base.c 33.9 KB
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/*
 * Procedures for creating, accessing and interpreting the device tree.
 *
 * Paul Mackerras	August 1996.
 * Copyright (C) 1996-2005 Paul Mackerras.
 *
 *  Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
 *    {engebret|bergner}@us.ibm.com
 *
 *  Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net
 *
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 *  Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell and
 *  Grant Likely.
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 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */
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#include <linux/ctype.h>
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#include <linux/module.h>
#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 alias_prop - Alias property in 'aliases' node
 * @link:	List node to link the structure in aliases_lookup list
 * @alias:	Alias property name
 * @np:		Pointer to device_node that the alias stands for
 * @id:		Index value from end of alias name
 * @stem:	Alias string without the index
 *
 * The structure represents one alias property of 'aliases' node as
 * an entry in aliases_lookup list.
 */
struct alias_prop {
	struct list_head link;
	const char *alias;
	struct device_node *np;
	int id;
	char stem[0];
};

static LIST_HEAD(aliases_lookup);

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struct device_node *allnodes;
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struct device_node *of_chosen;
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struct device_node *of_aliases;

static DEFINE_MUTEX(of_aliases_mutex);
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/* use when traversing tree through the allnext, child, sibling,
 * or parent members of struct device_node.
 */
DEFINE_RWLOCK(devtree_lock);
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int of_n_addr_cells(struct device_node *np)
{
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	const __be32 *ip;
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	do {
		if (np->parent)
			np = np->parent;
		ip = of_get_property(np, "#address-cells", NULL);
		if (ip)
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			return be32_to_cpup(ip);
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	} while (np->parent);
	/* No #address-cells property for the root node */
	return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
}
EXPORT_SYMBOL(of_n_addr_cells);

int of_n_size_cells(struct device_node *np)
{
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	const __be32 *ip;
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	do {
		if (np->parent)
			np = np->parent;
		ip = of_get_property(np, "#size-cells", NULL);
		if (ip)
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			return be32_to_cpup(ip);
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	} while (np->parent);
	/* No #size-cells property for the root node */
	return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
}
EXPORT_SYMBOL(of_n_size_cells);

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#if defined(CONFIG_OF_DYNAMIC)
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/**
 *	of_node_get - Increment refcount of a node
 *	@node:	Node to inc refcount, NULL is supported to
 *		simplify writing of callers
 *
 *	Returns node.
 */
struct device_node *of_node_get(struct device_node *node)
{
	if (node)
		kref_get(&node->kref);
	return node;
}
EXPORT_SYMBOL(of_node_get);

static inline struct device_node *kref_to_device_node(struct kref *kref)
{
	return container_of(kref, struct device_node, kref);
}

/**
 *	of_node_release - release a dynamically allocated node
 *	@kref:  kref element of the node to be released
 *
 *	In of_node_put() this function is passed to kref_put()
 *	as the destructor.
 */
static void of_node_release(struct kref *kref)
{
	struct device_node *node = kref_to_device_node(kref);
	struct property *prop = node->properties;

	/* We should never be releasing nodes that haven't been detached. */
	if (!of_node_check_flag(node, OF_DETACHED)) {
		pr_err("ERROR: Bad of_node_put() on %s\n", node->full_name);
		dump_stack();
		kref_init(&node->kref);
		return;
	}

	if (!of_node_check_flag(node, OF_DYNAMIC))
		return;

	while (prop) {
		struct property *next = prop->next;
		kfree(prop->name);
		kfree(prop->value);
		kfree(prop);
		prop = next;

		if (!prop) {
			prop = node->deadprops;
			node->deadprops = NULL;
		}
	}
	kfree(node->full_name);
	kfree(node->data);
	kfree(node);
}

/**
 *	of_node_put - Decrement refcount of a node
 *	@node:	Node to dec refcount, NULL is supported to
 *		simplify writing of callers
 *
 */
void of_node_put(struct device_node *node)
{
	if (node)
		kref_put(&node->kref, of_node_release);
}
EXPORT_SYMBOL(of_node_put);
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#endif /* CONFIG_OF_DYNAMIC */
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struct property *of_find_property(const struct device_node *np,
				  const char *name,
				  int *lenp)
{
	struct property *pp;

