)
|
|
{
|
|
const char *compatible, *p;
|
|
int cplen;
|
|
|
|
compatible = of_get_property(node, "compatible", &cplen);
|
|
if (!compatible || strlen(compatible) > cplen)
|
|
return -ENODEV;
|
|
p = strchr(compatible, ',');
|
|
strlcpy(modalias, p ? p + 1 : compatible, len);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(of_modalias_node);
|
|
|
|
/**
|
|
* of_find_node_by_phandle - Find a node given a phandle
|
|
* @handle: phandle of the node to find
|
|
*
|
|
* Returns a node pointer with refcount incremented, use
|
|
* of_node_put() on it when done.
|
|
*/
|
|
struct device_node *of_find_node_by_phandle(phandle handle)
|
|
{
|
|
struct device_node *np;
|
|
|
|
read_lock(&devtree_lock);
|
|
for (np = allnodes; np; np = np->allnext)
|
|
if (np->phandle == handle)
|
|
break;
|
|
of_node_get(np);
|
|
read_unlock(&devtree_lock);
|
|
return np;
|
|
}
|
|
EXPORT_SYMBOL(of_find_node_by_phandle);
|
|
|
|
/**
|
|
* of_parse_phandle - Resolve a phandle property to a device_node pointer
|
|
* @np: Pointer to device node holding phandle property
|
|
* @phandle_name: Name of property holding a phandle value
|
|
* @index: For properties holding a table of phandles, this is the index into
|
|
* the table
|
|
*
|
|
* Returns the device_node pointer with refcount incremented. Use
|
|
* of_node_put() on it when done.
|
|
*/
|
|
struct device_node *
|
|
of_parse_phandle(struct device_node *np, const char *phandle_name, int index)
|
|
{
|
|
const __be32 *phandle;
|
|
int size;
|
|
|
|
phandle = of_get_property(np, phandle_name, &size);
|
|
if ((!phandle) || (size < sizeof(*phandle) * (index + 1)))
|
|
return NULL;
|
|
|
|
return of_find_node_by_phandle(be32_to_cpup(phandle + index));
|
|
}
|
|
EXPORT_SYMBOL(of_parse_phandle);
|
|
|
|
/**
|
|
* of_parse_phandles_with_args - Find a node pointed by phandle in a list
|
|
* @np: pointer to a device tree node containing a list
|
|
* @list_name: property name that contains a list
|
|
* @cells_name: property name that specifies phandles' arguments count
|
|
* @index: index of a phandle to parse out
|
|
* @out_node: optional pointer to device_node struct pointer (will be filled)
|
|
* @out_args: optional pointer to arguments pointer (will be filled)
|
|
*
|
|
* This function is useful to parse lists of phandles and their arguments.
|
|
* Returns 0 on success and fills out_node and out_args, on error returns
|
|
* appropriate errno value.
|
|
*
|
|
* Example:
|
|
*
|
|
* phandle1: node1 {
|
|
* #list-cells = <2>;
|
|
* }
|
|
*
|
|
* phandle2: node2 {
|
|
* #list-cells = <1>;
|
|
* }
|
|
*
|
|
* node3 {
|
|
* list = <&phandle1 1 2 &phandle2 3>;
|
|
* }
|
|
*
|
|
* To get a device_node of the `node2' node you may call this:
|
|
* of_parse_phandles_with_args(node3, "list", "#list-cells", 2, &node2, &args);
|
|
*/
|
|
int of_parse_phandles_with_args(struct device_node *np, const char *list_name,
|
|
const char *cells_name, int index,
|
|
struct device_node **out_node,
|
|
const void **out_args)
|
|
{
|
|
int ret = -EINVAL;
|
|
const __be32 *list;
|
|
const __be32 *list_end;
|
|
int size;
|
|
int cur_index = 0;
|
|
struct device_node *node = NULL;
|
|
const void *args = NULL;
|
|
|
|
list = of_get_property(np, list_name, &size);
|
|
if (!list) {
|
|
ret = -ENOENT;
|
|
goto err0;
|
|
}
|
|
list_end = list + size / sizeof(*list);
|
|
|
|
while (list < list_end) {