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	if (!np)
		return NULL;

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	read_lock(&devtree_lock);
	for (pp = np->properties; pp != 0; pp = pp->next) {
		if (of_prop_cmp(pp->name, name) == 0) {
			if (lenp != 0)
				*lenp = pp->length;
			break;
		}
	}
	read_unlock(&devtree_lock);

	return pp;
}
EXPORT_SYMBOL(of_find_property);

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/**
 * of_find_all_nodes - Get next node in global list
 * @prev:	Previous node or NULL to start iteration
 *		of_node_put() will be called on it
 *
 * Returns a node pointer with refcount incremented, use
 * of_node_put() on it when done.
 */
struct device_node *of_find_all_nodes(struct device_node *prev)
{
	struct device_node *np;

	read_lock(&devtree_lock);
	np = prev ? prev->allnext : allnodes;
	for (; np != NULL; np = np->allnext)
		if (of_node_get(np))
			break;
	of_node_put(prev);
	read_unlock(&devtree_lock);
	return np;
}
EXPORT_SYMBOL(of_find_all_nodes);

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/*
 * Find a property with a given name for a given node
 * and return the value.
 */
const void *of_get_property(const struct device_node *np, const char *name,
			 int *lenp)
{
	struct property *pp = of_find_property(np, name, lenp);

	return pp ? pp->value : NULL;
}
EXPORT_SYMBOL(of_get_property);
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/** Checks if the given "compat" string matches one of the strings in
 * the device's "compatible" property
 */
int of_device_is_compatible(const struct device_node *device,
		const char *compat)
{
	const char* cp;
	int cplen, l;

	cp = of_get_property(device, "compatible", &cplen);
	if (cp == NULL)
		return 0;
	while (cplen > 0) {
		if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
			return 1;
		l = strlen(cp) + 1;
		cp += l;
		cplen -= l;
	}

	return 0;
}
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.
 *
 * Returns true if the root node has the given value in its
 * compatible property.
 */
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int of_machine_is_compatible(const char *compat)
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{
	struct device_node *root;
	int rc = 0;

	root = of_find_node_by_path("/");
	if (root) {
		rc = of_device_is_compatible(root, compat);
		of_node_put(root);
	}
	return rc;
}
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EXPORT_SYMBOL(of_machine_is_compatible);
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/**
 *  of_device_is_available - check if a device is available for use
 *
 *  @device: Node to check for availability
 *
 *  Returns 1 if the status property is absent or set to "okay" or "ok",
 *  0 otherwise
 */
int of_device_is_available(const struct device_node *device)
{
	const char *status;
	int statlen;

	status = of_get_property(device, "status", &statlen);
	if (status == NULL)
		return 1;

	if (statlen > 0) {
		if (!strcmp(status, "okay") || !strcmp(status, "ok"))
			return 1;
	}

	return 0;
}
EXPORT_SYMBOL(of_device_is_available);

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/**
 *	of_get_parent - Get a node's parent if any
 *	@node:	Node to get parent
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_get_parent(const struct device_node *node)
{
	struct device_node *np;

	if (!node)
		return NULL;

	read_lock(&devtree_lock);
	np = of_node_get(node->parent);
	read_unlock(&devtree_lock);
	return np;
}
EXPORT_SYMBOL(of_get_parent);
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/**
 *	of_get_next_parent - Iterate to a node's parent
 *	@node:	Node to get parent of
 *
 * 	This is like of_get_parent() except that it drops the
 * 	refcount on the passed node, making it suitable for iterating
 * 	through a node's parents.
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_get_next_parent(struct device_node *node)
{
	struct device_node *parent;

	if (!node)
		return NULL;

	read_lock(&devtree_lock);
	parent = of_node_get(node->parent);
	of_node_put(node);
	read_unlock(&devtree_lock);
	return parent;
}

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/**
 *	of_get_next_child - Iterate a node childs
 *	@node:	parent node
 *	@prev:	previous child of the parent node, or NULL to get first
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_get_next_child(const struct device_node *node,
	struct device_node *prev)
{
	struct device_node *next;

	read_lock(&devtree_lock);
	next = prev ? prev->sibling : node->child;
	for (; next; next = next->sibling)
		if (of_node_get(next))
			break;
	of_node_put(prev);
	read_unlock(&devtree_lock);
	return next;
}
EXPORT_SYMBOL(of_get_next_child);
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/**
 *	of_find_node_by_path - Find a node matching a full OF path
 *	@path:	The full path to match
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_node_by_path(const char *path)
{
	struct device_node *np = allnodes;

	read_lock(&devtree_lock);
	for (; np; np = np->allnext) {
		if (np->full_name && (of_node_cmp(np->full_name, path) == 0)
		    && of_node_get(np))
			break;
	}
	read_unlock(&devtree_lock);
	return np;
}
EXPORT_SYMBOL(of_find_node_by_path);

/**
 *	of_find_node_by_name - Find a node by its "name" property
 *	@from:	The node to start searching from or NULL, the node
 *		you pass will not be searched, only the next one
 *		will; typically, you pass what the previous call
 *		returned. of_node_put() will be called on it
 *	@name:	The name string to match against
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_node_by_name(struct device_node *from,
	const char *name)
{
	struct device_node *np;

	read_lock(&devtree_lock);
	np = from ? from->allnext : allnodes;
	for (; np; np = np->allnext)
		if (np->name && (of_node_cmp(np->name, name) == 0)
		    && of_node_get(np))
			break;
	of_node_put(from);
	read_unlock(&devtree_lock);
	return np;
}
EXPORT_SYMBOL(of_find_node_by_name);

/**
 *	of_find_node_by_type - Find a node by its "device_type" property
 *	@from:	The node to start searching from, or NULL to start searching
 *		the entire device tree. The node you pass will not be
 *		searched, only the next one will; typically, you pass
 *		what the previous call returned. of_node_put() will be
 *		called on from for you.
 *	@type:	The type string to match against
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_node_by_type(struct device_node *from,
	const char *type)
{
	struct device_node *np;

	read_lock(&devtree_lock);
	np = from ? from->allnext : allnodes;
	for (; np; np = np->allnext)
		if (np->type && (of_node_cmp(np->type, type) == 0)
		    && of_node_get(np))
			break;
	of_node_put(from);
	read_unlock(&devtree_lock);
	return np;
}
EXPORT_SYMBOL(of_find_node_by_type);

/**
 *	of_find_compatible_node - Find a node based on type and one of the
 *                                tokens in its "compatible" property
 *	@from:		The node to start searching from or NULL, the node
 *			you pass will not be searched, only the next one
 *			will; typically, you pass what the previous call
 *			returned. of_node_put() will be called on it
 *	@type:		The type string to match "device_type" or NULL to ignore
 *	@compatible:	The string to match to one of the tokens in the device
 *			"compatible" list.
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_compatible_node(struct device_node *from,
	const char *type, const char *compatible)
{
	struct device_node *np;

	read_lock(&devtree_lock);
	np = from ? from->allnext : allnodes;
	for (; np; np = np->allnext) {
		if (type
		    && !(np->type && (of_node_cmp(np->type, type) == 0)))
			continue;
		if (of_device_is_compatible(np, compatible) && of_node_get(np))
			break;
	}
	of_node_put(from);
	read_unlock(&devtree_lock);
	return np;
}
EXPORT_SYMBOL(of_find_compatible_node);
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/**
 *	of_find_node_with_property - Find a node which has a property with
 *                                   the given name.
 *	@from:		The node to start searching from or NULL, the node
 *			you pass will not be searched, only the next one
 *			will; typically, you pass what the previous call
 *			returned. of_node_put() will be called on it
 *	@prop_name:	The name of the property to look for.
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_node_with_property(struct device_node *from,
	const char *prop_name)
{
	struct device_node *np;
	struct property *pp;

	read_lock(&devtree_lock);
	np = from ? from->allnext : allnodes;
	for (; np; np = np->allnext) {
		for (pp = np->properties; pp != 0; pp = pp->next) {
			if (of_prop_cmp(pp->name, prop_name) == 0) {
				of_node_get(np);
				goto out;
			}
		}
	}
out:
	of_node_put(from);
	read_unlock(&devtree_lock);
	return np;
}
EXPORT_SYMBOL(of_find_node_with_property);