|
|
const __be32 *cells;
|
|
phandle phandle;
|
|
|
|
phandle = be32_to_cpup(list++);
|
|
args = list;
|
|
|
|
/* one cell hole in the list = <>; */
|
|
if (!phandle)
|
|
goto next;
|
|
|
|
node = of_find_node_by_phandle(phandle);
|
|
if (!node) {
|
|
pr_debug("%s: could not find phandle\n",
|
|
np->full_name);
|
|
goto err0;
|
|
}
|
|
|
|
cells = of_get_property(node, cells_name, &size);
|
|
if (!cells || size != sizeof(*cells)) {
|
|
pr_debug("%s: could not get %s for %s\n",
|
|
np->full_name, cells_name, node->full_name);
|
|
goto err1;
|
|
}
|
|
|
|
list += be32_to_cpup(cells);
|
|
if (list > list_end) {
|
|
pr_debug("%s: insufficient arguments length\n",
|
|
np->full_name);
|
|
goto err1;
|
|
}
|
|
next:
|
|
if (cur_index == index)
|
|
break;
|
|
|
|
of_node_put(node);
|
|
node = NULL;
|
|
args = NULL;
|
|
cur_index++;
|
|
}
|
|
|
|
if (!node) {
|
|
/*
|
|
* args w/o node indicates that the loop above has stopped at
|
|
* the 'hole' cell. Report this differently.
|
|
*/
|
|
if (args)
|
|
ret = -EEXIST;
|
|
else
|
|
ret = -ENOENT;
|
|
goto err0;
|
|
}
|
|
|
|
if (out_node)
|
|
*out_node = node;
|
|
if (out_args)
|
|
*out_args = args;
|
|
|
|
return 0;
|
|
err1:
|
|
of_node_put(node);
|
|
err0:
|
|
pr_debug("%s failed with status %d\n", __func__, ret);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(of_parse_phandles_with_args);
|
|
|
|
/**
|
|
* prom_add_property - Add a property to a node
|
|
*/
|
|
int prom_add_property(struct device_node *np, struct property *prop)
|
|
{
|
|
struct property **next;
|
|
unsigned long flags;
|
|
|
|
prop->next = NULL;
|
|
write_lock_irqsave(&devtree_lock, flags);
|
|
next = &np->properties;
|
|
while (*next) {
|
|
if (strcmp(prop->name, (*next)->name) == 0) {
|
|
/* duplicate ! don't insert it */
|
|
write_unlock_irqrestore(&devtree_lock, flags);
|
|
return -1;
|
|
}
|
|
next = &(*next)->next;
|
|
}
|
|
*next = prop;
|
|
write_unlock_irqrestore(&devtree_lock, flags);
|
|
|
|
#ifdef CONFIG_PROC_DEVICETREE
|
|
/* try to add to proc as well if it was initialized */
|
|
if (np->pde)
|
|
proc_device_tree_add_prop(np->pde, prop);
|
|
#endif /* CONFIG_PROC_DEVICETREE */
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* prom_remove_property - Remove a property from a node.
|
|
*
|
|
* Note that we don't actually remove it, since we have given out
|
|
* who-knows-how-many pointers to the data using get-property.
|
|
* Instead we just move the property to the "dead properties"
|
|
* list, so it won't be found any more.
|
|
*/
|
|
int prom_remove_property(struct device_node *np, struct property *prop)
|
|
{
|
|
struct property **next;
|
|
unsigned long flags;
|
|
int found = 0;
|
|
|
|
write_lock_irqsave(&devtree_lock, flags);
|
|
next = &np->properties;
|
|
while (*next) {
|
|
if (*next == prop) {
|
|
/* found the node */
|
|
*next = prop->next;
|
|
prop->next = np->deadprops;
|
|
np->deadprops = prop;
|
|
found = 1;
|
|
break;
|
|
}
|
|
next = &(*next)->next;
|
|
}
|
|
write_unlock_irqrestore(&devtree_lock, flags);
|
|
|
|
if (!found)
|
|
return -ENODEV;
|
|
|
|
#ifdef CONFIG_PROC_DEVICETREE
|
|
/* try to remove the proc node as well */
|
|
if (np->pde)
|
|
proc_device_tree_remove_prop(np->pde, prop);
|
|
#endif /* CONFIG_PROC_DEVICETREE */
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* prom_update_property - Update a property in a node.