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static const struct of_device_id *of_match_compat(const struct of_device_id *matches,
						  const char *compat)
{
	while (matches->name[0] || matches->type[0] || matches->compatible[0]) {
		const char *cp = matches->compatible;
		int len = strlen(cp);

		if (len > 0 && of_compat_cmp(compat, cp, len) == 0)
			return matches;

		matches++;
	}

	return NULL;
}

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/**
 * of_match_node - Tell if an device_node has a matching of_match structure
 *	@matches:	array of of device match structures to search in
 *	@node:		the of device structure to match against
 *
 *	Low level utility function used by device matching.
 */
const struct of_device_id *of_match_node(const struct of_device_id *matches,
					 const struct device_node *node)
{
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	struct property *prop;
	const char *cp;

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	if (!matches)
		return NULL;

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	of_property_for_each_string(node, "compatible", prop, cp) {
		const struct of_device_id *match = of_match_compat(matches, cp);
		if (match)
			return match;
	}

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	while (matches->name[0] || matches->type[0] || matches->compatible[0]) {
		int match = 1;
		if (matches->name[0])
			match &= node->name
				&& !strcmp(matches->name, node->name);
		if (matches->type[0])
			match &= node->type
				&& !strcmp(matches->type, node->type);
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		if (match && !matches->compatible[0])
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			return matches;
		matches++;
	}
	return NULL;
}
EXPORT_SYMBOL(of_match_node);

/**
 *	of_find_matching_node - Find a node based on an of_device_id match
 *				table.
 *	@from:		The node to start searching from or NULL, the node
 *			you pass will not be searched, only the next one
 *			will; typically, you pass what the previous call
 *			returned. of_node_put() will be called on it
 *	@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);
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/**
 * 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
 *
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 * 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.
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 *
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 * This routine returns 0 on success, <0 on failure.
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 */
int of_modalias_node(struct device_node *node, char *modalias, int len)
{
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	const char *compatible, *p;
	int cplen;
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	compatible = of_get_property(node, "compatible", &cplen);
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	if (!compatible || strlen(compatible) > cplen)
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		return -ENODEV;
	p = strchr(compatible, ',');
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	strlcpy(modalias, p ? p + 1 : compatible, len);
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	return 0;
}
EXPORT_SYMBOL_GPL(of_modalias_node);

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/**
 * 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);

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/**
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 * of_property_read_u32_array - Find and read an array of 32 bit integers
 * from a property.
 *
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 * @np:		device node from which the property value is to be read.
 * @propname:	name of the property to be searched.
 * @out_value:	pointer to return value, modified only if return value is 0.
 *
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 * Search for a property in a device node and read 32-bit value(s) from
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 * it. Returns 0 on success, -EINVAL if the property does not exist,
 * -ENODATA if property does not have a value, and -EOVERFLOW if the
 * property data isn't large enough.
 *
 * The out_value is modified only if a valid u32 value can be decoded.
 */
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int of_property_read_u32_array(const struct device_node *np,
			       const char *propname, u32 *out_values,
			       size_t sz)
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{
	struct property *prop = of_find_property(np, propname, NULL);
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	const __be32 *val;
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	if (!prop)
		return -EINVAL;
	if (!prop->value)
		return -ENODATA;
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	if ((sz * sizeof(*out_values)) > prop->length)
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		return -EOVERFLOW;
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	val = prop->value;
	while (sz--)
		*out_values++ = be32_to_cpup(val++);
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	return 0;
}
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EXPORT_SYMBOL_GPL(of_property_read_u32_array);
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/**
 * of_property_read_u64 - Find and read a 64 bit integer from a property
 * @np:		device node from which the property value is to be read.
 * @propname:	name of the property to be searched.
 * @out_value:	pointer to return value, modified only if return value is 0.
 *
 * Search for a property in a device node and read a 64-bit value from
 * it. Returns 0 on success, -EINVAL if the property does not exist,
 * -ENODATA if property does not have a value, and -EOVERFLOW if the
 * property data isn't large enough.
 *
 * The out_value is modified only if a valid u64 value can be decoded.
 */
int of_property_read_u64(const struct device_node *np, const char *propname,
			 u64 *out_value)
{
	struct property *prop = of_find_property(np, propname, NULL);

	if (!prop)
		return -EINVAL;
	if (!prop->value)
		return -ENODATA;
	if (sizeof(*out_value) > prop->length)
		return -EOVERFLOW;
	*out_value = of_read_number(prop->value, 2);
	return 0;
}
EXPORT_SYMBOL_GPL(of_property_read_u64);

710 711 712 713 714 715 716 717 718 719 720 721 722 723 724
/**
 * of_property_read_string - Find and read a string from a property
 * @np:		device node from which the property value is to be read.
 * @propname:	name of the property to be searched.
 * @out_string:	pointer to null terminated return string, modified only if
 *		return value is 0.
 *
 * Search for a property in a device tree node and retrieve a null
 * terminated string value (pointer to data, not a copy). Returns 0 on
 * success, -EINVAL if the property does not exist, -ENODATA if property
 * does not have a value, and -EILSEQ if the string is not null-terminated
 * within the length of the property data.
 *
 * The out_string pointer is modified only if a valid string can be decoded.
 */
725
int of_property_read_string(struct device_node *np, const char *propname,
726
				const char **out_string)
727 728 729 730 731 732 733 734 735 736 737 738 739
{
	struct property *prop = of_find_property(np, propname, NULL);
	if (!prop)
		return -EINVAL;
	if (!prop->value)
		return -ENODATA;
	if (strnlen(prop->value, prop->length) >= prop->length)
		return -EILSEQ;
	*out_string = prop->value;
	return 0;
}
EXPORT_SYMBOL_GPL(of_property_read_string);

740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776
/**
 * of_property_read_string_index - Find and read a string from a multiple
 * strings property.
 * @np:		device node from which the property value is to be read.
 * @propname:	name of the property to be searched.
 * @index:	index of the string in the list of strings
 * @out_string:	pointer to null terminated return string, modified only if
 *		return value is 0.
 *
 * Search for a property in a device tree node and retrieve a null
 * terminated string value (pointer to data, not a copy) in the list of strings
 * contained in that property.
 * Returns 0 on success, -EINVAL if the property does not exist, -ENODATA if
 * property does not have a value, and -EILSEQ if the string is not
 * null-terminated within the length of the property data.
 *
 * The out_string pointer is modified only if a valid string can be decoded.
 */
int of_property_read_string_index(struct device_node *np, const char *propname,
				  int index, const char **output)
{
	struct property *prop = of_find_property(np, propname, NULL);
	int i = 0;
	size_t l = 0, total = 0;
	const char *p;

	if (!prop)
		return -EINVAL;
	if (!prop->value)
		return -ENODATA;
	if (strnlen(prop->value, prop->length) >= prop->length)
		return -EILSEQ;

	p = prop->value;

	for (i = 0; total < prop->length; total += l, p += l) {
		l = strlen(p) + 1;
777
		if (i++ == index) {
778 779 780 781 782 783 784 785
			*output = p;
			return 0;
		}
	}
	return -ENODATA;
}
EXPORT_SYMBOL_GPL(of_property_read_string_index);

786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821
/**
 * of_property_match_string() - Find string in a list and return index
 * @np: pointer to node containing string list property
 * @propname: string list property name
 * @string: pointer to string to search for in string list
 *
 * This function searches a string list property and returns the index
 * of a specific string value.
 */
int of_property_match_string(struct device_node *np, const char *propname,
			     const char *string)
{
	struct property *prop = of_find_property(np, propname, NULL);
	size_t l;
	int i;
	const char *p, *end;

	if (!prop)
		return -EINVAL;
	if (!prop->value)
		return -ENODATA;

	p = prop->value;
	end = p + prop->length;

	for (i = 0; p < end; i++, p += l) {
		l = strlen(p) + 1;
		if (p + l > end)
			return -EILSEQ;
		pr_debug("comparing %s with %s\n", string, p);
		if (strcmp(string, p) == 0)
			return i; /* Found it; return index */
	}
	return -ENODATA;
}
EXPORT_SYMBOL_GPL(of_property_match_string);
822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850