|
|
*
|
|
* Note that we don't actually remove it, since we have given out
|
|
* who-knows-how-many pointers to the data using get-property.
|
|
* Instead we just move the property to the "dead properties" list,
|
|
* and add the new property to the property list
|
|
*/
|
|
int prom_update_property(struct device_node *np,
|
|
struct property *newprop,
|
|
struct property *oldprop)
|
|
{
|
|
struct property **next;
|
|
unsigned long flags;
|
|
int found = 0;
|
|
|
|
write_lock_irqsave(&devtree_lock, flags);
|
|
next = &np->properties;
|
|
while (*next) {
|
|
if (*next == oldprop) {
|
|
/* found the node */
|
|
newprop->next = oldprop->next;
|
|
*next = newprop;
|
|
oldprop->next = np->deadprops;
|
|
np->deadprops = oldprop;
|
|
found = 1;
|
|
break;
|
|
}
|
|
next = &(*next)->next;
|
|
}
|
|
write_unlock_irqrestore(&devtree_lock, flags);
|
|
|
|
if (!found)
|
|
return -ENODEV;
|
|
|
|
#ifdef CONFIG_PROC_DEVICETREE
|
|
/* try to add to proc as well if it was initialized */
|
|
if (np->pde)
|
|
proc_device_tree_update_prop(np->pde, newprop, oldprop);
|
|
#endif /* CONFIG_PROC_DEVICETREE */
|
|
|
|
return 0;
|
|
}
|
|
|
|
#if defined(CONFIG_OF_DYNAMIC)
|
|
/*
|
|
* Support for dynamic device trees.
|
|
*
|
|
* On some platforms, the device tree can be manipulated at runtime.
|
|
* The routines in this section support adding, removing and changing
|
|
* device tree nodes.
|
|
*/
|
|
|
|
/**
|
|
* of_attach_node - Plug a device node into the tree and global list.
|
|
*/
|
|
void of_attach_node(struct device_node *np)
|
|
{
|
|
unsigned long flags;
|
|
|
|
write_lock_irqsave(&devtree_lock, flags);
|
|
np->sibling = np->parent->child;
|
|
np->allnext = allnodes;
|
|
np->parent->child = np;
|
|
allnodes = np;
|
|
write_unlock_irqrestore(&devtree_lock, flags);
|
|
}
|
|
|
|
/**
|
|
* of_detach_node - "Unplug" a node from the device tree.
|
|
*
|
|
* The caller must hold a reference to the node. The memory associated with
|
|
* the node is not freed until its refcount goes to zero.
|
|
*/
|
|
void of_detach_node(struct device_node *np)
|
|
{
|
|
struct device_node *parent;
|
|
unsigned long flags;
|
|
|
|
write_lock_irqsave(&devtree_lock, flags);
|
|
|
|
parent = np->parent;
|
|
if (!parent)
|
|
goto out_unlock;
|
|
|
|
if (allnodes == np)
|
|
allnodes = np->allnext;
|
|
else {
|
|
struct device_node *prev;
|
|
for (prev = allnodes;
|
|
prev->allnext != np;
|
|
prev = prev->allnext)
|
|
;
|
|
prev->allnext = np->allnext;
|
|
}
|
|
|
|
if (parent->child == np)
|
|
parent->child = np->sibling;
|
|
else {
|
|
struct device_node *prevsib;
|
|
for (prevsib = np->parent->child;
|
|
prevsib->sibling != np;
|
|
prevsib = prevsib->sibling)
|
|
;
|
|
prevsib->sibling = np->sibling;
|
|
}
|
|
|
|
of_node_set_flag(np, OF_DETACHED);
|
|
|
|
out_unlock:
|
|
write_unlock_irqrestore(&devtree_lock, flags);
|
|
}
|
|
#endif /* defined(CONFIG_OF_DYNAMIC) */
|
|
|