/**
 * of_property_count_strings - Find and return the number of strings from a
 * multiple strings property.
 * @np:		device node from which the property value is to be read.
 * @propname:	name of the property to be searched.
 *
 * Search for a property in a device tree node and retrieve the number of null
 * terminated string contain in it. Returns the number of strings on
 * success, -EINVAL if the property does not exist, -ENODATA if property
 * does not have a value, and -EILSEQ if the string is not null-terminated
 * within the length of the property data.
 */
int of_property_count_strings(struct device_node *np, const char *propname)
{
	struct property *prop = of_find_property(np, propname, NULL);
	int i = 0;
	size_t l = 0, total = 0;
	const char *p;

	if (!prop)
		return -EINVAL;
	if (!prop->value)
		return -ENODATA;
	if (strnlen(prop->value, prop->length) >= prop->length)
		return -EILSEQ;

	p = prop->value;

851
	for (i = 0; total < prop->length; total += l, p += l, i++)
852
		l = strlen(p) + 1;
853

854 855 856 857
	return i;
}
EXPORT_SYMBOL_GPL(of_property_count_strings);

858 859 860 861 862 863 864 865 866 867 868 869 870
/**
 * 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)
{
G
Grant Likely 已提交
871
	const __be32 *phandle;
872 873 874 875 876 877
	int size;

	phandle = of_get_property(np, phandle_name, &size);
	if ((!phandle) || (size < sizeof(*phandle) * (index + 1)))
		return NULL;

G
Grant Likely 已提交
878
	return of_find_node_by_phandle(be32_to_cpup(phandle + index));
879 880 881
}
EXPORT_SYMBOL(of_parse_phandle);

882
/**
883
 * of_parse_phandle_with_args() - Find a node pointed by phandle in a list
884 885 886 887
 * @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
888
 * @out_args:	optional pointer to output arguments structure (will be filled)
889 890
 *
 * This function is useful to parse lists of phandles and their arguments.
891 892 893 894 895
 * Returns 0 on success and fills out_args, on error returns appropriate
 * errno value.
 *
 * Caller is responsible to call of_node_put() on the returned out_args->node
 * pointer.
896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911
 *
 * 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:
912
 * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);
913
 */
914
int of_parse_phandle_with_args(struct device_node *np, const char *list_name,
915
				const char *cells_name, int index,
916
				struct of_phandle_args *out_args)
917
{
918 919 920
	const __be32 *list, *list_end;
	int size, cur_index = 0;
	uint32_t count = 0;
921
	struct device_node *node = NULL;
922
	phandle phandle;
923

924
	/* Retrieve the phandle list property */
925
	list = of_get_property(np, list_name, &size);
926 927
	if (!list)
		return -EINVAL;
928 929
	list_end = list + size / sizeof(*list);

930
	/* Loop over the phandles until all the requested entry is found */
931
	while (list < list_end) {
932
		count = 0;
933

934 935 936 937
		/*
		 * If phandle is 0, then it is an empty entry with no
		 * arguments.  Skip forward to the next entry.
		 */
G
Grant Likely 已提交
938
		phandle = be32_to_cpup(list++);
939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955
		if (phandle) {
			/*
			 * Find the provider node and parse the #*-cells
			 * property to determine the argument length
			 */
			node = of_find_node_by_phandle(phandle);
			if (!node) {
				pr_err("%s: could not find phandle\n",
					 np->full_name);
				break;
			}
			if (of_property_read_u32(node, cells_name, &count)) {
				pr_err("%s: could not get %s for %s\n",
					 np->full_name, cells_name,
					 node->full_name);
				break;
			}
956

957 958 959 960 961 962 963 964 965
			/*
			 * Make sure that the arguments actually fit in the
			 * remaining property data length
			 */
			if (list + count > list_end) {
				pr_err("%s: arguments longer than property\n",
					 np->full_name);
				break;
			}
966 967
		}

968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987
		/*
		 * All of the error cases above bail out of the loop, so at
		 * this point, the parsing is successful. If the requested
		 * index matches, then fill the out_args structure and return,
		 * or return -ENOENT for an empty entry.
		 */
		if (cur_index == index) {
			if (!phandle)
				return -ENOENT;

			if (out_args) {
				int i;
				if (WARN_ON(count > MAX_PHANDLE_ARGS))
					count = MAX_PHANDLE_ARGS;
				out_args->np = node;
				out_args->args_count = count;
				for (i = 0; i < count; i++)
					out_args->args[i] = be32_to_cpup(list++);
			}
			return 0;
988 989 990 991
		}

		of_node_put(node);
		node = NULL;
992
		list += count;
993 994 995
		cur_index++;
	}

996 997 998 999
	/* Loop exited without finding a valid entry; return an error */
	if (node)
		of_node_put(node);
	return -EINVAL;
1000
}
1001
EXPORT_SYMBOL(of_parse_phandle_with_args);
1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117

/**
 * 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;
}
1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188

#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) */

1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221
static void of_alias_add(struct alias_prop *ap, struct device_node *np,
			 int id, const char *stem, int stem_len)
{
	ap->np = np;
	ap->id = id;
	strncpy(ap->stem, stem, stem_len);
	ap->stem[stem_len] = 0;
	list_add_tail(&ap->link, &aliases_lookup);
	pr_debug("adding DT alias:%s: stem=%s id=%i node=%s\n",
		 ap->alias, ap->stem, ap->id, np ? np->full_name : NULL);
}

/**
 * of_alias_scan - Scan all properties of 'aliases' node
 *
 * The function scans all the properties of 'aliases' node and populate
 * the the global lookup table with the properties.  It returns the
 * number of alias_prop found, or error code in error case.
 *
 * @dt_alloc:	An allocator that provides a virtual address to memory
 *		for the resulting tree
 */
void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
{
	struct property *pp;

	of_chosen = of_find_node_by_path("/chosen");
	if (of_chosen == NULL)
		of_chosen = of_find_node_by_path("/chosen@0");
	of_aliases = of_find_node_by_path("/aliases");
	if (!of_aliases)
		return;

1222
	for_each_property_of_node(of_aliases, pp) {
1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284
		const char *start = pp->name;
		const char *end = start + strlen(start);
		struct device_node *np;
		struct alias_prop *ap;
		int id, len;

		/* Skip those we do not want to proceed */
		if (!strcmp(pp->name, "name") ||
		    !strcmp(pp->name, "phandle") ||
		    !strcmp(pp->name, "linux,phandle"))
			continue;

		np = of_find_node_by_path(pp->value);
		if (!np)
			continue;

		/* walk the alias backwards to extract the id and work out
		 * the 'stem' string */
		while (isdigit(*(end-1)) && end > start)
			end--;
		len = end - start;

		if (kstrtoint(end, 10, &id) < 0)
			continue;

		/* Allocate an alias_prop with enough space for the stem */
		ap = dt_alloc(sizeof(*ap) + len + 1, 4);
		if (!ap)
			continue;
		ap->alias = start;
		of_alias_add(ap, np, id, start, len);
	}
}

/**
 * of_alias_get_id - Get alias id for the given device_node
 * @np:		Pointer to the given device_node
 * @stem:	Alias stem of the given device_node
 *
 * The function travels the lookup table to get alias id for the given
 * device_node and alias stem.  It returns the alias id if find it.
 */
int of_alias_get_id(struct device_node *np, const char *stem)
{
	struct alias_prop *app;
	int id = -ENODEV;

	mutex_lock(&of_aliases_mutex);
	list_for_each_entry(app, &aliases_lookup, link) {
		if (strcmp(app->stem, stem) != 0)
			continue;

		if (np == app->np) {
			id = app->id;
			break;
		}
	}
	mutex_unlock(&of_aliases_mutex);

	return id;
}
EXPORT_SYMBOL_GPL(of_alias_get_id);
1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325

const __be32 *of_prop_next_u32(struct property *prop, const __be32 *cur,
			       u32 *pu)
{
	const void *curv = cur;

	if (!prop)
		return NULL;

	if (!cur) {
		curv = prop->value;
		goto out_val;
	}

	curv += sizeof(*cur);
	if (curv >= prop->value + prop->length)
		return NULL;

out_val:
	*pu = be32_to_cpup(curv);
	return curv;
}
EXPORT_SYMBOL_GPL(of_prop_next_u32);

const char *of_prop_next_string(struct property *prop, const char *cur)
{
	const void *curv = cur;

	if (!prop)
		return NULL;

	if (!cur)
		return prop->value;

	curv += strlen(cur) + 1;
	if (curv >= prop->value + prop->length)
		return NULL;

	return curv;
}
EXPORT_SYMBOL_GPL(of_prop_next_string);